CMP Journal 2025-10-07
Statistics
Nature Nanotechnology: 2
Nature Physics: 1
Physical Review Letters: 21
Physical Review X: 1
arXiv: 90
Nature Nanotechnology
Tailoring nanoscale interfaces for perovskite-perovskite-silicon triple-junction solar cells
Original Paper | Devices for energy harvesting | 2025-10-06 20:00 EDT
Jianghui Zheng, Guoliang Wang, Leiping Duan, Weiyuan Duan, Yang Jiang, Phoebe Pearce, Yijun Gao, Md Arafat Mahmud, Chwenhaw Liao, Tik Lun Leung, Jueming Bing, Zhuofeng Li, Zhenyu Sun, Xin Cui, Christopher Bailey, Marko Jankovec, Jianpeng Yi, Runmin Tao, Lijie Zheng, Baihong Zhu, Yue Sun, Nan Sun, Gaosheng Huang, Li Wang, Andreas Lambertz, Stephen Bremner, Xinqin Liao, Tingzhu Wu, Guohua Xie, Mathias Uller Rothmann, Marko Topič, David R. McKenzie, Kaining Ding, Wei Li, Zhong Chen, Anita W. Y. Ho-Baillie
Triple‐junction solar cells theoretically outperform their double-junction and single‐junction counterparts in power conversion efficiency, yet practical perovskite-perovskite-silicon devices have fallen short of both theoretical limits and commercial targets. To address surface defects in the top perovskite junction, we introduce a piperazine-1,4-diium chloride treatment, which replaces less stable lithium fluoride. For interfacing the top and middle perovskite junctions, we optimize the size of gold nanoparticles deposited on atomic layer-deposited tin oxide for best ohmic contacting with minimal optical losses. Applying these strategies, our champion 1-cm2 triple‐junction cell achieved a third party-verified reverse‐scan power conversion efficiency of 27.06% with an open circuit voltage of 3.16 V. Scaling up to 16 cm2, the device produced a certified steady‐state power conversion efficiency of 23.3%. Device longevity also improved by eliminating methylammonium and incorporating rubidium into the perovskite bulk alongside the piperazine-1,4-diium chloride surface layer. An encapsulated 1-cm2 cell retained 95% of its initial efficiency after 407 h at maximum power point and passed the IEC 61215 thermal cycling test. These results represent advancements towards efficient and stable perovskite-perovskite-silicon triple-junction solar cells.
Devices for energy harvesting, Electronic devices, Electronic properties and materials
Low-iridium stabilized ruthenium oxide anode catalyst for durable proton-exchange membrane water electrolysis
Original Paper | Chemical engineering | 2025-10-06 20:00 EDT
Chang Qiu, Chase Sellers, Zhen-Yu Wu, David A. Cullen, Eli Stavitski, Akhil Tayal, Tae-Ung Wi, Mounika Kodali, Bryan Erb, Andrew Smeltz, Feng-Yang Chen, Yuge Feng, Zhou Yu, Ahmad Elgazzar, Tanguy Terlier, Thomas P. Senftle, Haotian Wang
While mixing iridium (Ir) with ruthenium oxide (RuO2) has proven to be an effective strategy for reducing Ir loading in anode catalysts for proton-exchange membrane (PEM) water electrolysers, achieving industrially relevant long-term stability typically requires an Ir-rich, Ru-lean combination. Here, by combining density functional theory with Metropolis Monte Carlo methods, we discovered that sufficient stabilization in the RuO2 lattice could be achieved with less than 50 at.% of Ir, and that Ir in the first subsurface layer plays a critical role. By effectively dispersing Ir dopants within the RuO2 lattice, we demonstrated an Ir:Ru atomic ratio of only 1:6 that exhibited exceptional stability for over 1,500 h of continuous water electrolysis at 2 A cm-2. Our Ru6IrOx catalyst has the potential to reduce Ir loading by 80% compared with current commercial PEM water electrolysers, and its stability was further validated under industrial testing conditions in a 25-cm2 PEM electrolyser.
Chemical engineering, Electrocatalysis, Nanoparticles
Nature Physics
Unified theory of phonon in solids with phase diagram of non-Debye anomalies
Original Paper | Condensed-matter physics | 2025-10-06 20:00 EDT
Gan Ding, En Ma, Feng Jiang, Jun Duan, Songlin Cai, Ning Xu, Bingyu Cui, Lanhong Dai, Minqiang Jiang
The classical Debye model successfully predicts phononic contribution to the specific heat of solids in the continuum limit. However, as the phonon wavenumber increases, their vibrational density of states gradually deviates from the Debye prediction and eventually manifests as Van Hove singularities for crystals and a boson peak for glasses. So far, there is still much controversy over whether these two non-Debye anomalies are equivalent or not. Here we propose a unified model and demonstrate that it describes the vibrational density of states in both crystals and glasses. We achieve this by treating the vibrational excitation of solids as the elastic phonons resonating with local modes. Our modelling enables the construction of a phase diagram of non-Debye phonon anomalies. We clarify that the Van Hove singularity and boson peak can evolve as two variants of the same entity when the dispersion displays continuous softening; otherwise, they emerge separately due to resonance-induced extra acoustic softening, further proving by their coexistence. The model is supported by a comparison with experimental heat capacity data over a wide range of real solids, including 143 crystalline and glassy substances. These findings provide a unified picture of the Van Hove singularity and boson peak, and deepen our fundamental understanding of the continuum elasticity of real solids.
Condensed-matter physics
Physical Review Letters
High-Efficiency Plasma-Based Compressor for Ultrafast Soft X-Ray Free-Electron Lasers
Article | Plasma and Solar Physics, Accelerators and Beams | 2025-10-07 06:00 EDT
Mingchang Wang, Li Zeng, Bingbing Zhang, Qinghao Zhu, Xiaozhe Shen, Xiaofan Wang, Qinming Li, and Weiqing Zhang
The generation of intense, femtosecond-scale x-ray pulses is crucial for probing matter under extreme temporal and field conditions. Current chirped-pulse amplification (CPA) techniques in free-electron lasers (FELs), however, face efficiency limitations in the soft x-ray regime due to the inherent …
Phys. Rev. Lett. 135, 155001 (2025)
Plasma and Solar Physics, Accelerators and Beams
Artificial Gauge Field Engineered Excited-State Topology: Control of Dynamical Evolution of Localized Spinons
Article | Condensed Matter and Materials | 2025-10-07 06:00 EDT
Jie Ren, Yi-Ran Xue, Run-Jia Luo, Rui Wang, and Baigeng Wang
Spinons are elementary excitations at the core of frustrated quantum magnets. Although it is well established that a pair of spinons can emerge from a magnon via deconfinement, controlled manipulation of individual spinons and direct observation of their deconfinement remain elusive. We propose an a…
Phys. Rev. Lett. 135, 156601 (2025)
Condensed Matter and Materials
Prediction of Room Temperature Ferroelectricity in Subnano Silicon Thin Films with an Antiferroelectric Ground State
Article | Condensed Matter and Materials | 2025-10-07 06:00 EDT
Hongyu Yu, Shihan Deng, Haiyan Zhu, Muting Xie, Yuwen Zhang, Xizhi Shi, Jianxin Zhong, Chaoyu He, and Hongjun Xiang
Recent advancements highlight the critical need for ferroelectric (FE) materials compatible with silicon, particularly pure silicon phases exhibiting FE behavior above room temperature that can be readily integrated onto silicon substrates. Here, we systematically predict potential FE silicon films …
Phys. Rev. Lett. 135, 156801 (2025)
Condensed Matter and Materials
Surface-Mediated Ultrastrong Cavity Coupling of Two-Dimensional Itinerant Electrons
Article | Condensed Matter and Materials | 2025-10-07 06:00 EDT
Christian J. Eckhardt, Andrey Grankin, Dante M. Kennes, Michael Ruggenthaler, Angel Rubio, Michael A. Sentef, Mohammad Hafezi, and Marios H. Michael
Engineering phases of matter in cavities requires effective light-matter coupling strengths that are on the same order of magnitude as the bare system energetics, coined the ultrastrong coupling regime. For models of itinerant electron systems, which do not have discrete energy levels, a clear defin…
Phys. Rev. Lett. 135, 156902 (2025)
Condensed Matter and Materials
Nonequilibrium Critical Scaling of a Squeezing Phase Transition
Article | Quantum Information, Science, and Technology | 2025-10-06 06:00 EDT
Arman Duha, Samuel E. Begg, and Thomas Bilitewski
We investigate phase transitions in the nonequilibrium dynamics of power-law interacting spin- bilayer XXZ models, which have recently been shown to allow generation of entanglement in the form of two-mode squeezing. We find a transition between a collective phase characterized by Heisenberg limi…
Phys. Rev. Lett. 135, 150401 (2025)
Quantum Information, Science, and Technology
Counting the Ground State Degeneracy by Evolution Methods
Article | Quantum Information, Science, and Technology | 2025-10-06 06:00 EDT
Zhen Guo and Li You
Counting ground state degeneracy of a -local Hamiltonian is important in many fields of physics. Its complexity class is harder than that of finding the ground state of a -local Hamiltonian. Very few methods can efficiently count the degeneracy of ground state while many are known for finding the …
Phys. Rev. Lett. 135, 150601 (2025)
Quantum Information, Science, and Technology
Experimental Efficient Source-Independent Quantum Secret Sharing against Coherent Attacks
Article | Quantum Information, Science, and Technology | 2025-10-06 06:00 EDT
Yi-Ran Xiao, Hua-Lei Yin, Wen-Ji Hua, Xiao-Yu Cao, and Zeng-Bing Chen
Source-independent quantum secret sharing (SI QSS), while essential for secure multi-user cryptographic operations in quantum networks, faces significant implementation challenges stemming from the inherent complexity of generating and distributing multipartite entangled states. Recently, a resource…
Phys. Rev. Lett. 135, 150801 (2025)
Quantum Information, Science, and Technology
Nonlinearly Self-Interacting Extended Bodies Move as Test Bodies in Effective External Fields
Article | Cosmology, Astrophysics, and Gravitation | 2025-10-06 06:00 EDT
Abraham I. Harte, Francisco M. Blanco, and Éanna É. Flanagan
In electromagnetism, linearized general relativity, and other contexts, previous work has shown that the laws of motion which govern compact, self-interacting bodies can be obtained by applying "Detweiler-Whiting prescriptions" to the laws of motion that govern test bodies. These prescriptions repla…
Phys. Rev. Lett. 135, 151401 (2025)
Cosmology, Astrophysics, and Gravitation
Search for ${B}^{0}→{K}^{*0}{τ}^{+}{τ}^{-}$ Decays at the Belle II Experiment
Article | Particles and Fields | 2025-10-06 06:00 EDT
I. Adachi et al. (Belle II Collaboration)
We present a search for the rare flavor-changing neutral-current decay with data collected by the Belle II experiment at the SuperKEKB electron-positron collider. The analysis uses a data sample recorded at the center-of-mass energy of the resonance. One of the mesons pr…
Phys. Rev. Lett. 135, 151801 (2025)
Particles and Fields
Probing Dipolar Interactions between Rydberg Atoms and Ultracold Polar Molecules
Article | Atomic, Molecular, and Optical Physics | 2025-10-06 06:00 EDT
Lingbang Zhu, Jeshurun Luke, Roy Shaham, Yi-Xiang Liu, and Kang-Kuen Ni
We probe resonant dipolar interactions between ultracold molecules and Rydberg atoms in an optically trapped ensemble. Through state-selective ionization detection of the KRb molecules, we observe resonant energy transfer at 2.227 GHz from Rydberg atoms to molecules under a tunable exte…
Phys. Rev. Lett. 135, 153001 (2025)
Atomic, Molecular, and Optical Physics
Series of Molecularlike Doubly Excited States of a Quasi-Three-Body Coulomb System
Article | Atomic, Molecular, and Optical Physics | 2025-10-06 06:00 EDT
M. Génévriez, M. Jungers, C. Rosen, and U. Eichmann
We investigated resonant multiphoton excitation of high-angular-momentum doubly excited states of the strontium atom, a quasi-three-body Coulomb system, both experimentally and theoretically. A series of highly doubly excited states converging to the double ionization threshold was identified and re…
Phys. Rev. Lett. 135, 153002 (2025)
Atomic, Molecular, and Optical Physics
Self-Bound Superfluid Membranes and Monolayer Crystals of Ultracold Polar Molecules
Article | Atomic, Molecular, and Optical Physics | 2025-10-06 06:00 EDT
Matteo Ciardi, Kasper Rønning Pedersen, Tim Langen, and Thomas Pohl
We investigate the physics of ultracold dipolar molecules using path-integral quantum Monte Carlo simulations, and construct the complete phase diagram extending from weak to strong interactions and from small to mesoscopic particle numbers. Our calculations predict the formation of self-bound quant…
Phys. Rev. Lett. 135, 153401 (2025)
Atomic, Molecular, and Optical Physics
Multiplexed Scanning Microscopy with Dual-Qubit Spin Sensors
Article | Atomic, Molecular, and Optical Physics | 2025-10-06 06:00 EDT
William S. Huxter, Federico Dalmagioni, and Christian L. Degen
Scanning probe microscopy with multiqubit sensors offers the potential to improve imaging speed and measure previously inaccessible quantities, such as two-point correlations. We develop a multiplexed quantum sensing approach with scanning probes containing two nitrogen-vacancy (NV) centers at the t…
Phys. Rev. Lett. 135, 153801 (2025)
Atomic, Molecular, and Optical Physics
Enhancement to Fusion Reactivity in Sheared Flows
Article | Plasma and Solar Physics, Accelerators and Beams | 2025-10-06 06:00 EDT
Henry Fetsch and Nathaniel J. Fisch
Sheared flow increases the reactivity of fusion plasma. In unmagnetized plasma with flow gradients comparable to the mean free path of reacting ions, fusion reactivity can be more than doubled. The effect is of particular relevance to inertial confinement fusion (ICF), where it allows implosion kine…
Phys. Rev. Lett. 135, 155101 (2025)
Plasma and Solar Physics, Accelerators and Beams
Resolving Elementary Steps of Vapor-Phase Dealloying via In Situ Transmission Electron Microscopy
Article | Condensed Matter and Materials | 2025-10-06 06:00 EDT
Xinyao Wang, Yanying Li, Yuqiao Zeng, Yanyue Wang, Mingwei Chen, Qing Chen, and Pan Liu
Nanopores evolve in dealloying to dictate alloy corrosion while enabling the creation of functional metallic nanomaterials. Yet, the nanoscale dynamics of the porosity evolution have long eluded experimental characterizations. With aberration-corrected transmission electron microscopy, we reveal the…
Phys. Rev. Lett. 135, 156201 (2025)
Condensed Matter and Materials
Electronic Correlations in Rhombohedral Graphene at Atomic Scale
Article | Condensed Matter and Materials | 2025-10-06 06:00 EDT
Yufeng Liu, Zonglin Li, Shudan Jiang, Min Li, Yu Gu, Kai Liu, Qia Shen, Liang Liu, Xiaoxue Liu, Dandan Guan, Yaoyi Li, Hao Zheng, Canhua Liu, Kenji Watanabe, Takashi Taniguchi, Jinfeng Jia, Tingxin Li, Guorui Chen, Jianpeng Liu, Can Li, Zhiwen Shi, and Shiyong Wang
Rhombohedral graphene (RG) has emerged as a promising platform for exploring exotic quantum phenomena, such as quantum magnetism, unconventional superconductivity, and fractional quantum anomalous Hall effects. Despite its potential, atomic-scale investigations of RG remain limited, hindering a deta…
Phys. Rev. Lett. 135, 156401 (2025)
Condensed Matter and Materials
Quantum Oscillations in the Heat Capacity of Kondo Insulator ${\mathrm{YbB}}_{12}$
Article | Condensed Matter and Materials | 2025-10-06 06:00 EDT
Kuan-Wen Chen, Yuan Zhu, Danilo Ratkovski, Guoxin Zheng, Dechen Zhang, Aaron Chan, Kaila Jenkins, Joanna Blawat, Tomoya Asaba, Fumitoshi Iga, Chandra M. Varma, Yuji Matsuda, John Singleton, Alimamy F. Bangura, and Lu Li
We observe magnetic quantum oscillations in the heat capacity of the Kondo insulator . The frequency of these oscillations, , agrees with that from magnetoresistance and torque magnetometry experiments for in the Kondo insulating phase. Remarkably, the quantum-oscillation a…
Phys. Rev. Lett. 135, 156501 (2025)
Condensed Matter and Materials
Strongly Inhomogeneous Spin Dynamics Induced by Ultrashort Laser Pulses with a Gradient Intensity Profile
Article | Condensed Matter and Materials | 2025-10-06 06:00 EDT
T. T. Gareev, N. E. Khokhlov, L. Körber, and A. V. Kimel
The optical pump-probe technique is a common tool for the investigation of ultrafast spin dynamics, which usually utilizes single-diode detection averaging the dynamics over the pumped area. Using an ultrafast imaging technique, we show experimentally that a femtosecond laser pulse with a gradient d…
Phys. Rev. Lett. 135, 156701 (2025)
Condensed Matter and Materials
Twist Engineering of Anisotropic Excitonic and Optical Properties of a Two-Dimensional Magnetic Semiconductor
Article | Condensed Matter and Materials | 2025-10-06 06:00 EDT
Qiuyang Li, Xiaohan Wan, Senlei Li, Adam Alfrey, Wenhao Liu, Zixin Zhai, Wyatt Alpers, Yujie Yang, Irmina Wladyszewska, Christiano W. Beach, Liuyan Zhao, Bing Lv, Chunhui Rita Du, Kai Sun, and Hui Deng
The anisotropic lattice, spin, and exciton properties of CrSBr monolayers provide the necessary conditions for continuously tunable magnetic moments, exciton energy, and dielectric and optical anisotropies.
Phys. Rev. Lett. 135, 156901 (2025)
Condensed Matter and Materials
Nearly Temperature-Independent Gate-Electric-Field-Driven Lateral Migration of Electrons in ${\mathrm{Si}}{3}{\mathrm{N}}{4}$ Charge Trap Layer of Flash Memory Devices
Article | Condensed Matter and Materials | 2025-10-06 06:00 EDT
Joon Hwang, Min-Kyu Park, Joonhyung Cho, Yeongheon Yang, Jong-Ho Bae, and Jong-Ho Lee
Through experiments and a proposed model, we revealed for the first time why electrons laterally migrate within the charge trap layer during the programming of flash memory devices. The proposed thermally assisted trap-to-band tunneling emission model well explained the measured electric field…
Phys. Rev. Lett. 135, 157001 (2025)
Condensed Matter and Materials
Motility-Induced Crystallization and Rotating Crystallites
Article | Polymers, Chemical Physics, Soft Matter, and Biological Physics | 2025-10-06 06:00 EDT
Max Philipp Holl, Alina Barbara Steinberg, Michael te Vrugt, and Uwe Thiele
Active soft matter frequently shows motility-induced phase separation, where self-propelled particles condensate into clusters with an inner liquidlike structure. Such activity may also result in motility-induced crystallization into clusters with an inner crystalline structure. We derive a higher-o…
Phys. Rev. Lett. 135, 158301 (2025)
Polymers, Chemical Physics, Soft Matter, and Biological Physics
Physical Review X
Experimental Signatures of a New Channel of the Deuteron-Deuteron Reaction at Very Low Energy
Article | | 2025-10-07 06:00 EDT
R. Dubey, K. Czerski, Gokul Das H., A. Kowalska, N. Targosz-Sleczka, M. Kaczmarski, and M. Valat
Deuteron-deuteron fusion at energies below 5 keV occurs mainly via a helium-4 resonance that decays by emitting electron-positron pairs, a newly observed, dominant reaction channel important for stellar nucleosynthesis and fusion models.
Phys. Rev. X 15, 041004 (2025)
arXiv
Proper Theory of Magnon Orbital Angular Momentum
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
The orbital motion of chargeless bosons, unlike that of electrons, does not generate a magnetic moment and thus cannot directly interact with magnetic fields. Utilizing the Aharonov-Casher effect and perturbation theory, we formulate a proper theory for the magnon orbital angular momentum (OAM) at finite temperatures, explicitly identifying both self-rotation and topological contributions, analogous to the electronic counterpart but with correct bosonic statistics. Comparing with previous studies on magnon OAM, the magnon spin Nernst effect can only be correctly reproduced using the proper theory for magnon OAM. In a two-dimensional honeycomb lattice, we show that the Dzyaloshinskii-Moriya interaction induces a large magnon OAM in both ferromagnetic and antiferromagnetic ground states. Our formulation provides a foundation for studying orbital dynamics of chargeless bosons with intrinsic spin.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Electron-beam-induced Contactless Manipulation of Interlayer Twist in van der Waals Heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Nicola Curreli, Tero S. Kulmala, Riya Sebait, Nicolò Petrini, Matteo Bruno Lodi, Roman Furrer, Alessandro Fanti, Michel Calame, Ilka Kriegel
The ability to dynamically control the relative orientation of layers in two dimensional (2D) van der Waals (vdW) heterostructures represents a critical step toward the realization of reconfigurable nanoscale devices. Existing actuation methods often rely on mechanical contact, complex architectures, or extreme operating conditions, which limit their applicability and scalability. In this work, we present a proof-of-concept demonstration of contactless electrostatic actuation based on electron-beam-induced charge injection. By locally charging an insulating hexagonal boron nitride (hBN) flake on an electrically grounded graphene layer, we create an interfacial electric field that generates in-plane electrostatic torque and induces angular displacement. We validate the induced rotation through in-situ scanning electron microscopy (SEM) and twist-dependent Raman spectroscopy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Coherent matter wave emission from an atomtronic transistor
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-10-07 20:00 EDT
Sasanka Dowarah, Mengxin Du, Alan Zanders, Shengwang Du, Michael Kolodrubetz, Chuanwei Zhang
The atomtronic matter-wave triple-well transistor is theoretically predicted to exhibit current gain and act as a coherent matter-wave emitter. In this work, we investigate the dynamics of an atomtronic transistor composed of a triple-well potential – source, gate, and drain – modeled by the time-dependent Gross-Pitaevskii equation. We systematically explore the dependence of the drain population and the current on the source bias potential and the strength of the interatomic interaction. Our simulations reveal signatures of resonant tunneling when the source chemical potential aligns with discrete energy levels in the gate well, leading to coherent matter-wave emission in the drain. Contrary to previous many-body studies that predicted interaction-induced current gain via coupling to gate well modes, our results suggest that coherence in the drain is primarily governed by single-particle resonances, with no evident broadening from nonlinear coupling.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
7 pages, 5 figures
Spin-orbit coupling and the Edelstein effect at conducting ferroelectric domain walls
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Maryam A. Nasir, W. A. Atkinson
Head-to-head ferroelectric domain walls are intrinsically charged, and are typically compensated by a mix of oppositely charged defects and free electrons. The free electrons form a two-dimensional electron gas (2DEG) along the domain wall. In many cases, inversion symmetry is broken at the wall, which implies that the 2DEG is subject to nontrivial spin-orbit coupling. Here, we use symmetry arguments to construct a generic six-band tight-binding electronic Hamiltonian for a $ 90^\circ$ head-to-head ferroelectric domain wall. The model, which includes spin-orbit physics and has a multi-orbital $ t_{2g}$ band structure that is common to transition-metal perovskites, is applied to BaTiO$ _3$ . We find that the 2DEG develops an Ising spin texture, with spins aligned perpendicular to the domain wall. We contrast this with the Rashba spin texture that should emerge at weakly conducting $ 90^\circ$ head-to-tail domain walls. We then show that the head-to-head domain walls should have a measurable Edelstein effect (that is, a current-induced magnetization), even in the dilute limit and at room temperature, and describe a simple experiment to measure it.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Pure many-body interactions in colloidal systems by artificial random light fields
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Augustin Muster, Luis S. Froufe-Pérez
We propose a method to generate pure many-body interactions in colloidal systems by using optical forces induced by random optical fields with an optimized spectral energy density. To assess the feasibility in general settings, we develop a simple model for Lorentzian electric and magnetic dipole response. An optimization procedure is then introduced to design the spectral energy density of the random field that minimizes pair interactions at constant electromagnetic energy density. We conclude that, under rather general circumstances, it is possible to effectively cancel pair interactions within a range of distance. Hence a colloid can be driven to interact exclusively through many-body interactions
Soft Condensed Matter (cond-mat.soft)
Bloch Oscillations and Landau-Zener Transitions in Flat-Band Lattices with Quadratic and Linear Band Touchings
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Chenhaoyue Wang, Carlos J. Garcia-Cervera, Amartya S. Banerjee
Bloch oscillations (BOs) describe the coherent oscillatory motion of electrons in a periodic lattice under a constant external electric field. Deviations from pure harmonic wave packet motion or irregular Bloch oscillations can occur due to Zener tunneling (Landau-Zener Transitions or LZTs), with oscillation frequencies closely tied to interband coupling strengths. Motivated by the interplay between flat-band physics and interband coupling in generating irregular BOs, here we investigate these oscillations in Lieb and Kagome lattices using two complementary approaches: coherent transport simulations and scattering matrix analysis. In the presence of unavoidable band touchings, half-fundamental and fundamental BO frequencies are observed in Lieb and Kagome lattices, respectively – a behavior directly linked to their distinct band structures. When avoided band touchings are introduced, distinct BO frequency responses to coupling parameters in each lattice are observed. Scattering matrix analysis reveals strong coupling and potential LZTs between dispersive bands and the flat band in Kagome lattices, with the quadratic band touching enhancing interband interactions and resulting in BO dynamics that is distinct from systems with linear crossings. In contrast, the Lieb lattice – a three level system – shows independent coupling between the flat band and two dispersive bands, without direct LZTs occurring between the two dispersive bands themselves. Finally, to obtain a unifying perspective on these results, we examine BOs during a strain-induced transition from Kagome to Lieb lattices, and link the evolution of irregular BO frequencies to changes in band connectivity and interband coupling.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
Strain Effects on Electronic Properties of Cobalt-Based Coordination Nanosheets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Kento Nishigomi, Yu Yi, Souren Adhikary, Kazuhito Tsukagoshi, Katsunori Wakabayashi
We theoretically study the strain effects on the electronic properties of
cobalt-based benzenehexathiol (CoBHT) coordination nanosheets using
first-principles calculations. Two distinct crystal structures,
high-density structure (HDS) and low-density structure (LDS), are
explored. Our results reveal that HDS behaves as a metal, while LDS
exhibits semiconducting. Spin-polarized electronic band structures highlight the presence of energy band structures of Kagome lattice, and
the inclusion of spin-orbit coupling (SOC) results in band gap openings
at high-symmetric K points. Furthermore, we construct the tight-binding
model to investigate the topological properties of CoBHT,
demonstrating anomalous Hall conductivity driven by the intrinsic
Berry curvature. The impact of uniaxial
strain on the electronic and magnetic properties of CoBHT is also studied. Strain
induces significant modifications in magnetic moments and density
of states, particularly in the HDS. Anomalous Hall conductivity is
enhanced under hole-doping conditions, suggesting that strain can be
used to tailor the electronic properties of CoBHT for specific
applications. Our findings underscore the potential of CoBHT nanosheets
for use in next-generation electronic, optoelectronic, and catalytic
devices with tunable properties through strain engineering.
Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures
High-spin magnetic ground states of neutral dopant clusters in semiconductors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Rhine Samajdar, Haonan Zhou, R. N. Bhatt
High-spin states hold significant promise for classical and quantum information storage and emerging magnetic memory technologies. Here, we present a systematic framework for engineering such high-spin magnetic states in dopant clusters formed from substitutional impurities in semiconductors. In single-valley materials such as gallium arsenide, impurity states are hydrogenic and exchange interactions generally favor low-spin configurations, except in special geometries. In contrast, multivalley semiconductors exhibit oscillatory form factors in their exchange couplings, enabling the controlled suppression of selected hopping processes and exchange couplings. Exploiting this feature, we demonstrate how carefully arranged impurities in aluminum arsenide, germanium, and silicon can stabilize ground states with a net spin that scale extensively with system size. Within effective mass theory and the tight-binding approximation for hopping, we construct explicit examples ranging from finite clusters to extended lattices and fractal-like tilings. In two dimensions, we identify several favorable dopant geometries supporting a net spin equal to around half of the fully polarized value in the thermodynamic limit, including one which achieves over $ 70%$ polarization. Our results provide a general design principle for harnessing valley degeneracy in semiconductors to construct robust high-spin states and outline a pathway for their experimental realization via precision implantation of dopants.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
19 pages, 9 figures
New Directions in Focused Ion Beam Induced Deposition for the Nanoprinting of Functional 3D Heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
The focused ion beam (FIB) microscope is well established as a high-resolution machining instrument capable of site-selectively removing material down to the nanoscale. Beyond subtractive processing, however, the FIB can also add material using a technique known as focused ion beam induced deposition (FIBID), enabling the direct-write of complex nanostructures. This work explores new directions in three-dimensional nanoprinting with FIBID, harnessing unique features of helium and neon FIBs to fabricate nanoscale heterostructures, including multimaterial architectures and deposits with engineered internal voids. Detailed insight into the chemical and structural composition of these nanostructures is obtained using advanced electron microscopy, revealing buried interfaces and material transformations. Building on these results, the evolution of FIBID into a versatile platform for functional nanomaterials design is discussed, opening pathways toward next-generation nanoscale devices and technologies.
Materials Science (cond-mat.mtrl-sci)
Hierarchically Engineered Titanium Suboxide Films for High-Efficiency Solar Thermal Conversion
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Silpa S, Ann Eliza Joseph, Srinivas G, Harish C Barshilia, Vinayak B Kamble
We report the development of broadband solar absorber coatings based on titanium suboxide composite thin films on aluminium substrates. The films are fabricated via scalable DC magnetron sputtering using a Ti target, followed by post-annealing in a fixed $ O_2$ partial pressure of 0.45 mbar. By tuning deposition time and annealing temperature, a composite phase of $ Ti_2O_3$ and $ TiO_2$ was achieved. The Raman mapping of the films substantiates the distribution and coexistence of the two phases. The optimized sample, deposited for 10 min and annealed at 500 $ ^oC$ , exhibited a superior solar absorptance ($ {\alpha}_s$ = 0.913) and optimally low thermal emittance ($ {\epsilon}_t$ = 0.11). Nevertheless, the 15- and 20-min deposited films also showed a promising absorptance (>0.85) and emittance values (<0.13). Morphological studies revealed island-type nanostructures, leading to enhanced photothermal performance via electric field confinement, which is validated by optical simulations. This work provides a promising route toward efficient, scalable, and cost-effective spectrally selective solar absorbers for solar thermal applications.
Materials Science (cond-mat.mtrl-sci)
In-situ characterisation and data-driven crystal plasticity analysis of short-to-long crack transition in a ductile aluminium alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Abdalrhaman Koko, Bemin Sheen, Caitlin Green, Fionn Dunne
Crack arrest in ductile alloys plays a critical role in damage-tolerant design for aerospace and structural applications, yet the transition from microstructure-sensitive short cracks to load-controlled long cracks remains poorly understood. Here, we present an in-situ, high-resolution experimental study of crack propagation in cold-worked 5052 aluminium alloy using scanning electron microscopy digital image correlation (SEM-DIC), electron backscatter diffraction (EBSD), and novel data-driven crystal plasticity modelling that uses the SEM-DIC and EBSD directly to calculate the stress. The local (elastic) mode I and II stress intensity factors (SIFs) and the (elastic and elastoplastic) energy release rate were extracted from the DIC-measured displacement field and correlated with the crack interaction with microstructural features. We find that the microstructure-sensitive crack grows in a quasi-brittle manner at low energy release rate until reaching a critical energy release rate, where the crack’s process zone becomes large enough to invoke plastic deformation that blunts the crack, marking a transition from elastically driven microstructure-sensitive crack propagation to plasticity-dominated crack arrest. Our findings establish that the short-to-long crack transition is process-zone governed, rather than being length-scale governed.
Materials Science (cond-mat.mtrl-sci)
Anomalous Fraunhofer patterns in Cd$_3$As$_2$ Josephson Junctions
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-07 20:00 EDT
Rak-Hee Kim, Yeongmin Jang, Bob M. Wang, Dong Yu, Yong-Joo Doh
Majorana zero modes (MZMs) in topological superconductors are promising for quantum computing, yet their unambiguous detection remains challenging. We fabricated Josephson junctions (JJs) using Cd$ _3$ As$ _2$ Dirac semimetal nanoribbons with NbTi superconducting electrodes to investigate topological supercurrents through Fraunhofer pattern analysis. The JJs exhibited excellent quality with high transparency ($ \tau$ = 0.77) and large induced superconducting gap ($ \Delta$ = 1.10 meV), confirmed by multiple Andreev reflection features. While node lifting at the third minimum of the Fraunhofer pattern was observed as a predicted signature of 4{$ \pi$ }-periodic topological supercurrents, our theoretical analysis demonstrates that asymmetric supercurrent distributions can reproduce this behavior without invoking MZMs. These findings reveal that anomalous Fraunhofer patterns alone cannot reliably confirm topological superconductivity, necessitating complementary experimental approaches for conclusive Majorana detection
Superconductivity (cond-mat.supr-con)
14 pages, 4 figures
Electro-optic effects in some sliding ferroelectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Xueqing Wan, Zhenlong Zhang, Charles Paillard, Jinyang Ni, Lei Zhang, Zhijun Jiang, Laurent Bellaiche
Sliding ferroelectrics, which exhibit out-of-plane polarization arising from specific stacking rather than conventional ionic displacements, are new types of ferroelectrics whose underdeveloped physics needs to be explored. Here, we investigate for the first time the electro-optic (EO) response of these materials using first-principles calculations, focusing on ZrI$ _{2}$ as a prototype. We reveal that, contrary to conventional ferroelectrics, the EO effect in ZrI$ _{2}$ is dominated by its electronic contribution rather than the ionic one, which promises faster EO responses. Furthermore, both biaxial and uniaxial strains significantly enhance this response, and a novel, universal-like linear relationship between the band gap and such response is discovered. We also report a large elasto-optic coefficient that is independent of biaxial strain. Similar large linear EO coefficients and properties are found in other sliding ferroelectrics, including different zirconium dihalides, as well as BN and BP bilayers. These findings highlight sliding ferroelectrics as highly promising candidates for ultrafast nonlinear optical devices and reveal novel EO mechanisms.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Insulating transport in anisotropic metals: breakdown of Drude transport and the puzzling $c$-axis resistivity of Sr$_2$RuO$_4$ and other layered oxides
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Sophie Beck, Matthew Shammami, Lorenzo Van Muñoz, Jason Kaye, Antoine Georges, Jernej Mravlje
We reveal a mechanism that may explain the non-metallic out-of-plane resistivity in layered metals. By carefully examining how the Drude-Boltzmann expression for the $ c$ -axis conductivity emerges out of the Kubo formula, we find, besides the standard metallic term proportional to the carrier lifetime $ \tau$ , a non-Drude contribution proportional to $ 1/\tau$ . The Drude behavior breaks down when $ 1/\tau > 2 \eta^\ast$ , the crossover value $ \eta^\ast$ being small (and hence observable) when the $ c$ -axis velocities vary rapidly with the distance from the Fermi surface. We consider the Hund metal Sr$ _2$ RuO$ _4$ as a test case, which we study within a realistic dynamical mean-field theory approach. The non-Drude behavior observed experimentally in $ c$ -axis transport is reproduced and explained by our considerations, showing that earlier invoked extrinsic mechanisms that involve either impurities or phonons are unnecessary. We point out that the small value of $ \eta^\ast$ is due to a peculiar accidental cancellation due to destructive interference characteristic of body-centered tetragonal lattices.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
The magnon spectra of g-type altermagnet bulk CrSb
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
We present a calculation of the magnon spectra and chiral lifetimes of altermagnons in bulk CrSb using the many-body perturbation theory. The spin-split band structure is evident in the magnon spectra. Altermagnons attain an energy of 275 meV at the K point of the Brillouin zone. Due to large spin splitting at a specific $ {\bf q}$ point along the A - M direction, lifetime differences of chiral altermagnons reach approximately 20 fs.
Materials Science (cond-mat.mtrl-sci)
Roton-mediated soliton bound states in binary dipolar condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-10-07 20:00 EDT
We investigate the formation of bound states between dark-antidark solitary waves in two-component dipolar Bose-Einstein condensates. The excitation spectrum contains density and spin branches, and a rotonic feature of the spin branch enables long-range soliton interactions, giving rise to multiple bound states for a single pair, each with a distinct separation. We show that these bound states originate from periodic modulations of the inter-soliton potential, while individual solitons are surrounded by spatial spin-density oscillations. Both features provide direct signatures of the spin roton. Collisions between unbound solitons probe this potential, with dipolar interactions enforcing universal bouncing at low velocities, independent of soliton sign, whereas nondipolar solitons may either transmit or bounce. This distinct behavior offers a realistic path to confirming spin rotons experimentally.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS)
8 pages, 5 figures
Observation of a Novel CDW Superstructure in Monolayer 1T-$VS_{2}$ at Room Temperature and its Evolution in Multilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Samanta Pal, Kaustuv Chatterjee, A. K. Raychaudhuri, Prabir Pal
Spontaneous formation of charge density wave (CDW) superstructures in monolayers (MLs) of a two-dimensional (2D) crystal lattice is fundamental in understanding its complex quantum states. We report a successful top-down liquid phase exfoliation and stamp transfer process (LPESTP) to create ML VS\textsubscript{2}, undergoing a CDW transition at room temperature. Using high-resolution transmission electron microscopy (HRTEM) and electron diffraction (ED), we observed the coexistence of 1T and 2H polymorphic phases in VS\textsubscript{2} at room temperature, and only the 1T phase undergoes CDW transition. We discovered a novel incommensurate CDW superstructure ($ \sqrt{7} \times \sqrt{7}$ ) R19.1\textsuperscript{o} in ML 1T-VS\textsubscript{2}. With an increase in the number of layers, the CDW order changes to a commensurate ($ 2 \times 2$ ) superstructure. Using angle-dependent photoelectron spectroscopy, we have shown that vanadium atoms self-intercalate as V\textsuperscript{3+} ions in multilayer VS\textsubscript{2} and are responsible for the evolution of the CDW superstructure from the incommensurate $ \sqrt{7} \times \sqrt{7}$ ) R 19.1\textsuperscript{o} to the commensurate ($ 2\times2$ ) order. We also report the observation of novel Moiré superlattices in twisted bilayer 1T-VS\textsubscript{2} flakes with trapped CDW superstructure of the monolayer. Our findings provide an important platform for understanding the evolution of CDW superstructures in 1T-VS\textsubscript{2} with thickness and V self-intercalation.
Materials Science (cond-mat.mtrl-sci)
41 pages, 13 Figures
Hybrid MBE Route to Adsorption-Controlled Growth of BaTiO3 Membranes with Robust Polarization Switching
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
S. Choo, S. Varshney, J. Shah, A. K. Manjeshwar, D. K. Lee, K. A. Mkhoyan, R. D. James, B. Jalan
Freestanding ferroelectric membranes are promising for flexible electronics, nonvolatile memory, photonics, and spintronics, but their synthesis is challenged by the need for reproducibility with precise stoichiometric control. Here, we demonstrate the adsorption-controlled growth of single-crystalline, epitaxial BaTiO3 films by hybrid molecular beam epitaxy (MBE) on a binary oxide sacrificial layer. Using a simple water-droplet lift-off method, we obtained submillimeter- to millimeter-sized membranes that retained crystallinity, as confirmed by high-resolution X-ray diffraction, and exhibited robust tetragonal symmetry by Raman spectroscopy. Impedance spectroscopy confirmed a high dielectric constant of 1340, reflecting the robust dielectric response of the membranes. Ferroelectric functionality was revealed by piezoresponse force microscopy (PFM) and further verified by polarization-electric field (P-E) loop measurements with Positive-Up-Negative-Down (PUND). The P-E loops exhibited a remnant polarization of 5 microC cm-2 and a coercive field of 63 kV cm-1. These results were interpreted in relation to c- and a-domain configurations. These results establish hybrid MBE as a generalizable route for producing stoichiometry-controlled ferroelectric membranes, enabling their integration into next-generation flexible and multifunctional quantum oxide devices.
Materials Science (cond-mat.mtrl-sci)
22 pages 4 figures
Quantized Piezospintronic Effect in Moiré Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Mario Castro, Benjamín Mancilla, Fabian Wolff, Alvaro S. Nunez
This paper presents a novel approach for generating and controlling spin currents in an antiferromagnetic twisted honeycomb bilayer in response to an elastic deformation. Utilizing a continuum model, closely based upon the seminal Bistritzer-MacDonald model, that captures the essential physics of low-energy moiré bands, we calculate the spin current response to the deformation in terms of the familiar Berry phase formalism. The resulting moiré superlattice potential modulates the electronic band structure, leading to emergent topological phases and novel transport properties such as quantized piezo responses both for spin and charge transport. This approach allows us to tune the system across different topological regimes and to explore the piezo-spintronic responses as a function of the band topology. When inversion symmetry is broken either by a sublattice potential $ V$ , alignment with an hBN substrate, uniaxial strain, or structural asymmetry present in the moiré superlattice, the system acquires a finite Berry curvature that is opposite in the $ K$ and $ K’$ valleys (protected by valley time reversal symmetry). In contrast, for strain, the valley-contrasting nature of the pseudo-gauge field ensures that the quantized response is robust and proportional to the sum of the valley Chern numbers. These notable physical properties make these systems promising candidates for groundbreaking spintronic and valleytronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Lattice Translation Modulated Symmetries and TFTs
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Modulated symmetries are internal symmetries that are not invariant under spacetime symmetry actions. We propose a general way to describe the lattice translation modulated symmetries in 1+1D, including the non-invertible ones, via the tensor network language. We demonstrate that the modulations can be described by some autoequivalences of the categories. Although the topological behaviors are broken because of the presence of modulations, we can still construct the modulated version of the symmetry TFT bulks by inserting a series of domain walls described by invertible bimodule categories. This structure not only recovers some known results on invertible modulated symmetries but also provides a general framework to tackle modulated symmetries in a more general setting.
Strongly Correlated Electrons (cond-mat.str-el)
24 pages, 6 figures
Adsorption-induced surface magnetism
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Miloš Baljozović, Shiladitya Karmakar, André L. Fernandes Cauduro, Mothuku Shyam Sundar, Marco Lozano, Manish Kumar, Diego Soler Polo, Andreas K. Schmid, Ashutosh V. Bedekar, Pavel Jelinek, Karl-Heinz Ernst
We report the emergence of adsorption-induced magnetism from heterohelicene molecules on a non-magnetic Cu(100) surface. Spin-polarized low-energy electron microscopy (SP-LEEM) measurements reveal spin-dependent electron reflectivity for enantiopure 7,12,17-trioxa[11]helicene (TO[11]H) monolayers, indicating the formation of a spin-polarized state localized in the topmost copper layer. Control experiments on clean Cu(100) and TO[11]H on highly oriented pyrolytic graphite show no such effect, excluding artifacts and chirality-induced spin selectivity as origins. Spin-polarized density functional theory calculations with hybrid functionals attribute the magnetism to strong chemisorption, which induces hybridization between the molecular HOMO and copper s- and d-states, driving asymmetric spin-polarized charge redistribution at the interface. An extended Newns-Anderson-Grimley model incorporating on-site Coulomb repulsion in Cu d-orbitals reproduces the emergence of interfacial spin polarization above a threshold interaction strength, highlighting the key roles of hybridization parameters and Coulomb correlation. These findings reveal a mechanism for inducing magnetism at molecule-metal interfaces without inherently magnetic components, offering new avenues for engineering spin-polarized states in organic-inorganic hybrid systems.
Materials Science (cond-mat.mtrl-sci)
Optimal Computation from Fluctuation Responses
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-07 20:00 EDT
Jinghao Lyu, Kyle J. Ray, James P. Crutchfield
The energy cost of computation has emerged as a central challenge at the intersection of physics and computer science. Recent advances in statistical physics – particularly in stochastic thermodynamics – enable precise characterizations of work, heat, and entropy production in information-processing systems driven far from equilibrium by time-dependent control protocols. A key open question is then how to design protocols that minimize thermodynamic cost while ensur- ing correct outcomes. To this end, we develop a unified framework to identify optimal protocols using fluctuation response relations (FRR) and machine learning. Unlike previous approaches that optimize either distributions or protocols separately, our method unifies both using FRR-derived gradients. Moreover, our method is based primarily on iteratively learning from sampled noisy trajectories, which is generally much easier than solving for the optimal protocol directly from a set of governing equations. We apply the framework to canonical examples – bit erasure in a double-well potential and translating harmonic traps – demonstrating how to construct loss functions that trade-off energy cost against task error. The framework extends trivially to underdamped systems, and we show this by optimizing a bit-flip in an underdamped system. In all computations we test, the framework achieves the theoretically optimal protocol or achieves work costs comparable to relevant finite time bounds. In short, the results provide principled strategies for designing thermodynamically efficient protocols in physical information-processing systems. Applications range from quantum gates robust under noise to energy-efficient control of chemical and synthetic biological networks.
Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG)
10 pages, 6 figures; this https URL
Higher-form entanglement asymmetry and topological order
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Amanda Gatto Lamas, Jacopo Gliozzi, Taylor L. Hughes
We extend a recently defined measure of symmetry breaking, the entanglement asymmetry, to higher-form symmetries. In particular, we focus on Abelian topological order in two dimensions, which spontaneously breaks a 1-form symmetry. Using the toric code as a primary example, we compute the entanglement asymmetry and compare it to the topological entanglement entropy. We find that while the two quantities are not strictly equivalent, both are sub-leading corrections to the area law and can serve as order parameters for the topological phase. We generalize our results to non-chiral Abelian topological order and express the maximal entanglement asymmetry in terms of the quantum dimension. Finally, we discuss how the scaling of entanglement asymmetry correctly detects topological order in the deformed toric code, where 1-form symmetry breaking persists even in a trivial phase.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
7 pages, 3 figures
Finding the temperature window for atomic layer deposition of ruthenium metal via efficient phonon calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Alexandr Fonari, Simon D. Elliott, Casey N. Brock, Yan Li, Jacob Gavartin, Mathew D. Halls
We investigate the use of first principles thermodynamics based on periodic density functional theory (DFT) to examine the gas-surface chemistry of an oxidized ruthenium surface reacting with hydrogen gas. This reaction system features in the growth of ultrathin Ru films by atomic layer deposition (ALD). We reproduce and rationalize the experimental observation that ALD of the metal from RuO4 and H2 occurs only in a narrow temperature window above 100°C, and this validates the approach. Specifically, the temperature-dependent reaction free energies are computed for the competing potential reactions of the H2 reagent, and show that surface oxide is reduced to water, which is predicted to desorb thermally above 113°C, exposing bare Ru that can further react to surface hydride, and hence deposit Ru metal. The saturating coverages give a predicted growth rate of 0.7 Å/cycle of Ru. At lower temperatures, free energies indicate that water is retained at the surface and reacts with the RuO4 precursor to form an oxide film, also in agreement with experiment. The temperature dependence is obtained with the required accuracy by computing Gibbs free energy corrections from phonon calculations within the harmonic approximation. Surface phonons are computed rapidly and efficiently by parallelization on a cloud architecture within the Schrödinger Materials Science Suite. We also show that rotational and translational entropy of gases dominate the free energies, permitting an alternative approach without phonon calculations, which would be suitable for rapid pre-screening of gas-surface chemistries.
Materials Science (cond-mat.mtrl-sci)
A van der Waals material exhibiting room temperature broken inversion symmetry with ferroelectricity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Fabia F. Athena, Cooper A. Voigt, Mengkun Tian, Anjan Goswami, Emily Toph, Moses Nnaji, Fanuel Mammo, Brent K. Wagner, Sungho Jeon, Wenshan Cai, Eric M. Vogel
Since the initial synthesis of van der Waals two-dimensional indium selenide was first documented in 1957, five distinct polymorphs and their corresponding polytypes have been identified. In this study, we report a unique phase of indium selenide via Scanning Transmission Electron Microscopy (STEM) analysis in the synthesized large-area films – which we have named the $ \beta^\text{p}$ phase. The quintuple layers of the $ \beta^\text{p}$ phase, characterized by a unique zigzag atomic configuration with unequal indium-selenium bond lengths from the middle selenium atom, are distinct from any other previously reported phase of indium selenide. Cross-sectional STEM analysis has revealed that the $ \beta^\text{p}$ layers exhibit intralayer shifting. We found that indium selenide films with $ \beta^\text{p}$ layers display electric-field-induced switchable polarization characteristic of ferroelectric materials, suggesting the breaking of the inversion symmetry. Experimental observations of nonlinear optical phenomena – Second Harmonic Generation (SHG) responses further support this conclusion. This study reports a $ \beta^\text{p}$ phase of indium selenide showing ferroelectricity over large areas at room temperature in a low-dimensional limit.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Coupling a $^{73}$Ge nuclear spin to an electrostatically defined quantum dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Paul Steinacker, Gauri Goenka, Rocky Yue Su, Tuomo Tanttu, Wee Han Lim, Santiago Serrano, Tim Botzem, Jesus D. Cifuentes, Shao Qi Lim, Jeffrey C. McCallum, Brett C. Johnson, Fay E. Hudson, Kok Wai Chan, Christopher C. Escott, Andre Saraiva, Chih Hwan Yang, Vincent Mourik, Andrea Morello, Andrew S. Dzurak, Arne Laucht
Single nuclear spins in silicon are a promising resource for quantum technologies due to their long coherence times and excellent control fidelities. Qubits and qudits have been encoded on donor nuclei, with successful demonstrations of Bell states and quantum memories on the spin-1/2 $ ^{31}$ P and cat-qubits on the spin-7/2 $ ^{123}$ Sb nuclei. Isoelectronic nuclear spins coupled to gate-defined quantum dots, such as the naturally occurring $ ^{29}$ Si isotope, possess no additional charge and allow for the coupled electron to be shuttled without destroying the nuclear spin coherence. Here, we demonstrate the coupling and readout of a spin-9/2 $ ^{73}$ Ge nuclear spin to a gate-defined quantum dot in SiMOS. The $ ^{73}$ Ge nucleus was implanted by isotope-selective ion-implantation. We observe the hyperfine interaction (HFI) to the coupled quantum dot electron and are able to tune it from 180 kHz to 350 kHz, through the voltages applied to the lateral gate electrodes. This work lays the foundation for future spin control experiments on the spin-9/2 qudit as well as more advanced experiments such as entanglement distribution between distant nuclear spins or repeated weak measurements.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
7 pages, 3 figures
Fractional quantum Hall state at $ν= 1/2$ with energy gap up to 6 K, and possible transition from one- to two-component state
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Siddharth Kumar Singh, Chengyu Wang, Adbhut Gupta, Kirk W. Baldwin, Loren N. Pfeiffer, Mansour Shayegan
The fractional quantum Hall state (FQHS) observed in the lowest Landau level at filling factor $ \nu=1/2$ in wide quantum wells has been enigmatic for decades because the two-dimensional electron system (2DES) has a bilayer charge distribution but with significant interlayer tunneling. Of particular interest is whether the 1/2 FQHS in this system has a one-component (1C) or two-component (2C) origin; these are typically identified as the Pfaffian (non-Abelian) or the $ \Psi_{331}$ (Abelian) FQHSs, respectively. We report here our experimental study of the evolution of the correlated states of an ultrahigh-quality 2DES confined to a 72.5-nm-wide GaAs quantum well. At the lowest densities, the 2DES displays only odd-denominator FQHSs, and the ground state at $ \nu = 1/2$ is a composite fermion Fermi sea. As the density is increased, a FQHS emerges at $ \nu = 1/2$ , and becomes very strong. In a finite density range where the 1/2 FQHS is strongest, we also observe its daughter FQHSs at $ \nu = 8/17$ and 7/13, consistent with the theoretically expected daughter states of a Pfaffian 1/2 FQHS. At the highest densities, the 2DES becomes 2C, signaled by the emergence of a bilayer Wigner crystal state and the transitions of FQHSs flanking $ \nu=1/2$ . The 1/2 FQHS remains robust near this transition and, notably, its charge transport energy gap exhibits an \textit{upward} cusp with a maximum value of about 6 K on the 1C side of the transition; this is the largest gap reported for any even-denominator FQHS. Our observation of the transition of the 2DES ground states near $ \nu=1/2$ to 2C states at high densities, and our measurements of the robustness of the 1/2 FQHS against charge distribution asymmetry, suggest that the 1/2 FQHS also makes a transition from 1C to 2C. Such a transition from a non-Abelian to Abelian state can open avenues for topological quantum information and quantum criticality.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Accepted for publication in Phys. Rev. Lett., 8+13 pages, 3+7 figures
Effective linear response in non-equilibrium anyonic systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Gu Zhang, Igor Gornyi, Yuval Gefen
Linear response theory serves as a fundamental tool in the study of quantum transport, extensively employed to elucidate fundamental mechanisms related to the nature of the particles involved and the underlying symmetries. This framework is, however, limited to equilibrium or near-equilibrium conditions. Here, we develop an effective linear response theory designed to describe charge and thermal quantum transport, where the reference far-from-equilibrium stationary state comprises anyons forming a dilute beam. We apply our theory to study tunnel-coupled anyonic beams in collider geometries, enabling braiding, collisions, and tunneling of anyons at the central collider. Our linear-response transport coefficients directly reflect the fractional charge and statistics of the anyons involved, avoiding the need to measure higher-order current correlations. Moreover, the emergence of finite thermoelectric (Peltier and Seebeck) coefficients signifies the presence of real anyon collisions (as opposed to virtual braiding in the time domain), intimately associated with a broken particle-hole symmetry, specific to anyonic gases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
44 pages, 10 figures
Atomistic Machine Learning with Cartesian Natural Tensors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Qun Chen, A. S. L. Subrahmanyam Pattamatta, David J. Srolovitz, Mingjian Wen
Atomistic machine learning (ML) is a transformative tool for accurate and efficient investigation of material behavior at the atomic scale. While such models have been constructed within Cartesian space to harness geometric information and preserve intuitive physical representations, they face inherent challenges - primarily due to the lack of a systematic symmetry-preserving framework for representing arbitrary physical tensors. We address these challenges by proposing Cartesian Natural Tensor Networks (CarNet) as a general framework for atomistic ML. We first develop the theory of irreducible representations using Cartesian natural tensors (their creation, operation, as well as the decomposition and reconstruction of physical tensors such as the elastic constant tensor). Leveraging this machinery, we design an equivariant Cartesian model and demonstrate its exceptional performance across diverse atomistic ML tasks. CarNet enables the development of highly accurate and reliable interatomic potentials for both materials and molecular systems. Furthermore, structure-property relationships can be readily constructed for tensorial quantities ranging from simple properties like the dipole moment to arbitrary high-rank tensors with complex symmetries such as the elastic constant tensor – capabilities that were previously inaccessible. This work removes theoretical barriers and unleashes the power of Cartesian approaches for advanced atomistic ML in the understanding and design of new materials.
Materials Science (cond-mat.mtrl-sci), Mathematical Physics (math-ph)
Operator dependence and robustness of spacetime-localized response in a quantum critical spin chain
New Submission | Other Condensed Matter (cond-mat.other) | 2025-10-07 20:00 EDT
Daichi Imagawa, Keiju Murata, Daisuke Yamamoto
We investigate the phenomenon of spacetime-localized response in a quantum critical spin system, with particular attention to how it depends on the spatial profile and operator content of the applied perturbation, as well as its robustness against increase of amplitude and temporal discretization. Motivated by recent theoretical proposals linking such response patterns to the anti-de Sitter/conformal field theory correspondence, we numerically analyze the real-time dynamics of the one-dimensional transverse-field Ising model at criticality using the time-evolving block decimation algorithm. We find that sharply localized and periodically recurring responses emerge only for specific types of perturbations, namely those that correspond to local density fields in the continuum limit. In contrast, perturbations involving other spin components produce conventional propagating excitations without localization. Furthermore, we demonstrate that the response remains qualitatively robust when the time-dependent perturbation is approximated by a piecewise-linear function, highlighting the practical relevance of our findings for quantum simulation platforms with limited temporal resolution. Our results clarify the operator dependence of emergent bulk-like dynamics in critical spin chains and offer guidance for probing holographic physics in experimental settings.
Other Condensed Matter (cond-mat.other), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
12 pages, 9 figures
Dynamics of the Kac Ring Model with switching scatterers
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-07 20:00 EDT
Leonid A. Bunimovich, Emilio N. M. Cirillo, Matteo Colangeli, Lamberto Rondoni
We introduce a generalized version of the Kac ring model in which particles are of two types, black and white. Black particles modify the environment through which all particles move, thereby inducing indirect and potentially long-range interactions among them. Unlike the inert scatterers of Kac’s original model, the scatterers in our setting possess internal states that change upon interaction with black particles and can be interpreted as energy levels of the environment. This makes the model self-consistent, as it incorporates a form of particle interactions, mediated by the environment, that drives the system toward some kind of stationary state. Although indirect and long-range interactions do not necessarily promote thermodynamic states, interactions are necessary for energy to be shared among the elementary constituents of matter, enabling the establishment of equipartition, which is a prerequisite for defining temperature. Therefore, our model is one step forward in this direction, elucidating the role of interactions and energy exchange. We prove that any initial state of the system converges to a time periodic state (i.e. a phase space orbit) and describe basins of attraction for some of such asymptotic periodic states.
Statistical Mechanics (cond-mat.stat-mech), Dynamical Systems (math.DS)
Strong coupling phases of conserved growth models are crumpled
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-07 20:00 EDT
We show that stochastically driven nonequilibrium conserved growth models admit strong coupling phases for sufficiently strong nonlocal chemical potentials underlying the dynamics. The models exhibit generic roughening transitions between perturbatively accessible weak coupling phases satisfying an exact relation between the dynamic $ z$ and roughness $ \chi$ exponents in all dimensions $ d$ and strong coupling phases. In dimensions below the critical dimension, the latter phases are unstable and argued to be crumpled, and thus distinct from the well-known strong coupling rough phase of the Kardar-Parisi-Zhang equation in dimensions $ d\geq 2$ . At the critical dimension, conventional spatio-temporal scaling in the weak coupling phase is logarithmically modulated and are exactly obtained. These results obtained by employing a combination of nonperturbative arguments and perturbative theories, corroborated by numerical results.
Statistical Mechanics (cond-mat.stat-mech)
preliminary version
Direct observation of band structure modifications from monolayer WSe2 to Janus WSSe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Masato Sakano, Shunsuke Akatsuka, Takato Yamamoto, Tianyishan Sun, Dingkun Bi, Hiroto Ogura, Naoya Yamaguchi, Fumiyuki Ishii, Natsuki Mitsuishi, Kenji Watanabe, Takashi Taniguchi, Miho Kitamura, Koji Horiba, Kenichi Ozawa, Katsuaki Sugawara, Seigo Souma, Takafumi Sato, Yuta Seo, Satoru Masubuchi, Tomoki Machida, Toshiaki Kato, Kyoko Ishizaka
Janus monolayer transition metal dichalcogenides (TMDs), created by post-growth substitution of the top chalcogen layer, represent a new direction for engineering 2D crystal properties. However, their rapid ambient degradation and the difficulty of obtaining large-area monolayer samples have limited the available experimental probes, leaving their detailed electronic structure near the Fermi level largely unexplored. In this work, by performing micro-focused angle-resolved photoemission spectroscopy ({\mu}-ARPES) on an identical sample transformed from monolayer WSe2 to Janus WSSe via a H2 plasma-assisted chalcogen-exchange method, we reveal the evolution of its electronic band structure. We observe ARPES signature consistent with the Rashba-type spin splitting due to broken horizontal mirror symmetry, and a significant upward shift of the highest valence band at the {\Gamma}-point by approximately 160 meV. These direct observations clarify the key electronic modifications that govern the material’s properties and provide a pathway for band engineering in Janus TMDs.
Materials Science (cond-mat.mtrl-sci)
16 pages, 4 figures
Quantum Linear Magnetoresistance: A Modern Perspective
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Magnetoresistance is a powerful probe for characterizing the intrinsic physics embedded in materials. Among its various manifestations, linear magnetoresistance has a long history and continues attracting research interest. In contemporary studies, a clear understanding of the magnetoresistance character of quantum origin is more crucial than ever for the study of emerging materials. In this perspective, we examine the linear magnetoresistance of quantum mechanism, from its theoretical basis to experimental studies, and discuss open questions and promising future research directions in this field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Ground state and excitations of quasiperiodic 1D narrow-band moiré systems: a mean field approach
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Nicolau Sobrosa, Miguel Gonçalves, Bruno Amorim, Eduardo V. Castro, Pedro Ribeiro
We demonstrate that a mean field approximation can be confidently employed in quasiperiodic moiré systems to treat interactions and quasiperiodicity on equal footing. We obtain the mean field phase diagram for an illustrative one-dimensional moiré system that exhibits narrow bands and a regime with non-interacting multifractal critical states. By systematically comparing our findings with existing exact results, we identify the regimes where the mean field approximation provides an accurate description. Interestingly, in the critical regime, we obtain a quasifractal charge density wave, consistent with the exact results. To complement this study, we employ a real-space implementation of the time-dependent Hartree-Fock, enabling the computation of the excitation spectrum and response functions at the RPA level. These findings indicate that a mean field approximation to treat systems hosting multifractal critical states, as found in two-dimensional quasiperiodic moiré systems, is an appropriate methodology.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)
12 pages, 10 figures
Right-eigenstate-based approach to non-Hermitian superfluidity with two-body loss
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-10-07 20:00 EDT
Xuezhu Liu, Ming Lu, Haiwen Liu
We theoretically explore a non-Hermitian superfluid model with complex-valued interaction, inspired by two-body loss stemming from inelastic scattering observed in ultracold atomic experiments. Utilizing both the right-eigenstate-based mean-field theory and its biorthogonal counterpart, we study the properties of the system. Notably, the right-eigenstate-based framework produces smooth and continuous solutions, in stark contrast to the absence of nontrivial solutions and the abrupt discontinuities observed in the biorthogonal-eigenstate-based framework under moderate dissipation. In addition, the lower condensation energy obtained in the former framework suggests its superior suitability for describing this system. Furthermore, we explore the impact of backscattering, a crucial factor in realistic systems. Our analysis reveals that, facilitated by two-body loss, even moderate backscattering destabilizes the superfluid state. Sufficiently strong backscattering completely destroys it, highlighting a key mechanism for the fragility of this non-Hermitian quantum phase.
Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con)
7 pages, 4 figures
More bridging ligands activate direct exchange: the case of anisotropic Kitaev effective magnetic interactions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Pritam Bhattacharyya, Nikolay A. Bogdanov, Liviu Hozoi
A magnet is a collection of magnetic moments. How those interact is determined by what lies in between. In transition-metal and rare-earth magnetic compounds, the configuration of the ligands around each magnetic center and the connectivity of the ligand cages are therefore pivotal – for example, the mutual interaction of magnetic species connected through one single ligand is qualitatively different from the case of two bridging anions. Two bridging ligands are encountered in Kitaev magnets. The latter represent one of the revelations of the 21st century in magnetism research: they feature highly anisotropic intersite couplings with seemingly counterintuitive directional dependence for adjacent pairs of magnetic sites and unique quantum spin-liquid ground states that can be described analytically. Current scenarios for the occurrence of pair-dependent magnetic interactions as proposed by Kitaev rely on $ indirect$ exchange mechanisms based on intersite electron hopping. Analyzing the wavefunctions of Kitaev magnetic bonds at both single- and multi-configuration levels, we find however that $ direct$ , Coulomb exchange may be at least as important, in 5$ d$ and 4$ d$ $ t_{2g}^5$ , 3$ d$ $ t_{2g}^5e_g^2$ , and even rare-earth 4$ f^1$ Kitaev-Heisenberg magnets. Our study provides concept clarification in Kitaev magnetism research and the essential reference points for reliable computational investigation of how novel magnetic ground states can be engineered in Kitaev, Kitaev-Heisenberg, and Heisenberg edge-sharing systems.
Strongly Correlated Electrons (cond-mat.str-el)
Dynamic breaking of axial symmetry of acoustic waves in crystals as the origin of nonlinear inelasticity and chaos: Analytical model and MD simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
A Chain of Springs and Masses (CSM) model is used in the interpretation of molecular dynamics (MD) simulations of movement of atoms in FCC crystals, oriented like during typical simulations performed in studies of the dynamics of line dislocations. The proposed description is inspired by and supported by MD simulations. We find out that a force that is perpendicular to the direction of the applied external shear pressure and in the direction of line dislocations occurs within the bulk of crystal volume. The force is of a dynamic origin, and it has not been analyzed so far. It is proportional to the square of the applied pressure; It causes breaking of axial symmetry for propagation of transverse acoustic waves. It leads to a non-linear and non-elastic response of crystals and to chaotic patterns in motion of atoms. We provide an analytical derivation of an effective atomistic potential for interaction between atoms and propose an analytical model of their dynamics. The model predicts some effects that may have been overlooked in experiments and are inconsistent with the static theory of elasticity of crystals.
Materials Science (cond-mat.mtrl-sci)
Longitudinal transport spin polarization of spin degenerate antiferromagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Meng Zhu, Jianting Dong, Xinlu Li, Jiahao Shentu, Yizhuo Song, Evgeny Y. Tsymbal, Jia Zhang
A vital goal in spintronics is the efficient electrical generation of spin currents, a pursuit that has recently focused on using antiferromagnets (AFMs) as spin current sources. It has been demonstrated that antiferromagnets with broken PT symmetry (parity + time reversal) can efficiently generate longitudinal and transverse spin currents. At the same time, it has been generally thought that antiferromagnets with PT symmetry (PT-AFMs) forbid the longitudinal spin polarization due to their spin-degenerate band structure. Here, in contrast to this common expectation, we show, using theoretical analysis based on magnetic point group symmetry, that most PT-AFMs can generate longitudinal spin currents due to spin-orbit coupling. Using density-functional theory, we calculate the longitudinal spin conductivity of representative PT-AFMs, L10-MnPt and Mn2Au, and show that its magnitude is comparable to that of their PT-broken counterparts. Our symmetry-enabled classification of antiferromagnets and theoretical results for the longitudinal spin conductivity in representative PT-AFMs expands our understanding of spin transport and shows the possibility of robust spin-current generation in a broad range of spin-degenerate antiferromagnets.
Materials Science (cond-mat.mtrl-sci)
Variation Monte Carlo Study on the bilayer $t-J_{\parallel}-J_{\perp}$ model for La$_3$Ni$_2$O$_7$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-07 20:00 EDT
Zeyu Chen, Yu-Bo Liu, Fan Yang
The discovery of high-temperature superconductivity (HTSC) in La$ 3$ Ni$ 2$ O$ 7$ has aroused significant interest in exploring the pairing mechanism. Previous studies have proposed an effective d$ {x^2-y^2}$ -orbital bilayer $ t-J{\parallel}-J{\perp}$ model, in which the electrons of the d$ {x^2-y^2}$ orbital are charge carriers, which are subject to the intralayer antiferromagnetic (AFM) superexchange $ J{\parallel}$ and the large interlayer AFM superexchange $ J{\perp}\approx 2J{\parallel}$ , with the latter transferred from the nearly half-filled and hence localized $ d_{z^2}$ orbital through the strong Hund’s rule coupling. Here we study this model by the variational Monte Carlo (VMC) simulation and find a dominant interlayer s-wave pairing, in which the SC order parameters have a drastic improvement compared with those of the mean field (MF) type of theories. In real materials, the Hund’s coupling is finite, leading to reduced $ J_{\perp}$ , dictating that the MF-type theories have difficulty explaining the HTSC. However, our VMC calculations find that even for effective $ J_{\perp}$ as weak as $ J_{\perp}=J_{\parallel}$ , the interlayer pairing is still considerably large and can be compared with the $ T_c$ observed in experiments, which is very weak in MF-type theories. This result indicates the important role of the Gutzwiller projection in improving the $ T_c$ , which is ignored in the MF-type theories. In addition, our results show that suppressed interlayer hopping can promote interlayer pairing, which is consistent with the fact that the interlayer hopping of the d$ _{x^2-y^2}$ orbital in La$ _3$ Ni$ _2$ O$ _7$ is very weak. Our research offers a new perspective for understanding the pairing mechanism of bilayer nickelates and provides a reference for recent ultra-cold atom experiments in mixed-dimensional systems.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 10 figures
Interplay of order and disorder in two-dimensional critical systems with mixed boundary conditions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-07 20:00 EDT
In spin systems such as the Ising model, the local order and disorder can be characterized by the order-parameter and energy density profiles $ \langle \sigma ({\bf r}_1) \rangle$ and $ \langle \epsilon ({\bf r}_2) \rangle$ , respectively. Does increasing the order at $ {\bf r}_1$ always decrease the disorder at $ {\bf r}_2$ ? Does increasing the disorder at $ {\bf r}_2$ always decrease the order at $ {\bf r}_1$ ? The answer to these questions is contained in the cumulant response function $ \langle\sigma ({\bf r}_1) , \epsilon ({\bf r}_2) \rangle^{(\rm cum)}$ . This correlation function vanishes in the unbounded bulk but not in systems with fixed-spin boundary conditions. Using the universal operator-product expansion of $ \sigma ({\bf r}_1) , \epsilon ({\bf r}_2)$ and exact results for the Ising model, we analyze $ \langle\sigma ({\bf r}_1) , \epsilon ({\bf r}_2) \rangle^{(\rm cum)}$ in two-dimensional critical systems defined on the $ x-y$ plane with mixed $ +$ and $ -$ boundary conditions. Particularly interesting behavior is found when either of the operators $ \sigma$ or $ \epsilon$ is located on a ``zero line” in the $ x-y$ plane, along which $ \langle\sigma ({\bf r})\rangle$ vanishes. Results for half-plane, triangular, and rectangular geometries are presented.
Statistical Mechanics (cond-mat.stat-mech)
37 pages, 2 figures
Self-induced buckling in hollow microgels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Leah Rank, Emanuela Zaccarelli
Hollow microgels are elastic polymer shells easily realisable in experiments. Recent works have shown the emergence of buckling events in single hollow microgels under the effect of an added osmotic pressure. Here, we perform large-scale simulations to show that these microgels at high enough packing fractions undergo spontaneous symmetry-breaking deformations ranging from single large dents to multiple indentations, even in the absence of any externally applied stress. This buckling phenomenology is thus self-induced, solely driven by interparticle crowding. We construct a phase diagram inspired by vesicle shape theories, mapping local curvature metrics as a function of the reduced volume, to quantify these findings, and we also propose ways to observe the occurrence of buckling in experiments. The present results thus rationalise the deformations occurring in suspensions of micro- and nano-scale elastic shells, offering a synthetic analogue to biological ones, allowing direct control on buckling instabilities for potential applications. Beyond materials design, these insights may also shed light on shape regulation in natural systems such as cells and vesicles, where similar deformations are observed.
Soft Condensed Matter (cond-mat.soft)
33 pages, 8 Figures, International Soft Matter Conference 2025
Optical conductivity and band gap in the double-Weyl candidate SrSi2 at ambient pressure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
L. Z. Maulana, A. A. Tsirlin, E. Uykur, Y. Saito, M. Dressel, M. Imai, A. V. Pronin
We probe the possible double-Weyl state in cubic SrSi2 using optical spectroscopy. The complex optical conductivity was measured in a frequency range from 70 to 22 000 cm-1 at temperatures down to 10 K at ambient pressure. The optical response of SrSi2 can be well separated into the intraband (free carriers) and interband contributions. Additionally, four infrared-active phonons are detected. As follows from the optical spectra, the free-carrier density decreases with decreasing temperature, consistent with an activation behaviour. Experimental interband conductivity juxtaposed with ab initio calculations shows that conventional density-functional theory fails to describe the electronic structure of SrSi2 in the vicinity of the Fermi level. A semi-local exchange-correlation potential allows a much better agreement with the experiment, resulting in the trivial (gapped) band structure of SrSi2. The direct gap estimated from the measurements is approximately 40 meV.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
Classification of Weyl point trajectories in multi-terminal Josephson junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Kento Takemura, Tomohiro Yokoyama
Topological protection is an attractive signature in both fundamental and applied researches because it provides an exotic and robust state. Multi-terminal Josephson junctions have recently been studied extensively owing to the emergence of topologically protected Weyl points without the need for topological materials. In this study, we examine the dynamic properties of Weyl points in multi-terminal Josephson junctions. The junctions are modulated by external parameters, such as electric gate voltage, magnetic flux, bias voltage. The Weyl points are manipulated and draw trajectories accompanied by pair creation and annihilation. The trajectories form both closed loops and open lines. We classify these trajectories using the Chern number and the phase diagram.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
8 figures for main text, 6 figures for Appendix, 16 pages in total
Novel family of near-room-temperature compensated itinerant pyrochlore ferrimagnets, $R{\mathrm{In}}{\mathrm{Co}}_{4}$ ($R=$ Dy-Tm)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
T. Shiotani, T. Waki, Y. Tabata, I. Kézsmárki, H. Nakamura
We successfully synthesized single crystals of a series of C15b Laves phase compounds, $ R{\mathrm{In}}{\mathrm{Co}}{4}$ ($ R=$ Dy-Tm), with Co-pyrochlore and $ R$ -fcc sublattices, and systematically studied their magnetic properties via magnetometry measurements. These itinerant cubic compounds, with Curie temperatures above room temperature, show compensated ferrimagnetism featuring an antiferromagnetic coupling between the two sublattices. From this series, $ {\mathrm{DyInCo}}{4}$ exhibits the highest $ T_{\rm C}$ (= 368 K) and a near-room-temperature compensation point $ T_{\rm cp}$ (= 295 K). $ T_{\rm C}$ does not change drastically with the $ R$ atom, whereas $ T_{\rm cp}$ depends on the de Gennes factor of $ R^{3+}$ . Another magnetization anomaly is observed in all the compounds at low temperatures, which may be indicative of changes in the lattice or magnetic structure. The easy axis the ferrimagnetic moment of $ {\mathrm{DyInCo}}{4}$ , $ {\mathrm{ErInCo}}{4}$ , and $ {\mathrm{TmInCo}}{4}$ is found at $ T =$ 5 K to be along the [001], [111] and [110] directions, respectively. However, the simple easy-axis or easy-plane ferrimagnetic picture cannot be applied to $ {\mathrm{HoInCo}}{4}$ . These observations suggest that the $ R$ sublattice determines magnetic anisotropy and compensation, while the Co sublattice plays a role in strong magnetic ordering. The high Curie temperature, together with the magnetization compensation point near room temperature, renders these itinerant pyrochlore magnets interesting for spintronic applications.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
8 pages, 6 figures, 3 Tables
Mixing of a binary passive particle system using smart active particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Thomas Jacob, Siddhant Mohapatra, Rajalingam A, Sam Mathew, Pallab Sinha Mahapatra
Controlled activity of active entities interacting with a passive environment can generate emergent system-level phenomena, positioning such systems as promising platforms for potential downstream applications in targeted drug delivery, adaptive and reconfigurable materials, microfluidic transport and related fields. The present work aims to realise an optimal mixing of two segregated species of passive particles by introducing a small fraction of active particles (2% by composition) with adaptive and intelligent behaviour, directed by a trained Artificial Neural Network-based agent. While conventional run-and-tumble particles can induce mixing in the system, the smart active particles demonstrate superior performance, achieving faster and more efficient mixing. Interestingly, an optimal mixing strategy doesn’t involve a uniform dispersion of active particles in the domain, but rather limiting their motion to an eccentrically placed zone of activity, inducing a global rotational motion of the passive particles about the system centre. A transition in the directionality of the passive particles’ motion is observed along the radius towards the centre, likening the active particles’ motion to an ellipse-shaped void with a defined surface speed. Situated at the intersection of active matter and machine learning, this work highlights the potential of integrating adaptive learning frameworks into traditional active matter models.
Soft Condensed Matter (cond-mat.soft), Computational Physics (physics.comp-ph)
The Supplementary Information is available on request from the authors
Braids and Beams: Exploring Fractional Statistics with Mesoscopic Anyon Colliders
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Bernd Rosenow, Bertrand I. Halperin
Anyon colliders – quantum Hall devices where dilute quasiparticle beams collide at a quantum point contact – provide an interferometer-free probe of anyonic exchange phases through current cross correlations. Within a non-equilibrium bosonization framework, the normalized cross-correlations take a universal form depending only on the exchange phase and the dynamical exponent, enabling experimental demonstration of anyonic statistics. This result can be interpreted as time-domain interference – braiding in time rather than spatial exclusion or real-space interferometry. Extension to hierarchical states shows that the semiclassical step-function description of quasiparticles fails at large statistical angles. Introducing a finite soliton width resolves this issue and enables quantitative modeling of charge-$ e/5$ quasiparticle collisions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 3 figures, Frontiers of Science Award Proceedings
Integrable Floquet Time Crystals in One Dimension
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Rahul Chandra, Mahbub Rahaman, Soumyabroto Majumder, Analabha Roy, Sujit Sarkar
We demonstrate the realization of a discrete-time crystal (DTC) phase in a family of periodically driven, one-dimensional quadratic lattice Hamiltonians that can be obtained using spin chains. These interactions preserve integrability while opening controllable gaps at resonant quasienergies and pinning the emergent quasienergy modes that are responsible for subharmonics. We demonstrate that the DTC phase is rigid in the parameter space of transverse field and an additional interaction like NNN coupling strength, with the drive frequency optimized to produce the strongest subharmonic response. We also provide a detailed phase portrait of the model, exhibiting a variety of new dynamical phases, such as a fragile time crystal and both spin-liquid and paramagnetic phases, as well as sharp quantum phase transitions between them. Finite-size scaling of the Floquet quasienergy splitting between the emergent subharmonic mode and its conjugate shows that the DTC lifetime diverges exponentially with system size. Our work thus establishes a novel mechanism for realizing robust, long-lived DTCs in one dimension, and paves the way for their experimental realization in near-term quantum simulators. Motivation for this work stems from the limitations of disorder-based stabilization schemes that rely on many-body localization and exhibit only prethermal or finite-lived plateaus, eventually restoring ergodicity. Disorder-free routes are therefore highly desirable. Integrable (or Floquet-integrable) systems provide an attractive alternative because their extensive set of conserved quantities and constrained scattering strongly restrict thermalization channels. Our construction exploits these integrable restrictions together with short-range NNN engineering to produce a clean, robust DTC that avoids the prethermal fragility of disordered realizations.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Comments and feedback are warmly welcomed. Please reach out to the corresponding author via email
Spin-wave propagation at low temperatures in YIG thin films on YSGG substrates
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
José Elias Abrão, Daan Weltens, Rhodri Mansell, Sebastiaan van Dijken, Lukáš Flajšman
The use of spin waves in magnetic thin films at cryogenic temperatures has long been hindered by the lack of a suitable material platform. Yttrium iron garnet (YIG) is the leading candidate, yet it is typically grown on gadolinium gallium garnet (GGG) substrates, which develop a large paramagnetic moment at low temperatures. This substrate effect limits spin-wave propagation. In this work, we demonstrate that thin YIG films grown on yttrium scandium gallium garnet (YSGG) substrates support robust spin-wave propagation in the Damon-Eshbach geometry, measurable down to 2 K under applied magnetic fields up to 150 mT. Compared with YIG/GGG, YIG/YSGG films exhibit narrower ferromagnetic resonance (FMR) linewidths at low temperatures and are free from the atomic interdiffusion effects that degrade the performance of YIG/GGG systems. These results establish YIG/YSGG thin films as a promising low-temperature platform, overcoming the intrinsic limitations of YIG/GGG and opening new opportunities for scalable magnonic and hybrid quantum devices operating under cryogenic conditions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 4 figures
Defects in hexagonal boron nitride for quantum technologies
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Tobias Vogl, Viktor Ivády, Isaac J. Luxmoore, Hannah L. Stern
Atomic defects in solid-state materials are building blocks for future quantum technologies, such as quantum communication networks, computers, and sensors. Until recently, a handful of defects in a small selection of host materials have been possible candidates. Recent developments have revealed that hexagonal boron nitride, a wide-bandgap two-dimensional material, hosts single-photon-emitting atomic defects with access to optically addressable electronic and nuclear spins at room temperature. Now, atomically thin quantum devices that operate at ambient conditions are a possibility. In this perspective, we discuss the recent progress, and challenges, in understanding the fundamental photophysics of defects in hBN, as well as specific opportunities they present for the development of quantum technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Spatially focused magnetic hyperthermia: comparison of MRSh and sLLG equations
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Zs. Iszály, A. Husztek, B. Mehmeti, Z. Erdélyi, Á. Szöőr, M. Béres, J. Korózs, V. Bacsó, I. Nándori, I. G. Márián
Magnetic hyperthermia with metallic nanoparticles is a therapeutic strategy that relies on heating cancer cells to levels sufficient to damage or destroy them. After injection, the nanoparticles accumulate in tumor tissues, where they transfer energy from the applied time-dependent magnetic field to the surrounding medium, thereby increasing the local temperature. This heating effect can be spatially focused (superlocalized) by combining AC and DC magnetic fields. Heat generation arises either from the rotation of the particle or from the rotation of its magnetic moment. The theoretical framework is provided by the Martsenyuk-Raikher-Shliomis (MRSh) equation for the former and the stochastic Landau-Lifshitz-Gilbert (sLLG) equation for the latter. However, by using the concept of magnetic and ordinary viscosity, the results of these approaches can be directly compared, which is our goal in this work, with special emphasis on their ability to achieve spatial localization. On the basis of this comparison, we propose the use of perpendicular AC and DC magnetic fields for image-guided thermal therapy with magnetic particle imaging.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 7 figures
On the Origin of Carrier Loss in Mg-Doped N-Polar GaN
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Masahiro Kamiyama, Shashwat Rathkanthiwar, Cristyan Quiñones-García, Seiji Mita, Dolar Khachariya, Pramod Reddy, Ronny Kirste, Ramón Collazo, Zlatko Sitar
The neutral $ (V_N-3Mg_{Ga})^0$ complex was found to be the primary compensator in Mg-doped, N-polar GaN. The experimental data showed a sharp drop in hole concentration once [Mg] exceeded ~$ 10^{19} cm^{-3}$ . Temperature-dependent Hall measurements, in conjunction with a charge balance model, revealed that the carrier loss was due to a drastic reduction in acceptor concentration ($ N_A$ ), suggesting that a significant fraction of Mg atoms incorporated in an electrically neutral configuration. A quantitative semi-empirical model based on the grand canonical formalism pointed to the formation of $ (V_N-3Mg_{Ga})^0$ complexes as the primary cause for the observed carrier loss.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Dynamic micromagnetism a la Ericksen-Leslie, allowing the Einstein-de Haas and Barnett effects
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
A model of dissipative micromagnetics coupled to elasticity is developed, following the procedures of the Ericksen-Leslie theory of nematic liquid crystals allowing for angular momentum due to magnetization. An outcome is the Landau-Lifshitz-Gilbert theory coupled to material spin. A further power-less augmentation to the angular momentum of the theory with classical kinetic energy density is also considered, which allows for plausible approaches to model the Einstein-de Haas and Barnett effects within continuum mechanics, as well as hard magnetic soft materials treated as constrained polar materials within the overall framework.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Twist dominates bending in the liquid crystal organization of bacteriophage DNA
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Pei Liu, Tamara Christiani, Zhijie Wang, Fei Guo, Mariel Vazquez, M. Carme Calderer, Javier Arsuaga
DNA frequently adopts liquid-crystalline conformations in both cells and viruses. The Oseen–Frank framework provides a powerful continuum description of these phases through three elastic moduli: splay ($ K_1$ ), twist or cholesteric ($ K_2$ ), and bending ($ K_3$ ). While $ K_1$ is typically assumed to dominate, the relative magnitude of $ K_2$ and $ K_3$ in confined DNA remains poorly understood. Here, we combine cryo-electron microscopy, liquid-crystal modeling, and knot theory to quantify this relationship in bacteriophage P4, whose genome is partially organized in a spool-like liquid-crystalline phase. We first show experimentally that the ordered DNA occupies three concentric layers within the capsid. We then formulate an Oseen–Frank model for this geometry and use it, together with the measured layer radii, to estimate the elastic ratio $ \alpha = K_3/K_2$ . We find $ \alpha \approx 0.0064$ , indicating that twist elasticity overwhelmingly dominates bending. To validate this result, we perform Langevin dynamics simulations of DNA trajectories and classify the resulting knots. The predicted knot distribution agrees with experimental data from P4, demonstrating consistency between elasticity, topology, and observed genome organization.
Soft Condensed Matter (cond-mat.soft), Biomolecules (q-bio.BM)
Systematic evolution of superconducting pairing strength and Seebeck coefficients in correlated infinite-layer La$_{1-x}$Sr$_x$NiO$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-07 20:00 EDT
Motoki Osada, Shusaku Imajo, Yuji Seki, Kousuke Ishida, Tsutomu Nojima, Kohei Fujiwara, Koichi Kindo, Yusuke Nomura, Atsushi Tsukazaki
The recently discovered superconducting infinite-layer nickelates offer a novel platform to explore an exotic pairing mechanism in multi-band systems towards high-temperature superconductivity and associated rich quantum phases, contrasting with cuprates. Here, we show that infinite-layer (La,Sr)NiO$ _2$ exhibits strong-coupling superconductivity, resilient to in-plane magnetic fields exceeding 47 T at optimal doping - more than twice the Pauli limit for conventional BCS superconductors. This violation becomes pronounced towards the underdoped regime, implying an intriguing evolution of pairing glue. The unexpected observation of positive Seebeck coefficients in this regime indicates the presence of nontrivial electron correlations. Furthermore, our comprehensive investigation across the superconducting dome reveals that the evolution of (thermo)electric normal-state properties - specifically, the sign changes of the Hall and Seebeck coefficients - coincide with the evolution of superconducting anisotropy and pairing strength. This demonstrates a definitive link between electron correlations and strong-coupling superconductivity in (La,Sr)NiO$ _2$ , contributing to a unified framework for understanding unconventional superconductivity.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
19 pages, 4 figures
Sci. Adv., 11, eadv6488 (2025)
Identifying non-equilibrium fluctuations in Intracellular Motion Using Recurrent Neural Networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-07 20:00 EDT
Tomas Basile, Natascha Leijnse, Malte Slot Lauridsen, Younes Farhangi Barooji, Amin Doostmohammadi, Karel Proesmans
Distinguishing active from passive dynamics is a fundamental challenge in understanding the motion of living cells and other active matter systems. Here, we introduce a framework that combines physical modeling, analytical theory, and machine learning to identify and characterize active fluctuations from trajectory data. We train a long short-term memory (LSTM) neural network on synthetic trajectories generated from well-defined stochastic models of active particles, enabling it to classify motion as passive or active and to infer the underlying active process. Applied to experimental trajectories of a tracer in the cytoplasm of a living cell, the method robustly identifies actively driven motion and selects an Ornstein-Uhlenbeck active noise model as the best description. Crucially, the classifier’s performance on simulated data approaches the theoretical optimum that we derive, and it also yields accurate estimates of the active diffusion coefficient. This integrated approach opens a powerful route to quantify non-equilibrium fluctuations in complex biological systems from limited data.
Statistical Mechanics (cond-mat.stat-mech)
Equilibrium properties of strongly confined fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
The statistical-mechanical study of the equilibrium properties of fluids, starting from the knowledge of the interparticle interaction potential, is essential to understand the role that microscopic interaction between individual particles play in the properties of the fluid. The study of these properties from a fundamental point of view is therefore a central goal in condensed matter physics. These properties, however, might vary greatly when a fluid is confined to extremely narrow channels and, therefore, must be examined separately. This thesis investigates fluids in narrow pores, where particles are forced to stay in single-file formation and cannot pass one another. The resulting systems are highly anisotropic: motion is free along the channel axis but strongly restricted transversely. To quantify these effects, equilibrium properties of the confined fluids are compared with their bulk counterparts, exposing the role of dimensionality. We also develop a novel theoretical framework based on a mapping approach that converts single-file fluids with nearest-neighbor interactions into an equivalent one-dimensional mixture. This exact isomorphism delivers closed expressions for thermodynamic and structural quantities. It allows us to compute the anisotropic pressure tensor and revises definitions of spatial correlations to take into account spatial anisotropy. The theory is applied to hard-core, square-well, square-shoulder, and anisotropic hard-body models, revealing phenomena such as zigzag ordering and structural crossovers of spatial correlations. Analytical predictions are extensively validated against Monte Carlo and molecular dynamic simulations (both original and from the literature), showing excellent agreement across the studied parameter ranges.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Ph.D Thesis defended at the University of Extremadura on the 12th of September of 2025
Learning Linear Regression with Low-Rank Tasks in-Context
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-10-07 20:00 EDT
Kaito Takanami, Takashi Takahashi, Yoshiyuki Kabashima
In-context learning (ICL) is a key building block of modern large language models, yet its theoretical mechanisms remain poorly understood. It is particularly mysterious how ICL operates in real-world applications where tasks have a common structure. In this work, we address this problem by analyzing a linear attention model trained on low-rank regression tasks. Within this setting, we precisely characterize the distribution of predictions and the generalization error in the high-dimensional limit. Moreover, we find that statistical fluctuations in finite pre-training data induce an implicit regularization. Finally, we identify a sharp phase transition of the generalization error governed by task structure. These results provide a framework for understanding how transformers learn to learn the task structure.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG), Machine Learning (stat.ML)
Dynamic Landau-Lifshitz-Bloch-Slonczewski equations for spintronics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Pascal Thibaudeau, Mouad Fattouhi, Liliana D. Buda-Prejbeanu
The atomistic Landau-Lifshitz-Gilbert equation is challenged when modeling spintronic devices where Joule heating is significant, due to its core assumption of a constant magnetization magnitude. Based on a statistical framework that treats the magnetization magnitude as a dynamic variable coupled to a thermal bath, we derive a dynamic Landau-Lifshitz-Bloch-Slonczewski set of equations for torques, that captures the transient, heating-induced demagnetization that occurs during high-current operation. Integrating these dynamic equations and comparing them to their stochastic equivalents reveals that both the energy landscape and switching dynamics in high-anisotropy systems are similarly modified. This approach yields accurate and accelerated predictions of critical currents and switching times.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
5 pages, 5 figures
Directed percolation transition to active turbulence driven by non-reciprocal forces
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-07 20:00 EDT
Juliane U. Klamser, Ludovic Berthier
We numerically study the collective dynamics of dense particle assemblies driven by non-reciprocal pairwise forces of amplitude $ \kappa$ . At a critical value $ \kappa_{\rm c}$ , the system undergoes a dynamical phase transition from an absorbing state ($ \kappa < \kappa_{\rm c}$ ) to a chaotic steady state ($ \kappa > \kappa_{\rm c}$ ). The chaotic phase is marked by nontrivial spatiotemporal velocity correlations and mixing, reminiscent of active turbulence in self-propelled systems. The sharp onset of chaos shows critical scaling consistent with the universality class of directed percolation. We argue that this transition is generic to a broad class of locally-driven, dense disordered materials.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
7 pages, 4 figures
Investigating into mechanisms of high temperature strength of refractory high-entropy alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Sai Anandhi Seetharaman, Soumyadipta Maiti, Ambesh Gupta, Beena Rai
The yield strength plateau of two BCC refractory high entropy alloys (RHEAs) - MoNbTaVW and MoNbTaW was examined through hybrid Monte Carlo and molecular dynamics (MC/MD) simulations. By analyzing atomic diffusivities derived from vacancy formation and migration energies around the edge dislocation cores, the number of critical atomic swaps were calculated at different temperatures. Using hybrid MC/MD simulations of these critical swaps, we demonstrate that above 1400K, the stress required to move the dislocations gets saturated, indicating the effect of Dynamic Strain Ageing (DSA) via cross core motion. Further simulations on random solid solutions (0 MC swaps) revealed a similar plateau effect at the intermediate temperatures. This was attributed to the additional athermal stress arising from lattice distortions due to solid solution strengthening. Our findings suggest that the yield strength plateau results from an interplay between the DSA-driven diffusion process and athermal stress. Specifically, the plateau emerges from DSA mechanisms in the presence of atomic diffusion, whereas in the absence of diffusion, it is governed by athermal statistical lattice distortions. This dual mechanism framework provides a comprehensive explanation for the experimentally observed Yield strength behavior in RHEAs at intermediate temperatures.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
32 pages, 9 figures
Symmetry of Dipolar Molecular Gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-10-07 20:00 EDT
Recent experiments with degenerate molecular gases dressed by elliptically polarized microwave fields have opened new avenues for engineering dipolar interactions. We identify a set of symmetries of the interaction potential, which generate degeneracies among the interaction parameters, and use these to classify the resulting spatial symmetries and equilibrium shapes of the gases. Exploiting these symmetries we analyze solutions including beyond-meanfield quantum fluctuations, and develop complementary variational results. We then map out the phase diagram of self-bound droplets and characterize their key properties.
Quantum Gases (cond-mat.quant-gas)
7 pages, 5 figures
Robust Kirkwood-Buff inversion in complex mixtures via reciprocal-space methods
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Understanding the relationship between microscopic structure and macroscopic thermodynamic properties is a central challenge in the study of complex fluids. The Kirkwood-Buff (KB) theory offers an elegant and powerful framework for bridging this gap by relating integrals over pair correlation functions to measurable thermodynamic quantities. In multicomponent systems, KB integrals connect directly to derivatives of thermodynamic potentials, including chemical potentials derivatives, partial molar volumes, and isothermal compressibility. While several computational methods exist to estimate KB integrals from molecular simulations, their application often demands careful treatment of finite-size effects and explicit extrapolation to the thermodynamic limit. Recently, alternative strategies based on the analysis of partial structure factors in reciprocal space have been proposed. Unlike real-space approaches, reciprocal-space methods avoid the additional truncation artifacts associated with direct integration or fluctuations in subensemble. They evaluate density fluctuations across the entire simulation box, fully accounting for periodic boundary conditions rather than relying on subdomains. As a result, these methods offer a compelling alternative, providing enhanced numerical stability for estimating KB integrals in complex mixtures. In this work, we extend, compare and validate these methods using binary and quaternary Lennard-Jones mixtures, as well as realistic molecular systems such as hexane-ethanol, water-urea, and aqueous NaCl mixtures. Our results provide practical guidelines for computing KB integrals and associated thermodynamic properties from canonical ensemble simulations, including recommendations on reciprocal-space extrapolation, uncertainty estimation, and linear algebra formulations of thermodynamic derivatives.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
J. Chem. Phys. 163, 134105 (2025)
Pronounced orbital-selective electron-electron correlation and electron-phonon coupling in V2Se2O
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Mingzhe Hu, Ziyin Song, Jingwen Cheng, Gexing Qu, Zhanghuan Li, Yu Huang, Jundong Zhu, Guangyu Zhang, Dacheng Tian, Lan Chen, Zhijun Tu, Hechang Lei, Xiaoping Ma, Huaixin Yang, Zhongxu Wei, Genfu Chen, Hongming Weng, Tian Qian, Hang Li
Orbital-selective many-body effects, in which electrons occupying different orbitals experience distinct interaction strengths, play a crucial role in correlated multiorbital materials. However, these effects usually manifest in a complex manner, obscuring their microscopic origins. Here, by combining angle-resolved photoemission spectroscopy measurements with theoretical calculations, we reveal pronounced orbital selectivity in both electron-electron correlation and electron-phonon coupling in the van der Waals material V2Se2O. Electron correlation induces distinct bandwidth renormalization exclusively in the V d_xy-derived band, while the bands mainly composed of the other d orbitals remain essentially unrenormalized. Orbital-resolved analyses identify that the filling number and the bandwidth are decisive factors governing orbital-dependent correlation. Simultaneously, the d_(xz/yz)-derived band exhibits a sharp kink anomaly, arising from enhanced coupling to high-energy phonon modes dominated by oxygen vibrations. Such pronounced orbital selectivity positions V2Se2O as a rare and prototypical platform for unravelling the microscopic mechanisms of orbital-selective electron-electron and electron-phonon interactions, and offers guiding principles for the design of correlated multiorbital materials.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
30 pages, 12 figures, 1 table
Non-resonant spin injection of exciton-polaritons with halide perovskites at room temperature
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Pablo Vaquer de Nieves, Elena Sendarrubias Arias-Camisón, Jorge Cuadra, Maksim Lednev, Raúl Gago, Luis Viña, Francisco José García Vidal, Johannes Feist, Ferry Prins, Carlos Antón Solanas
Exciton-polaritons, hybrid photon-exciton quasiparticles, constitute a useful platform for the study of light-matter interaction and nonlinear photonic applications. In this work, we realize a monolithic Tamm-plasmon microcavity embedding a thin film of two-dimensional halide perovskites with a tunable polymer spacer that controls the exciton-photon detuning. Angle-resolved optical spectroscopy at room temperature reveals the lower polariton branch dispersions in the linear regime for several detunings. Under circularly polarized, non-resonant laser excitation, the spin injection of high-energy excitons and their relaxation towards the lower polariton branch demonstrates its preservation, in contrast to the bare exciton case. The spin-polarized emission survives due to the fast decay of polaritons. Our results provide promising insights into the non-resonant spin control of polaritonic devices, including chiral lasers and switches.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
4 figures, 12 pages
Stability of graphene hyperbolic pseudospheres under harsh conditions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
T. P. C. Klaver, R. Gabbrielli, V. Tynianska, A. Iorio, D. Legut
We demonstrate the high stability of simulated graphene hyperbolic pseudospheres under large externally imposed deformations and high temperature annealing. Hyperbolic pseudospheres are produced in a two-step Molecular Dynamics simulation process. First, carbon atoms are forced down a thin three-dimensional volume of a chosen shape. During this extrusion process the carbon atoms form a precursor to graphene that is unrealistically less stable than graphite or diamond. Then the unstable carbon structure is annealed inside the thin volume at high temperature, turning the carbon into realistic polycrystalline, curved graphene. Point defects naturally appear in numbers and places that stabilize the graphene in the desired shape, without high residual stresses. We applied this new methodology to the creation of graphene hyperbolic pseudosphere surfaces, which reproduce analogs to some aspects of classical or quantum gravity. The free edges of the pseudosphere cause bending of the graphene. When these free edges are removed from the simulations by attaching periodic flat graphene sheets to the pseudosphere edges, the carbon atoms assume positions just some tenths of Å from the mathematical hyperbolic pseudosphere surface. In demanding tests of their stability, the hyperbolic pseudospheres proved stable against $ 20^\circ$ shearing or $ 20%$ elongation and then being released, which eventually raised their temperatures by $ \sim 300 \ \text{K}$ . Our methodology is relatively easy to use and offers a practical way to create simulated curved graphene surfaces of almost any shape. It allows for thorough testing in advance of the stability of graphene shapes that are to be produced experimentally.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
Accepted for publication in Applied Physics A
Repulsive-Interaction-Driven Topological Superconductivity in a Landau Level Coupled to an $s$-Wave Superconductor
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Koji Kudo, Ryota Nakai, Hiroki Isobe, J. K. Jain, Kentaro Nomura
A two-dimensional topologically nontrivial state of noninteracting electrons, such as the surface state of a three-dimensional topological insulator, is predicted to realize a topological superconductor when proximity-coupled to an ordinary $ s$ -wave superconductor. In contrast, noninteracting electrons partially occupying a Landau level, with Rashba spin-orbit coupling that lifts the spin degeneracy, fail to develop topological superconductivity under similar proximity coupling in the presence of the conventional Abrikosov vortex lattice. We demonstrate through exact diagonalization that, at half-filled Landau level, introducing a repulsive interaction between electrons induces topological superconductivity for a range of parameters. This appears rather surprising because a repulsive interaction is expected to inhibit, not promote, pairing, but suggests an appealing principle for realizing topological superconductivity: proximity-coupling a composite Fermi liquid to an ordinary $ s$ -wave superconductor.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
16 pages, 9 figures
AtomWorld: A Benchmark for Evaluating Spatial Reasoning in Large Language Models on Crystalline Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Taoyuze Lv, Alexander Chen, Fengyu Xie, Chu Wu, Jeffrey Meng, Dongzhan Zhou, Bram Hoex, Zhicheng Zhong, Tong Xie
Large Language Models (LLMs) excel at textual reasoning and are beginning to develop spatial understanding, prompting the question of whether these abilities can be combined for complex, domain-specific tasks. This question is essential in fields like materials science, where deep understanding of 3D atomic structures is fundamental. While initial studies have successfully applied LLMs to tasks involving pure crystal generation or coordinate understandings, a standardized benchmark to systematically evaluate their core reasoning abilities across diverse atomic structures has been notably absent. To address this gap, we introduce the AtomWorld benchmark to evaluate LLMs on tasks based in Crystallographic Information Files (CIFs), a standard structure representation format. These tasks, including structural editing, CIF perception, and property-guided modeling, reveal a critical limitation: current models, despite establishing promising baselines, consistently fail in structural understanding and spatial reasoning. Our experiments show that these models make frequent errors on structure modification tasks, and even in the basic CIF format understandings, potentially leading to cumulative errors in subsequent analysis and materials insights. By defining these standardized tasks, AtomWorld lays the ground for advancing LLMs toward robust atomic-scale modeling, crucial for accelerating materials research and automating scientific workflows.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI), Computation and Language (cs.CL)
Correlative Analysis of Iron-Driven Structural, Optical, and Magnetic Properties in Natural Biotite Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Raphaela de Oliveira, Yara Galvão Gobato, Ronei C. de Oliveira, José R. de Toledo, Verônica C. Teixeira, Angelo Malachias, Cesar R. Rabahi, Chunwei Hsu, Adilson J. A. de Oliveira, Herre. S. J. van der Zant, Ingrid D. Barcelos, Alisson R. Cadore
Biotite crystals are phyllosilicate trioctahedral micas with the general chemical formula K(Mg,Fe)3AlSi3O10(OH)2 that form a solid-solution series with iron-poor phlogopite and iron-rich annite endmembers. With a wide band gap energy and a layered structure with free surface charges, biotite nanosheets can be readily obtained by cleavage methods and used as dielectrics in nanodevice fabrication for the next generation of electronics and energy harvesting. Here, a comprehensive study of biotite samples with different iron concentrations and oxidation states is presented. Structural, optical, magneto-optical, and magnetic characterizations were performed using several experimental techniques, including state-of-the-art synchrotron-based techniques, to correlate the iron chemistry (content and oxidation state) with the macroscopic properties of both minerals. The study reveals a nanoscale-homogeneous Fe distribution via synchrotron X-ray fluorescence mapping, defect-mediated optical transitions modulated by Fe3+/Fe2+ ratios, and temperature-dependent magnetic transitions from paramagnetism to competing ferro-/antiferromagnetic interactions. Furthermore, the use of these biotite crystals as substrates for ultrathin heterostructures incorporating monolayer (ML) MoSe2 is explored by magneto photoluminescence at cryogenic temperatures. The results show that the presence of iron impurities in different oxidation states significantly impacts the valley properties for ML-MoSe2. Overall, these findings offer a comprehensive interpretation of the physical properties of bulk biotites in a correlative approach, serving as a robust reference for future studies aiming to explore biotites in their ultrathin form.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
17 pages, 5 figs
Finite temperature dopant-induced spin reorganization explored via tensor networks in the two-dimensional $t$-$J$ model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Yintati Zhang, Aritra Sinha, Marek M. Rams, Jacek Dziarmaga
Doped Mott insulators host intertwined spin-charge phenomena that evolve with temperature and can culminate in stripe order or superconductivity at low temperatures. The two-dimensional $ t$ -$ J$ model captures this interplay yet finite-temperature, infinite-size calculations remain difficult. Using purification represented by a tensor network - an infinite projected entangled-pair state (iPEPS) ansatz - we simulate the $ t$ -$ J$ model at finite temperature directly in the thermodynamic limit, reaching temperatures down to one tenth of the hopping rate and hole concentrations up to one quarter of the lattice sites. Beyond specific heat, uniform susceptibility, and compressibility, we introduce dopant-conditioned multi-point correlators that map how holes reshape local exchange. Nearest-neighbor hole pairs produce a strong cooperative response that reinforces antiferromagnetism on the adjacent parallel bonds, and single holes weaken nearby antiferromagnetic bonds; d-wave pairing correlations remain short-ranged over the same window. These results provide experiment-compatible thermodynamic-limit benchmarks and establish dopant-conditioned correlators as incisive probes of short-range spin-texture reorganization at finite temperature.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
15 pages, 13 figures
Electronic and thermal properties of the phase-change memory material, Ge2Sb2Te5, and results from spatially resolved transport calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Kishor Nepal, Aashish Gautam, Ridwan Hussein, Konstantinos Konstantinou, Stephen. R. Elliott, Chinonso Ugwumadu, David A. Drabold
We report new insights into the electronic, structural, and transport (heat and charge) properties of the phase-change memory material Ge2Sb2Te5. Using realistic structural models of Konstantinou et. al. [Nat. Commun. 10, 3065 (2019)], we analyze the topology, electronic states, and lattice dynamics with density functional methods, including hybrid-functional calculations and machine-learned interatomic potentials. The Kohn-Sham orbitals near the Fermi level display a strong electron-phonon coupling, and exhibit large energy fluctuations at room temperature. The conduction tail states exhibit larger phonon-induced fluctuations than the valence tail states. To resolve transport at the atomic scale, we employ space-projected electronic conductivity and site-projected thermal conductivity methods. Local analysis of heat transport highlights the role of filamentary networks dominated by Te, with Sb and Ge making progressively smaller contributions.
Materials Science (cond-mat.mtrl-sci)
Refined spin Hamiltonian on the Cairo pentagonal lattice of Bi2Fe4O9
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Emma Y. Lenander, Frida B. Nielsen, Jakob Lass, Ursula B. Hansen, Kristine M. L. Krighaar, Asbjørn Preuss, Tobias Weber, Mechthild Enderle, Henrik Jacobsen, Uwe Stuhr, Ryoichi Kajimoto, Mitsutaka Nakamura, Manfred Burianek, Andrea Kirsch, Henrik M. Rønnow, Kim Lefmann, Pascale P. Deen
The frustrated magnet Bi2Fe4O9 has been reported to exhibit complex spin dynamics coexisting with conventional spin wave excitations. The magnetic Fe3+ (S = 5/2) ions are arranged into a distorted two-dimensional Cairo pentagonal lattice with weak couplings between the layers, developing long-ranged non-collinear antiferromagnetic order below 245 K. In order to enable studies and modelling of the complex dynamics close to TN, we have reexamined the magnetic excitations across the complete energy scale (0 < E < 90 meV) at 10 K. We discover two distinct gaps, which can be explained by introducing, respectively, easy axis and easy plane anisotropy on the two unequivalent Fe-sites. We develop a refined spin Hamiltonian that accurately accounts for the dispersion of essentially all spin-wave branches across the full spectral range, except around 40 meV, where a splitting and dispersion are observed. We propose that this mode is derived from phonon hybridization. Polarisation analysis shows that the system has magnetic anisotropic fluctuations, consistent with our model. A continuum of scattering is observed above the spin wave branches and is found to principally be explained by an instrumental resolution effect. The full experimental mapping of the excitation spectrum and the refined spin Hamiltonian provides a foundation for future quantitative studies of spin waves coexisting with unconventional magnetic fluctuations in this frustrated magnet found at higher temperatures.
Strongly Correlated Electrons (cond-mat.str-el)
Systematic cRPA study of two-dimensional MA$_2$Z$_4$ materials: From unconventional screening to correlation-driven instabilities
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
F. Bagherpour, Y. Yekta, H. Hadipour, E. Sasioglu, A. Khademi, S. A. Jafari, I. Mertig, S. Lounis
Understanding the interplay between screening, electronic correlations, and collective excitations is essential for the design of two-dimensional quantum materials. Here, we present a comprehensive first-principles study of more than 60 MA$ _2$ Z$ 4$ monolayers, encompassing semiconducting, metallic, cold-metallic, magnetic, and topological phases. Using the constrained random phase approximation (cRPA), we compute material-specific effective Coulomb interaction parameters $ U$ , $ U’$ , and $ J$ , including their spatial dependence across distinct correlated subspaces defined by local coordination and crystal symmetry. In semiconducting compounds, long-range nonlocal interactions persist, revealing unconventional screening and suggesting strong excitonic effects beyond simple dielectric models. In cold-metallic systems, sizable long-range Coulomb interactions remain despite the presence of free carriers, highlighting their atypical metallic screening. Among 33-valence-electron compounds, we find $ U{\mathrm{eff}} > W$ in the $ \beta_2$ phase, indicating proximity to charge-density-wave or Mott instabilities. Several V- and Nb-based systems exhibit intermediate-to-strong correlation strength, with $ U/W > 1 $ in multiple cases. Using cRPA-derived Stoner parameters, we identify magnetic instabilities in various V-, Nb-, Cr-, and Mn-based compounds. Finally, selected cold-metallic systems display plasmon dispersions that deviate from the conventional $ \sqrt{q}$ behavior, revealing nearly non-dispersive low-energy modes. These results position MA$ _2$ Z$ _4$ monolayers as a versatile platform for investigating correlation-driven instabilities and emergent collective behavior in two dimensions.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
20 pages, 5 figures, 5 tables
Geometric Mechanics of Thin Periodic Surfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Wenqian Sun, Yanxin Feng, Christian D. Santangelo, D. Zeb Rocklin
Thin surfaces are ubiquitous in nature, from leaves to cell membranes, and in technology, from paper to corrugated containers. Structural thinness imbues them with flexibility, the ability to easily bend under light loads, even as their much higher stretching stiffness can bear substantial stresses. When surfaces have periodic patterns of either smooth hills and valleys or sharp origami-like creases this can substantially modify their mechanical response. We show that for any such surface, there is a duality between the surface rotations of an isometric deformation and the in-plane stresses of a force-balanced configuration. This duality means that of the six possible combinations of global in-plane strain and out-of-plane bending, exactly three must be isometries. We show further that stressed configurations can be expressed in terms of both the applied deformation and the isometric deformation that is dual to the pattern of stress that arises. We identify constraints rooted in symplectic geometry on the three isometries that a single surface can generate. This framework sheds new light on the fundamental limits of the mechanical response of thin periodic surfaces, while also highlighting the role that continuum differential geometry plays in even sharply creased origami surfaces.
Soft Condensed Matter (cond-mat.soft), Differential Geometry (math.DG)
Experimental observation of frustration and large anomalous Nernst effect in metallo-molecular spin Kondo lattice interfaces
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Servet Ozdemir, Matthew Rogers, Conor J. McCluskey, Raymond G. McQuaid, Mannan Ali, Gavin Burnell, Joseph Barker, B J Hickey, Oscar Cespedes
Frustration in Kondo spin lattice systems has led to the emergence of both spin liquids that could be chiral and strange metals that deviate from Fermi liquid behaviour when not in their antiferromagnetic ground state. In two dimensions (2D), where deviations from bulk systems are expected, Kondo spin lattice emergence have recently been observed in van der Waals systems. Metallo-molecular interfaces of supramolecular lattices have also been suggested as an alternative 2D Kondo spin lattice system where a single-ion Kondo effect as well as an inter spin-site Ruderman-Kittel-Kasuya-Yosida (RKKY) coupling has been demonstrated in scanning tunnelling spectroscopy (STS) studies. Here, going beyond ultrahigh vacuum STS studies on metallo-molecular interfaces, we report a metastable frustrated antiferromagnetic state, with ultra-high spin freezing temperatures (T_f), ranging from 240 K to 300 K on the interfaces of highly textured Pt(111) and Pt(111)/Co films with organic molecules grown in ultra-high vacuum 10^(-10) mbar. In the vicinity of the spin-freezing transition, we measure a large anomalous Nernst effect (ANE) in the Pt/Co/molecular heterostructure, with a Nernst coefficient of at least 3 microV per K. Our results suggest a 2D metallo-molecular Kondo spin lattice with high temperature quantum correlations where an ANE beyond magnetisation is manifested around room temperature.
Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 17 figures
Anyon interactions in the Chern–Simons–Landau–Ginzburg model of the fractional quantum Hall effect
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-07 20:00 EDT
The interactions of anyonic quasi-particles (vortices) in the Chern–Simons extension of the Ginzburg–Landau model is investigated and we show that it manifestly realizes a hybridization of type I/II superconductivity. Through Gauss’ law, each vortex simultaneously carries a flux quantum and a proportional Noether charge, thereby realizing an anyonic excitation. The Chern–Simons coupling also modifies the screening structure of the gauge fields, producing complex-conjugate masses that yield a common penetration depth with an oscillatory phase. This altered asymptotic behavior breaks the conventional type-I/type-II dichotomy of the Ginzburg–Landau model. As a result, vortex anyons experience short-range repulsion and long-range attraction, enabling the formation of separated multi-vortex bound states with non-monotonic interaction energy.
Superconductivity (cond-mat.supr-con), High Energy Physics - Theory (hep-th)
10 pages, 2 figures
Chasing Anharmonicities in Polarization-Orientation Raman Spectra of Acene Crystals with Machine Learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Paolo Lazzaroni, Shubham Sharma, Mariana Rossi
We present a first-principles machine-learning computational framework to investigate anharmonic effects in polarization-orientation (PO) Raman spectra of molecular crystals, focusing on anthracene and naphthalene. By combining machine learning models for interatomic potentials and polarizability tensors, we enable efficient, large-scale simulations that capture temperature-dependent vibrational dynamics beyond the harmonic approximation. Our approach reproduces key qualitative features observed experimentally. We show, systematically, what are the fingerprints of anharmonic lattice dynamics, thermal expansion, and Raman tensor symmetries on PO-Raman intensities. However, we find that the simulated polarization dependence of Raman intensities shows only subtle deviations from quasi-harmonic predictions, failing to capture the pronounced temperature-dependent changes that have been reported experimentally in anthracene. We propose that part of these inconsistencies stem from the impossibility to deconvolute certain vibrational peaks when only experimental data is available. This work therefore provides a foundation to improve the interpretation of PO-Raman experiments in complex molecular crystals with the aid of theoretical simulations.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Magnetic Moment Fragmentation in an All-in-All-out Pyrochlore $\mathrm{Nd_2Sn_2O_7}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Yi Luo, Matthew Powell, Joseph A. M. Paddison, Brenden R. Ortiz, J. Ross Stewart, Joseph W. Kolis, Adam A. Aczel
We report single crystal neutron spectroscopy and bulk characterization on hydrothermally grown $ \mathrm{Nd_2Sn_2O_7}$ , revealing magnetic moment fragmentation embedded within the all-in-all-out ordered state. The spectra reveal a nearly flat band with pinch-point momentum dependence accompanied by dispersive branches that produce half-moon features across multiple Brillouin zones. These defining signatures are captured quantitatively by a minimal dipolar-octupolar spin Hamiltonian, demonstrating excellent agreement between experiment and theory. The higher flat-mode energy helps account for the absence of dynamical interference in prior $ \mathrm{\mu SR}$ studies, while the lack of any photon-like excitation imposes strict constraints on the proposed Coulombic antiferromagnet scenario. Our results extend moment fragmentation to $ \mathrm{Nd_2Sn_2O_7}$ and identify it as a clean, tractable platform for quantitative exploration of emergent gauge field physics in frustrated magnets.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures, 1 table in main text; 10 pages, 5 figures, 2 tables in Supplementary Material
A network-based approach to measure granule size distribution for discrete element modeling of granulation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
Shubham Jain, Anurag Tripathi, Jayanta Chakraborty, Jitendra Kumar
Drum granulation is a size enlargement process where granular material is agitated with a liquid binder to form larger size granules. Discrete element modeling is increasingly being used to better understand and investigate the granulation process. However, unlike experiments the measurement of granule size within a DEM framework often necessitates an explicit quantitative definition of a granule and a corresponding granule identification method. In this work, we show that the existing definitions and the associated methods in literature are ineffective at identifying granules for dense flows such as during drum granulation. We propose an improved definition and granule identification method based on community-detection used in network science literature. The proposed method better identifies granules in a drum granulator as benchmarked against liquid-settling. We also vary granulation process parameters like liquid content and fill level and study their effect on the cumulative granule size distribution attained after drum granulation. We find that the existing granule-identification methods fail to reproduce the well-known effects of process parameters on the cumulative granule size distribution. The proposed method, based on community detection, reproduces the effects with better accuracy.
Soft Condensed Matter (cond-mat.soft)
Effect of ice nucleating proteins on the structure-property relationships of ice: A molecular dynamics study
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-07 20:00 EDT
A. K. Shargh, C. D. Stiles, J. A. El-Awady
Ice-nucleating proteins (INPs) are a unique class of biological macromolecules that catalyze the freezing of supercooled water far more efficiently than homogeneous nucleation. Their remarkable efficiency has motivated applications across diverse sectors, including agricultural frost protection, food processing and packaging, biomedical cryopreservation, and even strategies for mitigating glacier ice loss. The ice-nucleation performance of INPs and the mechanical behavior of the ice they produce depend strongly on their structural and biochemical characteristics. However, the links between INP properties, the resulting ice microstructure, and their mechanical behavior have yet to be systematically established. In this study, coarse-grained molecular dynamics (CGMD) simulations using the machine-learned ML-BOP potential are employed to investigate how varying INP densities influence the ice nucleation temperature, the resulting ice microstructure, and the mechanical behavior of the formed ice under creep tensile loading. We find that, depending on their density, INPs can significantly raise the ice nucleation rate while altering the grain structure of ice. Our simulations reveal that INP-assisted nucleation leads to faster stabilization of the resulting polycrystalline ice composed of hexagonal ice (ice Ih) and cubic ice (ice Ic) as compared to nucleation in pure water. Moreover, higher INP densities and smaller ice grain sizes reduce the overall yield stress, while promoting diffusion-accommodated grain boundary sliding creep. These findings provide molecular-level insight into how INPs influence both the nucleation process and the mechanical behavior of ice, highlighting a pathway to engineer ice with tailored stability for real-world settings, including human activities and infrastructure in polar and icy environments.
Soft Condensed Matter (cond-mat.soft)
Variational optimization of projected entangled-pair states on the triangular lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Jan Naumann, Jens Eisert, Philipp Schmoll
We introduce a general corner transfer matrix renormalization group algorithm tailored to projected entangled-pair states on the triangular lattice. By integrating automatic differentiation, our approach enables direct variational energy minimization on this lattice geometry. In contrast to conventional approaches that map the triangular lattice onto a square lattice with diagonal next-nearest-neighbour interactions, our native formulation yields improved variational results at the same bond dimension. This improvement stems from a more faithful and physically informed representation of the entanglement structure in the tensor network and an increased number of variational parameters. We apply our method to the antiferromagnetic nearest-neighbour Heisenberg model on the triangular and kagome lattice, and benchmark our results against previous numerical studies.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Atomistic Insights into the Degradation of Metal Phthalocyanine Catalysts during Oxygen Reduction Reaction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Oxygen reduction catalysts frequently suffer from degradation under harsh operating conditions, and the limited understanding of the underlying mechanisms hampers the development of effective mitigation strategies. In this study, we integrate first-principles calculations with a time-dependent microkinetic model to investigate the deactivation pathways of six highly active metal phthalocyanines (MPc, M = Cr, Mn, Fe, Ru, Rh, and Ir) during the oxygen reduction reaction (ORR). We quantitatively assess the ORR processes, hydrogen peroxide generation, radical generation, and three primary degradation mechanisms, namely carbon oxidation, nitrogen protonation, and demetallation, through a reaction network involving 40 chemical species and 75 elementary reactions. Our findings reveal that the dominant degradation mechanism varies significantly across the MPcs. Under typical alkaline conditions, the primary byproducts arise from carbon oxidation, driven by .OH radical attack and structural reorganization of surface adsorbates, and from protonation at either the metal center or nitrogen sites. In the kinetics-controlled region, the ORR activity follows the order of RhPc > IrPc > FePc > MnPc > RuPc > CrPc. Notably, RhPc and IrPc demonstrate both higher ORR activity and greater stability than the widely studied FePc under elevated potentials.
Materials Science (cond-mat.mtrl-sci)
The two conduction bands of monolayer CrSBr on Au
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Yogal Prasad Ghimirey, Laxman Nagireddy, Cephise Cacho, Neil R. Wilson, Matthew D. Watson
We report the electronic structure of monolayer CrSBr exfoliated onto mica template-stripped gold substrates. Angle-resolved photoemission spectroscopy reveals charge transfer from the substrate, populating the conduction band of monolayer CrSBr, accompanied by a pronounced reduction in the quasiparticle band gap. Furthermore, we observe two separate conduction bands that exhibit a splitting at the X point. This indicates a breaking of glide-mirror symmetry, which in the bulk or in a free-standing monolayer protects the band degeneracies at the Brillouin zone boundary. Our results demonstrate that ultraflat gold substrates do more than modify carrier densities and screening: they can lift symmetry-protected degeneracies and thus fundamentally reshape the band topology of 2D materials.
Strongly Correlated Electrons (cond-mat.str-el)
Fermionic influence superoperator for transport through Majorana zero modes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-07 20:00 EDT
Jia-Lin Pan, Zi-Fan Zhu, Shixuan Chen, Yu Su, Yao Wang
In recent years, the study of Majorana signatures in quantum transport has become a central focus in condensed matter physics. Here, we present a rigorous and systematic derivation of the fermionic superoperator describing the open quantum dynamics of electron transport through Majorana zero modes, building on the techniques introduced in Phys. Rev. B 105, 035121 (2022). The numerical implementation of this superoperator is to construct its differential equivalence, the hierarchical equations of motion (HEOM). The HEOM approach describes the system-bath correlated dynamics. Furthermore, we also develop a functional derivative scheme that provides exact expressions for the transport observables in terms of the auxiliary density operators introduced in the HEOM formulation. The superoperator formalism establishes a solid theoretical foundation for analyzing key transport signatures that may uncover the unique characteristics of Majorana physics in mesoscopic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 2 figures
Controlling an altermagnetic spin density wave in the kagome magnet CsCr3Sb5
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Zihao Huang, Chenchao Xu, Yande Que, Yi Liu, Ranjith Shivajirao, Zheng Jue Tong, Amit Kumar, Chao Cao, Guang-Han Cao, Hong-Jun Gao, Bent Weber
The interplay of charge and spin orders lies at the heart of correlated electron physics and plays a critical role in the emergence of unconventional quantum phases. Kagome magnets provide a particularly promising platform to investigate these phenomena, owing to their geometrically frustrated lattice structure. However, resolving spin and charge orders microscopically and establishing ways to control them remain fundamental challenges. Here, we demonstrate magnetic field control of an altermagnetic spin density wave order intertwined with charge density wave order in kagome magnet CsCr3Sb5. Scanning tunneling microscopy down to deep cryogenic temperature of 50 mK reveals two previously unreported charge density wave orders in the Sb surface. Density functional theory confirms that one of them is coupled to a spin density wave with an altermagnetic ground state. The charge density waves can be tuned in both amplitude and phase by an external magnetic field, reflected in domain switching and stripe sliding of the charge density wave. Our findings deepen the understanding of symmetry-breaking in kagome systems, providing a tunable platform to explore the interplay of electronic correlation with emergent quantum magnetism.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
23 pages, 5 figures
Emergent Electronic Flat Bands Through Dislocation Defect Phase Patterning: Effective One-Dimensional Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Recent theoretical work has predicted that dislocation patterning induces anisotropic flat bands in the electronic band diagram, which can lead to unusual effects such as unconventional superconductivity. This work develops a reduced-dimensional framework to provide insights into their origin. An effective one-dimensional dislocation potential is constructed by averaging over the spatial distributions of dislocations along a singular direction. The resulting model introduces a parameter that quantifies the strain modulation, thereby providing a transparent approach to analyze the role of dislocation strain in leading to flat band formation.
Strongly Correlated Electrons (cond-mat.str-el)
To appear in Journal of Applied Mechanics
Comparing fine-tuning strategies of MACE machine learning force field for modeling Li-ion diffusion in LiF for batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Nada Alghamdi, Paolo de Angelis, Pietro Asinari, Eliodoro Chiavazzo
Machine learning interatomic potentials (MLIPs) are transforming materials science and engineering by enabling the study of complex phenomena, such as those critical to battery operation. In this work, we benchmark the MACE machine learning model against a well-trained DeePMD potential for predicting interstitial lithium diffusivity in LiF, a key component in the solid electrolyte interphase in Li ion batteries. Our results demonstrate that the MACE-MPA-0 foundational model achieves comparable accuracy to well-trained DeePMD, in predicting key diffusion properties based on molecular dynamics simulation, while requiring minimal or no training data. For instance, the MACE-MPA-0 predicts an activation energy Ea of 0.22 eV, the fine-tuned model with only 300 data points predicts Ea = 0.20 eV, both of which show good agreement with the DeePMD model reference value of Ea = 0.24 eV. In this work, we provide a solid test case where fine-tuning approaches - whether using data generated for DeePMD or data produced by the foundational MACE model itself - yield similar robust performance to the DeePMD potential trained with over 40,000 actively learned data, albeit requiring only a fraction of the training data.
Materials Science (cond-mat.mtrl-sci)
13 pages, 5 figures
Role of chromium oxides and carbides in strengthening CoCrFeNi multi-principle element alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-07 20:00 EDT
Artur Olejarz, Wenyi Huo, Anna Kosinska, Maciej Zielinski, Tomasz Stasiak, Marcin Chmielewski, Wojciech Chmurzynski, Max Rae Chu, Michael Patrick Short, Lukasz Kurpaska
Multi-principal element alloys (MPEAs) can potentially offer exceptional material properties, but their complex, costly manufacturing limits their scalability. Chemical complexity and complex manufacturing processes lead to the formation of some secondary phases, which have a significant impact on the final properties. In this work, chromium compound dispersoid enhancements (Cr- oxides and carbides) were formed in CoCrFeNi MPEAs to enhance their microstructural and high-temperature mechanical properties. A single FCC phase was observed in the arc melted (AM) samples, chromium oxides were detected in the gas-atomized (GA) samples, and Cr2O3 with Cr23C6 or Cr7C3 was found in the mechanically alloyed (MA)samples depending on the sintering temperature. Mechanical tests at room temperature and 575°C, where no phase evolution is expected, showed that the GA samples with oxides achieved enhanced mechanical properties at 575°C. This was co-induced by precipitation strengthening, recrystallization suppression, and twinning-induced plasticity. The MA samples with carbides exhibited high strength but low ductility, with Cr7C3 outperforming Cr23C6 because of its lower hardness and twinning effects. This work links chromium compound evolution to mechanical performance of MPEAs, offering insights to optimize HEA production for high-temperature applications through controlled phase formation.
Materials Science (cond-mat.mtrl-sci)
11 figures, 55 pages
Materials Science & Engineering A 945 (2025) 149058
Field-Theoretic Simulation of Dean-Kawasaki Dynamics for Interacting Particles
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-07 20:00 EDT
Jaehyeok Jin, Chen Liu, David R. Reichman
The formulation of a fluctuating hydrodynamic theory for interacting particles is a crucial step in the theoretical description of liquids. The microscopic mappings proposed decades ago by Dean and Kawasaki have played a central role in the analytical treatment of such problems. However, the singular mathematical nature of the density distributions used in these derivations raises concerns about the validity and practical utility of the resulting stochastic partial differential equations, particularly for direct numerical simulations. Recent efforts have centered on establishing a rigorous coarse-graining procedure to regularize the effective Dean-Kawasaki equation. Building on this foundation, we numerically investigate weakly interacting fluids within such a regularized framework for the first time. Our work reveals, at the level of structural correlations, the effects of regularization on the Dean-Kawasaki formalism and paves the way for improved numerical approaches to simulate fluctuating hydrodynamics in liquids.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
21 pages, 10 figures (Supplemental Material: 17 pages, 7 figures, 2 tables)
Casimir Stabilization of Fluctuating Electronic Nematic Order
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-07 20:00 EDT
Ola Carlsson, Sambuddha Chattopadhyay, Jonathan B. Curtis, Frieder Lindel, Lorenzo Graziotto, Jérôme Faist, Eugene Demler
Vacuum cavity control of quantum materials is the engineering of quantum materials systems through electromagnetic zero-point fluctuations. In this work we articulate a generic mechanism for vacuum optical control of correlated electronic order: Casimir control, where the zero-point energy of the electromagnetic continuum, the Casimir energy, depends on the properties of the material system. To assess the experimental viability of this mechanism we focus on the Casimir stabilization of fluctuating nematic order. In nematic Fermi liquids, different orientations of the electronic order are often energetically degenerate. Thus, while local domains of fixed orientation may form, thermal disordering inhibits long range order. By engineering the electromagnetic environment of the electronic system, however, we show that the Casimir energy can be used as a tool to preferentially stabilize particular orientations of the nematic order. As a concrete example, we examine the interplay between a birefringent crystal – which sources an anisotropic electromagnetic environment – and a quantum Hall stripe system, an archetypal nematic Fermi fluid. We show that for experimentally feasible setups, the anisotropy induced by the orientation dependent Casimir energy can be $ 10^4$ times larger than other mechanisms known to stabilize quantum Hall stripes. This finding convincingly implies that our setting may be realized with currently available experimental technology. Having demonstrated that the Casimir energy can be used to stabilize fluctuating nematic order, we close by discussing the implications for recent terahertz cavity experiments on quantum Hall stripes, as well as pave the road towards broader Casimir control of competing correlated electronic phases.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)