CMP Journal 2025-10-13
Statistics
Nature: 1
Nature Materials: 2
arXiv: 57
Nature
Host cell Z-RNAs activate ZBP1 during virus infections
Original Paper | Pattern recognition receptors | 2025-10-12 20:00 EDT
Chaoran Yin, Aleksandr Fedorov, Hongyan Guo, Jeremy Chase Crawford, Claire Rousseau, Xiao Zhong, Riley M. Williams, Avishekh Gautam, Heather S. Koehler, Adam W. Whisnant, Thomas Hennig, Anna Rozina, Yuhan Zhong, Shuangjuan Lv, Valter Bergant, Shuqi Wang, Peter Dröge, Sven Miller, Maria Poptsova, Jan Rehwinkel, Andreas Pichlmair, Edward S. Mocarski, Paul G. Thomas, Lars Dölken, Ting Zhang, Alan Herbert, Siddharth Balachandran
Herpes simplex virus 1 (HSV-1) and Influenza A viruses (IAV) induce Z-form nucleic acid Binding Protein 1 (ZBP1)-initiated cell death1-8. ZBP1 is activated by Z-RNA1,7,9, and the Z-RNAs which trigger ZBP1 during HSV-1 and IAV infections were assumed to be of viral origin1. However, we show here that host cell-encoded Z-RNAs are major and sufficient ZBP1 activating ligands following infection by these two human pathogens. The majority of cellular Z-RNAs mapped to intergenic endogenous retroelements (EREs) embedded within abnormally long 3’ extensions of host cell mRNAs. These aberrant host cell transcripts arose as a consequence of Disruption of Transcription Termination (DoTT), a virus-driven phenomenon which disables Cleavage and Polyadenylation Specificity Factor (CPSF)-mediated 3’ processing of nascent pre-mRNAs10-15. Mutant viruses lacking ICP27 or NS1, the virus-encoded proteins responsible for inhibiting CPSF and triggering DoTT13,15, failed to induce host cell Z-RNA accrual and were attenuated in their ability to stimulate ZBP1. Ectopic expression of HSV-1 ICP27 or IAV NS1, or pharmacological blockade of CPSF activity, induced accumulation of host cell Z-RNAs and activated ZBP1. These results demonstrate that DoTT-generated cellular Z-RNAs are bona fide ZBP1 ligands, and position ZBP1-activated cell death as a host response to counter viral disruption of the cellular transcriptional machinery.
Pattern recognition receptors, Viral infection
Nature Materials
Ultrafast surface melting of orbital order in La0.5Sr1.5MnO4
Original Paper | Nanoscale materials | 2025-10-12 20:00 EDT
Maurizio Monti, Khalid M. Siddiqui, Daniel Perez-Salinas, Naman Agarwal, Martin Bremholm, Xiang Li, Dharmalingam Prabhakaran, Xin Liu, Danylo Babich, Mathias Sander, Yunpei Deng, Henrik T. Lemke, Roman Mankowsky, Xuerong Liu, Simon E. Wall
Understanding how light modifies long-range order in quantum materials is key to improving our ability to control functionality. However, this is challenging if the response is heterogeneous. Here we address the most common form of light-induced heterogeneity–surface melting–and measure the dynamics of orbital order in the layered manganite La0.5Sr1.5MnO4. We isolate the surface dynamics from the bulk by measuring the orbital truncation rod and orbital Bragg peak. After photoexcitation, the orbital Bragg peak shows an unusual narrowing, which suggests an increase in correlation length of the probed volume. By contrast, the correlation length at the surface decreases. These differences can be reconciled if the material is heterogeneous, and light melts a less ordered surface. By isolating the surface response, we determine that the loss of long-range order is an incoherent process, which is probably accompanied by the formation of local polarons.
Nanoscale materials, Phase transitions and critical phenomena, Structure of solids and liquids
Near-100% spontaneous rolling up of polar van der Waals materials
Original Paper | Nanoscale materials | 2025-10-12 20:00 EDT
Zhi Zhang, Yuwei Zhang, Kangjun Lu, Jun-Jie Zhang, Nannan Zhang, Rui Feng, Haoran Ye, Xiaoli Zhou, Linglong Li, Dongyang Wan, Junpeng Lu, Zhenhua Ni, Jinlan Wang, Qian Chen, Jiong Lu, Zejun Li
Rolling two-dimensional materials into one-dimensional nanoscrolls introduces curvature, chirality and symmetry breaking, enabling emergent properties. Conventional methods relying on external driving forces, however, exhibit poor control, low yield and limited reproducibility. Here we report spontaneous scrolling in polar van der Waals materials via an electrochemical intercalation/exfoliation process, enabling scalable nanoscroll production. This self-rolling is driven intrinsically by out-of-plane electric polarization (P⊥), where the magnitude of P⊥ is modulated by the intercalant size. Validated across eight polar materials, this approach achieves virtually 100% yield and reproducibility with defined scrolling direction, surpassing external driving force limitations. The nanoscrolls exhibit layer-independent inversion symmetry breaking and coherently enhanced second-harmonic generation, exceeding two-dimensional flakes by ~100-fold and rivalling leading two-dimensional nonlinear materials. Electrochemical initiation further facilitates metal-ion co-intercalation, yielding ten hybrid nanoscroll architectures. These findings establish a scalable route to create one-dimensional nanostructures and hybrid heterostructures, paving the way for designer quantum solids and van der Waals superlattices in quantum nanodevices.
Nanoscale materials, Nanoscience and technology, Two-dimensional materials
arXiv
Coherent Optical Control of Electron Dynamics in Patterned Graphene Nanoribbons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Riek H. Rüstemeier, H. P. Ojeda Collado, Ludwig Mathey
The field of coherent electronics aims to advance electronic functionalities by utilizing quantum coherence. Here, we demonstrate a viable and versatile methodology for controlling electron dynamics optically in graphene nanoribbons. In particular, we propose to flatten the band structure of armchair graphene nanoribbons via control electrodes, arranged periodically along the extended direction of the nanoribbon. This addresses a key mechanism for dephasing in solids, which derives from the momentum dependence of the energy gap between the valence and the conduction band. We design an optimal driving field pulse to produce collective Rabi oscillations between these bands, in their flattened configuration. As an example for coherent control, we show that these optimized pulses can be used to invert the entire electronic band population by a $ \pi$ pulse in a reversible fashion, and to create a superposition state via a $ \pi/2$ pulse, which generates an alternating photocurrent. Our proposal consists of a platform and methodological approach to optically control the electron dynamics of graphene nanoribbons, paving the way toward novel coherent electronic and quantum information processing devices in solid-state materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Theory of non-resonant Raman scattering from electrons in nodal and flat bands
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Raman scattering is emerging as a surprising probe of electron topology in quantum materials. It has been used recently to detect and characterize a topological phase transition that accompanies the magnetic transition in Nd$ _2$ Ir$ _2$ O$ _7$ . Here we present a theory of Raman scattering from nodal electrons with Weyl and quadratic band touching spectra, which has to reach beyond the standard effective mass approximation. After reviewing and providing the details of our previous theory development, we discuss several new results. We show that the light-polarization dependence of Raman scattering is universal in the case of Weyl electrons and given by an analytic expression, while it contains symmetry-protected features in the case of quadratic band-touching nodes. We also analyze modifications of the Raman signal due to the ubiquitous tilting of the Weyl spectrum, and argue that universality is lost only in a finite frequency range that springs out of the threshold frequency for untilted nodes. Finally, we explore the frequency dependence of Raman scattering for the case of Dirac electrons coexisting with a flat band in the same region of the first Brillouin zone, which is inspired by the material V$ _{1/3}$ NbS$ _2$ .
Materials Science (cond-mat.mtrl-sci)
18 pages, 7 figures
Extreme events scaling in self-organized critical models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-13 20:00 EDT
Abdul Quadir, Haider Hasan Jafri
We study extreme events of avalanche activities in finite-size two-dimensional self-organized critical (SOC) models, specifically the stochastic Manna model (SMM) and the Bak-Tang-Weisenfeld (BTW) sandpile model. Employing the approach of block maxima, the study numerically reveals that the distributions for extreme avalanche size and area follow the generalized extreme value (GEV) distribution. The extreme avalanche size follows the Gumbel distribution with shape parameter $ \xi=0$ while in the case of the extreme avalanche area, we report $ \xi>0$ . We propose scaling functions for extreme avalanche activities that connect the activities on different length scales. With the help of data collapse, we estimate the precise values of these critical exponents. The scaling functions provide an understanding of the intricate dynamics for different variants of the sandpile model, shedding light on the relationship between system size and extreme event characteristics. Our findings give insight into the extreme behavior of SOC models and offer a framework to understand the statistical properties of extreme events.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:2410.05705
Accelerated prediction of dielectric functions in solar cell materials with graph neural networks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Caden Ginter, Kamal Choudhary, Subhasish Mandal
We present an atomistic line graph neural network (ALIGNN) model for predicting dielectric functions directly from crystal structures. Trained on $ \sim$ 7000 dielectric functions from the JARVIS-DFT database computed with a meta-GGA exchange-correlation functional, the model accurately reproduces spectral features, including peak intensities and overall line shapes, while enabling efficient high-throughput screening. Applied to the recently developed Alexandria materials database, containing over four hundred thousand insulating materials, we uncover a clear elemental trend, with vanadium emerging as a strong indicator of materials with high-spectroscopic limited maximum efficiency (SLME). In particular, vanadium-based perovskite materials show a substantially higher fraction of high-SLME compounds compared to the database average, underscoring their promise for optoelectronic applications.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Light-induced pseudo-magnetic fields in three-dimensional topological semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Arpit Raj, Swati Chaudhary, Martin Rodriguez-Vega, Maia G. Vergniory, Roni Ilan, Gregory A. Fiete
In this work, we show that suitably designed spatially varying linearly polarized light provides a versatile route to generate and control pseudo-magnetic fields in Weyl semimetals through Floquet engineering. Within a high-frequency expansion, we derive an effective axial gauge potential $ \mathbf{A}_5(\mathbf{r})$ whose curl gives the pseudo-magnetic field $ \mathbf{B}_5(\mathbf{r})$ . By mapping the light profile to $ \mathbf{A}_5(\mathbf{r})$ , we establish design principles for pseudo-magnetic field textures that mimic strain-induced gauge fields while offering key advantages like dynamic control, full reversibility, spatial selectivity, and absence of material deformation. We compare the Landau-level spectra produced by uniform real and pseudo-magnetic fields and also analyze both their linear optical conductivity and the second-order dc responses. Our results enable real-time manipulation of pseudo-magnetic fields and predict clear experimental signatures for optically engineered gauge fields in topological semimetals.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 13 figures
Crystal-Field–Driven Magnetoelectricity in the Triangular Quantum Magnet CeMgAl${11}$O${19}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-13 20:00 EDT
Sonu Kumar (1,2), Gaël Bastien (1), Maxim Savinov (3), Petr Proschek (1), Adam Eliáš (1), Karol Załęski (4), Małgorzata Śliwińska-Bartkowiak (2), Ross H. Colman (1), Stanislav Kamba (3) ((1) Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Prague, Czech Republic, (2) Adam Mickiewicz University, Faculty of Physics and Astronomy, Department of Experimental Physics of Condensed Phase, Poznań, Poland, (3) Institute of Physics, Czech Academy of Sciences, Prague, Czech Republic, (4) Adam Mickiewicz University, NanoBioMedical Centre, Poznań, Poland)
We report dielectric and magnetoelectric studies of single-crystalline \ce{CeMgAl11O19}, a Kramers triangular magnet embedded in a polarizable hexaaluminate lattice. In zero magnetic field, the permittivity $ \varepsilon’(T)$ follows the Barrett law of a quantum paraelectric down to 25 K, below which a broad minimum develops near 3 K without evidence of static ferroelectric or magnetic order. Application of magnetic fields up to \SI{9}{\tesla} shifts this minimum to higher temperatures and broadens it, evidencing a tunable magnetoelectric this http URL magnetoelectric coupling was characterized using results from magnetization measurements. The anomaly temperature $ T^\ast$ , extracted from the local minimum of $ \varepsilon’(T)$ , exhibits a linear dependence on the squared magnetization $ M^2$ , consistent with the biquadratic magnetoelectric coupling allowed in centrosymmetric systems. This magnetoelectric effect, mediated by spin-orbit-entangled Kramers doublets interacting with a frustrated antipolar liquid, establishes \ce{CeMgAl11O19} as a prototype for exploring quantum magnetoelectricity in frustrated systems.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Work Function Mapping Across a-In2Se3 to α-In2Se3 to γ-InSe in RF-Sputtered Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Marius O. Eji, Md. Sakauat Hasan Sakib, Joseph P. Corbett
Indium selenide is a phase-change chalcogenide whose polymorphism enables a variety of physical properties to be tuned. Here we directly quantify the evolution of the surface work function across the amorphous-to-crystalline transition in RF-sputtered In2Se3 thin films grown on c-plane Al2O3 (001). By varying deposition temperature (100-500 °C) and film thickness, we establish processing windows for a- In2Se3, {\alpha}-In2Se3, and {\gamma}-InSe, and correlate structure with electronic and morphological properties. X-ray diffraction shows films deposited at 100 to 200 °C are amorphous, 300 to 400 °C yields {\alpha}-In2Se3, whereas 500 °C yields {\gamma}-InSe. Kelvin probe force microscopy (KPFM) maps the surface potential and yields spatially averaged work functions spanning 5.26 to 6.64 eV across the amorphous-crystalline transformation; pronounced intra-film heterogeneity is observed, with select {\alpha}-phase and {\gamma}-InSe grains exhibiting work functions exceeding the local mean. Topographical distinctions are found between phases with hexagonally faceted grains in the crystalline state, whereas homogeneous nano-mounds are found in amorphous films. Analysis of Tauc plots revealed optical bandgaps in the range of 2.50 to 1.55 eV across the observed phases. X-ray fluorescence (XRF) measurements further indicated that the indium to selenium concentration ratio varied between 0.70 {\pm} 0.1 to 1.01 {\pm} 0.1 as the deposition temperature increased from 100 to 500 °C. These measurements provide direct, spatially resolved quantification of work-function evolution through the phase change, supplying parameters essential for contact engineering and device integration of In2Se3 and InSe.
Materials Science (cond-mat.mtrl-sci)
Modeling changes in atomic structure around a vacancy with increasing temperature and calculation of temperature dependences of vacancy characteristics in bcc iron
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
M. Boboqambarova (1), A.V. Nazarov (1,2) ((1) National Research Nuclear University MEPhI, Moscow, Russia (1), (2) National Research Center “Kurchatov Institute”)
We developed an original natural thermostat algorithm to simulate the direct change in interatomic distances with temperature in both an ideal crystal and a system with a vacancy. In contrast to previous work, the results indicate that in a system with a defect, the radii of the first ten coordination spheres change nearly linearly with increasing temperature. However, the coefficients determining these dependencies, unlike the interatomic distances farther from the vacancy, are not equal to the linear thermal expansion coefficient of the ideal crystal. The implications of these results are discussed.
Materials Science (cond-mat.mtrl-sci)
7 pages, 6 figures
Simulating dynamic bonding in soft materials
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-13 20:00 EDT
Tyla R. Holoman, B. P. Prajwal, Glen M. Hocky, Thomas M. Truskett
Dynamic bonding is an essential feature of many soft materials. Molecular simulations have proven to be a powerful tool for modeling bonding kinetics and thermodynamics in these materials, providing insights into their properties that cannot be obtained by experiments alone. Here, we review recent advances in modeling dynamic bonding in soft matter via molecular dynamics, Monte Carlo, and hybrid simulation methods, highlighting outstanding challenges and future directions.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph), Computational Physics (physics.comp-ph)
26 pages, 3 figures, 1 table
Patchy Particles Design: From Floppy Modes to Sloppy Dimensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-13 20:00 EDT
Gregory Snyder, Chrisy Xiyu Du
Patchy particles have proven to be a prominent model for studying the self-assembly behavior of various systems, ranging from finite clusters to bulk crystal assemblies, and from synthetic colloidal particles to viruses. The patchy particle model is flexible, but it also comes with its own pitfalls – the potential design space is infinite. Many efforts have been put into building inverse-design frameworks that efficiently design patchy particles for targeted assembly behaviors. In contrast, little work has been done on investigating the interplay between different types of parameters that can be optimized for patchy particles, such as patch location, patch size, and patch binding energies. Here, by utilizing molecular dynamics with automatic differentiation, we elucidate the relationships between different potential optimization parameters and provide general guidelines on how to approach patchy particle design for various types of finite clusters. Specifically, we find that the design parameter landscape is highly dependent on the floppiness of the target structure, and we can identify stiff and sloppy parameters by computing the Hessians of all optimization parameters.
Soft Condensed Matter (cond-mat.soft)
Hidden integer quantum ferroelectricity in chiral Tellurium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Wei Luo, Sihan Deng, Muting Xie, Junyi Ji, Hongjun Xiang, Laurent Bellaiche
Ferroelectricity is a cornerstone of functional materials research, enabling diverse technologies from non-volatile memory to optoelectronics. Recently, type-I integer quantum ferroelectricity (IQFE), unconstrained by symmetry, has been proposed and experimentally demonstrated; however, as it arises from ionic displacements of an integer lattice vector, the initial and final states are macroscopically indistinguishable, rendering the physical properties unchanged. Here, we propose for the first time the nontrivial counterpart (i.e., type-II IQFE) where the polarization difference between the initial and final states is quantized but the macroscopical properties differ. We further demonstrate the existence of type-II IQFE in bulk chiral tellurium. In few-layer tellurium, the total polarization remains nearly quantized, composed of a bulk-inherited quantum component and a small surface-induced contribution. Molecular dynamics simulations reveal surface-initiated, layer-by-layer switching driven by reduced energy barriers, explaining why ferroelectricity was observed experimentally in few-layer tellurium, but not in bulk tellurium yet. Interestingly, the chirality of the initial and final states in bulk tellurium is opposite, suggesting a novel way to control structural chirality with electric field in chiral photonics and nonvolatile ferroelectric memory devices.
Materials Science (cond-mat.mtrl-sci)
16 pages, 4 figures
High-Throughput Screening of Transition Metal-Based 2D Multilayer Kagome Materials via the “1 + 3” Design Strategy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Xing-Yu Wang, En-Qi Bao, Su-Yang Shen, Jun-Hui Yuan, Jiafu Wang
Two-dimensional (2D) kagome materials have drawn extensive research interest due to their unique electronic properties, like flat bands, magnetic frustration, and topological quantum states, which enable precise quantum state control and novel device innovation. Yet, simultaneously achieving high stability, tunability, and multifunctionality in 2D kagome systems remains a key material design challenge. In this study, we innovatively propose a new paradigm for constructing two-dimensional multi-kagome-layer materials based on the “1+3” design concept. By seamlessly integrating high-throughput screening techniques, we have successfully identified 6,379 novel 2D multilayer kagome candidates from a vast pool of candidates. These materials exhibit a rich diversity of types, encompassing 173 metals, 27 semimetals, 166 ferromagnetic semiconductors, and as many as 6,013 semiconductors. Furthermore, based on the 2D flat-band scoring criteria, we conducted a detailed analysis of the flat-band characteristics of the energy bands near the Fermi level in the predicted systems. Our findings reveal that approximately two-thirds of the systems meet the 2D flat-band scoring criteria, and notably, several systems exhibit nearly perfect flat-band characteristics. Our work provides an excellent paradigm for the design and research of 2D multilayer kagome materials
Materials Science (cond-mat.mtrl-sci)
20 pages, 5 figures
Gravity-Induced Modulation of Negative Differential Thermal Resistance in Fluids
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-13 20:00 EDT
Qiyuan Zhang, Juncheng Guo, Juchang Zou, Rongxiang Luo
We investigate how gravity influences negative differential thermal resistance (NDTR) in fluids modeled by multiparticle collision dynamics. In the integrable case, we derive the heat flux formula for the system exhibiting the NDTR effect, and show that by introducing a gravity along the direction of the thermodynamic force, the temperature difference required for the occurrence of NDTR can be greatly reduced. Meanwhile, we also demonstrate that the heat-bath-induced NDTR mechanism – originally found to be applicable only to weakly interacting systems – can now operate in systems with stronger interactions due to the presence of gravity, and further remains robust even in mixed fluids. These results provide new insights into heat transport and establish a theoretical foundation for designing fluidic thermal devices that harness the NDTR effect under gravity.
Statistical Mechanics (cond-mat.stat-mech)
Collective Variables Based on Multipole Expansion of Ewald Summation for Crystallization
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-13 20:00 EDT
YaoKun Lei, MaoDong Li, Yi Isaac Yang
Crystallization, a fundamental phase transition process governing material formation in natural and industrial contexts, involves the spontaneous emergence of long-range structural order from disordered phases. This long-range periodicity involves spatial and molecular orientation order. Molecular dynamics (MD) simulations of crystallization require collective variables (CVs) that accurately distinguish this long-\range periodicity. Existing CVs based on local descriptors (e.g., bond-orientational order) often lack transferability across crystal structures. To address this, we propose a unified CV framework derived from the multipole expansion of Ewald summation: a mathematical formalism bridging X-ray diffraction (XRD) principles and electrostatic energy computation in MD. By projecting atomic configurations onto a basis of spherical harmonics (complete for angular function representation), our CV achieves high-fidelity encoding of both translational and orientational order. Metadynamics simulations demonstrate that this CV drives efficient sampling of polymorphic pathways for known crystals and predicts stable phases even without crystal structures. This approach shows potential as a transferable platform for ab initio crystal structure prediction.
Statistical Mechanics (cond-mat.stat-mech), Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
X-ray imaging of antiferromagnetic octupole domains in Mn$_3$Sn
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Max T. Birch, Sebastian Wintz, Yuhan Sun, Akiko Kikkawa, Markus Weigand, Takahisa Arima, Yoshinori Tokura
Novel antiferromagnets with broken time reversal symmetry (TRS) have launched a new direction in spintronics research, combining the advantageous dynamical properties of conventional antiferromagnets with the controllability typically associated with ferromagnets. However, antiferromagnetic domains are notoriously challenging to image in real-space. X-ray magnetic circular dichroism (XMCD) offers a route to overcome this difficulty: XMCD contrast may be finite in TRS-breaking antiferromagnets with an appropriate magnetic space group. Here, we exploit this to image the octupole domains in a focused ion beam-fabricated device of the non-collinear antiferromagnet Mn$ _3$ Sn. Using scanning transmission x-ray microscopy, we spatially resolve the weak pre-edge XMCD contrast (of 0.2%) that is sensitive to $ T_z$ , achieving a contrast resolution better than 0.02%. We observe hysteretic switching of the octupole order through both the XMCD contrast and the corresponding anomalous Hall effect within the same device. These results confirm the bulk nature of this contrast, and establish XMCD-based microscopy as a powerful real space imaging method for TRS-breaking antiferromagnets, including altermagnets, enabling future studies of their dynamics, switching, and symmetry-tunable phenomena.
Materials Science (cond-mat.mtrl-sci)
Atomistic origin of low thermal conductivity in quaternary chalcogenides Cu(Cd, Zn)$_2$InTe$_4$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Nirmalya Jana, Amit Agarwal, Koushik Pal
Crystalline semiconductors with intrinsically low lattice thermal conductivity ($ \mathcal{K}$ ) are vital for device applications such as barrier coatings and thermoelectrics. Quaternary chalcogenide semiconductors such as CuCd$ _2$ InTe$ _4$ and CuZn$ _2$ InTe$ _4$ are experimentally shown to exhibit low $ \mathcal{K}$ , yet its microscopic origin remains poorly understood. Here, we analyse their thermal transport mechanisms using a unified first-principles framework that captures both the Peierls (particle-like propagation, $ \mathcal{K}_P$ ) and coherence (wave-like tunneling, $ \mathcal{K}_C$ ) mechanisms of phonon transport. We show that extended antibonding states below the Fermi level lead to enhanced phonon anharmonicity and strong scattering of heat-carrying phonon modes, suppressing $ \mathcal{K}$ in these chalcogenides. We show that $ \mathcal{K}_P$ dominates the total thermal conductivity, while $ \mathcal{K}_C$ remains negligible even under strong anharmonicity of the phonon modes. The heavier Cd ions in CuCd$ _2$ InTe$ _4$ induce greater acoustic-optical phonon overlap and scattering compared to CuZn$ _2$ InTe$ _4$ , further lowering thermal conductivity of the former. Additionally, grain boundary scattering in realistic samples contributes to further suppression of thermal transport. Our findings establish the atomistic origins of low $ \mathcal{K}$ in quaternary chalcogenides and offer guiding principles for designing low-thermal-conductivity semiconductors.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
Imaging of Gate-Controlled Suppression of Superconductivity via the Meissner Effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
P. J. Scheidegger, K. J. Knapp, U. Ognjanovic, L. Ruf, S. Diesch, E. Scheer, A. Di Bernardo, C. L. Degen
It was recently discovered that supercurrents flowing through thin superconducting nanowires can be quenched by a gate voltage. This gate control of supercurrents, known as the GCS effect, could enable superconducting transistor logic. Here, we report that the GCS also manifests in a suppression of Meissner screening, establishing the phenomenon as a genuine feature of superconductivity that is not restricted to transport. Using a scanning nitrogen-vacancy magnetometer at sub-Kelvin temperatures, we image the nanoscale spatial region of GCS suppression in micron-size niobium islands. Our observations are compatible with a microscopic hot-spot model of quasiparticle generation and diffusion, and in conflict with other candidate mechanisms such as Joule heating or an electric field effect. Our work introduces an alternative means for studying quasiparticle dynamics in superconducting nanostructures, and showcases the power of local imaging techniques for understanding emergent condensed matter phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
9 pages, 4 figures; supplementary information available on request
Active Rosensweig Patterns
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-13 20:00 EDT
Carlo Rigoni, Max Philipp Holl, Alberto Scacchi, Emil Stråka, Fereshteh Sohrabi, Mikko P. Haataja, Maria Sammalkorpi, Jaakko V.I. Timonen
Ferrofluids, colloidal dispersions of magnetic nanoparticles, are renowned for pattern formation like few other materials. The Rosensweig instability of a horizontal ferrofluid-air interface in perpendicular magnetic field is especially well known classically, this instability sets the air-ferrofluid interface into an array of spikes that correspond to a new free energy minimum of the system. However, once the pattern is formed, it does not exhibit any notable thermal or non-equilibrium fluctuations, i.e., it is passive. In this work, we present an active version of the Rosensweig patterns. We realize them experimentally by driving a dispersion of magnetic nanoparticles with an electric field into a non-equilibrium gradient state and by inducing the instability using a magnetic field. The coupling of electric and magnetic forcing leads to patterns that can be adjusted from quiescent classic Rosensweig-like behavior (at low activity) to highly dynamic ones displaying peak and defect dynamics, as well as tunability of structure periodicities beyond what is possible in the classic systems (at high activity). We analyze the results using an active agent-based approach as well as a continuum perspective. We construct a simple equilibrium-like effective Rosensweig model to describe the onset of the patterns and propose a minimal Swift-Hohenberg type model capturing the essential active pattern dynamics. Our results suggest that classic continuum systems exhibiting pattern formation can be activated to display life-inspired non-equilibrium phenomena.
Soft Condensed Matter (cond-mat.soft)
Parametric Drive of a Double Quantum Dot in a Cavity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
L. Jarjat, B. Hue, T. Philippe-Kagan, B. Neukelmance, J. Craquelin, A. Théry, C. Fruy, G. Abulizi, J. Becdelievre, M.M. Desjardins, T. Kontos, M.R. Delbecq
We demonstrate the parametric modulation of a double quantum dot charge dipole coupled to a cavity, at the cavity frequency, achieving an amplified readout signal compared to conventional dispersive protocols. Our findings show that the observed cavity field displacement originates from dipole radiation within the cavity, rather than from a longitudinal coupling mechanism, yet exhibits the same signatures while relying on a transverse coupling. By carefully tuning the phase and amplitude of the intra-cavity field, we achieve a $ \pi$ -phase shift between two dipole states, resulting in a substantial enhancement of the signal-to-noise ratio. In addition to its applications in quantum dot based qubits in cQED architectures, this protocol could serve as a new promising tool for probing exotic electronic states in mesoscopic circuits embedded in cavities.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
main text 6 pages, 4 figures; supplementary material 11 pages, 11 figures
Phys. Rev. Lett. 135, 153603 (2025)
Chern insulators and topological flat bands in cavity-embedded kagome systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Hikaru Goto, Ryo Okugawa, Takami Tohyama
We investigate topological band structures of a kagome system coupled to a circularly polarized cavity mode, using a model based on a muffin-tin potential and quantum light-matter interaction. We show that Chern insulating phases emerge in the cavity-embedded kagome system due to the light-matter interaction that breaks time-reversal symmetry. We also find that a nearly flat band can be topologically nontrivial with a nonzero Chern number. By varying the light-matter interaction, we also reveal that topological phase transitions occur between different Chern insulating phases in the ultrastrong coupling regime. The phase transitions change the sign of the Chern number, switching the direction of the edge current. We demonstrate the existence of topological edge modes in the cavity-embedded kagome Chern insulators by constructing a low-energy effective tight-binding model.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics), Quantum Physics (quant-ph)
9 pages, 6 figures
Nematic Fluctuations and Electronic Correlations in Heavily Hole-Doped Ba$_{1-x}$K$_x$Fe$_2$As$_2$ Probed by Elastoresistance
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-13 20:00 EDT
Franz Eckelt, Steffen Sykora, Xiaochen Hong, Vilmos Koscis, Vadim Grinenko, Bernd Büchner, Kunihiro Kihou, Chu-Ho Lee, Christian Hess
This work investigates nematic fluctuations and electronic correlations in the hole-doped iron pnictide superconductor Ba$ {1-x}$ K$ x$ Fe$ 2$ As$ 2$ by means of longitudinal and transverse elastoresistance measurements over a wide doping range ($ 0.63 < x < 0.98$ ). For this purpose, the orbital character of the electronic response was revealed by decomposition of the elastoresistance into the $ A_{1g}$ and $ B_{2g}$ symmetry channels. It was shown that at lower doping levels nematic fluctuations in the $ B_{2g}$ channel dominate, while for $ x > 0.68$ the $ A{1g}$ channel becomes dominant and reaches a pronounced maximum at $ x \approx 0.8$ which indicates strong orbital-selective electronic correlations. Despite the dominance of the $ A{1g}$ signal at high doping, a weak contribution in the $ B{2g}$ channel persists, which can be interpreted as a remnant of nematic fluctuations. Model calculations based on a five-orbital tight-binding Hamiltonian with interactions attribute the observed enhancement in the $ A{1g}$ channel to an orbital-selective Kondo-like resonance, predominantly involving the $ d_{xy}$ orbital. We discuss our results in relation to the evolution of the Sommerfeld coefficient reported in the literature and a reported change of the superconducting order parameter. All this indicates that for $ x > 0.68$ qualitatively new physics emerges. Our findings suggest that electronic correlations in the strongly hole-doped regime play an important role in superconductivity, while the detectable weak nematic fluctuations may also be of relevance.
Strongly Correlated Electrons (cond-mat.str-el)
Altermagnetism and Superconductivity: A Short Historical Review
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-13 20:00 EDT
This article explores the deep interconnections among three seemingly unrelated concepts in condensed matter physics: electronic liquid crystal phases, multipole expansions, and altermagnetism. At the heart of these phenomena lies a shared foundation: spin-momentum locking in the nonrelativistic regime. Originally proposed in the context of electronic liquid crystal phases, spin-momentum locking was later elegantly incorporated into the formalism of multipole expansions. This framework can be further extended across multiple atomic sites, making it particularly effective for describing altermagnets, which feature localized magnetic moments distributed over at least two sublattices. In the second part of the article, we examine superconducting phenomena that stem from this shared mechanism, focusing on superconductivity in systems with spin-momentum locked Fermi surfaces. We highlight a rich variety of unconventional superconducting states, including finite-momentum pairing, $ d$ -wave and spin-triplet superconductivity, and topological Bogoliubov Fermi surfaces, among others. Additional related topics are addressed in the concluding section. Overall, this work offers both an accessible introduction to the newly identified magnetic order known as altermagnetism and a conceptual guide for researchers aiming to harness the ensuing unconventional superconductivity in the development of future quantum technologies.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
8 figures
An exactly solvable asymmetric simple inclusion process
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-13 20:00 EDT
We study a generalization of the asymmetric simple inclusion process (ASIP) on a periodic one-dimensional lattice, where the integers in the particles rates are deformed to their $ t$ -analogues. We call this the $ (q, t, \theta)$ ~ASIP, where $ q$ is the asymmetric hopping parameter and $ \theta$ is the diffusion parameter. We show that this process is a misanthrope process, and consequently the steady state is independent of $ q$ . We compute the steady state, the one-point correlation and the current in the steady state. In particular, we show that the single-site occupation probabilities follow a \emph{beta-binomial} distribution at $ t=1$ . We compute the two-dimensional phase diagram in various regimes of the parameters $ (t, \theta)$ and perform simulations to justify the results. We also show that a modified form of the steady state weights at $ t \neq 1$ satisfy curious palindromic and antipalindromic symmetries. Lastly, we define an enriched process at $ t=1$ and $ \theta$ an integer which projects onto the $ (q, 1, \theta)$ ~ASIP and whose steady state is uniform, which may be of independent interest.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Combinatorics (math.CO), Probability (math.PR)
31 pages, 12 figures
Quasiparticle effects and strong excitonic features in exfoliable 1D semiconducting materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Simone Grillo, Chiara Cignarella, Friedhelm Bechstedt, Paola Gori, Maurizia Palummo, Davide Campi, Nicola Marzari, Olivia Pulci
We report a comprehensive first-principles study of the electronic and optical properties of recently identified exfoliable one-dimensional semiconducting materials, focusing on chalcogenide-based atomic chains derived from van der Waals-bonded bulk crystals. Specifically, we investigate covalently bonded S3 and Te3 chains, and polar-bonded As2S3 and Bi2Te3 chains, using a fully first-principles approach that combines density-functional theory (DFT), density-functional perturbation theory (DFPT), and many-body perturbation theory within the GW approximation and Bethe-Salpeter equation (BSE). Our vibrational analysis shows that freestanding isolated wires remain dynamically stable, with the zone-center optical phonon modes leading to infrared activity. The main finding of this study is the presence of very strong exciton binding energies (1-3 eV), which make these novel 1D materials ideal platforms for room-temperature excitonic applications. Interestingly, the exciton character remains Wannier-Mott-like, as indicated by average electron-hole separations larger than the lattice constant. Notably, the optical gaps of these materials span a wide range - from infrared (0.8 eV, Bi2Te3), through visible spectrum (yellow: 2.17 eV, Te3; blue: 2.71 eV, As2S3), up to ultraviolet (4.07 eV, S3) - highlighting their versatility for broadband optoelectronic applications. Our results offer a detailed, many-body perspective on the optoelectronic behavior of these low-dimensional materials and underscore their potential for applications in next-generation nanoscale optoelectronic devices.
Materials Science (cond-mat.mtrl-sci)
33 pages, 7 figures, supporting information
$β$-Ga$_2$O$_3$(001) surface reconstructions from first principles and experiment
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Konstantin Lion, Piero Mazzolini, Kingsley Egbo, Toni Markurt, Oliver Bierwagen, Martin Albrecht, Claudia Draxl
We present a comprehensive investigation of reconstructions on $ \beta$ -Ga$ _2$ O$ _3$ (001) combining first-principles calculations with experimental observations. Using {\it ab initio} atomistic thermodynamics and replica-exchange grand-canonical molecular dynamics simulations, we explore the configurational space of possible reconstructions under varying chemical potentials of oxygen and gallium. Our calculations reveal several stable surface reconstructions, most notably a previously unreported 1$ \times$ 2 reconstruction consisting of paired GaO$ _4$ tetrahedra that exhibits remarkable stability across a wide range of experimental growth conditions. In this reconstruction, two Ga atoms share one oxygen bond and are separated by a distance of \SI{2.64}{\angstrom} along the [010] direction. High-angle annular dark-field scanning transmission electron microscopy imaging of homoepitaxially grown (001) layers is consistent with the predicted structure. Additional investigations of possible indium substitution at the surface sites, which can occur during metal-exchange catalysis growth, reveal a cooperative effect in In incorporation, with distinct stability regions for In-substituted structures under O-rich conditions. Our findings provide an understanding for controlling surface properties during epitaxial growth of $ \beta$ -Ga$ _2$ O$ _3$ (001).
Materials Science (cond-mat.mtrl-sci)
Quantum fluctuation-induced first-order breaking of time-reversal symmetry in unconventional superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-13 20:00 EDT
Spontaneous time-reversal symmetry breaking in superconductors with competing non-degenerate pairing channels is an exotic quantum phase transition that could give rise to robust topological superconductivity and unusual magnetism. It is proposed mostly in two-dimensional systems and is signaled by a nonzero relative phase between the two superconducting order parameters, hence it should particularly be prone to order-parameter phase fluctuations. Nevertheless, the existing understanding of it is still at the mean-field level. Here, we illustrate the non-negligible effects of the phase fluctuations on such quantum phase transitions using the hole-doped square-lattice $ t$ -$ J$ model as an example. We derive the phase fluctuation-corrected free energy and show that under the quantum phase fluctuations, the time-reversal asymmetric $ s+id$ phase region splits off a dome featuring a first-order border with the $ d$ phase, indicating the possibility of a phase separation into the time-reversal symmetric and asymmetric phases. The phase fluctuations also narrow the range of the $ s+id$ phase considerably. We further discuss the implications of our findings for recent experiments on disorder-induced first-order quantum breakdown of superconductivity and promising high-temperature topological superconductivity in twisted cuprate Josephson junctions.
Superconductivity (cond-mat.supr-con)
7 pages, 4 figures
Tunable Chern Insulator States with Coexisting Magnonic and Electronic Topology in 2D Honeycomb Kitaev Ferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Haozhou Cai, Zhiming Xu, Jian Wu, Weiyi Pan
The coexistence of topological magnons and electrons in magnetic materials presents a compelling route toward developing low-dissipation, multifunctional spintronic devices. However, material systems enabling their simultaneous realization and control remain largely unexplored. Here, we propose the coexistence and concurrent tunability of magnonic and electronic Chern insulator phases in Kitaev magnets and use MnBr$ _{3}$ monolayer as a prototype. We find the significant Kitaev interaction in MnBr$ _{3}$ induces the magnonic Chern insulator phase, manifesting as the magnon thermal Hall effect. Concurrently, MnBr$ _{3}$ exhibits the quantum anomalous Hall effect driven by its electronic Chern insulator phase. Crucially, we demonstrate that these dual topological phases can be simultaneously controlled by reorienting the in-plane spins with an external magnetic field. Our findings not only deepen the fundamental understanding of spin excitations in Kitaev magnets but also provide a promising platform for exploring the interplay between electronic and magnonic topology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Acoustoelectric Amplification in a Piezoelectric-2DEG Heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Eric Chatterjee, Daniel Soh, Matt Eichenfield
We provide a quantum mechanical description of phonon amplification in a heterostructure consisting of a two-dimensional electron gas (2DEG) stacked on top of a piezoelectric material. An applied drift voltage effectively creates a population inversion in the momentum states of the 2DEG electrons, giving rise to spontaneous emission of phonons. Once an acoustic wave is launched, the pumped electrons release phonons via stimulated emission, returning to depleted ground states before being pumped back to the excited states. We show that whereas efficient amplification using a 1D electron gas requires the acoustic wavelength to roughly equal the average electron-electron spacing, a 2DEG enables efficient amplification for any wavelength greater than the average electron-electron spacing. We derive the imaginary and real parts of the 2DEG first-order acoustic susceptibility as functions of electronic drift velocity in specific limits and derive the gain per unit length for the signal and the quantum noise, with the gain matching the classical result in the short-electronic-lifetime (low-mobility) regime. Moreover, we analyze the gain clamping due to pump depletion and calculate the maximum achievable intensity. Our results provide a framework for designing novel acoustic devices including a quantum phononic laser and phase-insensitive quantum phononic amplifiers.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
29 pages, 8 figures
Strained Donor-Bound Excitons in $^{28}$Si
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
David A. Vogl, Noah L. Braitsch, Başak Ç. Özcan, Niklas S. Vart, M. L. W. Thewalt, Martin S. Brandt
We present a comprehensive experimental study of the neutral donor to donor-bound exciton transition (D$ ^0$ \rightarrow,$ D$ ^0$ X) in isotopically enriched $ ^{28}$ Si, focusing on the group-V donors P, As, and Sb under finely tuned uniaxial stress along the [100] and [110] crystal axes and magnetic fields from 3.5 mT to 1.7 T. From these measurements, donor-specific deformation potentials are extracted. The uniaxial electron deformation potential $ \Xi_\mathrm{u}$ is found to be significantly larger than values reported for other states or transitions in silicon and shows a clear dependence on the donor species, indicating an increased sensitivity of the D$ ^0$ X state to strain and central-cell effects. We also observe a magnetic field dependence of the hole shear deformation potential $ d$ , suggesting a more complex strain coupling mechanism than captured by standard theory. Diamagnetic shift parameters determined from Zeeman spectra show good agreement with earlier measurements. Our results provide a refined parameter set critical for the design of silicon quantum devices based on D$ ^0$ X transitions.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Consistent gauge theories for the slave particle representation of the strongly correlated $t$-$J$ model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-13 20:00 EDT
Xi Luo, Tao Shi, Yue Yu, Long Liang
This note aims to clarify the confusion and inconsistency, and to address the incompleteness in our recent work [1,2]. In order to avoid the ill-defined nature of the free propagator of the gauge field in the ordered states of the $ t$ -$ J$ model, we adopted a gauge fixing that was not of the Becchi-Rouet-Stora-Tyutin (BRST) exact form in our previous work [2]. This led to the situation where Dirac’s second-class constraints, namely, the slave particle number constraint and the Ioffe-Larkin current constraint, were not rigorously obeyed. Here we show that a consistent gauge fixing condition that enforces the exact constraints must be BRST-exact. An example is the Lorenz gauge. On the other hand, we prove that although the free propagator of the gauge field in the Lorenz gauge is ill-defined, the full propagator is still well-defined. This implies that the strongly correlated $ t$ -$ J$ model can be exactly mapped to a perturbatively controllable theory within the slave particle representation.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages
Cubic magnetic anisotropy in $B$20 magnets: Interplay of anisotropy and magnetic order in Fe${1-x}$Co${x}$Si
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-13 20:00 EDT
G. Gödecke, A. O. Leonov, J. Grefe, S. Süllow, D. Menzel
The metallic systems MnSi and Fe$ _{1-x}$ Co$ _{x}$ Si are known to feature a generic magnetic phase diagram primarily determined by the isotropic exchange and Dzyaloshinskii-Moriya interactions. However, additional weaker anisotropies, lowest in the hierarchy of energy scales, play a crucial role: they determine the relative order of phases in the phase diagram and may even enable skyrmion stability far below the ordering temperature. Among cubic B20 helimagnets, the insulator Cu$ _2$ OSeO$ _3$ is currently the only known example exhibiting a low-temperature, anisotropy-induced skyrmion pocket. In this manuscript, we present a systematic study of cubic magnetocrystalline anisotropy by means of angle-resolved SQUID magnetization measurements in MnSi and Fe$ _{1-x}$ Co$ _{x}$ Si ($ 0.08 \leq x \leq 0.70$ ) single crystals and provide quantitative values of the anisotropy constants. For Fe$ _{1-x}$ Co$ _{x}$ Si, the cubic anisotropy is found to be strongly dependent on the Co concentration $ x$ . In particular, for low Co concentrations ($ x \sim 0.10$ ), the anisotropy is sufficiently strong to stabilize a low-temperature skyrmion lattice, in agreement with theoretical predictions. This finding suggests that Fe$ _{1-x}$ Co$ _{x}$ Si may represent the first chiral metallic system to exhibit a low-temperature skyrmion phase controllably stabilized by cubic anisotropy for specific directions of the magnetic field.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Field-induced magnetic phases in the Kitaev candidate Na$_3$Co$_2$SbO$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-13 20:00 EDT
Kranthi Kumar Bestha (1 and 2), Manaswini Sahoo (1 and 2)Niccolò Francini (3), Robert Kluge (1), Ryan Morrow (1), Andrey Maljuk (1), Sabine Wurmehl (1), Sven Luther (4), Yurii Skourski (4), Hannes Kühne (4), Swarnamayee Mishra (2), Jochen Geck (2), Manuel Brando (5), Bernd Büchner (1 and 2), Laura T. Corredor (1), Lukas Janssen (3), Anja U. B. Wolter (1) ((1) Leibniz IFW Dresden, Institute of Solid State Research, Dresden, Germany, (2) Institut für Festkörper- und Materialphysik and Würzburg-Dresden Cluster of Excellence <a href=”http://ct.qmat“ rel=”external noopener nofollow” class=”link-external link-http”>this http URL</a>, Technische Universität Dresden, Dresden, Germany, (3) Institut für Theoretische Physik and Würzburg-Dresden Cluster of Excellence <a href=”http://ct.qmat“ rel=”external noopener nofollow” class=”link-external link-http”>this http URL</a>, Technische Universität Dresden, Dresden, Germany, (4) Hochfeld-Magnetlabor Dresden, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany, (5) Max Planck Institute for Chemical Physics of Solids, Dresden, Germany)
We report a rich anisotropic magnetic phase diagram of Na$ _3$ Co$ _2$ SbO$ 6$ , a previously proposed cobaltate Kitaev candidate, based on field- and temperature-dependent magnetization, specific heat, and magnetocaloric effect studies. At low temperatures, our experiments uncover a low-lying $ j{\textrm{eff}} = \frac{1}{2}$ state with an antiferromagnetic ground state and pronounced in-plane versus out-of-plane anisotropy. The experimentally identified magnetic phases are theoretically characterized through classical Monte Carlo simulations within an extended Kitaev-Heisenberg model with additional ring exchange interactions. The resulting phase diagram reveals a variety of exotic field-induced magnetic phases, including double-$ \textbf{q}$ , $ \frac{1}{3}$ -AFM, zigzag, and vortex phases.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Clarification of Floquet–Enhanced Thermal Emission Through the Nonequilibrium Green’s Function Formalism
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Yuhua Ren, Hui Pan, Jian-Sheng Wang
Floquet engineering offers a powerful route to enhance emission in time-modulated media. Here, we investigate the influence of time-modulated permittivity in silicon carbide on its intensity spectrum. We consider both the nonequilibrium Green’s function approach and the macroscopic quantum electrodynamics approach, and establish their formal compatibility by deriving the Lippmann-Schwinger equation in both cases. To analyze spectral features, we propose several methods for decomposing the electric field into positive- and negative-frequency components, along with the criteria required for physical consistency. Our analytical and numerical results show that, when defined appropriately, the intensity spectrum avoids divergence, though the resulting enhancement remains modest. These findings provide a unified theoretical foundation for modeling time-dependent media, and reinforce the utility of Floquet engineering as a versatile platform for tailoring emission dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 1 figure
Room-temperature magnetic semiconductor with superhigh hole mobility and ferrotoroidicity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Jianyuan Qi, Shijie Xiong, Beining Ma, Xinghai Shen
The design and fabrication of room-temperature magnetic semiconductors are recognized worldwide as a great challenge, and of both theoretical and practical importance in the field of spintronics. Compared with diluted magnetic semiconductors, intrinsic room-temperature magnetic semiconductors have rarely been developed. Reported herein is a magnetic semiconductor film formed by supramolecular self-assembly based on uranyl and cyclodextrin, with the Curie temperature above room temperature. The electrical measurements show that the film exhibits typical p-type semiconductor characteristics with a superhigh carrier mobility of 3200 cm2V-1s-1, which can help achieve an excellent match with the n-type semiconductor. The room-temperature magnetic semiconductor with superhigh hole mobility can be attributed to the formation of ferrotoroidicity and the highly ordered transport channel. This work paves the way for the application of ferrotoroidic materials in sensing, information storage as well as flexible electronics.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Chemical Physics (physics.chem-ph)
Magnetic Materials for Quantum Magnonics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Rostyslav O. Serha, Carsten Dubs, Andrii V. Chumak
Quantum magnonics studies the quantum properties of magnons, the quanta of spin waves, and their application in quantum information processing. Progress in this field depends on identifying magnetic materials with characteristics tailored to the diverse requirements of magnonics and quantum magnonics. For single-magnon excitation, its control, hybrid coupling, and entanglement, the most critical property is the ability to support long magnon lifetimes. This perspective reviews established and emerging magnetic materials, including ferromagnetic metals, Heusler compounds, antiferromagnets, altermagnets, organic and 2D van der Waals magnets, hexaferrites, and in particular yttrium iron garnet (YIG), highlighting their key characteristics. YIG remains the benchmark, with bulk crystals supporting sub-microsecond Kittel-mode lifetimes and ultra-pure spheres achieving $ \sim18,\mu$ s for dipolar-exchange magnons at millikelvin temperatures. However, thin YIG films on gadolinium gallium garnet (GGG) substrates suffer from severe lifetime reduction due to substrate-induced losses. In contrast, YIG films on a new lattice matched, diamagnetic alternative, yttrium scandium gallium/aluminum garnet (YSGAG), overcomes these limitations and preserves low magnetic damping down to millikelvin temperatures. These advances provide a practical pathway toward ultralong-living magnons in thin films, enabling scalable quantum magnonics with coherent transport, strong magnon-photon, magnon-qubit coupling, and integrated quantum networks.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Configurational Entropy-Driven Phase Stability and Thermal Transport in Rock-Salt High-Entropy Oxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Ashutosh Kumar, Adrien Moll, Jitendra Kumar, Diana Dragoe, David Bérardan, Nita Dragoe
High-entropy oxides (HEOs) offer a unique platform for exploring the thermodynamic interaction between configurational entropy and enthalpy in stabilizing complex solid solutions. In this study, a series of rock-salt structured oxides with varying configurational entropy, ranging from binary to multi-cation systems, to elucidate the competing roles of enthalpy and entropy in phase stabilization is investigated. Compositions including (Ni$ _{0.8}$ Cu$ {0.2}$ )O to(NiCuZnCoMg)$ {0.9}$ A$ {0.1}$ O (A = Li, Na, K) were synthesized and their stuctural, microstructural and thermal properties have been discussed. X-ray diffraction combined with thermal cycling confirms that even a medium configurational entropy ($ \sim$ 0.95R) can induce single-phase behavior stabilized by configurational entropy ($ \Delta S{conf}$ ), challenging the traditional threshold of $ 1.5,R$ . High-resolution TEM and EDS mapping reveal nanocrytalline features and homogeneous elemental distribution respectively, while XPS analysis confirms divalent oxidation states. A strong coupling between high configurational entropy with thermal conductivity ($ \kappa$ ) has been observed. First, a sharp decrease in $ \kappa$ with increasing $ \Delta S{conf}$ is seen and then decomposed samples (while cooling) show high $ \kappa$ , demonstrating the role of $ \Delta S{conf}$ on $ \kappa$ . Furthermore, Li-doped compositions exhibit improved thermoelectric performance, with a maximum figure of merit ($ zT$ ) of $ \sim$ 0.15 at 1173K, driven by low thermal conductivity and favorable carrier transport. The results highlight that configurational entropy, even at intermediate values, plays a significant role in stabilizing disordered single-phase oxides and tailoring phonon transport.
Materials Science (cond-mat.mtrl-sci)
15 Pages, 15 figures, 2 tables
Magnetically Assisted Separation of Weakly Magnetic Metal Ions in Porous Media.Part 1: Experiments
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Alwell Nwachukwu, Muhammad Garba, Jamel Ali, Theo Siegrist, Munir Humayun, Hadi Mohammadigoushki
We report experiments on the magnetophoresis of paramagnetic (MnCl2) and diamagnetic (ZnCl2) metal ions in porous media under the influence of a non-uniform magnetic field generated by a permanent magnet. Experiments were carried out in a range of initial ion concentrations (1-100 mM), porous media particle sizes (63 um and 500 um), and varying mixture ratios of metal ion concentrations. For single-ion magnetophoresis, paramagnetic MnCl2 migrated toward the magnet surface, with an enrichment of approximately 2-4 percent near regions of high magnetic field. Conversely, diamagnetic ZnCl2 moved away from regions of highest magnetic field gradients, with depletion levels of 0.5-1.8 percent relative to the initial concentration. Our results demonstrate that magnetophoresis is directly proportional to porous media particle size, increasing with larger particle sizes, a trend attributed to the reduced drag forces experienced by the ions in media with larger particles. Interestingly, in binary mixtures, both MnCl2 and ZnCl2 migrated toward regions of highest magnetic field, contrary to their individual behaviors. The magnetophoretic effect of MnCl2 was diminished with increasing concentrations of ZnCl2, indicating interactions between the two ions. These findings suggest that both metal ions undergo field-induced cluster formation, with cluster sizes in the micrometer range, in both single and binary ion systems. In binary mixtures, the two ions appear to interact, potentially forming mixed clusters containing both MnCl2 and ZnCl2.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Superconductivity in the repulsive Hubbard model on different geometries induced by density-assisted hopping
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-13 20:00 EDT
Franco T. Lisandrini, Edmond Orignac, Roberta Citro, Ameneh Sheikhan, Corinna Kollath
We study the effect of density-assisted hopping on different dimerized lattice geometries, such as bilayers and ladder structures. We show analytically that the density-assisted hopping induces an attractive interaction in the lower (bonding) band of the dimer structure and a repulsion in the upper (anti-bonding) band. Overcoming the onsite repulsion, this can lead to the appearance of superconductivity. The superconductivity depends strongly on the filling, and present a pairing structure more complex than s-wave pairing. Combining numerical and analytical methods such as the matrix product states ansatz, bosonization and perturbative calculations we map out the phase diagram of the two-leg ladder system and identify its superconducting phase. We characterize the transition from the non-density-assisted repulsive regime to the spin-gapped superconducting regime as a Berezinskii-Kosterlitz-Thouless transition.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con)
Non-Hermitian Bethe-Salpeter Equation for Open Systems: Emergence of Exceptional Points in Excitonic Spectra from First Principles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Zhenlin Zhang, Wei Hu, Enrico Perfetto, Gianluca Stefanucci
In open quantum systems hosting excitons, dissipation mechanisms critically shape the excitonic dynamics, band-structure and topological properties. A microscopic understanding of excitons in such non-Hermitian settings demands a first-principles generalization of the Bethe-Salpeter equation (BSE). Building on a recently introduced nonequilibrium Green’s function formalism compatible with Lindbladian dynamics, we derive a non-Hermitian BSE from diagrammatic perturbation theory on the Keldysh contour, and obtain a microscopic excitonic Hamiltonian that incorporates dissipation while preserving causality. We apply the formalism to valley excitons in transition metal dichalcogenides coupled to structured photon baths. We uncover a rich landscape of exceptional points in momentum space, forming either discrete sets or continuous manifolds, depending on bath structure. The exceptional points give rise to nonanalytic valley-polarization, unusual polarization pattern in photoluminescence, and nontrivial topological signatures. Our results establish a first-principles framework for predicting and controlling excitonic behavior in open quantum materials, showing how engineered environments can be leveraged to induce and manipulate non-Hermitian and topological properties.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
23 pages, 5 figures
Are diffusion models ready for materials discovery in unexplored chemical space?
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Sanghyun Kim, Gihyeon Jeon, Seungwoo Hwang, Jiho Lee, Jisu Jung, Seungwu Han, Sungwoo Kang
While diffusion models are attracting increasing attention for the design of novel materials, their ability to generate low-energy structures in unexplored chemical spaces has not been systematically assessed. Here, we evaluate the performance of two diffusion models, MatterGen and DiffCSP, against three databases: a ternary oxide set (constructed by a genetic algorithm), a ternary nitride set (constructed by template informatics), and the GNoME database (constructed by a combination of both). We find that diffusion models generally perform stably in well-sampled chemical spaces (oxides and nitrides), but are less effective in uncommon ones (GNoME), which contains many compositions involving rare-earth elements and unconventional stoichiometry. Finally, we assess their size-extrapolation capability and observe a significant drop in performance when the number of atoms exceeds the trained range. This is attributed to the limitations imposed by periodic boundary conditions, which we refer to as the curse of periodicity. This study paves the way for future developments in materials design by highlighting both the strength and the limitations of diffusion models.
Materials Science (cond-mat.mtrl-sci)
Deep prior-based denoising for state-of-the-art scientific imaging and metrology
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Yuichi Yokoyama, Kohei Yamagami, Yuta Sumiya, Hayaru Shouno, Masaichiro Mizumaki
Deep learning has revolutionized computer vision, yet a major gap persists between complex, data-hungry deep learning models and the practical demands of state-of-the-art scientific measurements. To fundamentally bridge this gap, we propose deep prior-based denoising, a robust deep learning model that requires no training data. We demonstrate its effectiveness by removing grid artifacts in angle-resolved photoemission spectroscopy (ARPES), a long-standing and critical data analysis challenge in materials science. Our results demonstrate that deep prior-based denoising yields clearer ARPES images in a fraction of the time required by conventional, experiment-based denoising methods. This ultra-efficient approach to ARPES will enable high-speed, high-resolution three-dimensional band structure mapping in momentum space, thereby dramatically accelerating our understanding of microscopic electronic structures of materials. Beyond ARPES, deep prior-based denoising represents a versatile tool that could become a new standard in any advanced scientific measurement fields where data acquisition is limited.
Materials Science (cond-mat.mtrl-sci)
14 pages, 5 figures
Homogeneous and inhomogeneous phases in a numerical model of a time-reversal-breaking superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-13 20:00 EDT
In this manuscript, we find an inhomogeneous stripes phase in a numerical model for an unconventional superconductor with time-reversal-breaking symmetry and triplet odd pairing. We contrast a robust well known homogeneous phase with dilute disorder characterized by a unitary resonance and a tiny gap that resembles an s-wave superconductor, with a new inhomogeneous phase with extremely dilute disorder and real frequency stripes. This phase has only two ultra-small frequency collision values at the edges of the unitary resonance, indicating the displacement of the s-wave tiny gap to the outer edges of the resonance. We perform a statistical analysis of the real frequency density and encounter a lack of spectral stability, characterized by a sequence of vertical frequency stripes. Experimentalists can verify this finding by looking for an unstable phase in extremely clean samples of candidates for triplet superconductors.
Superconductivity (cond-mat.supr-con)
15 pages, 4 figures
Room temperature optical control of spin states in organic diradicals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Rituparno Chowdhury, Alistair Inglis, Lucy E. Walker, Petri Murto, Chiara Delpiano-Cordeiro, Colin Morrison, Naitik A. Panjwani, Yao Fu, Yan Sun, Wei Zhou, Peter J. Skabara, Akshay Rao, Alexei Chepelianskii, Hugo Bronstein, Sam L. Bayliss, Richard H. Friend
We report a family of luminescent alternant diradicals which, at room temperature, support a ground-state spin-triplet, near-unity photoluminescence quantum yields, and optical spin addressability. These diradicals comprise trityl groups meta-linked via pyridyl or phenyl groups, enabling optically bright triplet-to-triplet and singlet-to-singlet transitions. At room temperature, we observe optically detected magnetic resonance in these systems at zero magnetic field and a strong magneto-photoluminescence (10% modulation at 2 mT applied magnetic field). Distinct photoluminescence bands (at 630 nm and 700 nm) show opposite-sign spin-optical responses, arising from spin-selective intersystem crossing between triplet and singlet manifolds. These bright, all-organic diradicals offer a new set of chemically tunable materials for room temperature spin-optical interfaces, paving the way for application as quantum sensors.
Materials Science (cond-mat.mtrl-sci)
18 pages 4 figures
Advances in momentum-resolved EELS of phonons, excitons and plasmons in 2D materials and their heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Cana Elgvin, Fredrik S. Hage, Khairi F. Elyas, Katja Höflich, Øystein Prytz, Christoph T. Koch, Hannah C. Nerl
Functional nanomaterials, including 2D materials and their heterostructures are expected to impact fields ranging from catalysis, optoelectronics to nanophotonics. To realize their potential, novel experimental approaches need to be developed to characterize the combined materials and their components. Techniques using fast electrons, such as electron energy-loss spectroscopy (EELS), probe phenomena over an unrivaled energy range with high resolution. In addition, momentum-resolved EELS simultaneously records energy and momentum transfer to the sample and thus generates two-dimensional data sets for each beam position. This allows excitations that occur at large momentum transfer to be resolved, including those outside of the light cone and beyond the first Brillouin zone, all whilst retaining nanometer sized spatial selectivity. Such capabilities are particularly important when probing phonons, plasmons, excitons and their coupling in 2D materials and their heterostructures.
Materials Science (cond-mat.mtrl-sci)
Deep Learning of the Biswas-Chatterjee-Sen Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-13 20:00 EDT
J. F. Silva Neto, D. S. M. Alencar, L. T. Brito, G. A. Alves, F. W. S. Lima, A. Macedo-Filho, R. S. Ferreira, T. F. A. Alves
We investigate the critical properties of kinetic continuous opinion dynamics using deep learning techniques. The system consists of $ N$ continuous spin variables in the interval $ [-1,1]$ . Dense neural networks are trained on spin configuration data generated via kinetic Monte Carlo simulations, accurately identifying the critical point on both square and triangular lattices. Classical unsupervised learning with principal component analysis reproduces the magnetization and allows estimation of critical exponents. Additionally, variational autoencoders are implemented to study the phase transition through the loss function, which behaves as an order parameter. A correlation function between real and reconstructed data is defined and found to be universal at the critical point.
Statistical Mechanics (cond-mat.stat-mech), Data Analysis, Statistics and Probability (physics.data-an)
11 pages, 8 figures. arXiv admin note: text overlap with arXiv:2509.14155
Self-Consistent Fourier-Tschebyshev Representations of the First Normal Stress Difference in Large Amplitude Oscillatory Shear
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-13 20:00 EDT
Nicholas King, Eugene Pashkovski, Reid Patterson, Paige Rockwell, Gareth H. McKinley
Large Amplitude Oscillatory Shear (LAOS) is a key technique for characterizing nonlinear viscoelasticity in a wide range of materials. Most research to date has focused on the shear stress response to an oscillatory strain input. However, for highly elastic materials such as polymer melts, the time-varying first normal stress difference $ N_1(t;\omega,\gamma_0)$ can become much larger than the shear stress at sufficiently large strains, serving as a sensitive probe of the material’s nonlinear characteristics. We present a Fourier-Tschebyshev framework for decomposing the higher-order spectral content of the $ N_1$ material functions generated in LAOS. This new decomposition is first illustrated through analysis of the second-order and fourth-order responses of the quasilinear Upper Convected Maxwell model and the fully nonlinear Giesekus model. We then use this new framework to analyze experimental data on a viscoelastic silicone polymer and a thermoplastic polyurethane melt. Furthermore, we couple this decomposition with the recently developed Gaborheometry strain sweep technique to enable rapid and quantitative determination of the $ N_1$ material function from experimental normal force data obtained in a single sweep from small to large strain amplitudes. We verify that asymptotic connections between the oscillatory shear stress and $ N_1$ in the quasilinear limit are satisfied for the experimental data, ensuring self-consistency. This framework for analyzing the first normal stress difference is complementary to the established framework for analyzing the shear stresses in LAOS, and augments the content of material-specific data sets, hence more fully quantifying the important nonlinear viscoelastic properties of a wide range of soft materials.
Soft Condensed Matter (cond-mat.soft)
Restoring detailed balance in non-Hermitian Markov processes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-13 20:00 EDT
Tim Van Wesemael, Gilberto Nakamura, Jan Baetens, Odemir M. Bruno, Alexandre S. Martinez, Christophe Deroulers
Stochastic processes out-of-equilibrium often involve asymmetric contributions that break detailed balance and lead to non-monotonic entropy production, limiting thermodynamic interpretations and inference techniques. Here we use Dyson maps to restore monotonic entropy growth in those processes, allowing the use of standard tools from statistical physics, providing a general and computationally tractable method applicable to a broad class of Markovian systems.
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 6 figures
Acoustic transparency in dense granular suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-13 20:00 EDT
Arnaud Tourin, Yamil Abraham, Marie Palla, Arthur Le Ber, Romain Pierrat, Nicolas Benech, Carlos Negreira, Xiaoping Jia
We demonstrate the existence of a frequency band exhibiting acoustic transparency in 2D and 3D dense granular suspensions, enabling the transmission of a low-frequency ballistic wave excited by a high-frequency broadband ultrasound pulse. This phenomenon is attributed to spatial correlations in the structural disorder of the medium. To support this interpretation, we use an existing model that incorporates such correlations via the structure factor. Its predictions are shown to agree well with those of the Generalized Coherent Potential Approximation (GCPA) model, which is known to apply at high volume fractions, including the close packing limit, but does not explicitly account for disorder correlation. Within the transparency band, attenuation is found to be dominated by absorption rather than scattering. Measurements of the frequency dependence of the absorption coefficient reveal significant deviations from conventional models, challenging the current understanding of acoustic absorption in dense granular media.
Soft Condensed Matter (cond-mat.soft)
Toggling stiffness via multistability
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-13 20:00 EDT
Hugo de Souza Oliveira, Michele Curatolo, Renate Sachse, Edoardo Milana
Mechanical metamaterials enable unconventional and programmable mechanical responses through structural design rather than material composition. In this work, we introduce a multistable mechanical metamaterial that exhibits a toggleable stiffness effect, where the effective shear stiffness switches discretely between stable configurations. The mechanical analysis of surrogate beam models of the unit cell reveal that this behavior originates from the rotation transmitted by the support beams to the curved beam, which governs the balance between bending and axial deformation. The stiffness ratio between the two states of the unit cell can be tuned by varying the slenderness of the support beams or by incorporating localized hinges that modulate rotational transfer. Experiments on 3D-printed prototypes validate the numerical predictions, confirming consistent stiffness toggling across different geometries. Finally, we demonstrate a monolithic soft clutch that leverages this effect to achieve programmable, stepwise stiffness modulation. This work establishes a design strategy for toggleable stiffness using multistable metamaterials, paving the way for adaptive, lightweight, and autonomous systems in soft robotics and smart structures.
Soft Condensed Matter (cond-mat.soft), Robotics (cs.RO), Applied Physics (physics.app-ph)
A microscopic approach to nonlinear theory of spin-charge separation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-13 20:00 EDT
Oleksandr Tsyplyatyev, Yiqing Jin, María Moreno, Wooi Kiat Tan, Christopher J.B. Ford
The fate of spin-charge separation beyond the low energy remains elusive up to now. Here we develop a microscopic theory of the correlation functions using the strong coupling expansion of the Hubbard model and demonstrate its validity down to the experimentally relevant $ r_{\rm s}>1$ . Evaluating the spectral function, we show the general stability of the nonlinear spin-charge modes in whole energy band and investigate all the nonlinear features systematically. We confirm the general prediction experimentally in semiconductor quantum wires. Furthermore, we observe a signal consistent with a continuum of the nonlinear excitations and with a final spectral density around the $ 3 k_{\rm F}$ point, indicating the robustness of the Hubbard model predictions for a finite range interaction.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
28 pages, 5 figures
Is Platinum a Proton Blocking Catalyst?
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Aparna Saksena, Yujun Zhao, J. Manoj Prabhakar, Dierk Raabe, Baptiste Gault, Yug Joshi
Platinum, to date, is the most widely applied electrocatalyst for hydrogen evolution reaction (HER) in acidic media. It is assumed to be a proton-blocking catalyst with only surface-limited adsorption of the reaction intermediates. Here, we critically evaluate the bulk interaction of Pt with hydrogen (H), and its heavier isotope deuterium (D), by monitoring operando mass change of the Pt electrode during galvanostatic heavy/water splitting by employing an electrochemical quartz crystal microbalance. Unexpectedly, we observe an irreversible temporal mass gain and a change in the reaction’s overpotential, arising from diffusion of H/D into Pt, confirmed by atom probe tomography and thermal desorption spectroscopy. Sub-surface concentration of at least ca. 15 at. % of D in Pt was observed, diffusing down to a depth of more than 10 nm. Analytical description quantified the diffusion coefficient of D in Pt to be 3.2X10^-18 cm2Xs-1. These findings challenge the existing credence of Pt-proton interaction being limited to the surface, prompting the expansion of the catalyst design strategies to account for property-modifying bulk diffusion of H/D in the Pt matrix
Materials Science (cond-mat.mtrl-sci)
Optically induced orbital polarization in bulk germanium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Francesco Scali, Marco Finazzi, Federico Bottegoni, Carlo Zucchetti
Optical orientation has been proven as a powerful tool to inject spin-polarized electron and hole populations in III-V and group-IV semiconductors. In particular, the absorption of circularly-polarized light in bulk Ge generates a spin-oriented population of electrons in the conduction band with a spin-polarization up to 50%, whereas the hole spin-polarization, opposite to the electron one, can even reach values up to 83%. In this letter, we theoretically investigate the optical injection of orbital polarization by means of circularly-polarized light in bulk Ge and we show that the latter considerably exceeds 100% for holes and photon energies close to the direct Ge gap. These results suggest that Ge is a convenient platform for future development of orbitronics and opto-orbitronic devices.
Materials Science (cond-mat.mtrl-sci)
Insights into the OER, ORR, and HER Activity of a New MXene-Family SnSiGeN4 Photocatalyst for Water Splitting: A First-Principles Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Chhatra Bahadur Subba, Bhanu Chettri, Amel Laref, Zeesham Abbas, Amna Parveen, Dibya Prakash Rai, Zaithanzauva Pachuau
The development of efficient and cost-effective catalysts for clean energy conversion remains a central challenge in materials science. Although platinum serves as the benchmark catalyst, its scarcity and high cost hinder large-scale deployment. In this study, we propose a newly predicted SnSiGeN4 MXene-family monolayer as a promising candidate for the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER). Using first-principles calculations, we systematically investigated its electronic, vibrational, and optical properties across multiple exchange-correlation functionals, including hybrid approaches, revealing a wide and tunable band gap. Simulated infrared and Raman spectra further confirm the dynamical stability and the presence of catalytically active sites. Guided by these findings, we studied photocatalytic reaction analyses that demonstrate that the computed overpotentials for OER, ORR, and HER are comparable to those of Pt-based catalysts and outperform Ir-based systems, positioning SnSiGeN4 as a sustainable, high-performance platform for next-generation UV-visible-light-driven photocatalysis.
Materials Science (cond-mat.mtrl-sci)
Mapping the moiré potential in multi-layer rhombohedral graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-13 20:00 EDT
Eric Seewald, Sanat Ghosh, Nishchhal Verma, John Cenker, Yinan Dong, Birui Yang, Amit Basu, Takashi Taniguchi, Kenji Watanabe, Mandar M. Deshmukh, Dmitri N. Basov, Raquel Queiroz, Cory Dean, Abhay N. Pasupathy
Rhombohedral graphene (rG) aligned with hexagonal boron nitride (hBN) has been shown to host flat bands that stabilize various strongly correlated quantum phases, including Mott insulators, integer, and fractional quantum anomalous Hall phases. In this work, we use scanning tunneling microscopy/spectroscopy (STM/STS) to visualize the dispersion of flat bands with doping and applied displacement fields in a hBN-aligned rhombohedral trilayer graphene (rtG)/hBN moiré superlattice. In addition to the intrinsic flat bands of rtG induced by the displacement field, we observe low-energy features originating from moiré potential-induced band folding. Real-space variations of the spectroscopic features allow us to quantify the spatial structure of the moiré potential at the rtG/hBN interface. Importantly, we find that accurately capturing the moiré site-dependent spectra requires incorporating a moiré potential acting on the top graphene layer with a sign opposite to that of the bottom layer into the continuum model. Our results thus provide key experimental and theoretical insights into understanding the role of the moire superlattice in rG/hBN heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Anomalous Diffusion in a Percolating Disordered Dipolar Spin Ensemble
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-10-13 20:00 EDT
Andrew Stasiuk, Garrett Heller, Lance Berkey, Bo Xing, Paola Cappellaro
Emergent hydrodynamics (EHD) bridges short-time unitarity with late-time thermodynamics, universal transport phenomena characterize the manner and speed of transport and thermalization. Typical non-integrable systems with few conserved local quantities are expected to be diffusive. In contrast, strongly disordered systems which admit phases such as many-body localization, are predicted to inhibit thermalization and thus slow dynamical transport. Disordered systems represent a uniquely poised platform to probe the quantum-to-classical transition and the emergence of irreversible thermodynamics from the underlying unitary structure. Here, we study a strongly disordered nuclear spin ensemble, using local measurements enabled by the disordered-state technique. We observe an apparent phase transition into a sub-diffusive regime, which we model as a random walk on the emergent fractal structure of a percolating network in the dipolar spin ensemble. Our novel theoretical model provides a framework for characterizing the emergence of thermalization in closed quantum systems, even in the presence of strong disorder.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
7 pages, 1 figure main text
Orientational Order of Phenyl Rotors on Triangular Platforms on Ag and Au(111)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Behzad Mortezapour, Sebastian Hamer, Rainer Herges, Roberto Robles, Richard Berndt
We investigated trioxatriangulenium functionalized with phenyl (phenyl-TOTA) on the (111) surfaces of Ag and Au using low-temperature scanning tunneling microscopy (STM) and density functional theory (DFT). On Ag(111), the molecules form hexagonal arrays, and on Au(111), honeycomb patterns are also observed. The orientations of the phenyl moieties are resolved on both substrates. On Ag(111), the orientations are parallel within a row and they differ by approximately $ 60^\circ$ between adjacent molecular rows, and STM images suggest dimerization of the molecules. DFT calculations for Ag(111) reveal that van der Waals interactions dominate this system. The optimized structure matches the experimental pattern, and the simulated STM images exhibit apparent dimerization. This dimerization results from an asymmetry of the phenyl wavefunction, which reflects intramolecular hydrogen bonding between the ligand and an oxygen atom within the triangulenium platform. The orientation of the phenyl moieties is explained by the interaction of each phenyl moiety with its triangulenium platform combined with the direct long-range interaction between phenyl moieties across molecules.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Ab initio study on photocatalytic properties of PtSSe-WXY Janus heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-13 20:00 EDT
Shivprasad S. Shastri, Antonio Cammarata, Tomas Polcar
Semiconductor photocatalysis offers a sustainable route for converting solar energy into chemical energy, enabling the production of clean fuels and valuable chemical products. To this aim, we explore van der Waals heterostructures made up of Janus PtSSe and WXY (X, Y $ =$ S, Se, Te and X $ \neq$ Y), in the context of photocatalytic applications. The redox capabilities of various heterostructure configurations (atom facing types and stacking orders) are evaluated by aligning the absolute band edge positions with respect to redox potentials of hydrogen and oxygen evolution reaction (HER and OER) and CO$ _2$ reduction reactions. The stability of photocatalyst candidates are checked by layer binding energy calculations and ab initio molecular dynamics simulations. The optical absorption spectra suggest good light absorption in the visible range. Further, strain engineering is applied as a way to tune band edges and evaluate the possible use of the heterostructures as photocatalysts. This study shows that van der Waals heterostructure bilayers composed of Janus PtSSe and WSeTe in specific geometric configurations can be potential materials as photocatalysts for HER, OER and CO$ _2$ reduction reactions. Finally, we suggest that, although systems made up of PtSSe and WSTe cannot be used for photocatalytic applications, they can be explored for applications in thermoelectric energy conversion or infrared photovoltaics.
Materials Science (cond-mat.mtrl-sci)