CMP Journal 2026-10-14
Statistics
Nature: 28
Nature Nanotechnology: 2
Physical Review Letters: 7
Physical Review X: 2
arXiv: 260
Research Square: 2
Nature
Catalytic transfer of carbon atoms enables spirofusion of C-C σ-bonds
Original Paper | Synthetic chemistry methodology | 2026-10-13 20:00 EDT
Hayato Fujimoto, Masayuki Mizutani, Kazuya Imachi, Teruki Nishioka, Reona Ikeda, Mamoru Tobisu
Spirocyclic frameworks, polycyclic structures in which two rings share a single carbon atom, constitute key structural motifs across diverse areas, including optoelectronic and hole-transporting materials1-3, ligand design for coordination complexes4-6, and numerous natural products7. In a spiro skeleton, the two molecular units adopt an orthogonal arrangement, generating a rigid three-dimensional (3D) architecture. Introducing a single carbon atom to join two components to form the spiro centre therefore represents a direct strategy for constructing such frameworks. Previous carbon-atom-transfer approaches have largely relied on π-bond reactivity, whereas controlled insertion of a carbon atom into C-C σ-bonds remains challenging8-11. Here we report a rhodium-catalysed spiro-carbon-atom insertion reaction that converts biphenylene substrates into spirocyclic structures through sequential C-C bond activation. Using N-isocyanoiminophosphorane (PINC)12-14 as an atomic carbon equivalent, the reaction forms four new C-C bonds at a spiro centre. The transformation enables both homo- and cross-spirofusion of biphenylenes and can be extended to reactions combining σ- and π-bond activation. These results establish a catalytic strategy for constructing structurally complex spirocyclic frameworks through C-C σ-bond activation, with a single carbon atom serving as a central linchpin.
Synthetic chemistry methodology, Homogeneous catalysis
Structural basis of ligand recognition and gating in mosquito IRs
Original Paper | Cryoelectron microscopy | 2026-10-13 20:00 EDT
Li Xu
(徐莉), Xin Wang
(王鑫), Xuebo Quan
(全学波), Stephen T. Ferguson, Dong Liu
(刘东), Jiawei Chen
(陈嘉伟), Sai Wang
(王赛), Simin Liang
(梁思敏), Gaoxingyu Huang
(黄高兴宇), Kai Huang
(黄恺), Feng Liu
(柳峰), Xiaojing Pan
(潘孝敬)
Ionotropic receptors (IRs) are essential for insect olfaction, enabling the detection of carboxylic acids, amines, moisture, and temperature cues that mediate critical behaviors, including mosquito host-seeking 1,2. However, the structural mechanisms underlying ligand specificity and channel activation in these receptors remain unclear. Here, we report cryo-electron microscopy (cryo-EM) structures and functional validation of the IR8a-IR75k complex from the malaria mosquito Anopheles stephensi, a carboxylic acid detector, captured in four states: the ligand-free full-length closed form (apo state), the ligand induced full-length open state, and the nonanoic acid (NA)- and octanoic acid (OA)-bound extracellular domains. These structures reveal a dynamic ligand-binding pocket in IR75k, in which specificity is determined by alkyl chain length and carboxylate geometry. Ligand binding triggers closure of IR75k’s bilobed ligand binding domain (LBD), and this conformational change propagates through conserved mechanical linkers to the transmembrane domain (TMD), functioning as a molecular lever that dilates the pore via outward displacement of transmembrane helices. This gating mechanism was further corroborated by molecular dynamics simulations and electrophysiology. These insights provide an atomic resolution view of IR mediated host detection in mosquitoes and establish a foundation for the rational design of next generation mosquito control strategies targeting host-seeking behavior.
Cryoelectron microscopy, Ligand-gated ion channels
Evidence for multi-Li+ clustering in lithium-ion battery electrolytes
Original Paper | Batteries | 2026-10-13 20:00 EDT
James M. Stevenson, Garvit Agarwal, Sibali Debnath, Zachary K. Goldsmith, Monosij Mondal, Asya Svirinovsky-Arbeli, In Won Yeu, Amy S. Metlay, Yongbeom Kwon, Lakshmi Bhai, Rishabh D. Guha, Eric G. Keeler, John L. Weber, Daniel A. Steingart, Lauren E. Marbella, Alexander Urban, Leif D. Jacobson, Mathew D. Halls, Richard A. Friesner
In lithium-ion batteries, the bulk solvation structure of the electrolyte is a major determinant of the physical and electrochemical properties of the cell, for example, conductivity, viscosity, salt dissociation and subsequent reactivity, the electrochemical stability window (and thus solid electrolyte interphase formation), and the composition of the electrochemical double layer1,2,3. However, elucidation of this structure at an atomic level of detail has been challenging to accomplish via a purely experimental approach. Here we combine machine-learning-enabled atomistic simulations4,5,6,7,8,9,10,11,12,13,14,15,16, nuclear magnetic resonance spectroscopy, electrochemical data3,17,18,19,20 and quantum-chemical calculations to reveal previously unstudied multi-Li+ complexes without bound anions that are uniquely facile for reduction. This insight explains the success of empirically chosen ethylene-carbonate-containing solvent mixtures and provides a foundation for the rational design of improved electrolytes. Furthermore, our machine-learning force-field-based lithium-ion-battery electrolyte simulations accurately reproduce a wide range of condensed-phase experiments3,21,22,23,24, despite being parameterized to only quantum-chemical gas-phase cluster calculations, and hence provide a compelling demonstration that machine-learning force-field-based models developed from first principles can robustly represent a complex chemical system to atomic resolution.
Batteries, Computational chemistry, Atomistic models
Global conservation area coverage substantially exceeds current estimates
Original Paper | Conservation biology | 2026-10-13 20:00 EDT
Helen M. K. O’Neill, Joe Beeken, Heather C. Bingham, Rachel E. Golden Kroner, Yifan He, Jessica L. Stewart, Adil Mohamed Ali, Javier Beltran, Joseph W. Bull, Susan Canney, Nuwanthika Dharmaratne, Cristina Eghenter, James A. Fitzsimons, Samantha Hill, Clinton N. Jenkins, Cindy Julianty, Yolanda M. Leon, John MacKinnon, Alphonce B. Mallya, Daniel Marnewick, Golo Maurer, Mayra Milkovic, Ameer Awad Mohammed, Yuvenal Pantaleo, Blair Parsons, Fábio Ricarte, Ryan Richards, Sushma Shrestha Sangat, Dewi Puspitasari Sutejo, Mridhu Tandon, Corrado Teofili, Kasmita Widodo, Jens Wunderlich, Steffen Zuther, Zoe G. Davies, Robert J. Smith
Conservation areas are critical for tackling the global environmental crisis1. These sites are reported as covering 18.5% of the terrestrial realm2 and governments have committed through Global Biodiversity Framework Target 3 to increase this to at least 30% by 2030 (ref. 3). There are concerns that this potential near-doubling of conservation area coverage will negatively affect vulnerable people and over-stretch conservation resources4. However, nationally available datasets indicate that more conservation areas exist than are reflected in global figures5,6,7. We evaluated progress towards the area component of Target 3 using a globally representative sample across 25 countries and territories that incorporated these national datasets8. Extrapolating from this sample, we show that conservation areas likely already cover 26.81% of the terrestrial realm. We may be much closer to achieving 30% terrestrial coverage than previously thought. However, we also show that the extra land does not substantially address gaps in ecological representativeness, indicating that solely meeting the area component of Target 3 will do little to solve continuing global biodiversity loss. More focus and resources are needed to achieve the other components of the target, using a more strategic and inclusive approach to fill present gaps and produce equitable and effective conservation area networks.
Conservation biology, Biodiversity
Engineered TYK2 dependence enables myeloid-selective IL-10 receptor agonism
Original Paper | Antibody therapy | 2026-10-13 20:00 EDT
D. Alejandro Canaria, Trang T. T. Nguyen, Huang Huang, Hui Xu, Lili Yue, Yongyao Fu, Hoa Truong, Kerul Patel, Weimei Xing, Jayamary Divya Ravichandar, Cong Xing, Aron L. Martin, George Delidakis, Sylvia Wong, Andrew Pae, Yu Yu, Ramsay Macdonald, Zhiyu Huang, Meagan C. Main, Amanali Rodriguez, Xiaoli Lin, Maria L. Mouchess, Magdeleine Hung, Ellen M. McGlinchey, Lei Chen, Nicole Schirle Oakdale, Brian Carr, Megan L. Koleske, Chingwei V. Lee, Chen Chen, Tangsheng Yi
Interleukin-10 (IL-10) is a central anti-inflammatory cytokine that suppresses immune responses in myeloid cells but can also activate T cells, limiting its therapeutic use in chronic inflammatory diseases owing to narrow efficacy windows and dose-limiting toxicities1,2,3,4,5. Here we show that myeloid and T cells differ in their dependence on JAK-family kinase pairing for IL-10 signalling and function. We took advantage of this differential kinase dependence to engineer a tetravalent nanobody-based myeloid-selective IL-10 receptor agonist (msIL-10R agonist) that fully recapitulates IL-10’s potent suppression of monocytes, macrophages and dendritic cells while avoiding stimulation of T cells. Cryo-electron microscopy structural analysis reveals a distinct receptor cross-linking geometry of the msIL-10R agonist compared with native IL-10 family cytokines. This tetravalent architecture renders signalling strictly TYK2-dependent and highly sensitive to IL-10Rα and IL-10Rβ receptor abundance, thereby conferring selective activity in myeloid cells. This msIL-10R agonist reduces inflammation in humanized mouse models of lipopolysaccharide challenge, delayed-type hypersensitivity and colitis. A humanized version exhibits IgG-like pharmacokinetics, sustained receptor occupancy and durable myeloid suppression up to 30 days without T cell activation or haematological toxicities in non-human primates. These findings establish a geometry-based strategy for achieving cell-type-selective cytokine signalling and identify the msIL-10R agonist as a therapeutic candidate for myeloid-driven inflammatory diseases, including inflammatory bowel diseases.
Antibody therapy, Autoimmune diseases, Interleukins, Inflammatory bowel disease, Cryoelectron microscopy
Elp1 is required for myeloid differentiation and brain repopulation
Original Paper | Neuroimmunology | 2026-10-13 20:00 EDT
Marius Marc-Daniel Mader, Wanhua Li, Alexa Scavetti, Yongjin Yoo, Gernot Neumayer, Katie Han, Yohei Shibuya, Michael Haney, Tony Wyss-Coray, Lynn George, Frances Lefcort, Michael Bassik, Hiromitsu Nakauchi, Adam C. Wilkinson, Marius Wernig
Haematopoietic stem and progenitor cell (HSPC) transplantation-mediated replacement of microglia–the reconstitution of the central nervous system microglial niche with donor-derived myeloid cells–represents a promising strategy for brain cell therapies1,2,3,4,5,6,7. However, the cell-intrinsic molecular regulators of HSPC-derived myeloid lineage commitment in the brain have remained largely uncharacterized. This is partially because the scarcity of primary HSPCs has rendered large-scale genetic interrogation intractable. Here we explored whether ex vivo expansion of primary cultured HSPCs (cHSPCs) enables unbiased genetic interrogation of haematopoietic differentiation. We established that cHSPCs can be genetically manipulated and readily differentiate into myeloid cells and repopulate microglia niches of the brain after transplantation. Moreover, primary neonatal astrocytes contained strong signals to induce myeloid specification of cHSPCs in vitro. To identify genes that regulate glia-induced myeloid differentiation, we successfully screened around 20,000 individual genetic perturbations and characterized genes involved in the regulation of cell signalling, cell cycle, mitochondrial function and protein translation. Among these genes was elongator acetyltransferase complex subunit 1 (Elp1), which suppressed the unfolded protein response during myeloid specification and was essential for the generation but not maintenance of myeloid cells. Our work establishes a platform to investigate the molecular mechanisms of brain myeloid biology.
Neuroimmunology, Haematopoietic stem cells, Bone marrow transplantation, Differentiation, Stem-cell research
Modelling mouse embryogenesis from chemically induced totipotent stem cells
Original Paper | Totipotent stem cells | 2026-10-13 20:00 EDT
Hua Wu, Yanyan Hu, Hanzhi Yu, Nana Huang, Lu Shi, Menghan Gao, Xinghan Du, Xue Lu, Yuxia Zhang, Xiya Sun, Xiaoqing Xu, Zhimin Liu, Junsong Yuan, Wei Zhou, Qiliang Shao, Dan Wang, Yangyu Zhao, Tianhua Ma, Sheng Ding
The ability to faithfully initiate embryogenesis from a single, induced non-germline cell type, akin to the totipotent blastomeres, remains a considerable challenge in developmental and synthetic biology1,2,3,4,5,6,7,8,9,10,11,12,13,14. Here we established conditions that enable the continuous ex utero development of mouse embryo models (EMs), starting solely from the chemically induced totipotent-like stem cells (ciTotiSCs)15 and spanning the pre-implantation morula, blastocysts and post-gastrulation stages with both embryonic and extraembryonic compartments. These ciTotiSCs self-organized into blastocyst-like structures that closely resembled natural blastocysts in both morphology and lineage segregation. The resulting ciTotiSC-derived EMs (ciToti-EMs) successfully progressed through key developmental milestones, including gastrulation, embryonic axis formation, haematopoiesis and early organogenesis, closely resembling embryonic day 8.5 (E8.5) natural embryos (NEs). Furthermore, extended culture led to the development of functional cardiac tissues in ciToti-EMs, highly comparable to those of E10.5 NEs. These findings demonstrate an extraordinary ability of a single induced cell type, ciTotiSCs, to autonomously recapitulate the complete spectrum of early mouse embryogenesis. Our ciToti-EM system provides a powerful model for investigating mammalian embryonic development and opens new avenues for creating multicellular organisms from non-germline cells.
Totipotent stem cells, Embryogenesis, Embryonic stem cells
Competing mechanisms toughen bcc binary and medium-entropy alloys at 20 K
Original Paper | Structural materials | 2026-10-13 20:00 EDT
David H. Cook, Xiaoyu Chen, Michael O’Leary, Satish Rao, Wenqing Wang, Calvin H. Belcher, Madelyn Payne, Pedro Borges, Tung Lik Lee, Arun Devaraj, Mark Asta, Enrique J. Lavernia, Diran Apelian, Andrew M. Minor, Dong Liu, Punit Kumar, Robert O. Ritchie
Plastic deformation in body-centred cubic (bcc) metals and alloys is conventionally mediated by screw dislocations. Their temperature-sensitive motion is attributed to a steep rise in strength with decreasing temperature that constricts plastic zones at crack tips, leading to a ductile-to-brittle transition1. Here we evaluated the mechanical properties of group IV-V bcc refractory alloys with similar electronic structures at 20 K and found that these materials instead exhibit a plateau in tensile yield strength and fracture toughness as a function of temperature, with no apparent ductile-to-brittle transition. This behaviour arises from the global activation of twinning and an ω-phase transformation, which nucleate dislocations at interfaces before global dislocation motion. The initial mechanism is temperature insensitive and controls yielding, thereby preventing a crack-tip plastic zone from constricting with decreasing temperature.
Structural materials, Mechanical engineering
Parity-dependent coupling of molecular spin chains to a superconductor
Original Paper | Magnetic properties and materials | 2026-10-13 20:00 EDT
Katerina Vaxevani, Jon Ortuzar, Stefano Trivini, Georg Monninger, Dongfei Wang, Manuel Vilas-Varela, Lucía Gómez-Rodrigo, Diego Peña, Jose Ignacio Pascual
Collective behaviour in quantum materials can produce excitations carrying only a fraction of the quantum numbers of their constituents. A notable case occurs in chains of spin-1 units1, in which a topological gap protects the interior of the chain, whereas spin-1/2 states, half the spin of the units that form it, emerge at the ends2. In short chains, these fractional edge spins couple to each other and their topological protection makes them attractive for hybrid spin-superconductor devices. Whether such fractionalization survives the proximity of a superconducting condensate, however, remains an open question. Here we grow molecular Haldane chains of antiferromagnetically coupled spin-1 triangulene units on a proximitized Au(111)/Nb(110) surface and resolve a parity-dependent coupling of their spin-1/2 edge states to the superconductor by scanning tunnelling spectroscopy. Odd-length chains host Yu-Shiba-Rusinov (YSR) bound states inside the superconducting gap, originating from a global S = 1 ground state, whereas even-length chains form an S = 0 ground state decoupled from the superconductor. A two-site model attributes this alternation to the sign and strength of inter-edge interactions, independently confirmed by extra-gap spin excitations in tunnelling spectra. Many-body spin excitations of the S = 1 chain are also detected, decoupled from the superconductor by the much larger Haldane gap. The length-tunable coupling of the edge spins to superconductors opens a route towards molecular spin qubits based on π-conjugated carbon architectures.
Magnetic properties and materials, Quantum metrology, Superconducting properties and materials, Surfaces, interfaces and thin films
Capillary-selective vasodilation through myosin inhibition halts ischaemic cascades
Original Paper | Target identification | 2026-10-13 20:00 EDT
Máté Pénzes, Máté Winternitz, Ádám I. Horváth, Svetlana Mastitskaya, Usman Awan, Tamás Szimler, Camille Glaser, Carlos Kikuti, Marie Juillé, Leila Heidsieck, Anna Á. Rauscher, Tímea Bálint, Dávid Nagy, Tamás Radovits, Alex Ali Sayour, C. Michael Gibson, Anne Houdusse, Máté Gyimesi, András Málnási-Csizmadia
In acute myocardial infarction and acute kidney injury, capillary no-reflow denotes that capillary blood flow is still blocked despite successful arterial reperfusion. This is associated with substantially increased mortality and reinfarction risk; nevertheless, no targeted therapy exists so far1,2. Because capillary no-reflow is driven by smooth muscle myosin-mediated hypercontraction of capillary pericytes, we developed R(+)2501, a myosin-specific and capillary-selective vasodilator. In reperfused animal models of acute myocardial infarction and acute kidney injury, direct in vivo imaging showed that R(+)2501 rapidly restored capillary flow, an effect sustained even after rapid drug clearance. Ex vivo experiments confirmed reversal of pericyte constriction directly. Restoration of capillary blood flow, together with clearance of trapped neutrophils, linked resolution of capillary no-reflow to attenuation of an early driver of reperfusion injury. R(+)2501 enhanced capillary perfusion while preserving coronary autoregulation and systemic haemodynamics, and markedly improved survival during acute reperfusion. We further found that acute myocardial infarction induced renal capillary no-reflow, which was reversed by R(+)2501, suggesting that capillary no-reflow contributes to the pathophysiology of cardiorenal syndrome type I. These findings establish pericyte-targeted smooth muscle myosin inhibition as a therapeutic strategy to restore microvascular perfusion and halt the ischaemic cascade across organs, while defining a specific physiological role for capillaries and pericytes in circulatory regulation.
Target identification, Mechanism of action, X-ray crystallography
Evaluating space-based methane detection through a one-year blind test
Original Paper | Climate-change mitigation | 2026-10-13 20:00 EDT
Frances E. Reuland, Taylor Adams, Evan D. Sherwin, Sahar H. El Abbadi, Eric A. Kort, Adam R. Brandt
Space-based remote sensing allows detection and monitoring of large, concentrated methane sources worldwide1. However, independent evaluation of instruments and algorithms is limited, and new satellites and artificial intelligence techniques have not been tested under controlled, single-blind conditions2. Here we conduct a year-long, single-blind test involving 746 events: 481 methane releases of 9.5-1,183.7 kg h-1 and 265 blank controls. We released metered methane quantities in Arizona, USA, coinciding with overpasses from 12 government, commercial and non-profit satellites. Fifteen analysis teams from nine countries generated more than 2,250 estimates, making this, to our knowledge, the largest controlled test so far and one of the first evaluations of the instruments EMIT, Tanager-1 (Carbon Mapper) and GHOSt. Performance is heterogeneous: ‘built-for-purpose’ instruments designed to target methane demonstrate excellent detection performance (92-100% true positive rate, 0-11% false positive rate) and quantification accuracy (slope 0.83-1.00, 44% mean absolute percentage error). Instruments repurposed for methane sensing perform more variably (detection rates 62-88%, 46% mean absolute percentage error); still, many demonstrate significant skill. Broad land scanners detect poorly at tested rates but have consistent global coverage and historical archives, motivating additional work. Artificial intelligence-based methods show promise, but caution is warranted; 79% of false positives emerge from these methods. Ground-measured cloud cover >20% degraded performance across systems, raising concerns for use in some locations. Our findings show that satellite-based measurements can achieve accurate detection and quantification of methane point sources when the source location is approximately known.
Climate-change mitigation, Atmospheric science, Environmental impact
De novo design of cysteine proteases
Original Paper | Proteases | 2026-10-13 20:00 EDT
Hojae Choi, Magnus S. Bauer, Brian Coventry, Preetham Venkatesh, Anqi Chen, Donghyo Kim, Asim K. Bera, Alex Kang, Hannah Nguyen, Shayan Sadre, Justin Decarreau, Emily Joyce, Bhanumathi Shankaran, Tuscan Rock Thompson, Gabriel Greenstein, Kieran Didi, Lars L. Schaaf, Jacob Merle Gershon, Alexander F. Shida, Gyu Rie Lee, Donald Hilvert, Samuel J. Pellock, David Baker
Despite advances in de novo enzyme design, success has been largely limited to low-energy-barrier model reactions. Amide bonds such as those linking amino acids along the peptide backbone are stable for hundreds of years in neutral aqueous solution because of the high energy barrier to hydrolysis1. Here we describe the de novo design of enzymes that use an activated cysteine nucleophile to hydrolyse the polypeptide backbone in a sequence-dependent manner, with a success rate of 13/69 = 19% and rate enhancements over the background reaction (kcat/kuncat) of up to 3 × 107. The designed proteases have folds that are very different from proteases in nature (TM score < 0.50), and six crystal structures are very close to the design models (Cα root mean squared deviation of <1.2 Å), highlighting the capacity for generalization and the accuracy of the design methodology. Experimental and computational analyses suggest that the remaining gap in activity to the most active native cysteine proteases arises from imperfections in active-site preorganization and substrate positioning. The designed proteases efficiently cleave their targets in mammalian cells, opening the door to a wide range of synthetic biology applications.
Proteases, Protein design
Computational design of metalloproteases
Original Paper | Protein design | 2026-10-13 20:00 EDT
Anqi Chen, Kejia Wu, Hojae Choi, Preetham Venkatesh, Samuel J. Pellock, Nikita Hanikel, Hojeong shin, Declan Evans, Kieran Didi, Lars L. Schaaf, Cristina Díaz-Perlas, Brian Coventry, Donghyo Kim, Seth M. Woodbury, Pengfei Ji, Shingo Honda, Asim K. Bera, Hannah Nguyen, Alex Kang, Yanqing Wang, Xinting Li, Stacey Gerben, Lemuel Chang, Xiao Yan, Benjamí Oller-Salvia, Anthony A. Hyman, Donald Hilvert, David Baker
De novo design of enzymes that cleave amide bonds represents a major challenge1,2. Here we use RFdiffusion methods3,4 to de novo design proteins with water-activating zinc-based active sites adjacent to a peptide substrate binding pocket. Of 135 designs tested, 36% catalyse cleavage of their cognate peptide substrates at the targeted scissile bond. The best design accelerates peptide-bond hydrolysis by more than 108-fold relative to the uncatalysed reaction; four substitutions increase this acceleration to more than 1010-fold by improving active-site preorganization5. We use this approach to design metalloproteases that selectively cleave the human disease-associated proteins TDP-43, amyloid-β and serum amyloid A, with rate enhancements of up to 109-fold. We further design caged cytokines and receptor antagonists that are selectively activated by the designed proteases, enabling bioorthogonal control of cell state. Thus, de novo design can yield highly active, programmable proteases with applications in therapeutics, biotechnology and bioremediation.
Protein design, Proteases
Divergent genomic evolution in astrocytomas and oligodendrogliomas
Original Paper | CNS cancer | 2026-10-13 20:00 EDT
Tamrin Chowdhury, C. Mircea S. Tesileanu, Emre Kocakavuk, Kevin C. Johnson, Joo Ho Lee, Zeynep Erson-Omay, Chaewon Heo, Kenneth Aldape, Samirkumar B. Amin, Kevin J. Anderson, David M. Ashley, Floris P. Barthel, Jill S. Barnholtz-Sloan, Daniel J. Brat, Andrew R. Brodbelt, Ana Valeria Castro, Elizabeth B. Claus, Jennifer M. Connelly, Joseph F. Costello, Indrani Datta, Carol Elliott, Gaetano Finocchiaro, Pim J. French, Hui K. Gan, Luciano Garofano, Padmaja L. Ghospurkar, Anna Golebiewska, Pranav S. Gundla, Beth Hermes, Chibo Hong, Youri Hoogstrate, Craig Horbinski, Jason T. Huse, Antonio Iavarone, Cihat Karadag, Mustafa Khasraw, Mathilde C. M. Kouwenhoven, Peter S. LaViolette, Kay Li, Allison Lowman, Katy McCortney, Hyo-Eun Moon, Nader Sanai, MacLean P. Nasrallah, H. K. Ng, D. Ryan Ormond, Bethany Kwan, Marta Padovan, Sun Ha Paek, Laila M. Poisson, Sushant Puri, Erica Shen, Shwetal Mehta, Andrew E. Sloan, Wies R. Vallentgoed, Erwin G. Van Meir, Rachael Vaubel, Taylor E. Wade, Annemiek M. E. Walenkamp, Colin Watts, Tobias Weiss, Michael Weller, Pieter Wesseling, Kerryn Westcott, Bart A. Westerman, Gordon Y. Ye, W. K. Alfred Yung, Frederick S. Varn, Roel G. W. Verhaak
Astrocytomas and oligodendrogliomas are isocitrate dehydrogenase (IDH)-mutant gliomas that most commonly arise in adults under the age of 50 and exhibit variable responses to treatment1,2,3. To understand the genetic drivers of disease progression, here we used whole-genome and whole-exome sequencing to characterize longitudinally collected tumour specimens from 183 patients with IDH-mutant glioma. Samples were collected through the Glioma Longitudinal Analysis (GLASS) Consortium4. Most primary surgery samples were classified as grade 2 on the basis of histology (73% for astrocytomas and 93% for oligodendrogliomas). We validated known genomic markers of tumour progression, including hypermutation and homozygous deletion of CDKN2A or CDKN2B (hereafter, CDKN2A/B)5, and discovered genetic alterations that distinguish between the evolutionary trajectories of astrocytomas and those of oligodendrogliomas. Mutations in phosphatidylinositol 3-kinase (PI3K) and NOTCH1 were newly acquired in recurrent oligodendrogliomas, regardless of treatment, and were associated with an increased tumour mutational burden. In recurrent astrocytomas, however, again irrespective of treatment, acquired focal oncogene amplifications and CDKN2A/B homozygous deletions were associated with an increase in chromosomal imbalances, which converged with markers of chromosomal instability such as chromothripsis and whole-genome doubling. In both types of IDH-mutant glioma, we observed a convergence of acquired alterations, genome-wide changes and worse patient outcomes, suggesting that treatment-refractory clones were being selected. Treatment with temozolomide was associated with the mutational signatures SBS11 and SBS119 in both tumour types, whereas the radiotherapy-associated ID8 signature increased in astrocytomas specifically. We show that the genomes of oligodendrogliomas and astrocytomas adapt to the selective pressures of tumour progression and treatment in distinct ways, suggesting that oligodendrogliomas and astrocytomas differ in their responses to treatment-induced DNA damage.
CNS cancer, Tumour heterogeneity, Biomarkers
Rh3+ stabilized in KRh@MFI catalyses regioselective hydroformylation
Original Paper | Chemistry | 2026-10-13 20:00 EDT
Minjie Zhao, Reisel Millán, Alina Skorynina, Laura Simonelli, Miguel Lopez Haro, José Juan Calvino, Patricia Concepción, Avelino Corma
Hydroformylation has been a cornerstone of industrial organometallic catalysis, with regioselectivity being a critical aspect in this process1,2. Present industrial systems use homogeneous Rh-based catalysts with expensive and toxic phosphine-containing ligands, underscoring the need to develop alternative heterogeneous catalysts that could compete with the actual homogeneous ones3. In this direction, atomically dispersed Rh catalysts have been proposed as promising candidates for hydroformylation4,5. However, achieving high regioselectivity at high conversion is still a big challenge. Here subnanometre Rh2O3 clusters are confined inside the channels of the MFI zeolite, which under reaction conditions disrupt into isolated Rh3+ and Rh+ species. Density functional theory (DFT) investigations combined with spectroscopic and catalytic studies demonstrate that Rh3+-mediated hydroformylation is energetically plausibly similar to Rh+, with Rh3+ being intrinsically more selective for hydroformylation and less selective for double-bond isomerization than Rh+. In the coexistence of both Rh3+ and Rh+ species, we demonstrate the possibility to selectively inhibit Rh+ sites through the addition of N-containing molecules such as N-methylpyrrolidine (MP) or 1-methyl-2-pyrrolidone (NMP), which preferentially coordinate to Rh+ inside MFI zeolite channel, thereby suppressing its isomerization function while leaving Rh3+ sites catalytically accessible. This strategy results in a notable enhancement of regioselectivity, with a state-of-the-art reported highest linear to branched aldehydes (l/b) ratio of 817 with 96% undecanal selectivity at 99.8% 1-decene conversion, using NMP as additive.
Chemistry, Catalysis
Targeted stimulation of motor cortex ensembles drives learned movements
Original Paper | Motor cortex | 2026-10-13 20:00 EDT
Qiyu Chen, An Wu, Bin Yu, Soyoung Chae, Zijing Tan, Assaf Ramot, Johnatan Aljadeff, Takaki Komiyama
During the execution of learned motor skills, the neural population in layer 2/3 (L2/3) of primary motor cortex (M1) expresses a reproducible spatiotemporal activity pattern1. It is debated whether M1 actively participates in generating this learned pattern and whether this pattern causally drives the learned movement2,3,4,5. Here we combined in vivo two-photon calcium imaging and holographic optogenetic stimulation of functionally defined M1 L2/3 ensembles in mice performing a skilled lever-pressing task. Brief synchronous stimulation of about 20 neurons whose activity onset precedes voluntary movement onset induced movements resembling the learned movement, while producing activity patterns in other M1 neurons resembling the learned activity. Moreover, trial-by-trial variability of optogenetically triggered population activity correlated with variability in the induced movements. These variabilities were predicted by the initial state of M1 activity preceding stimulation. In some trials, stimulation induced the learned activity without inducing movements, indicating that the learned activity is not simply a reflection of movements but can arise internally. Stimulation failed to generate movements or learned activity in task-disengaged mice. Stimulation of neurons whose activity followed movement onsets failed to induce the learned movement in task-engaged mice. Together, the learned activity in M1 L2/3 can be generated when M1 is prepared at the optimal initial state and receives precise triggering inputs, supporting the active role of M1 in generating learned activity and learned movements.
Motor cortex, Neural circuits
Artificial intelligence-enabled clinical phenotyping of human brown fat
Original Paper | Translational research | 2026-10-13 20:00 EDT
Nicolás Gómez-Banoy, Jorge A. Barrero, Luiza Rachel Pinheiro de Carvalho, Caroline S. Jiang, Tara Doma Lama, Nakul Karandikar, Mascha Koenen, Tiffany Lam, Kaja Plucińska, Ksenia Morozova, Stephanie Chahwan, Gustavo Barraza, Burcin Agridag Ucpinar, Jennifer E. Liu, Rohit Sharma, Daniel Lafontaine, Heiko Schöder, Paul Cohen
Adipose tissue has a central role in systemic energy balance and the pathogenesis of obesity and its sequelae1,2. In contrast to white adipose tissue, brown adipose tissue (BAT) uses energy to produce heat3. Detectable BAT in humans is associated with decreased prevalence of cardiometabolic diseases4. However, the complete spectrum of health conditions associated with BAT remains unknown, and high-throughput methods to quantify BAT activity in humans are lacking5,6. Here we leveraged big data and artificial intelligence to systematically define the clinical impact of BAT in a cohort of 101,243 patients from a large cancer centre. Our unbiased analyses revealed that, across all diagnoses, cardiovascular and psychiatric diseases were less prevalent in people with BAT. Using a machine learning approach, we semi-automatically quantified BAT activity in approximately 8,700 patients and demonstrated that higher BAT activity, especially in the axillary depot, is associated with lower odds of cardiometabolic diseases and healthier white fat distribution. People with BAT also exhibited more favourable glycaemic parameters, lipid profiles, inflammatory markers and echocardiographic indices. Analysis of medication usage demonstrated that angiotensin receptor blocker use was positively associated with BAT presence. As proof of concept, we showed that the angiotensin receptor blocker losartan increased brown adipocyte activity and whole-body energy expenditure. Altogether, our studies harnessing artificial intelligence and big data identify new clinical phenotypes linked to BAT and serve as a platform for drug repurposing to activate this tissue in humans.
Translational research, Preclinical research
Early tetrapod neck mobility modelled using an extant analogue
Original Paper | Palaeontology | 2026-10-13 20:00 EDT
Dana E. Korneisel, Cassandra M. Donatelli, Linfang Han, Thomas A. Stewart, Andrew L. Traynor, Benjamin K. A. Otoo, Marcos Martinez, Tetsuto Miyashita, Emily M. Standen, Hillary C. Maddin
Tetrapods arose from lobe-finned fishes with a notochord-dominated axial column1,2,3. During this transition, the skull became separated from the shoulder girdle4,5,6, giving rise to a neck region. This head-shoulder separation has generated hypotheses suggesting that neck mobility increased during the origin of tetrapods, facilitating the ecological transition towards more terrestrial habitats4,5,7,8,9. However, incompletely co-ossified vertebral components10 have posed a challenge to modelling the mobility of these early tetrapod necks. Here we used material tests on the similarly configured axial columns of sturgeon to predict the capacities of the tetrapod neck region for lateral flexion, extension and rotation across the tetrapod stem. Our model indicates that the soft tissue-dominated axial column was surprisingly rigid, despite lacking co-ossified vertebral components. We estimate that most stem tetrapods could move their heads less than 6° laterally and less than 3° dorsally but could not rotate them. Notably, mobility did not shift in conjunction with the head-shoulder separation that occurred between the origin of tristichopterids (represented by Eusthenopteron) and that of more crownward stem tetrapods. Therefore, mobility in the tetrapod neck did not serve as a functional driver of head-shoulder separation. Instead, forelimb-driven locomotion, implicated in early tetrapods11,12,13,14, provides a better functional explanation for the head-shoulder separation.
Palaeontology, Biological techniques
Intrinsic physicochemical activity at microplastic-water interfaces
Original Paper | Physical chemistry | 2026-10-13 20:00 EDT
Naixin Qian, Ruoqi Zhao, Kwing Yeung Chan, Vinh Gia Vuong, Xin Gao, Zhilun Zhao, R. Allen LaCour, Yifan Dai, Phoebe A. Stapleton, Beizhan Yan, Teresa Head-Gordon, Wei Min
Plastics have become an integral part of our modern society, largely because they are generally regarded as chemically inert under normal circumstances. However, plastics fragmented into microplastics (less than 5 mm in size) have recently raised significant public concerns, and have been detected widely across ecosystems and human tissues with increasing environmental and health risks1,2,3,4,5. Here we show that commodity microplastics exhibit intrinsic physicochemical activity in water, manifested by the spontaneous generation of reactive oxygen species that increases with interfacial hydrophobicity and strongly correlates with interfacial electrostatics. Ab initio calculations support these observations and reveal that hydroxide oxidation becomes energetically more favourable at increasingly hydrophobic microplastic-water interfaces through the combined effects of partial solvation and electrostatics. These interfacial properties and the resulting oxidative chemistry have direct implications for biomolecular adsorption, protein aggregation, and even cellular damage. Together, our findings challenge the prevailing paradigm of plastic inertness, identify a possibly overlooked mechanism for the detrimental effects of microplastics on health and the environment, and contribute to a fundamental understanding of the structure-activity relationship of interfacial water, which may inform the design of safer and more sustainable plastic materials.
Physical chemistry, Environmental chemistry, Surface chemistry
Hidden reaction pathways inform additive engineering for perovskite LEDs
Original Paper | Organic LEDs | 2026-10-13 20:00 EDT
Sung-Doo Baek, Yu-Ting Yang, Pengfei Wu, Hanjun Yang, Mohammad Ali, Hui Taou Kok, Xiyu Luo, Wenhao Shao, Hyuntae Choi, Jeong Hui Kim, L. Jay Guo, Libai Huang, Barry P. Rand, Letian Dou
Perovskite light-emitting diodes (PeLEDs) have emerged as a promising class of solution-processed light-emitting devices, combining high efficiency with facile fabrication1,2,3,4,5. Amino-acid-based molecular additives are widely used to regulate crystallization and suppress defects in perovskite thin films6,7,8, yet these molecules are chemically reactive in precursor solutions, in which their transformations and products remain poorly understood. Here we resolve and control the hidden solution-phase chemistry of a ubiquitous additive, 5-aminovaleric acid (5AVA), whose solution-phase reactivity has remained unclear6,9,10,11,12,13,14,15. We show that 5AVA undergoes competing in situ reactions during precursor preconditioning, yielding two chemically and functionally distinct products: a beneficial organoamidinium zwitterion and a detrimental Lewis-base lactam. By explaining this reaction dichotomy and establishing targeted reaction-pathway control, we selectively use the beneficial species. Direct synthesis and incorporation of the purified zwitterion decouple its intrinsic passivation function from confounding by-products, yielding perovskite films with a near-unity mean peak photoluminescence quantum yield (PLQY) of 97.2% and PeLEDs with a champion external quantum efficiency (EQE) of 37.1%, alongside a mean peak EQE of 32.8%. Finally, we demonstrate that this reaction-pathway control concept can be extended to further additive chemistries and emission colours, highlighting its potential as a chemistry-driven strategy for rational additive design in PeLEDs.
Organic LEDs, Inorganic LEDs, Electronic materials
Clasping folds enable superior elastic strength of graphene films
Original Paper | Mechanical and structural properties and devices | 2026-10-13 20:00 EDT
Lidan Wang, Yangchao Liao, Jingjie Huang, Chenwei Shen, Lu Chen, Xing Li, Degong Ding, Mingtao Zhang, Li Peng, Kaiwen Li, Peng Li, Yingjun Liu, Zhen Xu, Kai Pang, Zhiping Xu, Chao Gao
Two-dimensional graphene sheets show strong potential for use in fabrication of macroscopic films, as they have exceptional mechanical properties owing to their in-plane strength1,2,3,4,5,6. Improvements in the stacking order of flat two-dimensional sheets have led to corresponding improvements in the strength and toughness of such films7,8,9,10,11. In addition, modulation of the spatial conformation of individual units has enabled the development of benchmark materials with superior properties12,13; however, this has remained elusive in the case of two-dimensional sheets. Here we report a strategy for preparation of graphene films with a combination of high strength (2.9 GPa), toughness (84.5 MJ m-3) and elastic strain (5%). We attribute these performance gains to a fold-clasping lamellar structure achieved by modular assembly of surface-folded multilayer graphene oxide flakes. We identify a pull-to-push transition of force chain topology and propose a shear-lock stress transfer strategy in the fold-clasping lamellar graphene film that enables advances in mechanical properties. This work demonstrates the modular design of spatial conformation of two-dimensional flakes on a large scale and further improves the performance of macroscopic films for potential applications in lightweight structural components.
Mechanical and structural properties and devices, Mechanical properties
Wave coarsening drives time crystallization in mechatronic metamaterials
Original Paper | Nonlinear phenomena | 2026-10-13 20:00 EDT
Jonas Veenstra, Jack Binysh, Vito Seinen, Roger Solé Borràs, Rutger Naber, Damien Robledo-Poisson, Andres Hunt, Wim van Saarloos, Anton Souslov, Corentin Coulais
When metals are magnetized1, emulsions phase separate2, or galaxies cluster3, domain walls and patterns form and irremediably coarsen over time. This coarsening is universally driven by diffusive relaxation towards equilibrium. Here we discover a vibrational counterpart–wave coarsening–in active elastic media4,5,6,7,8,9,10,11,12,13: vibrations emerge and spontaneously grow in wavelength, period and amplitude, before a globally synchronized state called a time crystal14,15,16,17 forms. We observe wave coarsening in one- and two-dimensional mechatronic metamaterials and capture its dynamical scaling. We further arrest the process by breaking momentum conservation and reveal a far-from-equilibrium nonlinear analogue to chiral topological edge modes<a data-test=”citation-ref” data-track=”click” data-track-action=”reference anchor” data-track-label=”link” href=”https://www.nature.com/articles/s41586-026-11163-6#ref-CR18“ id=”ref-link-section-d21203258e484” title=”Haldane, F. D. Model for a quantum Hall effect without Landau levels: condensed-matter realization of the “parity anomaly”. Phys. Rev. Lett. 61, 2015-2018 (1988).”>18,19,20,21,22,23,24. Our results open new questions about the transient physics of systems with non-potential interactions15,25,26,27,28 and suggest an organizing principle for nonlinear waves in acoustics29,30, optomechanics31,32, living matter6,33 and soft robotics9.
Nonlinear phenomena, Mechanical engineering, Mechanical properties
Sexual dimorphism in epidermal stem cell dynamics
Original Paper | Skin stem cells | 2026-10-13 20:00 EDT
Dan Engelman, Joel Hochstetter, Anaïs Bauduin, Sagar Patil, Marta Valenti, Yura Song, Qiuyu Lian, Annagiada Toniolo, Mohammad Ghiasloo, Nordin Bansaccal, Anne-Lise Delaunois, Mélanie Liagre, Michele De Luca, Esther Hoste, Laura De Rosa, Yulia Shwartz, Benjamin D. Simons, Cédric Blanpain
The epidermis is a stratified epithelium comprising proliferative basal cells and differentiated suprabasal cells that are continuously renewed throughout life. Conflicting theories have been proposed regarding the heterogeneity of the basal cell layer, with some studies proposing that all proliferative cells have self-renewal potential during homeostasis1,2,3,4,5. Meanwhile, others posit a model in which stem cell differentiation occurs through an intermediate transit-amplifying-like progenitor state with strictly limited proliferative potential6,7,8,9,10. Here, to determine the heterogeneity and pattern of cell fate, we performed intravital time-lapse imaging to track the fate of lineage-labelled cells in the skin interfollicular epidermis. Results from quantitative analyses of clonal dynamics support a two-compartment model of epidermal homeostasis, whereby basal cells are organized in a stem cell-transit-amplifying cell hierarchy. Critical to these conclusions was the discovery of sexual dimorphism in epidermal fate, with female mice showing a highly synchronized pattern of cell division, differentiation and delamination that contributes to accelerated wound healing. Single-cell RNA sequencing, transcriptional profiling and clonal analyses of castrated mice revealed that male sex hormones promote stem cell differentiation and delamination. In summary, our study provides insight into the functional identity of the stem cell population and identifies sex-specific differences in the regulation of epidermal stem cells and transit-amplifying cell fate.
Skin stem cells, Stem-cell differentiation, Biophysics
Interhemispheric monsoon dynamics over the past 450,000 years
Original Paper | Palaeoclimate | 2026-10-13 20:00 EDT
E. J. Olson, D. P. Gillikin, D. Parmenter, S. Burns, A. Verheyden, O. Miyawaki, M. Vuille, L. F. Piccirillo, R. Castro, G. Yurivilca, R. L. Edwards, D. T. Rodbell
The global monsoon system provides freshwater to much of Earth’s biota, including its human population1. The Milankovitch theory predicts changes in Earth’s solar insolation over geologic time, and these variations are expected to result in changes to the global monsoon2. Internal climate forcings, such as ice cover and sea surface temperatures, may also affect the system. However, few records of monsoon variability in the Southern Hemisphere over glacial-interglacial cycles exist to test our understanding of the factors that drive variations in the global monsoon. Here we show that monsoons in both the Southern and Northern Hemispheres vary with Milankovitch forcing, and with internal boundary conditions over the past 450,000 years. We present a record of South American Summer Monsoon (SASM) variability, based on speleothem oxygen-isotope data from the Amazon Basin. South American Summer Monsoon variability and that of a major Northern Hemisphere monsoon–that is, the Asian monsoon3,4–have been strikingly out of phase. However, we observe occasional synchronous behaviour in regions impacted by both monsoons. We identify a synchronicity threshold that is exceeded during ten events, including during glacial terminations. Comparison with palaeoclimatic forcing factors during these intervals indicates that greenhouse gas concentrations, cross-equatorial thermal gradients and sea surface temperatures in both the Atlantic and Pacific probably influence these events. This record demonstrates that the global monsoon can reorganize itself, especially during intervals of rapidly changing planetary boundary conditions.
Palaeoclimate, Climate and Earth system modelling, Geochemistry
A microexon regulatory code reveals autism-linked genetic variation
Original Paper | RNA splicing | 2026-10-13 20:00 EDT
Guillermo E. Parada, Hannes Bretschneider, Jack Daiyang Li, Jacob L. Fine, Steven J. Dupas, Jonathan D. Ellis, Ulrich Braunschweig, Sophie Bonnal, Taykhoom Dalal, Worrawat Engchuan, Mehdi Zarrei, Wei Wei, Nadia Zafar, Martin Hemberg, Liliana Attisano, James Ellis, Manuel Irimia, Michael Wainberg, Brett Trost, Stephen W. Scherer, Quaid D. Morris, Benjamin J. Blencowe
Neuronal microexons are a highly conserved class of alternative splicing events enriched in genes with critical functions in nervous system biology1,2. Microexon splicing is often disrupted in the brains of autistic individuals, and mice with microexon deficiencies display autism-like phenotypes1,3,4. However, the full landscape of microexons is not known, and the impact of genetic variation on these exons has not been systematically investigated. Here, through extensive transcriptome profiling, we detect hundreds of new microexons, including many with neuronal subtype-specific splicing patterns, and others that activate nonsense-mediated mRNA decay. Using machine learning, we define a sequence code predictive of neuronally spliced microexons and use this to identify critical regulatory elements surrounding the expanded microexon repertoire. This code further reveals genomic variants predicted to alter microexon splicing in individuals affected by autism, with rare variants having the strongest estimated impact. These variants are mostly detected in idiopathic individuals and are associated with autism status. They also converge on synaptic and other autism-linked genes, as well as genes not previously linked to autism. Our results collectively define an expanded repertoire of microexons, delineate their regulatory code, and pinpoint variants predicted to affect their splicing, with implications for the disruption of functions central to neuronal biology and brain disorders.
RNA splicing, Autism spectrum disorders
Educational intervention can rewire village social networks
Original Paper | Sociology | 2026-10-13 20:00 EDT
Marios Papamichalis, Laura Forastiere, Edoardo M. Airoldi, Nicholas A. Christakis
Social networks shape behaviour, affect information dissemination and undergird collective action. And they can be exploited in the design of interventions in these domains1,2,3,4,5,6,7. Although social networks obey fundamental principles, such as the degree distribution8,9, they can nevertheless evolve as ties form and break. Here, through a randomized controlled trial involving a total of 8,331 people in 110 remote Honduran villages, we evaluate the secondary effects of a 22-month public-health intervention1 on pre-existing social-network structure. We used a design in which a varying fraction of village households received the intervention, and villages in which no one received the intervention were used as the primary reference group. In ‘low-dosage’ villages (in which 5-30% of households received the intervention), people who received the intervention tended to sever ties with untreated individuals to whom they previously went for health advice. Conversely, in high-dosage villages (50-100%), treated individuals increased their ties. These average changes are explained mainly by tie dynamics; that is, treated-treated pairs persist and form new links, whereas treated-untreated ties dissolve. A mediation analysis indicates that absorption of health information increases the likelihood of tie formation and persistence. The rewiring patterns generally lasted for three years after the intervention ceased. Moreover, although the intervention delivered health information, it reshaped friendship and financial ties, not just health-advice connections. In aggregate, the introduction of a new information regime acted as a kind of social institution, rewiring individuals’ connections even though the overall degree distribution of village-wide networks remained relatively stable.
Sociology, Society, Public health, Economics
Advancing subseasonal forecasting with machine learning
Original Paper | Projection and prediction | 2026-10-13 20:00 EDT
Hannah Guan, Soukayna Mouatadid, Paulo Orenstein, Judah Cohen, Haiyu Dong, Zekun Ni, Jeremy Berman, Genevieve Flaspohler, Alex Lu, Jakob Schloer, Joshua Talib, Jonathan A. Weyn, Lester Mackey
Decision-makers rely on weather forecasts to plant crops, manage wildfires, allocate water and energy and prepare for weather extremes1,2,3. Today, such forecasts enjoy unprecedented accuracy as far as 2 weeks thanks to steady advances in physics-based dynamical models and data-driven artificial intelligence models4,5,6,7,8,9,10. However, model skill drops precipitously at subseasonal timescales (2-6 weeks ahead) due to compounding errors, systemic model biases and the chaotic nature of the atmosphere11,12,13,14,15. To counter this degradation, we introduce probabilistic bias correction, a machine learning framework that substantially reduces systematic error by learning to correct historical probabilistic forecasts. When applied to the leading dynamical and artificial intelligence models from the European Centre for Medium-Range Weather Forecasts (ECMWF), probabilistic bias correction doubles the modest subseasonal skill of the AI Forecasting System16 and improves the skill of the operationally debiased dynamical model17 for 91% of pressure, 92% of temperature and 98% of precipitation targets. We designed probabilistic bias correction for operational deployment, and, in the 2025 real-time forecasting competition of ECMWF18, its global forecasts were the best for all weather variables and lead times, outperforming the dynamical models from six operational forecasting centres, an international dynamical multimodel ensemble, the AI Forecasting System of ECMWF and the forecasting systems of 34 teams worldwide. These probabilistic skill gains translate into more accurate prediction of extreme events and have the potential to improve agricultural planning, energy management and disaster preparedness in vulnerable communities19.
Projection and prediction, Climate and Earth system modelling, Atmospheric dynamics
Jurassic flightless bird reveals early ecological diversity of avialans
Original Paper | Palaeontology | 2026-10-13 20:00 EDT
Liming Xu
(徐立明), Min Wang
(王敏), Ganmin Lin
(林淦旻), Liping Dong
(董丽萍), Ke Deng
(邓克), Xing Xu
(徐星), Honggang Du
(杜红岗), Min Lin
(林敏), Runsheng Chen
(陈润生), Zhonghe Zhou
(周忠和)
The origin and early diversification of birds remain highly debated in vertebrate evolution. Although estimates of the evolutionary timescales suggest a Jurassic period radiation1,2, a profound scarcity of fossils from this period has hampered how the distinctive bird bauplan was assembled3,4,5. Selection for powered flight has been viewed as the primary driver of early avialan skeletal modifications3,6,7, attesting to the independent occurrences of aerodynamic features among paravian lineages8. Here we report on the discovery of a Late Jurassic avialan, Yuezhuornis yangyuanensis, gen. et sp. nov., from the Zhenghe Fauna of southeastern China9. As one of the earliest diverging avialans, Y. yangyuanensis exhibits a striking mosaic of features, combining a mixture of avialan- and troodontid-like cranial characters, paired with derived postcranial traits and a deinonychosaur-like hyperextensible second pedal digit. Phylogenetically informed analyses show that Y. yangyuanensis possesses markedly short forelimbs–a condition present widely among non-avialan theropods. These findings provide strong evidence for a terrestrial, flightless lifestyle of Y. yangyuanensis. Our study demonstrates that evolution works intensively as exemplified by the occurrence of several, divergent ecological pathways being exploited in the initial diversification of birds.
Palaeontology, Taxonomy
Nature Nanotechnology
Gate-induced layer sliding drives non-volatile switching of magnetism in tetralayer graphene
Original Paper | Electronic properties and devices | 2026-10-13 20:00 EDT
Daniel Brandon, Tixuan Tan, Yiwen Ai, Kyle Nadel, Peter Golemis, Akshat Gandhi, Lujin Min, Wenjun Zheng, Kenji Watanabe, Takashi Taniguchi, Mengkun Liu, Trithep Devakul, Kenji Yasuda
Layer stacking in two-dimensional materials can strongly impact electronic phases. In graphene, for instance, the metastable rhombohedral stacking arrangement hosts correlated and topological electronic phases, which are absent in conventional Bernal stacking. Here we use the sliding-induced first-order structural phase transition between Bernal and rhombohedral tetralayer graphene driven by gate voltages to manipulate the magnetic phase of the sample. Through transport measurement on marginally twisted double-bilayer graphene samples, we observe bistable switching between a Bernal-dominant state and a rhombohedral-Bernal mixed state across a wide space of the gate-voltage phase diagram. The structural phase transition induces a non-volatile switching between a non-magnetic and a ferromagnetic phase. We characterize the latter phase via low-temperature electric transport measurements and observe an anomalous Hall effect. The sign reversal of the anomalous Hall signal under opposite displacement fields suggests that the Hall signal may originate from domain boundaries between Bernal and rhombohedral regions. Our experiments showcase how gating-induced sliding phase transitions of two-dimensional materials can provide on-demand toggle switching between complex phases and offer insights on the effect of stacking domain boundaries on the global response of the system.
Electronic properties and devices, Magnetic properties and materials, Electronic properties and materials, Magnetic devices
Cryogenic shock exfoliation for ultrahigh mobility rhombohedral graphite nanoelectronics
Original Paper | Electronic properties and devices | 2026-10-13 20:00 EDT
Ludwig Holleis, Youngjoon Choi, Canxun Zhang, Jack H. Farrell, Gabriel Bargas, Audrey Hsu, Zexing Chen, Ian Sackin, Wenjie Zhou, Yi Guo, Thibault Charpentier, Yifan Jiang, Benjamin A. Foutty, Aidan Keough, Martin E. Huber, Takashi Taniguchi, Kenji Watanabe, Andrew Lucas, Andrea F. Young
Rhombohedral multilayer graphene offers a tunable platform for correlated electron physics, featuring field-effect control of magnetic, superconducting and topological phases. The promise of these materials has been held back by the limited abundance of rhombohedral stacking in natural graphite, which constrains both sample yield and useful area. Here we introduce cryogenic shock exfoliation to produce large-area rhombohedral graphene flakes. This exfoliation, combined with a low-pressure van der Waals assembly technique that preserves stacking order, enables highly uniform devices exceeding 1,300 μm2 in area with fabrication yields of ∼90%. Using scanning nanoSQUID-on-tip imaging, we demonstrate uniform spin magnetism over the full central 10 × 10 μm2 area of our devices. Transverse magnetic focusing reveals a disorder mean free path exceeding 200 μm at low temperatures. Within the flat surface bands of rhombohedral multilayer graphene, we observe a size-driven crossover from Poiseuille to porous electron flow in the intermediate-temperature regime of strong electron-electron hydrodynamics, providing a further signature of ultrahigh device quality. Our approach overcomes a key materials bottleneck in the fabrication of mesoscopic rhombohedral graphene devices, paving the way for incorporating strongly correlated phases into two-dimensional nanoelectronics.
Electronic properties and devices, Mechanical and structural properties and devices
Physical Review Letters
Far-from-Equilibrium Thermodynamics of Non-Abelian Thermal States
Article | Quantum Information, Science, and Technology | 2026-10-13 06:00 EDT
Franklin L. S. Rodrigues and Eric Lutz
Noncommutativity of observables is a defining feature of quantum physics. It plays a fundamental role in the formulation of the uncertainty principle for complementary variables and strongly affects the thermodynamic behavior of systems with noncommuting, that is, non-Abelian, conserved quantities. …
Phys. Rev. Lett. 137, 160401 (2026)
Quantum Information, Science, and Technology
Multipartite Mixed-Species Entanglement over a Quantum Network
Article | Quantum Information, Science, and Technology | 2026-10-13 06:00 EDT
D. Main, P. Drmota, E. M. Ainley, A. Agrawal, D. Webb, S. Saner, O. Bǎzǎvan, B. C. Nichol, R. Srinivas, D. P. Nadlinger, G. Araneda, and D. M. Lucas
We generate multipartite entangled states of two, three, and four matter qubits, where the entanglement is distributed over macroscopic distances via a photonic network link. Trapped-ion qubits are entangled directly via an optical fibre link, and the entanglement is subsequently extended to
Phys. Rev. Lett. 137, 160801 (2026)
Quantum Information, Science, and Technology
Evidence of Galaxy Cluster Rotation and Intrahalo Gas Motions in the Cosmic Microwave Background
Article | Cosmology, Astrophysics, and Gravitation | 2026-10-13 06:00 EDT
Samuel Goldstein and J. Colin Hill
Thomson scattering of cosmic microwave background photons off rotating intracluster gas reveals a secondary anisotropy associated with the rotational kinematic Sunyaev-Zel'dovich effect.
Phys. Rev. Lett. 137, 161001 (2026)
Cosmology, Astrophysics, and Gravitation
Perturbative Approach to Symmetric Mass Generation
Article | Particles and Fields | 2026-10-13 06:00 EDT
Simon M. Martin and Tarun Grover
The Landau paradigm has been a powerful framework for understanding phase transitions involving spontaneous symmetry breaking. In contrast, phase transitions between two symmetric phases, where neither phase breaks any symmetry, remain less explored. One intriguing class of such transitions involves…
Phys. Rev. Lett. 137, 161601 (2026)
Particles and Fields
Photon-Statistics Time Delay in Quantum Attosecond Photoelectron Interferometry
Article | Atomic, Molecular, and Optical Physics | 2026-10-13 06:00 EDT
Liding Li, Xu Zhang, Shouyu Xiao, Yang Li, Peixiang Lu, and Yueming Zhou
Photoelectron interference can reveal otherwise hidden properties of quantum light through an apparent attosecond time shift.
Phys. Rev. Lett. 137, 163201 (2026)
Atomic, Molecular, and Optical Physics
High-Performance Quantum Frequency Conversion from Ultraviolet to Telecom Band
Article | Atomic, Molecular, and Optical Physics | 2026-10-13 06:00 EDT
Yi Yang, Bin Wang, Ji-Chao Lin, Yang Gao, Xin Li, Jiu-Peng Chen, Lei Hou, Ye Wang, Yong Wan, Xiu-Ping Xie, Ming-Yang Zheng, Qiang Zhang, and Jian-Wei Pan
Quantum frequency conversion (QFC) is essential for bridging the spectral gap between stationary qubits and low-loss optical communication channels. Practicable QFC interfaces connecting ultraviolet and telecommunication bands are of great significance but have remained elusive, constrained by the d…
Phys. Rev. Lett. 137, 163601 (2026)
Atomic, Molecular, and Optical Physics
Magnon Kerr Effect in a Magnetic Thin Film Strongly Coupled to a Microwave Resonator
Article | Atomic, Molecular, and Optical Physics | 2026-10-13 06:00 EDT
Davit Petrosyan, Hiroki Matsumoto, Hanchen Wang, Jamal Ben Youssef, Richard Schlitz, William Legrand, and Pietro Gambardella
Progress in cavity magnonics relies on tunable nonlinearities in magnon-photon interactions for controlling magnon dynamics and frequency conversion. Here, we demonstrate the magnon Kerr effect in anisotropic magnonic systems comprising iron garnet thin films coupled to a loop-gap microwave resonato…
Phys. Rev. Lett. 137, 163602 (2026)
Atomic, Molecular, and Optical Physics
Physical Review X
Tripartite Haar Random State Has No Bipartite Entanglement
Article | | 2026-10-13 06:00 EDT
Zhi Li, Takato Mori, and Beni Yoshida
Researchers demonstrate that bipartite Einstein-Podolsky-Rosen entanglement cannot be distilled from tripartite Haar random states by local operations.
Phys. Rev. X 16, 041013 (2026)
Mixed-State Phases from Local Reversibility
Article | | 2026-10-13 06:00 EDT
Shengqi Sang, Leonardo A. Lessa, Roger S. K. Mong, Tarun Grover, Chong Wang, and Timothy H. Hsieh
Researchers establish a framework using local reversibility to correctly classify phases of matter in open and noisy quantum systems.
Phys. Rev. X 16, 041014 (2026)
arXiv
Non-Monotonic Exciton Transport Efficiency in Multi-layer Ring-shaped Quantum Networks inspired by Photosystem I
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Yi Li, Rui Li, Kai-Ya Zhang, Ming-Zi Jin, Tao Liu, Qing Ai
Photosystem I (PSI) is one of the most efficient natural photosynthetic complexes and serves as a structural prototype for understanding excitation energy transfer (EET) and designing artificial light-harvesting systems. Here, we construct a multilayer elliptical-conical quantum network inspired by PSI to investigate how antenna architecture affects EET. Excitation dynamics are simulated using the quantum jump approach combined with coherent modified Redfield theory (QJA-CMRT). The transfer efficiency exhibits a pronounced nonmonotonic dependence on pigment density, reaching a maximum of 0.86 at x=6 in the five-layer network. The optimal configuration contains 91 pigments, close to the number of core antenna pigments in natural PSI. Our combined density-of-states and kinetic analyses reveal that this nonmonotonic dependence originates from a trade-off: at low pigment densities, enhanced band overlap promotes energy transfer, whereas at high densities, excessive exciton delocalization compromises funnel directionality and reduces efficiency; the optimal configuration is consequently achieved at x=6. These findings provide insights into PSI antenna organization and offer guidelines for designing efficient artificial light-harvesting systems.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Quantum Physics (quant-ph)
13 pages,6 figures
Real-Space Interference from Quantum Metric
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Bo-Qing Wu, Xing-Lei Ma, Jin-Xin Hu, Jinchao Zhao, K. T. Law
Real-space interference of wave packets is governed by their central momentum separation and momentum width, which set the oscillation wavelength and spatial envelope, respectively. Here, we show that in crystalline systems, quantum metric distribution in an isolated band can similarly give rise to real-space interference through the evanescent tails of a localized bound state. The location and width of a quantum metric hot spot in the momentum space set a complex wavevector as one evanescent plane wave component of a bound state. Consequently, with multiple quantum metric hot spots, the density distribution of a bound state or the total density of two spatially overlapped bound states exhibits an interference pattern, where the oscillation period and long-range decay length are determined by the momentum-space separation of the hot spots and the width of the narrowest hot spots, respectively. This quantum-geometric interference is particularly pronounced in (nearly) flat bands, where competing scales from band dispersion are suppressed. Furthermore, we demonstrate that using a Josephson STM the real-space interference can be experimentally observed through the tip-position dependence of the Josephson critical current. Our results reveal a direct correspondence between momentum-space quantum geometry and real-space interference, showing how bound-state profiles encode the momentum-resolved quantum metric.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Domain of Applicability of the Distorted Wave Born Approximation (DWBA): A Critical Analysis for X-ray and Visible-Light Interface Scattering
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
The Distorted Wave Born Approximation (DWBA) is established for X-ray interface scattering, yet its domain of applicability has never been stated explicitly. The DWBA implicitly rests on the small refractive index deviation (SRID) condition - satisfied by X-rays ($ |n-1| \sim 10^{-6}$ ) but violated by visible light ($ |n-1| \sim 0.5$ ). The DWBA mixes microscopic and macroscopic Maxwell equations, whereas a rigorous optical theory must be built on the macroscopic Maxwell equations and constitutive relations. Rigorous alternatives for two specific inconsistencies in the standard DWBA are discussed. The Extended Transfer Matrix Approach (ETMA) for visible-light interface scattering is outlined.
Soft Condensed Matter (cond-mat.soft), Optics (physics.optics)
14 pages, 1 figure, to be published in SciPost Physics
Hierarchical Multi-Agent Reasoning Systems for Knowledge-Grounded Material Substitution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Tarjei Paule Hage, Subhadeep Pal, Wei Lu, Yu-Chuan Hsu, Gayla Lyon, Jiezhu Jin, Markus J. Buehler
AI-assisted scientific discovery increasingly seeks to move beyond generating plausible ideas toward reproducible, constraint-aware workflows that can support practical engineering decisions. We present MARS, a hierarchical Multi-Agent Reasoning System for knowledge-grounded material substitution under scientific and manufacturing constraints. We apply MARS to replace per- and polyfluoroalkyl substances (PFAS), a demanding materials-design problem in which substitutes must satisfy functional performance, environmental, experimental, and processing requirements. MARS decomposes substitution into a closed-loop workflow comprising requirement analysis, grounded candidate generation, and manufacturability assessment with process design. The system integrates retrieval-augmented generation, knowledge-graph reasoning, a database of lab-available materials, persistent memory of intermediate results, and rejection-aware iterative feedback. In a PFAS-substitution case study, MARS generates structured material requirements, identifies an evidence-grounded substitute candidate, and develops a lab-scale manufacturing route. In a multi-seed ablation evaluation, MARS achieves the highest overall performance across all three subsystems, with gains that persist when the backbone model is held fixed. These results suggest that hierarchical decomposition, knowledge grounding, and manufacturability-aware refinement improve material-substitution reasoning beyond model capability alone.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Machine Learning (cs.LG)
IceCube data for astrophysical neutrinos exhibit q-statistical behavior
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Constantino Tsallis, Ugur Tirnakli
Relevant IceCube recent data for astrophysical neutrinos are analyzed. Similarly to cosmic rays and proton-proton LHC collisions, the corresponding spectra are satisfactorily described, for the entire interval of measured energies, through q-Gaussians. This fact reinforces the already available evidence that nonadditive entropies (either of the $ S_q$ class or of the $ S_{delta}$ one, or even alternative ones) appear to play a crucial role in systems such as black holes and related cosmological phenomena (e.g., dark energy). The IceCube data yield sensibly high values for the momenta-distribution nonadditive index (q \simeq 1.6), in contrast with the cosmic rays values (q \simeq 1.2) and the LHC values (q \simeq 1.1). This fact neatly indicates very-long-ranged space-time correlations. The detailed associated physical mechanisms remain, at the present stage, as an instigating open issue.
Statistical Mechanics (cond-mat.stat-mech), High Energy Astrophysical Phenomena (astro-ph.HE), High Energy Physics - Phenomenology (hep-ph)
10 pages, 1 figure
On physical implementability of reinforcement-learning-driven reasoning
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-14 20:00 EDT
In the machine learning community, the reinforcement-learning-driven reasoning process has been intensively studied since around 2025. In this article, we present a negative result on the hardware implementation of this reinforcement-learning-driven reasoning process in a physical neural network model in the presence of a reward external potential energy for a given reward. In this hardware implementation, the existence of a chain of thought in dynamics contradicts the Lyapunov stability of the system.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG)
3 pages, revtex
Electric-dipole-induced nuclear electric resonance in silicon
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Jiyun Su, Shihang Zhang, Peihao Huang
The nuclear spin of a phosphorus atom in silicon is considered as a promising quantum information carrier for quantum computing due to its long coherence time. Coherent control of the nuclear spin is typically realized using nuclear magnetic resonance (NMR). In this work, we theoretically propose that with the aid of hyperfine interactions and magnetic field gradients, fast electric-dipole-induced nuclear electric resonance (EDNER) can be achieved. The stronger EDNER (compared with NMR) arises from the combined effects of hyperfine interaction between the nuclear and electron spins and coupling between the electron spin and charge degrees of freedom mediated by magnetic field gradients in this scheme. By operating at specific working points, the nuclear-spin splitting becomes less sensitive to electrical noise, enabling long coherence times and high-fidelity quantum operations. All elctrical, addressable control of nuclear spins paves the way for scalable silicon-based quantum computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
7 pages, 8 figures
In-Situ TEM Observation of Solid-State Phase Evolution in High-Entropy Alloy Nanoparticles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Nirmal Kumar Katiyar, Noorbasha Bhavani Sai, Guilherme Gurian Dariani, Douglas S. Galvao, Pulickel M. Ajayan, Pedro Alves da Silva Autreto, Sriram Vijayan, Chandra Sekhar Tiwary
The emergence of new materials has gone beyond conventional design principles. Among them are high entropy alloys (HEAs), in which multiple metallic elements coexist within a single unit cell. In this case, each atomic position in a solid material has a different chemical environment, leading to configurational entropy as high as that in the fully random or melted state, which has been frozen to a solid solution. However, the behaviour of such alloy systems at pre-melting temperatures is largely unknown, where atoms gain sufficient mobility and time to rearrange, leading to an enthalpic rather than an entropic interplay. This study demonstrated the phase transformation of HEA nanoclusters (CoCrFeMnNi) under high-resolution transmission electron microscopy (HRTEM) at different temperatures, including room temperature (RT), 550 °C, and 850 °C. The clustered nanoparticles coarsen into larger clusters, accompanied by compositional heterogeneity due to surface and lattice diffusion. This experimental finding of atomic mobility was further corroborated using molecular dynamics, which provides a detailed mechanistic description.
Materials Science (cond-mat.mtrl-sci)
Experimental observation of Higgs oscillations and their power-law decay across pairing regimes in a cavity QED quantum simulator
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-14 20:00 EDT
Chitose Maruko, Haoqing Zhang, Eliot A. Bohr, Leah Huzjak, Anjun Chu, Victor Gurarie, Chengyi Luo, Ana Maria Rey, James K. Thompson
Understanding how pairing correlations in superconductors evolve out of equilibrium is a central challenge in quantum many-body physics. In systems with $ s$ -wave pairing, the character of Cooper pairing evolves continuously from a BCS regime of weakly bound, overlapping pairs to a BEC regime of tightly bound molecules, each with distinct excitation spectra. Here we realize and probe pairing dynamics across these regimes using cold, non-degenerate $ ^{87}$ Rb atoms coupled to an optical cavity with Floquet dressing. Our cavity-QED platform emulates fermionic superfluids through a mapping onto Anderson pseudospins, while optical and microwave control tunes the ratio of interactions to single-particle energies, providing a flexible approach complementary to ultracold Feshbach and ultrafast solid-state platforms. Following a quench, we observe persistent pairing and transient oscillations of the order parameter associated with a collective amplitude (Higgs) mode. We find that the decay of these oscillations sharply distinguishes weak- and strong-pairing regimes: in the weak-pairing regime, oscillations decay with a power-law exponent $ |\alpha|=0.65(8)$ , whereas in the strong-pairing regime the decay is substantially faster, with $ |\alpha|>1$ . The oscillation frequency is set by the minimum quasiparticle excitation energy, directly linking nonequilibrium dynamics to the underlying excitation spectrum. Our results establish nonequilibrium dynamics as a direct probe of pairing character and collective excitations in interacting quantum systems.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
Exact SU($N$) symmetry resolution of bosonic Hubbard models: general boson-fermion mappings and flat-band singlet-cluster states
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
We show how to perform exact diagonalization of SU($ N$ )-symmetric Bose-Hubbard models separately in each irreducible representation of SU($ N$ ), by exploiting the Howe duality between U($ L$ ) and U($ N$ ). Three structural consequences follow for any lattice and any Hamiltonian built from the U($ L$ ) generators: (i) the spectrum in a given orbital sector is independent of $ N$ and of the particle statistics, (ii) the canonical partition functions for bosons and fermions obey the exact identity $ Z_{\mathrm{b}}(-N)=(-1)^{N_\mathrm{b}}Z_{\mathrm{f}}(N)$ , (iii) with unfrustrated hopping the groundstate is always a color ferromagnet, so that the color-resolved method we introduce is useful to study excited sectors, frustrated lattices and finite temperatures. As applications, we first derive the finite-temperature phase diagram of attractive SU($ N$ ) bosons on few-site rings at large $ N$ for arbitrary filling. We then show the emergence of singlet-cluster states from frustrated hopping, the counterpart of fermionic ferromagnetism, with the example of the sawtooth and kagome lattice.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas), Mathematical Physics (math-ph)
Precursor stoichiometry controls dopant structure, defect chemistry, and valence in Mn-doped ZnGa$_2$O$_4$ nanocrystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Mátyás M. Rudolf, Gábor Bortel, Nikoletta Jegenyés, Árpád Jakab, László Bencs, Ferenc Simon, Adam Gali, Dávid Beke
The luminescence of doped nanocrystals is usually optimised through the activator; here we show that the host cation ratio is an equally decisive, and largely overlooked, design variable. Mn-doped ZnGa$ _2$ O$ _4$ nanocrystals (Mn:Zn = $ 4\times10^{-4}$ ) were grown hydrothermally at nominal Zn/Ga ratios between 0.30 and 0.75 (stoichiometric: 0.50) and post-annealed at 400–1100$ ^\circ$ C, and the resulting composition–temperature matrix was mapped by X-ray- and UV-excited luminescence, EPR, Rietveld-refined X-ray diffraction, Raman spectroscopy and SEM. The as-grown crystals are phase-pure spinel at every composition and accommodate their off-stoichiometry internally as a point-defect inventory, reflected in a 0.4% variation of the lattice parameter; on annealing, the excess gallium is exsolved as $ \beta$ -Ga$ _2$ O$ _3$ in amounts set by the solution composition. The Mn$ ^{2+}$ emission separates into two optima, near-stoichiometric crystals annealed at 400–600$ ^\circ$ C and Zn-excess crystals annealed at 1100$ ^\circ$ C, the latter being twice as bright under X-ray excitation. Under X-ray and 365~nm excitation the two optima are separated by a minimum at 800$ ^\circ$ C that coincides with a collapse of the Mn$ ^{2+}$ EPR population and has no counterpart in the Raman linewidths, identifying transient, defect-compensated oxidation of the dopant rather than lattice degradation as its origin. The most Zn-rich composition shows neither Mn$ ^{2+}$ nor Mn$ ^{4+}$ emission at any annealing stage, whereas its trace Cr$ ^{3+}$ emission is strong, indicating that Mn is rejected already during growth. Solution stoichiometry therefore acts on two levels, dopant capture and native-defect inventory, while annealing controls dopant valence and lattice order. The brightest high-temperature phosphor is thus not the nominally stoichiometric one, but the composition whose excess is consumed on its way to stoichiometry.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Optics (physics.optics)
30 pages: 9 pages main text with 5 figures, 21 pages Supporting Information with 18 figures and 1 table
Anisotropic pressure response of thermal conductivity in crystalline polytetrafluoroethylene
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Maissa Adi, Jamal Abou Haibeh, Samuel Huberman
Compression can change thermal conductivity differently along polymer chains and across them by altering phonon velocities and lifetimes. We examine this directional response in orthorhombic Form III polytetrafluoroethylene (PTFE) at calculated pressures of 1.503, 3.452, and 5.056 GPa, using first-principles harmonic and cubic force constants within the single-mode relaxation-time approximation (SMRTA). At 100, 200, and 300 K, the chain-axis conductivity decreases at every pressure step. Between 3.452 and 5.056 GPa, both transverse components recover: at 300 K they increase by 23.7% and 13.7%, while the longitudinal conductivity decreases by 14.5%. An exact factorization separates the conductivity into a heat-capacity–velocity factor and a weighted effective lifetime. The transverse recovery follows from larger heat-capacity-weighted squared velocities, consistent with stiffer interchain restoring forces. Along the chains, shorter effective lifetimes dominate, and both conductivity-weighted Normal and Umklapp rates increase at 300 K. Comparing the same cubic force-constant blocks at all three pressures, we find that interchain coupling is already substantial at 1.503 GPa and increases under compression.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Emergence of quantum transport in SnTe films upon structural refinement
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Shrinkhala Sharma, Rabindra Basnet, Thomas Parker, Afolabi Akinfaderin, Alexander Samokhvalov, Rajeswari Kolagani, Ramesh C. Budhani
Topological crystalline insulators are distinguished from the conventional Z2 topological insulators by crystalline symmetry protection of the surface states. Quantitative characterization of these states requires magneto-transport measurements from which the phase coherence length and number of independent coherent channels can be extracted. Here we report such measurements on textured thin films of SnTe grown on Bi2Te3 buffered c-plane sapphire (Al2O3) by pulsed laser ablation. A post deposition annealing protocol was implemented to control the crystallographic texture, which reveals improved crystallinity and enhanced epitaxial alignment along the [111] direction in films annealed at elevated temperatures. The higher carrier density and lower resistivity seen in films annealed at 100 oC are suggestive of Sn vacancies which act as native acceptor defects, while films annealed at 200 oC approach the 1:1 stoichiometry. The magnetoresistance of all samples at T < 10 K characterized by a cusp centered around zero-field is suggestive of weak antilocalization and interpreted in the framework of the Hikami-Larkin-Nagaoka theory in the strong spin-orbit coupling limit. At T > 20 K, the MR is small and positive, and deviates from conventional Kohler scaling. An approximate collapse of the MR curves between 50 and 250 K is obtained using an empirical temperature-dependent scaling factor, indicating that changes in the Hall-derived carrier density alone cannot account for the observed scaling behavior. These results demonstrate that post growth annealing strongly influences the interplay between stoichiometry, crystallinity, and coherent transport in SnTe thin films.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Benchmarking machine-learning interatomic potentials using classical force fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Johannes Sandberg, Geneviève Dusson, Julien Lam
We propose a rational comparison between several well-known machine-learning interatomic potentials (linear atomic cluster expansion, the Behler-Parrinello high-dimensional neural network potential, and the graph neural network-based MACE potential) by testing their performance for fitting classical potentials such as the Lennard-Jones and Stillinger-Weber potential. With this we assess their advantages and limitations regarding several aspects: varying training dataset size, robustness to noise, carbon footprint, as well as the ability to reproduce the radial distribution function as an example observable. Overall the MACE models are shown to most accurately reproduce the potential energy surface, with little sign of overfitting, but at a significant computational cost, highlighting important questions regarding the choice of models in computational materials science.
Materials Science (cond-mat.mtrl-sci)
Partitioning the magnetization raises the stability limit of ferromagnetic colloids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Paramita Modak, Priyadharshini M, Ankur Jaiswar, Ambarish Ghosh
Magnetic actuation scales with a particle’s magnetic moment, yet practical colloidal suspensions remain superparamagnetic or weakly magnetized, a permanent dipole drives a near contact attraction growing as the square of the moment, binding particles irreversibly. Here we show that this constraint depends not only on how much magnetic material a particle carries, but on where it sits. Partitioning a fixed moment M into N internal elements leaves the far field interaction, and every actuation force, unchanged while suppressing the near-field pair energy by 1/N. As we show in our experiments across 57 samples and three geometries, stability collapses onto a single $ \sim M^{2}/N$ boundary, raising the accessible dipolar energy scale nearly 150-fold. A liquid-phase analogue of magnetic force microscopy images the engineered energy landscape directly. The resulting colloids outrun size-matched superparamagnetic beads in weak fields far from a magnetic source, suggesting their applicability in hard to reach places. Together, these results open a new operating regime for colloidal manipulation, with impactful implications in microfluidics and drug delivery.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
18 pages, 6 figures
Explicit Solutions in a Probabilistic Cellular Automaton Model for Self-Assembled Monolayer Degradation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Wes Caldwell, Ryan Evans, Jacob Majikes, Anthony Kearsley
Self-assembled monolayers (SAMs), formed by the adsorption of a monomolecular layer of adsorbate onto a surface, have emerged as leading candidates for plat- forms for electrochemical biosensors. In order to characterize the working age of a SAM-based biosensor, it is necessary to understand the long-term degradation of the monolayer, with particular emphasis on the intermolecular forces present in the self-assembly process. In this work, discrete- and continuous-time proba- bilistic cellular automaton (PCA) models for the degradation of SAMs involving adsorbate-adsorbate interactions are proposed in which adsorbate molecules desorb at a rate dependent only on the number of adsorbed neighbors. Impor- tantly, we make no assumptions on the relationship between degradation rate and adsorbed neighbors. Using techniques from generating function theory and complex analysis, the expected degradation curve is solved for explicitly in one dimension and shown to be a sigmoid curve related to the Gompertz function.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Combinatorics (math.CO)
Mn–Cr dopant association in dilute co-doped $\mathrm{ZnAl_2O_4}$ revealed by combined EPR and optical spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Apoko S. Omondi, Mátyás M. Rudolf, Nikoletta Jegenyés, Árpád Jakab, Gábor Bortel, Bence G. Márkus, Adam Gali, Dávid Beke
Efficient and durable phosphors made from abundant elements underpin energy-saving solid-state lighting, near-infrared light sources for sensing, and X-ray and biomedical imaging. Co-doping is a standard route to brighter phosphors, yet the fate of the co-dopants is rarely established. We combine quantitative electron paramagnetic resonance (EPR) spin counting with photoluminescence, photoluminescence excitation, and X-ray-excited spectroscopy across two dilute Mn/Cr co-doping series of hydrothermally grown $ \mathrm{ZnAl_2O_4}$ nanoparticles and show that the two ions can form an exchange-coupled, edge-sharing Cr–Mn defect complex, with $ \mathrm{Mn^{2+/4+}}$ entering an octahedral site next to $ \mathrm{Cr^{3+}}$ . The octahedral Mn lifts the inversion symmetry of the $ \mathrm{Cr^{3+}}$ site and strengthens its parity-forbidden absorption, enhancing the $ \mathrm{Cr^{3+}}$ emission without energy transfer. The population of the defect complex follows the law of mass action, and above a threshold Mn concentration, Mn re-partitions into EPR-silent octahedral configurations that quench both emissions. Concentration optima in co-doped phosphors can thus reflect defect speciation, not only energy-transfer efficiency, which opens a structural design handle for brighter emitters.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
18 pages, 8 figures; Supplementary Information included (8 figures, 8 tables)
Establishing the role of thickness in LaOBr; an alternative gate dielectric for vdW heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Isaac Antoine Lagaud, Justin Boddison-Chouinard, Antoine Labbé, Ayse Melis Aygar, Alex Bogan, Li-Lin Tay, Takashi Taniguchi, Kenji Watanabe, Aljoscha Söll, Zdeněk Sofer, Adina Luican-Mayer, Louis Gaudreau
In electronic devices, the quality of the dielectric material is determined by figures of merit such as the band gap, leakage onset field, breakdown field and the number of built-in defects, which can all limit device performance. An additional and important metric to consider is the strength of the dielectric constant. Hexagonal boron nitride (hBN) is the benchmark gate dielectric for two-dimensional van der Waals heterostructures, owing to its wide bandgap, and atomically flat interface. At the same time, its dielectric constant (2–4) highlights the opportunity to explore alternative higher-permittivity van der Waals dielectrics that provide stronger electrostatic control. Previous work established lanthanum oxybromide (LaOBr), a layered dielectric with a predicted dielectric constant of 12.5, as a potential dielectric for van der Waals heterostructures. Using graphene field-effect devices with LaOBr, we show that the leakage-onset and breakdown fields decrease systematically with thickness. Dual-gate capacitance measurements combined with a dead-layer model reveal a bulk dielectric constant of $ \varepsilon_{\mathrm{bulk}} = 12.2$ , in agreement with theory, while interfacial dead-layers cause the effective dielectric constant to vary from 6 to 11 across multiple thicknesses. Benchmarked against established gate dielectrics, LaOBr combines breakdown fields comparable to hBN with dielectric constants 2 to 3 times larger. By establishing the operating regime of devices with various thicknesses, we further confirm the advantage of LaOBr over hBN for high-capacitance gate-dielectric operation. These results validate LaOBr as a promising dielectric for integration into two-dimensional heterostructures, and establish thickness-dependent benchmarking as essential for evaluating emerging layered dielectric materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Revealing New Leakage Paths in GAAFETs using Predictive First-Principles Simulations
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-14 20:00 EDT
Denis Mamaluy, Juan P. Mendez, Coleman Cariker, Michael Titze, Alex A. Belianinov
Gate-All-Around Field-Effect Transistors (GAAFETs) are emerging as successors to Fin Field-Effect Transistors (FinFETs) and are central to continued scaling at advanced semiconductor nodes. Despite their improved electrostatic control, recent measurements show that the drain current in GAAFETs deviates strongly from thermionic behavior at negative gate voltages, increasing as the gate voltage becomes more negative. This leakage has been attributed to direct gate-drain tunneling through the high-$ k$ dielectric, enhanced by drain-induced dielectric barrier lowering (DIDBL). Here, we use predictive, charge-self-consistent Non-Equilibrium Green Function (NEGF) simulations based on the Contact Block Reduction (CBR) method to spatially resolve this leakage pathway in GAAFETs. Unlike approaches based primarily on phenomenological leakage models, our first-principles, multi-terminal quantum-transport framework treats the source, drain, and gate as current-carrying quantum-mechanical contacts and resolves the local current density throughout the device. The spatially resolved current density shows that gate-injected carriers tunnel through the high-$ k$ dielectric preferentially near the drain side of the gate, where the dielectric barrier is most strongly lowered by the drain bias, and are collected by the drain. This provides a direct real-space picture of the DIDBL-driven gate-drain leakage mechanism.
Other Condensed Matter (cond-mat.other)
A Solution-Processed Ti/Pt/NiOx/Ag RRAM Device with Multiple Forming-Free Non-Volatile Intermediate States
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Abhrajit Roy, Chopali Chanchal Sahu, Rudraksh Sangore, Raman Hissariya, Poulomi Chakrabarty, Harsh Roniyar, Merlyne De Souza, Debanjan Bhowmik
Artificial neural networks (ANN) implemented on crossbar arrays of non-volatile synaptic devices are known to consume much less energy compared to that implemented on conventional computing units. Solution-processed resistive random-access memory (RRAM) devices based on transition-metal oxides are suitable as such synaptic devices because of their cheap and easy fabrication method, stability, and suitable memristive properties. Here, in NiO-based RRAM devices with Ti/Pt as the bottom electrode and Ag as the top electrode (NiO layer deposited through solution processing), we experimentally report forming-free binary switching between a high resistance state (HRS) and a low resistance state (LRS) as well as forming-free pulse-driven modulation (long-term potentiation (LTP), long-term depression (LTD)) through 30 intermediate synaptic states between HRS and LRS (around 5-bit synaptic weight resolution). Many of these states are measured to be stable at least up to 1000 seconds confirming their non-volatility and their utility in storage of synaptic weights for ANN crossbar arrays. On the contrary, most prior experimental reports (including reports both on solution-processing-based and sputtering-based RRAM devices) require forming to exhibit non-volatility. Avoiding forming reduces variability, eliminates the need for high voltage pulses, and makes the crossbar array design simpler. Further, we confirm the presence of oxygen vacancies in our materials stack using X-ray photo-electron spectroscopy (XPS). Finally, we show successful data classification on MNIST and CIFAR-10 data sets using a multi-layer perceptron (MLP) model and a convolution neural network (CNN) model respectively, where the synaptic weight updates of these ANN models are calibrated against the experimentally measured LTP-LTD characteristics of the NiO RRAM devices.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
43 pages including main article and supporting information, 6 figures and 3 tables in main article, 4 figures and 4 tables in supporting information
Competitive scaling of small-subsystem-optimization heuristics for LABS
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
The low autocorrelation binary sequences (LABS) problem, often formulated as a spin-lattice energy-minimization problem, is a combinatorial optimization problem with a very rugged energy landscape. We demonstrate that iterative optimization of very small subsystems of n spins that are decoupled from the rest of the system achieves global optimization of LABS with a time-to-solution scaling that is competitive with heuristics that optimize the global system of N spins directly. Our isolated-subsystem heuristic with n = 4 achieves a time scaling of O(1.333N ) on the interval N = [27, 60], while the current state-of-the-art classical and quantum scalings are respectively O(1.34N ) and O(1.21N ). Our results suggest that specialized optimization hardware with only small numbers of logical spins may be of practical relevance.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
9 pages, 5 figures
Explicit Solvents Reverse Temperature Dependence of Phase Behavior in Charged Fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Pierre J. Walker, Zhen-Gang Wang
In most theories of electrolyte and polyelectrolyte solutions, the solvent is treated implicitly as a dielectric continuum. While this approximation has enabled major advances, it neglects coupling between ionic and dipolar degrees of freedom. Using molecular dynamics simulations and the mean-spherical approximation, we show that this coupling qualitatively alters electrostatically driven phase behaviour. At finite ion concentrations, many-body ion-dipole correlations reverse the temperature dependence of effective electrostatic interactions, leading to upper-critical solution temperature (UCST) behaviour in direct contrast to the lower-critical solution temperature (LCST) behaviour predicted by implicit-solvent electrostatic theories. This phase reversal arises from ion-induced suppression of local dipolar screening, a collective effect inaccessible to pairwise implicit-solvent descriptions.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Direct Observation of Chirality-Dependent Berry Curvature Dipole via Cross-Axial Nonlinear Hall Effect in Trigonal Te
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Jaehyun Lee, Junhee Shin, Daryll J. C. Dalayoan, Miju Park, Changhee Sohn, Gang Qiu, Noejung Park, Binghai Yan, Tony Low, Hosub Jin, Seon Namgung
Quantum geometric quantities, such as Berry curvature (BC) and quantum metric, are known to govern the physical and topological properties of materials, making access to these quantities critically important for the comprehensive understanding of the materials. Chiral crystals offer a natural platform in which structural handedness can control quantum geometry and nonlinear transport, but direct experimental access to the quantum geometric quantities has remained elusive. Here, we show that trigonal tellurium (Te) hosts an enantiomer-dependent Berry curvature dipole (BCD) that can be accessed through the measurement of cross-axial nonlinear Hall effect (NHE), unlike previously studied in-plane configurations where the BCD contribution vanishes. Angle-resolved measurements on left- and right-handed Te devices reveal a second-order transverse response whose sign reverses with crystal chirality. The extracted cross-axial nonlinear susceptibility, $ \chi_{yxz}$ , exceeds the in-plane susceptibility, $ \chi_{xxx}$ , by more than two-folds, indicating a strong BCD-driven contribution. First-principles calculations attribute this behavior to a topologically nontrivial hedgehog-like BC texture near the H points and predict a BCD that reverses sign between opposite enantiomers, consistent with experiment. These results establish cross-axial nonlinear Hall transport as a symmetry-selective probe of chirality-controlled quantum geometry in tellurium and related chiral materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Atoms that Matter: Largest Materials Datasets Are 99% Redundant, and Local Chemistry Can Guide the Required 1%
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Evgeny Moerman, Igor Poltavsky, Anton Charkin-Gorbulin, Alexandre Tkatchenko
General-purpose machine-learning force fields (MLFFs) for materials are now trained on the order of $ 100$ million structures, assuming transferability requires such scale. We test this premise on OMat24, the largest available materials dataset, by training MACE models on subsets of $ 6.5$ million atoms, less than $ 1%$ of OMat24, selected in three complementary ways: at random, by latent-space clustering of a pretrained MLFF (DIRECT), and by a new model-free method maximizing the diversity of discrete, interpretable local environments (EnvTok). All three models approach the full-data reference MACE-OMAT-0 model to within a few tens of $ \mathrm{meV}/\mathring{\mathrm{A}}$ in forces, and remain close to or exceed it on formation energies, elastic moduli, heat capacities, Li$ ^{+}$ migration barriers, and molecular-dynamics stability up to $ 3000,$ K and $ 500,$ GPa. This near-independence from the selection strategy shows that chemical environment diversity, not size, defines OMat24’s information content: the remaining $ 99%$ of structures are largely redundant. Broad sampling of chemical space thus remains essential, but reference labels are needed only for structurally and chemically distinct configurations. Using atomic positions and species, optionally augmented by magnetic moments, EnvTok identifies these before any labelling or training, yielding compact, architecture-independent datasets. This hundredfold reduction makes hybrid-DFT or higher-level relabelling of general-purpose training sets feasible, and frees computational budget for extending environmental coverage and multi-fidelity learning.
Materials Science (cond-mat.mtrl-sci)
13 pages (+ 11 pages supplementary), 5+6 figures
Biomolecular condensates and their pathologies: A colloidal, interfacial, and transport perspective
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Vineeth Godavarti, Vinny Chandran Suja
Biomolecular condensates are micron-scale, membraneless compartments that concentrate proteins and nucleic acids by liquid-liquid phase separation (LLPS). Condensates play critical roles in transcription, mRNA metabolism, stress responses, and signaling across the cell, with their dysregulation increasingly correlated with several pathologies spanning neurodegeneration, cancer, cardiometabolic disease, and viral infections. The emergent biology of condensates can be cohesively viewed through the framework of colloidal, interfacial, and transport phenomena. Here we review the condensate literature through this joint lens, treating each condensate as a biological colloid whose behavior is captured by four measurable physical quantities: a Flory–Huggins interaction parameter that determines whether the dense phase forms at all, a partition coefficient that dictates the degree of client molecule accumulation, a viscoelastic relaxation time that sets whether the dense phase responds as a liquid or a solid, and an interfacial tension that governs droplet shape and interfacial dynamics. Each quantity is traced to its physical origin, its measured range in biological condensates, and the techniques that quantify it, for both three-dimensional droplets and two-dimensional membrane-tethered condensates. Interpreting disease as the displacement of these physical quantities from their functional ranges, we reorganize condensate pathologies into a small set of physical failure modes — saturation concentration dysregulation, aberrant aging and liquid-to-solid transitions, disrupted partitioning, interfacial aggregation, and pathogen hijacking — and show how the same parameters become design variables for condensate-targeted drugs and engineered coacervate delivery vehicles. The review concludes with open questions at the interface of condensate biology and colloidal and interfacial science.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
22 pages, 4 figures
Pre-pairing and polarization of doped charge carriers in unconventional superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Lixin Zhang, Mengyan Nie, Yan Cheng, Ran Zhao
Based on first principles calculations, we show in hole-doped La2-xSrxCuO4, the Sr dopants prefer to form dimers, rather than be isolated as generally believed. Same trend applies to other superconductors such as Na-doped Ca2CuO2Cl2, and electron type Nd2-xCexCuO4. The dimer structure makes the two doped holes (electrons) bound up and form a singlet which is also polarized. Another type of dopant in cuprates is oxygen which behaves similarly. So, we propose that, for all oxide high TC superconductors, the holes (electrons) are pre-paired (Z-pairs) during the preparation of the superconductor. The spontaneously formed Z-pairs are conceptually different from not only the Cooper pairs, but also the Zhang-Rice singlets. The attraction force in a Z-pair originates basically from the strong antiferromagnetic exchange energy. We also found that the on-site Coulomb repulsion (U) is no longer a constant due to doping. Around a doping site, U can reduce its value discontinuously, which plays a key role in stabilizing the Z-pairs against isolated holes (electrons). A Z-pair is a p-wave like localized state which breaks the symmetry of the CuO2 plain and attracts each other along the direction perpendicular to the polarization. The Z-pairs may be popular in all of the unconventional superconductors and the periodic assembly can result in the emergence of coherence states and superconductivity.
Superconductivity (cond-mat.supr-con)
15 pages, four figures
Transport kinetics in excitonic Mott insulator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
W. J. Brunner, Zhiwen Zhou, Luc M. Nguyen, C. A. Lozano, G. Mercado, L. H. Fowler-Gerace, L. V. Butov
Indirect excitons (IXs) in a periodic moiré potential in a van der Waals heterostructure form an experimental platform for exploring Bose-Hubbard physics, including the superfluid state and the Mott insulator state. The realization of these collective states requires low-disorder materials. In particular, the localization due to the Mott insulator must be distinguished from disorder-induced localization. We studied the transport kinetics of IXs in a MoSe$ _2$ /WSe$ _2$ van der Waals heterostructure with an anomalously high IX mobility, consistent with superfluidity. This high-mobility transport demonstrates that disorder-induced localization is negligible. We found a remarkable suppression of this efficient IX transport, directly indicating the Mott insulator. As the IX density increases during the excitation pulse, the IX cloud initially expands and then contracts upon entering the Mott insulator phase. The emergence of IX cloud contraction is accompanied by a peak in the IX spatial distribution at the origin. Our simulations reproduce the observed non-monotonic IX transport kinetics, including the temporal expansion and contraction of the IX cloud, as well as the peak in its spatial distribution.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Large Out-of-plane Polarization in Two-dimensional Bi2O3 Monolayers Predicted by an AI-driven Inverse-design Workflow
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Hongmei Tan, Jing Zhang, Shan Gao, Yueyu Zhang, Xiangmei Duan
Two-dimensional (2D) polar oxides with built-in electric fields offer promising opportunities for nanoscale electronics, optoelectronics, and surface charge engineering. However, their discovery remains challenging due to the enormous structural complexity of nonlayered oxide networks. Here, we combine inverse structural design with a machine-learning interatomic potential and first-principles calculations to explore 2D oxide configurations. Using Bi2O3 as a representative system, we identify two previously unreported polar monolayers with tetragonal and orthorhombic symmetries. Both structures exhibit vertically separated Bi and O sublayers, giving rise to pronounced intrinsic polarity with Berry-phase 2D polarizations of 34.12 and 37.15 pC/m, respectively. Notably, the o-Bi2O3 monolayer exhibits one of the largest reported out-of-plane polarizations among 2D oxides. Both monolayers exhibit dynamical stability, finite-temperature structural integrity, and wide band gaps (~3.8 eV). The large polarization originates from dimensionality-induced reconstruction of the nonlayered Bi-O network, which breaks local coordination symmetry and produces out-of-plane charge redistribution, while the stereochemically active Bi 6s2 lone pair further favors asymmetric Bi-O bonding. These findings suggest dimensionality-induced local-coordination symmetry breaking as a promising design motif for high-polarization 2D oxides, and demonstrate the utility of combining inverse design with machine-learning-assisted screening to explore unconventional polar phases in nonlayered oxide networks.
Materials Science (cond-mat.mtrl-sci)
23 pages, 6 figures
Fluctuation-based evaluation of thermal conductivity using deviational phonon Monte Carlo simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
We develop a fluctuation based Monte Carlo method for evaluating thermal conductivity within the phonon Boltzmann transport equation (BTE) framework. Starting from the energy based variance reduced formulation of the BTE, we derive a relation between the spatial spreading of deviational phonon energy and the macroscopic heat conduction equation. The resulting formulation expresses thermal conductivity in terms of the mean square displacement of deviational phonon particles, without imposing thermal reservoirs. Consequently, thermal conductivity along multiple directions can be evaluated from a single simulation. The method is demonstrated for crystalline silicon at room temperature in bulk, square nanowires, and anisotropic polycrystalline nanostructures. The calculated thermal conductivities agree with theoretical predictions, including the size dependence induced by phonon boundary scattering and the mode-resolved contributions. For anisotropic polycrystalline structures, the method simultaneously resolves the directional thermal conductivities and captures their dependence on grain morphology. These results demonstrate the validity of the proposed fluctuation-based approach for evaluating thermal conductivity across different transport regimes and structural configurations.
Materials Science (cond-mat.mtrl-sci)
Soft-to-Rigid: Shape Continuation as an Alternative Search for Packing Congruent Shapes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Searches for dense packings of congruent shapes move rigid pieces. Hardening starts each piece as its inscribed disk and deforms it into the target shape while the container is compressed. We ask whether it is a search worth running alongside existing ones, and test it at matched budget and comparable tuning against rigid starts, growth, simulated annealing and perturbation–compression on seven families of squares, triangles, hexagons and disks in squares, triangles and circles (188 instances), scoring each method by the lowest container size it reaches. Hardening is not a better default: tuned rigid starts reach the lowest size most often. It is a different search. On squares in a square it reaches packings the other four methods miss, including Trump’s n = 11 and Wainwright’s n = 19 in 32 runs per method, and in a targeted follow-up campaign at ten times the budget (16 runs per method) it is the only one to reach the best known packings for n = 17 and n = 26, while annealing alone reaches n = 27. In exploratory ablations, compressing disks and then switching to polygons at once, or growing rigid polygons along hardening’s area schedule, shows no detectable difference from rigid starts, and hardening’s unique packings contain more tilted pieces. The bias costs elsewhere: hardening is worse on triangles and on four families held out from all development, where the short-pilot policy we tested showed no detected advantage over always starting rigid. Shape continuation is an alternative search that reaches different packings, worth keeping beside rigid ones; we did not show that splitting a fixed budget between them pays, and we have no test that predicts where it helps. Search campaigns were planned before they ran, with amendments, exploratory analyses and post-hoc checks identified separately; every run is replayable and every number is generated from an event log.
Soft Condensed Matter (cond-mat.soft)
21 pages, 5 figures, 11 tables. Code, data, every run, replays and the research ledger: this https URL ; site: this https URL
Quantum Geometry and Pair Breaking in Intra- and Intervalley Superconductivity of Rhombohedral Graphene
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Louis Primeau, Yang Zhang, Shi-Zeng Lin
The observation of superconductivity emerging from a spin- and valley-polarized normal state in rhombohedral graphene raises a basic puzzle: intravalley Cooper pairs involve states that are not generically degenerate because of trigonal warping, and therefore lack the particle–particle nesting underlying the conventional Cooper instability. While recent model studies suggest that nontrivial band geometry can strongly promote chiral pairing, how this geometric enhancement competes with realistic band-structure-induced pair breaking remains unclear. Here we study Kohn–Luttinger superconductivity in electron-doped rhombohedral tetralayer graphene using a DFT-fitted multiorbital tight-binding model, retaining the full Bloch-wave-function form factors in both RPA screening and the projected Cooper interaction. We separate the superconducting instability into three contributions: the symmetry-resolved form-factor-dressed interaction, the Cooper-pair phase space determined by the symmetrized pair dispersion, and the energy mismatch generated by trigonal warping. We find that the Bloch form factors strongly favor intravalley pairing, with a leading predominantly $ p_x-ip_y$ instability and a substantially larger maximum $ T_c$ than the intervalley reference state. At the same time, trigonal-warping-induced mismatch cuts off the Cooper logarithm and confines intravalley superconductivity to a much narrower region of the phase diagram. The dominant instability occurs near pair-Lifshitz transitions and primarily in reconstructed annular or three-lobed Fermi-surface regimes. Our results show that superconductivity in rhombohedral graphene is controlled by the combined effects of quantum-geometry-dressed interactions, pair fermiology, and trigonal-warping-induced pair breaking.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
31 pages, 5 figures
Exotic metallic phase in a heterotic Kondo lattice: violation of Luttinger’s theorem and absence of Kondo gap
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Hanting Zhong, Shuxiang Yang, Chao Cao, Xiao-Yong Feng, Jianhui Dai, Hai-Qing Lin
Fermi surface transformation accompanied by quantum phase transition is widely observed in correlated electron systems including heavy fermion materials and van der Waals quantum heterostructures. The unified Anderson lattice description for this phenomenon suggests that their interacting ground states in the case of electron half filling always destabilize the metallic phase in the strong Kondo-coupling regime. We examine this issue within the paramagnetic phase of a Kondo lattice system with a heterotic layered structure. In the weak Kondo-coupling regime, the system exhibits a fractional Dirac liquid involving the massless or massive Dirac fermions and a charge neutral spinon Fermi surface. In the strong Kondo-coupling regime, the spinons hybridize with the Dirac fermions resulting in an intermediate nearly-flat hybridizing band together with the conduction and valence heavy fermion bands, yielding a large electric Fermi surface. Absence of the Kondo gap between these bands is observed depending on the stacking configurations of the layered structure. In particular, the system remains metallic even at the exact half filling in this regime and Luttinger’s theorem is violated across the critical point. Implications of these results on the van der Waals quantum heterostructures are briefly discussed.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 6 figures
Optoelectronically Enabled Simultaneous and Decoupled Navigation and Selective Pairing of Electrically Driven Janus Particles for Multi-Agent Microrobotics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Srikanta Debata, Ido Rachbuch, Gilad Yossifon
Self-propelled Janus particles are promising active agents for microscale manipulation and microrobotic applications. However, when powered by a global external energy source, such as an electric, magnetic, or optical field, all particles respond simultaneously, preventing their independent and concurrent control. Achieving parallel, decoupled control without continuous particle-specific feedback, while preserving intrinsic self-propulsion, remains a significant challenge. Here, we present an optoelectronic (OE) strategy for simultaneously and independently controlling electrically driven, self-propelled metallo-dielectric Janus particles (JPs) using spatially programmable virtual electrodes. These electrodes are generated by projecting a single predefined illumination pattern from a digital micromirror device onto a photoconductive surface. The resulting confinement landscape enables multiple JPs to follow distinct trajectories without continuous monitoring, feedback, or pattern reconfiguration. We demonstrate controlled pairing of JPs with passive polystyrene particles and biological cells. For automated multi-agent operation, an image-based assignment framework identifies optimal agent-target pairs, excludes intersecting trajectories, and generates a single composite pattern for simultaneous, selective pair formation without real-time updating. Finally, we demonstrate independent manipulation of multiple magnetically rolling JPs under a globally applied magnetic field. Overall, this programmable open-loop strategy provides a versatile framework for multi-agent microrobotic manipulation, with potential applications in in-vitro micromanipulation and microfluidic systems.
Soft Condensed Matter (cond-mat.soft)
Surface Granular flows: Two Related Examples
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Devang V. Khakhar, Ashish V. Orpe
Granular surface flows are common in industrial practice and natural systems, however, theoretical description of such flows is at present incomplete. Two prototype systems involving surface flow are compared: heap formation by pouring at a point and rotating cylinders. Continuum models for analysis of these flows are reviewed, and experimental results for quasi-2d systems are presented. Experimental results in both systems are well described by continuum models.
Soft Condensed Matter (cond-mat.soft)
Advances in Complex Systems, Vol. 4, No. 4 (2001) 407-417
A Fisher-Geometric Approach to Supercell Pair Distribution Function Refinement
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Refining atomistic supercells against powder pair distribution functions (PDFs) requires optimizing many coupled atomic coordinates using a much smaller set of radial measurements. Reverse-mode differentiation makes gradients accessible for large systems, but standard first-order optimizers do not explicitly use coupled PDF sensitivities to precondition coordinate updates. We introduce a matrix-free, Fisher-geometric approach that pulls the information metric of the observation likelihood back onto atomic coordinates. The resulting update weights collective displacements according to their PDF response and experimental uncertainty. Under isotropic damping, the update is obtained by solving a damped linear system over $ M$ PDF channels, using automatic differentiation to evaluate Jacobian–vector and vector–Jacobian products without constructing the full Jacobian or coordinate curvature matrix. For Gaussian measurement errors, the update recovers classical Levenberg–Marquardt refinement while avoiding dense coordinate-space factorization. The same computational framework accommodates correlated Gaussian errors and robust likelihood-based updates. This approach combines likelihood-aware collective updates with matrix-free backpropagation for direct second-order refinement of large atomistic supercells.
Materials Science (cond-mat.mtrl-sci)
Enhancing Quasi-Two-Dimensional Electronic Structure in Bi2O2Se via Chlorine Substitution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Yong-Zhen Jiang, Qi-Xun Wen, Xiang Xu, Su-Tao Sun, Feng-Fan Ren, Zi-Xuan Zhou, Xing-Yuan You, Yu-Cheng Kan, Zheng Zhang, Jie-Yi Liu, Yu-Zhou Zhao, Zheng-Tai Liu, Mao Ye, Shu-Hua Yao, Jian Zhou, Yan-Bin Chen, Zhong-Kai Liu, Yu-Lin Chen, Yang-Yang Lv, Cheng Chen
Bismuth oxyselenide (Bi2O2Se) has emerged as a leading semiconductor candidate for next-generation electronics and quantum phenomena research. However, its strong ionic interlayer bonding of Se layers fundamentally restricts the full potential of this otherwise promising quasi-two-dimensional (2D) material. In this work, we demonstrate chlorine substitution as an effective strategy to introduce van der Waals gaps and modify the electronic structure of the system. Through comprehensive transport and angle-resolved photoemission spectroscopy (ARPES) measurements on Bi6O6Se2Cl2 single crystal, an optimal Cl-doping compound, we show that the key electronic features, including indirect band gap, high electron mobility, and carrier effective mass, are well preserved, while the 2D character of the system is sufficiently enhanced. First-principles calculations attribute this selective tunability to the unique spatial separation between conductive Bi-O layers and dopant Se/Cl layers, which enables independent optimization of interlayer coupling and intralayer transport. Remarkably, our theoretical calculations combined with experimental observations project a broad bandgap engineering across a wide range (0.8 ~ 3.5 eV) within the Bi2O2Se system. Our findings not only expand the application potential of Bi2O2Se-based materials in optoelectronics, nanoelectronics, and fundamental research but also highlight spatial decoupling as a viable strategy for modifying detailed electronic structure of quasi-2D quantum systems.
Materials Science (cond-mat.mtrl-sci)
5 figures, 1 table
Advanced Science (2026): e77919
Chemical-Potential-Dependent Superconducting Spectroscopy on Bi2Te3/NbSe2 Heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Pengyu Hu, Chun Yu Wan, Qiaoyan Yu, Chen Qian, Yisheng Gu, Xian Du, Xuhui Ning, Tingwen Miao, Shi Chen, Zihao Ma, Hao Yang, Hemian Yi, Weijiong Chen, Xiaoxue Liu, Liang Liu, Dandan Guan, Yaoyi Li, Shiyong Wang, Canhua Liu, Sangen Zhao, Fulin Wang, Junwei Liu, Hao Zheng, Jinfeng Jia
High-resolution scanning tunneling spectroscopy performed at dilution refrigerator temperatures was employed to investigate the superconducting properties of topological insulator/superconductor (Bi2Te3/NbSe2) heterostructures. Coherence peaks with inner kinks or inner peaks, deviating from the conventional single s-wave spectral line shape, were observed in both 5 quintuple-layer (5QL) and 7QL Bi2Te3 thin films. Based on the combination of chemical-potential-dependent spectroscopic measurements and model simulations, we conclude that these spectral features arise from contributions of bulk and surface states in Bi2Te3 by selectively proximity-coupled to a single superconducting gap from NbSe2, rather than inheriting the complicated superconductor’s order parameter of NbSe2.
Superconductivity (cond-mat.supr-con)
16 pages
Magnon Klein paradox
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
By considering the energy transport of spin wave, we show that, like the electron Klein paradox, there is no magnon Klein paradox for reflectivity. Heuristically, this can be understood according to the fact that, even if the ground state is unstable, any energy-carrying wave cannot have greater-than-one reflectivity off a passive interface, which will violate the conservation of energy. The magnon Klein paradox discussed in the literature is derived from assigning a wrong sign to the transmitted spin wave.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
3 figures
Crossed Electric Spin Generation in Multilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Xukun Feng, Wei Du, Jin Cao, Qian Niu, Shengyuan A. Yang, Cong Xiao
We propose a crossed electric spin generation effect in multilayer structures. This effect combines the advantages of in-plane and gate electric fields for manipulating spin, and unveils a nice quantum geometric structure in terms of the underlying hybrid Berry curvatures that are unique to quasi-2D systems and manifest inherent spin-layer-orbital coupling. Combining our theory with first-principles calculations, we predict sizable spin generation in 2D ferromagnetic Fe3GeTe2 and altermagnetic V2Te2O. Our theory opens a new Berry-curvature route for all-electric spin manipulation in 2D materials
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Finite-temperature adiabatic-connection reduced density-matrix functional theory: a unified framework for i-DMFT and TAO-DFT
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Jingang Han, Huanjing Gong, Kai Luo, Hongming Weng, Xinguo Ren
Accurately describing chemical bond breaking requires capturing strong/static electron correlation, a major challenge for single-reference self-consistent-field methods such as Hartree–Fock and Kohn–Sham density-functional theory (DFT). Fractional occupations substantially improve this situation, as demonstrated by information-density-matrix-functional theory (i-DMFT) and thermally-assisted-occupation DFT (TAO-DFT). Although useful, they are formulated within rather different theoretical frameworks, are somewhat semi-empirical, and their relationship remains unclear. Here we introduce finite-temperature adiabatic-connection reduced density-matrix functional theory (FT-AC-RDMFT), in which i-DMFT and TAO-DFT emerge as different reductions of a unified framework. The effective eigenvalue equation for natural orbitals and the Fermi–Dirac occupation numbers follow directly from the variational principle, while a thermal adiabatic connection relates the empirical entropy coefficient of i-DMFT to a characteristic temperature of the auxiliary non-interacting system. Within this framework, i-DMFT is the exact-exchange-based reduction, whereas TAO-DFT results when exact exchange is replaced by a density-based exchange-correlation functional. Numerical calculations confirm that i-DMFT, apart from a constant, coincides with the exact-exchange realization of the framework, and show that the improved dissociation behavior from finite-temperature occupations extends beyond exact exchange to hybrid and semilocal density functionals. For strongly correlated V2O3, finite-temperature occupations substantially reduce the severely overestimated non-magnetic LDA bulk modulus, bringing it close to experiment. These results establish FT-AC-RDMFT as a common theoretical foundation for finite-temperature occupation-based electronic-structure methods in molecular and solid-state systems.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Kink boundary-induced polarity revealed by nonreciprocal charge transport in FeTe0.7Se0.3 superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Shengyao Li, Ya Deng, Han Yan, Dianyi Hu, Zherui Yang, Xueyan Wang, Ming Yue, Qiong Wu, Zheng Liu, X. Renshaw Wang
Nonreciprocal charge transport, characterized by direction-dependent electrical response, provides a powerful probe of electronic structure and a platform for rectification. However, its realization is typically governed by intrinsic crystal symmetry, restricting the range of suitable materials. Here, we demonstrate nonreciprocal charge transport in an otherwise centrosymmetric superconductor, FeTe0.7Se0.3 (FTS), through kink boundary-induced strain engineering. The stress relaxation during growth generates a cusp-like kink-band boundary with asymmetric curvature, producing a spatially nonuniform strain field and an effective in-plane polarity that breaks inversion symmetry. Pronounced nonreciprocal transport is observed under out-of-plane magnetic fields, with strong dependence on current and temperature across the superconducting transition, in contrast to the negligible response in flat nanosheets. Our results identify kink boundary-induced symmetry breaking as a general route to engineer nonreciprocal charge transport in centrosymmetric systems.
Superconductivity (cond-mat.supr-con)
Inverse Designing Reconfigurable Piezoelectric Tensors via Architectural and Modal Programming
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Anish Satpati, Marco Maurizi, Hyunmoon Cho, Victor Couedel, Nicolas Mule, Xiaoyu (Rayne)Zheng
Piezoelectricity arises from the coupling between electric polarization and mechanical deformation, described by a third-rank tensor whose coefficients are constrained by crystal symmetry. In natural crystals, atomic periodicity and energetic stability restrict accessible symmetries, limited to 20 distinct anisotropies that can exist. Here we establish a general framework, based on graph representation, for controlling the full effective piezoelectric tensor through architecture by resolving how macroscopic symmetry, local polarization and deformation of structural elements act together. This enables each coefficient to be traced to the members that reinforce or cancel it and be controlled through targeted geometric changes. We further uncover frequency-selective tensor reconfiguration, in which excitation frequency switches the dominant piezoelectric coefficients of a single architecture. These principles open a broader class of applications in which a single piezoelectric architecture can deliver programmable sensing, actuation and mode conversion across multiple directions and deformation states. We realize a multi-degree-of-freedom actuator that integrates distinct actuation modes in one block and reduces volume by 90% relative to conventional multi-stack assemblies.
Materials Science (cond-mat.mtrl-sci)
Driven Vortex Motion in Periodic Channel Potential Embedded in Superconducting Films
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
A. Al Luhaibi, A. Glatz, Michael Vogl, Hocine Bahlouli, J. B. Ketterson
In this paper, we investigate vortex dynamics in periodically width-modulated superconducting channels by numerically solving the time-dependent Ginzburg-Landau (TDGL) equations. The channels are designed with sinusoidally varying widths characterized by their average width and modulation amplitude. The motion of driven vortices generates an oscillatory electric field with a fundamental frequency, $ f_0$ , set by the channel periodicity, together with higher-order harmonics. In contrast to the situation of vortex lattice dynamics in a periodic pinning landscape of circular holes considered by Al Luhaibi et al. [1], we show that the harmonic content of the generated electric field can be effectively controlled through the channel geometry. In particular, appropriately engineered channel profiles strongly suppress higher-order harmonics, yielding an electric-field response that closely approaches a pure sinusoidal waveform. These results demonstrate that geometric modulation offers a viable route to engineering low-harmonicity microwave signals in superconducting devices and may enable cryogenic on-chip waveform generators for controlling superconducting qubits. Such devices could provide a useful building block for scalable transmon-based quantum computing architectures.
Superconductivity (cond-mat.supr-con)
Active remodeling rescues a microswimmer from geometric trapping
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Ayushi Bhatt, Nico Schramma, Jasper van der Gucht, Uddalok Sen
Natural habitats confront microorganisms with heterogeneous, mechanically complex surroundings that shape how they move and explore. Most studies of motility in complex media treat the environment as either a homogeneous fluid or a rigid obstacle field. Here we instead study a medium that is simultaneously soft and reconfigurable — deformable by the organism moving through it. We track the unicellular biflagellate microalga \emph{Chlamydomonas reinhardtii} swimming in a soft, disordered suspension of microgel particles comparable in size to the cell itself, across a range of gel packing fractions. With increasing packing fraction, trajectories change from long straight runs to short, frequently reorienting ones, and the effective translational diffusivity decreases monotonically. The bimodal run/tumble speed distribution, characteristic of the free-swimming gait, collapses toward a single mode as the packing fraction increases, by near-proportional slowing of both gait states rather than a redistribution of cells between them. Recasting trajectories as alternating hops and traps reveals the signature of a deformable medium: hop lengths halve as the gel densifies, approaching the microgel aggregate scale, while trapping times do not increase with increasing packing fraction. Independent force estimates place the cell’s propulsive force close to an order of magnitude above that needed to deform a single grain, so remodeling is expected rather than merely observed. A minimal \emph{active remodeler} model — an active Brownian particle among mobile, rigid obstacles — shows that obstacle mobility alone is sufficient to relocate the onset of permanent trapping. Thus, our results establish obstacle mobility as a control parameter for motility in soft, disordered matter.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Selective faceting induced by Hexagonal Boron Nitride on curved Platinum substrate
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Alaa Mohammed Idris Bakhit, Muhammad Saad Mahmood, Khadiza Ali, Anna A. Makarova, Igor Piš, Federica Bondino, Frederik Schiller, Maria Peressi
This work combines experimental investigations and first-principles calculations to study hexagonal boron nitride (hBN) growth on a curved Pt(331) substrate. Low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM) were employed to investigate the structural properties, observing that hBN growth led to faceting with several stable facets: Pt(111), Pt(221), Pt(441), Pt(881), and Pt(110). Additionally, the electronic properties were examined by X-ray photoemission spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS), revealing an increase in the hBN-substrate interaction strength, from the weakest at the Pt(111) to the strongest at the Pt(110). Density functional theory (DFT) calculations confirm that the selective faceting mechanism is induced by hBN, which changes the order of relative stability of the uncovered facets. Although a complete understanding of the process is not achievable using only thermodynamical arguments, the comparison between hBN adhesion energies and clean surface free energies clearly indicates that some facets are stabilized with respect to others by stronger overlayer-substrate interaction, whereas for others the clean surface energetics plays the dominant role.
Materials Science (cond-mat.mtrl-sci)
14 pages, 8 figures
Emergent one-dimensional Bloch oscillations in coupled Ising layers
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Bloch oscillations typically arise in periodic systems subjected to a constant force generated by a potential gradient. Here, we study domain-wall dynamics in coupled Ising layers under asymmetric longitudinal fields. The interlayer coupling is of Heisenberg type and acts as an effective transverse coupling in the emergent pseudospin representation. We show that the rung pseudospin structure gives rise to kinetic constraints, restricting the many-body dynamics to an emergent one-dimensional quasiparticle subspace within the original two-dimensional system. Furthermore, the imbalance between the longitudinal fields of the two layers induces an effective linear potential for the emergent domain-wall excitations, leading to their confinement between two oppositely polarized ferromagnetic domains. Remarkably, the resulting Wannier–Stark ladder of domain-wall excitations gives rise to Bloch oscillations in the absence of a conventional tilted potential, revealing a distinct mechanism for coherent quantum dynamics. Numerical simulations of time-dependent observables confirm the analytical predictions.
Strongly Correlated Electrons (cond-mat.str-el)
A Higher-Order Stroh Framework for Weakly Nonlinear Post-Bifurcation Analysis
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Shiyuan Deng, Han Ye, Yafei Wang, Lizichen Chen, Alain Goriely, Yibin Fu, Weiqiu Chen, Chaofeng Lü, Michel Destrade, Kecheng Li, Yangkun Du
Linear stability analysis predicts the onset of wrinkling, while weakly nonlinear analysis determines whether the bifurcation is supercritical or subcritical through the sign of the cubic amplitude coefficient. When this coefficient vanishes, higher-order terms are needed. In this paper, we develop a higher-order Stroh framework for weakly nonlinear post-bifurcation analysis of finitely deformed elastic solids. For each nonzero harmonic, the same base-state Stroh operator is retained at every order, with nonlinear source terms assembled from lower-order fields to account for geometry, constitutive laws and constraints. This recursive structure, together with Fredholm solvability conditions, enables us to derive cubic, quintic and higher-order amplitude equations. Here, we demonstrate the power of this framework by analysing wrinkling in an incompressible neo-Hookean film bonded to an exponentially graded substrate. The results recover established linear instability benchmarks and the supercritical-subcritical transition in the homogeneous-substrate limit. For graded substrates, the cubic coefficient vanishes on a surface in the parameter space of modulus ratio and substrate gradation. On this surface, the quintic coefficient takes both signs, corresponding to supercritical and subcritical bifurcations. These regions are separated by a curve along which the quintic coefficient also vanishes. Determining the branch direction along this curve requires higher-order terms, which can be calculated within the same framework.
Soft Condensed Matter (cond-mat.soft)
Pressure-transferable universal machine-learning potentials: the WBM-MatPES benchmark and Tuga-FF
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Pierre-Paul De Breuck, Thalis H. B. da Silva, Antoine Loew, Silvana Botti, Miguel A. L. Marques
Universal machine-learning interatomic potentials hold the promise to replace costly ab initio calculations in materials science workflows. However, the accuracy and transferability of current models are limited by the availability of training data. We release WBM-MatPES, a dataset of 182 thousand structures recomputed with consistent MatPES settings, together with two reference convex hulls of different depths and test sets at six pressures up to 150 GPa. These datasets reproduce a realistic discovery workflow and allow potentials to be ranked systematically at this level of theory, similar to the Matbench Discovery leaderboard at the Materials Project settings. In this benchmark, five published MatPES potentials agree within 12 meV/atom at 25 GPa, yet their errors increase dramatically to 0.4-5 eV/atom at 150 GPa. To address this limitation, we develop Tuga-FF, a graph transformer trained on datasets spanning ambient and high-pressure configurations alike. Tuga-FF is the most accurate model in the benchmark at ambient pressure, with an energy error of 13.6 meV/atom, and maintains an error of just 21 meV/atom at 150 GPa. We believe this benchmark will encourage the community to train higher-accuracy models and generate richer datasets, advancing machine-learned interatomic potentials as a whole.
Materials Science (cond-mat.mtrl-sci)
17 Pages, 4 figures, 6 tables
Spiral Edge States in Topological 2D Sb2Te3 Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Timothy Carlson, Daniel Lazega, Scott McGuire, Mihirangi Medahinne, Motahhare Mirhosseini, Gabriel Marcus, ChaoChao Dun, Maria Kolesnik-Gray, Vojislav Krstic, David Carroll
This work explores the edge state conduction properties of twinned and spiraled, 2D Sb2Te3 topological insulator crystals. We show the structure supports spatially continuous edge states within two spiral and knotted edge conduction channels. The channels are connected through a topological defect. This geometry introduces boundary conditions into the 2D crystal that modifies the edge state dispersion. Using a combination of low loss Electron Energy Loss Spectroscopy, Magnetic Force Microscopy and traditional carrier transport measurements we identify a distinct excitation at 0.155 eV in the spiral that seems to be related to two isolated states within the gap. This state is localized to the crystal edges. The modification of edge state bands using manipulation of a systems quantum geometry may open new avenues for the use of 2D topological systems.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Pressure-Driven Evolution of the Physical Properties of Layered Y2GaB and Y2InB MAB Phases: A Comparative First-Principles Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
M. Rabi Us Sani Shapon, Md. Asif Afzal, Jubair Hossan Abir, Raihana Shams Islam, Saleh Hasan Naqib
MAB phases are nanolaminated ternary borides in which strong in-plane M-B bonds and weaker interlayer interactions drive their distinctive stability and functionality. Hydrostatic pressure offers a direct route to tune the in-plane and interlayer interactions that govern the stability and functionality of layered Y2GaB and Y2InB borides. Here, first-principles calculations are used to compare their structural, elastic, thermophysical, electronic, bonding, optical, and vibrational responses from 0 to 20 GPa. Elastic criteria show that Y2GaB is stable at 0, 5, and 10 GPa, whereas Y2InB is stable only at ambient pressure. Within the stable Y2GaB range, compression increases the elastic moduli, acoustic velocities, Debye temperature, and lattice thermal conductivity while reducing the elastic anisotropy. Both compounds are multiband metals and spin-orbit coupling modifies local dispersions without opening a gap. Y2GaB retains nine Fermi-surface sheets from 0 to 10 GPa, whereas Y2InB has eight at ambient pressure, with no pressure-induced topological reconstruction. Charge-density and overlap analyses indicate mixed ionic-covalent Y-B bonding within a delocalized metallic background. Optical parameters are anisotropic. Unit-cell phonon spectra contain positive frequencies at 0 and 10 GPa, although expanded-supercell calculations reveal low-frequency sensitivity. These results establish mechanically viable pressure windows and clarify substitution-driven structure-property relationships for these borides.
Materials Science (cond-mat.mtrl-sci)
Investigation on Thermal Stability of Epi-GeSn Directly on Si (001)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Tharundev V V, Dushyant Singh, Vigneshswari SR, Subha Maity, Prince Rathor, Krista R Khiangte
In this paper we investigate the structural properties and thermal stability of metastable Ge1-xSnx epilayers (~4.5 at.% Sn) grown directly on Si(001) substrates by high-resolution X-ray diffraction (HRXRD) and Raman spectroscopy. Our results demonstrate that both 70 and 140 nm films are fully relaxed, with the thicker film exhibiting a small tensile strain (+0.09%). The thermal stability of the heterostructures was evaluated up to 813 K using temperature-dependent Raman spectroscopy and scanning electron microscopy. The surface-weighted Raman response (532 nm excitation) and surface morphology of the 70 nm film remain highly stable. In contrast, the 140 nm film undergoes severe degradation, characterized by significant attenuation and broadening of the Ge-Ge longitudinal optical phonon mode, alongside enhanced surface Sn segregation. These findings demonstrate that the thermal stability of direct GeSn/Si heterostructures is governed by the initial defect structure established during epitaxial growth, providing key design rules for understanding the fabrication of GeSn-based optoelectronic devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
A Minimal Theoretical Model for Morphodynamic Selection in Soft Matter Systems
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Soft matter systems often display shape transitions, mode competition, and threshold-like dynamical responses driven by the coupling between mechanics, geometry, and biochemical or active fields. Here we present a minimal theoretical framework for describing such morphodynamic selection using a small number of physically interpretable order parameters. The model combines elastic relaxation, active driving, and nonlinear feedback, yielding distinct regimes corresponding to weak deformation, single-mode selection, and coupled shape transformation. We derive the governing equations, identify the relevant dimensionless control parameters, and show how the phase behavior can be organized in terms of threshold competition and effective coupling strengths. The framework provides a compact route for connecting analytical theory, numerical simulations, and experimentally observable shape dynamics in soft and biological matter.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
17 pages, 4 figures
Time-temperature-composition equivalence of the viscoelastic behavior through the glass transition of digitally mixed 3D-printed polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Beijun Shen, Sanat K. Kumar, Mary C. Boyce
The linear viscoelastic behavior of a polymer shows an equivalence of loading frequency and temperature, the time-temperature equivalence (TTE). Horizontal shifting extends moduli measured over limited ranges to much wider ranges, through the glass transition. Multimaterial 3D printing has created digitally mixed polymers, a new class in which elastomeric and glassy resins are mixed voxel by voxel in prescribed ratios. Composition shifts the location and breadth of the glass transition and increases the rubbery modulus. Here we extend TTE to a time-temperature-composition equivalence (TTCE). Across all measured temperatures, frequencies, and compositions, the storage modulus collapses onto one master curve. Composition translates the transition and stretches its breadth, both linearly. The phase angle and relaxation spectrum superpose under the same operations, so the family shares one distribution of relaxation times. A single closed-form TTCE gives the storage and loss moduli of the family, guiding graded and architected designs for elasticity and dissipation.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
7 figures, 12 pages of main text
EpNet-Si: Atomic Form Factors Learned from Band Structures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
The empirical pseudopotential method (EPM) computes band structures with one diagonalization per $ k$ point and no self-consistency, but its fixed atomic form factors do not transfer between crystal structures. To address this limitation, we introduce EpNet-Si, an EPM for silicon in which an equivariant network predicts each atom’s plane-wave form factor from its local environment: a species potential plus monopole, dipole and quadrupole corrections, mixed by a learned router over atomic densities, together with an $ s/p$ nonlocal projector. With 6{,}195 parameters, the model is trained through the eigensolver on reference density functional theory (DFT) band energies of only 77 cells. Among 231 distortions of the trained structure types, the 142 gapped cells have mean band and gap errors of 15 and 8,meV; among 192 unseen structures, the 165 gapped cells have mean errors of 38 and 49,meV. Physical properties derived from EpNet-Si, including effective masses, gap pressure coefficients, deformation potentials and the density of states at the Fermi level, agree with those obtained from the reference DFT calculations. These results suggest that the classical EPM, fitted to a small set of reference data, can be extended into a fast alternative for modern electronic band-structure calculations.
Materials Science (cond-mat.mtrl-sci)
16 pages, 14 figures
DiffGA: Steering Frozen Diffusion Models for Materials Design via Evolutionary Search
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Shivang Agarwal, Rodrigo Wang, Kevin Ryczko, Aayush R. Singh
Steering candidate generation toward user-defined objectives is central to inverse materials design, yet remains difficult when objectives are black-box, changing, or non-differentiable, as in many simulation- and experiment-derived properties. Generative models offer a solution but typically require retraining or fine-tuning for each new objective, demanding labeled data and substantial compute, or rely on differentiable guidance that is brittle to gradient noise and undefined for many practical targets. We present DiffGA, a retraining-free framework that injects evolutionary search into the sampling trajectory of a retrained diffusion model, evolving partially denoised states under an arbitrary black-box oracle. Because oracle evaluation often dominates campaign cost, we couple DiffGA with an on-the-fly Bayesian surrogate that reuses representations from state-of-the-art machine-learned force fields (MLFFs). A Gaussian process is fit during the campaign on the force fields’s graph embeddings and, once it demonstrably ranks an unseen generation, replaces expensive property evaluations under an uncertainty-aware acquisition rule, reducing oracle cost with negligible loss of accuracy. Across three crystal-design tasks using a frozen MatterGen backbone, DiffGA outperforms diffusion-only, compute-matched, purely evolutionary, and fine-tuned baselines in oracle-assessed rates of stable, unique, and novel hits. Rather than proposing scientific compounds, we use density functional theory to quantify MLFF oracle fidelity, showing that it is a faithful proxy in key regimes but systematically biased in others, delineating when proxy-driven generative discovery can be trusted. On a representative sample, DiffGA’s top hits survive first principles re-evaluation as physically realistic hits, while the surrogate-accelerated pipeline preserves this fidelity at a fraction of the cost.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Graphene-Confined Growth of Few-Layer PtSe2 via One-Step Selenization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Timea Ema Krajčovičová, Peter Kotrusz, Viera Skákalová, Agáta Laurenčíková, Igor Píš, Martin Hulman, Kimmo Mustonen, Michaela Sojková
Platinum diselenide (PtSe$ _2$ ), a member of the transition metal dichalcogenide (TMD) family, is a promising material for next-generation electronic and optoelectronic applications due to its thickness-dependent properties, transitioning from semimetallic in bulk to semiconducting behavior at the few-layer limit. However, the scalable fabrication of large-area ultrathin PtSe$ _2$ films remains challenging, as conventional selenization of pre-deposited Pt layers often leads to undesired three-dimensional clustered growth. This work explores a novel strategy for promoting two-dimensional growth of PtSe$ _2$ by employing a graphene-mediated confinement approach. The method involves coating a Pt layer with graphene oxide (GO), followed by annealing in a selenium atmosphere, which results in the simultaneous formation of PtSe$ _2$ and the reduction of GO to graphene. The graphene overlayer acts as a physical confinement layer, suppressing vertical growth and enabling the synthesis of graphene-confined PtSe$ _2$ heterostructures on centimetre-scale substrates and promoting lateral connectivity of PtSe$ _2$ regions observed by STEM. Scanning transmission electron microscopy (STEM), including temperature-resolved in situ atomic-resolution measurements, was used to investigate the influence of selenization temperature on the growth mechanism and structural evolution of PtSe$ _2$ films. The results show that graphene confinement stabilizes lateral growth and promotes the formation of few-layer films with improved structural ordering. Beyond PtSe$ _2$ , this graphene-assisted approach provides a general strategy for fabricating and stabilizing ultrathin TMD layers, including those prone to environmental degradation, providing a new outlook for enabling detailed studies of their intrinsic properties.
Materials Science (cond-mat.mtrl-sci)
Role of defect trapping in the enhanced corrosion resistance of Ni-Mo alloys with yttrium and yttrium oxide additions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Jia-Hong Ke, Xinchang Zhang, Jingfan Yang, Qiufeng Yang, Ruchi Gakhar, Rongjie Song
Corrosion of structural alloys remains a critical challenge for advanced molten salt reactors, where aggressive fluoride salts promote continuous dissolution at the salt-metal interface. While most mitigation strategies emphasize thermodynamic stability, kinetic control of atomic transport has received comparatively less attention. Here, we propose a corrosion mitigation strategy based on diffusion control and vacancy trapping by dilute yttrium (Y) solutes and yttrium oxide (Y$ _2$ O$ _3$ ) dispersions in Ni alloys. A combined computational and experimental approach integrates density functional theory (DFT), self-consistent mean-field (SCMF) diffusion modeling, and an impurity trapping model to quantify the impact of defect trapping on effective vacancy mobility. Strong first-nearest-neighbor vacancy-Y binding, off-lattice vacancy configurations, and elevated rotational and dissociation barriers result in pronounced suppression of vacancy diffusivity, while Y$ _2$ O$ _3$ -associated sites treated as fixed traps in the model further reduce the mobile vacancy population. Ni-Mo (NM), Y-modified (NMY), and Y$ _2$ O$ _3$ -containing (NMYO) alloys were tested in molten fluoride salt at 750°C. Corrosion penetration decreases systematically from NM to NMY to NMYO, consistent with the predicted reduction in vacancy-mediated transport. The same trend is observed in mass change, with net weight loss decreasing from 0.52% for NM to 0.23% for NMY and 0.09% for NMYO. These results are consistent with an alloy-side transport contribution from defect trapping and reduced atomic transport. This study therefore suggests point defect engineering as a promising alloy design strategy for extreme nuclear environments.
Materials Science (cond-mat.mtrl-sci)
33 pages, 8 figures, 6 tables
Contact-mediated asymmetric delay and rate memory in snapping beam pairs
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Gavin Linton, Shima Mahmoudirad, Nidhi Pashine, Anupam Pandey
Slender structures in dense environments interact through contact, which alters how and when they become unstable. Here we show that contact makes snap-through history dependent, so that when and whether a beam pair snaps depends on how long the contact is loaded. Under cyclic compression, the pair snaps on loading, snaps on unloading, or stays packed, with the loading and unloading rates selecting among the three. Upon contact, one beam rolls along the other without slip, and faster driving lets it roll further before it slides and snaps: to larger compression on loading and to smaller compression on unloading. This delay is asymmetric between loading and unloading as the unloading branch carries a memory of the loading rate. Interestingly, above a threshold compression the pair snaps even when the compression is stopped, with the time to snap diverging at that threshold. By exploiting this asymmetric, rate-dependent delay, we program ordered sequences of snap events in arrays of pairs with tunable gaps, and demonstrate that the energy dissipated per cycle becomes a two-parameter function of the loading and unloading rates, increasing fourfold when, at the fastest loading, the return is slowed.
Soft Condensed Matter (cond-mat.soft)
8 pages, 4 figures
Spectral Mapping Theorem between SU(N) and SU(Ns/N) Heisenberg Models and Exact Diagonalization of SU(4) and SU(7) Long-Range Ordered Phases on the Triangular Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
We first show that, for the SU(N) Heisenberg model with isotropic two-site interactions on an arbitrary lattice of Ns sites, the full spectrum in its singlet sector (when N divides Ns) is the negative of the full spectrum in its singlet sector of the SU(Ns/N) Heisenberg model defined on the same lattice. This theorem, valid for models with the fundamental irreducible representation (irrep) at each lattice site, follows naturally from a transposition operation in the basis of Standard Young Tableaux (SYTs). Second, this basis – previously recognized as particularly convenient for exact diagonalization (ED) of SU(N) Heisenberg models – admits an efficient, memory-saving implementation, thereby enabling large-scale diagonalizations for unprecedented system sizes Ns and numbers of colors N>3. We apply these ideas to an ED study of the SU(4) and SU(7) Heisenberg models on the triangular lattice (TL), extending the calculations up to Ns=28 sites. In particular, starting from the SU(4) case, whose nearest-neighbor ground state remains debated, we confirm that next-nearest-neighbor couplings stabilize four-sublattice long-range order. We further find that increasing the number of colors from N=4 to N=7 provides another route toward a Néel-like ground state, even without such additional couplings. N = 4 to N = 7 provides another route toward a Néel-like ground state, even without such additional couplings.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 12 figures,
Interfacial Coupling Reshapes Nonlinear Polarization in a Spin-Defect van der Waals Heterostructure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Lena Dalifoski, Eveline Mayner, Poonam Singh
Van der Waals heterostructures offer a direct route to couple an optically active layer to a two-dimensional spin sensor, yet their coherent nonlinear response at interfaces remains poorly resolved. Here, we use polarization-resolved second harmonic-generation imaging to resolve four distinct regions of a hexagonal boron nitride (hBN) -based heterostructure, native hBN, neutron-irradiated hBN containing negatively charged boron vacancies (VB-), PbI2 and their complete overlap. The detected intensity scales quadratically with incident power, consistent with a dominant second-order optical process. Polarization scans show that adding PbI2 transforms the distorted VB- SHG anisotropy into a predominantly fourfold response with a sixfold stronger SHG than native hBN alone. This non-additive nonlinear response occurs in the same layer architecture also shown to enhance defect photoluminescence, linking spin-defect sensitization to an interface-modified effective second-order susceptibility.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
15 pages, 4 figures
Reparameterizing GFN1-xTB for Ionic Liquids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
F. Stavarache, S. Calero, J. M. Vicent-Luna
Ionic liquids are materials whose properties can be tailored for a wide range of applications, but their chemical diversity and complex electronic structure make systematic screening using quantum-mechanical methods computationally demanding. Semiempirical quantum methods offer an alternative, although their accuracy depends on their parameterization. We investigate the reparameterization of the DFTB method GFN1-xTB for predicting structural, energetic, and electronic properties of ionic liquids. For this purpose, we built a database containing over 14,000 conformations to construct training datasets and explored different parameterization strategies fitted to binding energies, forces, HOMO-LUMO gaps, and geometries. Analysis of the original GFN1-xTB model reveals systematic errors in these properties, with distinct behavior for saturated and aromatic cations. Thus, we investigate two models: CXMIM-xTB, a targeted model trained on imidazolium-based ionic liquids, and IL-xTB, a more general model designed to describe systems containing saturated and aromatic cations. CXMIM-xTB improves the description of binding energies, geometries, and frontier orbital energies while retaining computational efficiency. The model is subsequently applied to estimate electrochemical windows of ionic liquids, providing values consistent with DFT and experimental values. IL-xTB follows a hierarchical parameterization strategy including different cation and anion families and substantially reduces the systematic errors of GFN1-xTB across the chemical space considered, providing a route for developing xTB parameterizations with broader applicability to ionic liquids. Overall, both parameterization strategies outperform the original GFN1-xTB model, demonstrating that reparameterized methods provide an efficient approach for connecting configurational sampling with quantum-mechanical properties of ionic liquids.
Soft Condensed Matter (cond-mat.soft)
Paper + SI: 27 pages, 17 figures
Nucleation at the GST–oxide interface and beam-driven ordering in amorphous Ge–Sb–Te: HAADF, EDS and electron pair distribution functions across a 4D-STEM dose series
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Mridul Kumar, Kirill Sobolev, Alexander Upcher, Yevgeny Rakita
Where crystal nuclei form in amorphous phase-change materials decides how they switch. We study six successive 4D-STEM scans, with simultaneous HAADF and EDS data, of a magnetron-sputtered Ge-Sb-Te (GST) film, restricted to the GST layer and its interface with the oxide beneath it. Nucleation sites do not differ in composition or number density: the nuclei lie on the same robust HAADF-EDS relation as the matrix, and at fixed HAADF the spread of the summed EDS signal equals its Poisson counting noise (ratio 1.03 +- 0.05). The nuclei are nevertheless crystalline and stand out in the 4D-STEM max-intensity virtual image (median z = 11.0) but not in HAADF (z = 1.3) or EDS (z = 0.3). We classify the film in four ways (HAADF intensity, I(q) phase mapping, PCA of the whole diffraction patterns and a self-supervised SimCLR encoder) and compare the electron pair distribution functions (PDFs) of all classes after calibrating reciprocal space on the Au cap. All bulk classes share one short-range structure (first shell 2.70-2.74 Å); towards the interface the first sharp diffraction peak (FSDP) moves to lower q, and every method isolates a thin interface-edge environment with a shorter or missing first shell. The I(q) classification isolates, in every scan, an interface environment that holds 62-100% of the nucleus pixels (1.2-2.5-fold above depth) and persists when the nucleus pixels are removed before classification. The interface, rather than a distinct composition or density of the nucleating volume, therefore marks where nuclei form. Over 4.7e3 e/Å^2 the HAADF signal falls by 17%, the first shell shortens by 0.03 Å and the FSDP narrows by 9%, apparently ordering the film as it damages it. All analyses used PySTEMLab, an interactive 4D-STEM analysis environment developed for this work.
Materials Science (cond-mat.mtrl-sci)
Superlattice-Stabilized Fractional Chern Insulators in a “Berry Basin” Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Yongxin Zeng, Andrew J. Millis
The discovery of integer and fractional Chern insulators in rhombohedral graphene, following their discovery in the isolated topological flat band in twisted MoTe$ _2$ , motivates a search for the conditions under which an electronic band can host a topological correlated state. In this Letter we introduce a Berry basin" model which captures the essential features of rhombohedral graphene: a dispersive band with a flat bottom, momentum-space winding of a layer” degree of freedom, and Coulomb interactions, while also including periodic potentials, enabling controlled studies of the interplay of quantum geometry, superlattice modulation, and electron-electron interactions in producing correlated topological states beyond the isolated topological band paradigm. While integer Chern insulators emerge at strong coupling without a superlattice potential, stabilizing the fractional state requires nonzero potential for all interaction strengths we access. We provide insight into the greater robustness of integer and fractional Chern insulators in rhombohedral graphene when electrons are polarized away from the moiré interface. Our results establish a new class of systems that host robust fractional Chern insulators and provide a controlled numerical platform to test competing theories of interacting topological phases.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Local Suppression of Superconductivity in Niobium Films by Focused Silicon Ion Implantation
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Rochelle Y. Qu, Shunsuke Nishimura, Max Proepper, Joseph J. Barrera, Alexander Brooks, Joshua Vande Berg, Achim Nadzeyka, Aravind R. Sreeja, Jay C. LeFebvre, Roger K. Lake, Shane A. Cybart
Magnetic flux trapped in a superconducting circuit shifts the critical currents of nearby Josephson junctions and disturbs the operation of the circuit. The usual remedy is a moat etched through the ground plane to hold the flux away from the logic. We report direct write silicon ion implantation with a focused ion beam as a way to make moats without etching the film, by locally suppressing superconductivity in niobium (Nb). Single implanted lines were written across Nb electrodes in films of three thicknesses over two orders of magnitude in ion fluence, and the transition temperature, resistance, and critical current density of each line were measured. The transition temperature of the line falls with fluence while the surrounding Nb is unchanged, and the critical current density falls by about two orders of magnitude before the line becomes resistive at 4.2 K. The product of the critical current and the resistance of the lines follows a single power law in reduced temperature. This gives an estimate of the critical current of a line at any temperature from its transition temperature and resistance. A time dependent Ginzburg-Landau simulation indicates that an implanted region can capture and hold a vortex. From these results we suggest a starting ion energy and fluence for implanted moats in a 100 nm Nb ground plane at 4.2 K and estimate the equivalent broad beam fluence.
Superconductivity (cond-mat.supr-con)
Transition-Metal Chalcogenide Nanowires: A First-Principles Study of Stability, Electronic Structure, and Mechanical Response
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Danilo de Araújo Moura, Flavio Bento de Oliveira, Andreia Luisa da Rosa
Subnanometer transition-metal chalcogenide nanowires provide a one-dimensional platform in which electronic functionality and mechanical response can be tuned through chemical composition. Here, density functional theory calculations are combined with machine-learning force-field (MLFF) molecular dynamics to investigate MoS, MoSe, MoTe, WS, WSe, and WTe nanowires. The optimized structures are dynamically stable within the harmonic approximation, and their electronic character evolves systematically across the chalcogen series: MoS, MoSe, WS, and WSe are metallic, whereas MoTe and WTe are semiconducting, with HSE06 band gaps of 0.52 and 0.20 eV, respectively. The effective axial stiffness decreases from sulfides to selenides and tellurides, consistent with the increase in metal–chalcogen bond length; using a circular effective cross section, the corresponding Young moduli range from 392 to 718 GPa. All six nanowires have negative formation energies relative to the selected elemental reference phases. MLFF trajectories extending to 2.5 ns at 300 K preserve the one-dimensional morphology and local atomic order, providing evidence of finite-temperature dynamical stability on the simulated time scale. The corresponding MLFF molecular-dynamics energy traces are shown in. We further examine the response of the nanowires to axial strain and curvature, including strain-induced band-gap modulation in the tellurides. These results establish composition and mechanical deformation as complementary routes for tuning the electronic and mechanical properties of ultrathin transition-metal chalcogenide nanowires and support their further investigation as components of flexible nanoelectronic systems.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Dispersion of low-energy optical excitations in NiPS$_3$ explained by singlet polaron theory
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
I. J. Hamad, C. S. Helman, A. E. Feiguin, L. O. Manuel, A. A. Aligia
Optical and resonant inelastic X-ray scattering (RIXS) experiments in the van der Waals antiferromagnet NiPS$ _3$ have revealed narrow excitonic resonances near 1.5 eV whose microscopic origin remains under debate. In this work we study the momentum dependence of these excitations using the singlet-polaron theory (SPT) previously developed for NiPS$ _3$ . Within its framework, we calculate the spectral function of the corresponding effective model and extract the dispersion of the resulting quasiparticles. The theory naturally predicts two singlet excitations whose dynamics arise from their propagation in the zig-zag antiferromagnetic background ($ S=1$ ) coupled to two-magnon processes. We show that the dispersion of the lowest-energy quasiparticle agrees very well with the excitonic dispersion measured by RIXS, reproducing both its overall shape and bandwidth along high-symmetry directions of the Brillouin zone. Our results provide a consistent interpretation of the optical excitations in terms of dispersive singlet polarons, and suggest that similar mechanisms may govern excitonic dynamics in other layered van der Waals antiferromagnets.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 6 figures
Framework for an AI-Ready ARPES Community Database
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Zhi-Xun Shen, Jin Gene Wong, Karen Lei, Leon Garcia, Felix Baumberger, Sergey Borisenko, Aaron Bostwick, Ting Cao, Tanny Chavez, Yulin Chen, Monika Choudhary, Andrea Damascelli, Dan Dessau, Thomas P. Devereaux, Sandy A. Ekahana, Alexei Fedorov, Atsushi Fujimori, Yucheng Guo, M. Zahid Hasan, Makoto Hashimoto, Yu He, Philip Hofmann, Zahid Hussain, Harold Y. Hwang, Zhurun Ji, Chunjing Jia, Timur K. Kim, Phil D. C. King, Takeshi Kondo, Alessandra Lanzara, Chun Lin, Donghui Lu, Matteo Michiardi, Sung-Kwan Mo, Brian Moritz, Laurenz Rettig, Eli Rotenberg, Takafumi Sato, Kyle M. Shen, Jonathan A. Sobota, Inna Vishik, Shuolong Yang, Ming Yi, Timothy Zaklama
Condensed matter stands to gain profoundly from widespread adoption of artificial intelligence (AI). However, its current means of data organization impedes this endeavor. As a premier measure of electronic structure underlying material properties, Angle-Resolved Photoemission Spectroscopy (ARPES) has accumulated over four decades of spectra, yet the community’s publication-centered workflow preserves only a highly selected fraction of its experimental record. A shared data ecosystem could transform these fragmented measurements and their contexts into a persistent, collective scientific memory, creating immediate value for reproducibility and reuse while laying the foundation for AI-enabled discovery. In this Perspective, we report outcomes of a recent community workshop and propose a practical path toward such an ecosystem. Its benefits unfold along three timescales. In the near term, standardized, searchable, and citable datasets strengthen analysis pipelines independently of AI. In the intermediate future, community-validated tools operating across laboratories could enable broader reuse and increasingly closed-loop automated experiments. In the long term, a diverse corpus of measured electronic spectra could support foundation models for quantum matter. Looking forward, a diverse corpus of measured electronic spectra could support foundation models for quantum matter and new discoveries. We discuss lessons from existing scientific databases, the current state of AI in ARPES, as well as areas of community convergence on data organization, access, credit, governance, and a staged pilot program.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con), Artificial Intelligence (cs.AI)
Preprint under review
Valley-resolved high harmonics probe symmetry breaking beyond the Dirac cone
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Pablo Pais, Alfredo Iorio, Marcelo F. Ciappina
Low-energy electrons in graphene obey an emergent, rotationally invariant Dirac equation, while the honeycomb lattice enters only through higher-order, symmetry-breaking corrections, the leading one being trigonal warping. This provides a unique solid-state arena to address a cornerstone challenge in quantum gravity: how to detect ultraviolet symmetry-breaking granular corrections, suppressed by a fundamental scale, atop an emergent infrared relativistic continuum. We show that intense counter-rotating $ \omega$ -$ 2\omega$ fields and valley-resolved high-harmonic generation (HHG) provide such a probe. Within a family of models that interpolates continuously between the isotropic Dirac cone and nearest-neighbour graphene at fixed Fermi velocity, the valley contrast of the harmonic yield vanishes identically in the symmetric theory, grows linearly with the warping coupling, and its valley-even counterpart appears only at second order, as expected from effective-field-theory power counting. The stronger the laser, the farther it drives electrons from the Dirac points, so the laser intensity plays the role of the collision energy. For the fourth harmonic, the leading warping correction alone accounts for the valley contrast of real graphene up to fundamental intensities of about $ 10^{11}$ W/cm$ ^2$ , below the damage threshold of monolayer graphene, whereas the fifth harmonic already reveals higher-order lattice corrections at intensities around $ 10^{10}$ W/cm$ ^2$ . The two harmonics, which rotate in opposite directions, are emitted by opposite valleys. Valley-resolved harmonics are far more sensitive than the residual valley populations, making them a practical detector of lattice-scale physics hidden beneath an emergent Dirac theory.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th), Atomic Physics (physics.atom-ph)
6 pages, 4 figures
Three-dimensional reconstruction of weakly scattering objects from single-defocus 4D-STEM data
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Kousuke Ooe, Yufan Shen, Yuichi Shimakawa, Daisuke Kan, Scott D. Findlay
Three-dimensional (3D) atomic-structure analysis is of central importance in (scanning) transmission electron microscopy (STEM). STEM techniques to reconstruct 3D structure include tilt-series or defocus-series annular dark-field, best suited to heavier atomic species, and dynamical-scattering-model inversion applied to single-defocus four-dimensional (4D) STEM data, requiring computationally expensive post-experiment analysis. In this study, we propose a 3D-structure linear inversion (3D LINV) STEM algorithm, which enables a fast and direct reconstruction of 3D structures from a single-defocus 4D-STEM dataset. This method is based on solving linear equations relating the measured 4D-STEM data and the unknown 3D specimen potential under the thick weak phase object approximation. We show the capabilities of 3D LINV STEM through systematic 4D-STEM simulations across various observation parameters such as specimen thickness, partial coherence, and shot noise, and through an experimental demonstration of 3D structure reconstruction of a stacked freestanding membrane with atomic-scale lateral resolution and nanometre-scale depth resolution.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
13 pages, 7 figures
Weyl’s theorem and the theoretical origin of Boson peak in two-dimensional scalar spring network
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-14 20:00 EDT
The origin of the anomalous low-frequency vibrational density of states (VDOS) universally observed in amorphous solids has been debated for decades. In this work, we model amorphous solids as a zero-temperature scalar spring network, the simplest model that captures both the amorphous structure and the features of the anomalous VDOS. Using this scalar network, we mathematically demonstrate that disorder can lead to a shift of the VDOS toward low frequencies, thereby accumulating the anomalous part there. Disorder is defined through the topological connectivity of the network. The validity and universality of the theoretical framework are general and valuable for real-world scenarios because it rests only on Weyl’s theorem for Hermitian matrices and is free of perturbation and phenomenological assumptions. This work strips away complex factors and reveals, at the level of mathematical principles, a profound and clean mechanism for the origin of the anomalous VDOS in amorphous solids.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
13pages, 1figure
Programmable memristive circuits for reconfigurable collective pseudomagnetic ordering, transport, and learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Sichang Qiu, Yuxin Jiang, Yongchao Wu, Peng Han, Xinxin Gao, Zekun Huang, Ce Shang, Ronny Thomale, Tie Jun Cui, Shuo Liu
Programmable hardware typically uses fixed architectures, whereas complex physical systems obtain diverse behavior by connecting reusable local elements through different interaction rules. Memristive devices combine writable states with nonlinear dynamics, but translating these local properties into reconfigurable collective order and symmetry-governed transport remains challenging. Here we develop modular circuits configured through programmable connections between identical memristive units. Experiments establish binary conductance states as Ising-type pseudospins and show that signed feedback between units selects uniform or staggered pseudospin order. Circuit-model simulations then examine controllable domain-wall motion and pattern recovery. A symmetry encoder combines measured conductance patterns with sublattice labels and a selected symmetry rule to configure a fixed transport layer, implementing circuit analogs of ferromagnetic, antiferromagnetic, and altermagnetic transport symmetries. Although the antiferromagnetic and altermagnetic encodings share a compensated pattern, their distinct voltage spreading illustrates how programmed circuit symmetry affects transport. Device-calibrated simulations show that memristive dynamics generates history-dependent features for reservoir computing. By separating local memory from programmable interactions, symmetry encoding and task-specific readout, this architecture provides a modular route from device dynamics to collective order, symmetry-dependent transport, and learning.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
35 pages, 6 figures
Microscopic foundation for orbitronics: orbital exchange interactions, orbital-dependent transport, and orbital switching
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Recent experiments highlighted the essential role of the orbital degrees of freedom underlying current-induced magnetic dynamics. However, a microscopic picture of how orbital angular momenta are transferred between itinerant and localized electrons, and the way it feeds back into transport, remains elusive. Here we develop a theoretical framework for the orbital exchange interactions by generalizing the Anderson-Kondo model to incorporate the orbitals of conduction bands. Illustrating with the $ p$ -orbitals, we determine the way electrons acquire orbital polarization and its influence on the transport properties, uncovering the orbital counterparts of phenomena analogous to spin filtering and tunnel magnetoresistance. Reciprocally, we demonstrate that orbital-polarized currents can exert torques on localized magnetic moments without having to convert into spin currents, which enables electrical switching of magnetization even when spin polarization becomes inactive. These striking discoveries lay a microscopic foundation for orbitronics and reveal critical mechanisms for orbital manipulations of magnetic order.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
Matrix-product-state GPLHR for non-Hermitian many-body eigenproblems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Xingyao Wu, Zhangyu Yang, Yanbin Chen, Yu Wang, Feng Chen
Computing multiple eigenstates of non-Hermitian many-body operators plays an important role in investigating excitation spectra, spectral properties, and relaxation dynamics in interacting and open quantum systems. However, this task is challenging because the eigenvectors are generally nonorthogonal and the Hilbert space dimension grows exponentially with system size. Here, we formulate the generalized preconditioned locally harmonic residual (GPLHR) method in a matrix product state (MPS) framework to efficiently compute multiple targeted right eigenstates whose eigenvalues lie near a specified shift in the complex plane. Successive randomized compression (SRC) is employed to accelerate operator applications. We test the method on transcorrelated and complex Hubbard chains, an interacting non-Hermitian Su-Schrieffer-Heeger (SSH) chain, and a Liouvillian model. The results demonstrate that GPLHR combined with MPS provides an efficient and accurate approach for computing multiple eigenstates of non-Hermitian many-body operators.
Strongly Correlated Electrons (cond-mat.str-el)
Extended-range percolation on lattices with cubic and non-compact neighborhoods in three dimensions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Zhe Zhang, Yuxuan Fan, Yang Yang, Yusong Tu, Zhipeng Xun
Using MC simulations based on an efficient single-cluster growth algorithm, we investigate two types of three-dimensional extended-range percolation models, namely cubic and complex (non-compact) neighborhoods. We obtain high-precision percolation thresholds $ p_c$ for approximately 100 distinct structures and further explore the relationship between these thresholds and the topology of the lattices, which includes the total coordination number $ z$ , the number of sites $ z_i$ and these sites’ distance to the central site $ r_i$ of the given neighborhood in the $ i$ th coordination zone. Both bond and site percolation are analyzed for cubic neighborhoods on the SC lattice. For bond percolation, the asymptotic value of $ zp_c$ tends to Bethe-lattice behavior ($ zp_c\sim1$ ), and finite-$ z$ correction is found to be consistent with $ zp_{c}-1\sim a_{1}z^{-x}$ , where $ x=(d-1)/d$ . For site percolation, the value of $ zp_c$ varies non-monotonically, exhibiting an initial increase followed by a decrease with the coordination number $ z$ . Linear fitting leads to $ zp_c\sim2.5987(1)$ for large $ z$ , predicting a value of continuum percolation threshold of aligned cubes $ \eta_c=0.324838(12)$ using $ zp_c=2^{d}\eta_c$ . We then examine site percolation for non-compact neighborhoods extending to the fifth coordination zone on SC, FCC, and BCC lattices. Through a comparison of the three indices of $ z$ , $ \xi=\sum_iz_ir_i^2/i$ , and $ \zeta=\sum_iz_ir_i$ , we find that $ \zeta$ is effective in removing the degeneracy. The results obtained show power-law dependence $ p_c\propto(\zeta/K)^{-\gamma}$ with $ \gamma_{\mathrm{SC}}^{\zeta}=0.703(12)$ , $ \gamma_{\mathrm{FCC}}^{\zeta}=0.728(10)$ , and $ \gamma_{\mathrm{BCC}}^{\zeta}=0.699(12)$ for SC, FCC, and BCC lattices, and $ p_c\propto\zeta^{-\gamma}$ with $ \gamma^{\zeta}=0.719(9)$ independent of the underlying lattice. The number $ K$ indicates lattice connectivity.
Statistical Mechanics (cond-mat.stat-mech)
Non-Hermitian Two-Kink Control of Corner States in Twisted Chern Bilayers
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-14 20:00 EDT
Corner states are bound by boundary-mass defects, but this geometric anchoring restricts their spatial and internal control. Focusing on twisted bilayers assembled from Chern insulators with opposite Chern numbers, we show that a mass-phase kink carried by a non-Hermitian interlayer mass and an independent imaginary-momentum kink separate the spectral, in-plane, and interlayer control of mass-defect corner states. The mass-phase kink creates the parent corner pole and fixes its energy and intrinsic decay, while directed interlayer tunneling encodes its layer polarization. The imaginary-momentum texture instead reshapes the closed-boundary envelope and redistributes stationary right-state weight between corners. A twisted Qi–Wu–Zhang bilayer verifies this division on arbitrary, including concave, boundaries. A $ 30^\circ$ twisted Haldane dodecagon realizes twelve finite-energy parent states whose in-gap spectral manifold persists while boundary patterns redistribute its normalized right-subspace weight toward six, three, two, or one target corners. The two kinks therefore cooperate or compete while keeping spectral ancestry, spatial weight, and layer character distinct, thereby establishing a unified framework for controlling mass-defect corner states across disparate boundary geometries and mass textures.
Other Condensed Matter (cond-mat.other)
6 pages, 3 figures,
A Solvable Model in the Half-filled Landau Level
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
A solvable microscopic model of interacting electrons in a half-filled Landau level is presented. The Hamiltonian is a well-defined limit of the electron-electron interaction. The low energy sector consists of a set of independent, spatially interlaced, one-dimensional systems of non-interacting fermionic dipoles, each system with a Fermi sea ground state. The total number of dipoles in the set of Fermi seas forming the two-dimensional ground state equals the number of electrons in the system and the density of states at the Fermi level is that of a two-dimensional Fermi gas. The model is obtained by generalizing, or rather adopting, the existing exact solution on a thin, but not too thin, torus to the two-dimensional bulk case.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 3 figures
Generalized Constraint-Controlled Rheological Model: Two Constitutive Pathways under Sinusoidal Periodic Shear Deformation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Dario Nichetti, Alessio Zaccone
We formulate the Generalized Constraint-Controlled Rheological Model (GCCRM) for entangled linear and long-arm-branched polymer melts under sinusoidal periodic shear deformation (SPSD), spanning the linear and strongly nonlinear regimes. Molecular architecture, conformation, chain stretch, flow-active constraints, convective constraint release, dynamic tube dilation, and activated arm retraction define a common upstream molecular state. This state feeds two time-domain constitutive pathways (a configurational stress and a dissipative internal-variable stress) which are recombined before Fourier analysis. For branched polymers, the architecture is described by an entire backbone of molecular weight $ M_{bb}$ and $ N_a$ long arms of molecular weight $ M_a$ , with a compliance-weighted representative-constitutive-cell partition. The linear limit is normalized so that the configurational moduli sum to the entanglement modulus, while dynamic tube dilation and stretch drive distinct contributions to dissipative activation. Under reduced closures, GCCRM generates a smooth nonlinear elastic response with an onset of nonlinearity, an approximately logarithmic growth regime, an architecture-dependent maximum, and distinct high-deformation asymptotes. Fourier harmonics, ELR, VLR, and Lissajous curves are treated as post-processing observables of the total stress. The framework establishes a consistent constitutive architecture whose quantitative validation requires one parameter set per material across SPSD and, prospectively, transient shear histories.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Fluid Dynamics (physics.flu-dyn)
Ergodicity breaking transition beyond qubits
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Tanay Pathak, Abhik Kumar Saha
The local Hilbert space dimension is a fundamental parameter in quantum many-body systems, but its role in controlling the ergodicity-breaking transition remains less explored. We systematically study this question by introducing toy models of qudits in zero dimensions that exhibit an ergodicity-breaking transition. Using the hybridization condition, we analytically obtain the dependence of the critical value of the interactions on the local Hilbert space dimension. Numerical studies of spectral correlation measures show agreement with the theoretical predictions, hence confirming the existence of the ergodicity-breaking transition in these models. We further introduce a distinct higher spin version of the model and numerically obtain the same critical behavior, demonstrating that the observed critical point is independent of the microscopic structure of interactions considered.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
7+10 pages, 5+8 figures
Unlocking the potential of polymer networks for high strength through topology
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Zheqi Chen, Yu Zhou, Chenghai Li, Ho Cheung Shum, Zhigang Suo
A covalent polymer network is orders of magnitude weaker than individual covalent bonds. This large gap reveals an unrealized potential. The weakness of a network comes not from individual covalent bonds, but from how they are connected. Here we unlock this potential by identifying a topological criterion, involving optimally sparse crosslinks, long chains, and dense entanglements. Optimizing each topological variable alone is insufficient for high strength, yet exceptional strength emerges when they are combined within a narrow regime. We describe the physics of this synergy, and use the criterion to strengthen networks widely used but known to be weak. For example, we prepare a polyacrylamide hydrogel of 90 wt% water, amplifying strength from a commonly reported value of ~0.1 MPa to ~6.5 MPa. The exceptional strength is achieved without sacrificing other properties, such as softness, toughness, and elasticity. The criterion establishes topology as a general design principle for strong polymer networks.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Dynamical chiral symmetry breaking in rotating QED$_3$: critical flavor number and the occupation-reweighting channel
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
We study dynamical chiral symmetry breaking in $ (2{+}1)$ -dimensional QED on a rigidly rotating disc, $ \Omega R<1$ , within the rainbow Schwinger–Dyson framework. At zero temperature the rotation response of the condensate vanishes identically, so $ N_c^{\rm SD}(\Omega,T{=}0)=N_c^{\rm SD}(0)=2.60\pm0.01$ (using three operational definitions). At finite temperature, rotation suppresses the condensate through a dominant occupation-reweighting channel, $ \hat{\kappa}{\rm occ}=-1.55$ , accounting for $ \ge 99.995%$ of the linearized total response at the reference parameters, with self-consistent feedback amplifying it by $ 26.5$ . The screening channel is reported at fixed regularization, $ \hat{\kappa}{\rm scr}(\varepsilon = 0.01)=-0.97$ ; its $ \varepsilon \to 0$ behavior is logarithmically divergent. The crossover flavor $ N^{\ast}(\Omega)$ falls monotonically at fixed temperature (a corollary). The critical flavor number is unchanged by rotation at $ T=0$ (theorem). Together these results set the finite-temperature reference for the model.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
28 pages, 4 figures
Realistic Simulation of Valence-band Photoemission Spectra by using First-principles Calculations on the Basis of FLAPW Method
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Noriaki Hamada, Satoshi Nakamura, Kenta Takahashi, Mario Okawa, Tomohiko Saitoh
In order to reproduce experimental photoemission spectroscopy (PES) data by using band structure calculations with linearized augmented-plane-wave method, we developed a new method to calculate the atomic-subshell photoelectron differential cross section (PE-DCS) of the valence band. PE-DCS was calculated to be the sum of the products of the partial density of states (PDOS) and the photoionization differential cross section (PI-DCS) of each atomic subshell. To construct an appropriate PDOS beyond the conventional muffin-tin sphere (MTS) PDOS, we proposed a ``nearly-neutral atomic sphere”, which can be defined as a natural extension of MTS. Although the calculational method for atomic-subshell PI-DCS was the standard Hartree-Fock-Slater method, we developed a new computer code in order to deal with the unoccupied electron shells in the ground state of isolated atoms up to $ \sim$ 10 keV. Details of the PE-DCS calculations were examined by using two simple examples of Na metal and NaCl, and then, the method was applied to hard x-ray PES (HX-PES) data of CuAlO$ _2$ . The experimental spectra were satisfactorily reproduced, demonstrating the potential applications of our method to HX-PES spectra of many compounds.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
11 pages, 8 figures
Journal of the Physical Society of Japan 93, 054709 (2024)
Single-Particle Spectroscopy and Cross-Barrier Dynamics in Inhomogeneous Luttinger Liquids via Unified Field Bosonization Technique
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Soundarya P, Venkata Suryanarayana M, Joy Prakash Das
The Unified Field Bosonization Technique (UFBT) is employed to investigate the single-particle properties of inhomogeneous Luttinger liquids containing localized clusters of impurities in the presence of forward-scattering interactions. Within this framework, fermionic two-point correlation functions are used to derive the leading-order singular contributions to the dynamical density of states (DDOS) and the cross-barrier tunneling conductance. The results reveal distinct power-law behaviours of the DDOS near the impurity cluster and in the far-field regime. The tunneling conductance exhibits a power-law temperature dependence, decreasing with decreasing temperature for repulsive interactions and increasing for attractive interactions, while remaining temperature-independent in the noninteracting limit. The impurity cluster modifies the amplitudes and spatial structure of these observables, whereas their characteristic power-law exponents are determined solely by the interaction parameters. The formulation accommodates arbitrary impurity strengths without requiring perturbative expansions in the impurity or interaction strengths. The characteristic scaling behaviour emerges directly from the fermionic correlation functions, without an explicit renormalization-group (RG) treatment of the impurity strength, while the weak-interaction limit recovers the leading perturbative correction to the tunneling response. These findings establish UFBT as a unified framework for describing local spectral properties and cross-barrier transport in inhomogeneous Luttinger liquids.
Strongly Correlated Electrons (cond-mat.str-el)
Enhancement of local magnetic ordering temperature due to non-magnetic disorder in anti-Heusler alloy Al$_2$MnCu
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Soumya Bhowmik, Suvayan Saha, Saikat Debnath, Arka Patra, Biswarup Satpati, Maxim Avdeev, Shishir Kumar Pandey, Chandan Mazumdar
Structural disorder is generally regarded as detrimental to magnetism. Since magnetic properties are governed by both the arrangement of magnetic atoms and the crystal environment, including non-magnetic atoms that mediate exchange interactions, the distinct role of magnetic and non-magnetic disorder remains less understood. The recently reported anti-Heusler alloy, Al$ 2$ MnCu, forming with $ \sim$ 50% intra-symmetry site disorder (B2) involving the magnetic Mn atom and $ \sim$ 5% inter-symmetry site disorder associated with non-magnetic Al and Cu atoms, offers a good platform to disentangle the individual roles of magnetic and non-magnetic atomic disorder. Our magnetic critical analysis, in the vicinity of the Curie temperature ($ T{\rm C}$ ), does not lead to any conventional single universality class expected for a standard ferromagnet; instead, the non-monotonic temperature dependence of effective critical exponents points towards more complex magnetic interactions, akin to inhomogeneous ferromagnets. Dc magnetometry complemented by higher-harmonic ac magnetic susceptibility data, further confirms the persistence of locally ordered magnetic clusters above $ T_{\rm C}$ . Theoretical analysis establishes that the enhancement of the local magnetic ordering temperature arises directly from the strengthening of exchange interactions due to the small degree of non-magnetic disorder, whereas $ T_{\rm C}$ is hardly influenced by the much larger level of magnetic-atom disorder. The combined experimental and theoretical investigations on the anti-Heusler alloy Al$ 2$ MnCu reveal and explain the unusual observation of nonmagnetic disorder-induced elevation of $ T{\rm C}$ , providing a paradigm for the counterintuitive role of disorder in magnetic materials.
Materials Science (cond-mat.mtrl-sci)
Hidden Spin-Valley Hall Effect and Gate-Switchable Electric Hall Effect in 2D Altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Jiajun Lu, Mu Tian, Chaoxi Cui, Zhi-Ming Yu, Yugui Yao, Run-Wu Zhang
Hidden beneath the vanishing charge Hall response of altermagnets are spin-up and spin-down Hall currents of opposite sign—concealed, not absent—whose cancellation is enforced by symmetry. When these spin states are locked to distinct valleys, the hidden currents constitute a spin-valley Hall effect. Here we show that in 2D altermagnets with spin-valley-layer coupling (SVLC), a gate field unveils this hidden spin-valley Hall response.~By lifting the symmetry-enforced compensation between valleys with opposite layer polarizations, the field converts the hidden response into a net charge Hall signal, yielding a gate-switchable electric Hall effect (EHE) enabled by SVLC. Using collinear spin layer group (cSLG) theory, we classify all 158 altermagnetic cSLGs, identify 32 that support SVLC, and predict monolayer Mg$ _2$ Os$ _2$ (SO$ _5$ )$ _2$ and the Ca(CoN)$ _2$ -family as candidate materials. First-principles calculations for Mg$ _2$ Os$ _2$ (SO$ _5$ )$ _2$ reveal reversible valley splitting, a gate-switchable Hall response, and a Kerr rotation exceeding 1 mrad whose sign reverses together with the EHE signal. These results establish a symmetry-based route to all-electrical valley-spin control and identify altermagnets as promising platforms for high-performance valley transport and electrically switchable magneto-optics.
Materials Science (cond-mat.mtrl-sci)
7 pages, 3 figures
Indirect prediction and screening of frustrated magnetic materials using machine learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Regina Burganova, Irina Piyanzina, Ruslan Akhmerov, Alexander Sigov, Maxim Fedorov
Magnetic frustration is commonly quantified by the frustration index, calculated from the Curie-Weiss and Neel temperatures. Because both quantities are not simultaneously available for most materials, direct prediction of the magnetic frustration index remains challenging. Here, we propose a machine learning workflow for indirect prediction of the frustration index and consequent screening of potential frustrated magnetic compounds through independent prediction of Curie-Weiss and Neel temperatures. In our work, composition-based models implemented via the CatBoost algorithm, trained on experimental data were optimized using chemically informed dataset subdivision. The highest predictive accuracy was achieved for the rare earth-oxide model in predicting Neel and for the rare earth model in predicting Curie-Weiss. Ensemble uncertainty was incorporated through a conservative frustration index to improve the reliability of candidate selection. Screening of approximately 67000 Materials Project compounds identified 20 high-confidence frustrated magnetic candidates, including several experimentally known frustrated magnets and previously unexplored oxide systems potential for further investigation.
Materials Science (cond-mat.mtrl-sci)
Field Response of the Orbital Moment Probed by Integrated Magnetic Circular Dichroism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Qian-Sheng Shi, Ziqiang Wang, Jian Kang, Yi Zhang
Magnetic circular dichroism (MCD) is an optical probe of orbital time reversal symmetry breaking. Although frequency integrated MCD is related to the self-rotation contribution to orbital magnetization at zero field, its magnetic response generally differs from the thermodynamic orbital susceptibility. Here, we define the MCD susceptibility and derive general expressions for multiband systems using an electromagnetic $ U(1)$ gauge invariant approach. For insulators, the response contains contributions from the non-Abelian quantum metric, Berry curvature, and field induced interband mixing. For metals, a finite temperature Green function formulation separates the smooth response into Fermi sea and Fermi surface contributions. An independent Landau level calculation confirms the expressions for the zero-field MCD moment and its linear magnetic response. In a continuum model for twisted bilayer graphene, the MCD susceptibility vanishes within the charge neutrality gap, while the thermodynamic orbital susceptibility remains markedly diamagnetic. Near the gap edges, the orbital moment term dominates the response. Features near the van Hove energies are associated with density of states enhancement. These results clarify how the two susceptibilities reflect different orbital processes even for the same electronic structure and thus establish the MCD susceptibility as a distinct probe of orbital magnetic response.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 2 figures in main text; 33 pages, 4 figures in SM
Developing the Statistical Mechanics of Evolving Assembly Spaces
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Anisha K. Yeddanapudi, Abhishek Sharma, Ian Seet, Leroy Cronin
A gap exists in connecting biological evolution within the framework of statistical mechanics. It has been hoped that statistical mechanics would provide us with a general predictive principle for the emergence of novelty and complexity. However, the emergence of novel functional features initiated by stochastic processes remains difficult to describe, because these processes commonly arise outside near-equilibrium or linear-response regimes. To understand how environmental influences generate diverse, open-ended, complex objects by driving physical systems to specific regions of phase space over long spatial and temporal scales, a new approach to non-equilibrium thermodynamics is necessary. Here, we present the coupling of assembly theory (AT) with statistical mechanics as a framework that works within the laws of thermodynamics, but can contextualise the processes of novelty, complexity, and evolution within these laws. We map construction processes from physical space to assembly space (AS) and introduce the concept of an assembler, a machine that constructs objects contingent on previous states and is represented by bitwise operations. Using this approach, we apply principles from stochastic thermodynamics with AT to define selection within large combinatorial spaces1 and estimate the work required to create novel and complex objects. This approach allows us to represent complex processes, such as selection, within large combinatorial spaces as a set of rules for a memory-feedback loop followed by the assembler. This framework concretely defines the relationships between thermodynamics and information theory by introducing a novel aspect of physics that uses history and causal contingency to influence the probabilistic time evolution of complex systems.
Statistical Mechanics (cond-mat.stat-mech)
26 pges, 5 figures, 50 references
Reversible intrinsic-extrinsic crossover of the anomalous Hall effect in PrAlSi via Al/Si ratio tuning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Huiyang Yang, Xiaohua Luo, Hongwei You, Wei Ren, Yuntao Gao, Changcai Chen, Zhishuo Zhang, Chunsheng Fang, Shengcan Ma
The anomalous Hall effect (AHE) in magnetic Weyl semimetals arises from distinct microscopic origins-intrinsic Berry curvature and extrinsic scattering mechanisms-yet reversible switching between these regimes within a single material platform remains elusive. Here, we demonstrate that off-stoichiometric tuning of the Al/Si ratio (from ~1.05 to ~0.75) reversibly drives an intrinsic-extrinsic-intrinsic crossover of the AHE in PrAlSi single crystals. Across four compositions spanning a narrow Si variation (PrAl0.93Si0.89 to PrAl0.79Si1.06), the anomalous Hall conductivity (AHC) exhibits a non monotonic arch (170-1413- 507-164 {\Omega}-1cm-1). The intermediate composition PrAl0.90Si0.94 (Al/Si ~0.96) exhibits high carrier mobility, multi carrier transport, yielding a giant AHC of 1413 {\Omega}-1cm-1 dominated by extrinsic skew-scattering. The Si-poor and Si-rich compositions exhibit lower AHC values and intrinsic Berry-curvature-dominated AHE, establishing a composition-driven intrinsic-extrinsic-intrinsic crossover. Deviating from the intermediate composition suppresses mobility and reverses carrier type from hole-like to electron-like. The Al/Si ratio thus serves as a chemical knob that primarily modulates the Fermi level via compositional band filling, while off-stoichiometry-induced chemical disorder plays a subordinate role in determining the AHE mechanism. These results position off-stoichiometric PrAlSi as a tunable platform where subtle compositional variation reversibly switches the AHE mechanism.
Materials Science (cond-mat.mtrl-sci)
31 pages, 5 figures
Coexistence of Multiple Distinct Corner-State Classes via Nearest-Neighbor Couplings Alone
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-14 20:00 EDT
Luhong Su, Dongyi Wang, Shenglong Guo, Xinjiang Chen, Lei Zhou, Shaojie Ma, Mengyao Li
The coexistence of multiple classes of localized states, including different types of topological corner states, is highly desired; yet its realization typically requires sufficiently strong long-range couplings, bringing challenges to experimental realizations across a wide range of systems. Here, we demonstrate the emergence of multiple localized corner modes evolution under purely nearest-neighbor coupling conditions without long-range couplings, not even next-nearest-neighbour couplings, and experimentally confirm their coexistence in a single lattice. Our platform simultaneously hosts type-I and type-II corner states, corner localized bound states in the continuum, flat-band states, and edge states. We experimentally realize such lattice using topolectrical circuits, a system that can strictly exclude long-range coupling by design, enabling direct characterizations of both the energy-band spectrum and the spatial profiles of the localized eigenmode. This work demonstrates that solely modifying nearest-neighbor couplings can replace the role of long-range interactions in realizing multiple types of corner states, providing a deterministic and widely accessible route to multiple corner-state classes and rich localized states, with immediate potential for mode-division multiplexing and multimode topological devices.
Other Condensed Matter (cond-mat.other)
Spatial interference changes the symmetry class of a Josephson element
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Spatial interference can break the inversion symmetry of an effective Josephson potential even in a laterally homogeneous junction with inversion-symmetric local energy. We derive a general criterion based on harmonic-dependent complex spatial form factors: a single local harmonic remains a shifted cosine, whereas multiple harmonics can acquire phases incompatible with any common inversion center, permitting cubic interactions and three-wave mixing. Phase reflection reverses all odd-order expansion coefficients about corresponding minima while preserving the even-order ones. For a capacitively shunted junction at fixed charging energy and arbitrary offset charge, it also preserves the complete quantum spectrum, enabling reversal of the odd nonlinear sector without spectral retuning. A centered cross junction with multiple local harmonics is one concrete example. Within the imposed-field model, a three-component magnetic field can generate an inversion-asymmetric effective potential, and reversing an odd number of field components exactly reflects it without changing the quantum spectrum of the capacitively shunted junction.
Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
7 pages, 1 figure
Variational Minimization of Almost Strong Zero Modes in Parafermionic Wires
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Niklas Tausendpfund, Matteo Rizzi
Strongly interacting fermionic chains obeying a $ Z_n$ symmetry can host topological phases with highly degenerate ground-state manifolds. The different ground states are connected by strongly bound fractionalized edge modes called parafermionic zero modes. While exactly preserved under time evolution at zero temperature, interactions lead to a destabilization of these modes at finite energy densities, and, given a generic Hamiltonian, obtaining the lifetime of these modes is often impossible as it requires knowledge of the full spectrum of the Hamiltonian or long time evolutions. Here, we propose a novel quantum-inspired algorithm that can be used to variationally search for these almost strong zero modes in generic parafermionic chain models. We demonstrate analytically and numerically that our ansatz faithfully reproduces the exact results and finds strongly bound parafermionic operators in the non-integrable Kitaev-Hubbard chain and chiral Potts model. Our results further allow us to verify the existence of a true strong zero mode in the symmetrical limit of the chiral Potts model for $ Z_3$ -parafermions.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
14 pages, 8 Figures
Approaching Irrational Quantization
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Zhihong Wu, Zhimou Chen, Siyuan Zhang, Jinyang Chen, L. N. Pfeiffer, K. W. West, Yang Liu, Xi Lin
The integer and fractional quantum Hall effects reveal that quantized physical responses can take integer and fractional values, respectively. This naturally raises the question of whether quantization can extend beyond rational numbers to an irrational value. Here we show that such a quantized response can emerge from the limiting behavior of a finite, experimentally realizable geometric network. We develop a method based on infinite geometric structures, in which a sequence of finite networks rapidly converges toward an infinite limit. Following this approach, we identify a planar network whose normalized resistance converges to the irrational value $ \sqrt{3}$ , and realize a finite approximation with high-precision geometric control. The measured normalized resistance is $ 1.735 \pm 0.001, h/e^2$ for a fully occupied Landau level in the designed pattern. Our experimental results extend the concept of quantization beyond rational values and demonstrate that an irrational quantized response can be approached through a finite physical system.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 4 figures in manuscript; 5 pages, 1 figure and 1 table in supplemental material
Magpie: A Graphical Magnon Software
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Magpie is a fully graphical linear spin-wave software which has its main focus on 3-d visualisation of magnetic models and magnon dispersion relations. The software is distributed under an open-source license and is written in high-performance, portable C++. Its modular architecture allows for a rapid development of new calculation modules and permits the inclusion into external applications. Included code generators ensure seamless interoperability with other linear spin-wave libraries.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
11 pages, 4 figures
Ionomer-free Iridium Anodes with Low Loading for Zero-gap Electrolyzers via Direct Atomic Layer Deposition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Peter M. Piechulla, Iris Blommestein, Anne van Gerven, Henri Pelzer, Ezgi Demiröz, Jonas Englhard, Mingliang Chen, Julien Bachmann, J. Ruud van Ommen
Proton exchange membrane water electrolysis (PEMWE) is among the most promising techniques to provide hydrogen as both energy carrier and feedstock for the chemical industry, due to its compatibility with intermittent renewable electricity sources. However, a major bottleneck in scaling up PEMWE is the limited supply of the anode catalyst Ir. This work shows a novel approach to tailoring ionomer-free catalyst layers based on custom-made microporous substrates and two different atomic layer deposition (ALD) processes, both using Ir(EtCp)(CHD) precursor. Thermal ALD using O3 as counter-reactant yields mostly metallic Ir/IrOx and an electrode Ir loading of 0.21 mg/cm2. The PEMWE cell-level performance is comparable to a commercial catalyst-coated membrane anode despite 7x lower loading, and is maintained over an accelerated durability test equivalent to 600 h of intermittent operation. Moreover, using a low-loading ALD-made cathode, the total platinum group metal loading is only 0.24 mg/cm2. Plasma-enhanced ALD reduces the Ir loading to 0.04 mg/cm2 by tailoring the catalyst distribution, however, yields lower-activity IrO2. Finally, direct ALD catalyst deposition needs no ionomer-bearing ink. The anodes are therefore compatible with various membrane materials, as demonstrated in a CO2 electrolysis experiment with an anion exchange membrane.
Materials Science (cond-mat.mtrl-sci)
36 pages, 12 figures
Latent Heat and Raman Spectrum Change on Phase Transition of Water Including Calcium Chloride
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
This study investigates how Raman O-H stretching signatures may be able to track latent-heat-related energetics during water’s phase transitions. Prior work on latent heat and Raman analysis of phase change is reviewed to establish theoretical approach. Building on a framework that links O-H frequency shifts to hydrogen-bond strength, we relate entropy/enthalpy variations to temperature-dependent changes in peak position and integrated intensity. Experiments on pure water and impurity-doped samples, specifically CaCl$ _2$ , were performed under controlled temperatures, and spectra were deconvoluted and integrated over defined bands. The Raman metrics exhibit reproducible temperature dependence that captures the transition window, while CaCl$ _2$ induces systematic shifts and measurable modifications in the apparent latent-heat signature. These results highlight Raman spectroscopy as a quantitative probe of thermodynamic evolution and impurity effects in water and related systems.
Materials Science (cond-mat.mtrl-sci)
9 pages, 9 figures
Emergence of Active Foams in a Minimal Cognitive Flocking Model
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Aryan Dwivedi, Diganta Bhaskar, Anil Kumar Dasanna
We investigate a minimal visual perception-driven model of self-propelled particles that interact through purely position-based cohesive steering within a finite vision cone, in the absence of velocity alignment and physical volume exclusion. Building on a previously proposed minimal cognitive model, we extend the interaction range from the previously studied short-range and distance-independent limits to an intermediate regime, enabling a systematic investigation of how a finite vision range influences collective behavior. We find that this regime exhibits a rich state diagram that combines characteristics of both limiting cases while giving rise to qualitatively new collective states. Besides the gas, nematic-band, and polar file states, we uncover the emergence of \emph{active foams} – system-spanning fractal-like networks sustained by dynamically evolving particle streams. These structures arise solely from non-reciprocal vision-based interactions and are absent in both the short and long vision-range limits. For larger vision angles, the system self-organizes into a variety of aggregate morphologies, including condensates, rings, and multi-twist filaments, revealing a strong interplay between interaction range and anisotropic perception in shaping collective organization.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Eigenstate transitions and critical transport in 3D Aubry-André model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-14 20:00 EDT
Pragna Das, Lev Vidmar, Miroslav Hopjan
We numerically study spectral and wave-function properties, as well as time evolution, in finite-size commensurate approximations of the 3D Aubry-André model. We explicitly show, through scaling analysis, the existence of two critical points. One of the critical points is a localization-delocalization transition in real-space, similar to the critical point in the 3D Anderson model. The other is a localization-delocalization transition in a dual momentum space, which does not have any analog in the 3D Anderson model. We estimate their values from spectral measures, such as the gap ratio and the spectral form factor, as well as from wave-function measures, such as the inverse participation ratio and the participation entropy. Additionally, we demonstrate that both critical points exhibit hallmarks of critical points between quantum ergodicity and localization. First, the eigenstates and the eigenspectrum at the critical point fulfill the mutual universal relation between the eigenspectrum compressibility $ \chi$ and the eigenstate fractal dimension $ d^{(1)}$ [S. Jiricek et al., Proc. Nat. Acad. Sci. 123, e2518027123 (2026)]. Second, the dynamics of the wave packet at the critical point is governed by the critical dynamical exponent $ z$ , characterized by the spectral fractal dimension and the dimensionality of the lattice [M. Hopjan and L. Vidmar, Phys. Rev. Lett. 135, 060401 (2025)]. Thus, similarly to the 3D Anderson model, the critical dynamical exponent is sub-diffusive with the value of $ z=3$ .
Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
23 pages, 25 figures
Epitaxial Oxide Thin Films with High Entropy and Anomalous Crystallinity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Joseph Petruska, Christina M. Rost, Jon-Paul Maria, Saeed S. I. Almishal
Pulsed laser deposition (PLD) expands the compositional and structural possibilities of high-entropy oxide (HEO) thin films through far-from-equilibrium growth and kinetic arrest of metastable configurations. This review connects growth kinetics and epitaxial constraints to the roles of individual cations in shaping the resulting films. We focus primarily on rock salt MgCoNiCuZnO and its derivatives, with selected fluorite, spinel, and perovskite examples illustrating broader applicability. In MgCoNiCuZnO, Co valence and Cu coordination illustrate how chemistry and growth conditions jointly enable lattice tuning and coherent nanostructure formation, while aliovalent and size-misfit additions expand the accessible defect and compositional landscapes. These coupled degrees of freedom underpin anomalous crystallinity, the coexistence of extensive chemical disorder with exceptional crystalline quality and epitaxial order, including full coherence in selected systems, particularly rock salts grown on MgO. This combination opens opportunities to discover and engineer functional configurations in high-quality single-layer films and heterostructures.
Materials Science (cond-mat.mtrl-sci)
Quantum Localization in Geometric Complex Networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-14 20:00 EDT
Jan Lewenstein-Sanpera, Tobias Grass, M. Àngeles Serrano, Bruno Juliá-Díaz
Quantum localization, the phenomenon by which wave diffusion is halted, here understood as the superposition of propagating waves, can have many different origins, such as onsite random potentials in Anderson localization. However, some systems exhibit complex geometries and could potentially reproduce similar results without external potentials. In this work, we study how localization of single particle states is affected by the underlying topology of a simple but highly predictive complex network model: the geometric soft configuration model $ \mathbb S^1$ . By tuning the model’s temperature and heterogeneity parameters, we are able to generate different structural patterns and focus on the transition from a small-world to a non-small-world regime. Our study suggests that small-world networks tend to have extended states, which spread the whole system’s size, in contrast to non-small-world networks which tend to localize, showing how complex connectivity can play the role assigned to random energetic disorder.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
6 pages, 4 figures
Probing the wave-vector gap in nanoscale magnonics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Ondřej Wojewoda, Samer Kurdi, Toeno van der Sar, Daniel Schick, Sebastian Wintz, Alexei Maznev
Short-wavelength spin waves are central to miniaturizing magnonic devices and to studying exchange-dominated magnetization dynamics. Yet the wave-vector range between roughly 30 and 300 radians per micrometre has remained difficult to access experimentally, posing challenges for both excitation and detection. This Perspective reviews recent advances in emerging measurement techniques and discusses prospects for their future development. Optical and microwave techniques are restricted to the vicinity of the Brillouin-zone centre. Inelastic neutron, electron and resonant hard x-ray scattering cover the full Brillouin zone but lack the energy resolution needed for low-frequency magnons at intermediate wave vectors. This Perspective examines five emerging approaches that are beginning to close this gap: Mie-enhanced Brillouin light scattering, colour-centre magnetometry, magnon momentum microscopy, extreme-ultraviolet transient-grating spectroscopy, and time-resolved scanning transmission x-ray microscopy. For each, we discuss the physical principle, demonstrated capabilities, current limitations and prospects for development. Compared side by side, the techniques give complementary access to magnon frequencies, local stray fields, real-space dynamics and momentum-space distributions, and they differ in their sensitivity to coherent and incoherent excitations. We therefore discuss the main advantages and use cases of each technique and consider the practical requirements for addressing different scientific questions. We highlight opportunities for further development, including higher sensitivity, improved spatial and temporal resolution, and broader frequency and wave-vector coverage. Together, these advances could enable, for example, systematic studies of nonlinear magnon interactions at nanoscale wavelengths and investigations of emerging magnetic materials such as altermagnets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Spreading the Damage: How Heterogeneity Delocalizes Fracture in Polymer Networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Saleh Assadi, Zachary White, Radhika Joshi, Franck J. Vernerey
Fracture in polymer networks is strongly influenced by how network architecture and topology organize damage in space. Although these materials can sustain large deformations under homogeneous loading, they often fail in a brittle and flaw-sensitive manner once defects are present. Here we show that network heterogeneity is one key architectural parameter controlling this transition. Using a discrete mesoscale network model that explicitly resolves strand-level prestretch, force transmission, and irreversible bond scission, we demonstrate that heterogeneity in prestretch and strand lengths broadens crack-induced deformation, delocalizes bond rupture, and enlarges the fracture process zone. In polydisperse networks, increasing contour-length disorder broadens the prestretch distribution and systematically increases both toughness and the intrinsic length scale governing flaw sensitivity. Bimodal networks amplify this mechanism further through combined contrasts in prestretch and strand lengths, producing the largest damage zones and the highest toughness among the architectures studied. Inspired by the results, we derive a scaling estimate relating the emergent fracture-active length to the spatial range of crack-induced deformation and the logarithmic spread of strands’ remaining stretch to rupture.
Soft Condensed Matter (cond-mat.soft)
The authors Saleh Assadi and Zachary White have contributed equally to this work
Molecular-Level Evaluation of the Thermodynamic Properties of Charged Solutions from Submolar to Molar Ion Concentrations
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
The accurate estimation of the ionic activity coefficients is paramount for the characterization of the electrochemical reactions driving energy storage processes as well as the biological mechanisms involving ATP hydrolysis. The numerical evaluation of the ionic activity coefficients by computational methods is rendered difficult by the infinite dilution limit involved in the integral identity between the Helmholtz free energy and the equation of state of the electrolyte. By combining a recently introduced self-consistent Debye-Huckel formalism and its analytically tractable low density limit, we develop a computationally efficient approach enabling the accurate calculation of the free energy and the related thermodynamic functions of aqueous electrolytes over a broad range of ionic concentration and electrostatic coupling strength. Via comparison with numerical simulations and experimental data, it is shown that our approach can predict the salt dependence of the Helmholtz free energy, the entropy, and the ionic activity coefficients from the electrostatically driven submolar ion concentrations to the hard-core dominated molar density regime.
Soft Condensed Matter (cond-mat.soft)
Extreme anharmonicity determines the superionic transition in the prototypical antifluorite Li$_2$O
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Lorenzo Bastonero, Chiara Cignarella, Nicola Marzari, Lorenzo Monacelli
Superionic conductors are promising electrolyte candidates for all-solid-state batteries, thanks to their liquid-like ionic mobility. In the prototypical lithium-ion oxide superionic conductor with antifluorite structure, the high-temperature transition to the fast-ion regime has long been attributed to volume-driven harmonic phonon softening. However, this quasi-harmonic picture neglects the strong lattice anharmonicity inherent to the fast-ion regime, leaving the microscopic origin of the transition unresolved. Here, we apply non-perturbative lattice dynamics combined with a first-principles-accurate machine-learning interatomic potential to study the phase transition in Li$ _2$ O. We demonstrate that anharmonicity, rather than volume expansion alone as commonly assumed, plays the decisive role in determining the transition temperature and the underlying mechanism. Finally, we analyze the spectral properties using the time-dependent self-consistent harmonic approximation, revealing the breakdown of the quasi-particle picture in this material. The spectral function and the infrared response provide signtures of the phase transition that can be investigated experimentally using inelastic neutron or X-ray scattering and infrared spectroscopy. All these results establish the extreme anharmonicity of Li$ _2$ O near the superionic regime and provide a lattice-dynamic framework for understanding and engineering the fast-ion transition in this type of materials.
Materials Science (cond-mat.mtrl-sci)
An empirical model for deriving information on ion dynamics from $μ$SR data via the conventional Kubo-Toyabe function analysis
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
We present an empirical model that analytically relates the parameters of the extended Kubo-Toyabe (KT) function $ G_z^{\rm EA}(t;\Delta,\nu_{\rm i},Q)$ , which describes muon spin relaxation ($ \mu$ SR) induced by jump diffusion of ions using the Edwards-Anderson parameter $ Q$ , to those of the conventional KT function $ G_z^{\rm KT}(t;\Delta_{\rm KT},\nu_{\rm KT})$ that serves as an approximation of $ G_z^{\rm EA}(t)$ . The proposed formulae successfully reproduce the anomalous temperature dependences of the linewidth $ \Delta_{\rm KT}(T)$ and the fluctuation rate $ \nu_{\rm KT}(T)$ which are artifacts observed upon analyzing $ \mu$ SR data on ion diffusion using $ G_z^{\rm KT}(t)$ . Applying this model to $ \Delta_{\rm KT}$ and $ \nu_{\rm KT}$ published in the literature of battery materials yields activation energy $ E_{\rm i}$ and pre-exponential factor $ \nu_{\rm i0}$ in the Arrhenius equation for ion diffusion, $ \nu_{\rm i}(T)=\nu_{\rm i0} e^{-E_{\rm i}/kT}$ , that are in excellent agreement with those deduced using other techniques, transforming peculiar artifacts into a powerful diagnostic tool.
Materials Science (cond-mat.mtrl-sci)
10 pages, 8 figures (including those in Supplemental Material)
Deformation-induced spectral softening drives phase separation on non-spherical membranes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Avraham Moriel, Howard A. Stone
Models of curvature-driven membrane sorting couple composition directly to membrane bending elasticity. Here we show that shape deformations can destabilize a homogeneous state without this composition-dependent mechanical coupling. We analyze the eigenspectrum of the Laplace-Beltrami operator on deformed spheres analytically, and verify it numerically. As the deformation amplitude increases, the spectral degeneracy breaks, and the lowest nonzero eigenvalue decreases substantially. Using Cahn-Hilliard dynamics, we show that this eigenvalue softening provides a purely geometric route to phase separation.
Soft Condensed Matter (cond-mat.soft)
5 pages, 5 figures + Supplemental Materials
Nonrelativistic Optically-Induced Spin Torque in Noncollinear Magnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Manipulating spin using contactless and non-invasive optical approaches is one of the forefront topic in the modern spintronic science and technology. Prior studies on optically-induced spin reorientation usually scales with spin-orbit coupling strength, setting a limitation on composing heavy elements. In this work, we extend such a limit into nonrelativistic regime by exploring noncollinear magnetic configuration. Using a general spin group-theoretical investigation, we show how the symmetric operators in both spin and lattice spaces control the spin torque and quantum geometry of Bloch wavefunction–including both quantum metric and Berry curvature. We describe their site-resolved spin symmetries and unravel their selection rules. Furthermore, we adopt a Kagomé lattice model and a realistic material family to showcase the local spin torque under light irradiation. Since the nonrelativistic spin splitting usually spans on the order of electron-volt, significantly larger than typical spin-orbit induced splitting, the nonrelativistic light-induced spin torque is concomitantly much stronger. This work extends the previous opto-spintronics from relativistic to nonrelativistic limit, significantly broadening its realization platform.
Materials Science (cond-mat.mtrl-sci)
3 figures, PRL in press
Electronic Structure of a Delafossite Oxide CuAlO$_2$ in Comparison with CuCrO$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Kenta Takahashi, Ryo Kato, Mario Okawa, Tetsuji Okuda, Akira Yasui, Eiji Ikenaga, Kanta Ono, Noriaki Hamada, Tomohiko Saitoh
We investigated the electronic structure of a delafossite oxide CuAlO$ _2$ in comparison with CuCrO$ _2$ , using vacuum ultraviolet (VUV) and hard x-ray (HX) photoemission spectroscopy (PES) and band structure calculations within the local-density approximation +$ U$ scheme. Cu 3$ p! -! 3d$ resonant PES and Cu $ 2p$ core-level HX-PES give concrete evidence that the Cu valence in CuAlO$ _2$ is monovalent, which makes a sharp contrast to CuCrO$ _2$ that showed contradictory results depending upon probing methods [Yokobori \textit{et al.}, Phys. Rev. B \textbf{87}, 195124 (2013)]. We further noticed weak but detectable satellite structures due to Cu$ ^{2+}$ state in the Cu $ 2p$ HX-PES spectrum of CuCrO$ _2$ , surprisingly, without an observable main peak due to the Cu$ ^{2+}$ state. Comparisons between the valence-band HX-PES spectra and the band structure calculations revealed a significant amount of the Cu $ 4s$ and Al $ 3s$ /Cr $ 4s$ states in the valence band. The above results can reasonably be explained by the Cu $ 3d, 4s-$ Cr $ 3d$ charge transfer model that we previously proposed in the above paper, thereby demonstrating the critical role of empty $ 3d$ orbitals in the electronic structure of the copper delafossite oxides.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 6 figures
Journal of the Physical Society of Japan 88, 074701 (2019)
High-mobility spin transport mediated by indirect excitons in a van der Waals heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Zhiwen Zhou, W. J. Brunner, Luc M. Nguyen, C. A. Lozano, G. Mercado, L. H. Fowler-Gerace, L. V. Butov
Efficient spin transport with high spin mobility is of both fundamental and practical significance for spintronics. Spin can be transferred by moving particles. However, particle scattering limits spin transfer and prevents high spin mobilities. In this work, we study the kinetics of spin transport mediated by a quantum system of indirect excitons (IXs) in a van der Waals heterostructure composed of atomically thin transition-metal dichalcogenides (TMDs). This spin transfer mechanism allows for the realization of efficient spin transport characterized by a high spin mobility reaching 10$ ^5$ cm$ ^2$ /(eV$ \cdot$ s), which is orders of magnitude higher than that achieved via standard diffusive spin transport in TMD materials. The suppression of IX scattering enables high-mobility spin transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Vibrational Fingerprints of Competing Structural and Polar Phases in CuInP2S6
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Layered van der Waals CuInP2S6 crystals exhibit a rich sequence of temperature- and pressure-driven phase transitions, giving rise to multiple structural phases with distinct physical properties. Despite extensive experimental and theoretical efforts, unambiguous identification of these phases remains challenging because of their structural similarities and complex vibrational responses. In this work, we employ first-principles density functional theory calculations to systematically investigate the vibrational properties of the reference paraelectric C2/c and P-31c phases and their corresponding dynamically stable ferroelectric Cc and P31c phases, as well as the antiferroelectric P-1 and P-3 phases. From calculated phonon spectra and symmetry analysis, we determine the Raman- and infrared-active modes of each candidate structure and identify characteristic vibrational fingerprints that enable their phase determination through vibrational spectroscopy. Furthermore, using Porto notation, we establish polarization- and crystal-orientation-dependent Raman selection rules for different backscattering geometries and identify the modes that are expected to emerge or vanish under specific experimental configurations. Thus, our results provide a comprehensive theoretical framework for interpreting Raman and infrared measurements of CuInP2S6 and for reliably identifying its competing structural, ferroelectric, and antiferroelectric phases across temperature- and pressure-driven phase transitions.
Materials Science (cond-mat.mtrl-sci)
9 pages, 4 figures
Few-Magnon Universality beyond Contact Interactions in Long-Range Spin Chains
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-14 20:00 EDT
Quantum few-body systems exhibit a rich variety of phenomena that provide fundamental insights into universality. A paradigmatic example is the Efimov effect, in which an infinite tower of three-body bound states emerges with binding energies forming a geometric sequence. Motivated by advances in trapped-ion systems, recent theoretical work has predicted that the Efimov effect can arise in certain long-range quantum spin chains, where magnons exhibit a general dispersion $ \epsilon_k=u|k|^z$ with $ z\in(0.52,0.88)$ and interact through a contact potential. Nevertheless, whether Efimov universality persists in the presence of experimentally relevant long-range interactions between magnons remains unexplored. In this work, we address this issue by investigating the two- and three-magnon problems with a model interaction potential $ V(x)=V_0/(1+|x|^\beta)$ . Our results demonstrate that few-body universality persists for any $ \beta>1$ : In the two-magnon sector, the low-energy expansion of the scattering matrix near a two-body resonance agrees with the universal form predicted by contact-interaction theory. The three-magnon bound-state spectrum exhibits Efimov scaling, with a scaling factor consistent with the theory. We further highlight the experimental relevance of our model, which can be readily realized in trapped-ion systems. Our results pave the way for quantum simulations of universal few-body physics beyond the traditional paradigm of nonrelativistic particles.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
10 pages, 4 figures
Length-scale dependence of collective time reparameterization in swap dynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Swap Monte Carlo dramatically accelerates the equilibration of deeply supercooled liquids while preserving the equilibrium Boltzmann distribution. Recent work has argued that swap and other accelerated algorithms act by reparameterizing time: different dynamics follow the same slow relaxation process, but with different clocks. Here we test this idea in a continuously polydisperse glass former. We confirm that mean collective overlaps satisfy an approximate time reparameterization, in agreement with earlier results. However, the associated clock depends systematically on the collective probe length and on the relaxation stage. Thus the observed collective collapse does not define a unique, observable-independent material time. Over the numerically accessible $ \alpha$ -relaxation regime, swap changes not only the rate of relaxation, but also its length-scale dependence. The resulting collective reparameterization is therefore only approximate and does not establish an exact dynamical equivalence between swap and reference relaxation.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Chirally pinned flat bands, helical minibands, and bias-controlled topology of Jackiw-Rebbi states in a periodically modulated Dirac mass texture
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Flat bands amplify interactions into correlated phases, and topological bound states are robust by principle; combining the two in a model that is both exactly analyzable and experimentally accessible is therefore especially desirable. Here we show that a square-lattice model with a slowly modulated Dirac mass texture, $ m(x)=m+m_0\cos(2\pi x/L)$ with $ L$ up to hundreds of sites, provides such a setting, without engineered geometries, lattice-scale textures, or long-range hoppings. Exact nesting reduces the problem, independently at each transverse momentum $ k_y$ , to a $ 1+1$ dimensional Dirac Hamiltonian with a position-dependent mass: every simple zero of $ m(x)$ binds Jackiw-Rebbi zero modes, and the two walls of a period form an effective Su-Schrieffer-Heeger ring. The model interpolates between a chirally pinned flat band at large $ L$ , a helical miniband whose nodes are enforced by a boundary phase of the ring, and a bias-dimerized regime in which the sign of the bias sets a winding number. A central result is that the miniband bandwidth is not a single scale: a max-min measurement conflates three widths of different origin, the helical height $ W_{\rm JR}$ exponential in the period, the zone-edge upturn $ W_{\rm edge}\propto L^{-2/3}$ dominating at large $ L$ , and a bias bump exponential in $ L$ , so the flat band is robust against bias in the thermodynamic limit. We analyze two lattice realizations, a two-orbital model with modulated inter-orbital hybridization and a single-orbital bond-order texture sharing the nodal physics while leaving the van Hove points gapless, and propose experiments on cold-atom superlattices, Kekule-ordered graphene, STM designer lattices, and microwave arrays.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Quantum Gases (cond-mat.quant-gas)
12 pages, 5 figures
Self-Avoidance Governs Re-entrant Coil-Globule Transition of Inertial Active Brownian Ring Polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Rakesh Palariya, Arindam Panda, Roland G. Winkler, Sunil P Singh
Active matter systems composed of self-propelled entities exhibit a wide range of out-of-equilibrium phase behaviors and collective dynamics. Assemblies of active particles, e.g., in a linear structure, are particularly interesting, as they exhibit an intriguing interplay between activity and geometrical restrictions due to self-avoidance and entanglements. Using Langevin dynamics simulations of an active Brownian ring polymer with translational and rotational inertia, we uncover an inertia-driven re-entrant coil-globule transition in the absence of any attractive interactions. We show that rotational inertia plays a paramount role, leading, in the globular state, to spontaneous, nonzero, radially outward polarization of the active forces. Self-avoidance and entanglements break the rotational symmetry of active beads and effectively stabilize the globular states. The transition becomes increasingly sharp with increasing rotational inertia, yielding highly compact globular conformations at intermediate activities, whereas at high activity the polymer re-expands into a coil state. Scaling of the radius of gyration reveals crossovers from self-avoiding, phantom-like to compact-globular structures. Further, rotational inertia enhances transport properties, with an intermediate activity-induced Rouse-type bead diffusion and a long-time diffusion coefficient displaying a power-law dependence on the moment of inertia. Our study establishes a purely inertia-induced mechanism for controlling the collapse of active polymers, arising from spontaneous active-force polarization and self-avoidance.
Soft Condensed Matter (cond-mat.soft)
14 pages , 10 figures
Field-driven phase transition crossover in kagome antiferromagnet Mn$_{3-x}$Co$_x$Sn
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Mn$ _3$ Sn exhibits a complex magnetic phase diagram with multiple symmetry-breaking phenomena. Minute electron doping at the Mn site breaks the kagome lattice symmetry in Mn$ _3$ Sn. In this work, we exploited this to tune the order of the magnetic phase transition using magnetocaloric effect in Mn$ _{3-x}$ Co$ _x$ Sn single crystals. Pristine Mn$ _3$ Sn shows metallic behaviour with a spin-reorientation transition at 278 K, which shifts to 175 K upon Co doping. Additionally, Co doping also induces a weak-ferromagnetic transition near $ \approx 210$ K. The effect of Co doping results inverse to conventional magnetocaloric effect, with enhanced magnetic entropy change. Further, the scaled entropy change reveals a field-driven magnetic phase transition crossover from first order to second order in Mn$ _{2.75}$ Co$ _{0.25}$ Sn crystal. Based on experimental data, a new phase diagram is constructed, depicting the field evolution of various magnetic orders.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
10 pages, 6 figures
Orbital cancellation and reentrant localization in a quasiperiodic trimer ladder
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2026-10-14 20:00 EDT
Xin Wang, Pei-Jie Chang, Quanfeng Lu, Muxi Zheng, Dong Ruan, Gui-Lu long
Uniform orbital detuning can restore spatial extent even as quasiperiodic modulation strengthens. In a trimer ladder with fixed hoppings and orbital modulation signs, increasing detuning and modulation amplitude together drives successive avoided crossings that redistribute orbital weights, suppressing the projected onsite potential in both lower molecular bands while leaving the third strongly modulated. Complete-band participation scaling supports two reentrant high-participation windows, with wave-packet propagation corroborating spatial recovery at representative controls over the studied sizes and times. These diagonal cancellations leave residual interband modulation, which generates a self-energy whose magnitude depends on the molecular level separation. Gaussian quadrature improves convergence of closed-walk determinant estimates used to cross-check energy-resolved attenuation. Comparing the coupled and decoupled ladders under the same finite-size participation criterion shows that restoring the full off-diagonal modulation narrows both sampled windows, with a larger absolute contraction of the second.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Defining Thixotropy
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Yogesh M. Joshi, Ronald G. Larson
Originally coined 100 years ago to represent a shear-reversible sol-gel transition, the range of the term “thixotropy” has gradually expanded to encompass time-dependent changes in viscosity. Since this risks confusing “thixotropy” with ordinary nonlinear viscoelastic behavior, in this work we seek simple, historically faithful, quantifiable, and experimentally testable definitions of “thixotropy” that avoid this confusion. By analysing both historical tradition and published experimental data, we arrive at three complementary definitions. Definition 0 provides an idealized, purely inelastic reference useful primarily for recognizing thixotropy in a constitutive equation. Definitions 1 and 2, which are more practical, require, respectively, unusually large strains to reach steady state, and unbounded growth of the material relaxation time during rest. Definition 1 can apply in either shear-rate or stress-controlled modes, with the latter encompassing the so-called “viscosity bifurcation.” These criteria are tested across diverse materials that we identify as thixotropic based on their responses clearly exceeding their viscoelastic reference scales. The framework is deliberately phenomenological and does not require specific microscopic mechanisms, allowing diverse materials to be described within a common rheological language, as is typical for rheological terminology. We believe that these definitions provide a practical framework for assigning thixotropy a more definite place in rheological taxonomy.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
71 pages, 13 figures
Wilson-loop formulations of the spin polarization and the spin Chern number
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Kiminori Hattori, Ryuki Uchida
In this paper, we derive the spin polarization and the spin Chern number in momentum and real spaces in terms of the Wilson loop in each spin sector. For these derivations, the spin matrix in the subspace of occupied or unoccupied states is generalized by the unitary rotation to prevent the spectral gap from closing. In the presence of a finite spin gap, the spin eigenvectors recompose the eigenstates of the Hamiltonian in two spin sectors. A dimensional reduction leads to the charge polarization in each spin sector in terms of the Wilson loop along the effective Brillouin zone (BZ) in one dimension (1D). A linear combination of the charge polarizations defines the spin polarization, which naturally quantifies the spin Chern number in momentum space. It is also shown that the spin Chern number is directly derived from the local Wilson loops on a discrete 2D BZ. The theoretical treatment is further generalized for real space in a supercell framework, which can deal with ordered and disordered systems in a unified manner. In this framework, the spin Chern number in real space is formulated in terms of the Wilson loop around the BZ boundary. These formulations are used to numerically evaluate topological phases in the Bernevig-Hughes-Zhang model. Numerical results show an equivalence of the spin Chern number and the $ {\mathbb{Z}_2}$ index.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 8 figures
Symmetry Condition and Mechanism for the Anomalous Hall Effect in Odd-Parity Magnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Xun-Jiang Luo, Su-Qi Zhang, Yi-Dong Liu, Yong-Ting Shi, Ding-Fu Shao, Mingliang Tian
The anomalous Hall effect (AHE) in unconventional magnets has attracted considerable attention. A giant AHE has recently been observed in the candidate $ p$ -wave magnet Gd$ _3$ (Ru$ _{1-\delta}$ Rh$ _{\delta}$ )$ _4$ Al$ _{12}$ [Nature 646, 837(2025)], while its theoretical interpretation invokes a spontaneous magnetization to break time-reversal symmetry ($ \mathcal{T}$ ), although the magnetic order itself already breaks $ \mathcal{T}$ . Consequently, the microscopic origin of the AHE in odd-parity magnets (OPMs) remains an open question. Here we establish the symmetry condition and microscopic mechanism for the AHE in OPMs. Since the OPM order is classified by the spin group whereas the AHE is governed by the magnetic group, the AHE is allowed only when the magnetic point group is ferromagnetic; conversely, it is forbidden whenever the effective time reversal $ \mathcal{T}\tau$ (with $ \tau$ a fractional translation), which is essential to the realization of the OPM, is preserved. Microscopically, OPMs generically host a hidden Zeeman field (HZF) rooted in this intrinsic $ \mathcal{T}$ breaking, and its interplay with spin-orbit coupling (SOC) generates the AHE without any external field. We demonstrate this picture with models on the square, honeycomb, and kagome lattices. In particular, a square-lattice helimagnet with sublattice-resolved SOC maps exactly onto an anisotropic Rashba–Zeeman model, whose Zeeman term is nothing but the HZF and directly yields the AHE. Our results establish the symmetry condition for the AHE in OPMs and identify the HZF–SOC interplay as a general route to realize it.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages,2 figures
Pressure Evolution of the Superconducting Order Parameter of Kagome Superconductor CsV3Sb5
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Haiyan Zuo, Wangju Yang, Zhifan Wu, Yuqing Zhao, Qiuxia Chen, Weiming Lao, Yangpeng Qi, Hechang Lei, Haizi Cong, Cong Ren
Kagome superconductors AV3Sb5 (A = K, Rb, Cs) offer an outstanding platform for exploring the interplay among charge-density-wave (CDW) order, superconductivity (SC), and nontrivial topological electronic states. For CsV3Sb5, moderate hydrostatic pressure induces a double-dome superconducting phase diagram while monotonically suppressing the CDW phase, which signals an unconventional coupling between SC and CDW. Nevertheless, the microscopic nature of the pressure-modulated superconducting state and its relationship with CDW order remain poorly understood. Here we employ soft directional point-contact spectroscopy (SDPCS), combined with superconducting resistive measurements, to probe the superconducting order parameter of CsV3Sb5 under hydrostatic compression. Our anisotropic PCAR measurements resolve two distinct s-wave superconducting gaps along the c-axis and a strongly anisotropic gap within the ab plane. Two-band Blonder-Tinkham-Klapwijk (BTK) fits to the c-axis spectra yield a large gap satisfying 2Delta1/kBTc > 3.52 and a small gap with 2Deltas/kBTc < 3.52. The spectral-weight-averaged coupling ratio 2Deltaavg/kBTc is enhanced in the pressure window between P1 and P2, suggesting that pressure-induced modifications of the low-energy electronic structure may contribute to the evolution of superconductivity. For ab-plane junctions, the superconducting gap anisotropy is gradually suppressed above P1, accompanied by the emergence of a pronounced peak-dip-hump structure suggestive of enhanced coupling between superconducting quasiparticles and a bosonic excitation. These results shed new light on the intricate entanglement between CDW and SC in kagome superconductivity.
Superconductivity (cond-mat.supr-con)
Universal Boolean Computation in Negatively Coupled Circle Map Lattices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Priyanka D. Bhoyar, Prashant M. Gade
We investigate the computational capabilities of a one-dimensional lattice of negatively
coupled circle maps in its traveling wave regime. We interpret propagating waves as information carriers and exploit their interactions to implement Boolean logic. The logical states are encoded by the propagation direction of the traveling waves, while the presence or absence of a wave at a designated output location represents the logical output. Using controlled wave collisions, we demonstrate the realization of NAND and NOR gates along with other basic gates. Since NAND and NOR operations are functionally complete, the results establish that the traveling wave regime of the negatively coupled circle-map lattice supports universal Boolean computation in principle. The demonstrated logical operations remain valid over a finite range of the coupling strength \epsilon and map parameter \omega, indicating robustness of the computational scheme to parameter variations. Our results therefore demonstrate that computational functionality can emerge from the collective nonlinear dynamics of a coupled map lattice, providing a con- nection between the dynamical properties of traveling wave states and collision based information processing.
Statistical Mechanics (cond-mat.stat-mech), Chaotic Dynamics (nlin.CD), Pattern Formation and Solitons (nlin.PS), Instrumentation and Detectors (physics.ins-det)
Dynamical-state switching controls active microrod navigation in porous media
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Ana Cazorla, Maria L. Jimenez, Raul A. Rica-Alarcon, Carla Fernandez-Rico, Laura Alvarez
Adaptive search and travel strategies enable biological swimmers to explore complex environments, but remain difficult to encode in minimal synthetic microswimmers. Here, we unveil multiple dynamical and orientational states of rod-like Janus microswimmers actuated via electric fields: planar active, oriented chiral and persistent rods. We discover a hidden dynamical state after pre-orienting them, which allows us to switch on demand from strong chiral to persistent motion. We harness this phenomenological orientation and chirality switch for exploration in microstructured porous arrays. Here, strong chirality promotes local scanning but drives circular trapping and poor net displacement, whereas the pre-aligned dynamical state enables efficient obstacle sorting, and trap escape. Comparing experiments with simulations of active Brownian particles in the very same experimentally-extracted obstacle geometries, we quantify navigation efficiency via first-passage time statistics, revealing how chirality tuning optimizes the trade-off between local exploration and long-range transport.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph)
Derjaguin-corrected Kelvin equation for finite open slits
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
We formulate a Derjaguin-corrected Kelvin equation for phase transitions in finite open slits. In such pores, capillary condensation is modified by the finite wall length because the condensed phase is bounded by two terminal menisci pinned at the slit ends. Starting from the macroscopic generalized Kelvin equation, we introduce a scaling approximation which replaces the implicit edge-contact-angle condition by a closed analytic expression while preserving the exact limiting behaviours. We then incorporate mesoscopic wetting-layer contributions into the finite-slit free-energy balance. The single-wall contribution naturally separates into a planar Derjaguin term and a residual finite-length correction controlled by the competition between the wall length $ H$ and the parallel correlation length $ \xi_\parallel$ . The resulting equation reduces to the standard Derjaguin-Kelvin equation for infinitely long slits and to the macroscopic finite-slit Kelvin equation when adsorbed layers are absent. Explicit forms are derived for long-ranged dispersion forces and for short-ranged forces. The theory is tested using classical density functional theory for finite slits with attractive Lennard-Jones walls and hard walls, corresponding respectively to capillary condensation and its drying analogue, capillary evaporation. The Derjaguin-corrected theory substantially improves on the purely macroscopic prediction, capturing both the correct infinite-slit limit and the observed dependence on wall length. For the short-ranged hard-wall system, the agreement with DFT remains nearly quantitative even for very narrow slits.
Soft Condensed Matter (cond-mat.soft), Other Condensed Matter (cond-mat.other), Statistical Mechanics (cond-mat.stat-mech)
Phys. Rev. E 114, 045502 (2026)
Angle-Resolved Photoemission as a Sensitive Probe of Surface Quality: Sputtered versus Annealed Cu(001)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Hyeonhee Na, Jeonghwan Oh, Jinju Lee, Hanjun Sim, Myeongun Go, Jimin Sohn, Jeonggu Kang, Byungmin Sohn
Angle-resolved photoemission spectroscopy (ARPES) requires a well-ordered surface, whose quality is routinely judged from low-energy electron diffraction (LEED) and x-ray photoelectron spectroscopy (XPS). We compare LEED, XPS, and ARPES of a Cu(001) single crystal measured in situ at four stages of surface preparation: as-prepared, after aging for 24 h at 6 K, after Ar$ ^+$ sputtering, and after annealing. The sputtered and annealed surfaces show nearly identical $ (1\times1)$ LEED patterns and Cu 2$ p$ core levels, but the sputtered surface yields a momentum-independent ARPES spectrum, and the band dispersion recovers after annealing. We attribute this contrast to how each probe responds to sputtering-induced defects: LEED reflects the average lattice, which remains periodic, whereas ARPES reflects the electronic states, whose crystal momentum is no longer well defined. Our results indicate that a sharp LEED pattern and clean core-level spectra do not guarantee a surface suitable for ARPES.
Materials Science (cond-mat.mtrl-sci)
6 pages, 6 figures
Thermal softening of the yield stress in glasses with different stability
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
The yielding of amorphous solids has been extensively studied in the athermal limit, but the influence of thermal fluctuations is much less understood, in particular for glasses of different stability. Using molecular dynamics simulations of a model glass where the swap Monte Carlo algorithm can be employed, we study the yield stress at finite temperature and shear rate, both in steady flow and at shear start-up, over a broad range of glass stability. Thermal fluctuations soften both the dynamic yield stress in steady state and the start-up yield stress. In all cases, the temperature dependence is compatible with the $ T^{2/3}$ law expected for thermally activated yielding near a saddle-node instability, with no systematic dependence of the exponent on stability or shear rate. Extrapolations to zero temperature recover the athermal yield stresses. The amplitude of the softening at start-up, by contrast, depends strongly on stability: highly stable glasses are much less sensitive to temperature than poorly annealed ones. A description of yielding at finite temperature must therefore account explicitly for the stability of the glass.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
14 pages, 6 figures. Submitted to J. Phys. A: Mathematical and Theoretical to its Focus Collection “Driven Amorphous Matter: Deformation, Activity, Aging and Memory”
Decoupling Trap States in Amorphous Oxide Semiconductor Transistor Using a Conductive-Semiconducting-Conductive MOS Structure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Kai Chen, Wei Zhang, Xuanyao Fong, Shengman Li, Yunlong Li
We propose a novel amorphous oxide semiconductor (AOS)-based conductive-semiconducting-conductive (CSC) MOS test structure to effectively sense, discriminate, and analyze distinct trap-induced conductance losses in AOS transistors. In conventional test structures, non-ideal metal-AOS contacts convolute the conductance loss generated by various trap states. The CSC architecture mitigates these contact-related artifacts, enabling the decoupling of interface states and shallow states. Furthermore, the contributions from leakage, series resistance, and device-geometry effects are identified and calibrated. Our results yield bias-resolved trap profiles and reveal three distinct regimes: (1) In the depletion region, interface states dominate the conductance loss. These states exhibit sub-microsecond time constants and their density increases slightly with deeper depletion, which is associated with donor-like states. (2) From weak to moderate accumulation, shallow states become the primary contributor, displaying a Gaussian-like volumetric density-of-states distribution with response times spanning from microseconds to nanoseconds. (3) In the strong accumulation regime, interface states regain dominance with an increased state quantity, while their time constants remain invariant. These bias-resolved profiles clarify how different trap populations impact AOS transistors under distinct operating conditions, providing intuitive metrics for understanding reliability degradation. Consequently, the CSC structure offers a simple, scalable, and robust platform for trap characterization in AOS transistors.
Materials Science (cond-mat.mtrl-sci)
4 pages, 10 figures
Thermally Enhanced Pseudo-Goldstone Spin Gap in the Isotropic Helimagnet ZnCr$_2$Se$_4$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
N. D. Andriushin, A. Sanders, J. Reuther, D. C. Peets, P. Steffens, A. Hiess, J. Lass, L. Prodan, V. Tsurkan, V. Felea, D. S. Inosov
In magnetically ordered systems, the spin gap in the magnon spectrum is normally expected to decrease on warming and close at the transition out of the long-range order. The presence of a pseudo-Goldstone gap is commonly associated with nonlinear terms in spin-wave theory. However, its precise origin and detailed properties can vary and remain under debate. Here we show by means of inelastic neutron scattering that the pseudo-Goldstone gap in the Heisenberg helimagnet ZnCr$ _2$ Se$ 4$ exhibits an atypical, nonmonotonic temperature dependence: the gap increases over much of the ordered phase before closing near $ T\mathrm{N}$ . These results align with recent spin-dynamic simulations based on an effective quartic potential in an isotropic system~[Phys. Rev. B \textbf{113}, L220411 (2026)]. As the pseudo-Goldstone spin gap in ZnCr$ _2$ Se$ _4$ is dominated by quantum effects at subkelvin temperatures, its characteristic growth on warming is caused by thermal fluctuations.
Strongly Correlated Electrons (cond-mat.str-el)
Photon echo from Maki-Thompson interference in a fluctuating s-wave superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
We study theoretically the nonlinear optical response of a fluctuating s-wave superconductor driven by two successive terahertz pulses. We show that the response exhibits a photon echo signal that arises from the quantum interference between the time-reversed electron and hole trajectories in the Maki-Thompson process. By contrast, the transport of the fluctuating Cooper pairs responsible for the Aslamazov-Larkin conductivity does not generate an echo. The photon echo signal can be readily measured using terahertz two-dimensional coherent spectroscopy, highlighting its potential to distinguish different fluctuation conductivity mechanisms.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 5 figures
Modelling the dynamics of the martensitic transformation in Ni$_2$MnGa with machine-learning force-fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Markus E. Gruner, Yulia Klunnikova, Mike J. Bruckhoff, Konstatin P. Skokov, Olga N. Miroshkina
The martensitic transformations in stoichiometric Ni$ _2$ MnGa and related Heusler alloys are governed by a delicate interplay between electronic structure, magnetism, and lattice dynamics. While density functional theory (DFT) has successfully mapped the energy landscape of modulated martensites, it remains computationally prohibitive for capturing finite-temperature dynamics across relevant length and time scales. Here, we bridge this gap by constructing DFT-trained machine-learning force-fields (ML-FF) interpolated from ab initio molecular dynamics. We demonstrate that ML-FF trained on DFT data can reproduce key features of Ni$ _2$ MnGa, including the soft TA$ _2$ phonon and a preference for nanotwinned martensites. Using classical molecular dynamics simulations, we explore the impact of adaptive nanotwinning on the austenite-martensite transition, which facilitates the dynamics of both, forward and backward transformation. We demonstrate, that the negative twin boundary energy along the entire transformations path predicted by DFT for $ T=0$ , supports the formation of ordered modulated martensites at finite temperatures. Our results pave the way for large-scale simulations of magnetic shape memory alloys with near-DFT accuracy.
Materials Science (cond-mat.mtrl-sci)
12 pages, 7 figures
Deterministic positioning accuracy of B centers in hBN by electron irradiation
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-14 20:00 EDT
A. Núñez Marcos, C. Arnold, J. Barjon, S. Buil, J.-P. Hermier, A. Delteil
Hexagonal boron nitride (hBN) is a promising material platform for quantum technologies, enabling both the realization of nanophotonic devices and the hosting of point defects that act as high-quality single-photon emitters (SPEs). Among these defects, B centers, which reproducibly emit at 436 nm, can be generated individually at predefined positions using electron beam irradiation, a crucial capability for top-down quantum photonics. Yet, the spatial accuracy of emitter creation strongly conditions the potential applications. Here, we generate arrays of individual B centers in a scanning electron microscope (SEM) with in-situ cathodoluminescence (CL) monitoring. We characterize the sources of random deviations from the target positions to identify the limitations to their deterministic positioning. In particular, we measure the distance between the electron beam and the emitter at the moment the emitter is created based on CL mapping. This approach provides a direct estimation of the spatial extent of the beam-emitter interaction. We find this contribution to be the main constraint to the emitter fabrication accuracy, yielding a standard deviation of 27 nm. Additional contributions, primarily from the finite density of UV-emitting carbon dimer precursors, increase the overall positional standard deviation to 40 nm. Our results highlight the possible improvements to the B center creation technique to reach sub-10 nm accuracy.
Other Condensed Matter (cond-mat.other), Quantum Physics (quant-ph)
Molecule-intercalated van der Waals Josephson junctions uncover complex multiband superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Daniel Margineda, David Caldevilla-Asenjo, Covadonga Álvarez-García, Daniel Tezze, Raul Arenal, Maxim Ilyn, Celia Rogero, Luis E. Hueso, Marco Gobbi
Intercalation of molecular species provides a route to tailor the electronic structure in van der Waals superconductors, yet intercalated compounds have rarely been integrated into phase-sensitive quantum devices. Here, we realize hybrid molecular Josephson junctions based on TaS2/NbSe2 heterostructures. Selective intercalation of the TaS2 electrode induces monolayer-like Ising superconductivity, while the junctions exhibit asymmetric Fraunhofer interference, field-induced and spontaneous Josephson diode effects. The zero-field diode disappears upon reversing the electrode stacking and re-emerges after intercalating the lower NbSe2 electrode. These findings indicate that the hybrid superconducting electrode hosts unconventional superconductivity underlying the nonreciprocal transport, while molecular intercalation acts as a tuning knob for its internal phase structure. This behavior is consistent with a time-reversal-symmetry-breaking multiband superconducting state characterized by a nontrivial relative phase between superconducting condensates. Our results establish hybrid molecular Josephson junctions as a quantum-device platform for phase-sensitive investigation and integration of molecularly engineered superconductors, opening opportunities to uncover and engineer unconventional superconducting phases.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Emergence of Nonlocal Hydrodynamics in Many-Body Radiative Heat Transport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Mauricio Gomez Viloria, Florian Herz, Riccardo Messina, Philippe Ben-Abdallah
We develop a nonlocal hydrodynamic theory of radiative heat transport in many-body systems by coarse graining their microscopic electrodynamic interactions. Long-range radiative exchange naturally generates a spatially nonlocal constitutive relation in which the heat current at a given position depends on temperature gradients over an extended region, while energy conservation retains its local conservative form. Fourier transport emerges as a controlled long-wavelength limit when the interaction kernel has a finite second spatial moment. When this moment fails to converge, spatial nonlocality survives coarse graining and gives rise to non-Fourier transport. The resulting framework establishes a systematic bridge between discrete many-body fluctuational electrodynamics and a continuous description of radiative heat transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Scalable Quantum Monte Carlo for Shannon-Rényi Entropy: An Experiment-visitable Probe of Quantum Phases and Criticality
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Dong-Xu Liu, Zhe Wang, Zenan Liu Yi-Ming Ding, Zheng Yan
The Shannon-Rényi (SR) entropy characterizes the probability distribution of many-body wave functions in a chosen basis and is directly accessible from single-shot measurement snapshots in cold-atom experiments, yet its theoretical evaluation in interacting systems carries exponential cost. Here we construct a field-theoretic spacetime manifold for the SR entropy in which $ q$ replicas are glued at the imaginary-time boundaries, recasting it as a ratio of generalized partition functions amenable to large-scale quantum Monte Carlo simulation. On this basis we develop a reweight-annealing framework with two complementary strategies: a virtual-parameter scheme interpolating between unglued and fully glued limits via binomial-weighted partial gluing, and a real-parameter scheme using a physical coupling constant as the annealing variable within stochastic series expansion. Both reduce the computational cost from exponential to polynomial. Most importantly, we establish for the first time a finite-size scaling theory for the SR entropy near a quantum critical point, $ S_q=a(g)L^2+S_q^0\left((g-g_c)L^{1/\nu}\right)$ ; data collapse of its first derivative yields the correlation-length exponent $ \nu$ for both the O(3) and Ising universality classes, realized in the spin-$ \frac{1}{2}$ columnar dimerized Heisenberg model and the bilayer Heisenberg-Ising model. The same simulations extract the Goldstone-mode count $ N_G=2$ and the $ Z_2$ ground-state degeneracy $ \ln 2$ from subleading terms. These results elevate the SR entropy to a standalone, order-parameter-free diagnostic of quantum criticality with the same scaling status as the entanglement entropy, and close the loop between theory and quantum simulation by enabling quantitative benchmarking of experimental snapshots from state-of-the-art quantum simulators.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
11 pages, 5 figures
Superconductivity from altermagnetic fluctuations: the crucial role of sublattice polarization
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Mats Barkman, Andreas Kreisel, Brian M. Andersen
Unconventional superconductivity in correlated systems often appears in the vicinity of a magnetically ordered state. This situation is also relevant for altermagnets, characterized by a nonrelativistic spin-split electronic structure in the presence of Néel order. Many proposed altermagnetic candidates, however, never cross the magnetic instability. We study superconductivity arising from altermagnetic fluctuations in such systems and show that the sublattice polarization (SLP) of the normal-state bands plays a pivotal role in determining the superconducting state. SLP, an inherent property of altermagnetic band structures that persists even without magnetic order, prevents Cooper pairs from forming between different sublattices. This suppresses pairing mediated by the nearest-neighbor antiferromagnetic exchange, which favors spin-singlet superconductivity, and leaves longer-range same-sublattice bonds dominant. When the next-nearest-neighbor exchange is ferromagnetic, as expected for frustration-free Néel order, this results in spin-triplet superconductivity. This mechanism is fundamentally different from that in altermagnets with long-range Néel order, where the spin-split Fermi surfaces favor equal-spin pairing. Finally, when longer-range interactions in the disordered phase instead favor singlet pairing, SLP leads to singlet states with characteristic properties distinct from nearest-neighbor pairing states.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
16 pages, 16 figures
Optically driven ultrafast lattice contraction in a topological crystalline insulator
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-14 20:00 EDT
M. H. Berntsen, W. Chen, D. Phuyal, J. Wu, A. Grubišić-Čabo, M. Dendzik, Q. Guo, A. Orthaber, C. Li, R. M. Geilhufe, J. Weissenrieder, O. Tjernberg
The ability to dynamically control topological order remains a central challenge in the exploration of quantum materials. Here, we investigate the lattice and electronic response of the topological crystalline insulator (TCI) Pb$ {1-x}$ Sn$ x$ Se to ultrafast optical excitation using time- and angle-resolved photoemission spectroscopy (tr-ARPES) in combination with X-ray diffraction (XRD) and first-principles calculations. Static XRD measurements establish the lattice constant as the key control parameter for the topological transition, with a critical value $ a\mathrm{c}=6.073$ Åseparating the normal-insulator and topological phases. Despite generating electronic temperatures far above the topological-to-normal transition temperature $ T\mathrm{c}$ , optical excitation in the TCI phase does not induce a phase transition. Instead, it drives an ultrafast lattice contraction of $ \Delta a \approx -0.45$ pm within less than 1 ps that counteracts thermal expansion and prevents the system from reaching $ a_\mathrm{c}$ . The optical excitation therefore pushes the system deeper into the topological phase, providing a direct explanation for the absence of an optically driven transition. Total-energy calculations reveal that this behavior originates from the band inversion in the topological regime, which reverses the character of the photoinduced charge transfer and transiently strengthens atomic bonding. These findings identify band inversion as a mechanism that fundamentally alters the nonequilibrium lattice response, with general implications for ultrafast optical control of topological materials.
Other Condensed Matter (cond-mat.other)
Theoretical Investigation of Oxygen-Vacancy Diffusion in SrTiO$_3$ using Neural Network Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Kazutaka Nishiguchi, Ryota Yamamoto, Seiichiro Ten-no
Oxygen-vacancy formation and diffusion play important roles in determining the electronic and atomic transport properties of SrTiO$ _3$ (STO). Accurate analysis of such point defects requires sufficiently large-scale and long-time molecular dynamics (MD) simulations; however, direct investigations of oxygen-vacancy dynamics using {\it ab initio} MD (AIMD) based on density functional theory (DFT) are limited to relatively small systems and short time scales because of their high computational cost. In this study, we develop a neural network potential (NNP) for pristine and oxygen-deficient STO using a reference dataset generated from AIMD simulations. The trained NNP model accurately reproduces the DFT reference energies, atomic forces, and virials for both pristine STO and STO containing an oxygen vacancy. The NNP also reproduces the supercell-size dependence of the total energies and oxygen-vacancy formation energies, including the formation energy extrapolated to the dilute limit. Large-scale and long-time MD simulations using the NNP (NNP-MD) are then performed to investigate oxygen-vacancy diffusion. The resulting oxygen-vacancy diffusion coefficients show substantially better agreement with experimental data than those obtained from conventional classical MD simulations. An Arrhenius analysis yields an oxygen-vacancy migration enthalpy of 0.64 eV, in close agreement with the experimental value of 0.67 eV. These results demonstrate that NNPs trained on first-principles data provide an accurate and computationally efficient framework for investigating defect formation and long-time vacancy transport in perovskite oxides.
Materials Science (cond-mat.mtrl-sci)
18 pages, 6 figures. to be submitted in The Journal of Physical Chemistry C
Bogoliubov excitations of a Bose-Einstein condensate in the presence of the non-Hermitian skin effect
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-14 20:00 EDT
Carlo Panu, Ulf Peschel, Oleg A. Egorov, Elena A. Ostrovskaya, Eliezer Estrecho
The non-Hermitian skin effect is one of the most remarkable topological features of non-conservative physics. It causes a macroscopic accumulation of states at the boundaries of a confined system, opening new ways for controlling and directing waves in non-Hermitian settings. This effect has recently been observed in experiments with Bose-Einstein condensates of exciton polaritons and ultracold bosonic quantum gases. The underlying physics is captured by a mean-field Hamiltonian with a trapping potential and an imaginary gauge field. While prior work has examined the effect of the imaginary gauge field term on the condensate itself, its effect on the collective excitations on top of the condensate remained unexplored. Here, we develop a new theory for the Bogoliubov excitations in a non-Hermitian framework and systematically study their spectrum across different interaction regimes. By analysing the position expectation values, we find that while the repulsive interactions oppose the localisation of the condensate due to the skin effect, the excitations remain strongly affected by the imaginary gauge field. As a consequence, in the presence of harmonic confinement, we predict a strong shift in the dipole oscillation frequency, which can be observed in experiments. This is in contrast to Hermitian systems, where this frequency is fixed by the trap dimensions. Furthermore, we develop a consistent second-quantised field theory of the collective excitations in this non-Hermitian system. Strikingly, we find that a second-quantised treatment removes the shift of the dipole oscillation frequency entirely. This intriguing discrepancy between the two theoretical approaches to the treatment of elementary excitations in a non-Hermitian system can be resolved in experiments.
Quantum Gases (cond-mat.quant-gas)
Interlayer Registry Controls Polar Topology in Twisted Bilayer h-BN
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Twisting van der Waals bilayers creates a moir’e stacking field with periodically varying local interlayer registry, enabling spatially patterned polarization. However, a systematic understanding of how this registry-controlled polar topology evolves with twist angle, temperature, and mechanical strain is still lacking. Here, using first-principles-trained deep-potential molecular dynamics simulations, we show that spatially varying interlayer registry governs the polarization texture and can be directly tuned by twist and relative layer deformation. As the twist angle decreases, the moir’e polarization texture evolves from compact, nearly circular vortex-like patterns to extended triangular AB/BA domains. This crossover arises from enhanced lattice relaxation at small twist angles, which expands low-energy, oppositely polarized AB/BA regions and confines in-plane polarization mainly to domain boundaries. Despite this reconstruction, the local in-plane winding remains tied to interlayer registry and persists up to 1000 K, indicating robust topology against thermal fluctuations. We further show that the mechanical response is dictated by whether deformation changes the relative registry: homogeneous deformation of both layers produces only weak distortions, whereas layer-selective deformation strongly reconstructs the moiré polarization texture. A mismatch-matrix registry-mapping model is developed to capture this response, explaining deformation-induced changes in vortex radii at larger twist angles and triangular-domain geometry at smaller twist angles. These results identify interlayer registry as the central control parameter for forming and tuning moir’e polar topology in twisted bilayer h-BN.
Materials Science (cond-mat.mtrl-sci)
Real-space obstruction control of the shift current in two-dimensional Quantum Spin Hall insulators
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Michele Bagaglini, Mattia Iannetti, Jonas Erhardt, Jörg Schäfer, Ralph Claessen, Giorgio Sangiovanni, Gianni Profeta
The search for materials exhibiting a large bulk photovoltaic effect has recently expanded to low-band-gap systems capable of operating in the infrared regime, with potential applications in optoelectronics. Among the microscopic mechanisms contributing to this phenomenon, the shift current is one of the dominant sources of photocurrent generation. Owing to its geometric origin, the shift current is not only determined by the optical transition probability but also by the real-space displacement associated with the optical excitation, making non-centrosymmetric materials with obstructed electronic wave functions particularly promising candidates. In this work, using a tight-binding model of a quantum spin Hall insulator on a triangular lattice, we investigate the nonlinear photocurrent across trivial, quantum spin Hall, and higher-order topological insulating phases. We show that obstructed topological phases exhibit a substantially enhanced shift-current response, despite the similar electronic band structure. We identify the origin of this enhancement in optical transitions between states belonging to distinct Wannier-center sectors, which allow for a large real-space displacement upon photoexcitation and, depending on the topological phase, control the sign of the shift current. Our results extend the search for controllable bulk photovoltaic effects to materials characterized by real-space electronic obstruction and identify indenene, a monolayer of In on SiC(0001), as a promising candidate for realizing this phenomenon.
Materials Science (cond-mat.mtrl-sci)
Activity-Induced Structural and Dynamical Heterogeneity in Colloidal Gels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Santu Nath, Sudipta Mandal, Smarajit Karmakar
Active gels are intrinsically non-equilibrium materials whose structural and dynamical heterogeneity emerges from the interplay of attractive interactions, thermal fluctuations, and self-propulsion. We investigate a model active gel, simulated using large-scale Brownian dynamics simulations, to explore the effects of temperature $ T$ , active force strength $ f_0$ , persistence timescale $ \tau_p$ , and active particle concentration $ \rho_a$ . We characterize the structure of the evolving gel network through morphological analysis, while dynamical changes are quantified by the relaxation timescale and dynamical heterogeneity (DH). We show that an optimal choice of activity parameters yields a percolating gel network with faster gelation and larger voids and clusters, enhancing mechanical stability. Conversely, the structural relaxation timescale and DH decrease with increasing activity, indicating enhanced particle rearrangements and reduced spatial correlations of mobile and immobile regions. An effective temperature ($ T_\text{eff}$ ) framework for colloidal gels maps structural quantities and relaxation timescales in an active gel onto those of a passive gel. More interestingly, the growth of DH with increasing swim force can also be described by the same effective-temperature framework, in stark contrast to observations in active glasses. Our findings show that, in colloidal gels, temperature and active force compete, giving rise to similar structural ordering and, consequently, similar DH at the same $ T_\text{eff}$ . These findings highlight the crucial role of structural ordering in governing DH in active colloidal gels, as compared to active glasses.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
16 pages, 10 figures
Probing quantum nonlinear phononics in multilayer graphene with time-resolved Raman scattering
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Jakob Dolgner, Michael Rübhausen, Dirk Manske
Coherently driven phonons are conventionally described classically. Nonlinear phonon-phonon interactions, however, allow an infrared drive to reshape the fluctuation spectrum and generate substantial nonthermal enhancement of phonon fluctuations, motivating a description beyond the coherent displacement alone. We benchmark classical and semiclassical approximations against the full quantum theory and find that the semiclassical treatment substantially improves agreement with the quantum dynamics. We propose nonequilibrium spontaneous Raman scattering as a sensitive probe of these effects and apply our framework to recent experiments suggesting quantum nonlinear phononics involving the $ \mathrm{E}{1u}$ and $ \mathrm{E}{2g}$ modes in multilayer graphene. At very strong pump fields, driving the $ \mathrm{E}{1u}$ mode significantly modifies the $ \mathrm{E}{2g}$ Raman spectrum; however, reproducing the reported response at experimental field strengths requires accounting for pump-induced Raman matrix element dynamics or alternative energy pathways into the $ \mathrm{E}_{2g}$ mode. Our findings extend nonlinear phononics beyond average atomic displacements to the dynamics of lattice fluctuations, highlighting the interplay between coherent motion and quantum correlations in driven materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
22 pages, 10 figures
Tailored VxOy Metal–Insulator-Transition Oxides for Temperature-Triggered Smart Insulation in Superconducting Coils
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Mattia Ortino (GREEN), Davide Uglietti (SPC), Andrea Testino (PSI), Nicola Casati (PSI), Alexander Steppke (PSI), Wiktoria Wnetkowska (PSI), Andrea Masi (ENEA), Kamil Sedlak (SPC)
Smart insulation is a turn-to-turn layer that insulates in normal operation and conducts only near a hot spot. It could combine the fast ramping of insulated coils with the passive energy dump of non-insulated coils. Metal-insulator transition (MIT) oxides are natural candidates, but the only one tested in a coil so far, V2O3, switches at 150-170 K, far above the 30-70 K window useful for REBCO magnets. We explore the vanadium-oxygen system to lower the transition. TGA redox processing produced multi-phase powders with an effective transition near 127 K, about 25 K below V2O3. Hydrothermal V3O7, hydrated or annealed, was far too resistive and showed no usable transition. V2O3-epoxy specimens provided a robust reference and an acceptance criterion. Cryogenic measurements revealed a reproducible thermal hysteresis, and the measured specific heat of V2O3 corrects earlier model inputs by close to two orders of magnitude. A first electro-thermal model reproduces current sharing through the smart-insulation layer. Doped V2O3 and V8O15 are identified as the next targets.
Superconductivity (cond-mat.supr-con)
Submitted to Superconductor Science and Technology
Admittance extraction of quantum dot arrays for charge sensing
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Conor Power, Mathieu Moras, Andrii Sokolov, Robert Bogdan Staszewski, Elena Blokhina
This work demonstrates admittance extraction of quantum dot arrays using a rate equation frame- work matching experimental reflectometry measurements. Using a semiclassical rate equation, we consider a perturbation of the source/drain chemical potential to model reflectometry readout in a quantum dot array. This is a time-dependent extension of the rate equation which has been employed in literature for pumped arrays of quantum dots and capacitance extractions. Here we extend this to a double quantum dot for admittance extraction. The simulations are calibrated us- ing Fermi-Hubbard parameters extracted from experimental data, which it is then shown to closely approximate to.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Solubility of poorly soluble species in bulk and nanopores from grand-canonical Wang-Landau sampling
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Russell Kajouri, Adyant Agrawal, Philipp Stärk, Alexander Schlaich, Christian Holm
Poorly soluble species can have mean populations below one in small systems such as nanopores. In this regime, the grand-potential minimum, which identifies the most probable particle number, differs from the ensemble-averaged solute loading. We use grand-canonical Wang-Landau sampling (GCWLS) to calculate the density of states $ \Omega(N_\mathrm{A}, N_\mathrm{B})$ for a binary Lennard-Jones mixture of solute B in solvent A, both in bulk and in slit pores. One set of GCWLS simulations gives ensemble averages over a range of chemical potentials, whereas conventional grand-canonical Monte Carlo (GCMC) simulation requires a separate simulation at each state point. Independent GCMC simulations confirm the GCWLS ensemble averages. The solvent number distribution is nearly Gaussian, whereas the dilute solute distribution is skewed and Poisson-like. The most probable solute number therefore lies below the ensemble-averaged loading $ \langle N_\mathrm{B}\rangle$ and is zero whenever $ \langle N_\mathrm{B}\rangle<1$ . Reading the solute loading from the grand-potential minimum underestimates it and can falsely indicate that no solute is present. Defining the oversolubility as $ \mathcal{O}\mathrm{B}=x\mathrm{B}^{\mathrm{conf}}/x_\mathrm{B}^{\mathrm{bulk}}$ , where $ x_\mathrm{B}$ is the solute mole fraction, we find $ \mathcal{O}\mathrm{B}\approx12$ in a pore of 3.5 particle diameters width when both wall interactions are repulsive. Adding wall-solute attraction moderately raises it to $ \approx13$ , whereas wall-solvent attraction lowers it to $ \approx3.4$ . This comparison shows that the wall-solvent interaction controls most of the enhancement. As the pore widens, $ \mathcal{O}\mathrm{B}$ decreases toward unity. In bulk and in nanopores alike, the solubility of poorly soluble species should be obtained from ensemble averages rather than from grand-potential minima.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Nontrivial topological properties from the cooperation of static perturbations and Floquet fields in type-II semi-Dirac semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
In this work, we present a comprehensive theoretical study for the topological and anomalous transport properties of type-II SDSMs under three scenarios, i.e., static symmetry-breaking perturbations, periodic Floquet driving by two-frequency orthogonally polarized light (TFOPL), and their cooperative effects in the hybrid scenario. We first show that a static mass $ m_z$ opens a bulk gap and drives the system into a Chern insulator with Chern number $ C^{\rm per}=\pm 2,{\rm sgn}(m_z)$ . In comparison, TFOPL alone only shifts the positions of Dirac points and cannot open a full gap. Nevertheless, it produces a Berry curvature odd in the $ x$ -direction, yielding a finite Berry curvature dipole (BCD) along $ x$ proportional to the sine of the initial phase, while the $ y$ -component vanishes. The hybrid scenario, by contrast, exhibits a remarkably rich phenomenology. Specifically, its gap-closure criterion becomes cubic and thus admits up to three real roots when the effective parameter along the $ x$ -direction is negative, thereby producing multiple light-tunable gap-closing points and a series of topological phase transitions. In particular, the BCD exhibits a double-peak structure with strong enhancement near gap-closing manifolds and synchronized sign reversal of the full vector under external tuning. We further analyze the anomalous Hall conductivity (AHC), anomalous Nernst conductivity (ANC), and anomalous thermal Hall conductivity (ATHC). The AHC and ATHC exhibit quantized plateaus that serve as signatures of Chern-insulator phases, while the ANC, being a Fermi-surface probe, provides complementary local information and can identify light-induced gaps even when global topological invariants remain unchanged. Taken together, these results offer useful insights into the topological properties of 2D type-II SDSMs and related systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
21 pages, 11 figures
Topological Chiral Superconductivity from Doping Correlated Charge Transfer Insulator with Orbital Magnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Wen Sun, Yuan Yang, Shou-Shu Gong, Wen Huang
Topological chiral superconductivity has been extensively studied from the perspective of electronic structures in momentum space, while its emergence from real-space processes in strongly interacting systems remains largely unexplored. Here, we study a doped charge-transfer insulator in a strongly repulsive spinless-fermion model with three sublattices and $ 2\pi$ flux per unit cell. Combining perturbative analysis, exact diagonalization, and density matrix renormalization group simulations, we establish a topological superconducting ground state with $ p+ip$ symmetry. In the large charge-transfer gap limit, chiral charge-transfer excitations generate a correlated-hopping process that provides a microscopic mechanism for electron pairing and its chiral structure. The chiral superconductivity persists into the smaller-gap regime, where chiral excitonic two-particle bound state can emerge. Our results establish a concrete real-space route to topological chiral superconductivity upon doping strongly interacting charge-transfer insulators with orbital magnetism.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
26 pages, 12 figures
Confinement-deconfinement transitions in the dimer-loop models on two-dimensional non-bipartite lattices
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Jay Pandey, Souvik Kundu, Kedar Damle
Recent work [Kundu, Damle, Phys. Rev. X 15, 011018 (2025)] has demonstrated that a class of $ S=1$ kagome lattice antiferromagnets with competing anisotropies can exhibit unusual low-temperature behavior that is best described in terms of the statistical mechanics of an interesting interpolation between the fully-packed dimer model and the fully-packed loop model on the bipartite honeycomb lattice. On this and other bipartite lattices in two and three dimension, such fully-packed dimer-loop models generically have two distinct power-law correlated Coulomb phases, both of which admit a low-energy description in terms of a fluctuating divergence-free polarization vector field [Phys. Rev. X 15, 011018 (2025); arXiv:2510.11607]. The transition between these phases corresponds to a confinement transition for the $ Z_2$ part of the corresponding $ U(1)$ flux [Phys. Rev. X 15, 011018 (2025); arXiv:2510.11607]. Here we demonstrate that a variant of such a topological confinement transition can also exist in dimer-loop models on non-bipartite lattices such as the kagome and triangular lattices although the low-energy description does not feature any conserved $ U(1)$ flux. In these non-bipartite dimer-loop models, both phases are short-range correlated liquids, and the topological distinction between them is in terms of a $ Z_2$ -valued winding number instead of the flux of a divergence-free polarization field. In spite of this key difference, this transition appears to be in the same Ising universality class as the analogous transition of the bipartite dimer-loop models. These kagome and triangular lattice dimer-loop models correspond respectively to the low-energy limit of a class of $ S=1$ antiferromagnets with competing anisotropies on the ruby lattice comprising a corner-sharing arrangement of fully-frustrated squares and a lattice of corner-sharing fully-frustrated hexagons.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 16 figures
Domain-wall-to-domain interconversion in a polar conducting oxide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Martin F. Sarott, Majid Ahmadi, Johanna van Gent González, Ewout van der Veer, Mads C. Weber, Jacopo Pinna, Daniel A. Chaney, Arijit Sinha, Hamideh Hassani, Horatio R. J. Cox, Thomas Perrault, Amir Sabet Ghorabaei, Maria A. Loi, Philippe Ghosez, Bart J. Kooi, Beatriz Noheda
Domain walls in ferroic crystals are topological defects with a symmetry distinct from the domain interior, allowing them to display functionalities that are otherwise forbidden in the host material. Despite their unique properties, domain walls are strictly confined to two-dimensional interfaces, which hinders unveiling their true nature and limits their applicability. Here, we demonstrate reversible dimensionality control by expanding nanoscale domain walls into three-dimensional functional regions in polar epitaxial tungsten trioxide ($ \text{WO}_3$ ). This domain-wall-to-domain interconversion is enabled by the conducting, non-polar domain walls adopting the parent-phase structure. An alternating electric field applied through a scanning probe tip induces localized heating, which expands this domain-wall phase into the adjacent polar domains. This approach enables reversible spatial control to switch between mutually exclusive properties of domains (polarity) and domain walls (conductivity), offering a new paradigm for reconfigurable oxide electronics.
Materials Science (cond-mat.mtrl-sci)
Destructive Interference of a Charge Density Wave in the Skyrmion Magnet GdRu2Si2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
G. D. A. Wood, D. A. Mayoh, F. Orlandi, A. Bombardi, D. D. Khalyavin, P. Manuel, S. H. Moody, P. D. Hatton, R. D. Johnson, T. W. Chamberlain, O. A. Petrenko, M. R. Lees, G. Balakrishnan
In skyrmion magnets, charge density waves induce higher-order exchange interactions that can select multi-Q ground states. Using resonant X-ray scattering and neutron diffraction, we measure temperature-dependent spin-charge coupling in GdRu2Si2. A minimal Landau model with one critical exponent and two ordering temperatures reproduces all six observed order parameters. Spin-density wave components of the multi-Q ground state drive charge ordering, but the onset of a magnetic helix suppresses it via destructive interference.
Strongly Correlated Electrons (cond-mat.str-el)
Colloid-Colloid Interactions Impact Network Morphology of Confined Colloidal Drying Patterns
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Andreas Andersen Hennig, Natalia Kizilova, Ilaria Beechey-Newman, Erika Eiser
Colloidal suspensions that are confined between two closely spaced plates and left to evaporate slowly form maze-like labyrinth patterns in the final stage of evaporation. The fingers in these patterns form bifurcations and occasionally loops, which we may quantify with a skeletonization method. We compare drying patterns formed with two different salt concentrations in the droplet which changes the screening length and therefore the effective colloid interactions. We find that the junctions generally follow Murray’s law for optimal transport networks, and that the typical bifurcation angles peak around 53. Screened droplets additionally show more loopy networks, and is characterized by bands of transversal fingers before merging into a central non-fingering colloidal aggregate. Our observations suggest that colloid-colloid interactions can strongly influence the large-scale topology of the pattern while leaving the local geometry of the individual fingers unchanged.
Soft Condensed Matter (cond-mat.soft)
16 pages, 10 figures, 1 table. Submitted to the Journal of Chemical Physics
1/f frequency-noise reduction in nanomechanical resonators by dissipation dilution
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Kostas Kanellopulos, Silvan Schmid
The frequency noise of a resonant nanomechanical sensor is well understood down to its thermomechanical limit, but the longest useful averaging time is set by a flicker, or $ 1/f$ , frequency-noise floor whose origin has remained unknown. We show that this floor is the thermal noise of the tension. By the fluctuation-dissipation theorem, the tension of a resonator with fixed ends fluctuates by an amount set by the loss angle of its material; for structural damping, these fluctuations produce $ 1/f$ frequency noise with a flicker coefficient $ h_{-1}=E k_{\mathrm{B}} T/(2\pi V\sigma_0^2 Q_{\mathrm{el}})$ , with $ Q_{\mathrm{el}}$ the intrinsic loss under elongation, that contains no free parameter and is diluted by the tensile stress $ \sigma_0$ in the same way as damping is in dissipation dilution. Silicon nitride strings and membranes from 30 to 340nm thickness follow the predicted volume scaling, the predicted $ \sigma_0^{-2}$ dilution across resonators and within stress-engineered strings, and the predicted thickness dependence, which places noise-active two-level systems in the volume and at the surfaces of the resonators, all at the absolute level set by the independently measured intrinsic loss. The same relation accounts for published data between 78 and 296K; below 78~K, the loss measured at the resonance no longer represents the loss probed by the noise, marking the limit of the structural-damping assumption. Dissipation dilution therefore lowers the $ 1/f$ floor, and the longest useful integration time of a resonant sensor is set by its prestress, volume, temperature, and intrinsic loss angle.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Instrumentation and Detectors (physics.ins-det)
11 pages, 6 figures; Supporting information: 7 pages, 3 figures
Emergent Spinorial Structure in Mesoscopic Irreversible Thermodynamics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
We reconstruct a geometry of thermodynamic coordinates from transport coefficients within a mesoscopic canonical model. Self-adjoint flux observables determine a compatible evolution generator containing symmetric and antisymmetric transport coefficients. When the Hermitian transport tensor is positive, an exact graded first-order factorization reproduces this generator on its scalar sector. Its commutators define a spectral distance whose metric depends only on the symmetric tensor. Gradients of the antisymmetric tensor can change the evolution while leaving the metric unchanged. The construction allows coordinate-dependent coefficients. In the constant Onsager regime, a Clifford representation gives the same distance and an algebra fixed by the transport matrix. Published transport data for a $ \mathrm{Bi_2Te_3}$ film give a principal-distance ratio of approximately $ 2.12$ in normalized coordinates at $ ZT\simeq0.68$ . We also examine a separate quadratic entropy-production observable and distinguish its discrete spectrum from the spectrum of the evolution generator. The spinorial representation adds no physical spin degrees of freedom.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 1 figure
Impact of shear and dilational membrane viscosities on capsule shape and dynamics under shear flow: a theoretical study
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
In artificial (micro)capsules or cells such as red blood cells for example, the two-dimensional (2D) rheology of the membrane (or the shell) is viscoelastic and not only elastic. The deformation and inclination of such a capsule are theoretically studied under shear and extensional flows. The membrane mechanics is described by the Kelvin-Voigt model: the 2D dissipation with the Boussinesq-Scriven law associated to specific dilational and shear Boussinesq numbers $ Bq_d$ and $ Bq_d$ respectively while the elastic constitutive law is either Hookean, strain-softening (neoHookean) or strain-hardening (Skalak). The dynamics depends on the elastic capillary number $ Ca$ , the Poisson ratio (or $ C$ in Skalak law), the viscosity ratio $ \lambda$ , the nonlinearities included in the constitutive law and both boussinesq numbers. Three dynamics are identified in the limit of weak deformations: a tank-treading motion in the limit of small elastic capillary number with a characteristic time depending on $ \lambda$ , $ Bq_s$ and $ Bq_d$ , an oscillation without any elasticity and a damped oscillation leading to a tank-treading motion in the limit of large Boussinesq numbers. In all cases, both shear and dilational 2D dissipations contribute differently leading to non-trivial results. In the case of a Skalak law with $ C=1$ , $ Bq=Bq_s=Bq_d$ and $ Bq>>\lambda$ , the deformations in the limits $ Ca<<1$ , $ Bq=O(1)$ and $ Ca=O(1)$ , $ Bq>>1$ determined in the seminal work of \cite{barthes1985role} are recovered.
Soft Condensed Matter (cond-mat.soft)
Transport Determines Spectral Distance in Mesoscopic Thermodynamics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
We derive a distance between thermodynamic states from a positive Hermitian transport tensor within a mesoscopic canonical model. An exact first-order factorization of the evolution generator gives a commutator norm and the metric $ G=2g^{-1}$ , where $ g$ denotes the symmetric transport tensor. Gradients of the antisymmetric tensor can change the evolution, but they leave this distance unchanged. The construction allows coordinate-dependent coefficients. For constant Onsager coefficients, a Clifford representation gives the same metric. In a two-channel thermoelectric system, the ratio of normalized principal distances is $ \sqrt{1+ZT}+\sqrt{ZT}$ . Transport coupling thus fixes the anisotropy of this metric. The construction requires neither an independent metric nor a physical spin variable.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
3 pages
Engineering Ferroelectric Phases in BaTiO$_3$ Films via Buffer-Layer Induced Misfit Strain Reversal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
A.S. Mikheykin (1), N.V. Lyanguzov (1), A.S. Konstantinov (1), V.B. Shirokov (1 and 2), E.D. Linnik (1), T. Bondar (1), A.G. Razumnaya (3) ((1) Southern Federal University, (2) Federal Research Centre The Southern Scientific Centre of the Russian Academy of Sciences (3) Jožef Stefan Institute)
Controlling ferroelectric phase symmetry through strain engineering is crucial for tailoring polarization topology and functional properties in oxide-based devices. Here, we show that a thin conductive buffer layer can override substrate-induced strain in BaTiO$ _3$ (BTO) films on MgO. Although the lattice parameter of MgO(001) would be expected to induce tensile misfit strain, in 500~nm BaTiO$ _3$ films the thermal-expansion mismatch dominates, resulting in effective compressive stress upon cooling. Inserting a 50-nm La$ _{0.67}$ Sr$ _{0.33}$ MnO$ _3$ (LSMO) buffer layer reverses the effective strain state from compressive to tensile. Using temperature-dependent polarized Raman spectroscopy, X-ray diffraction, and piezoresponse force microscopy, we reveal an unconventional phase sequence upon cooling: paraelectric $ \rightarrow$ orthorhombic ($ \textit{aa}$ -phase, $ \sim$ 407 K) $ \rightarrow$ monoclinic ($ \textit{r}$ -phase, $ \sim$ 300-345 K), characterized in-plane and tilted polarization components. The LSMO layer not only serves as a bottom electrode but also modifies the strain state, while interfacial charge redistribution induces a built-in electric field, evidenced by self-polarization and asymmetric PFM hysteresis. These findings highlight the critical role of conductive buffer layers in controlling ferroelectric symmetry and enabling oxide heterostructures with tailored polarization textures for low-power spintronics, tunable microwave devices, and neuromorphic computing.
Materials Science (cond-mat.mtrl-sci)
1 graphical abstract, 10 figures, 26 pages
Quantum Ising transition on the Cayley tree: boundary criticality, universality, and an effective Bethe line
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Pietro Richelli, Natalia Chepiga
We investigate quantum criticality in the transverse-field Ising model on finite Cayley trees and demonstrate that their extensive boundary fundamentally changes the nature of the quantum phase transition compared with the infinite, boundary-free Bethe lattice. Using tree tensor-network simulations for systems with up to $ N=12286$ sites, we identify a boundary-driven continuous transition at $ h_x^c\approx1.76$ , distinct from the mean-field Bethe-lattice transition at $ h_x^c\approx2.23$ . We characterize this transition through finite-size scaling of the magnetization and magnetic susceptibility and extract a consistent set of critical exponents. By introducing next-nearest-neighbor interactions, we demonstrate the robustness of the extracted critical exponents, providing numerical argument for the Ising boundary universality class on the Cayley tree. Furthermore, we show that the physics of the boundary-free Bethe lattice can be efficiently recovered on a finite Cayley tree by fine-tuning a local boundary field. The resulting \textit{effective Bethe line}, whose existence is tied to the mean-field nature of the bulk transition, effectively screens the extensive boundary and restores both the critical point and the mean-field critical scaling of the infinite Bethe lattice.
Strongly Correlated Electrons (cond-mat.str-el)
31 pages, 27 figures
Information Entropy as a Sensitive Diagnostic of Relaxation Dynamics in a Quasiperiodic Mott Insulator
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-14 20:00 EDT
N. D. Chavda, Antônio M. S. Macêdo, Robin P Sagar, Barnali Chakrabarti
We study the nonequilibrium dynamics of a bosonic Mott insulator following a sudden quench from a periodic to a quasiperiodic lattice. Using ab initio multiconfigurational (MCTDHB) continuum many-body dynamics, we characterize the evolution through momentum distributions, fragmenta- tion, correlation functions, and information entropy. We find that melting of Mott correlations does not necessarily imply relaxation of the many-body state. In the weakly interacting regime, the initial Mott-like correlation undergo recurrent melting and partial recovery, while the information entropy displays large, intermittent fluctuations within the simulated time window. In contrast, a strongly interacting and fully fragmented Mott insulator retains its characteristic Mott correla- tions, up to partial distortions, while the many-body information entropy approaches a well-defined stationary regime plateau with comparatively small fluctuations. These results indicate that Mott- correlation dynamics and many-body relaxation can be dissociated in this finite system and support the use of information entropy, evaluated in the multiconfigurational representation, as a sensitive complementary diagnostic of nonequilibrium relaxation.
Quantum Gases (cond-mat.quant-gas)
Self-phoresis on a one-dimensional periodic domain
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
We study the spontaneous motion and collective dynamics of self-phoretic particles on a one-dimensional periodic domain. The particles act as localized chemical sources (of a particle-dependent strength) of a field and the particles themselves respond to the gradients of the field they generate (with a particle-dependent phoretic mobility). The chemical field itself diffuses and evaporates. For a single particle, we derive the exact threshold for spontaneous propulsion and establish the emergence of stable constant-velocity states near onset through a supercritical pitchfork bifurcation. We then consider an active source coupled to a non-emitting tracer and determine the conditions for slipping and stable phase-locked motion. For two mutually coupled sources, the stationary antipodal configuration can lose stability through either a pitchfork or a Hopf bifurcation, depending on the relative source strengths and phoretic mobilities. We determine the competing instability thresholds and compare them with direct numerical simulations of the coupled particle-field equations. Beyond onset, the resulting translating and oscillatory states provide qualitative counterparts to modes of motion observed experimentally for camphor disks in annular water channels. These results connect the onset of individual propulsion, tracer entrainment, and collective motion within a common analytically tractable framework.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
56 pages
Molecular Precursor Chemistry Shapes Early-Stage Reaction Pathways in Nitrogen-Doped Carbon Nanotube Synthesis
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Narayan N. Som, Lukasz Nowicki, Tomasz Gizewski, Karolina Z. Milowska, Anna Wroblewska, Caghan Tuncer, Maciej Trzaskowski, Olga Iwasinska-Kowalska, Tomasz Plocinski, Mariusz Zdrojek, Krzysztof K. Koziol, Malgorzata Jakubowska, Agnieszka Lekawa-Raus
The structural characteristics of carbon nanotubes are usually discussed in terms of processes occurring during nanotube nucleation and subsequent growth from an already formed catalyst nanoparticle. Here, we show that their structural trajectory can begin much earlier, within the first nanoseconds of precursor decomposition and catalyst formation. We combine experiment and reactive molecular dynamics to compare nitrogen-free CNT synthesis with two closely related aromatic nitrogen precursors, pyridine and pyrazine, containing one and two nitrogen atoms per molecule, respectively. Experimentally, both nitrogen-containing precursors promote bamboo-like CNT formation and produce substantially more structurally disordered CNTs than the nitrogen-free reference. Notably, nitrogen incorporation does not scale simply with the amount of nitrogen supplied, demonstrating a strong contribution from precursor chemistry. Reactive molecular dynamics reveals that nitrogen-containing precursors significantly modify local Fe-carbon and Fe-SiO2 interactions during catalyst evolution, while pyridine and pyrazine exhibit distinct decomposition pathways, with pyrazine showing significantly greater decomposition within the simulated timescale. These results demonstrate that precursor chemistry influences the local chemical environment and early catalyst evolution, highlighting its potential role in the initial stages of CNT growth.
Materials Science (cond-mat.mtrl-sci)
Trust-Limited Machine-Learning-Accelerated Nudged Elastic Band Calculations for Small-Polaron Hopping in Rutile TiO2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Ashish Kumar Singh, Irina V. Lebedeva
Nudged elastic band (NEB) calculations of small-polaron hopping are demanding because nuclear motion is coupled to a self-consistent localized electronic state. Near the charge-transfer region, slow self-consistent-field convergence, localization switching, and competing electronic solutions complicate surrogate-assisted optimization. We develop a Gaussian-process-assisted NEB workflow for this regime and demonstrate electron small-polaron hopping in rutile TiO2 using spin-polarized density functional theory with a Hubbard U correction (DFT+U ) with SIESTA. A joint energy-force Gaussian process (GP) with a Matérn covariance model advances the elastic band, while active-atom root-mean-square and maximum-atom displacement limits constrain surrogate motion relative to evaluated configurations. Reaching these limits triggers first-principles sampling without requiring full surrogate convergence. Three independently DFT-verified 96-atom [001] calculations using 11, 13, and 15 images and different surrogate settings and GP parameterizations yield barriers of 0.1645, 0.1637, and 0.1640 eV, respectively, spanning 0.793 meV. In the 15-image calculation, repeated central-image sampling activates a separately calibrated local GP during surrogate optimization. Final full-band DFT verification gives a maximum projected NEB force of 0.0346 eV/Å. A 324-atom calculation yields a lower barrier of 0.1302 eV, indicating supercell sensitivity and demonstrating feasibility at larger GP observation dimension. The workflow combines controlled surrogate extrapolation, targeted charge-transfer-region interpolation, and independent DFT verification to obtain polaron migration pathways, emphasizing reproducible barriers and full-band force convergence.
Materials Science (cond-mat.mtrl-sci)
Magnetic properties and excitation spectrum of the S = 1/2 three-legged spin ladder, LiMoOP2O7
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Aly H Abdeldaim, Alexander A. Tsirlin, Jacques Ollivier, Clemens Ritter, Robin S. Perry, Lucy Clark, Gøran J. Nilsen
We report a comprehensive experimental study including density functional theory calculations detailing the magnetic ground state of the $ S = 1/2$ Mo$ ^{5+}$ pyrophosphate, LiMoOP2O7, and its magnetic excitations. Neutron powder diffraction measurements confirm the $ P2_1/n$ structural model which is comprised of a three-legged ladder of distorted Mo$ ^{5+}$ octahedra. Magnetometry and specific heat reveal a long-range magnetic ordering transition at $ T_\textrm{N} = 3.5$ ~K and a field-induced transition at $ \mu_{0}$ H$ _\textrm{c}$ = 1 T. This zero-field long-range magnetic order was determined to be a commensurate $ \kappa = 0$ order with an ordered moment that is reduced from the full $ S = 1/2$ magnetic moment by 30%. Through inelastic neutron scattering measurements and density functional theory calculations, we define the minimal microscopic model and resolve the spin Hamiltonian up to the seventh leading exchange parameter, resulting in a model with dominant antiferromagnetic leg interactions, weaker ferromagnetic rung interactions, and a significant interlayer ferromagnetic coupling.
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 9 figures
Mutual linearity from classical response theory
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Timur Aslyamov, Massimiliano Esposito
We unify known mutual-linearity relations for Markov jump processes and chemical reaction networks within a common framework based on classical finite-response theory. In a Markov jump process, an exact finite-response identity shows that all stationary probability changes share a common factor when the rates of one edge change. Eliminating this factor gives the relations between probabilities, observables, and currents, even far from equilibrium. We also explain how the same argument applies when one coefficient of a linear system changes and recovers the known relations in Laplace space and between stationary complex activities in chemical reaction networks.
Statistical Mechanics (cond-mat.stat-mech)
Mutual information across the commensurate–incommensurate crossover and near the Kosterlitz–Thouless point of the spin-$\tfrac12$ $J_1$–$J_2$ Heisenberg chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Wuttichai Pankeaw, Pruet Kalasuwan
What quantum mutual information adds to conventional correlation functions is often unclear. We study the spin-1/2 $ J_1$ -$ J_2$ Heisenberg chain, using DMRG on infinite chains and periodic rings and an SU(2) decomposition of the mutual information into correlation channels. For singlet ground states the two-site mutual information is an exact function of the spin correlator, so any additional content must come from blocks. In the dimerized phase, blocks resolve bond-energy correlations in the SU(2)-scalar channel without an independent asymptotic length: singlet and triplet correlation lengths agree to about 1%. The scalar channel dominates block mutual information at large distances in the commensurate regime up to $ J_2/J_1=0.40$ , but falls to a few percent beyond the disorder point, which coincides numerically with the Majumdar-Ghosh point $ J_2/J_1=1/2$ ; the structure-factor peak splits only at the Lifshitz point $ J_2/J_1=0.520622(2)$ . On the gapless side we compare block mutual information on rings extrapolated to infinite size with the two-interval prediction of SU(2)$ _1$ conformal field theory across the Kosterlitz-Thouless point $ J_2/J_1=0.241167$ . There, for block lengths $ l\le6$ , the correction decays as $ l^{-p}$ with $ p=1.96$ -$ 2.07$ , and any logarithmic term is at least 60 times smaller than in the Heisenberg chain. Expanding in the marginal coupling (from level spectroscopy) the first-order coefficient is consistent with $ l^{-2}$ scaling and the second-order coefficient is positive for $ x\le1/4$ , suggesting that the mutual information relative to the field-theory value becomes stationary at the KT point for large blocks. The scalar-channel share approaches 1/4 at small cross ratio $ x$ , as expected from SO(4) symmetry; under two stated assumptions its first-order response to the coupling is $ (3/8)\ln x-5/8$ at small $ x$ , matched by the $ l=4$ data within 1-3% at $ x\le1/9$ .
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
57 pages, 19 figures, 16 tables
Microscopic Modeling of Interlayer Tunneling in Twisted Bilayer Cuprates
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Siddhant Panda, Andreas Kreisel, Laura Fanfarillo, P. J. Hirschfeld
The field of twistronics, recently extended to twisted bilayer cuprate systems, has generated considerable interest due to the prediction of $ d+id’$ states close to a $ 45^\circ$ twist, as suggested by multiple experimental probes. Theoretical studies of these systems using a variety of models and many-body theoretical techniques have revealed multiple competing order parameters. The large variability in experimental results and theoretical predictions demands an accurate microscopic model for these systems, in particular a more realistic description of the interlayer tunneling. In this study, we fit the in-plane hopping and compute the interlayer tunneling amplitudes by calculating the orbital overlap between $ d_{x^2-y^2}$ wave functions at each site of the twisted square-lattice model. We observe sign-changing tunneling amplitudes, a strong twist-angle dependence of the direct tunneling term, and long-range tunneling amplitudes that often dominate over direct tunneling. We investigate the band structure, Fermi surfaces, and spectral functions in comparison with those obtained from the phenomenological model and find a substantial redistribution of spectral weight that modifies the competition between different superconducting ground states. We determine the phase diagram as a function of twist angle, filling, and direct tunneling strength, which is controlled by the $ c$ -axis distance between the monolayers, and observe a reduction in the region of time-reversal-symmetry-breaking (TRSB) $ d+id’$ states compared with the phenomenological model. Finally, we investigate the Josephson critical current across the phase diagram and find strongly suppressed critical currents close to a $ 45^\circ$ twist, consistent with experimental observations.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 11 figures
First-fracture kinetics in periodic chains: from free-energy landscapes and dynamical recrossing to absolute rates
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
The nearly collinear configuration of highly stretched polymer chains before fracture motivates one-dimensional models. At fixed extension, stretching one bond redistributes length among the others, coupling rupture to the whole chain. In this work, I develop a framework for fracture-healing rates in periodic Morse chains, combining deterministic theories, equilibrium simulations and a quasi-deterministic approach using equilibrium fluxes and barrier-top trajectories. Constrained-partition calculations closely reproduce simulated populations and intact-state tensions. An intact-reservoir potential of mean force (PMF) supplies the first-fracture surface probability, while recrossing corrects the attempt flux without a rate-fitted prefactor. Independent rate tests identify an operational chain-length boundary for accurate two-state kinetics; failed-return durations decrease relative to population relaxation as chains grow. Kramers-Grote-Hynes (KGH), nonlinear reactive-flux and equilibrium rates show excellent agreement in this regime. KGH predicts rates away from coexistence and a chain-dependent local activation length dominated by the barrier response. Rates decrease approximately exponentially before declining more gently for longer chains: barrier growth dominates, additional fracture sites partly compensate, and transmission varies more weakly. Beyond coexistence, long chains can fracture practically irreversibly because healing becomes too rare to observe. Projected committor crossings, where the configuration-averaged probability of reaching the fractured core first is one half, lie near site-PMF maxima, although configurations at equal bond length retain different fracture probabilities. Multiple fractures remain negligible near coexistence through at least $ N=50$ . The framework could supply state-dependent rates to mesoscopic fracture models of polymer networks.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
18-page article with 12 figures and supplementary information. Code and supporting data: this https URL
First-Principles Calculations of the Electron-Hole-Pair Creation Energy in Semiconductors and Dielectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Dallin O. Nielsen, Massimo V. Fischetti
We present first-principles calculations of the electron-hole-pair creation energy in semiconductors and dielectrics, focusing in particular on AlN, 3C-SiC, 4H-SiC, Si, and SiO2. We have employed density functional theory (DFT) to calculate the band structure, density-functional perturbation theory to obtain the phonon dispersion, and time-dependent DFT (TDDFT) to calculate the electron energy loss function (via the dielectric function). We performed full-band Monte Carlo simulations of electron thermalization for energies up to ~100 eV and calculated the average energy required to excite an electron-hole pair. We calculated pair-creation energies of approximately 12.2, 6.5, 7.3, 3.10, and 16.7 eV/pair for AlN, 3C-SiC, 4H-SiC, Si, and SiO2, respectively. These values are in good agreement with measured data, with the largest discrepancy being that of Si (about 14.9% lower than the accepted experimental value of ~3.6 eV/pair). To improve the agreement for Si, we used the GW approach and the Bethe-Salpeter equation (BSE) to calculate the quasiparticle shifts of the electronic band structure and the dielectric function, respectively. Finally, using the GW/BSE data, we calculated a creation energy of ~3.50 eV/pair. We find that the marked improvement in the accuracy of the calculated creation energy, when using the GW/BSE approach, is primarily attributable to the slight decrease in the magnitude of the electron energy-loss function when using the GW/BSE approach for energies below ~10-15 eV. Overall, it is clear that the competition between phonon emission and ionization near the intersection of the phonon scattering and ionization rates is largely responsible for determining the value of the creation energy, with the other major factor being the location and shape of the plasmon peak in the energy-loss function.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
14 pages, 14 figures
Emergent low-energy thermodynamics and universal $B/T$ scaling in $α$-RuCl$_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
A. Khansili, B. J. Ramshaw, A. Bangura, H.-Y. Kee, R. D. McDonald, F. Assaad, A. Rydh, A. Shekhter, K. A. Modic
Quantum spin liquids are exotic states of matter in which strongly interacting spins remain disordered down to zero temperature and host fractionalized excitations. This has motivated an extensive search for their realization in materials. Among candidate systems, $ \alpha$ -RuCl$ _3$ has drawn particular attention as a platform for the quantum spin liquid proposed by Kitaev, in which the low-energy excitations in applied magnetic fields are interpreted as itinerant Majorana fermions and local flux excitations. However, conflicting experimental signatures have cast doubt on whether a Kitaev quantum spin liquid-like state is really the right starting point to interpret the low-energy states in $ \alpha$ -RuCl$ _3$ , motivating a closer look at the nature of these excitations. Here we report an extensive high field study of specific heat up to 35 T on $ \alpha$ -RuCl$ _3$ . We find that the low-energy thermodynamics exhibit universal $ B/T$ scaling with a single effective energy scale proportional to the applied field as long as the magnetic field is not close to the $ c$ -axis. This behavior persists continuously from the antiferromagnetic phase boundary to the highest fields, suggesting that the perturbative Kitaev limit, with its Majorana and flux excitations, may not be an appropriate starting point for describing the low-energy thermodynamics of $ \alpha$ -RuCl$ _3$ for fields away from the $ c$ -axis.
Strongly Correlated Electrons (cond-mat.str-el)
5 figures
High-Efficiency Field-Free Superconducting Diodes in Mo$_2$N/FePt Bilayers
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Juan S. Cruz, Emilio De Biasi, Juan C. Zapata, Yeonkyu Lee, Jeehoon Kim, Nestor Haberkorn
Near-ideal, field-free superconducting diode behavior is demonstrated in room-temperature-grown Mo$ _2$ N/FePt bilayers. The response is consistent with remanent FePt stripe domains producing polarity-dependent thresholds for flux entry and vortex motion. Micromagnetic simulations reveal a periodic stray-field modulation across the stripes and asymmetric field enhancement near their ends at the bridge edges. One current polarity remains nearly dissipationless up to a sizable fraction of the estimated depairing current, whereas the opposite polarity develops dissipation at much lower current, yielding diode efficiencies up to approximately 85% in the thinner bilayer. The nonreciprocity can be continuously tuned by the in-plane magnetic preparation angle and reversibly switched by reverse-field excursions through the hysteretic reversal of the FePt layer. These results support edge-controlled flux entry and vortex motion as a route to high-efficiency superconducting diodes.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
25 pages, 5 main figures, 2 supplementary figures, and 1 supplementary table. Supporting Information included
Microscopic Theory of the Acoustic Faraday Effect in Spin-Orbit Coupled Magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Antoine Matar, Haoting Xu, Hae-Young Kee
The acoustic Faraday effect probes phonon Hall viscosity through the rotation of transverse acoustic polarization, conventionally interpreted in terms of circular birefringence. We show that magnetic order breaking rotational symmetry generates anisotropic phonon responses and elliptically polarized eigenmodes, so that Faraday rotation cannot be attributed to Hall viscosity alone. To elucidate their microscopic origin and consequences, we derive spin-phonon couplings from a generic $ J$ -$ K$ -$ \Gamma$ -$ \Gamma’$ model with interlayer coupling, identifying transverse strain couplings for propagation along the $ c$ -axis arising from the interplay of Kitaev $ (K)$ and $ \Gamma$ interactions, along with strain-induced $ g$ -tensor contributions. Incorporating these couplings into our theory for the Kitaev spin-liquid candidate $ \alpha$ -RuCl$ _3$ , we find that symmetry breaking modifies the Faraday response, revealing a Hall viscosity approximately twice the value inferred assuming rotational symmetry. Our results establish a microscopic framework beyond circular birefringence, refining the connection between acoustic Faraday rotation and phonon Hall viscosity in symmetry-broken spin-orbit-coupled magnets.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 3 figures
Honeycomb Crystal in a Mass-Asymmetric Electron-Hole Bilayer
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Shengdu Chai, Wangqian Miao, Yuqiang Li, Lei Wang, Xi Dai, X.C. Xie
A two-dimensional electron gas in a uniform neutralizing background forms a triangular Wigner crystal at low density. In a strongly mass-asymmetric electron-hole bilayer, localized heavy holes instead provide a nonuniform positive background that supports an electron crystal at densities two orders of magnitude higher than for a homogeneous electron gas in the same material. Here we show that correlated mobile electrons can overturn the preference for triangular order, stabilizing a honeycomb electron-hole crystal. Using the powerful real-space neural-network variational Monte Carlo in the Born-Oppenheimer limit with fixed holes, we find that increasing the density drives a transition from a triangular electron-hole crystal to a honeycomb crystal, which eventually melts into itinerant electrons coexisting with the honeycomb or the triangular hole lattice at fixed interlayer separation. Relative to triangular order, honeycomb order emerges when gains in electronic kinetic energy and electron-hole attraction outweigh its higher intralayer Coulomb repulsion, a threshold never reached in the rigid point-dipole model. Moreover, the honeycomb hole lattice supports paramagnetic, antiferromagnetic, and stripe-ordered spin states. Complex polarization indicates a metal-insulator transition, while the states on the honeycomb hole lattice are consistent with a stripe-ordered Dirac semimetal and paramagnetic or antiferromagnetic Mott insulators via mapping to the half-filled Hubbard model. We further propose a BLG/hBN/WS$ _2$ -WSe$ _2$ heterostructure as a platform for the predicted honeycomb crystal, at an experimentally feasible density $ n\sim10^{11}~\text{cm}^{-2}$ .
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG), Computational Physics (physics.comp-ph)
Bifurcation Structure of Double Hysteresis and Isolated Branches in a Parametric Duffing Nanoresonator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Dingda Zhang, Maria Kallergi, Chanyoung So, Eva M. Weig, Ahmed A. Barakat
Direct and parametric driving together generate nonlinear response structures beyond conventional Duffing hysteresis, including multiple switching regions and isolated branches. Understanding how these structures are connected requires identifying the bifurcations that reorganize the response as the parametric excitation is varied. At a phase difference of 45 degrees between the direct and parametric excitations, we experimentally and analytically determine how the steady-state response changes as the parametric excitation is increased. A single resonance peak first splits into two while the response remains single valued. Two successive cusp bifurcations then create two saddle-node pairs and establish a double-hysteretic response. At the parametric-instability threshold, one saddle node of each pair is displaced towards unbounded amplitude and detuning, and an isolated-branch structure emerges above threshold. A parametric representation of the steady state distinguishes amplitude extrema from genuine saddle-node bifurcations and provides analytical conditions for these changes. Measurements on a dielectrically actuated pre-stressed SiN nanostring reproduce the predicted response and associated switching behavior. These results establish the bifurcation pathway connecting the different response structures at this phase configuration, providing a systematic basis for controlling multistability and switching in parametrically driven nonlinear resonators.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chaotic Dynamics (nlin.CD)
20 pages, 12 figures
Capturing Coordination Core Topology in Metal–Organic Frameworks Using Persistent Mayer Homology
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Caleb Simiyu Khaemba, Chun-Long Chen, Guo-Wei Wei
Local coordination cores are critically important in metal-organic frameworks (MOFs) and polyoxometalates (POMs), as they govern the fundamental chemical and structural properties of these materials. Existing methods, including element-resolved persistent homology (ERPH), have limited ability to translate local coordination cores into quantitative, scalable, and interpretable information. Here, we introduce persistent Mayer homology (PMH) to enable the detection of the geometric variability invisible by classical topology. By focusing on coordination cores formed by periodic metal-centered heavy-atom, carbon, and donor channels, PMH distinguishes different arrangements of the local coordination environment, linker framework, and potential coordinating atoms. We examine explainable PMH of orders $ N=3$ and $ N=5$ and separately combine each with ERPH, which characterizes the multiscale organization of chemically defined element groups across the extended framework, to predict eight nitrogen- and oxygen-related adsorption and self-diffusion properties. The resulting coordination-core PMH representations consistently improve predictive performance over ERPH alone, with the third-order Mayer representation providing the strongest overall performance. These results demonstrate that the inner coordination configurations captured by PMH contain essential structural information that is not fully represented by conventional element-resolved topological descriptors. This finding provides a quantitative interpretable topological framework for understanding local coordination environments and may facilitate the rational design of MOFs and POM-based materials.
Materials Science (cond-mat.mtrl-sci)
Symmetry-constrained coexistence of charge-three and charge-one Weyl points in nonmagnetic crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Ze-Xin Xue, Ke-Xin Pang, Yun-Yun Bai, Yanfeng Ge, Yan Gao
High-charge Weyl semimetals (WSMs), particularly those hosting charge-three Weyl point (C-3 WPs), have attracted considerable interest owing to their unconventional topological properties and enhanced boundary phenomena. However, ideal C-3 WSMs remain rare, and the symmetry-constrained coexistence of charge-three and charge-one Weyl point (C-1 WPs) in nonmagnetic crystals remains largely unexplored. Here, we investigate a representative eight-node Weyl configuration, consisting of two C-3 WPs and six C-1 WPs with opposite chirality, corresponding to two identical $ {3,-1,-1,-1}$ irreducible Weyl molecules. By combining topological charge conservation with space-group symmetry analysis, we systematically classify all 230 space groups and identify 12 and 23 candidate groups without and with spin–orbit coupling (SOC), respectively. First-principles calculations without SOC reveal that the boron allotropes TBR-B$ _{48}$ and chiral OBD-B$ _{48}$ realize this configuration, hosting hourglass-type and non-hourglass-type C-3 WPs, respectively. Surface-state calculations reveal six Fermi-arc branches at the shared projection of the charge-three pair and three at each individual projection. Reversing the structural chirality of OBD-B$ _{48}$ reverses the signs of all Weyl charges, establishing a direct correspondence between crystal and momentum-space chirality. Furthermore, breaking the protecting $ C_6$ symmetry in TBR-B$ _{48}$ splits each C-3 WP into three C-1 WPs and reconstructs the surface Fermi arcs. Our work establishes symmetry-based guidelines for designing and searching for nonmagnetic WSMs hosting charge-three and charge-one Weyl-point coexistence.
Materials Science (cond-mat.mtrl-sci)
4 figures
Non-volatile Orbital magnetoelectric effect in a two-dimensional electron gas
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Yu Chen, Martando Rath, Julien Brehin, Cinthia Piamonteze, Daniele Preziosi, Payal Wadhwa, Alessio Filippetti, Yuri Fukaya, Mario Cuoco, Filomena Forte, Daniela Stornaiuolo, Manuel Bibes, Marco Salluzzo
Electrical control of orbital magnetism is a central goal of orbitronics. While current-induced orbital polarization has recently been demonstrated in inversion-asymmetric systems, nonvolatile electrical control of an equilibrium orbital moment has remained elusive.
Here, using x-ray absorption spectroscopy with \textit{in situ} electric-field control of the FE polarization, we demonstrate non-volatile switching of the equilibrium orbital magnetization of the oxide q2DEGs formed at the LaAlO$ _3$ /EuTiO$ 3$ /Ca-STO (001) interface. X-ray linear dichroism reveals a reversible modulation, driven by the FE-polarization direction, of the Ti-3$ d$ crystal-field splitting and orbital occupancy, establishing a ferroelectric-like metallic state. X-ray magnetic circular dichroism shows a polarization-controlled switching of the Eu$ ^{2+}$ orbital magnetic moment induced by the orbital magnetization of the q2DEG projected onto Eu-5$ d$ states and detected at the Eu-$ M{4,5}$ edge through Eu-5$ d$ /Eu-4$ f$ hybridization in the inversion-symmetry-broken interface. These results provide spectroscopic evidence of ferroelectric control of orbital magnetism in an oxide q2DEG.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
11 pages, 6 figures, 1 Supplementary Material
Spin-orbit torque effects in all-electrical spin-wave spectroscopy experiments
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
José Solano Córdova, Jone Mencos, Richard Schlitz, Quentin Rossi, Denise Reustlen, Javed Ali, Sebastian Sailler, Michaela Lammel, Matthieu Bailleul, Daniel Stoeffler, Felix Casanova, Sebastian T. B. Goennenwein, Helena Reichlova
Electrical excitation and detection of propagating spin waves are key elements of magnonic devices. While conventional antennas consisting of non-magnetic metals such as Au or Cu excite spin waves predominantly through radio-frequency (RF) Oersted fields, antennas comprising Pt can additionally generate spin-orbit torques (SOTs) via the spin Hall effect. Recent theoretical work has proposed RF-SOT as an alternative mechanism for coherent spin-wave excitation, predicting distinct characteristics compared with conventional inductive excitation. Here, we investigate Pt antennas for the excitation of coherent spin waves in 105-nm-thick epitaxial $ \text{Y}_3\text{Fe}5\text{O}{12}$ (YIG) films through two potential mechanisms: an oscillating Oersted field and an oscillating spin current. The raw experimental transmission spectra are strongly affected by fabrication-induced modifications to the YIG film associated with the etching process together with spatially inhomogeneous interface conditions induced by Pt. After removing these contributions, we find the remaining two wave propagation consistent with a combined excitation from Oersted fields and SOTs.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Skyrmion gears: translation-to-rotation conversion of skyrmion clusters along periodic substrates
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
N. P. Vizarim, C. J. O. Reichhardt, C. Reichhardt
We investigate how the translational motion of a compact skyrmion cluster can be converted into collective rotation through interactions with a periodic obstacle substrate. Using an effective particle model, we consider a seven-skyrmion cluster driven along a one-dimensional array of repulsive obstacle sites. For suitable obstacle spacings and interaction strengths, repeated interactions with the substrate produce coherent clockwise or counterclockwise rotation, giving rise to gear-like cluster dynamics. We characterize these states using the translational velocity, Hall angle, angular velocity, structural deformation, and a dimensionless gear ratio that relates cluster rotation to motion over the substrate periodicity. Dynamical phase diagrams identify rotating, nonrotating, wall-guided, transverse, and deformed regimes. We further show that coherent rotation persists in the overdamped limit, demonstrating that the conversion mechanism does not require an intrinsic Magnus force and may therefore extend to other driven cluster systems, including colloidal assemblies. These results provide a simple route for controlling collective rotation through structured substrates.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
18 pages, 7 figures
H$2$-Like Units and Pressure-Tunable High-$T\mathrm{c}$ Superconductivity in NaH$_6$
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Hydrogen-rich materials offer a route to high-temperature conventional superconductivity, but often require extreme pressures. Here we report a first-principles study of NaH$ 6$ , identified in our large-scale hydride search and independently predicted in a subsequent high-throughput study. Several phases compete, with $ R\bar{3}m$ and $ Pm\bar{3}m$ dominant over broad pressure ranges. The $ R\bar{3}m$ phase remains dynamically stable down to 10 GPa, where its calculated $ T\mathrm{c}$ is 34 K, rising to 99 K at 50 GPa. Cubic $ Pm\bar{3}m$ becomes thermodynamically competitive at higher pressures and reaches a calculated $ T_\mathrm{c}$ of 230 K at 50 GPa, decreasing only weakly upon further compression. Molecular dynamics and phonon-renormalization calculations support structural persistence over the sampled timescale and indicate relatively small anharmonic effects. Despite their high $ T_\mathrm{c}$ , both phases contain elongated H$ 2$ -like units, often considered unfavorable for high-$ T\mathrm{c}$ hydrides. Mode-resolved electron-phonon coupling links Raman-active hydrogen vibrations to superconductivity. In $ R\bar{3}m$ , the linewidths of these modes increase with the pressure-induced tilt of H$ 2$ units relative to the threefold axis, alongside the rise in $ T\mathrm{c}$ . A minimal symmetry-based model of the vibration-induced second-moment tensor of the hydrogen sublattice shows that these trends are consistent with a significant contribution from response components perpendicular to the threefold axis. NaH$ 6$ thus represents an unusual molecular-like hydride in which hydrogen-sublattice reorganization may enable high-$ T\mathrm{c}$ superconductivity at comparatively moderate pressures.
Superconductivity (cond-mat.supr-con)
Comprehensive Workflow for Uncertainty-Aware Ionic Liquid Solvent Discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Alexander Lobo, Urvi Awasthi, Leonid Zhukov
Designing synthesizable materials with targeted properties remains one of the central objectives in materials sciences. Ionic liquids (ILs) are well suited to this goal due to their “tunability”, where physical and chemical properties can be precisely customized by modifying their molecular structure, specifically by varying the combination of cations and anions. At the same time, current data-driven property models for ionic liquids often degrade in scarce, noisy, and uneven data regimes, where measurements cover only a small fraction of chemical space and a limited range of thermodynamic conditions. This makes out-of-distribution screening brittle: even when point predictions look plausible, it is difficult to compare candidates consistently, quantify downstream implications, or trust rankings enough to guide molecular discovery. We present a property-prediction and optimal candidate selection workflow that treats data processing, deep learning modeling, and physics-based calculations as a coupled system, linking property prediction with uncertainty estimation and physics-based filtering. By tightening the link between predicted properties and the criteria used for down-selection, the workflow supports reliable out-of-distribution ranking and enables prioritization of previously untested ionic liquid candidates with favorable predicted trade-offs. We demonstrate the application of our workflow by designing novel ionic liquids for CO2 capture from flue gas, predicting their properties and selecting Pareto-optimal candidates based on CO2 solubility, IL viscosity and working capacity.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
10 pages, 5 figures, 5 tables. Accepted at IEEE ICDM 2026. Copyright 2026 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses
Spatial Engineering of Topological Quantum Matter with Structured Light
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Matias Mustonen, Ali G. Moghaddam, Teemu Ojanen, Marco Ornigotti
Structured light provides a powerful means of controlling matter while itself exhibiting nontrivial spatial topology. Here, we show that these spatial structures can be harnessed to locally engineer the topological properties of matter. In a paradigmatic example of a topological insulator with Dirac surface states driven by an optical skyrmion beam, we show that structured light spatially tailors the effective Hamiltonian, yielding position-dependent topological gaps and Dirac velocities. The resulting gap modulation can create topological and trivial regions separated by optically defined interfaces, without introducing material boundaries or chemical modifications. We further show that the geometry of these interfaces can be controlled through the spatial structure of the light, in particular its orbital angular momentum. Our results establish structured light as a route to dynamically pattern topological phases and open a broader perspective on the interplay between topology in light and matter, including the possibility of transferring topological characteristics between the two.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
4+4 pages, 4 figures
Revealing topological protection through unprotected operations in a Majorana parity qubit
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Sebastian Miles, Juan Daniel Torres Luna, Francesco Zatelli, Nick van Loo, Antonio Lombardi, Vincent P. M. Sietses, Florian J. Bennebroek Evertsz’, Bart Roovers, Leo P. Kouwenhoven, Michael Wimmer
A recent experiment reported coherent parity oscillations between minimal Kitaev chains, demonstrating a Majorana parity qubit (arXiv:2607.09511). Operations on this qubit are controlled by coupling two Kitaev chains and are intrinsically unprotected against noise in the coupling strength. Here we show how the exponential protection in the underlying chains can nevertheless be revealed through unprotected qubit operations. To this end, we develop an analytical theory of quasistatic dephasing for two coupled $ N$ -site Kitaev chains at the sweet spot. In Rabi experiments, protection can be resolved by adapting the operating point with chain length: depending on the coupling architecture, it appears as an exponentially increasing optimized number of coherent oscillations or as a longer coherence time. Ramsey experiments show an exponentially increasing coherence time, provided the chains can be sufficiently decoupled. Our analytical theory takes into account the non-Gaussian splitting statistics of the Kitaev chains, allowing us to quantitatively predict the scaling with chain length. Moreover, we determine how residual noise and imperfections limit the range of chain lengths over which this scaling can be observed. Our results show how qubit dynamics can be used to probe Majorana protection in experimentally realistic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
35 pages, 8 figures
Berry curvature from plane-wave mixing: A three-band model with emergent symmetries
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Two-dimensional materials can host topological phases stabilized either by an intrinsic moiré potential or topological crystallization. Crucial to the topology of these phases is the interplay between the (self-consistently generated) potential and the spinor structure, which imbues the band-projected potential with momentum-dependence. Truncating this potential at linear-order in momentum, we obtain a three-band model that captures the low-energy band structure and Berry curvature of such topological bands. We analytically find that the Berry curvature strongly depends on momentum-dependence of the potential. Furthermore, we identify that the model can be tuned to have emergent symmetries, including $ U(1)$ and anti-unitary symmetries. Emergent-symmetry breaking perturbations drive the system to regimes hosting topological flat bands, quadratic band touchings, and multiple Dirac cones. We recover many of these features when studying an un-truncated model of a $ \lambda$ -jellium spinor inside of a periodic potential. Our results reveal a rich interplay of spinor structure and a potential in determining the topology of the ground state.
Strongly Correlated Electrons (cond-mat.str-el)
Pairing from repulsive interactions in twisted WSe2 from functional renormalization
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Hannes Braun, Dumitru Călugăru, Pietro M. Bonetti, Haoyu Hu, Yan Zhang, Yi Jiang, Quansheng Wu, Kin Fai Mak, Jie Shan, B. Andrei Bernevig, Michael M. Scherer, Laura Classen
Motivated by the observation of superconductivity in twisted bilayer WSe$ _2$ over an extended range of displacement fields, reaching from the correlated insulator down to zero field, we analyze the correlated electron phases of this system at hole filling $ \nu = -1$ and twist angle $ 3.65^\circ$ using Hartree–Fock, random phase approximation, and functional renormalization group calculations. We derive a continuum model with gate-screened Coulomb interaction from first principles and compare its instabilities to those of a realistic three-orbital Wannier model with a Hubbard interaction and an artificial single-orbital Hubbard model. In both cases, we find a superconducting instability of mixed $ d$ -wave singlet and $ p$ -wave triplet character, arising adjacent to inter-valley-coherent spin-density-wave order in the phase diagram spanned by displacement field and interaction strength. Our additional analysis of the pairing mechanism points to inter-valley coherent spin fluctuations as the pairing glue. The extent of the pairing regime and the associated critical temperatures depend on the model input, and we trace differences to the interaction range entering the projected interaction. Within the continuum model, the gate-screened Coulomb interaction yields pairing down to zero displacement field, bringing theory into agreement with experiment.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
9+50 pages, 3 + 31
Turning a superconducting diode into a Feynman ratchet to realize a nanoscale heat engine
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Konstantinos Kontogeorgiou, İnanç Adagideli, Géraldine Haack, Fabian Hassler
Feynman’s ratchet illustrates how work can be extracted from thermal fluctuations in the presence of two heat baths at different temperatures. While some experimental realizations of the ratchet effect have been studied, most lack miniaturization, which is important for some applications. Here, we propose a physical implementation of Feynman’s ratchet based on Josephson junctions exhibiting the superconducting diode effect. This setup functions as a heat engine that generates work solely from a temperature gradient via thermal fluctuations. We analyze its output power and efficiency, and, through the Seebeck coefficient, identify the conditions under which the device operates in reverse, functioning instead as a Peltier cooler.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Phase-Coherent Spin and Lattice Modulations in a Y-type Hexaferrite
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Oskar Stepančić, Annika Stellhorn, Emma Campillo, Kun Zhai, Niklas Ekström, A. Corani, D. Alba Venero, R. Cubitt, E. Blackburn, L. Shen
Spin-driven multiferroics owe their electric polarization to lattice distortions that follow the magnetic order, yet in incommensurate magnets symmetry normally forbids such a distortion at the fundamental magnetic wavevector, and the distortions themselves are rarely observed. Here we use half-polarized neutron scattering to show that the Y-type hexaferrite Ba$ _{0.4}$ Sr$ _{1.6}$ Mg$ _2$ Fe$ _{12}$ O$ _{22}$ hosts, in its saturated high-field state, a magnetic modulation and a longitudinal lattice modulation at one and the same wavevector, locked in phase. The signature is a large nuclear-magnetic interference asymmetry, $ r$ ~ 0.8, of the same sign at the two conjugate satellites and persisting to 275 K. The zone contrast and the field dependence of the satellite indicate an internal, field-induced longitudinal distortion. The modulated state coexists with the transverse-conical magnetoelectric phase and outlives it, revealing a fundamental-wavevector spin-lattice coupling in a magnetic field regime previously regarded as a simple ferrimagnet.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Quantum skyrmion molecule: two quantum skyrmions bound by coherent magnon exchange
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Quantum skyrmions in frustrated spin-$ 1/2$ magnets are bound states of a few flipped spins in a ferromagnetic background. Using exact diagonalization and density-matrix renormalization group calculations for the $ J_1$ –$ J_2$ triangular-lattice model with easy-axis anisotropy $ K$ , we ask what happens when two such objects are brought together. The binding energy per flipped spin of a single skyrmion has a minimum at $ \Nf^{\ast}=7$ for $ K=0.02$ –$ 0.04$ , and skyrmions smaller than $ \Nf^{\ast}$ do not exist as pairs: at any distance they coalesce into a single larger object, and pinning wells cannot prevent it. Two skyrmions of natural size, by contrast, form a bound molecule without pinning or external field, with binding energy $ U\simeq-0.007J_1$ at $ K=0.03$ –$ 0.04$ and an equilibrium separation of $ 5.5$ lattice spacings that does not depend on $ K$ or on the size of the simulation domain; at $ K=0.02$ , where the single skyrmion is itself marginally bound, the pair is unbound within our resolution. The two constituents keep their identity ($ 7+7$ flipped spins) and are coupled by a coherent exchange of magnons, visible as number fluctuations between the two halves of the domain in excess of those of two independent skyrmions and as in-plane spin correlations between the two skyrmion walls that reach $ 0.16$ across the gap. These correlations follow the vortex pattern of the two textures and lock their relative helicity, the quantum counterpart of the helicity-dependent interaction of classical skyrmions. We discuss the molecule as a self-assembled two-qubit element for skyrmion helicity qubits in a single layer.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
Evidence of an anisotropic Griffiths phase in a two-dimensional van der Waals magnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Anupam K. Singh, Dhananjay Nair, Holger Meyerheim, Stuart S. P. Parkin, Banabir Pal
Over the last decade, the emerging field of two-dimensional van der Waals magnetism has focused mainly on long-range-ordered magnetic phases. Disordered magnetic phases, however, remain largely unexplored. Here, we report a highly anisotropic Griffiths phase driven by self-intercalation in the van der Waals magnet Fe5GeTe2. We find evidence of short-range-ordered ferromagnetic clusters embedded in a paramagnetic matrix, which dominate the magnetic response between the Curie temperature and a higher characteristic Griffiths temperature. An anomalous power-law divergence in the magnetic susceptibility, universal Lee Yang scaling, and distinct entropy anomalies provide further evidence for this phase. Strikingly, the non-analytic Griffiths response emerges exclusively under in-plane magnetic fields, whereas out-of-plane fields abruptly alter this behavior. This directional dependence indicates that the local magnetic interactions within nanoscale clusters are closely coupled to the layered lattice geometry. Our findings establish a regime of dimensionally constrained, disorder-driven magnetism and identify self-intercalated van der Waals magnets as a platform for investigating the interplay between magnetic disorder, anisotropy, and reduced dimensionality.
Materials Science (cond-mat.mtrl-sci)
15 pages, 4 figures
Machine-learned topological transport of magnetic colloids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Sebastian Wohlrab, Aneena Rinu Perayil, Piotr Kuświk, Maciej Urbaniak, Feliks Stobiecki, Arne J. Vereijken, Arno Ehresmann, Thomas M. Fischer, Daniel de las Heras
By modulating the orientation of a uniform magnetic field it is possible to transport magnetic microparticles above magnetic patterns. In periodic patterns, driving control loops that wind around special orientations, which are dictated by the symmetry of the pattern, induce transport by one unit cell. The transport is topologically protected with trajectories controlled by the winding numbers of the control loop around the special orientations. In non-periodic patterns, the special orientations are position dependent, precluding a global characterization of the transport using a small set of winding numbers. We use here a reinforcement learning agent trained with Brownian dynamics simulation data that uses the local environment of the magnetic pattern to decide an action over the control loop. The agent autonomously discovers topological transport protocols directly from the particle response without prior characterization of the magnetic potential landscape. An agent trained solely on a complex non-periodic pattern directly generalizes to completely unseen periodic, quasicrystalline, and disordered substrates. Moreover, the agent dynamically adjusts the control loop to transport particles across lattice defects and to counterbalance external drift forces that would cause static topological loops to fail. By adding a pathfinding algorithm to the model, we additionally achieve simultaneous, independent transport of multiple identical colloids along different on demand trajectories. We demonstrate that the control loops can be directly transferred to an experimental setup to successfully drive magnetic microparticles across a non-uniform magnetic thin film.
Soft Condensed Matter (cond-mat.soft)
Can Universal Machine-Learning Interatomic Potentials Capture Small Polarons? A Geometry-Based Benchmark in Transition-Metal Oxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Vladislav Korostelev, Pjotrs Žguns, Konstantin Klyukin
Small polarons, formed when excess electrons become localized through lattice distortions, play a critical role in charge transport, catalysis, and degradation processes in transition-metal (TM) oxides. Whether universal machine-learning interatomic potentials (uMLIPs), which lack explicit electronic degrees of freedom, can describe them remains unclear. Here, we investigate H-induced electron localization across a range of TM oxides using a geometric descriptor based on TM-O bond-length expansion (Z-score) to identify polaronic distortions. We find that uMLIPs exhibit varying degrees of electron localization, from delocalized states to metastable small polarons, with their behavior strongly dependent on the training data and treatment of electronic correlations. In particular, the absence of Hubbard U corrections for specific TM cations in the training data leads to electron delocalization, in contrast to DFT+U predictions. Although some uMLIPs reproduce polaron hopping barriers during coupled proton-polaron transfer, all of them fail to stabilize spatially separated polaron-donor configurations, instead favoring localization near the H dopant.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
19 pages, 5 figures; Supporting Information (11 pages, 6 figures) appended at the end
Meso-scale modeling of cohesive cavitation in polymer networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Saleh Assadi, Zachary T. White, Fay Salmon, Nitin Hansoge, Zhuonan Liu, Victor Crespo-Cuevas, Jason Clapper, Nikolaos Bouklas, Franck J. Vernerey
Cavitation influences the failure of elastomers and soft adhesives, but connecting its microscopic initiation to subsequent cavity growth remains challenging. Here, we develop a discrete mesoscale framework that combines finitely extensible, breakable strands with local van der Waals interactions to examine how cohesion and network heterogeneity transform distributed dilation into localized damage. In the simulations, local cohesive instability produces a network-scale precursor whose subsequent expansion is coupled to strand stretching and rupture. Cohesive strength and intrinsic defect size govern the critical hydrostatic tension, while cohesion also controls the number and spatial distribution of cavities. Under confined loading, decreasing the layer thickness promotes multiple cavities and distributed strand rupture, extending the load-bearing response and increasing the critical work density of rupture. An energetic interpretation based on the thickness dependence of the crack-driving force connects these observations to competition between additional cavity nucleation and propagation of existing damage. The results link local cohesive instability to the collective evolution of cavities and rupture in disordered polymer networks.
Soft Condensed Matter (cond-mat.soft)
Saleh Assadi and Zachary T. White have contributed equally to this work
Collision Cascade Morphology and Defect Nucleation in Pure Tungsten and an Equimolar Refractory W-Ta-Cr-V Alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Mark Fedorov, Francisco Javier Dominguez-Gutierrez
Collision cascades and defect-formation mechanisms in pure W and the WTaCrV refractory high-entropy alloy were investigated using molecular dynamics simulations over primary knock-on atom (PKA) energies of 0.1-100 keV. Machine-learning tabulated Gaussian approximation potentials (tabGAP), complemented by short-range Ziegler-Biersack-Littmark (ZBL) interactions, were employed. Analysis of the heat spike lifetime, affected region, atomic relocations and surviving defects reveals an importance of subcascade formation and presence of light elements in the alloy. Cascade splitting into subcascades contributes to the distribution of the PKA energy over a larger region in the material, nucleating less dislocations and smaller voids - latter being present only in W and absent in WTaCrV. Since cascade splitting is more frequently observed in WTaCrV, the alloy shows better resistance to primary irradiation damage compared to pure W. Apart from cascade splitting, analysis of interstitials shows that Cr and to lesser extent V, being lighter and smaller elements, accommodate the damage in form of point defects, contributing to the mitigation of formation of the dislocation loops.
Materials Science (cond-mat.mtrl-sci)
11 pages, 10 figures, 1 table
High-Resolution X-ray Spectro-Microscopy of Au Microcrystallites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Chaitali Sow, Martin Seyrich, Johannes Hagemann, Giridhar U. Kulkarni, Thomas F. Keller, Christian G. Schroer, Andreas Schropp
Understanding the functionalities of heterogeneous catalysts requires high-resolution nanoscale chemical imaging tools. X-ray spectro-ptychography offers this capability by enabling X-ray absorption near edge structure (XANES) based amplitude and phase contrasts imaging with high spatial resolution. However, such demonstrations at energies above 10 keV, such as the Au L-edges, remain limited due to weak X-ray absorption cross-sections and correspondingly, low signal levels. Here, multimodal spectro-microscopy has been performed on Au microcrystallites that host both conventional face-centered cubic (fcc) and unconventional non-cubic lattices, particularly important for catalysis. Amplitude and phase contrasts across the $ \mathrm{L}_3$ edge are resolved on thin Au crystallites (150 nm to 1.71 $ \mu\mathrm{m}$ ) with 45 nm spatial resolution. The resulting XANES spectra exhibit excellent agreement with standard transmission and fluorescence contrasts, while providing complementary chemical insights with improved spatial resolution. Quantitative retrieval of anomalous phase variations ~12 keV further demonstrates the suitability of this method for high-resolution chemical imaging across a wide range of functional materials.
Materials Science (cond-mat.mtrl-sci)
31 pages, 6 figures
Crystal growth, magnetic, and transport properties of the candidate altermagnet Cr${1/4}$NbS${2}$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Nashra Pistawala, Martin R. Lees, Geetha Balakrishnan, Daniel A. Mayoh
Altermagnetism is a rapidly emerging paradigm in condensed matter magnetism, yet the number of experimentally confirmed altermagnetic candidates remains remarkably limited. Cr$ _{1/4}$ NbS$ _2$ has long been theoretically proposed as a promising altermagnet, but there are no reports on experimental investigation of single crystals. Here, we report the successful growth of high-quality single crystals of Cr$ _{1/4}$ NbS$ _2$ and present its structural, thermal, magnetic, and transport properties. Single-crystal X-ray diffraction provides detailed crystallographic information and confirms the hexagonal crystal symmetry ($ P6_3/mmc$ ), one of the criteria for altermagnetic behavior. Resistivity and heat capacity measurements unambiguously identify an antiferromagnetic Néel temperature of $ T_N \sim 141$ K. Magnetotransport measurements reveal non-trivial features in the magnetoresistance and Hall response, indicative of quantum diffusive transport phenomena. Cr$ _{1/4}$ NbS$ _2$ , synthesized here for the first time in single-crystalline form, therefore serves as an experimental platform for probing the rich spectrum of phenomena predicted for altermagnetic materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
26 pages, 5 figures
Energy levels of screened charged impurity in gapped graphene under magnetic field
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
In this paper, we present a comprehensive theoretical study of the electronic states in gapped graphene in the presence of a charge impurity and a magnetic field. We focus on the impurity-induced modification of the Landau levels under the influence of an attractive or repulsive Coulomb potential. Since analytical solutions of the Dirac equation are not available in this case, the study is carried out using the Wentzel-Kramers-Brillouin (WKB) approach. Special attention is paid to the screening of the Coulomb potential in the presence of metallic gates situated at some distances from graphene sheet, as is commonly the case in experiments. Using both analytical and numerical methods, we determine the energy spectrum as a function of the magnetic field strength and impurity charge for screened and unscreened Coulomb potentials. Our results reveal a significant dependence of the energy levels for sample-to-gate distances of less than 50 nm.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
18 pages, 5 figures
Electric Edelstein Effect in Two Dimensions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Xiaoran Lv, Tianqi Zhang, Chaoxi Cui, Yaling Li, Yi Shen, Weikang Wu, Ziming Zhu, Yugui Yao, Zhi-Ming Yu
We propose the electric Edelstein effect (EEE) in two-dimensional (2D) systems, where crossed out-of-plane and in-plane electric fields generate a spin polarization. The gate field converts the Edelstein response from a material-fixed spin polarization into a gate-tunable one. A symmetry analysis over all magnetic layer point groups shows that the EEE is allowed in a wide range of magnetic and nonmagnetic systems, including ferromagnets, antiferromagnets, and altermagnets. The EEE plays two distinct roles: it generates spin polarization where the linear Edelstein effect (EE) is symmetry-forbidden, as in centrosymmetric materials; and it adds a new gate-tunable component, generally non-collinear with the conventional one, where the EE is already present. The two fields then act as independent knobs and raise the control dimension of the spin polarization from one to two. Our microscopic theory traces the EEE to band-geometric quantities, which are strongly enhanced near small band gaps. First-principles calculations predict pronounced effects in the centrosymmetric ferromagnet MnSe2, where the linear EE is symmetry-forbidden. In the nonmagnet SnSe where the EE and EEE coexist, the two knobs cover an extended region of the spin sphere. Our findings establish the EEE as a symmetry-guided, gate-tunable route to electrical spin manipulation and open avenues for multistate spintronics in 2D quantum materials.
Materials Science (cond-mat.mtrl-sci)
A grand potential for molten-salt electrochemical phase diagrams from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Lorenzo Bastonero, Lucio Colombi Ciacchi, Nicola Marzari
The clean-energy transition is driving unprecedented demand for metals, whose extraction is among the largest industrial sources of carbon emissions. Molten-salt electrolysis offers a path toward carbon-free production of aluminum, iron, titanium, and critical metals. However, corrosive operating conditions and complex, multicomponent feedstocks make experimental development costly and challenging. Here, we introduce a first-principles framework for constructing electrochemical phase diagrams of multicomponent systems to accelerate electrode and electrolyte design and guide the selection of compatible materials and operating conditions for electrochemical cells. We derive a grand potential that generates these diagrams at scale, and supply free energies using first-principles data obtained through a fine-tuned foundation machine-learned interatomic potential. For silicon in molten CaCl$ _2$ , the construction not only recovers the experimental diagram when using the first-principles framework on a limited set of structures, but also predicts further domains when extended to a larger set of crystal structures. Finally, we demonstrate the predictive power of the approach by screening ten alkali and alkaline-earth halide electrolytes for aluminum electrowinning. Three thermodynamic criteria identify NaF, where cryolite emerges as the stable aluminum-bearing phase, recovering the chemistry that Hall and Héroult established empirically in 1886. The framework provides a first-principles basis for selecting compatible electrodes, electrolytes, and operating conditions toward low-carbon metal production from complex source materials.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
A Parameter-Free Reference Hamiltonian for Tight-Binding Vanadium Oxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Density-functional tight binding has yet to yield a transferable description of vanadium oxides; for the standard second-order construction and the tested cells, we demonstrate that two of its approximations deviate by electron volts and offset each other in the band-index centroid separation between the V 3d and O 2p bands: the neutral two-centre reference omits electron-volt environmental terms, whereas the Mulliken charge model assigns the compact V 3d shell less than half of the self-consistent potential shift observed in PBE. Instead, we build a tight-binding model where the reference Hamiltonian derives from superposed neutral atoms, the full PBE exchange-correlation potential and frozen-core orthogonality, without adjustable terms, and where the orbital-resolved charge response employs three screening factors obtained from PBE linear response and an unscreened Coulomb range. Against the primary PAW reference, the reference energy at fixed geometry and the stated numerical settings matches the plane-wave Harris-Foulkes energy differences of VO2, exhibiting signed deviations of +2.6 meV/atom for M1 relative to rutile (an energy difference of 92 meV/atom) and +6.2 and -5.2 meV/atom under 3% volume compression and expansion; meanwhile, the charge response captures 21 of 22 fitted and all 8 held-out matched PBE responses within tolerance, providing the V 3d shell with nearly the same self-consistent shift as PBE (-3.89 versus -3.92 eV in rutile). The convexity of the spinless model at fixed geometry prevents it from spontaneously differentiating symmetry-equivalent sites under the symmetries respected by its implemented operators and sampling, so within this model such differentiation in the Magnéli phases must arise from electron-lattice coupling or an explicit spin or correlation term.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
27 pages, 4 figures, 4 tables; Supporting Information as an ancillary file; model parameters at this https URL
Observation of stacked vortex structure with number controllable Majorana zero mode in Bi${2}$Te${3}$/FeTe heterojunction
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Xinru Han, Zhaokun Luo, Quanxin Hu, Xingjian Zhu, Xiaohong Pan, Dan Mu, Xinyu Liang, Zulin Xu, Qiheng Wang, Ryan L. Kong, Mingyuan Li, Zhengliang Zhang, Fazhi Yang, Mojun Pan, Xin Liu, Qiangqiang Gu, Baiqing Lv, Gan Wang, Hong Ding
Creation and control of Majorana zero modes (MZMs) in solid devices is the key challenge in realizing fault tolerant topological quantum computation. Here we report spectroscopic evidence for number controllable MZMs in stoichiometric one quintuple layer Bi$ _{2}$ Te$ _{3}$ /FeTe heterostructures, together with the observation of stacked vortices in superconducting islands. Low temperature scanning tunnelling microscopy and spectroscopy reveal a long period moire superlattice arising from lattice mismatch, which induces nanoscale modulation of superconducting gaps. Magnetic vortices exhibit a stacked core structure with two layer derived bound state branches: a dispersive branch evolving into an X-shaped pattern away from the vortex center, and a quantum-limit branch characterized by a spatially unsplit MZMs together with discrete integer quantized Caroli-de Gennes-Matricon states. Notably, MZMs are observed in all measured vortices, and their number can be tuned by magnetic field and the size of Bi$ _{2}$ Te$ _{3}$ islands. These results establish stoichiometric 1QL-Bi$ _{2}$ Te$ _{3}$ /FeTe as a patterned superconducting interface that enables isolated and few-vortex Majorana configurations, providing a controlled platform for fuse MZMs.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Under review
A Full-Spectrum Theory of Moiré Superlattices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Tong Liu (1 and 2), X. R. Wang (3), Jiansheng Wu (1) ((1) Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, China, (2) Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China, (3) School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, China)
Conventional theoretical descriptions of moiré superlattices, epitomized by the Bistritzer–MacDonald continuum model, are fundamentally constrained by low-energy Dirac cone approximations and first-shell interlayer coupling truncations. While successful for small-angle twisted bilayer graphene near charge neutrality, these frameworks fail to provide universal analytical solutions for strained lattices, high-energy band behaviors, or arbitrary commensurate geometries. Here, we establish a unified, approximation-free analytical formalism for generalized moiré systems based on three pillars: (i) a rigorous two-dimensional-to-one-dimensional supercell cyclic mapping, (ii) exact block-circulant diagonalization of intralayer Hamiltonians, and (iii) quasi-degenerate Löwdin perturbation theory centered on arbitrary energy degeneracy points across the full spectrum. Unlike traditional schemes anchored to the Dirac point, our approach enables systematic perturbative expansions around any band crossing, unifying the characterization of low-energy flat bands with high-energy degeneracies. We demonstrate that this framework perfectly recovers the Bistritzer–MacDonald model in the low-energy limit while extending its reach to heterostrained systems and high-energy regimes. By incorporating high-order interlayer coupling shells, we reveal an intrinsic scale self-similarity in moiré lattices and predict the emergence of higher-order magic angles and tunable flat bands driven by secondary degeneracies. This work eliminates the long-standing lack of universal analytical tools for diverse moiré platforms, providing a full-spectrum theoretical foundation for band engineering and the exploration of exotic correlated and topological states in van der Waals heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
21 pages,13 figures
Hydrogen-Bond Density Drives the Order-Disorder Phase Transition from Orientational to Vibrational in Polyalcohol Plastic Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Ares Sanuy, Carlos Escorihuela-Sayalero, Pol Lloveras, María del Barrio, Hassan Allouchi, Josep-Lluís Tamarit, Luis Carlos Pardo, Claudio Cazorla
Neopentane-derived plastic crystals undergo order-disorder phase transitions accompanied by exceptionally large entropy changes, making them attractive solid-state materials for thermal energy storage and barocaloric cooling. Yet it remains unclear whether the microscopic nature of this entropy change is an intrinsic property of each compound or can be understood generally and tuned systematically through molecular design. Here, we use classical molecular dynamics simulations of neopentyl glycol (NPG), pentaglycerine (PG), and pentaerythritol (PE), validated against experimental transition temperatures, enthalpy changes, and phase diagrams, to show that the character of the phase-transition entropy undergoes a complete inversion as the hydrogen-bond connectivity of the molecule increases: orientational disordering dominates in NPG, whereas lattice vibrations dominate in PE and become remarkably robust against pressure. PG occupies a balanced intermediate regime in which the orientational, conformational, and vibrational channels contribute comparably. This inversion reflects two coupled microscopic mechanisms: a growing low-frequency gap between the phonon densities of states of the ordered and disordered phases as the hydrogen-bond network densifies, and an increase in molecular symmetry that progressively suppresses orientational disordering. Because the vibrational channel is substantially less sensitive to pressure than the orientational one, hydrogen-bond density emerges as a practical, chemically accessible design handle for tailoring not only the magnitude but also the pressure robustness of the caloric response in hydrogen-bonded plastic crystals, with direct implications for the search for new barocaloric and thermal-energy-storage materials.
Materials Science (cond-mat.mtrl-sci)
11 pages, 5 figures
Skin phase transition of a skyrmion in a ferromagnetic superfluid
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-14 20:00 EDT
Wooyoung Yun, Se Kwon Kim, Hiromitsu Takeuchi
Compared with a scalar Bose-Einstein condensate (BEC), a spinor BEC supports richer phenomena because of its internal spin degrees of freedom, including topological solitons such as domain walls or skyrmions. Here, we theoretically reveal three distinct axisymmetric soliton structures formed as a circular domain wall in a spin-1 BEC, connected within fixed winding numbers. We refer to these structures as the broken-axisymmetry (BA)-skin, antiferromagnetic (AF)-skin and normal-core phases. Their occurrence is controlled by the two dimensionless parameters in the absence of linear Zeeman coefficient $ p=0$ : $ q/\mu$ , the ratio of the quadratic Zeeman coefficient to the chemical potential, and $ c_s/c_n$ , the ratio of spin interaction to the density interaction. The BA-skin and AF-skin phases exhibit local easy-plane magnetic order and local easy-plane spin-nematic order, respectively, while the normal-core phase is similar to a doubly quantized vortex analogous to that of a scalar BEC with a density depletion at the center. We obtain semi-analytical estimates of selected transition boundaries separating these phases by analyzing the Bogoliubov-de Gennes equation and also numerically confirm them by solving the Gross-Pitaevskii equation. We estimate the skyrmion radius using a hydrostatic approximation and compare the result with numerical solutions. We envision our results on skyrmions in a spin-1 BEC can trigger further investigation on novel soliton structures in a magnetic superfluid.
Quantum Gases (cond-mat.quant-gas)
Proof of the exact correlation-length exponent $ν= \frac{\sqrt[3]{2}}{2}$ and algebraic relations for $β$ and $γ$ in the 3D Ising model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Based on our previous results regarding critical exponent estimates for the 3D Ising model and scaling relations [1], we have proven that the exact value of the correlation-length exponent is $ \frac{\sqrt[3]{2}}{2}$ . This is in very close agreement with the most precise numerical estimates currently available. Using a group theoretical approach and some propositions of constructive geometry, we derived an exact construction of algebraic expressions for the critical exponents $ \gamma$ and $ \beta$ . We proved that these expressions depend solely on the exact value of $ \nu,$ .
Statistical Mechanics (cond-mat.stat-mech)
Learning from fracture: Teaching language models to design through physical experience
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
How can language models learn to optimize physical designs through experience? We introduce FracLearn, an experience-abstraction-generalization framework evaluated through a deliberately unfamiliar, Tetris-inspired fracture game. The model first proposes architectures and examines simulated fracture responses to accumulate experience. Abstraction organizes these observations into conditional principles linking reinforcement placement, crack evolution and load transfer, with supporting evidence and failure conditions. Generalization challenges the model to combine these principles in new architectures and surpass the earlier design record. Campaigns demonstrate progressive refinement and recovery through hypothesis revision, yielding a best composite score 11.0% above the experience-stage record. Fracture analyses connect improved performance to crack deflection and temporary trapping as toughening mechanisms, alongside greater residual load capacity. Learning occurs through external knowledge and decisions, without model-weight updates. This approach offers a route to scientific agents that turn computational experiments into reusable physical knowledge for materials discovery and engineering design.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI), Machine Learning (cs.LG)
21 pages, 7 figures, 3 tables. Includes Supplementary Materials
Polarons in Lead-Halide Perovskites: What the Structural Evidence Does and Does Not Establish
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Inhee Maeng, Young Mi Lee, Jinwoo Park, Seung Jae Oh, Min-Cherl Jung
Photogenerated carriers in lead-halide perovskites are widely believed to move as large polarons, whose accompanying lattice distortion is thought to screen the carrier from charged defects. Three recent findings call this picture into question. First, time-resolved structural probes now measure the photoinduced lattice distortion directly; yet calculations show that thermal motion of the lattice alone can raise the carrier effective mass-an increase previously taken as evidence for polarons-so that it remains unclear whether the lattice distortion around a carrier is really a polaron. Second, the carrier-lattice coupling strengthens as the material is thinned from 3D to 2D. In the two main families of 2D perovskites, Ruddlesden-Popper and Dion-Jacobson, the carrier couples to the lattice through different channels, and their contrasting behavior is set by which coupling channel dominates rather than by lattice stiffness alone. Third, the first direct test of defect tolerance does not point to polaron screening; its authors attribute defect tolerance to the soft, disordered lattice. New transport data show that polaron screening reduces scattering between carriers, but not that it protects carriers from defects. Polaron formation, even if established, therefore does not establish polarons as the cause of defect tolerance. Separating the two requires measuring the lattice distortion as a function of excitation density, over a range spanning the low densities of a solar cell under sunlight and the much higher densities used in most ultrafast experiments. On this basis, we propose experiments that can clarify how photogenerated carriers behave in lead-halide perovskites.
Materials Science (cond-mat.mtrl-sci)
28 pages, 10 figures
Orthoexciton-to-paraexciton conversion rate in Cu$_2$O at sub-Kelvin temperatures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Yusuke Morita, Yukihiro Akiyama, Yuki Haita, Yuga Hirota, Kosuke Yoshioka
We measured the conversion rate from 1s orthoexcitons to 1s paraexcitons in Cu$ _2$ O below 1 K using a dilution refrigerator. To determine the conversion rate, we performed time-resolved luminescence spectroscopy of 1s orthoexcitons and 1s paraexcitons confined in a strain-induced trap potential. From the time evolution of the $ {\Gamma}$ _3$ ^{-}$ -LO-phonon-assisted luminescence of 1s orthoexcitons, we obtained a conversion rate of $ 5.9 \times 10^7$ s$ {^{-1}}$ at a mixing-chamber temperature of 64 mK under an applied stress of 2.2 kbar. Between 64 and 800 mK, the conversion rate depends only weakly on temperature, and it is less than half of the value of $ 1.6 \times 10^8$ s$ {^{-1}}$ reported at 2 K under the same applied stress. The conversion rate therefore continues to decrease below 2 K, contrary to the previous expectation that it becomes nearly constant below about 1.7 K. We discuss these results in terms of the momentum distribution of orthoexcitons, which does not reach equilibrium with the lattice during the conversion at these low temperatures. These findings call for a theory that accounts for both the small magnitude of the conversion rate and its weak temperature dependence below 1 K.
Materials Science (cond-mat.mtrl-sci)
11 pages, 5 figures
Colossal Spin–Lattice–Charge Coupling in Noncollinear Ferrimagnetic NbMnX$_2$ ($X$ = S, Se, Te) Monolayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Peng Wang, Nanshu Liu, Hongkuan Yuan, Xue Jiang, Jijun Zhao
Noncollinear ferrimagnets combine a net magnetic moment with internal spin degrees of freedom, creating opportunities to couple magnetic, mechanical, thermal, and electronic responses. Using first-principles calculations, symmetry analysis, atomistic spin simulations, and transport modeling, we identify stable NbMnX$ _2$ ($ X$ = S, Se, Te) monolayers with noncollinear ferrimagnetic ground states and Curie temperatures up to 313 K. Competing exchange, Dzyaloshinskii–Moriya interactions, and magnetic anisotropy produce field-responsive canted states that couple strongly to the lattice and charge carriers. Magnetization rotation changes the elastic modulus of NbMnTe$ _2$ by up to 36%, while lattice entropy substantially enhances the near-room-temperature magnetocaloric response of NbMnS$ _2$ and NbMnSe$ _2$ . In NbMnSe$ _2$ , rotation restores a mirror-protected crossing, continuously closes an approximately 0.13 eV gap, and produces a conductivity-based anisotropic magnetoresistance ratio up to 10,000% at 100 K. The combined results establish noncollinear NbMnX$ _2$ monolayers as a multifunctional platform for two-dimensional spintronics, nanomechanics, and thermal control.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
11 pages, 4 figures
ARES: a plane-wave density-functional-theory code in Rust
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Zehan Liu, Qian Wang, Xiangyu Zheng, Jiaxiang Li, Chuntian Wu, Yongshuo Chen, Xuecheng Shao, Qiang Xu, Yu Xie, Yanming Ma
ARES (Ab initio atomic mateRial modEling Software at JLU) is a plane-wave density-functional-theory (DFT) code written entirely in Rust as a layered 22-crate workspace. It supports norm-conserving pseudopotentials and the projector augmented-wave (PAW) method with the local-density approximation (LDA) and Perdew-Burke-Ernzerhof (PBE) functionals, {\Gamma}-only and explicit k-point sampling, smearing and mixing, forces, stress, relaxation, band structures, densities of states (DOS) and dispersion corrections; execution is serial or MPI-distributed over k-point pools, band groups and plane-wave rows. The code’s distinguishing engineering choice is its validation apparatus. Every numerical component is checked against Quantum ESPRESSO driven from the same physical and numerical inputs, and the comparison is organized as numbered fixtures kept in the repository whose reference data is regenerated by a script instead of being captured once. On six materials spanning a semiconductor, three metals and two two-dimensional systems, band energies within one electronvolt of the Fermi level agree with the reference to a median below 0.4 meV. The pseudopotentials the code reads are validated against all-electron reference data as well: the median delta factor is 0.696 meV/atom over all 65 paired elements. Restrictions are stated with the capabilities: two functionals, no spin-polarized or spin-orbit path, a stress implementation with an explicit scope, and no accelerator execution.
Materials Science (cond-mat.mtrl-sci)
19 pages, 2 figures
Imaging atomic-scale surface structure and superconducting gap of the misfit layered compound (SnS)1.17NbS2
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Dongming Zhao, Shamarita Deb, Lichen Ji, Souvik Das, Paul Simon, Raúl Cardoso-Gil, Steffen Wirth, Walter Schnelle, Sushmita Chandra, Jian-Feng Ge, Claudia Felser
Superlattices of van der Waals-coupled two-dimensional materials offer a platform for engineering electronic band structure and fostering emergent quantum states. Misfit layered compounds provide naturally assembled superlattices, in which crystallographically distinct two-dimensional subsystems coexist within a single bulk crystal. Therein, the presence of both commensurate and incommensurate lattice directions introduces structural modulation, which might alter real-space electronic orders such as superconductivity. Here, we investigate the atomic-scale surface structure and local superconductivity of the misfit layered compound (SnS)1.17NbS2 using structural characterization, electrical transport, and low-temperature scanning tunnelling microscopy (STM). While X-ray diffraction and cross-sectional scanning transmission electron microscopy confirm the bulk misfit structure, STM resolves large SnS- and NbS2-terminated terraces, where the surface atomic registry differs from the bulk misfit structure. Furthermore, tunnelling spectroscopy at 2 K reveals nearly identical superconducting gaps on both terminations, and the spatial variation of the gap shows no visible modulation that corresponds to the misfit lattice. These results establish an atomic-scale picture of the surface structure and superconducting states of this naturally assembled misfit heterostructure.
Superconductivity (cond-mat.supr-con)
13 pages, 4 figures
Conformal soft modes at elastic instabilities
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Lars Franke, Nick Sander, Markus Garst
In case a crystal is close to a continuous elastic phase transition, pronounced critical fluctuations emerge. We show that on the level of linear elasticity theory the displacement vector for these critical modes obeys a condition reminiscent of the conformal Killing equation. For an isostructural instability, four critical modes arise corresponding to one dilation and three special conformal transformations. At crystal symmetry-breaking instabilities, the critical fluctuations include a continuum of modes even for crystals with finite size. For certain cases, these comprise the conformal transformations associated with two-dimensional Minkowski space. These results have implications for critical elastic phenomena as well as for extremal mechanical metamaterials.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 2 figures
WannierSTM: Efficient superconducting scanning-probe spectroscopy from maximally localized Wannier functions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Oscar Moreno Segura, Dorye L. Esteras, Andrei Shumilin, Gonzalo Rivero-Carracedo, Riku Tuovinen, José J. Baldoví
We present a Python-based program that combines maximally localized Wannier functions-based first-principles electronic structure with the nonequilibrium Green’s function formalism to enable efficient simulations of scanning tunneling microscopy (STM). The workflow builds upon standard density functional theory packages to construct compact transport Hamiltonians that preserve the properties of realistic materials. Superconductivity is incorporated via an effective pairing potential within the Nambu-spinor formalism, while coupling to the STM tip and substrate electrodes is treated using the wide-band limit approximation. Within this formulation, transport quantities such as current-voltage characteristics and differential conductance are evaluated in a closed analytical form. This avoids explicit numerical energy integrations and enables rapid spectroscopic calculations over broad parameter spaces. The framework provides a unified and computationally efficient approach for modeling superconducting hybrid nanostructures with spin-orbit coupling, magnetic textures, and spin polarization. Representative applications in spin chains, two-dimensional and molecular magnets on a superconductor demonstrate its robust capabilities for both simple model systems and realistic ab initio molecular structures relevant to modern STM experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
23 pages, 9 figures
Thermal stability and structural ordering of thick Co$_2$MnAl films grown on MgO and Si substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
David Robles-Cuenca, Juan Antonio González, Juan Pedro Andrés, Miguel Ángel Arranz, Mohamed Salaheldeen, Ricardo López Antón
While most studies on Co$ 2$ MnAl (CMA) focus on the ultrathin regime for spintronic junctions, applications scaling with magnetic volume–such as Anomalous Nernst Effect (ANE) energy harvesters, integrated power inductors, and magnetic MEMS–require significantly thicker films. In this work, 750 nm thick CMA films were grown on MgO (001) and Si substrates to establish a roadmap for their thermal integration. Structural analysis reveals that B2 ordering is optimized on MgO at 600 $ ^\circ$ C, which is important for functional devices. In contrast, samples on Si substrates exhibit a disorder transition toward the A2 phase, closely linked to diffusion-driven degradation processes. Above 500 $ ^\circ$ C, Si interdiffusion into the Heusler layer triggers the formation of interfacial silicides and Kirkendall voids, leading to microcracking, electrical resistivity jumps, and a final fully disordered A2 phase. Despite the Mn-poor stoichiometry (Co$ 2.25$ Mn$ 0.7$ Al$ 1.05$ ), the films maintain a robust saturation magnetization of ~600 emu/cm$ ^3$ , consistent with recent theoretical models for off-stoichiometric Heusler alloys. These results define the processing windows for integrating thick CMA layers into multifunctional CMOS-compatible platforms.
Materials Science (cond-mat.mtrl-sci)
Published paper. 16 pages, 10 figures
Journal of Alloys and Compounds 1079 (2026) 189914
Field-free Magnetoacoustic Nonreciprocity via Exchange-bias Engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Weiqi Du, Mingyuan Ma, Zheng Sun, Chong Chen, Shixuan Liang, Deqi Tao, Shihai An, Yifan Fu, Sulei Fu, Feng Pan, Cheng Song
Nonreciprocal wave propagation is essential for directional signal processing and isolation. Magnetoacoustic systems are attractive platforms for nonreciprocal devices because of their small footprint and passive operation. However, pronounced nonreciprocity typically requires an external bias field,limiting device miniaturization and integration. Here, we demonstrate field-free magnetoacoustic nonreciprocity in an IrMn/FeGaB/Cu/FeGaB multilayer integrated with a shear-horizontal-wave delay line. Exchange-bias engineering stabilizes a remanent magnetic state with broken time-reversal and spatial-inversion symmetries while tailoring the spin-wave dispersion to achieve resonant magnetoacoustic coupling at zero field. The normalized isolation reaches 21 dB/mm, with its sign programmable by the field-sweep history. Further numerical optimization predicts a zero-field normalized isolation of 91 dB/mm by increasing the dynamical magnetic asymmetry. Our work establishes exchange-bias engineering as a promising route toward compact RF isolators and circulators and as a general strategy for realizing magnetoacoustic devices without external magnetic fields.
Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Direct view of exciton and carrier dynamics in twisted bilayer graphene
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Gianmarco Gatti, Anders S. Mortensen, Zhihao Jiang, Alfred J. H. Jones, Gesa-R. Siemann, Thomas S. Nielsen, Søren Ulstrup, Naina Kushwaha, Bruce Weaver, Yu Zhang, Emma Springate, Charlotte E. Sanders, Vibha Reddy, Ulrich Starke, Philip Hofmann
Twisted bilayer graphene (tBLG) on H-intercalated SiC (twist angle of $ 9 \pm 1^{\circ}$ ) is studied by position\mbox{-}, time\mbox{-}, and angle-resolved photoemission spectroscopy (ARPES). Both graphene layers are hole doped, with a Dirac-point offset of 30~meV. Time-resolved ARPES near the van Hove singularity reveals a spectral feature within the hybridization-induced band gap, together with excited electrons in the conduction band. The in-gap feature exhibits distinct dynamics, and its binding energy and $ k$ -space location are consistent with the proposed non-hydrogenic ``ghost-Fano’’ exciton arising from destructive interference between two nearly degenerate excitonic channels. Near the Dirac points, the twist separates the largely layer-polarized Dirac cones in momentum space, providing direct layer selectivity. We find markedly different peak electronic temperatures in the two graphene layers, even though their subsequent cooling dynamics are very similar. We attribute this to an ultrafast interlayer redistribution of electronic energy, driven by an interlayer electric field that arises from the different doping in the layers.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Knowledge-Guided Construction of Machine Learning Potentials for Reactive Behavior in Energetic Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Guanchen Dong, Huanrong Liu, Lin Wang, Yuxuan Chen, Zhengyu Tu, Qing-an Li, Bin Xu, Jian Li, Shan Zhang, Xiaotong Li, Linghua Tan, Guangcheng Yang, Jun Kang, Rui Su, Pengfei Guan
Energetic materials involve multiple interactions, making reliable machine-learning potentials (MLPs) difficult to construct without extensive datasets. Here, we enhance the ability of the neural network interatomic potential (NNAP) to describe molecular systems using sphmulti, a refined spherical-harmonic basis set that combines extra radial basis with element-specific chemical weighting in each radial channel. We further integrate hyperactive learning, farthest-point sampling, and iterative sufficiency criteria with knowledge-guided key events, enabling the NNAP to retain essential information for describing the material system. For 3,3’-diamino-4,4’-azoxyfurazan, the resulting NNAP is trained on only 13,680 configurations yet captures key properties, including the isomerization barrier, pyrolysis activation energy, and shock Hugoniot behavior. NNAP-driven molecular dynamics simulations further reveal that pyrolysis proceeds through furazan-ring opening followed by chain reactions, whereas shock loading induces anisotropic hydrogen transfer driven by interlayer structural deformations. This work enables efficient and reliable MLPs for energetic materials.
Materials Science (cond-mat.mtrl-sci)
Hydrogen partial pressure as a key parameter in the reactive sputtering of photochromic YHO thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
E. Strods, M. Zubkins, E. Letko, V. Vibornijs, A. Sarakovskis, J. Purans
Oxygen-containing yttrium hydride (YHO) thin films were synthesised by reactive magnetron sputtering over a wide range of hydrogen-to-argon gas flow ratios (H2/Ar) during yttrium hydride deposition, followed by post-oxidation in air. The deposition process was monitored in situ by plasma optical emission spectroscopy. X-ray diffraction reveals a strong dependence of crystallographic texture on the H2/Ar ratio: highly <100>-textured films formed at low H2/Ar ratios progressively evolve into more polycrystalline microstructures with slightly reduced crystallite size as the hydrogen content increases. The optical transmittance gradually decreases from approximately 85 % to 70 % as the H2/Ar ratio is raised to 0.6, followed by a sharp drop at higher hydrogen contents. The photochromic contrast of 690-820 nm thick YHO films, measured after 10 min of illumination with a solar simulator, decreases from 14 % to 7 % as the H2/Ar ratio increases from 0.08 to 0.60. Thinner films (360-490 nm) exhibit a similar but less pronounced trend. Bleaching kinetics, analysed using a double-exponential model, indicate faster recovery, with effective bleaching time constants of approximately 1-15 min for films deposited at H2/Ar < 0.25. X-ray photoelectron spectroscopy reveals higher oxygen incorporation in films deposited at lower H2/Ar ratios, deviating from the commonly reported correlation between oxygen content and photochromic response in YHO. These results demonstrate that low hydrogen partial pressure during reactive sputtering is advantageous for achieving higher optical transparency, enhanced photochromic contrast, and faster bleaching kinetics in YHO thin films.
Materials Science (cond-mat.mtrl-sci)
25 pages, 5 figures
Solar Energy Materials & Solar Cells 307 (2026) 114664
Evolution of dense liquid marbles under light tapping
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Amaelle Sprocq, Théo Dhoudain, Alexis Duchesne, Guillaume Lagubeau
Liquid marbles interface is composed by a dense network of grains trapped by capillarity at their surface. The mix of capillarity and granular character make their interfaces remarkable, allowing non wetting, high mobility and strong robustness which are a basis for numerous applications. A canonical experiment showing out of equilibrium nature of granular material is the so called tapping experiment, where a dry granular medium under vertical vibration reorganize an evolve toward a denser final state function of the vibration amplitude In this paper we explore the out of equilibrium nature of densely covered liquid marbles by measuring their shape, compaction and stresses evolution under vertical vibration. We show that liquid marble do indeed reorganize when submitted to taps, leading to higher internal pressure and lower effective surface tension.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Tellurium trioxide as an n-type wide-gap semiconductor with ultrahigh work functions from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Tianwei Wang, Teruya Nagafuji, Kota Hanzawa, Hidenori Hiramatsu, Fumiyasu Oba
The exploration of next-generation wide-gap semiconductors with extreme work functions is highly desirable for the continued advancement of electronic and optoelectronic devices. By using first principles calculations, we show that \b{eta}-TeO3, with a wide band gap exceeding 3 eV, emerges as a promising n-type semiconductor exhibiting ultrahigh work functions of up to ~8 eV. Intentionally or unintentionally incorporated interstitial H, Li, Na, Cu, Mg, and Zn impurities and substitutional F impurities are identified as shallow donors, whereas O vacancies act as minor carrier-compensating defects that locally trap electrons at neighbouring Te sites. The work function is evaluated across a series of low-index nonpolar surfaces. The presence of ordered O vacancies is energetically favoured on these surfaces and tends to reduce the corresponding work functions. These findings underscore the significance of precise control over the O chemical potential to suppress surface O-vacancy formation, thereby preserving the exceptional electronic performance of \b{eta}-TeO3 associated with ultrahigh work functions. Collectively, the results highlight the potential of \b{eta}-TeO3 for hole injection/extraction/transport layers as well as transparent electrodes for applications such as light-emitting devices and photovoltaic cells, while providing useful guidance on carrier doping and surface tuning for these practical applications through elucidating the effects of the point-defect and surface configurations on the electronic properties.
Materials Science (cond-mat.mtrl-sci)
Organisation and aggregation of calcium carbonate ions in water via molecular simulation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Elizaveta Sidler, Rita S Dias, Raffaela Cabriolu
Crystallisation of calcium carbonate (CaCO$ _3$ ) in aqueous solutions is essential for carbon dioxide sequestration and the sustainable production of calcium carbonate materials, which are widely used in industry and increasingly explored for novel applications. While crystallisation is often analysed within the framework of classical nucleation theory, CaCO$ _3$ and other ionic crystals often form through amorphous precursor phases, motivating the need for alternative descriptions. In this work, we investigate the relationship between the formation of the first CaCO$ _3$ coordination sphere, a fundamental unit of local ordering, and ionic aggregation using two complementary simulation approaches: on-the-fly probability-enhanced sampling (OPES) and asynchronous and infinite-swap replica exchange transition interface sampling ($ \infty$ RETIS). OPES was used to explore free-energy landscapes, whereas $ \infty$ RETIS was used to determine reaction kinetics. We studied systems at two levels of supersaturation, between which the formation of the first coordination sphere exhibited distinct kinetic behaviour. These differences were found to be linked to concentration-dependent ionic aggregation. At lower concentration, aggregation remains limited, whereas higher concentration promotes extensive spinodal-like aggregation. For both concentrations, the first coordination sphere forms within the pre-formed clusters through one of two distinct pathways: either within a cluster close to the minimum size required for its formation, or within larger amorphous aggregates whose size and structure depend on concentration. The coexistence of these pathways at both levels of supersaturation reveals the multifaceted nature of early-stage CaCO$ _3$ crystallisation and highlights the importance of differentiating ionic aggregation and organisation.
Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Local-resolvent formulation and assessment of linear-scaling Kohn-Sham calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Kohn-Sham density-functional theory is expensive because it needs orbitals that extend over the whole system. For insulators this can be avoided by using only the diagonal of the one-electron resolvent, $ g(\mathbf{r},z)=\langle\mathbf{r}|(z-\hat h)^{-1}|\mathbf{r}\rangle$ , at a few complex energies $ z$ . We call the scheme local-resolvent density-functional theory (LRes-DFT). The density and the band energy are linear in $ g$ , so neither orbitals nor a kinetic-energy functional are needed. The complex energies are $ M$ equally spaced points on a circle that encloses the occupied levels, offset by half a spacing so that no point lies on the real axis. Summing the resolvent over them is equivalent to occupying each level with $ 1/(1+u^M)$ , where $ u$ is the level’s energy measured from the circle’s center in units of its radius. This is a smooth step that is near 1 inside the circle and near 0 outside, and it stays between 0 and 1 for every $ M$ . If the circle moves with the chemical potential, forces at fixed electron number are exact. Gauss-Legendre and Zolotarev rules need fewer points when the gap is small. In three dimensions we use eigenpairs of small windows around each molecule instead of resolvents. This is divide-and-conquer (DC) with a different occupation function, and it is as accurate as DC with Fermi-Dirac occupations. For H$ _2$ molecular crystals of up to 1024 electrons it agrees with Kohn-Sham to $ 2.5\times10^{-7}$ Ha per electron. On one core it is slower than dense diagonalization below about 500 electrons and 3.5 times faster at 1024 electrons. It loses accuracy for disordered or compressed systems and for diffuse basis functions.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Effects of the choice of the exchange-correlation functional on high-temperature superconductivity predictions in covalent-cage M(BN)5 family
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Zhongyu Wan, Guo-Hua Zhong, Cheng-wei Ju, Ruiqin Zhang, Hai-Qing Lin
The recent experimental synthesis of covalent cage superconductors has ignited hopes for ambient-pressure high-temperature superconductivity, while the computational strategy for discovering new materials poses challenges for accurately estimating superconducting properties. Here, we quantified the response of electron-phonon coupling (EPC) properties in M(BN)5 superconductors to different exchange-correlation (XC) effects using high-throughput first-principles calculations. We found that the metallic covalent bonds responsible for superconductivity exhibit anomalously high sensitivity to functional selection uncertainty, distinguishing them from conventional superconductors mediated by metallic bonding. The widely used PBE functional systematically overestimates lattice volumes, inducing phonon softening, enhanced EPC, and consequent Peierls instability. In contrast, PBEsol, which is more accurate through enhanced treatment of short-range interactions, eliminates imaginary frequencies in Rb(BN)5 that appear at the PBE level, yielding an outstanding superconducting critical temperature (Tc) of 113 K at ambient pressure and 138 K at 2 GPa. Enhanced electron localization and short-range correlation in covalent bonds manifest through dual mechanisms: phonon hardening at the lattice scale and band widening at the electronic scale, which collectively suppress Peierls distortion and delocalize antibonding states. Pressure-dependent analysis reveals that compression attenuates phonon discrepancies between XC functionals, whereas electronic properties remain notably sensitive to XC-induced perturbations of fine electronic bands near the Fermi level.
Superconductivity (cond-mat.supr-con)
Non-Hermitian Statistical Geometry
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Xi Hu, Yan-Qiong Ma, Su-Peng Kou
Particle exchange in two dimensions gives rise to quantum statistics beyond the boson-fermion dichotomy, with central roles in fractional quantum Hall physics, topological quantum computation, and strongly correlated quantum matter. In conventional topological phases, microscopic exchange geometry is compressed into rigid braid and fusion data. We develop a theory of non-Hermitian statistical geometry in which relaxing Hermiticity softens these exchange data into a larger complex space of spectral and relative-geometric degrees of freedom. For two adjacent braid generators, a single projective exchange spectrum is insufficient: their relative eigenline geometry supplies an additional gauge-invariant modulus. On the generic irreducible two-channel branch, braid consistency locks these coordinates through an exact spectrum-geometry relation. Using Riesz projectors and Kato transport, we realize this geometry in a five-arm Kitaev-Majorana network and test spectral and relative-geometric responses in an independent two-dimensional four-vortex Kitaev model. Finite-time dynamics tests the exchange operation, microscopic fusion sewing tests its composition across fusion descriptions, and matched-spectrum controls isolate the role of relative geometry. Nonzero projective Kato curvature shows that braid-consistent, fusion-coherent exchange can depend on the control path. Non-Hermiticity thus exposes exchange geometry, braid consistency re-locks it, fusion coherence further constrains it, and projective flatness determines when geometric exchange becomes intrinsically topological.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
17 pages of main text, 34 pages of Supplemental Material; 12 figures in total
High-throughput screening of Heusler alloys for thermoelectrics combining machine-learned densities of states and first-principles transport
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Shivam Randive, Ayana Ghosh, Rahul Dixit, Himanshu Pandey
Thermoelectrics turn waste heat into electricity, but finding new ones requires transport calculations too costly for whole databases. Searches therefore choose what to calculate from the electronic density of states (DOS), increasingly predicted by machine learning, yet such choices are rarely tested. We test them on all 106,235 Heusler structures in the DXMag database, screening 51,257 on density-functional spectra and 54,978 on neural-network predictions, and judging both by 3,625 band-structure and transport calculations. A DOS-derived Seebeck indicator ranks most compounds passing every transport and stability test within the top 1% of their population, and ten of the eleven established half-Heusler thermoelectrics calculated pass. Predicted spectra lose most band gaps, unnoticed by spectral-similarity metrics, yet still rank passing compounds near the top. The screen certifies 80 computational candidates, 61 without reported measurements. Computed or predicted, the DOS can choose what to calculate; only a band structure shows whether a gap exists.
Materials Science (cond-mat.mtrl-sci)
21 pages, 10 figures, 3 tables; Supplementary Information (21 pages) included
Orientation-Resolved Nanoindentation of Single Crystal Ti-15Mo: Inverted Elastic Anisotropy and Yield-Onset Behavior Beyond Simple CRSS Predictions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Kidus Abebe, David Gaetano, Aurelia Moriyama-Gurish, Jana Šmilauerová, Yanfei Gao, Udo D. Schwarz, Amit Datye
Ti-15Mo (wt%) is a well-established $ \beta$ -stabilized alloy whose mechanical response is strongly governed by phase stability and deformation mechanisms that operate at the single-grain scale. Because these intragranular mechanisms are intrinsically anisotropic, understanding the orientation dependence of the elastic and plastic response is critical to the texture-engineered processing of wrought components. Here, we quantify the nanomechanical anisotropy of single-crystal Ti-15Mo by combining EBSD with nanoindentation to correlate hardness, indentation modulus, strain rate sensitivity, and indentation yield response with the crystallographic surface normal near $ \langle111\rangle,\langle124\rangle,\langle011\rangle,\langle023\rangle$ , and $ \langle013\rangle$ directions. While the modulus anisotropy is small (~10%), contrary to the prediction for a cubic crystal with A>1, orientations near $ \langle111\rangle$ exhibit the lowest moduli. Yield onset is likewise softest near $ \langle111\rangle$ and spans 41%, while hardness spans only 6.6% and follows neither the modulus nor the yield ordering. The alloy also exhibits yield behavior not captured by the simple CRSS/Schmid-factor models evaluated here. Strain-rate-jump tests yield V\ast=18-31b$ ^3$ , consistent with kink-pair-nucleation-controlled plasticity; based on V\ast, the orientations separate into two groups suggestive of glide-dominated versus twin/transformation-participating response. We reveal an inversion of the elastic anisotropy expected for a homogeneous cubic $ \beta$ -phase and an orientation-dependent yield-onset response that is not reproduced by the simple Schmid-factor models examined here. Retained athermal $ \omega$ is proposed as the contributor because $ \beta\rightarrow\omega$ collapse occurs on {111}$ _\beta$ planes and may provide anelastic compliance through the reversible $ \omega\rightarrow\beta$ transformation.
Materials Science (cond-mat.mtrl-sci)
26 pages, 6 figures
Quantitative Impact of Occupation Smearing Methods on Conventional Superconductivity: from Electronic Structure through Lattice Dynamics to Electron-Phonon Coupling
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
In first-principles calculations of metallic systems, the discrete electronic mesh in the Brillouin zone necessitates a smearing function and its width (e.g., the widely used 0.02 Ry Methfessel-Paxton scheme) to enforce continuity of energy and occupation at the Fermi surface. However, the quantitative impact of such empirical parameters on phonon-mediated superconductivity has long been overlooked, leading to their habitual selection by mere convention. Here, using hexahydride CsH6 as a benchmark, we systematically investigate the magnitude and propagation mechanism of smearing-induced errors against the parameter-free optimized tetrahedron method. Long-tailed smearing delocalizes the occupation window, causing substantial Fermi-level shifts, flattening of the density of states, and hardening phonon modes, thereby weakening electron-phonon coupling. Conversely, short-tailed smearing suffers from insufficient sampling, producing density-of-states oscillations and enhanced Fermi-surface nesting; via amplified electronic screening and Peierls instabilities, this softens acoustic modes and generates imaginary frequencies, causing CsH6 to be dynamically unstable and discarded. However, the optimized tetrahedron method reveals that CsH6 is dynamically stable under ambient pressure with a remarkable superconducting transition temperature of 121 K. To prevent subjective empirical parameters from obscuring theoretically promising high-temperature superconductors, we derive a simple scaling relation for the smearing width, applicable to different smearing functions, from the free-electron-gas model, offering an objective, precise, and efficient protocol for parameter selection in high-throughput screening.
Superconductivity (cond-mat.supr-con)
Unexpected stabilization of a single-$q$ charge density wave in pristine 1T-TiSe$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Kimoon Higashihira Han, Dongju Hwang, Dongsin Kim, Yeojin Ahn, Jaehun Cha, Seonggeon Gim, Gyubin Lee, Mingi Jho, Chan-young Lim, Sae Hee Ryu, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Jonathan D. Denlinger, Makoto Hashimoto, Donghui Lu, Young Woo Choi, Gil Young Cho, Yeongkwan Kim
Over the past decade, studies revisiting the classical charge-density-wave system 1T-TiSe$ _2$ , long understood to host the $ 2 \times 2$ triple-$ q$ order with equivalent subcomponents, have suggested that these subcomponents may not be identical, challenging a 50-year-old paradigm. Here, we demonstrate not only that these subcomponents are non-identical but also that they develop sequentially rather than simultaneously. By tracking folded-band features, angle-resolved photoemission spectroscopy reveals that a unidirectional $ 2 \times 1$ single-$ q$ order stabilizes first, while the other two components emerge sequentially at lower temperatures, completing the triple-$ q$ phase. Our free-energy analysis explains this hierarchy through repulsive coupling among the three subcomponents, as supported by first-principles calculations incorporating phonon anharmonicity. Consequently, the three subcomponents are inequivalent in both phase and amplitude. These results reconcile reported symmetry breaking and differing characteristic temperatures and establish a framework in which ostensibly simple, high-symmetry charge-density order emerges from temperature-dependent competition and cooperation among inequivalent subcomponents.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
21 pages, 4 figures. Accepted for publication in Nature Communications. Supplementary Information is not included in this arXiv version and is available with the published article at this https URL
MINFF: A Family of Classical Force Fields for Minerals with Tunable Angle Terms
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Michael Holmboe, Nathan Lavauzelle, Rogers E. Swai
Atomistic simulations of minerals are limited by the accuracy and transferability of the force field. We introduce MINFF, a force field family for layered and non-layered oxides and hydroxides of M being Si, Al, Fe, Mg, Ca, Ti, Li and F. MINFF has no M-O bond terms. Instead M-O distances follow from electrostatics and dispersion, while a single harmonic angle term on all M-O triplets controls coordination geometry. Metal charges are DDEC6 charges from reference mineral structures, and oxygen charges are assigned by nearest-neighbour charge smearing, covering basal, apical, hydroxyl and edge sites and sites adjacent to isomorphous substitutions. The oxygen Lennard-Jones parameters are based on the OPC3 water model and change by less than 5% when re-optimised per mineral, so compatibility with OPC3 and related ion-pair potentials is measured rather than assumed. Metal Lennard-Jones parameters were fitted to unit-cell metrics, bond distances and angles, both synchronously across more than 30 reference minerals (general, GMINFF) and for individual minerals (tailored, TMINFF), each at four angle force constants (0, 250, 500 and 1500 kJ/mol/rad^2). With angle terms, MINFF reproduces experimental unit-cells metrics to within 0.5% and atom-type distances and angles to within 0.7-1.4% and 0.1-0.4%, with Global Instability Index values as low as 0.11, below those of CLAYFF (0.34) and INTERFACE (0.21). A moderate angle constant reproduces the stiff in-plane and soft shear elastic constants of phyllosilicates and improves the Kaolinite librational bands, and in hydrated Na-Montmorillonite MINFF gives the lowest residual factor against the 2W 00l pattern of the models tested. The general and tailored sets at four angle stiffnesses give direct control over the transferability-fidelity trade-off. Topologies can be generated with the atom (MATLAB) and atomipy (Python) libraries and at this http URL.
Materials Science (cond-mat.mtrl-sci)
63 pages, 7 figures and 3 tables in the main text. Supporting information (included in the same file) has 19 pages with 9 figures and 5 tables. Parameters, reference structures, misc. scripts and topology generators available via this https URL and this https URL
Zeeman spin quantum geometry and intrinsic gyrotropic spin current
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Srijan Chatterjee, Tarun Kanti Ghosh
We uncover an intrinsic gyrotropic spin current (IGSC) driven solely by an oscillating magnetic field, arising from the spin version of Zeeman quantum geometry. Using the density matrix formalism, we derive the IGSC in the low-frequency clean limit, in terms of the Zeeman spin quantum metric and the Zeeman spin Berry curvature. The effect is studied in a minimal Rashba-Dresselhaus model that also supports intrinsic gyrotropic charge currents from the Zeeman Berry curvature. The spin and charge currents exhibit a $ \pi/2$ phase shift and are found to be perpendicular to each other for certain parameter ranges. This not only enables spin current detection but also opens pure spin current channels for energy-efficient spintronics. We further observe that these currents switch directions between longitudinal and transverse relative to the applied field, depending on the relative strength of Rashba and Dresselhaus interactions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 3 figures
Molecular-Dynamics Verification of Effective Gravity under Heat Conduction
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
We test the effective-gravity prediction of global thermodynamics using standard molecular dynamics of a two-dimensional Lennard-Jones fluid. Under weak heat conduction with the lower boundary hotter than the upper boundary, the transition between liquid below gas and liquid above gas shifts from zero to finite downward gravity. Using independently measured equilibrium saturation pressures, we calculate the shift predicted by global thermodynamics and find agreement with the observed transition shift. The transition occurs at zero effective gravity, where the hydrostatic pressure difference balances the saturation-pressure difference between the two boundaries. The hysteresis response under heat conduction also agrees with the equilibrium response when plotted against effective gravity. These results establish the predictive power of global thermodynamics for nonequilibrium structure formation.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 5 figures. Two supplemental movies are provided as ancillary files
Coherent Phonon Generation from Prethermal Carrier Populations in a Semiconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Mingyu Shi, Matteo Savoini, Patrick Friebel, Andrea Annunziata, Thomas Metzger, Yunpei Deng, Laura Cattaneo, Steven L. Johnson
Ultrafast laser excitation of carriers in semiconductors often results in the creation of fully symmetric coherent optical phonons, typically understood in terms of a thermalized transient carrier population. We test this understanding with systematic measurements and first-principles calculations of the photon-energy dependence of ultrafast-laser-driven coherent phonon generation in tellurium, using excitation wavelengths around the electronic band gap. We observe that, contrary to the expectations of models assuming a thermalized carrier population, the coherent amplitude of the fully symmetric $ A_1$ mode changes only weakly when tuning wavelength across the band gap. The measured spectral dependence is instead reproduced by a transition-resolved prethermal force weighted by optical matrix elements and band- and momentum-dependent $ A_1$ deformation potentials. Fitting this model to the data yields an excited transition state lifetime of a few femtoseconds. These results identify transition selectivity, rather than a thermalized total carrier density, as a key factor controlling coherent-phonon generation in semiconductors excited near a band gap.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures; Supplemental Material: 22 pages, 9 figures, appended
Phonon-Mediated Superconductivity near Phase Boundaries in Rhombohedral Multilayer Graphene
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Konstantinos Sourounis, Peter M. Oppeneer
The recent observation of superconductivity in untwisted multilayer graphene has sparked intense interest in its microscopic origin. As the displacement field and carrier density are varied, superconductivity emerges in several distinct regions with different temperature and magnetic-field responses. This behavior has been attributed to the presence of distinct electronic phases, raising the possibility that different superconducting regions originate from different microscopic mechanisms. While purely electronic pairing mechanisms have been extensively explored, an in-depth examination of phonon-mediated superconductivity is still missing. Here, we solve the coupled selfconsistent Migdal-Eliashberg equations using input from first-principles calculations and incorporating interaction-driven symmetry breaking of the electronic ground state. Varying the carrier density and displacement field, we reproduce the experimentally observed superconducting regions with comparable superconducting properties such as gap and $ T_c$ and predict additional, as-yet undiscovered superconducting phases. Our findings exemplify that several superconductivity regions in rhombohedral graphene can be satisfactorily explained by phonon-mediated pairing.
Superconductivity (cond-mat.supr-con)
15 pages, 11 figures
Role of dissipation dilution in achieving high mechanical quality factors in van der Waals resonators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Lukas Schleicher, Leonard Geilen, Alexander Musta, Niklas Walter, Anne Rodriguez, Philipp Bredol, Alexander W. Holleitner, Eva M. Weig
Dissipation dilution has driven a revolution in the quality factors ($ Q$ ) of top-down nanomechanical resonators. Yet it has not been leveraged for van der Waals (vdW) materials. Here we report quality factors up to $ 372{,}000\pm37{,}000$ in monolayer MoS$ _2$ drums at 4 K, nearly an order of magnitude beyond the previous best for any vdW material at this temperature, enabled by a clean, polymer-free exfoliation technique. We develop a dissipation-dilution model for circular drums and analyze the contributing intrinsic and extrinsic dissipation mechanisms. The MoS$ _2$ monolayer exhibits a dilution factor of order $ 1,000$ , establishing sub-nanometer-thin resonators as ultimate dilution materials. The intrinsic quality factor, however, is limited by surface losses at atomic thickness. Conversely, multilayer drums show a lower dilution factor but a high intrinsic quality factor, on par with established top-down materials of similar dimensions, both resulting from the increased thickness. A two-level-system analysis of the temperature-dependent damping confirms this bulk-versus-surface picture and provides first insight into its microscopic origin. Our results identify dissipation dilution as the governing mechanism for high-$ Q$ mechanical vdW resonators. Combined with strategies such as soft clamping or stress engineering, they establish atomically thin resonators as a platform for ultrahigh-$ Q$ quantum transduction and sensing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
A Topological Spin on Racetrack Memory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Magnetic racetrack memory requires localized carriers that combine rapid motion, resistance to perturbations and a detectable signal. Here we show how a 360° domain wall in a hollow ferromagnetic tube combines these properties within a single continuous magnetic shell. Two successive magnetization reversals form a bound object whose surrounding domains point in the same direction. Analytical energetics and micromagnetic simulations establish its finite separation, recovery from tested perturbations and current driven transport without microscopic Dzyaloshinskii-Moriya interaction or a maintaining field. The texture’s winding resists unwinding while radial rotation carries an energy cost, providing a specific control over stability. Relative rotation of the constituent spins accounts quantitatively for additional displacement during current onset. The wall supports motion at hundreds of metres per second, with transient velocities approaching one kilometre per second at stronger drive. A prepared seven-bit pattern retains its carriers and local readout contrast after pulsed transport and recovery. Curved-track and differential-current tests identify radial stiffness and drive uniformity as controls for intact motion. These results establish a physical basis for fast, locally distinguishable tubular magnetic bits and identify a continuous switching pathway that can be targeted by tailored excitation.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
Transition-Metal-Induced Uniaxial Anisotropy in YFe$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
M. Nur Hasan, Bruno L. Fertig, Santa Pile, Rafael M. Vieira, Alena Vishina, Alexander Kovacs, Gotthard Rieger, Stefan Denneler, Samuel J. R. Holt, Martin Lang, Swapneel Pathak, Andrea Petrocchi, Hans Fangohr, Thomas George Woodcock, Thomas Schrefl, Heike C. Herper
Achieving uniaxial magnetocrystalline anisotropy while preserving high magnetization and thermal stability remains a central challenge in the development of Fe-rich permanent magnets. YFe$ _3$ is a promising candidate owing to its saturation magnetization and Curie temperature, but its intrinsic easy-plane anisotropy limits its potential for permanent-magnet applications. Here, we show that selective transition-metal substitution drives an easy-plane-to-easy-axis transition in YFe$ _3$ . Systematic first-principles screening identifies V, Nb, and Ta as effective dopants, with YFe$ _{2.33}$ Ta$ _{0.67}$ exhibiting a large uniaxial magnetocrystalline anisotropy energy of 2.3MJ/m$ ^{3}$ . Calculated exchange interactions and atomistic Monte Carlo simulations show that the enhanced anisotropy is achieved while preserving robust ferromagnetic order and high thermal stability. Micromagnetic simulations further reveal that YFe$ _{2.33}$ Ta$ _{0.67}$ exhibits the highest coercivity and strongest resistance to irreversible demagnetization, whereas YFe$ _{2.33}$ V$ _{0.67}$ achieves a comparable maximum energy product at 300K. Experimental characterization of V-alloyed YFe$ _3$ shows that the YFe$ _3$ phase can be retained at low nominal V concentrations (1-3 at.%) under the employed synthesis and heat-treatment conditions, whereas higher V contents lead to increasingly multiphase samples. Concentration-dependent MAE calculations reveal a sign reversal between approximately 11 and 14~at.% V, marking the transition from easy-plane to uniaxial easy-axis anisotropy. Consistent with this concentration dependence, electron backscatter diffraction and Kerr microscopy reveal in-plane magnetic domain structures in the experimentally accessible low-V regime. Therefore, our work offers a promising approach to tuning the magnetocrystalline anisotropy of YFe$ _3$ while retaining high Curie temperatures.
Materials Science (cond-mat.mtrl-sci)
21 pages, 11 figures and Supplementary Information
Accurately Generalizing Deep-Learning Hamiltonian Methods to Plane-Wave Density Functional Theory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Chuntian Wu, Jiaxiang Li, Qiang Xu, Xuecheng Shao, Congwei Xie, Yu Xie, Yanming Ma
Deep neural networks that predict density functional theory (DFT) Hamiltonians from material structures offer a route to efficient electronic-structure calculations. However, extending localized atomic-orbital (AO) Hamiltonian learning to plane-wave (PW) calculations with hybrid functionals requires a compact AO representation that preserves the effects of nonlocal operators. Here we propose a projectability-guided construction of nonorthogonal AO Hamiltonians from a small, selected set of PW eigenstates and eigenvalues. High-projectability states are retained, and selected higher-energy states complete the AO subspace, avoiding an empirical shift and its arbitrary contribution to the learning targets. Because the construction uses PW eigenstates and eigenvalues, it incorporates nonlocal contributions present in the reference calculation without explicitly reconstructing their AO matrix elements. Benchmarks for MoS2 and sodium phases show accurate reproduction of PW bands with smaller AO bases than real-space reconstruction. The resulting PBE and HSE Hamiltonians can be learned by equivariant neural networks, connecting PW reference calculations with electronic-structure prediction. This approach broadens the range of PW DFT calculations available for AO Hamiltonian learning and enables compact, accurate training targets for developing more widely applicable electronic-structure models.
Materials Science (cond-mat.mtrl-sci)
Charge-selective topological locking and ultraslow coarsening in magnetoelastic media
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Tirthankar Banerjee, Amaresh Jaiswal
We demonstrate that the symmetry of magnetoelastic coupling governs the topological organization of composite defects and can qualitatively alter phase-ordering kinetics. In a two-dimensional theory of an in-plane magnetic vector coupled to elastic strain, we find that integer magnetic vortices bind pairs of elementary elastic half-defects. Isotropic magnetostriction produces a core-induced elastic winding independent of the magnetic charge, giving defect binding without charge locking and leaving the magnetic sector with essentially XY-like coarsening. In contrast, quadrupolar magnetoelastic coupling locks magnetic and elastic defect charges: continuous rotational symmetry favors $ q_\phi=q_\theta$ , whereas crystalline anisotropy can reverse the locking to $ q_\phi=-q_\theta$ . We reveal that both locking sectors display anomalously slow vortex annihilation: defect density shows a power-law decay $ t^{-2/5}$ , while the average defect-velocity scales as $ t^{-4/5}$ . These results are consistent with a dynamic exponent $ z\simeq 5$ . We show that this coarsening slowdown is associated with large anisotropic elastic friction. An adiabatic elimination of the elastic field reveals that isotropic magnetostriction merely renormalizes local magnetic interactions, whereas orientational coupling induces effective nonlocal interactions between magnetic spins. Our experimentally testable results thus establish magnetoelastic coupling symmetry as a means of controlling defect topology and ordering kinetics.
Statistical Mechanics (cond-mat.stat-mech)
7 pages + 3 figures (main text), and 14 pages + 2 movies (supplemental material)
Ionic gradients shape the spatial organization and dynamics of supramolecular polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
Claudio Perego, Annalisa Cardellini, Andrea Tagliabue, Giovanni M. Pavan
Living supramolecular materials such as microtubules and actin filaments assemble and function in dynamic, heterogeneous environments, subject to chemical concentration gradients. Their rapid and precise response to such gradients—via aggregation, disassembly, or autonomous motion—underlies the fine spatiotemporal control typical of living systems. Reproducing such responsiveness in synthetic materials is a central challenge in materials science and requires a molecular-level understanding of how gradients couple to supramolecular structure and dynamics, which remains difficult to access experimentally. To this end, we combine implicit-solvent coarse-grained molecular dynamics (MD) with the constant chemical potential MD (C$ {\mu}$ MD) technique to investigate, at molecular resolution, the coupling of two prototypical supramolecular polymer models with externally imposed ionic concentration gradients. Despite their contrasting responses to homogeneous ionic conditions, both systems undergo pronounced spatial reorganization under the gradient, generating regions of locally enhanced supramolecular activity that are inaccessible to homogeneous systems with the same overall content of self-assembling species. Crucially, the local supramolecular dynamics is largely determined by the local concentrations, consistent with the formation of local quasi-equilibria: this direct connection between spatial composition and supramolecular activity emerges as a common governing principle across the two models. These findings shed light on the spatially complex supramolecular response that can be triggered by chemical gradients, and show how a single gradient simulation can encode this response across a continuous range of local chemical environments, thus providing a general strategy to investigate and design materials operating under spatially heterogeneous conditions.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
30 pages, 5 Figures + SI: 5 pages, 3 figures
Reversible Magneto-ionic Modification of Metallic Magnetic Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Md Golam Hafiz, Hari Babu Vasili, Philippa Shepley, Mannan Ali, Andrew J. Britton, Oscar Cespedes, Weibin Li, Manuel Valvidares, Rohit Pachat, Wilfried Fotso, Mourad Cherif, Shimpei Ono, Yves Roussigne, Mohamed Belmeguenai, Gavin Burnell
Magnetic multilayers with structural inversion asymmetry, perpendicular magnetic anisotropy (PMA), and large Dzyaloshinskii-Moriya interaction (DMI) are widely studied for magnetic domain wall- and skyrmion-based data processing applications. In this work, we report a controlled, nonvolatile, but reversible local modification of such a system by electrically driven oxygen migration through the metallic film structure by using ionic liquid gating. Our findings provide direct evidence for the modification of the oxidation state at the heavy metal (HM)/ferromagnet (FM) interface. As a result, we observed changes in fundamental magnetic properties, such as an increase in the effective anisotropy constant (Keff) and coercive field (Hc) with oxidation, and a decrease with the reduction of oxygen ions. Positive gate voltages relative to the thin film extract oxygen ions from the magnetic layer, significantly reducing the domain nucleation field. In contrast, negative voltages drive oxygen ions into the magnetic layer, leading to a reversible increase in the extent of domain wall pinning near saturation. We observe a corresponding decrease in the magnetic moment and DMI, with negative voltage reducing both. This magneto-ionic modulation in fully metallic structures is beneficial for spintronic device applications, particularly in field-programmable domain wall and skyrmion devices.
Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures
ACS applied Electronic materials, 14 April 2026, 8, 7, 3198 - 3206
Curie-Weiss cell fluid model: Fitting to experimental critical-point data
New Submission | Soft Condensed Matter (cond-mat.soft) | 2026-10-14 20:00 EDT
I.V. Pylyuk, O.A. Dobush, M.P. Kozlovskii, R.V. Romanik, M.A. Shpot
We examine how the Curie–Weiss cell fluid model can be quantitatively related to real fluids by determining its microscopic parameters from experimental critical-point data for water, carbon dioxide, and three polyol ester lubricants (POE5, POE7, and POE9). The microscopic parameters of the model are determined from the experimental values of the critical temperature and critical density: the global attraction coupling constant is fixed by the critical temperature, and the cell volume by the critical density. The critical pressure then follows as an independent model prediction, deviating from experimental values by 10–41$ %$ across the studied substances. Varying the ratio of local repulsion to global attraction $ f=J_2/J_1$ over a wide range has only a weak effect on this deviation. For $ f\geq1$ , the model’s critical compressibility factor lays within a narrow range $ Z_c\approx0.382-0.386$ , remaining close to the mean-field van der Waals value $ Z_c=3/8=0.375$ and consistently overestimating experimental values. The best agreement with experiment is obtained for the polyol ester lubricants and improves along the POE5–POE7–POE9 series with increasing molar mass, suggesting that multiple-occupancy cell fluid models are well suited to systems of large molecules, particularly soft-matter systems with bounded interaction potentials. We further show that generalizing the model by introducing a temperature- and phase-dependent effective attraction allows it to describe a triple point and to reproduce the broad range of critical-to-triple temperature ratios $ T_c/T_{\mathrm{tr}}$ characteristic of real fluids.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
14 pages, 1 figure
The role of dependency range in thermally coupled superconducting networks
New Submission | Superconductivity (cond-mat.supr-con) | 2026-10-14 20:00 EDT
Nahala Yadid, Bnaya Gross, Shlomo Havlin, Nadav M. Shnerb
Interdependent networks can be highly fragile because dependency links amplify local failures into cascades that trigger global collapse. Much of the theoretical understanding comes from geometric network models, where dependency range is imposed externally and coupling strength is distance independent, and it is unclear how these insights apply to real materials, where interdependence arises from physical transport. Here we study thermally coupled amorphous superconducting networks, in which dependencies emerge from current redistribution and heat-mediated interactions governed by thermal diffusivity. Using an experimentally calibrated model of resistively shunted Josephson junctions, we show the system reproduces the three canonical transition regimes: continuous, nucleation-dominated, and mixed-order. However, because heat-driven dependency simultaneously broadens and weakens with distance, long-range thermal coupling can stabilize the superconducting phase upon heating, in contrast with its destabilizing role in geometric models. Cascades are anisotropic, with one-dimensional front propagation. These results offer an experimentally testable perspective complementing the geometric framework.
Superconductivity (cond-mat.supr-con)
Altermagnetic Ground States on the Ammann–Beenker Tiling
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
SeungBeom Hong, YunHo Kim, Moon Jip Park, GiBaik Sim
We identify exact altermagnetic ground states of a classical Heisenberg model on a quasicrystal. Considering the Ammann–Beenker tiling as an example, we determine the ground states by exploiting the parity structure of its parent four-dimensional hypercubic lattice. The ground state hosts coplanar altermagnetic order characterized by the preserved spin-group symmetry $ [C_{2x}\parallel C_{8z}]$ . Without translational symmetry, the momentum-space spin splitting that usually identifies altermagnets is not directly accessible. We instead couple the spins to itinerant electrons and show spin-resolved transport with $ g$ -wave symmetry, confirming the altermagnetic nature in a nonperiodic system. Our results establish a geometric route to altermagnetic order in quasicrystals, connecting exact magnetic ground states to their spin-resolved transport signatures.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 4 figures + Supplemental Material (14 pages, 6 figures)
Substrate-controlled epitaxial-like growth and photochromic properties of yttrium oxyhydride thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
M. Zubkins, E. Strods, E. Letko, H. Mändar, D. Moldarev, K. Mizohata, K. Sarakinos, V. Vibornijs, K. Kundzins, J. Purans
Yttrium oxyhydride (YHO) thin films are synthesised by reactive magnetron sputtering of \b{eta}-YHx precursor films onto single-crystalline yttria-stabilised zirconia (YSZ) (111) and (100) substrates at 200 °C, followed by post-deposition oxidation in air. For comparison, reference films are also prepared on amorphous SiO2 and soda-lime glass substrates at both 200 °C and room temperature (RT). The structural (X-ray diffraction and scanning electron microscopy), compositional (elastic recoil detection analysis), and optical properties, including photochromic behaviour, of the films are systematically investigated. The results reveal a strong influence of substrate orientation on the film microstructure and crystallographic texture, leading to epitaxial-like growth with a mosaic spread of 3-4°. YHO deposited on YSZ(100) exhibits larger crystallite sizes (10-20 nm) than YHO grown on YSZ(111) (8 nm) and exhibits residual in-plane compressive strain while remaining largely relaxed with respect to the substrate. Films deposited at 200 °C exhibit lower oxygen concentrations (O/Y = 0.71-0.82) than films deposited at RT (O/Y = 0.92-1.26). All films exhibit photochromic behaviour under solar simulator illumination, with relative transmittance changes ranging from 7 to 22 % after 10 min of illumination. Despite the pronounced structural differences, the epitaxial-like films show no systematic improvement in photochromic response, indicating that the effect is governed primarily by composition and the local O/H configuration rather than by long-range cation ordering. These findings provide new insights into the relationship between crystallographic texture, composition, and photochromic properties in YHO thin films, contributing to the understanding of this material for optical and optoelectronic applications.
Materials Science (cond-mat.mtrl-sci)
26 pages, 5 figures
Surface & Coatings Technology 540 (2026) 133981
Quantitative Modelling of Solvation in 2D Materials via Alchemical Decoupling and Potential Energy Surfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Lindsey N. Ioos, Duncan A. Peterson, Scott C. Warren
Understanding why 2D materials remain suspended in solutions is essential to understanding the mechanisms of aggregation and exfoliation. These dynamics have been difficult to model because of the long timescales and large activation energies involved in these simulations. Here we describe an improved strategy for modelling the solvation and stability of 2D materials that uses the Gibbs free energy of solvation to accurately calibrate two disconnected potential energy surfaces for the fully desolvated and fully solvated 2D materials. By joining these surfaces using solvation energy, we obtain predictions for 2D material stability in various solvents that are qualitatively different than prior simulations and that have excellent agreement with experimental results. Our approach predicts a much higher barrier to full desolvation of the material, suggesting that materials that appear to be aggregated in fact still retain monolayers of solvent between adjacent layers of 2D materials. This work provides much needed understanding on the interactions between the solvent and 2D material that can guide future experimental work.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft)
Macroscopic fluctuation theory of stochastic systems undergoing monitoring
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
João Costa, Pedro Ribeiro, Andrea De Luca
We develop a macroscopic fluctuation theory for diffusive classical lattice gases subject to continuous coarse-grained monitoring. Treating measurements in the typical-outcome (quenched) regime, we show that observation adds a quadratic confining term to the MFT action that pins the density to its hydrodynamic profile. We derive sufficient conditions under which, in the presence of monitoring, the current large-deviation function remains convex, the additivity principle holds, and dynamical phase transitions are excluded. For particle-hole-symmetric one-dimensional models we find that monitoring suppresses dynamical phase transitions and can change their order from second to first, as we demonstrate in the Katz–Lebowitz–Spohn model. In the strong-measurement limit, we find that the current distribution becomes Gaussian and determine the scaling of its cumulants: they follow simple power laws when the mobility remains nonzero throughout the system, but exhibit anomalous logarithmic scaling when the mobility vanishes at the boundaries.
Statistical Mechanics (cond-mat.stat-mech)
Flexoelectricity and Flexomagnetism
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Alexander Edström, Massimiliano Stengel
Strain gradients, unlike homogeneous strain, are odd under space inversion and unlock couplings that are strictly forbidden in the parent crystal. At the nanoscale, and in curved low-dimensional systems in particular, such gradients are readily attainable and often unavoidable, so that curvature acts as a symmetry-breaking field written into the lattice itself. This chapter reviews the resulting couplings to electric polarization and magnetism. After establishing the geometric relation between strain gradients and curvature, we review flexoelectricity as the better-established reference case: the bulk, surface and dynamic contributions that complicate its definition, its microscopic mechanisms, its manifestation in two-dimensional materials, and the first-principles methodology now available for its calculation. Using the magnetoelectric effect as a conceptual bridge, we then develop flexomagnetism in a broad sense, covering any coupling phenomena between magnetism and strain gradients, and specifically discuss the linear magnetization response to curvature and curvature-induced Dzyaloshinskii-Moriya interactions, beyond the established curvilinear treatment. Finally, we briefly describe some additional effects fitting under this broad umbrella of flexomagnetism, including nonlinear ones, inhomogeneous magnetoelectric and Rashba-type phenomena, and connections to altermagnetism.
Materials Science (cond-mat.mtrl-sci)
34 pages, 3 figures. Chapter to appear in The Effects of Curvature in Condensed Matter Physics, eds. P. Gentile, D. Makarov, C. Ortix (Springer, Springer Tracts in Modern Physics)
Phases of a rotating Bose-Einstein condensate trapped in a hard-wall potential
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-14 20:00 EDT
Hélène Perrin, G. M. Kavoulakis
We investigate the rotational properties of a zero-temperature Bose-Einstein condensed gas, which is confined in a hard-wall potential. For weak interactions the gas carries its angular momentum via vortices of multiple quantization. As the coupling increases and for sufficiently slow rotational frequencies of the trap, the multiply-quantized vortex states become unstable against a mixed state. For stronger couplings, as the angular frequency of the trap increases, there is a transition from a vortex lattice, to a vortex lattice with a hole at the trap center, and finally to a giant vortex. For weak effective attractive interactions we still have vortices of multiple quantization. These states become unstable towards states which break the axial symmetry of the problem and resemble center-of-mass excitation, as the coupling becomes more negative. Finally, for even more attractive forces, the system becomes unstable against collapse.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
10 pages, 10 figures
Imaging Gate-Tunable Single-Layer Molecular Kagome Lattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Ziyi Wang, Rafal Zuzak, Weichen Tang, Haowen Pang, Yutang Qiao, Dhanvanth Balakrishnan, Yuqiao Yan, Aining Hu, Andrew Sun, Takashi Taniguchi, Kenji Watanabe, Feng Wang, Steven G. Louie, Michael F. Crommie
Kagome lattices provide a simple geometry for engineering electronic states that exhibit novel quantum behavior. In conventional kagome materials, however, the relevant states are often embedded in chemically complex three-dimensional crystals and are difficult to isolate or tune. Molecule-based kagome networks offer structural precision and tunability, but have largely been confined to metallic substrates incompatible with 2D devices. Here we report growth of single-layer Ni$ _3$ (HITP)$ _2$ metal-organic frameworks (MOFs) on van der Waals substrates including graphene-based field-effect devices using metal-salt molecular beam epitaxy. Low-temperature scanning tunneling spectroscopy resolves kagome-derived flat-band and van Hove singularity-based spectral features consistent with first-principles calculations. Gating hybrid 2D MOF devices allows us to energetically shift kagome spectral features, thus establishing electrostatic control of chemically programmable 2D kagome electronic lattices.
Materials Science (cond-mat.mtrl-sci)
15 pages, 5 figures
A Transferable Machine-Learned Potential Enabling Large-Scale Copper-Carbon Simulations from Equilibrium to Extreme Conditions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Feiyu Zhou, Wei Qiu, Yan Chen, Jiahui Liu, Yilun Liu, Shengying Yue, Penghua Ying
Cu-C materials and interfaces are central to diamond thermal management, metallization, graphene growth and carbon-coating technologies, but atomistic simulations across these applications require a potential that describes metallic Cu, diverse carbon bonding, heterogeneous Cu-C interactions and close atomic encounters. Here we develop NEP-CuC, a transferable neuroevolution potential trained on a dataset of 2,727 uniformly relabelled configurations selected from a heterogeneous Cu-C candidate pool. Disagreement within an ensemble of five independently trained models provides an internal indicator of model sensitivity. A Ziegler-Biersack-Littmark (ZBL) correction describes short-range nuclear repulsion, while a runtime D3(BJ) correction supplements dispersion-sensitive calculations. Tests on source-derived held-out and independent external datasets, together with structural, elastic, defect, interfacial, vibrational and finite-temperature transport benchmarks, establish broad but property-dependent physical fidelity across elemental Cu, diverse carbon environments and heterogeneous Cu-C configurations. Large-scale simulations of amorphous-carbon formation and orientation-dependent shock compression of Cu further test transferability under strongly non-equilibrium conditions. For Cu/diamond interfaces, the same potential describes deposition, annealing and tensile response: preparation history leaves persistent differences in interphase structure, while the mean peak nominal tensile stress at 500 K decreases from $ 12.35\pm0.71$ to $ 6.65\pm0.98$ GPa as the incident Cu energy during the initial deposition stage increases from 1 to 50 eV. NEP-CuC provides an atomistic framework for linking processing, interfacial structure and physical response across Cu-C systems, with direct relevance to Cu/diamond thermal-management interfaces, diamond metallization and non-equilibrium Cu-C processing.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
19 pages, 10 figures
Direct growth of crystalline spinel GaON films: A wide-bandgap mixed-anion semiconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Baikui Li, Zecheng Yang, Wenhao Yin, Zijing Wu, Haitao Zhao, Yunwei Sheng, Honglei Wu, Jiannong Wang
Mixed-anion semiconductors offer opportunities for bandgap engineering beyond conventional multication alloys, but competing phases and disorder complicate their synthesis and the identification of their electronic properties. Gallium oxynitride (GaON) could connect the technologically important GaN and Ga2O3 systems, yet establishing a clear relation between its crystal structure, composition and bandgap remains challenging. Here we report the direct growth of crystalline spinel gamma-GaON films by nitrogen-plasma-assisted pulsed-laser deposition. Varying the nitrogen and oxygen supply yields monoclinic beta-Ga2O3, predominantly disordered films and crystalline spinel GaON. Complementary diffraction, atomic-resolution microscopy and elemental analysis establish the spinel structure and nitrogen incorporation. Temperature-dependent photocurrent spectroscopy reveals a clear redshift of the crystalline gamma-GaON response, supporting assignment of a band-edge transition near 4.3 eV at room temperature. These results open opportunities to investigate mixed-anion wide-bandgap semiconductor physics and develop heterostructures.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
13 pages, 4 figures
Time-Resolved Phonon Dispersions of Thermally Excited Graphite at the Nanoscale
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Mairi McCauley, Christoph T. Koch, Benedikt Haas (Department of Physics and Center for the Science of Materials Berlin, Humboldt-Universität zu Berlin, Berlin, Germany)
Lattice vibrations govern the propagation of heat in materials, and investigating their dynamics through time-resolved phonon dispersion measurements would provide insight into these excitations and their interactions. However, time-resolved measurements that directly resolve the phonon dispersion at the nanoscale have not been previously demonstrated. Momentum-resolved vibrational electron energy loss spectroscopy (EELS) provides access to phonon energies and momenta with nanoscale spatial resolution. Here, we combine momentum-resolved vibrational EELS with pulsed laser heating and synchronised gated electron detection to observe the phonon dispersion of graphite during controlled heating and cooling on the microsecond timescale. Recording both the gain and loss spectra at defined times relative to laser excitation, we determine the temperature at each time delay and follow changes to the phonon branches as a function of temperature. The momentum-resolved spectra reveal a decrease in energy of the optical phonon branch with increasing temperature accompanied by an increase in peak width. These changes are consistent with temperature-dependent phonon renormalisation and scattering associated with anharmonic interactions. The approach is compatible with detector gating on timescales down to 50 ns, providing a route towards extending these measurements to faster dynamics. This work demonstrates time-resolved phonon dispersion spectroscopy using vibrational EELS and provides a route towards probing temperature-dependent phonon dynamics at the nanoscale with simultaneous energy and momentum resolution.
Materials Science (cond-mat.mtrl-sci)
Exact Microscopic One-Body Reduction in the Symmetric Exclusion Process
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Olivier Bénichou, Aurélien Grabsch
The symmetric exclusion process (SEP) is a paradigmatic model of interacting particle transport. Its current–density correlations are governed by an infinite many-body hierarchy of equations. Only recently, this hierarchy was found to collapse at large scales onto a single closed equation. Is this remarkable simplification created by coarse graining, or does it reflect a deeper property already present in the microscopic dynamics? Here we show that the second scenario is realized. At arbitrary time on the lattice, the entire hierarchy collapses onto a single linear equation which is exactly equivalent to a persistence problem for a single auxiliary random walker. Thus an interacting many-body problem reduces exactly to a genuine one-body problem before any scaling limit is taken. This reduction determines the complete finite-time correlation profile, including during nonequilibrium relaxation. More broadly, the microscopic operator uncovered here opens a route to more general correlation functions in the SEP, and may point to a general organizing principle for nonequilibrium interacting particle systems.
Statistical Mechanics (cond-mat.stat-mech)
5 pages + 3 pages of appendices
Plasmon modes in triple-point semimetal, its quadratic cousin, and Hopf semimetal
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
We study collective charge excitations in pseudospin-1 triple-point semimetals within the random-phase approximation, considering both the linearised model with a flat-band and its quadratic-corrected counterpart. We analyse their density response, Drude weights, screening, plasmon dispersion and damping, particle-hole continua, and Friedel oscillations from the long-wavelength to the arbitrary-momentum regime. The quadratic correction renders the flat-band dispersive and endows it with a Fermi surface, thereby affecting the overall response. Comparisons with Weyl and Hopf semimetals reveal how bandstructure and quantum geometry jointly govern collective charge dynamics. While the Drude weights are determined by the Fermi surface and band-velocities, interband screening, plasmon dispersion, and Friedel oscillations reflect the quantum geometry of the eigenstates.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
continuation of plasmon studies in semimetals
Momentum conservation for ab initio calculations with pseudopotentials via a phase space electronic structure formulation
New Submission | Other Condensed Matter (cond-mat.other) | 2026-10-14 20:00 EDT
Guy Ohad, Nadine C. Bradbury, Joseph E. Subotnik
We demonstrate how to build a robust phase space electronic Hamiltonian $ \hat{H}_\text{PS}(\boldsymbol{R},\boldsymbol{P})$ that depends on nuclear position $ \boldsymbol{R}$ and nuclear momentum $ \boldsymbol{P}$ in the presence of ionic pseudopotentials. In particular, we show that in order to account for the non-local component of a pseudopotential while also conserving linear and angular momentum, one is forced to introduce a non-local one-electron operator $ \hat{\boldsymbol{\Gamma}}^\text{nl}$ that couples electronic and nuclear momenta together. To test the validity of our ansatz, we derive a generalized form of Nafie’s exact equality (which relates electronic momentum and electronic position) so as to include the presence of pseudopotentials. We then benchmark our proposed phase space electronic structure theory against this generalized Nafie-like result for a diverse set of diatomic molecules spanning a wide range of elements. We find excellent agreement across this ab initio test set, highlighting the strength of our method in capturing meaningful electronic momentum beyond the Born-Oppenheimer framework.
Other Condensed Matter (cond-mat.other)
Extending the mean first-passage-time formalism to the reconstruction of high free-energy barriers: A top-start approach
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Rare events, such as crystal nucleation in mildly supercooled liquids, are characterized by waiting times that can be much longer than the timescale of the underlying microscopic dynamics. The mean first-passage time (MFPT) formalism [J. Wedekind and D. Reguera, J. Phys. Chem. B 112, 11060 (2008)] provides a route to reconstruct one-dimensional free-energy profiles from the MFPT and steady-state distribution measured along a reaction coordinate, but conventional implementations become inefficient for sufficiently high barriers because spontaneous crossings are rarely observed. We introduce a “top-start” extension that initiates trajectories near the barrier top and reconstructs the free-energy profile from their subsequent evolution away from the barrier toward lower-free-energy regions. We establish the equivalence between the top-start and two-region constructions using a Markov-chain transition-matrix formulation. We validate the method using one-dimensional random-walk simulations across low, medium, and high free-energy barriers, with transition-matrix calculations providing an exact benchmark for the corresponding discretized models. The top-start reconstruction remains accurate in the high-barrier regime where conventional MFPT sampling becomes prohibitively inefficient.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
19 pages, 6 figures
Dark state preparation in a zero-field-split molecular triplet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Maria Pfahler, Andrea Donarini
We propose a protocol to prepare and probe dark states in a single-molecule electron spin resonance based on atomic force microscopy (ESR-AFM), thus extending existing techniques developed to address Rabi oscillations. To this end, we simulate in analogy to atomic physics the coherent manipulation of a three-level system in the V-configuration using a multifrequency magnetic field. More specifically, we consider a neutral molecule with a zero-field-split (ZFS) first excited triplet and analyze within a pump-probe scheme the dynamics of the total triplet population. In the triplet subspace, the dark state is a coherent superposition formed by two ZFS states which does not evolve in time despite a continuous resonant driving towards the third one. We characterize the properties of this state comparing it to its fully incoherent counterpart. Within a density-matrix formalism for open systems, we then compute the expected dark state signatures both for ideal scenarios and for the realistic parameterization of ESR-AFM on pentacene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
17 pages, 11 figures
Composition-controlled optical fingerprints and anisotropy of self-trapped excitons in double perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2026-10-14 20:00 EDT
Simone Grillo, Offir Zachs Maishlos, Liya Koren, Rotem Strassberg, Rachel Lifer, Edi Maizenberg, Umberto De Giovannini, Angel Rubio, Yehonadav Bekenstein, Ofer Neufeld
Double perovskites (DPs) offer a compositionally versatile platform for photocatalysis and optoelectronics, but their soft lattices favor strong exciton-phonon coupling and self-trapped excitons (STEs), which produce broad, red-shifted photoluminescence (PL). Here, we combine optical spectroscopy and ab initio calculations to study lead-free, Sb-doped Cs2BInCl6 nanocrystals with B-site alloying from Na to K. Alloying tunes the PL energy from about 2.48 to 2.70 eV, while absorption features near 3.8 eV remain nearly unchanged. Calculations reveal that Sb doping enables bright radiative recombination channels and delocalizes the excitonic wavefunction. We identify STEs responsible for the large PL red shift, associated with an upward shift of dopant-hybridized in-gap states. Na-to-K substitution selectively changes the STE lattice distortion, explaining why PL varies strongly with composition while absorption does not. Theory further predicts pronounced PL polarization anisotropy that reflects the STE wavefunction’s spatial structure and depends on B-site composition. Time-resolved anisotropy measurements closely agree with these predictions, providing experimental fingerprints of the excitonic wavefunction and its evolution with alloying. Together, these results disentangle the roles of doping and alloying in lead-free DPs and establish polarization-resolved spectroscopy as a probe of STE wavefunctions.
Materials Science (cond-mat.mtrl-sci)
23 pages, 5 figures
Superexchange coupling between a dilute Gd3+ probe and orphan spins in a valence-bond glass
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Patrick Colgan, Artur Solodovnyk, Jeremy P. Carlo, Scott Dietrich
The valence-bond-glass state of the 4d^1 double perovskite Ba2YMoO6 combines Mo^5+ singlets with residual paramagnetic “orphan” spins whose coupling is hard to reach with bulk probes. We probe them by electron paramagnetic resonance of a dilute Gd^3+ ion on the Y^3+ site via broadband coplanar-waveguide transmission at 5 K. The isostructural nonmagnetic niobate Ba2YNbO6, doped with the same Gd^3+ probe, is a fixed-lattice control. The Gd^3+ linewidth nearly doubles in the magnetic host. Dipolar coupling to the sparse orphans is nearly an order of magnitude too weak; the excess is instead reproduced by a transferred f-d superexchange of J ~ 0.2 K, so the width is a static measure of orphan-spin coupling. The half-field (Delta m_S = +/-2) satellite collapses in the magnetic host, a dynamical dephasing channel, while the unchanged g-factor marks a zero-mean random internal field. Together the two channels probe the coupling and dynamics of valence-bond-glass orphan spins.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
Emergent Loop Geometry in Gauge-Equivariant Graph Neural Networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Gauge-equivariant graph neural networks generate ordered products of gauge links through local message passing, but the geometry of these internal structures is not captured by the receptive field alone. We investigate the statistical ensemble of closed lattice walks generated by recursive node- and edge-feature operations, independently of network training. Analytical and numerical results reveal a separation between rapid growth of contour length and much slower spatial expansion: deeper compositions generate increasingly long paths through repeated traversal of relatively compact regions. Loop expansions of fermionic observables provide a physical interpretation of this hierarchy, showing how spatial locality remains compatible with high-order dependence on nearby gauge fields. These findings identify complementary roles of network depth in extending spatial reach and enriching the representations constructed within that reach, providing a geometrical perspective on learning lattice gauge observables.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Machine Learning (cs.LG), High Energy Physics - Lattice (hep-lat)
16 pages, 8 figures
Competing delocalisation and localisation induced by the dipolar tail in fragmented lattice gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2026-10-14 20:00 EDT
Sabhyata Gupta, Adith Sai Aramthottil, Luis Santos
We investigate how the long-range tail of dipole-dipole interactions modifies the dynamics of strongly interacting hard-core bosons in a one-dimensional lattice. In the nearest-neighbour model, large interactions generate an emergent Hilbert-space fragmentation into manifolds labelled by the number of nearest-neighbour bonds (N_{\mathrm{NN}}). The dipolar tail has a non-monotonic effect on this fragmented dynamics as the interaction-to-tunnelling ratio (V/t) is increased. At intermediate (V/t), it enhances delocalisation relative to the nearest-neighbour model by reducing the energetic detuning between neighbouring (N_{\mathrm{NN}}) manifolds and sustaining their hybridisation by hopping. At larger (V/t), the same tail lifts degeneracies within each manifold, beginning with the splitting associated with the next-nearest-neighbour bond number (N_{\mathrm{NNN}}), and promotes intra-manifold localisation and Hilbert-space shattering. The competition between these two effects produces a crossover from a delocalising to a localising role of the dipolar tail, visible in the late-time spatial inhomogeneity. This crossover occurs for nearly all initial states considered and persists at different fillings. Transverse confinement strengthens the short-range part of the dipolar tail and shifts the crossover to lower (V/t), bringing it into the regime relevant to current experiments with magnetic atoms and polar molecules.
Quantum Gases (cond-mat.quant-gas)
comments welcome!
Spin textures at the Fermi surface of ferromagnets and associated torque
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
T. Valet, J. Li, H. Jaffrès, V. Cros, M. Chshiev, R. Raimondi
We establish theoretically that transverse spin textures are generically induced by the spin-orbit interaction at the Fermi surface of centrosymmetric ferromagnetic metals. We confirm this prediction with {\em ab initio} computations for Fe, Co and Ni. By symmetry, this cannot be associated with spin-orbit torques under a uniform current. However, a new {\em current-gradient-induced} torque emerges in nanoscale geometries. For a series of Ni-based bilayers, the computed Ni thickness dependence of the current-gradient-induced torque is in quantitative agreement with measurements previously attributed to orbital torques. We discuss how this opens a new avenue for the electrical control of magnetic orders, possibly also including the Néel vector of metallic altermagnets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Towards synergy between theory and experiments: First-passage processes under resetting with stochastic return protocols
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2026-10-14 20:00 EDT
Stochastic resetting with stochastic return (SR) has recently emerged as an effective and practically relevant strategy for controlling first-passage phenomena and optimizing search processes by significantly reducing completion times in a wide class of stochastic systems. While most theoretical studies assume instantaneous return (IR), in realistic systems the return to the resetting position typically occurs over a finite time. We consider a 1-d diffusing particle in a harmonic trap with stiffnesses $ k_1$ and $ k_2$ during search and return, respectively. The particle searches for the target and, upon resetting at rate $ r$ , enters the return phase, continuing until it reaches either the origin or the absorbing target at $ L>0$ . Notably, the model permits target detection throughout the return phase, distinguishing it from IR scenarios. We analytically derive the MFPT for our model and determine parameter regions where SR enhances or suppresses search efficiency over the underlying dynamics, constructing the corresponding phase diagram using the coefficient of variation criterion. We further identify regimes in which SR is more efficient than IR using the SR criterion. This behavior is tested across different parameter sets taken from experimental studies by Goerlich et al., Biroli et al., and Besga et al. We map the parameter values reported in existing experimental studies onto our theoretical phase diagram, thereby identifying the regimes in which SR outperforms IR. In particular, we find that the most relevant region of the phase space, where SR is most beneficial corresponds to larger values of the potential strength in the search phase and lower values of potential in the return phase. Our results provide experimentally testable predictions and bridge the gap between theoretical resetting models and optical trap mediated finite-time return dynamics.
Statistical Mechanics (cond-mat.stat-mech)
Single anyons and anyon binding in a quantum Hall dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2026-10-14 20:00 EDT
Marco Valentini, Will Wang, Amir Shapour Mohammadi, Noah Samuelson, Chengxuan Li, Liam Cohen, Mark Zakharyan, Jiechao Feng, Taige Wang, Takashi Taniguchi, Kenji Watanabe, Michael P. Zaletel, Andrea F. Young
Anyons are particles with quantized fractional statistics. In theory, a single anyon can be stabilized as a localized fractional charge within the bulk of a topologically ordered two-dimensional insulator. However, experiments to date have focused on probing anyons in structures in which many anyonic excitations coexist and interact. Here, we demonstrate the trapping of a single anyon in a device consisting of a graphene-based quantum point contact with an embedded tunable quantum Hall dot. Benchmarking our device at v = 1, we demonstrate backscattering between Fermi liquid edge states mediated by the whole-electron Coulomb blockade of the dot. The cleanliness and control available in our device allow depletion of the dot to the last quasihole, and we observe spin blockade for transitions to the opposite-spin Landau level. At v = 1/3 and 2/3, we observe backscattering resonances with three times the frequency, consistent with resonant transmission of e/3 charges via a single anyon transistor. We demonstrate controlled depletion to the last quasiparticle to form a single anyon quantum dot. Tracing the charge addition spectrum for quasiparticle number Nqp = 1-5, we observe highly irregular addition energies, consistent with DMRG modeling showing a complex orbital shell-filling behavior. At higher Nqp = 10-20, the addition energies show a striking pattern: quasiholes at 1/3 (and quasiparticles at 2/3) show a regular addition spectrum while quasiparticles at 1/3 (and quasiholes at 2/3) do not. We trace the origin of this irregularity to an attractive component of the inter-anyon interaction: by experimentally tuning the confining energy, we observe complete suppression of alternating charge sectors, after which the dot charges in increments of twice the fundamental charge. This observation indicates the emergence of an anyon binding energy as large as the charging energy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
A hierarchy of exact lower bounds on the Laughlin spectral gap
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2026-10-14 20:00 EDT
Michael G. Scheer, Eslam Khalaf
We develop a bootstrap approach to deriving lower bounds on the spectral gap of the first Haldane pseudopotential Hamiltonian on the sphere with $ N_\Phi$ flux quanta for arbitrary $ N_\Phi$ , including in the thermodynamic limit $ N_\Phi \to \infty$ . Our approach can in principle be generalized to pseudopotentials describing other model wavefunctions such as the Moore-Read state or Read-Rezayi sequence. Our approach is based on Knabe’s observation that if $ H$ is a Hamiltonian with ground state energy $ 0$ then the spectral gap is at least $ \epsilon > 0$ if and only if $ H^2 \succeq \epsilon H$ . To show this inequality, we split $ H^2$ into two parts, one that can be analytically bounded and another that can be bounded using a finite semidefinite program (SDP). Crucially, the size of this program is determined only by cutoff parameters, and the program depends on $ N_\Phi$ only parametrically, allowing us to obtain numerically exact (up to solver precision) lower bounds on the gap. In order to turn these numerical bounds into mathematically rigorous bounds, we introduce an algorithm that can produce nearly-optimal exact feasible points for large rational SDPs. We additionally provide an algorithm that establishes the rank stability of the semidefinite program in the limit $ N_\Phi \to \infty$ which is needed to certify the bound in the thermodynamic limit. Beyond establishing the Laughlin gap and revealing a potential method for deriving spectral gap lower bounds for other pseudopotentials, our work provides a general method for turning numerical semidefinite programming bounds into rigorous mathematical proofs, which may have wide applicability.
Strongly Correlated Electrons (cond-mat.str-el)
Research Square
Frequency-agile integrated mid-infrared electro-optic comb
Article | Nonlinear optics | 2026-10-13 20:00 EDT
Pierre Didier, Prakhar Jain, Tristan Kuttner, Oliver Pitz, Rachel Grange
Mid-infrared frequency combs provide highly sensitive and selective access to molecular vibrational transitions, making them attractive for integrated spectroscopic sensing. However, compact sources offering broad wavelength coverage together with independent electronic control of comb parameters remain challenging to realize. Here, we demonstrate mid-infrared electro-optic frequency-comb generation through difference-frequency generation in periodically poled thin-film lithium niobate waveguides implemented on two substrates, namely silicon dioxide and sapphire. Our architecture combines a continuous-wave near-infrared pump with a telecom-band electro-optic comb operated in either single- or dual-comb configurations, generated on-chip. Difference-frequency generation allows downconversion of the telecom comb to the mid-infrared. The comb spacing is defined by the drive radio frequency, while the comb center frequency is independently controlled by the telecom seed wavelength. The quasi-phase-matching condition can be further tuned through temperature control. We generate mid-infrared combs with an instantaneous bandwidth of approximately 6 nm and a center-wavelength tuning range exceeding 200 nm on a single device. A direct comparison of the device on two substrates reveals the advantage of lithium niobate on sapphire for operation beyond 3.5 µm, providing higher output power, improved conversion efficiency, and extended spectral coverage up to 4.5 µm. Finally, we demonstrate on-chip dual-comb generation in the mid-infrared with a tunable relative frequency offset between the two combs. Low-frequency beat notes between corresponding comb lines are detected over a 140 nm MIR wavelength range. This unique integrated mid-infrared electro-optic comb platform combines independent electronic control of the comb center frequency, line spacing, and frequency offset with on-chip dual-comb generation.
Research Square:rs-10729821 (2026)
Posted on Research Square and Under Review at Nature Portfolio
Physical sciences/Optics and photonics/Optical physics/Nonlinear optics, Physical sciences/Optics and photonics/Applied optics/Mid-infrared photonics, Physical sciences/Optics and photonics/Applied optics/Integrated optics
Vapor-liquid-solid epitaxy of wafer-scale perovskite single crystals
Article | Surfaces, interfaces and thin films | 2026-10-13 20:00 EDT
Guifu Zou, Yuan Chen, Guijia Hu, Jianmei Chen, Wei Zhang, Yongshu Wang, Hongcao Shi, Jinchuan Cao, Guoxiang Zhao, Chen Wang, Peipei Ma, Hao Wang, Shan Cong
Wafer-scale halide perovskite single-crystal films are highly sought after for integrated optoelectronic applications. However, conventional vapor-phase growth suffers from poor substrate wettability and restricted precursor diffusion, consequences of the high interfacial energies inherent to vapor-solid interfaces at both the vapor-substrate and vapor-film boundaries. Here, we report catalyst-free vapor-liquid-solid (VLS) growth of 2-inch perovskite single-crystal wafers. This process is mediated by a condensed halide-rich liquid intermediate that establishes complete surface wetting and replaces high-energy vapor-solid interfaces with low-energy liquid-solid interfaces, thereby substantially reducing the nucleation energy barrier and nucleation density. The liquid-phase medium also dramatically extends metal halide solute migration distances, enabling edge-dominated layer growth and seamless coalescence of oriented nuclei. We demonstrate the generality of this approach by fabricating wafer-scale films of CsPbBr₃, CsPbCl₃, and their alloys. Atomic-scale microscopy and wafer-scale spectroscopy confirm exceptional crystalline uniformity, ultralow trap-state density, and superior electronic and optoelectronic quality.
Research Square:rs-11177182 (2026)
Posted on Research Square and Under Review at Nature Portfolio
Physical sciences/Physics/Condensed-matter physics/Surfaces, interfaces and thin films, Physical sciences/Materials science/Techniques and instrumentation/Design, synthesis and processing