CMP Journal 2025-04-11
Statistics
Nature Nanotechnology: 2
Nature Physics: 1
Science: 6
Physical Review Letters: 2
Physical Review X: 1
arXiv: 58
Nature Nanotechnology
Inversion of supramolecular chirality by photo-enhanced secondary nucleation
Original Paper | Molecular self-assembly | 2025-04-10 20:00 EDT
Takuho Saito, Daisuke Inoue, Yuichi Kitamoto, Hiroki Hanayama, Takatoshi Fujita, Yuki Watanabe, Masayuki Suda, Takashi Hirose, Takashi Kajitani, Shiki Yagai
Understanding how molecules in solution begin to nucleate and grow into defined aggregates remains an outstanding mechanistic challenge. This is because the nucleation process is affected by a number of physicochemical factors that act simultaneously and whose individual contributions are hard to disentangle. Here, we demonstrate how residual aggregates in a molecular dispersion state affect the nucleation kinetics and the resulting self-assembly pathway. Using the photoisomerization of a chiral azobenzene molecule, the amounts of residual aggregates can be controlled in the pre-assembly supersaturated solution. The residual aggregates induce surface-catalysed secondary nucleation of monomers, affecting the chiral intermolecular configuration during self-assembly to afford metastable right-handed P-aggregates as opposed to thermodynamically stable left-handed M-aggregates. By exploiting the photoisomerization process, we establish high-fidelity control over the nucleation processes and demonstrate reversible M ⇄ off ⇄ P tristate switching of supramolecular chirality. Finally, we show that chiral aggregates exhibit opposite chirality-induced spin selectivities with high spin-polarization rates.
Molecular self-assembly, Supramolecular chemistry
From small batteries to big claims
Original Paper | Batteries | 2025-04-10 20:00 EDT
Rares-George Scurtu, Alessandro Innocenti, Vanessa Scheck, Mario Maunz, Thomas Waldmann, Markus Hölzle, Alice Hoffmann, Peter Axmann, Margret Wohlfahrt-Mehrens
A frequently undervalued aspect of lithium-ion battery performance reporting is the specification of the format and area of the tested cells. However, these parameters provide crucial insights into the quality of the electrodes used for cell assembly and the reliability of the data obtained from the investigated systems. Here we focus on the aspects of process standardization and industry collaboration necessary for translating nanoscale electrochemical processes to Ah-scale cells. We examine the role of cell area and format in promoting comparability and standardization in battery research studies with technology readiness levels of 4 or higher. In addition, we discuss the limitations, challenges and expectations associated with measuring and evaluating battery performance exclusively in small cell formats.
Batteries, Electrochemistry, Energy science and technology, Energy storage, Engineering
Nature Physics
Continuous recoil-driven lasing and cavity frequency pinning with laser-cooled atoms
Original Paper | Atomic and molecular interactions with photons | 2025-04-10 20:00 EDT
Vera M. Schäfer, Zhijing Niu, Julia R. K. Cline, Dylan J. Young, Eric Yilun Song, Helmut Ritsch, James K. Thompson
Laser-cooled gases of atoms interacting with the field of an optical cavity are a versatile tool for quantum sensing and the simulation of quantum systems. These systems can exhibit phenomena such as self-organization phase transitions, lasing mechanisms, squeezed states and protection of quantum coherence. However, investigations of these phenomena typically occur in a discontinuous manner due to the need to reload atomic ensembles. Here we demonstrate hours-long continuous lasing from laser-cooled 88Sr atoms loaded into a ring cavity. The required inversion to produce lasing arises from inversion in the atomic-momentum degrees of freedom, which is linked to the self-organization phase transitions and collective atomic recoil lasing observed previously only in a cyclic fashion. We find that over a broad parameter range, the sensitivity of the lasing frequency to changes in cavity frequency is significantly reduced due to an atomic loss mechanism, suggesting a potential approach for mitigating low-frequency cavity noise. Our findings open opportunities for continuous cavity quantum electrodynamics experiments and robust and continuous super-radiant lasers.
Atomic and molecular interactions with photons, Quantum metrology
Science
Retrograde mitochondrial signaling governs the identity and maturity of metabolic tissues
Research Article | Metabolism | 2025-04-11 03:00 EDT
Emily M. Walker, Gemma L. Pearson, Nathan Lawlor, Ava M. Stendahl, Anne Lietzke, Vaibhav Sidarala, Jie Zhu, Tracy Stromer, Emma C. Reck, Jin Li, Elena Levi-D’Ancona, Mabelle B. Pasmooij, Dre L. Hubers, Aaron Renberg, Kawthar Mohamed, Vishal S. Parekh, Irina X. Zhang, Benjamin Thompson, Deqiang Zhang, Sarah A. Ware, Leena Haataja, Nathan Qi, Stephen C. J. Parker, Peter Arvan, Lei Yin, Brett A. Kaufman, Leslie S. Satin, Lori Sussel, Michael L. Stitzel, Scott A. Soleimanpour
Mitochondrial damage is a hallmark of metabolic diseases, including diabetes, yet the consequences of compromised mitochondria in metabolic tissues are often unclear. In this work, we report that dysfunctional mitochondrial quality control engages a retrograde (mitonuclear) signaling program that impairs cellular identity and maturity in β cells, hepatocytes, and brown adipocytes. Targeted deficiency throughout the mitochondrial quality control pathway, including genome integrity, dynamics, or turnover, impaired the oxidative phosphorylation machinery, activating the mitochondrial integrated stress response, eliciting chromatin remodeling, and promoting cellular immaturity rather than apoptosis to yield metabolic dysfunction. Pharmacologic blockade of the integrated stress response in vivo restored β cell identity after the loss of mitochondrial quality control. Targeting mitochondrial retrograde signaling may therefore be promising in the treatment or prevention of metabolic disorders.
A distinct priming phase regulates CD8 T cell immunity by orchestrating paracrine IL-2 signals
Research Article | Immunology | 2025-04-11 03:00 EDT
Katarzyna Jobin, Deeksha Seetharama, Lennart Rüttger, Chloe Fenton, Ekaterina Kharybina, Annerose Wirsching, Anfei Huang, Konrad Knöpper, Tsuneyasu Kaisho, Dirk H. Busch, Martin Vaeth, Antoine-Emmanuel Saliba, Frederik Graw, Alain Pulfer, Santiago F. González, Dietmar Zehn, Yinming Liang, Milas Ugur, Georg Gasteiger, Wolfgang Kastenmüller
T cell priming is characterized by an initial activation phase that involves stable interactions with dendritic cells (DCs). How activated T cells receive the paracrine signals required for their differentiation once they have disengaged from DCs and resumed their migration has been unclear. We identified a distinct priming phase that favors CD8 T cells expressing receptors with high affinity for antigen. CXCR3 expression by CD8 T cells was required for their hours-long reengagement with DCs in specific subfollicular niches in lymph nodes. CD4 T cells paused briefly at the sites of CD8 T cell and DC interactions and provided Interleukin-2 (IL-2) before moving to another DC. Our results highlight a previously unappreciated phase of cell-cell interactions during T cell priming and have direct implications for vaccinations and cellular immunotherapies.
The genetic architecture of and evolutionary constraints on the human pelvic form
Research Article | Evolution | 2025-04-11 03:00 EDT
Liaoyi Xu, Eucharist Kun, Devansh Pandey, Joyce Y. Wang, Marianne F. Brasil, Tarjinder Singh, Vagheesh M. Narasimhan
Human pelvic evolution following the human-chimpanzee divergence is thought to result in an obstetrical dilemma, a mismatch between large infant brains and narrowed female birth canals, but empirical evidence has been equivocal. By using deep learning on 31,115 dual-energy x-ray absorptiometry scans from UK Biobank, we identified 180 loci associated with seven highly heritable pelvic phenotypes. Birth canal phenotypes showed sex-specific genetic architecture, aligning with reproductive function. Larger birth canals were linked to slower walking pace and reduced back pain but increased hip osteoarthritis risk, whereas narrower birth canals were associated with reduced pelvic floor disorder risk but increased obstructed labor risk. Lastly, genetic correlation between birth canal and head widths provides evidence of coevolution between the human pelvis and brain, partially mitigating the dilemma.
Rules of engagement for condensins and cohesins guide mitotic chromosome formation
Research Article | Molecular biology | 2025-04-11 03:00 EDT
Kumiko Samejima, Johan H. Gibcus, Sameer Abraham, Fernanda Cisneros-Soberanis, Itaru Samejima, Alison J. Beckett, Nina Puǎčeková, Maria Alba Abad, Christos Spanos, Bethan Medina-Pritchard, James R. Paulson, Linfeng Xie, A. Arockia Jeyaprakash, Ian A. Prior, Leonid A. Mirny, Job Dekker, Anton Goloborodko, William C. Earnshaw
We used Hi-C, imaging, proteomics, and polymer modeling to define rules of engagement for SMC (structural maintenance of chromosomes) complexes as cells refold interphase chromatin into rod-shaped mitotic chromosomes. First, condensin disassembles interphase chromatin loop organization by evicting or displacing extrusive cohesin. Second, condensin bypasses cohesive cohesins, thereby maintaining sister chromatid cohesion as sisters separate. Studies of mitotic chromosomes formed by cohesin, condensin II, and condensin I alone or in combination lead to refined models of mitotic chromosome conformation. In these models, loops are consecutive and not overlapping, implying that condensins stall upon encountering each other. The dynamics of Hi-C interactions and chromosome morphology reveal that during prophase, loops are extruded in vivo at ∼1 to 3 kilobases per second by condensins as they form a disordered discontinuous helical scaffold within individual chromatids.
A neuroimmune circuit mediates cancer cachexia-associated apathy
Research Article | Neuroscience | 2025-04-11 03:00 EDT
, Sarah Starosta, Miriam Ferrer, , Quentin Chevy, Federica Lucantonio, Rodrigo Muñoz-Castañeda, , , , Francesca R. Fiocchi, Mason Bergstrom, Aubrey A. Siebels, Thomas Upin, Michael Wulf, Sarah Evans, Alexxai V. Kravitz, Pavel Osten, Tobias Janowitz, Marco Pignatelli, Adam Kepecs
Cachexia, a severe wasting syndrome associated with inflammatory conditions, often leads to multiorgan failure and death. Patients with cachexia experience extreme fatigue, apathy, and clinical depression, yet the biological mechanisms underlying these behavioral symptoms and their relationship to the disease remain unclear. In a mouse cancer model, cachexia specifically induced increased effort-sensitivity, apathy-like symptoms through a cytokine-sensing brainstem-to-basal ganglia circuit. This neural circuit detects elevated interleukin-6 (IL-6) at cachexia onset and translates inflammatory signals into decreased mesolimbic dopamine, thereby increasing effort sensitivity. We alleviated these apathy-like symptoms by targeting key circuit nodes: administering an anti-IL-6 antibody treatment, ablating cytokine sensing in the brainstem, and optogenetically or pharmacologically boosting mesolimbic dopamine. Our findings uncovered a central neural circuit that senses systemic inflammation and orchestrates behavioral changes, providing mechanistic insights into the connection between chronic inflammation and depressive symptoms.
Structural pathway for PI3-kinase regulation by VPS15 in autophagy
Research Article | Signal transduction | 2025-04-11 03:00 EDT
Annan S. I. Cook, Minghao Chen, Thanh N. Nguyen, Ainara Claveras Cabezudo, Grace Khuu, Shanlin Rao, Samantha N. Garcia, Mingxuan Yang, Anthony T. Iavarone, Xuefeng Ren, Michael Lazarou, Gerhard Hummer, James H. Hurley
The class III phosphatidylinositol-3 kinase complexes I and II (PI3KC3-C1 and PI3KC3-C2) have vital roles in macroautophagy and endosomal maturation, respectively. We elucidated a structural pathway of enzyme activation through cryo-electron microscopy analysis of PI3KC3-C1. The inactive conformation of the VPS15 pseudokinase stabilizes the inactive conformation, sequestering its N-myristate in the N-lobe of the pseudokinase. Upon activation, the myristate is liberated such that the VPS34 lipid kinase catalyzes phosphatidylinositol-3 phosphate production on membranes. The VPS15 pseudokinase domain binds tightly to guanosine triphosphate and stabilizes a web of interactions to autoinhibit the cytosolic complex and promote activation upon membrane binding. These findings show in atomistic detail how the VPS34 lipid kinase is activated in the context of a complete PI3K complex.
Physical Review Letters
Two Mechanisms Limiting the Emitted Electron Current from a Cathode to an Anode
Research article | Plasma instabilities | 2025-04-10 06:00 EDT
M. D. Campanell, C. Y. Wang, and K. L. Nguyen
It is known that the current of emitted electrons flowing through a plasma can saturate upon formation of a potential well adjacent to the cathode (the ‘’space charge effect’’). Here, we demonstrate another saturation mechanism that will often set a more restrictive limit on the global current. When ‘’backflow saturation’’ occurs, the cathode sheath weakens to allow emitted electrons that already entered the plasma to backflow to the cathode. This effect could not be captured by studies modelling the cathode sheath by itself because its origin is coupled to processes in the interior plasma and anode sheath. By modeling a full plasma diode, we show that depending on conditions the global current can be limited in four ways; by backflow alone, by space charge alone, by both mechanisms in a stable cooperative form, or by both in a competing oscillatory form.
Phys. Rev. Lett. 134, 145301 (2025)
Plasma instabilities, Plasma sources, Thermionic emission, Laboratory plasma, Plasma sheaths & surfaces
Emergent Surface Multiferroicity
Research article | Ferroelectricity | 2025-04-10 06:00 EDT
Sayantika Bhowal, Andrea Urru, Sophie F. Weber, and Nicola A. Spaldin
We show that the surface of a centrosymmetric, collinear, compensated antiferromagnet, which hosts bulk ferroically ordered magnetic octupoles, exhibits a linear magnetoelectric effect, a net magnetization, and a net electric dipole moment. Thus, the surface satisfies all the conditions of a multiferroic, in striking contrast to the bulk, which is neither polar nor exhibits any net magnetization or linear magnetoelectric response. Of particular interest is the case of nonrelativistic $d$-wave spin split antiferromagnets, in which the bulk magnetic octupoles and consequently the surface multiferroicity exist even without spin-orbit interaction. We illustrate our findings using first-principles calculations, taking ${\mathrm{FeF}}_{2}$ as an example material. Our Letter underscores the bulk-boundary correspondence in these unconventional antiferromagnets.
Phys. Rev. Lett. 134, 146703 (2025)
Ferroelectricity, Magnetism, Magnetoelectric effect, Surface & interfacial phenomena, Density functional theory
Physical Review X
Spin-Stripe Order Tied to the Pseudogap Phase in ${\mathrm{La}}{1.8-x}{\mathrm{Eu}}{0.2}{\mathrm{Sr}}{x}{\mathrm{CuO}}{4}$
Research article | Charge density waves | 2025-04-10 06:00 EDT
Anne Missiaen, Hadrien Mayaffre, Steffen Krämer, Dan Zhao, Yanbing Zhou, Tao Wu, Xianhui Chen, Sunseng Pyon, Tomohiro Takayama, Hidenori Takagi, David LeBoeuf, and Marc-Henri Julien
Stripe order of spins and charges in cuprates is linked to the pseudogap, as both phenomena are confined below the same critical electronic density. This raises new questions about the strange metal phase found above this critical density.
Phys. Rev. X 15, 021010 (2025)
Charge density waves, High magnetic fields, Magnetic phase transitions, Phase diagrams, Quantum phase transitions, High-temperature superconductors, Strongly correlated systems, Nuclear magnetic resonance
arXiv
Data-Driven Approach to Hyperelastic Membranes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
We study large deformations of hyperelastic membranes using a purely two-dimensional formulation derived from basic balance principles within a modern geometric setting, ensuring a framework that is independent of an underlying three-dimensional formulation. To assess the predictive capabilities of membrane theory, we compare numerical solutions to experimental data from axisymmetric deformations of a silicone rubber film. Five hyperelastic models - Neo-Hookean, Mooney-Rivlin, Gent, Yeoh, and Ogden - are evaluated by fitting their material parameters to our experimental data using TensorFlow. Our results provide a systematic comparison of these models based on their accuracy in capturing observed deformations, establishing a framework for integrating theory, experiment, and data-driven parameter identification.
Soft Condensed Matter (cond-mat.soft)
36 pages, 15 figures, 9 tables
Bose-Einstein Condensation and the Lambda Transition for Interacting Lennard-Jones Helium-4
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-11 20:00 EDT
An introduction to Bose-Einstein condensation and the $ \lambda$ -transition is given. Results of quantum loop Monte Carlo simulations are presented for interacting Lennard-Jones helium-4. The optimum condensation fraction is found by minimizing the constrained free energy. The results show that approaching the transition the growth of pure position permutation loops and the consequent divergence of the heat capacity are enabled by the suppression of condensation and consequently of superfluidity. Condensation and superfluidity emerge at the peak of the heat capacity due to mixed position permutation chains.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
14 pages, 4 figures
From Continuous to First-Order-Like: Amorphous-to-Amorphous Transition in Phase-Change Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Tomoki Fujita, Yoshio Kono, Yuhan Chen, Jens Moesgaard, Seiya Takahashi, Arune Makareviciute, Sho Kakizawa, Davide Campi, Marco Bernasconi, Koji Ohara, Ichiro Inoue, Yujiro Hayashi, Makina Yabashi, Eiji Nishibori, Riccardo Mazzarello, Shuai Wei
Polymorphism is ubiquitous in crystalline solids. Amorphous solids, such as glassy water and silicon, may undergo amorphous-to-amorphous transitions (AATs). The nature of AATs remains ambiguous, due to diverse system-dependent behaviors and experimental challenges to characterize disordered structures. Here, we identify two ordered motifs in amorphous phase-change materials and monitor their interplay upon pressure-induced AATs. Tuning temperature, we find a crossover from continuous to first-order-like AATs. The crossover emerges at a special pressure-temperature combination, where the AAT encounters a maximum in crystallization rate. Analyzing the two ordered motifs in a two-state model, we draw a phenomenological parallel to the phase transition behavior of supercooled water near its second critical point. This analogy raises an intriguing question regarding the existence of a critical-like point within amorphous solids.
Materials Science (cond-mat.mtrl-sci)
Quantum Geometry: Revisiting electronic scales in quantum matter
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Nishchhal Verma, Philip J. W. Moll, Tobias Holder, Raquel Queiroz
Electronic properties of solids are often well understood via the low energy dispersion of Bloch bands, motivating single band approximations in many metals and semiconductors. However, a closer look reveals new length and time scales introduced by quantum dipole fluctuations due to interband mixing, which are reflected in the momentum space textures of the electronic wavefunctions. This structure is usually referred to as quantum geometry. The scales introduced by geometry not only qualitatively modify the linear and nonlinear responses of a material but can also have a vital role in determining the many-body ground state. This review explores how quantum geometry impacts properties of materials and outlines recent experimental advances that have begun to explore quantum geometric effects in various condensed matter platforms. We discuss the separation of scales that can allow us to estimate the significance of quantum geometry in various response functions.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Review article, comments welcome
Two-dimensional nonlinear optical response of a spiral magnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
We study the dynamical response function relevant for two-dimensional coherent nonlinear optical spectroscopy of the antiferromagnetic frustrated $ J_{1}$ -$ J_{3}$ Heisenberg model on the square lattice within its long-range ordered, incommensurate diagonal spiral phase. We argue that in this phase effective dipole coupling to the electric field is important, with the spin-current coupling potentially being the dominant mechanism for spin-1/2. For this setting, we use linear spin wave theory to evaluate the leading nonlinear polarization response which is of second order in the driving field. We show that the response function features a strong antidiagonal, galvanoelectric feature. The width of this feature is set by relaxation rates beyond the noninteracting magnon picture, thereby providing access to single-magnon lifetimes within the multi-magnon continuum of the response function. Moreover, the response function is shown to display various structures in the two-dimensional frequency plane related to exceptional regions of the magnon dispersion.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 7 figures
Fixed Point Stability Switches from Attractive to Repulsive at 2d Pomeranchuk/Stoner Instabilities via Field-Theoretical RG
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
We study an interacting two-flavor fermionic system via field-theoretical functional renormalization group (RG). Each flavor, labeled by $ \pm$ , has a dispersion of $ E^{\pm}=c k^{2\alpha}-\mu^\pm$ with tunable real exponent $ \alpha>0$ . The effective theory is parametrized by intra-flavor and inter-flavor interactions, preserving global U(1) $ \times$ U(1) symmetry, which can be enhanced to U(2). The U(2) symmetric system has a Fermi liquid phase and two possible instabilities, leading to spontaneous spatial rotational or flavor symmetry breaking, known as the Pomeranchuk and Stoner instabilities, respectively. The key discovery of this work is the following. The Stoner instability possesses an RG fixed point that preserves the U(2) symmetry. For $ \alpha<1$ , this fixed point is attractive, indicating a continuous transition. Conversely, for $ \alpha>1$ , the fixed point becomes repulsive, and without fine-tuning, there is runaway RG flow, resulting in a discontinuous transition. The U(1) $ \times$ U(1) symmetric system, with $ \mu^+\neq \mu^-$ , exhibits richer physics. This system have two Pomeranchuk instabilities. At one of them, a non-trivial RG fixed point switches its nature from attractive to repulsive as $ \alpha$ increases across $ 1$ . Notably, the runaway flow at $ \alpha>1$ results in the depletion of a Fermi surface at the transition. Collective modes in these Fermi liquids are also investigated. A universal Fermi surface deformation ratio $ \delta\mu^+/\delta\mu^-$ is predicted for $ \alpha<1$ at the instability as a continuous transition, which can be observed experimentally.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
21+7 pages
Magnetic ground state of a Jeff = 1/2 based frustrated triangular lattice antiferromagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
M. Barik, J. Khatua, Suyoung Kim, Eundeok Mun, Suheon Lee, Bassam Hitti, Gerald D. Morris, Kwang-Yong Choi, P. Khuntia
The subtle interplay between competing degrees of freedom, crystal electric fields, and spin correlations can lead to exotic quantum states in 4f ion-based frustrated magnets. We present the crystal structure, thermodynamic, and muon spin relaxation studies of the 4f ion-based frustrated magnet Ba4YbReWO12, wherein Yb3+ ions constitute a triangular lattice. The magnetic susceptibility does not show any signature of spin freezing down to 1.9 K or long-range magnetic ordering down to 0.4 K. The low-temperature Curie-Weiss fit to the inverse magnetic susceptibility data reveals a weak antiferromagnetic exchange interaction between the Jeff=1/2 state of the Yb3+ moments in the lowest Kramers doublet. The lowest Kramers ground state doublet is well separated from the first excited state with a gap of 278 K, as evidenced by our muon spin relaxation experiments that support the realization of the Jeff 1/2 state at low temperatures. The specific heat indicates a phase transition at 0.09 K, and the associated entropy release at low temperatures is consistent with that expected for the Jeff = 1/2 state. The zero-field muSR measurements show neither the signature of spin freezing nor a phase transition, at least down to 43 mK. Our results suggest the coexistence of static and slowly fluctuating moments in the ground state of this Jeff = 1/2 frustrated triangular lattice antiferromagnet. Ba4RReWO12 (R=rare earth) offers a viable platform to realize intriguing quantum states borne out of spin-orbit coupling and frustration.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Mott transition in excitonic Bose polarons
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-11 20:00 EDT
E. A. Szwed, B. Vermilyea, D. J. Choksy, Zhiwen Zhou, M. M. Fogler, L. V. Butov
For a neutral system of positive and negative charges, such as atoms in a crystal, increasing the density causes the Mott transition from bound electrons to free electrons. The density of optically generated electron-hole systems can be controlled in situ by the power of optical excitation that enables the Mott transition from excitons, the bound pairs of electrons and holes, to free electrons and holes with increasing density. These Mott transitions occur in systems of pairs of the same kind, such as atoms or excitons. However, a different type of the Mott transition can occur for Bose polarons. A Bose polaron is a mobile particle of one kind in a Bose gas of particles of another kind. For the Mott transition in polarons, the polaron states vanish with increasing density of the surrounding gas. In this paper, we present the observation of this type of the Mott transition and the measurement of the Mott transition parameter $ n_{\rm M}^{1/2} a_{\rm B}$ in 2D excitonic Bose polarons.
Quantum Gases (cond-mat.quant-gas)
Crystal fields, exchange, and dipolar interactions and noncollinear magnons of erbium oxide
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
Kian Maleki, Michael E. Flatté
We simulate the properties of magnons in erbium oxide, a noncollinear antiferromagnet, from an effective single-ion Hamiltonian, including exchange and long-range dipolar interactions. We parametrize the crystal field splitting of Er$ _2$ O$ _3$ using Steven’s operators and obtain the effective symmetry-dependent exchange constants between different erbium ions quenched by the crystal field at different symmetry sites. We apply the Holstein-Primakoff transformation to the noncollinear spin system and employ paraunitary diagonalization for the effective spin Hamiltonian. The addition of the dipolar interaction to the exchange magnon dispersion changes the magnon bands drastically. The long-range nature of the dipolar interaction provides challenges to convergence, however we find that the averaged and normalized difference in the magnon dispersion is less than an averaged factor of $ 10^{-6}$ if the dipolar interaction is included out to the fortieth nearest neighbor.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Tuning Diblock Copolymer Morphology by Adding Associative Homopolymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
Xiangyu Zhang, Jing Zong, Dong Meng
The ability to tune the microstructures formed by block copolymers using accessible physical approaches provides control for practical material applications. A common strategy involves the addition of homopolymers, which can induce morphological changes through their preferential partitioning into specific microdomains. More recently, supramolecular interactions - being chemistry-specific and stimuli-responsive - have emerged as powerful tools for enabling switchable morphologies. To gain microscopic insight into this process, we present a simulation study of diblock copolymers blended with homopolymers that selectively associate with one of the blocks via reversible associations. By varying the mode of association, we examine the structural changes induced by supramolecular complexation and compare them with those arising from Van der Waals (VDW) interactions. Our results reveal that, despite exhibiting similar levels of homopolymer partitioning, the lamellar structures differ significantly between the association-driven system and the VDW driven system. Cluster analysis indicates that only small clusters form at weak association strength, whereas a continuous network emerges under strong association conditions. Dynamic analysis further indicates that both morphology and supramolecular binding kinetics significantly influence the diffusion of homopolymers across microdomains, highlighting the material’s potential responsiveness to external stimuli.
Soft Condensed Matter (cond-mat.soft)
The dynamical role of optical phonons and sub-lattice screening in a solid-state ion conductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Kim H. Pham, Vijaya Begum-Hudde, Amy K. Lin, Natan A. Spear, Jackson McClellan, Michael W. Zuerch, Andre Schliefe, Kimberly A. See, Scott Cushing
Solid-state electrolytes (SSEs) require ionic conductivities that are competitive with liquid electrolytes to realize applications in all-solid state batteries. Although numerous materials have been discovered, the underlying mechanisms enabling superionic conduction remain elusive. In particular, the role of ultrafast lattice dynamics in mediating ion migration, which involves couplings between ions, phonons, and electrons, is rarely explored experimentally at their corresponding timescales. To investigate the contributions of coupled lattice dynamics on ion migration, we modulate the charge density occupations within the crystal, and then measure the time-resolved change in impedance on picosecond timescales for a candidate SSE, Li0.5La0.5TiO3. Upon perturbation, we observe enhanced ion migration at ultrafast timescales that are shorter than laser-induced heating. The respective transients match the timescales of optical and acoustic phonon vibrations, suggesting their involvement in ion migration. We further computationally evaluate the effect of a charge transfer from the O 2p to Ti 3d band on the electronic and physical structure of LLTO. We hypothesize that the charge transfer excitation distorts the TiO6 polyhedra by altering the local charge density occupancy of the hopping site at the migration pathway saddle point, thereby causing a reduction in the migration barrier for the Li+ hop, shown using computation. We rule out the contribution of photogenerated electrons and laser heating. Overall, our investigation introduces a new spectroscopic tool to probe fundamental ion hopping mechanisms transiently at ultrafast timescales, which has previously only been achieved in a time-averaged manner or solely via computational methods. Our proposed technique expands our capability to answer dynamical questions previously limited by incumbent spectroscopic strategies.
Materials Science (cond-mat.mtrl-sci)
7 figures, 1 table
Magnetic excitations in Nd${n+1}$Ni${n}$O$_{3n+1}$ Ruddlesden-Popper nickelates observed via resonant inelastic x-ray scattering
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Sophia F. R. TenHuisen, Grace A. Pan, Qi Song, Denitsa R. Baykusheva, Dan Ferenc Segedin, Berit H. Goodge, Hanjong Paik, Jonathan Pelliciari, Valentina Bisogni, Yanhong Gu, Stefano Agrestini, Abhishek Nag, Mirian García-Fernández, Ke-Jin Zhou, Lena F. Kourkoutis, Charles M. Brooks, Julia A. Mundy, Mark P. M. Dean, Matteo Mitrano
Magnetic interactions are thought to play a key role in the properties of many unconventional superconductors, including cuprates, iron pnictides, and square-planar nickelates. Superconductivity was also recently observed in the bilayer and trilayer Ruddlesden-Popper nickelates, whose electronic structure is expected to differ from that of cuprates and square-planar nickelates. Here we study how electronic structure and magnetic interactions evolve with the number of layers, $ n$ , in thin film Ruddlesden-Popper nickelates Nd$ _{n+1}$ Ni$ _{n}$ O$ _{3n+1}$ with $ n=1,:3$ , and 5 using resonant inelastic x-ray scattering (RIXS). The RIXS spectra are consistent with a high-spin $ |3d^8 \underline{L} \rangle$ electronic configuration, resembling that of La$ _{2-x}$ Sr$ _x$ NiO$ _4$ and the parent perovskite, NdNiO$ _3$ . The magnetic excitations soften to lower energy in the structurally self-doped, higher-$ n$ films. Our observations confirm that structural tuning is an effective route for altering electronic properties, such as magnetic superexchange, in this prominent family of materials.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
main + SM: 18 pages, 12 figures
Flow-driven Stretch Fluctuations Cause Anomalous Rate-Thinning In Elongating Associative Polymers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
Songyue Liu, Thomas C. O’Connor
We use nonequilibrium molecular dynamics simulations to verify recent tube-model predictions that associative polymer networks exhibit broad stretch fluctuations during elongational flow. Simulations further show that these fluctuating dynamics give rise to the rate-dependent extensional viscosity $ \eta_E$ measured in filament stretching experiments on H-bonding networks. Simulations model bivalent associative networks with a reactive bead-spring model for varying association strength and extensional strain rate. We observe that stretch fluctuations are driven by a new form of chain tumbling, where chains continually collapse and elongate as their associations break and reform within the convecting network. This produces a broad, nearly uniform distribution of chain stretch over a wide range of strain rates, manifesting as a rate-independent plateau in the extensional stress. Our results show that the nonlinear viscoelasticity of associative networks is dominated by large fluctuations in molecular response, which cannot be captured by current mean-field models.
Soft Condensed Matter (cond-mat.soft)
Small-Cell-Based Fast Active Learning of Machine Learning Interatomic Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Zijian Meng, Hao Sun, Edmanuel Torres, Christopher Maxwell, Ryan Eric Grant, Laurent Karim Béland
Machine learning interatomic potentials (MLIPs) are often trained with on-the-fly active learning, where sampled configurations from atomistic simulations are added to the training set. However, this approach is limited by the high computational cost of ab initio calculations for large systems. Recent works have shown that MLIPs trained on small cells (1-8 atoms) rival the accuracy of large-cell models (100s of atoms) at far lower computational cost. Herein, we refer to these as small-cell and large-cell training, respectively. In this work, we iterate on earlier small-cell training approaches and characterize our resultant small-cell protocol. Potassium and sodium-potassium systems were studied: the former, a simpler system benchmarked in detail; the latter, a more complex binary system for further validation. Our small-cell training approach achieves up to two orders of magnitude of cost savings compared to large-cell (54-atom) training, with some training runs requiring fewer than 120 core-hours. Static and thermodynamic properties predicted using the MLIPs were evaluated, with small-cell training in both systems yielding strong ab initio agreement. Small cells appear to encode the necessary information to model complex large-scale phenomena–solid-liquid interfaces, critical exponents, diverse concentrations–even when the training cells themselves are too small to accommodate these phenomena. Based on these tests, we provide analysis and recommendations.
Materials Science (cond-mat.mtrl-sci)
19 pages, 15 figures. Pre-print with appendices and supplementary information
Advanced measurement techniques in quantum Monte Carlo: The permutation matrix representation approach
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-11 20:00 EDT
In a typical finite temperature quantum Monte Carlo (QMC) simulation, estimators for simple static observables such as specific heat and magnetization are known. With a great deal of system-specific manual labor, one can sometimes also derive more complicated non-local or even dynamic observable estimators. Within the permutation matrix representation (PMR) flavor of QMC, however, we show that one can derive formal estimators for arbitrary static observables. We also derive exact, explicit estimators for general imaginary-time correlation functions and non-trivial integrated susceptibilities thereof. We demonstrate the practical versatility of our method by estimating various non-local, random observables for the transverse-field Ising model on a square lattice.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
33 pages, 3 figures, 2 tables
GPR_calculator: An On-the-Fly Surrogate Model to Accelerate Massive Nudged Elastic Band Calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Isaac Onyango, Byungkyun Kang, Qiang Zhu
We present GPR_calculator, a package based on Python and C++ programming languages to build an on-the-fly surrogate model using Gaussian Process Regression (GPR) to approximate expensive electronic structure calculations. The key idea is to dynamically train a GPR model during the simulation that can accurately predict energies and forces with uncertainty quantification. When the uncertainty is high, the expensive electronic structure calculation is performed to obtain the ground truth data, which is then used to update the GPR model. To illustrate the power of GPR_calculator, we demonstrate its application in Nudged Elastic Band (NEB) simulations of surface diffusion and reactions, achieving 3-10 times acceleration compared to pure ab initio calculations. The source code is available at this https URL.
Materials Science (cond-mat.mtrl-sci)
11 pages, 6 figures
Capturing the Demon in Szilard’s Engine
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-11 20:00 EDT
Xiangjun Xing (Shanghai Jiao Tong University, Shanghai 200240, China)
In Szilard’s engine, a demon measures a one-particle gas and applies feedback to extract work from thermal fluctuations, embodying Maxwell’s notion that information reduces thermodynamic entropy - an apparent second-law violation. The Landauer-Bennett Thesis resolves this paradox by requiring the demon to record the measurement, which results in an entropy increase in the demon’s memory. Eventually, the demon’s memory needs to be erased. The erasure costs the same work as extracted previously, hence there is no violation of the second law. Though widely accepted, the fictitious memory invoked in the thesis has drawn multiple criticisms, with debates persisting over the demon’s necessity. We show that the demon is the piston that partitions the space and drives the expansion. The final position of the piston after expansion records the particle’s position pre-expansion: it is an ``information-bearing degree of freedom’’. In this Piston-Demon Thesis, memory register and feedback (expansion) happen simultaneously. Our exposition identifies the mischievous demon as a physical degree of freedom, and greatly simplifies Szilard’s engine. It also offers educators a tangible illustration of information-thermodynamics.
Statistical Mechanics (cond-mat.stat-mech), Physics Education (physics.ed-ph), Popular Physics (physics.pop-ph)
10 pages, 2 figures
Exact lattice summations for Lennard-Jones potentials coupled to a three-body Axilrod-Teller-Muto term applied to cuboidal phase transitions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Andres Robles-Navarro, Shaun Cooper, Andreas A. Buchheit, Jonathan Busse, Antony Burrows, Odile Smits, Peter Schwerdtfeger
This work provides a rigorous analysis of Bain-type cuboidal lattice transformations, which connect the face-centered cubic (fcc), mean-centered cubic (mcc), body-centered cubic (bcc) and axially centered cubic (acc) lattices. Our study incorporates a general $ (n,m)$ Lennard-Jones two-body potential and a long-range repulsive Axilrod-Teller-Muto (ATM) three-body potential. The two-body lattice sums and their meromorphic continuations are evaluated to full precision using super-exponentially convergent series expansions. Furthermore, we introduce a novel approach to computing three-body lattice sums by converting the multi-dimensional sum into an integral involving products of Epstein zeta functions. This enables us to evaluate three-body lattice sums and their meromorphic continuations to machine precision within minutes on a standard laptop. Using our computational framework, we analyze the stability of cuboidal lattice phases relative to the close-packed fcc structure along a Bain transformation path for varying ATM coupling strengths. We analytically demonstrate that the ATM cohesive energy exhibits an extremum at the bcc phase and show numerically that it corresponds to a minimum for repulsive three-body forces along the Bain path. Our results indicate that strong repulsive three-body interactions can destabilize the fcc phase and render bcc energetically favorable for soft LJ potentials. However, even in this scenario, the bcc phase remains susceptible to further cuboidal distortions. These results suggest that the stability of the bcc phase is, besides vibrational, temperature, and pressure effects, strongly influenced by higher than two-body forces. Because of the wrong short-range behavior of the triple-dipole ATM model the LJ potential is limited to exponents $ n>9$ for the repulsive wall, otherwise one observes distortion into a set of linear chains collapsing to the origin.
Materials Science (cond-mat.mtrl-sci)
Cryogenic-temperature Grain-to-grain Epitaxial Growth of High-quality Ultrathin CoFe Layer on MgO Tunnel Barrier for High-performance Magnetic Tunnel Junctions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Tomohiro Ichinose, Tatsuya Yamamoto, Takayuki Nozaki, Kay Yakushiji, Shingo Tamaru, Shinji Yuasa
One candidate for ultimate non-volatile memory with ultralow power consumption is magneto-resistive random-access memory (VC-MRAM). To develop VC-MRAM, it is important to fabricate high-performance magnetic tunnel junctions (MTJs), which require the epitaxial growth of an ultrathin ferromagnetic electrode on a crystalline tunnel barrier using a mass-manufacturing-compatible process. In this study, the grain-to-grain epitaxial growth of perpendicularly magnetized CoFe ultrathin films on polycrystalline MgO (001) was demonstrated using cryogenic-temperature sputtering on 300 mm Si wafers. Cryogenic-temperature sputtering at 100 K suppressed the island-like initial growth of CoFe on MgO without hampering epitaxy. Sub-nanometer-thick CoFe layers exhibited remarkable perpendicular magnetic anisotropy (PMA). An even larger PMA was obtained using an Fe-doped MgO (MgFeO) tunnel barrier owing to improved uniformity of the CoFe layer. A 0.8-nm-thick CoFe layer grown on MgFeO exhibited a magnetic damping constant as low as 0.008. The ultralow magnetic damping enables voltage-driven magnetization switching with a low write-error rate (WER) below 10^-6 at a pulse duration of 0.3 ns, and WER on the order of 10^-3 even for a relatively long pulse duration of 1.5 ns. These properties achieved using a mass-manufacturing deposition process can promote the development of VC-MRAM and other advanced spintronic devices based on MTJs.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
under review in NPG Asia Mater
Orientational ordering in active nematic solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
Haiqian Yang, Ming Guo, L. Mahadevan
In vivo and in vitro systems of cells and extra-cellular matrix (ECM) systems are well known to form ordered patterns of orientationally aligned fibers. Here, we interpret them as active analogs of the (disordered) isotropic to the (ordered) nematic phase transition seen in passive liquid crystalline elastomers. A minimal theoretical framework that couples cellular activity (embodied as mechanical stress) and the finite deformation elasticity of liquid crystal elastomers sets the stage to explain these patterns. Linear stability analysis of the governing equations about simple homogeneous isotropic base states shows how the onset of periodic morphologies depends on the activity, elasticity, and applied strain, provides an expression for the wavelength of the instability, and is qualitatively consistent with observations of cell-ECM experiments. Finite element simulations of the nonlinear problem corroborate the results of linear analysis. These results provide quantitative insights into the onset and evolution of nematic order in cell-matrix composites.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Ultrahigh room-temperature hole conductivity in a perovskite cuprate with vanishing electron-correlation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Meng Wang, Jianbing Zhang, Liang Si, Sijie Wu, Caiyong Li, Wenfeng Wu, Xiaodong Zhang, Cong Li, Lu Wang, Fachao Li, Lingzhi Wen, Yang Liu, Jinling Zhou, Masahiro Sawada, Nianpeng Lu, Qing He, Peng Gao, Tian Liang, Shuyun Zhou, Yeliang Wang, Fumitaka Kagawa, Pu Yu
Electron-correlated two-dimensional (2D) cuprates have been extensively studied since the discovery of high-Tc superconductivity, in contrast, the three-dimensional (3D) counterpart perovskite cuprates remain largely unexplored due to their chemical instability and synthesis challenges. Herein, we develop an efficient two-step approach that combines symmetry-selective growth and topotactic oxidization to synthesize high-quality perovskite LaCuO3 films, and furthermore reveal its exotic electronic states. The compressively strained LaCuO3 films exhibit an unexpected ultrahigh p-type conductivity of ~1.5\ast10^5 S/cm with a hole mobility of ~30 cm2 V-1 s-1 at room-temperature. X-ray absorption spectra and first-principles calculations unveil a ligand-hole state of p-d hybridization with degenerate eg orbitals and light effective mass, indicating nearly-vanishing electron-correlation. These features contrast sharply with 2D cuprates and offer physical insights into the design of high-performance electronic devices.
Strongly Correlated Electrons (cond-mat.str-el)
5 figures
Structure-Property Relationship in Disordered Hyperuniform Materials: Microstructure Representation, Field Fluctuations and Effective Properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Liyu Zhong, Sheng Mao, Yang Jiao
Disordered hyperuniform (DHU) materials are an emerging class of exotic heterogeneous material systems characterized by a unique combination of disordered local structures and a hidden long-range order, which endow them with unusual physical properties. Here, we consider material systems possessing continuously varying local material properties $ \mathcal{K}({\bf x})$ modeled via a random field. We devise quantitative microstructure representation of the material systems based on a class of analytical spectral density function $ {\tilde \chi}{\mathcal{K}}({k})$ associated with $ \mathcal{K}({\bf x})$ , possessing a power-law small-$ k$ scaling behavior $ {\tilde \chi}{\mathcal{K}}({k}) \sim k^\alpha$ . By controlling the exponent $ \alpha$ and using a highly efficient forward generative model, we obtain realizations of a wide spectrum of distinct material microstructures spanning from hyperuniform ($ \alpha>0$ ) to nonhyperuniform ($ \alpha=0$ ) to antihyperuniform ($ \alpha<0$ ) systems. We perform a comprehensive perturbation analysis to quantitatively connect the fluctuations of the local material property to the fluctuations of the resulting physical fields. In the weak-contrast limit, our first-order perturbation theory reveals that the physical fields associated with Class-I hyperuniform materials (characterized by $ \alpha \ge 2$ ) are also hyperuniform, albeit with a lower hyperuniformity exponent ($ \alpha-2$ ). As one moves away from this weak-contrast limit, the fluctuations of the physical field develop a diverging spectral density at the origin. We also establish an end-to-end mapping connecting the spectral density of the local material property to the overall effective conductivity of the material system via numerical homogenization.
Materials Science (cond-mat.mtrl-sci)
17 pages, 8 figures
Evaluation of Circular Complex Permeability in Single-Crystal Yttrium Iron Garnet at Cryogenic Temperatures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Junta Igarashi, Shota Norimoto, Hiroyuki Kayano, Noriyoshi Hashimoto, Makoto Minohara, Nobu-Hisa Kaneko, Tomonori Arakawa
The operation of superconducting qubits requires a sensitive readout circuit at cryogenic temperatures, driving the demand for cryogenic non-reciprocal microwave components such as circulators. However, evaluating these components at low temperatures presents significant challenges for companies and institutions without specialized measurement systems. In the development of such cryogenic non-reciprocal components, the temperature dependence of ferrite’s magnetic properties is the most critical factor. Therefore, an evaluation technique for accurately assessing these properties at cryogenic temperatures is essential.
In this study, we develop a measurement method to characterize low-loss ferrite materials over a temperature range of 300 K to 2 K. The use of the circularly polarized resonance mode (TE11n) enables the direct estimation of circular complex permeability and the determination of key material parameters, including saturation magnetization and damping constant - both essential for assessing the performance of ferrite materials in circulator applications. Without the need for device fabrication, we demonstrate that single-crystal Yttrium Iron Garnet (YIG) can effectively function as a circulator down to 2 K. This approach offers a promising pathway for the development of cryogenic circulators.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
8 pages, 7 figures. This work has been submitted to the IEEE for possible publication
Quantifying the Phase Diagram and Hamiltonian of $S=1/2$ Kagome Antiferromagnets: Bridging Theory and Experiment
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Shengtao Jiang, Arthur C. Campello, Wei He, Jiajia Wen, Daniel M. Pajerowski, Young S. Lee, Hong-Chen Jiang
Spin-$ 1/2$ kagome antiferromagnets are leading candidates for realizing quantum spin liquid (QSL) ground states. While QSL ground states are predicted for the pure Heisenberg model, understanding the robustness of the QSL to additional interactions that may be present in real materials is a forefront question in the field. Here we employ large-scale density-matrix renormalization group simulations to investigate the effects of next-nearest neighbor exchange couplings $ J_2$ and Dzyaloshinskii-Moriya interactions $ D$ , which are relevant to understanding the prototypical kagome materials herbertsmithite and Zn-barlowite. By utilizing clusters as large as XC12 and extrapolating the results to the thermodynamic limit, we precisely delineate the scope of the QSL phase, which remains robust across an expanded parameter range of $ J_2$ and $ D$ . Direct comparison of the simulated static and dynamic spin structure factors with inelastic neutron scattering reveals the parameter space of the Hamiltonians for herbertsmithite and Zn-barlowite, and, importantly, provides compelling evidence that both materials exist within the QSL phase. These results establish a powerful convergence of theory and experiment in this most elusive state of matter.
Strongly Correlated Electrons (cond-mat.str-el)
7+2 pages, 5+3 figures
Optoelectronic properties of self-trapped holes in orthorhombic Ga2O3 and its alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Eric Welch, Lauro Guerra, Luisa Scolfaro, Luiz A. F. C. Viana, Pablo D. Borges
We investigated the influence of valence band holes on the optoelectronic properties of orthorhombic k-Ga2O3 and its alloys with Al and In. Our hybrid density functional theory calculations show that self-trapped holes (STHs) localize on oxygen atoms within a single unit cell and exhibit \emph{p}-orbital characteristics. The inclusion of isoelectronic dopants such as Al and In reduces but does not remove the absorption of visible light due to STH formation. The combination of a positive STH formation energy, large lattice distortions, and emergent acceptor levels, coupled with the observed red-shifted, visible spectrum, emergent absorption peaks, implies that alternative doping/alloying strategies are necessary to achieve effective p-type conductivity in orthorhombic k-Ga2O3.
Materials Science (cond-mat.mtrl-sci)
16 pages, 6 figures, 2 tables. Hybrid density functional theory simulations
Laboratory Three-dimensional X-ray Micro-beam Laue Diffraction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Yubin Zhang, Anthony Seret, Jette Oddershede, Azat Slyamov, Jan Kehres, Florian Bachmann, Carsten Gundlach, Ulrik Lund Olsen, Jacob Bowen, Henning Friis Poulsen, Erik Lauridsen, Dorte Juul Jensen
The development of three-dimensional (3D) non-destructive X-ray characterization techniques in home laboratories is essential for enabling many more researchers to perform 3D characterization daily, overcoming the limitations imposed by competitive and scarce access to synchrotron facilities. Recent efforts have focused on techniques such as laboratory diffraction contrast tomography (LabDCT), which allows 3D characterization of recrystallized grains with sizes larger than 15-20 $ \mu$ m, offering a boundary resolution of approximately 5$ \mu$ m using commercial X-ray computed tomography (CT) systems. To enhance the capabilities of laboratory instruments, we have developed a new laboratory-based 3D X-ray micro-beam diffraction (Lab-3D$ \mu$ XRD) technique. Lab-3D$ \mu$ XRD combines the use of a focused polychromatic beam with a scanning-tomographic data acquisition routine to enable depth-resolved crystallographic orientation characterization. This work presents the first realization of Lab-3D$ \mu$ XRD, including hardware development through the integration of a newly developed Pt-coated twin paraboloidal capillary X-ray focusing optics into a conventional X-ray $ \mu$ CT system, as well as the development of data acquisition and processing software. The results are validated through comparisons with LabDCT and synchrotron phase contrast tomography. The findings clearly demonstrate the feasibility of Lab-3D$ \mu$ XRD, particularly in detecting smaller grains and providing intragranular information. Finally, we discuss future directions for developing Lab-3D$ \mu$ XRD into a versatile tool for studying materials with smaller grain sizes and high defect densities, including the potential of combining it with LabDCT and $ \mu$ CT for multiscale and multimodal microstructural characterization.
Materials Science (cond-mat.mtrl-sci)
21 pages, 9 figures
Homogeneous nucleation rate of carbon dioxide hydrate formation under experimental condition from Seeding simulations
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
I. M. Zerón, J. Algaba, J. M. Míguez, J. Grabowska, S. Blazquez, E. Sanz, C. Vega, F. J. Blas
We investigate the nucleation of carbon dioxide (CO$ _2$ ) hydrates from carbon dioxide aqueous solutions by means of molecular dynamics simulations using the TIP4P/Ice and the TraPPE models for water and CO$ _2$ respectively. We work at 400 bar and different temperatures and CO$ _2$ concentrations. We use brute force molecular dynamics when the supersaturation or the supercooling are so high so that nucleation occurs spontaneously and Seeding otherwise. We used both methods for a particular state and we get a rate of 10$ ^{25},\text{m}^{-3}\text{s}^{-1}$ for nucleation in a CO$ _2$ saturated solution at 255 K (35 K of supercooling). By comparison with our previous work on methane hydrates, we conclude that nucleation of CO$ _2$ hydrates is several orders of magnitude faster due to a lower interfacial free energy between the crystal and the solution. By combining our nucleation studies with a recent calculation of the hydrate-solution interfacial free energy at coexistence, we obtain a prediction of the nucleation rate temperature dependence for CO$ _{2}$ -saturated solutions (the experimentally relevant concentration). On the one hand, we open the window for comparison with experiments for supercooling larger than 25 K. On the other hand, we conclude that homogeneous nucleation is impossible for supercooling lower than 20 K. Therefore, nucleation must be heterogeneous in typical experiments where hydrate formation is observed at low supercooling. To assess the hypothesis that nucleation occurs at the solution-CO$ _2$ interface we run spontaneous nucleation simulations in two-phase systems and find, by comparison with single-phase simulations, that the interface does not affect hydrate nucleation, at least at the deep supercooling at which this study was carried out (40 and 45 K). Overall, our work sheds light on molecular and thermodynamic aspects of hydrate nucleation.
Soft Condensed Matter (cond-mat.soft)
20 pages, 15 figures, 3 tables
Coexistence of topologically trivial and non-trivial Yu-Shiba-Rusinov bands in magnetic atomic chains on a superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-11 20:00 EDT
Bendegúz Nyári, Philip Beck, András Lászlóffy, Lucas Schneider, Krisztián Palotás, László Szunyogh, Roland Wiesendanger, Jens Wiebe, Balázs Újfalussy, Levente Rózsa
Majorana zero modes (MZMs) have been proposed as a promising basis for Majorana qubits offering great potential for topological quantum computation. Such modes may form at the ends of a magnetic atomic chain on a superconductor. Typically only a single MZM may be present at one end of the chain, but symmetry may protect multiple MZMs at the same end. Here, we study the topological properties of Yu-Shiba-Rusinov (YSR) bands of excitations in Mn chains constructed on a Nb(110) and on a Ta(110) substrate using first-principles calculations and scanning tunneling microscopy and spectroscopy experiments. We demonstrate that even and odd YSR states with respect to mirroring on the symmetry plane containing the chain have different dispersions, and both of them may give rise to MZMs separately. Although the spin-orbit coupling leads to a hybridization between the bands, multiple MZMs may still exist due to the mirror symmetry. These findings highlight the influence of symmetries on interpreting the spectroscopic signatures of candidates for MZMs.
Superconductivity (cond-mat.supr-con)
13 pages, 4 figures Supplementary Material: 9 pages, 6 figures
Wigner distribution, Wigner entropy, and Anomalous Transport of a Generalized Aubry-André model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-11 20:00 EDT
Feng Lu, Hailin Tan, Ao Zhou, Shujie Cheng, Gao Xianlong
In this paper, we study a generalized Aubry-André model with tunable quasidisordered potentials. The model has an invariable mobility edge that separates the extended states from the localized states. At the mobility edge, the wave function presents critical characteristics, which can be verified by finite-size scaling analysis. Our numerical investigations demonstrate that the extended, critical, and localized states can be effectively distinguished via their phase space representation, specially the Wigner distribution. Based on the Wigner distribution function, we can further obtain the corresponding Wigner entropy and employ the feature that the critical state has the maximum Wigner entropy to locate the invariable mobility edge. Finally, we reveal that there are anomalous transport phenomena between the transition from ballistic transport to the absence of diffusion.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
7 pages, 5 figures
Atomic structure analysis of PL5 in silicon carbide with single-spin spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Yu Chen, Qi Zhang, Mingzhe Liu, Jinpeng Liu, Jingyang Zhou, Pei Yu, Shaochun Lin, Yuanhong Teng, Wancheng Yu, Ya Wang, Changkui Duan, Fazhan Shi, Jiangfeng Du
Divacancy (VV) spin defects in 4H polytype of silicon carbide (4H-SiC) are emerging candidates for quantum information processing and quantum sensing. Among these defects, PL5 and PL6 stand out due to their superior charge stability and optically detected magnetic resonance (ODMR) properties at room temperature. However, their atomic structures remain unresolved, with ongoing controversy regarding their potential association with stacking faults. Previous measurements relying on spin ensemble detection are insufficient to draw definitive conclusions. In this study, we conduct correlative imaging of stacking faults and PL5-6 at single-defect level, conclusively demonstrating that PL5-6 are not associated with stacking faults. Further investigation of PL5 through single-spin ODMR spectroscopy allows us to determine its six spatial orientations, as well as to measure the orientation of its transverse anisotropy spin splitting (E) and the statistical distribution of hyperfine splitting. These results and ab initio calculations suggest that PL5 should be VsiVc(hk) divacancy coupled with a nearby antisite atom (VVA). The structure resolution of PL5 starts the first step toward its controllable fabrication, paving the way for various applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
6 pages, 5 figures
Tuning chirality amplitude at ultrafast timescales
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Hiroki Ueda, Takahiro Sato, Quynh L. Nguyen, Elizabeth Skoropata, Ludmila Leroy, Tim Suter, Elsa Abreu, Matteo Savoini, Vincent Esposito, Matthias Hoffmann, Carl P. Romao, Julien Zaccaro, Diling Zhu, Steven Lee Johnson, Urs Staub
Chirality is a fundamental symmetry concept describing discrete states, i.e., left-handed, right-handed, or achiral, and existing at disparate scales and in many categories of scientific fields. Even though symmetry breaking is indispensable for describing qualitatively distinct phenomena, symmetry cannot quantitatively predict measurable quantities. One can continuously distort an object, introducing the concept of chirality amplitude, similar to representing magnetization as the amplitude of time-reversal symmetry breaking. Considering the role of magnetization in emergent phenomena with time-reversal symmetry breaking, chirality amplitude is intuitively a key quantity for controlling chirality-related emergent phenomena. Here, we propose two types of chiral lattice distortions and demonstrate the tunability of their amplitude in ultrafast timescales. Resonant X-ray diffraction with circular polarization is an established technique to measure crystal chirality directly. We quantify the ultrafast change in chirality amplitude in real time after an optical excitation. Using instead a THz excitation, we observe oscillations in the resonant diffraction intensities corresponding to specific phonon frequencies. This indicates the creation of additional asymmetry, which could also be described as an enhancement in chirality amplitude. Our proposed concept of chirality amplitude and its ultrafast control may lead to a unique approach to control chirality-induced emergent phenomena in ultrafast timescales.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 5 figures
Enhanced THz emission from spintronic emitters with Pt-Al alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Felix Janus, Nicolas Beermann, Jyoti Yadav, Reshma Rajeev Lekha, Wentao Zhang, Hassan A. Hafez, Dmitry Turchinovich, Markus Meinert
Platinum (Pt) is the element with the largest spin Hall conductivity and is known as the most efficient spin-to-charge conversion material in spintronic THz emitters. By alloying with aluminum (Al), its resistivity can be substantially increased, exceeding $ 100,\mu\Omega$ cm. While the spin Hall conductivity is reduced by alloying, the relative resistivity increase surpasses the reduction of spin Hall conductivity and thereby enhances the spin Hall angle. We make use of this mechanism to improve the commonly used Pt-based spintronic THz emitter and demonstrate that an increase of 67% in the THz emission amplitude can be achieved between 20% and 30% Al in Pt. We show that the enhanced THz emission amplitude is driven by the enhanced multilayer impedance due to the larger resistivity.
Materials Science (cond-mat.mtrl-sci)
4 pages, 3 figures
Quasi-rigid-band behavior and band gap changes upon isovalent substitution in Cs$_3$Bi$2$Br${9-x}$I$_x$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
The recently introduced approach, combining the parameter-free Armiento-Kümmel generalized gradient approximation exchange functional with the nonseparable gradient approximation Minnesota correlation functional, was used to calculate the electronic structure of the Cs$ _3$ Bi$ _2$ Br$ _{9-x}$ I$ _x$ series within density functional theory including the spin-orbit coupling. The changes in the band gap size and its dependence on the $ x$ value was investigated. The band gap was found to be of indirect nature and it decreases with increasing I content as long as the system is in the $ P\overline{3}m1$ phase. A clear non-linear dependence of the band gap size on $ x$ was established which is in qualitative and quantitative agreement with reported experimental data. The quasi-rigid band behavior of the states in the valence and conduction bands of the $ P\overline{3}m1$ phase is discussed since no significant changes in the shape of the total density of unoccupied states were observed upon the isovalent substitution.
Materials Science (cond-mat.mtrl-sci)
Nonperturbative quantum theory of multiplasmonic electron emission from surfaces: Gauge-specific cumulant expansions vs. Volkov ansatz over plasmonic coherent states
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Energetic electromagnetic fields produce a variety of elementary excitations in solids that can strongly modify their primary photoemission spectra. Such is the plasmon excitation or pumping mechanism which, although indirect, is very efficient and hence may give rise to formation of plasmonic coherent states. In turn, these states may act as a source or sink of energy and momentum for escaping electrons. Starting from the model Hamiltonian approach we show that prepumped plasmonic bath of coherent states gives rise to ponderomotive potentials and Floquet electronic band structure that support multiple plasmon-induced electron emission or plasmoemission from metals. Theoretical description of multiple plasmoemission requires a nonperturbative approch which is here formulated by applying cumulant expansion and Volkov ansatz to the calculations of electron wavefunctions and emission rates. The calculations are performed in the standard length gauge as well as in the Pauli-transformed velocity gauge for electron-plasmon interaction. The applicability of two nonperturbative approaches to calculation of excitation amplitudes are examined in each gauge. They smoothly interpolate between the fully quantal first order Born approximation and semiclassical multiplasmon-induced electron excitation limit. This is illustrated on the example of plasmoemission from Floquet surface bands on Ag(111) from which this channel of electron yield has been detected. Our calculations indicate that even subsingle mode occupations of plasmonic coherent states can support multiplasmon electron emission from surface bands. A way of calibration of plasmonic coherent states is proposed.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Comments are welcome
Chirality-induced selectivity of angular momentum by orbital Edelstein effect in carbon nanotubes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
Börge Göbel, Ingrid Mertig, Samir Lounis
Carbon nanotubes (CNTs) are promising materials exhibiting exceptional strength, electrical conductivity, and thermal properties, making them promising for various technologies. Besides achiral configurations with a zigzag or armchair edge, there exist chiral CNTs with a broken inversion symmetry. Here, we demonstrate that chiral CNTs exhibit chirality-induced orbital selectivity (CIOS), which is caused by the orbital Edelstein effect and could be detected as chirality-induced spin selectivity (CISS). We find that the orbital Edelstein susceptibility is an odd function of the chirality angle of the nanotube and is proportional to its radius. For metallic CNTs close to the Fermi level, the orbital Edelstein susceptibility increases quadratically with energy. This makes the CISS and CIOS of metallic chiral nanotubes conveniently tunable by doping or applying a gate voltage, which allows for the generation of spin- and orbital-polarized currents. The possibility of generating large torques makes chiral CNTs interesting candidates for technological applications in spin-orbitronics and quantum computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 5 figures. This work was supported by the EIC Pathfinder OPEN grant 101129641 Orbital Engineering for Innovative Electronics
Role of activity and dissipation in achieving precise beating in cilia: Insights from the rower model
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
Subhajit Gupta, Debasish Chaudhuri, Supravat Dey
Cilia and flagella are micron-sized filaments that actively beat with remarkable precision in a viscous medium, driving microorganism movement and efficient flow. We study the rower model to uncover how cilia activity and dissipation enable this precise motion. In this model, cilia motion is represented by a micro-beads Brownian movement between two distant harmonic potentials. At specific locations, energy pumps trigger potential switches, capturing cilia activity and generating oscillations. We quantify precision of oscillation using a quality factor, identifying its scaling with activity and oscillation amplitude, finding precision maximization at an optimal amplitude. The data collapse is not accurate for noisy oscillations. An exact analytic expression for the precision quality factor, based on first passage time fluctuations, and derived in the small noise approximation, explains its optimality and scaling. Energy budget analysis shows the quality factor’s consistency with the thermodynamic uncertainty relation.
Soft Condensed Matter (cond-mat.soft)
10 pages, 5 figures
Hallmarks of terahertz magnon currents in an antiferromagnetic insulator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
Hongsong Qiu, Oliver Franke, Yuanzhe Tian, Zdeněk Kašpar, Reza Rouzegar, Oliver Gueckstock, Ji Wu, Maguang Zhu, Biaobing Jin, Yongbing Xu, Tom S. Seifert, Di Wu, Piet W. Brouwer, Tobias Kampfrath
The efficient transport of spin angular momentum is expected to play a crucial role in future spintronic devices, which potentially operate at frequencies reaching the terahertz range. Antiferromagnetic insulators exhibit significant potential for facilitating ultrafast pure spin currents by terahertz magnons. Consequently, we here use femtosecond laser pulses to trigger ultrafast spin currents across antiferromagnetic NiO thin films in Py|NiO|Pt stacks, where permalloy (Py) and Pt serve as spin-current source and detector respectively. We find that the spin current pulses traversing NiO reach a velocity up to 40 nm/ps and experience increasing delay and broadening as the NiO thickness is increased. We can consistently explain our observations by ballistic transport of incoherent magnon. Our approach has high potential to characterize terahertz magnon transport in magnetic insulators with any kind of magnetic order.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Effects of Berry Curvature and Orbital Magnetic Moment in the Magnetothermoelectric Transport of Bloch Electron Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
Thermoelectric transport coefficients up to linear order in the applied magnetic field are microscopically studied using Kubo-Luttinger linear response theory and thermal Green’s functions. We derive exact formulas for the thermoelectric conductivity and thermal conductivity in the limit of small relaxation rates for Bloch electrons in terms of Bloch wave functions, which show that the Sommerfeld-Bethe relationship holds. Our final formula contains the Berry curvature contributions as well as the orbital magnetic moment contributions, that arise naturally from the microscopic theory. We show that generalized $ f$ -sum rules containing the Berry curvature and orbital magnetic moment play essential roles in taking into account the interband effects of the magnetic field. As an application, we study a model of a gapped Dirac electron system with broken time-reversal symmetry and show the presence of a linear magnetothermopower in such systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Magnetic polarons at finite temperature: One-hole spectroscopy study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Toni Guthardt, Markus Scheb, Jan von Delft, Annabelle Bohrdt, Fabian Grusdt
The physics of strongly correlated fermions described by Hubbard or $ t$ -$ J$ models in the underdoped regime – relevant for high-temperature superconductivity in cuprate compounds – remains a subject of ongoing debate. In particular, the nature of charge carriers in this regime is poorly understood, in part due to the unusual properties of their spectral function. In this Letter, we present unbiased numerical results for the one-hole spectral function in a $ t$ -$ J$ model at finite temperatures. Our study provides valuable insights into the underlying physics of magnetic (or spin-) polaron formation in a doped antiferromagnet (AFM). For example, we find how the suppression of spectral weight outside the magnetic Brillouin zone – a precursor of Fermi arc formation – disappears with increasing temperature, revealing nearly-deconfined spinon excitations of the undoped AFM. The pristine setting we consider can be directly explored using quantum simulators. Our calculations demonstrate that coherent quasiparticle peaks associated with magnetic polarons can be observed up to temperatures $ T>J$ above the spin-exchange $ J$ , routinely obtained in such experiments. This paves the way for future studies of the fate of magnetic polarons in the pseudogap phase.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas)
Finite-temperature real-time properties of magnetic polarons in two-dimensional quantum antiferromagnets
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-11 20:00 EDT
Toni Guthardt, Markus Scheb, Jan von Delft, Fabian Grusdt, Annabelle Bohrdt
Due to significant progress in quantum gas microscopy in recent years, there is a rapidly growing interest in real-space properties of single mobile dopands created in correlated antiferromagnetic (AFM) Mott insulators. However, a detailed numerical description remains challenging, even for simple toy models. As a consequence, previous numerical simulations for large systems were largely limited to $ T=0$ . To provide guidance for cold-atom experiments, numerical calculations at finite temperature are required. Here, we numerically study the real-time properties of a single mobile hole in the 2D $ t$ -$ J$ model at finite temperature and draw a comparison to features observed at $ T=0$ . We find that a three-stage process of hole motion, which was reported at $ T=0$ , is valid even at finite temperature. However, already at low temperatures, the average hole velocity at long times is not simply proportional to the spin coupling, contrary to the $ T=0$ behavior. Comparing our finite-temperature numerical results with the experimental data from quantum gas microscopy we find a qualitative disagreement: in experiment, hole spreading speeds up with increasing $ J/t$ , while in our numerics it slows down. The latter is consistent with the numerical findings previously reported at $ T=0$ .
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el)
Statistics of power and efficiency for collisional Brownian engines
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-11 20:00 EDT
Gustavo A. L. Forão, Fernando S. Filho, Pedro V. Paraguassú
Collisional Brownian engines have attracted significant attention due to their simplicity, experimental accessibility, and amenability to exact analytical solutions. While previous research has predominantly focused on optimizing mean values of power and efficiency, the joint statistical properties of these performance metrics remain largely unexplored. Using stochastic thermodynamics, we investigate the joint probability distributions of power and efficiency for collisional Brownian engines, revealing how thermodynamic fluctuations influence the probability of observing values exceeding their respective mean maxima. Our conditional probability analysis demonstrates that when power fluctuates above its maximum mean value, the probability of achieving high efficiency increases substantially, suggesting fluctuation regimes where the classical power-efficiency trade-off can be probabilistically overcome. Notably, our framework extends to a broader class of engines, as the essential features of the statistics of the system are fully determined by the Onsager coefficients. Our results contribute to a deeper understanding of the role of fluctuations in Brownian engines, highlighting how stochastic behavior can enable performance beyond traditional thermodynamic bounds.
Statistical Mechanics (cond-mat.stat-mech)
12 pages, 6 figures
Antiferromagnetic Chiral Bobber Formation and Topological Proximity Effect in MnBi2Te4
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
Y. Xu, D. Kurebayashi, D. Zhang, P. Schoenherr, L. Li, Z. Yue, W. J. Ren, M.-G. Han, Y. Zhu, Z. Cheng, X. Wang, Oleg A. Tretiakov, J. Seidel
With topological materials being billed as the key to a new generation of nanoelectronics via either functional real-space topological structures (domain walls, skyrmions etc.) or via momentum-space topology (topological insulators), tailored and controllable topological properties are of paramount significance, since they lead to topologically protected states with negligible dissipation, enabling stable and non-volatile information processing. Here, we report on the evolution of topological magnetic textures in the proximity of other topological defects, i.e., antiferromagnetic domain walls in the topological insulator MnBi2Te4. The transition from the antiferromagnetic ground state to a canted antiferromagnetic state at finite magnetic fields is accompanied by the formation of chiral bobbers - bulk-terminated topological defects adjacent to the domain walls in this system, leading to a topological proximity effect.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
14 pages, 9 figures
Monitored quantum transport: full counting statistics of a quantum Hall interferometer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
We generalize the Levitov-Lesovik formula for the probability distribution function of the electron charge transferred through a phase coherent conductor, to include projective measurements that monitor the chiral propagation in quantum Hall edge modes. When applied to an electronic Mach-Zehnder interferometer, the monitoring reduces the visibility of the Aharonov-Bohm conductance oscillations while preserving the binomial form of the counting statistics, thereby removing a fundamental shortcoming of the dephasing-probe model of decoherence.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 2 figures
Active Matter Flocking via Predictive Alignment
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
Julian Giraldo-Barreto, Viktor Holubec
Understanding collective self-organization in active matter, such as bird flocks and fish schools, remains a grand challenge in physics. Alignment interactions are essential for flocking, yet alone, they are generally considered insufficient to maintain cohesion against noise, forcing traditional models to rely on artificial boundaries or added attractive forces. Here, we report the first model to achieve cohesive flocking using purely alignment interactions, introducing predictive alignment: agents orient based on the predicted future headings of their neighbors. Implemented in a discrete-time Vicsek-type framework, this approach delivers robust, noise-resistant cohesion without additional parameters. In the stable regime, flock size scales linearly with interaction radius, remaining nearly immune to noise or propulsion speed, and the group coherently follows a leader under noise. These findings reveal how predictive strategies enhance self-organization, paving the way for a new class of active matter models blending physics and cognitive-like dynamics.
Soft Condensed Matter (cond-mat.soft), Adaptation and Self-Organizing Systems (nlin.AO)
10 pages, 5 figures
Interference-caged quantum many-body scars: the Fock space topological localization and interference zeros
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
We propose a general mechanism for realizing athermal finite-energy-density eigenstates – termed interference-caged quantum many-body scars (ICQMBS) – which originate from exact many-body destructive interference on the Fock space graph. These eigenstates are strictly localized to specific subsets of vertices, analogous to compact localized states in flat-band systems. Central to our framework is a connection between interference zeros and graph automorphisms, which classify vertices according to the graph’s local topology. This connection enables the construction of a new class of topological ICQMBS, whose robustness arises from the local topology of the Fock space graph rather than from conventional conservation laws or dynamical constraints. We demonstrate the effectiveness of this framework by developing a graph-theory-based search algorithm, which identifies ICQMBS in both a one-dimensional spin-1 XY model and two-dimensional quantum link models across distinct gauge sectors. In particular, we discover the proposed topological ICQMBS in the two-dimensional quantum link model and provide an intuitive explanation for previously observed order-by-disorder phenomena in Hilbert space. Our results reveal an unexpected synergy between graph theory, flat-band physics, and quantum many-body dynamics, offering new insights into the structure and stability of nonthermal eigenstates.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
51 pages, 23 figures
Atomic Regional Superfluids in two-dimensional Moiré Time Crystals
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-11 20:00 EDT
Weijie Liang, Weiping Zhang, Keye Zhang
Moiré physics has transcended spatial dimensions, extending into synthetic domains and enabling novel quantum phenomena. We propose a theoretical model for a two-dimensional (2D) Moiré time crystal formed by ultracold atoms, induced by periodic perturbations applied to a non-lattice trap. Our analysis reveals the emergence of regional superfluid states exhibiting moiré-scale quantum coherence across temporal, spatial, and spatiotemporal domains. This work provides fundamental insights into temporal moiré phenomena and presents an alternative pathway to engineer spatial moiré phases without requiring twisted multilayer lattices.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Electronic structure of fullerene nanoribbons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Using first-principles calculations, we examine the electronic structure of quasi-one-dimensional fullerene nanoribbons derived from two-dimensional fullerene networks. Depending on the edge geometry and width, these nanoribbons exhibit a rich variety of properties, including direct and indirect band gaps, positive and negative effective masses, as well as dispersive and flat bands. Our findings establish a comprehensive understanding of the electronic properties of fullerene nanoribbons, with potential implications for the design of future nanoscale devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Atomic and Molecular Clusters (physics.atm-clus), Chemical Physics (physics.chem-ph)
9 pages, 5 figures
Mechanical Amorphization of Glass-Forming Systems Induced by Oscillatory Deformation: The Energy Absorption and Efficiency Control
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
Baoshuang Shang, Xinxin Li, Pengfei Guan, Weihua Wang
The kinetic process of mechanical amorphization plays a central role in tailoring material properties. Therefore, a quantitative understanding of how this process depends on loading parameters is critical for optimizing mechanical amorphization and tuning material performance. In this study, we employ molecular dynamics simulations to investigate oscillatory deformation-induced amorphization in three glass-forming intermetallic systems, addressing two unresolved challenges: (1) the relationship between amorphization efficiency and mechanical loading, and (2) energy absorption dynamics during crystal-to-amorphous (CTA) transitions. Our results demonstrate a decoupling between amorphization efficiency–governed by work rate and described by an effective temperature model–and energy absorption, which adheres to the Herschel-Bulkley constitutive relation. Crucially, the melting enthalpy emerges as a key determinant of the energy barrier, establishing a thermodynamic analogy between mechanical amorphization and thermally induced melting. This relationship provides a universally applicable metric to quantify amorphization kinetics. By unifying material properties and loading conditions, this work establishes a predictive framework for controlling amorphization processes. These findings advance the fundamental understanding of deformation-driven phase transitions and offer practical guidelines for designing materials with tailored properties for ultrafast fabrication, ball milling, and advanced mechanical processing techniques.
Materials Science (cond-mat.mtrl-sci)
Inverse Design of Block Polymer Materials with Desired Nanoscale Structure and Macroscale Properties
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-11 20:00 EDT
The rational design of novel polymers with tailored material properties has been a long-standing challenge in the field due to the large number of possible polymer design variables. To accelerate this design process, there is a critical need to develop novel tools to aid in the inverse design process and efficiently explore the high-dimensional polymer design space. Optimizing macroscale material properties for polymeric systems is difficult as properties are dictated by features on a multitude of length scales, ranging from the chosen monomer chemistries to the chain level design to larger-scale domain structures. In this work, we present an efficient high-throughput in-silico based framework to effectively design high-performance polymers with desired multi-scale nanostructure and macroscale properties, which we call RAPSIDY 2.0 - Rapid Analysis of Polymer Structure and Inverse Design strategY 2.0. This new version of RAPSIDY builds upon our previous work, RAPSIDY 1.0, which focused purely on identifying polymer designs that stabilized a desired nanoscale morphology. In RAPSIDY 2.0 we use a combination of molecular dynamics simulations and Bayesian optimization driven active learning to optimally query high-dimensional polymer design spaces and propose promising design candidates that simultaneously stabilize a selected nanoscale morphology and exhibit desired macroscale material properties. We utilize MD simulations with polymer chains preplaced into selected nanoscale morphologies and perform virtual experiments to determine the stability of the chosen polymer design within the target morphology and calculate the desired macroscale material properties (e.g., thermal conductivity). Our methodology directly addresses the unique challenge associated with copolymers, whose macroscale properties are a function of both their chain design and mesoscale morphology, which are coupled.
Soft Condensed Matter (cond-mat.soft)
Short-range magnetic order and planar anisotropy in the topological ferrimagnet Mn3Si2Te6
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Raju Baral, Andrew F. May, Stuart Calder
Mn3Si2Te6 is a ferrimagnetic topological nodal-line semiconductor that exhibits unconventional colossal magnetoresitance (CMR) behavior, with short-range spin fluctuations being potentially intimately linked to the emergent properties. In this work, we determine the short range magnetic order and quantify the local magnetic anisotropy through total neutron scattering and polarized neutron powder diffraction (pNPD) measurements on polycrystalline Mn3Si2Te6. The real space local and long range spin structure was determined through the application of magnetic pair distribution function (mPDF) analysis, with measurements from the low temperature ordered phase to the high temperature paramagnetic state. Short-range order over a frustrated trimer of three nearest neighbors was found to exist well above the long range ferrimagnetic transition. pNPD measurements in the spin polarized paramagnetic state were used to extract the local site susceptibility tensor of the Mn ions to quantify the magnetic anisotropy. Our combined mPDF and pNPD results provide quantitative information on the short-range order intrinsic to Mn3Si2Te6, showing strong in-plane anisotropy with the spins largely confined to the ab-plane in zero field and remain stable with increasing temperature through the long-range to short-range ordered transition.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Phonon fluctuation diagnostics: Origin of charge order in AV$_3$Sb$_5$ kagome metals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Stefan Enzner, Jan Berges, Arne Schobert, Dongjin Oh, Mingu Kang, Riccardo Comin, Ronny Thomale, Tim O. Wehling, Domenico Di Sante, Giorgio Sangiovanni
The microsopic origin of the charge-density wave (CDW) in AV$ _3$ Sb$ _5$ (A = K, Rb, Cs) kagome metals remains a longstanding question, often revolving around electron-phonon coupling and purely electronic mechanisms involving Van Hove scenarios, nesting, and sublattice interference. To reveal the processes driving the CDW transition, we combine ab-initio calculations analysis of the phonon self-energy and angle-resolved photoemission spectroscopy (ARPES). Our momentum-resolved study, supported by ARPES data, reveals that lattice instabilities in the V-135 family of kagome metals appear to also be driven by electronic states far from high-symmetry points, where these states exhibit the strongest coupling with the phonon modes responsible for the CDW distortion. Footing on an interpretation scheme based on phonon fluctuation diagnostics, our work challenges and revises theories that so far have exclusively attributed CDW formation to nesting effects close to the Fermi level.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
13 pages, 11 figures
Dislocation Patterning as a Mechanism for Flat Band Formation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
We compute the second-order correction to the electronic dispersion relation of a free electron gas interacting with an effective electron-dislocation potential, derived from a modern quantized theory of dislocations. Our results demonstrate that dislocation patterning induces anisotropic flat bands in the electronic dispersion under specific strain fields and directions, referred to as ``magic’’ parameters. These flat bands acquire non-zero curvature as the strain or direction deviates from these magic parameters.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Physical Review B111,155116(2025)
Spectral delineation of Markov Generators: Classical vs Quantum
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-11 20:00 EDT
Dariusz Chruściński, Sergey Denisov, Wojciech Tarnowski, Karol Życzkowski
The celebrated theorem of Perron and Frobenius implies that spectra of classical Markov operators, represented by stochastic matrices, are restricted to the unit disk. This property holds also for spectra of quantum stochastic maps (quantum channels), which describe quantum Markovian evolution in discrete time. Moreover, the spectra of stochastic $ N \times N$ matrices are additionally restricted to a subset of the unit disk, called Karpeleviuc region, the shape of which depends on $ N$ . We address the question of whether the spectra of generators, which induce Markovian evolution in continuous time, can be bound in a similar way. We propose a rescaling that allows us to answer this question affirmatively. The eigenvalues of the rescaled classical generators are confined to the modified Karpeleviuc regions, whereas the eigenvalues of the rescaled quantum generators fill the entire unit disk.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Hydrodynamic Coulomb drag in odd electron liquids
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
Dmitry Zverevich, Dmitri B. Gutman, Alex Levchenko
We consider the problem of Coulomb drag resistance in bilayers of electron liquids with spontaneously broken time-reversal symmetry. In the hydrodynamic regime, the viscosity tensor of such fluids has a nonvanishing odd component. In this scenario, fluctuating viscous stresses drive the propagation of plasmons, whose dispersion relations are modified by nondissipative odd viscous waves. Coulomb coupling of electron density fluctuations induces a drag force exerted by one layer on the other in the presence of a steady flow. This drag force can be expressed through the dynamic structure factor of the electron liquid, which is peaked at frequencies corresponding to plasmon resonances in the bilayer. As a result, the drag resistivity depends on the dissipationless odd viscosity of the fluid. We quantify this effect and present a general theory of hydrodynamic fluctuations applicable to odd electron liquids, both with and without Galilean invariance.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 3 figures
A Novel Graphyne-Like Carbon Allotrope: 2D Dewar-Anthracyne
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-11 20:00 EDT
José A. S. Laranjeira, Kleuton A. L. Lima, Nicolas F. Martins, Luiz A. Ribeiro Junior, Douglas S. Galvao, Julio R. Sambrano
Anthracyne (2DDA). 2DDA consists of chains of Dewar-anthracenes connected by acetylenic linkages. DFT-based simulations show that 2DDA is thermally stable and exhibits no imaginary phonon modes, confirming its dynamic stability. 2DDA is metallic with Dirac-like features near the Fermi level, dominated by C pz orbitals. It shows marked mechanical anisotropy, with Young’s modulus of 176.24 N/m (x) and 31.51 N/m (y), shear modulus up to 69.14 N/m, and Poisson’s ratio varying from 0.27 to 0.87. The material also exhibits strong anisotropic optical absorption in the visible and ultraviolet ranges. Raman and IR spectra reveal intense bands at 648 cm-1 (Raman) and 1292 cm-1 (Infrared). Nanoribbon structures derived from 2DDA exhibit diverse electronic behaviors, from metals up to bandgap values of up to 0.42 eV, depending on the edge-type terminations and width. These findings demonstrate the 2DDA potential for nanoelectronic and optoelectronic applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages
Localization and Topology in Noncentrosymmetric Superconductors with Disorder
New Submission | Other Condensed Matter (cond-mat.other) | 2025-04-11 20:00 EDT
Jinkun Wang, Sigma-Jun Lu, Mei Xiang, Wu-Ming Liu
The celebrated Kitaev chain reveals a captivating phase diagram in the presence of various disorders, encompassing multifractal states and topological Anderson phases. In this work, we investigate the localization and topological properties of a dimerized topological noncentrosymmetric superconductor (NCS) under quasiperiodic and Anderson disorders. Using both global and local characterization methods, we identify energy-dependent transitions from ergodic to multifractal and localized states. Extended multifractal regimes emerge from the competition between dimerization, NCS order, and quasiperiodic modulation. This interplay causes localization to occur preferentially in different energy bands depending on the disorder strength, with the lowest bands exhibiting the highest sensitivity to parameter variations. We employ the real-space polarization method to compute the $ \mathbb{Z}_2$ topological invariant, revealing alternating topological and trivial phases as the quasiperiodic potential increases, a behavior distinct from the typical topological Anderson phase diagram. Additionally, the topological states show remarkable robustness against Anderson disorder, providing new insights into topological phase stability in non-centrosymmetric systems. Finally, we propose a feasible experimental scheme based on superconducting Josephson junctions, where NCS-like behavior can be engineered via spatially modulated supercurrents. Our findings highlight the distinct roles of different disorder types in shaping localization and topology, providing insight into the engineering of Majorana zero modes and offering profound implications for topological quantum encryption schemes.
Other Condensed Matter (cond-mat.other)
Fractional Chern Insulator and Quantum Anomalous Hall Crystal in Twisted MoTe$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-11 20:00 EDT
Jialin Chen, Qiaoyi Li, Xiaoyu Wang, Wei Li
Recent experimental advances have uncovered fractional Chern insulators in twisted MoTe$ _2$ (tMoTe$ _2$ ) systems, posing significant theoretical challenges in understanding the interaction effects and correlated topological phases. Here, we construct a realistic moiré lattice model tailored for tMoTe$ _2$ and conduct investigations using state-of-the-art tensor-network methods. Our ground-state calculations reveal a rich array of interaction- and filling-dependent phases, including the FCI, Chern insulator, and generalized Wigner crystal, etc., explaining recent experimental observations. Moreover, we reveal quantum anomalous Hall crystals exhibiting integer Hall conductivity at fractional moiré unit cell fillings, which opens new avenues for experimental exploration in tMoTe$ _2$ . In the FCI phase, dynamical simulations reveal a single-particle continuum with a finite charge gap, indicating the presence of fractional charge excitations. Moreover, our finite-temperature calculations determine the characteristic temperatures for charge activation and ferromagnetic (FM) transitions, consistent with experiments. We find that the charge gap is significantly larger than the energy scales of both thermal activation and FM transitions, explaining recent experimental observations. Overall, by integrating ground-state, finite-temperature, and dynamical tensor-network calculations on the real-space model, we establish a theoretical framework for understanding and exploring correlated topological phases in tMoTe$ _2$ and related systems.
Strongly Correlated Electrons (cond-mat.str-el)
12+11 pages, 6+10 figures
Stacking-induced ferroelectricity in tetralayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-11 20:00 EDT
Amit Singh, Shuigang Xu, Patrick Johansen Sarsfield, Pablo Diaz Nunez, Ziwei Wang, Sergey Slizovskiy, Nicholas Kay, Jun Yin, Yashar Mayamei, Takashi Taniguchi, Kenji Watanabe, Qian Yang, Kostya S. Novoselov, Vladimir I. Falko, Artem Mishchenko
Recent studies have reported emergent ferroelectric behavior in twisted or moiré-engineered graphene-based van der Waals heterostructures, yet the microscopic origin of this effect remains under debate. Pristine mono- or few-layer graphene lacks a permanent dipole due to its centrosymmetric lattice, making the emergence of ferroelectricity unlikely. However, mixed-stacked graphene, such as the ABCB tetralayer configuration, breaks both inversion and mirror symmetry and has been theoretically predicted to support electrically switchable dipoles. ABCB graphene represents the simplest natural graphene polytype exhibiting intrinsic out-of-plane polarization, arising from asymmetric charge carrier distribution across its layers. Here, we report robust ferroelectric behavior in dual-gated, non-aligned ABCB tetralayer graphene encapsulated in hexagonal boron nitride. The device exhibits pronounced hysteresis in resistance under both top and bottom gate modulation, with the effect persisting up to room temperature. This hysteresis originates from reversible layer-polarized charge reordering, driven by gate-induced transitions between ABCB and BCBA stacking configurations – without requiring moiré superlattices. Our findings establish stacking-order-induced symmetry breaking as a fundamental route to electronic ferroelectricity in graphene and open pathways for non-volatile memory applications based on naturally occurring mixed-stacked multilayer graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)