CMP Journal 2025-05-27
Statistics
Nature: 1
Nature Physics: 1
arXiv: 93
Nature
A coordinated cellular network regulates tolerance to food
Original Paper | Antigen presentation | 2025-05-26 20:00 EDT
Anna Rudnitsky, Hanna Oh, Maya Margolin, Bareket Dassa, Inbar Shteinberg, Liat Stoler-Barak, Ziv Shulman, Ranit Kedmi
To absorb nutrients and support commensal microbes, the host induces tolerogenic immune responses via peripheral regulatory T cells (pTregs) 1,2. Prior studies identified type 1 dendritic cells (cDC1) as initiators of dietary pTregs3. However, we now report that food-specific pTreg cells are exclusively induced by the recently identified RORγt APCs4-8 and not by cDCs. Instead, our data suggest that pTreg-cDC1 interactions in steady-state limit the expansion of food-specific CD8αβ T cells. This regulation breaks during infection or food poisoning, enabling dietary CD8αβ T cells to expand and acquire effector functions in response to mimicked food antigens. Unlike in typical infections, after the pathogen is cleared, dietary CD8αβ T cells do not expand in response to their corresponding dietary antigens. Thus, we propose that in response to dietary antigens, tolerance is mediated by a circuit of dedicated antigen-presenting cells (APCs) and T cells. When the host is challenged by infection, this circuit permits the transient expansion of protective effector responses without compromising the overall strategy of tolerance that ensures safe food consumption.
Antigen presentation, Antigen-presenting cells, Immune tolerance, Mucosal immunology
Nature Physics
Critical fermions are universal embezzlers
Original Paper | Phase transitions and critical phenomena | 2025-05-26 20:00 EDT
Lauritz van Luijk, Alexander Stottmeister, Henrik Wilming
Universal embezzlers are bipartite quantum systems from which any entangled state may be extracted to arbitrary precision using local operations while perturbing the system arbitrarily little. Here we show that a universal embezzler can be created by bipartitioning any local, translation-invariant, critical free-fermionic many-body system on a one-dimensional lattice. The same property holds for locally interacting spin chains that are dual to the critical fermionic models by the Jordan-Wigner transformation. Furthermore, for any finite error and any targeted entangled state, a finite length of the chain is sufficient to embezzle said state within the given error. Hence, universal embezzlement is not restricted to the thermodynamic limit. As well as establishing the ubiquity of universal embezzlers in many-body physics, on a technical level, our main result establishes that the half-chain observable algebras associated with ground-state sectors of the given models are type III1 factors.
Phase transitions and critical phenomena, Quantum information, Theoretical physics
arXiv
Quantum Spin Liquids in Pyrochlore Magnets With Non-Kramers Local Moments
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Tony An, Félix Desrochers, Yong Baek Kim
Numerous experiments on pyrochlore oxides Pr$ _2$ (Zr, Sn, Hf, Ir)$ _2$ O$ _7$ with non-Kramers Pr$ ^{3+}$ ions suggest that they support a quantum spin liquid (QSL) ground state, but the precise nature of the QSL remains unclear. Quantum spin ice with dominant dipolar Ising and smaller quadrupolar transverse exchange interactions is one such candidate, but a dominant inelastic neutron scattering signal suggests that such a picture may not be consistent with experimental results. The microscopic exchange couplings of these compounds are also not known, leaving room for many possible QSL states. In this work, we use Schwinger boson mean-field theory supplemented by a projective symmetry group classification to study possible $ \mathbb{Z}_2$ QSLs in pyrochlore magnets with dipolar-quadrupolar non-Kramers local moments. We build a mean-field phase diagram and find four QSLs in the frustrated region of parameter space that are consistent with inelastic signals observed in neutron scattering data on Pr$ _2$ Zr$ _2$ O$ _7$ and Pr$ _2$ Hf$ _2$ O$ _7$ . Among these, two robust QSLs occur in the regime with dominant transverse exchange rather than Ising exchange. We then compute the static and dynamic spin structure factors for these QSL candidates, which can be used to distinguish them in neutron scattering experiments.
Strongly Correlated Electrons (cond-mat.str-el)
10+9 pages, 6 figures
Universal temperature-dependent power law excitation gaps in frustrated quantum spin systems harboring order-by-disorder
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Alexander Hickey, Jeffrey G. Rau, Subhankar Khatua, Michel J. P. Gingras
When magnetic moments are subject to competing or frustrated interactions, continuous degeneracies that are not protected by any symmetry of the parent Hamiltonian can emerge at the classical (mean-field) level. Such “accidental” degeneracies are often lifted by both thermal and quantum fluctuations via a mechanism known as order-by-disorder (ObD). The leading proposal to detect and characterize ObD in real materials, in a way that quantitatively distinguishes it from standard energetic selection, is to measure a small fluctuation-induced pseudo-Goldstone gap in the excitation spectrum. While the properties of this gap are known to leading order in the spin wave interactions, in both the zero-temperature and classical limits, the pseudo-Goldstone (PG) gap in quantum magnets at finite temperature has yet to be characterized. Using non-linear spin wave theory, we compute the PG gap to leading order in a $ 1/S$ expansion at low temperature for a variety of frustrated quantum spin systems. We also develop a formalism to calculate the PG gap in a way that solely uses linear spin-wave theory, circumventing the need to carry out tedious quantum many-body calculations. We argue that, at leading order, the PG gap acquires a distinct power-law temperature dependence, proportional to either $ T^{d+1}$ or $ T^{d/2+1}$ depending on the gapless dispersion of the PG mode predicted at the mean-field level. Finally, we examine the implications of these results for the pyrochlore oxide compound Er$ _2$ Ti$ _2$ O$ _7$ , for which there is compelling evidence of ObD giving rise to the experimentally observed long-range order.
Strongly Correlated Electrons (cond-mat.str-el)
23 pages, 5 figures
Nonuniversal equation of state for Rabi-coupled bosonic gases: a droplet phase
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-27 20:00 EDT
Through an effective quantum field theory including zero temperature Gaussian fluctuations we derive analytical and explicit expressions for the equation of state of three-dimensional ultracold Rabi-coupled two-component bosonic gases with nonuniversal corrections to the interactions. At mean-field level the system presents two ground-states, one symmetric and one non-symmetric or unbalanced. For the symmetric ground state, in the regime where inter-species interactions are weakly attractive and subtly higher than repulsive intra-species, the instability by collapse is avoided by the contribution arising from Gaussian fluctuations, driving thus to formation of a liquidlike phase or droplet phase. This self-bound state is crucially affected by the dependence on the nonuniversal corrections to the interactions, which acts controlling the droplet stability. By tuning the ratio between the inter-species scattering length and the intra-species scattering lengths or the nonuniversal contribution to the interactions we address and establish conditions under which the formation and stability of self-bound Rabi-coupled droplets with nonuniversal corrections to the interactions is favorable.
Quantum Gases (cond-mat.quant-gas)
22 pages
Ann. Phys. 479 (2025) 170071
Mechanochemical feedback drives complex inertial dynamics in active solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Siddhartha Sarkar, Biswarup Ash, Yueyang Wu, Nicholas Boechler, Suraj Shankar, Xiaoming Mao
Active solids combine internal active driving with elasticity to realize states with nonequilibrium mechanics and autonomous motion. They are often studied in overdamped settings, e.g., in soft materials, and the role of inertia is less explored. We construct a model of a chemically active solid that incorporates mechanochemical feedback and show that, when feedback overwhelms mechanical damping, autonomous inertial dynamics can spontaneously emerge through sustained consumption of chemical fuel. By combining numerical simulations, analysis and dynamical systems approaches, we show how active feedback drives complex nonlinear dynamics on multiple time-scales, including limit cycles and chaos. Our results suggest design principles for creating ultrafast actuators and autonomous machines from soft, chemically-powered solids.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Chaotic Dynamics (nlin.CD)
6 pages, 4 figures
Correlations, mean-field limits, and transition to the concentrated regime in motile particle suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Bryce Palmer, Scott Weady, Michael O’Brien, Blakesley Burkhart, Michael J. Shelley
Suspensions of swimming particles exhibit complex collective behaviors driven by hydrodynamic interactions, showing persistent large-scale flows and long-range correlations. While heavily studied, it remains unclear how such structures depend on the system size and swimmer concentration. To address these issues, we simulate very large systems of suspended swimmers across a range of system sizes and volume fractions. For this we use high-performance simulation tools that build on slender body theory and implicit resolution of steric interactions. At low volume fractions and long times, the particle simulations reveal dynamic flow structures and correlation functions that scale with the system size. These results are consistent with a mean-field limit and agree well with a corresponding kinetic theory. At higher concentrations, the system departs from mean-field behavior. Flow structures become cellular, and correlation lengths scale with the particle size. Here, translational motion is suppressed, while rotational dynamics dominate. These findings highlight the limitations of dilute mean-field models and reveal new behaviors in dense active suspensions.
Soft Condensed Matter (cond-mat.soft)
Circuit-level-configurable Zero-field Superconducting Diodes: A Universal Platform Beyond Intrinsic Symmetry Breaking
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-27 20:00 EDT
Xiaofan Shi, Ziwei Dou, Dong Pan, Guoan Li, Yupeng Li, Anqi Wang, Zhiyuan Zhang, Xingchen Guo, Xiao Deng, Bingbing Tong, Zhaozheng Lyu, Peiling Li, Fanming Qu, Guangtong Liu, Jianhua Zhao, Jiangping Hu, Li Lu, Jie Shen
Modern industry seeks next-generation microelectronics with ultra-low dissipation and noise beyond semiconducting systems, where the superconducting electronics offer promise. Its physical foundation is the superconducting diode effect (SDE) with nonreciprocal supercurrent. SDE has hitherto mainly relied on material-specific intrinsic symmetry breaking in superconductors, suffering from low yield, controllability, and compatibility with further functional extension - an undesirable aspect for applications. Here, we demonstrated a field-free SDE due to the chemical potential shift from external circuit line resistance, which is generic and challenges the previous interpretations of the intrinsic symmetry breaking in superconductivity for zero-field SDE. Moreover, this SDE is circuit-level configurable since it can be electrically switched on/off with its polarity and efficiency precisely modulated via gate voltage and circuit reconfiguration, facilitating functional extension. Such a generic, controllable and extensible SDE addresses critical challenges in dissipationless circuit towards application, and thus establishes a robust platform for scalable superconducting electronics.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Quantum spin Hall effects in van der Waals materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Jian Tang, Thomas Siyuan Ding, Chengdong Wang, Ning Mao, Vsevolod Belosevich, Yang Zhang, Xiaofeng Qian, Qiong Ma
The quantum spin Hall (QSH) effect, first predicted in graphene by Kane and Mele in 2004, has emerged as a prototypical platform for exploring spin-orbit coupling, topology, and electronic interactions. Initially realized experimentally in quantum wells exhibiting characteristic QSH signatures, the field has since expanded with the discovery of van der Waals (vdW) materials. This review focuses on vdW systems, which offer unique advantages: their exposed surfaces enable a combination of surface-sensitive spectroscopic and microscopic tools for comprehensive detection of the QSH state; mechanical stacking with other vdW layers facilitates symmetry engineering and proximity effects; and moiré engineering introduces layer skyrmion topological phases and strong correlation effects. We highlight two monolayer families, 1T$ ^\prime$ -MX$ _2$ and MM$ ^\prime$ X$ _4$ , represented by WTe$ _2$ and TaIrTe$ _4$ , respectively. These materials exhibit QSH phases intertwined with or in close proximity to other quantum phases, such as excitonic insulators, charge density waves, and superconductivity. Their low crystal symmetry and topology enable rich quantum geometrical responses, ranging from nonlinear Hall effects to circular photogalvanic effects. We also discuss moiré systems, which combine topology with flatband physics and enhanced correlations, driving spontaneous symmetry breaking and transitions from QSH to quantum anomalous Hall (QAH) states. Remarkably, fractionalized QAH and QSH states have recently been observed in moiré systems, significantly advancing the field of condensed matter physics. Finally, we explore emerging applications of QSH and derived materials, such as using nonlinear Hall effects for quantum rectification in microwave energy harvesting and harnessing fractional anomalous states for topological quantum computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
52 pages; 12 figures; Invited review, comments are welcome
Strain Modulated Catalytic Activity of Pt2XSe3 (X = Hg, Zn) for Hydrogen Evolution Reaction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Caique C. Oliveira, Pedro A. S. Autreto
The catalytic properties of Pt2XSe3 (X = Hg, Zn) in hydrogen-electrode- (HER-) based catalysts have been investigated based on state-of-the-art ab initio simulations. Our results show that the late transition metal sites (Hg and Zn) exhibit the best activity for HER in an acidic environment. Furthermore, lattice stretching and compression can effectively modulate the H binding energy, achieving almost thermoneutral adsorption at 3% compressive strain. The changes are attributed to the modulation in the d-band centers of late transition metal sites, as well as the depletion of charge population on bonding states, contributing to the destabilization of the H-metal bonds. Our contribution explores strain engineering as an effective strategy to tailor the activity of 2D mineral-based catalyst materials for HER, advancing our understanding of how mechanical manipulation can effectively modulate the catalytic properties of these materials.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Submitted to Journal of Materials Chemistry A
Getting out of a tight spot: Cooperative unclogging of hydrogel particles in disordered porous media
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Sanjana Kamath, Laurent Talon, Meera Ramaswamy, Christopher A. Browne, Sujit S. Datta
We use event-driven pore network modeling to study the transport of hydrogel particles through disordered porous media – a process that underlies diverse applications. By simulating particle advection, deformation, and clogging at the pore scale, we identify a dimensionless “squeezing parameter” that quantitatively predicts the depth to which particles penetrate into a given medium across diverse conditions. Our simulations also uncover a surprising cooperative effect: adding more particles enables them to penetrate deeper into the medium. This phenomenon arises because individual particles redirect fluid to adjacent throats, forcing nearby particles through tight pores that they would otherwise clog. Altogether, these results help to establish a quantitative framework that connects microscopic particle mechanics to macroscopic transport behavior.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Pattern Formation and Solitons (nlin.PS)
Generalized many-body exciton g-factors: magnetic hybridization and non-monotonic Rydberg series in monolayer WSe\textsubscript{2}
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Paulo E. Faria Junior, Daniel Hernangómez-Pérez, Tomer Amit, Jaroslav Fabian, Sivan Refaely-Abramson
Magneto-optics of low dimensional semiconductors, such as monolayer transition metal dichalcogenides, offers a vast playground for exploring complex quantum phenomena. However, current \textit{ab initio} approaches fail to capture important experimental observations related to brightening of excitonic levels and their g-factor dependence. Here, we develop a robust and general first principles framework for many-body exciton g-factors by incorporating off-diagonal terms for the spin and orbital angular momenta of single-particle bands and many-body states for magnetic fields pointing in arbitrary spatial directions. We implement our framework using many-body perturbation theory via the GW-Bethe-Salpeter equation (BSE) and supplement our analysis with robust symmetry-based models, establishing a fruitful synergy between many-body GW-BSE and group theory. Focusing on the archetypal monolayer WSe\textsubscript{2}, we accurately reproduce the known results of the low-energy excitons including the Zeeman splitting and the dark/grey exciton brightening. Furthermore, our theory naturally reveals fundamental physical mechanisms of magnetic-field hybridization of higher-energy excitons (s- and p-like) and resolves the long-standing puzzle of the experimentally measured non-monotonic Rydberg series (1s–4s) of exciton g-factors. Our framework offers a comprehensive approach to investigate, rationalize, and predict the non-trivial interplay between magnetic fields, angular momenta, and many-body exciton physics in van der Waals systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Theory of two-component superfluidity of microcavity polaritons
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-27 20:00 EDT
A. Nafis Arafat, Oleg L. Berman, Godfrey Gumbs, Peter B. Littlewood
We investigate Bose-Einstein condensation and two-component superfluidity composed of upper (UP) and lower (LP) polaritons confined to a two-dimensional microcavity. By studying a modified Hamiltonian which incorporates interactions between both polariton branches, we derive the collective excitation spectrum and express the sound velocity as a function of detuning and Rabi splitting. Our analysis reveals that the interplay between effective masses and exciton-photon fractions in the UP and LP branches can significantly enhance the superfluid properties compared to a one-component condensate of only lower polaritons. Specifically, we discover that larger Rabi splitting increases the sound velocity and raises the critical temperature for superfluidity, while negative and positive detuning further favors a two-component condensate. Additionally, we demonstrate that these trends are consistent and applicable to various materials, including GaAs and the transition metal dichalcogenides (TMDCs), thereby indicating the potential for high-temperature superfluid phenomena in two-dimensional polariton systems. We hope these findings will provide a deeper understanding of the physics of structures containing multi-component polariton systems and generate experimental realizations of tunable quantum fluids with light.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
33 pages, 20 figures,
Strong coupling of chiral magnons in altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Zhejunyu Jin, Tianci Gong, Jie Liu, Huanhuan Yang, Zhaozhuo Zeng, Yunshan Cao, Peng Yan
Altermagnets recently are identified as a new class of magnets that break the time-reversal symmetry without exhibiting net magnetization. The role of the dipole-dipole interaction (DDI) on their dynamical properties however is yet to be addressed. In this work, we show that the DDI can induce the strong coupling between exchange magnons with opposite chiralities in altermagnets, manifesting as a significant level repulsion in the magnon spectrum. Crucially, the predicted magnon-magnon coupling is highly anisotropic, and observable in practical experiments. These exotic features are absent in conventional antiferromagnets. Our findings open a new pathway for quantum magnonic information processing based on altermagnetism.
Materials Science (cond-mat.mtrl-sci)
6 pages, 5 figures
Establishment of a compensation rule between the parameters of the Jonschers’s Universal Relaxation Law in disordered materials
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-27 20:00 EDT
Anthony N. Papathanassiou, Elias Sakellis
Experimental results for a huge number of different materials published during the past fifty years confirm the validity of the Jonscher’s Universal Dielectric Response Law. Accordingly,the ac conductivity is a fractional power of frequency. Otemperatures evidence for a proportionality between the logarithm of the pre-exponential factor to the fractional exponent, spectra recorded at different temperatures evidence for a proportionality between the logarithm of the pre-exponential factor to the fractional exponent, as well. The dc conductivity, pre-exponential factor and fractional exponent of the ac conductivity are three state variables, which describe the electric and dielectric properties. These constitute a unique relation by merging the Dielectric Response Law and the Almond - West Scaling Rule, respectively. A partial differentiation chain theorem combined with the temperature dependencies of the dc conductivity, pre-exponential factor and fractional exponent of the ac response, establishes a compensation rule between the parameters of the Universal Dielectric Response Law. The compatibility of the present theorynwth published experimental data is discussed.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Implementing advanced trial wave functions in fermion quantum Monte Carlo via stochastic sampling
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Zhi-Yu Xiao, Zixiang Lu, Yixiao Chen, Tao Xiang, Shiwei Zhang
We introduce an efficient approach to implement correlated many-body trial wave functions in auxiliary-field quantum Monte Carlo (AFQMC). To control the sign/phase problem in AFQMC, a constraint is derived from an exact gauge condition but is typically imposed approximately through a trial wave function or trial density matrix, whose quality can affect the accuracy of the method. Furthermore, the trial wave function can also affect the efficiency through importance sampling. The most natural form of the trial wave function has been single Slater determinants or their linear combinations. More sophisticated forms, for example, with the inclusion of a Jastrow factor or other explicit correlations, have been challenging to use and their implementation is often assumed to require a quantum computer. In this work, we demonstrate that a large class of correlated wave functions, written in the general form of multi-dimensional integrals over hidden or auxiliary variables times Slater determinants, can be implemented as trial wave function by coupling the random walkers to a generalized Metropolis sampling. We discuss the fidelity of AFQMC with stochastically sampled trial wave functions, which are relevant to both quantum and classical algorithms. We illustrate the method and show that an efficient implementation can be achieved which preserves the low-polynomial computational scaling of AFQMC. We test our method in molecules under bond stretching and in transition metal diatomics. Significant improvements are seen in both accuracy and efficiency over typical trial wave functions, and the method yields total ground-state energies systematically within chemical accuracy. The method can be useful for incorporating other advanced wave functions, for example, neural quantum state wave functions optimized from machine learning techniques, or for other forms of fermion quantum Monte Carlo.
Strongly Correlated Electrons (cond-mat.str-el)
Anomalous Transport Gaps of Fractional Quantum Hall Phases in Graphene Landau Levels are Induced by Spin-Valley Entangled Ground States
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Jincheng An, Ajit C. Balram, Udit Khanna, Ganpathy Murthy
We evaluate the transport gaps in the most prominent fractional quantum Hall states in the $ \mathbf{n}{=}0$ and $ \mathbf{n}{=}1$ Landau Levels of graphene, accounting for the Coulomb interaction, lattice-scale anisotropies, and one-body terms. We find that the fractional phases in the $ \mathbf{n}{=}0$ Landau level are bond-ordered, while those in the $ \mathbf{n}{=}1$ Landau level are spin-valley entangled. This resolves a long-standing experimental puzzle [Amet, $ \textit{et al.}$ , Nat. Comm. $ \mathbf{6}$ , 5838 (2015)] of the contrasting Zeeman dependence of the transport gaps in the two Landau levels. The spin-valley entangled phases host gapless Goldstone modes that can be probed via bulk thermal transport measurements. As a byproduct of our computations, we place strong constraints on the values of the microscopic anisotropic couplings such that these are consistent with all known experimental results.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures, and Supplementary Material
High-Entropy Solid Electrolytes Discovery: A Dual-Stage Machine Learning Framework Bridging Atomic Configurations and Ionic Transport Properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Xiao Fu, Jing Xu, Qifan Yang, Xuhe Gong, Jingchen Lian, Liqi Wang, Zibin Wang, Ruijuan Xiao, Hong Li
The rapid development of computational materials science powered by machine learning (ML) is gradually leading to solutions to several previously intractable scientific problems. One of the most prominent is machine learning interatomic potentials (MLIPs), which expedites the study of dynamical methods for large-scale systems. However, a promising field, high-entropy (HE) solid-state electrolytes (SEs) remain constrained by trial-and-error paradigms, lacking systematic computational strategies to address their huge and high-dimensional composition space. In this work, we establish a dual-stage ML framework that combines fine-tuned MLIPs with interpretable feature-property mapping to accelerate the high-entropy SEs discovery. Using Li$ _3$ Zr$ _2$ Si$ _2$ PO$ _{12}$ (LZSP) as a prototype, the fine-tuned CHGNet-based relaxation provides atomic structure for each configuration, the structure features - mean squared displacement (SF-MSD) model predicts the ionic transport properties and identifies critical descriptors. The theoretical studies indicate that the framework can satisfy the multiple requirements including computational efficiency, generalization reliability and prediction accuracy. One of the most promising element combinations in the quinary HE-LZSP space containing 4575 compositions is identified with a high ionic conductivity of 4.53 mS/cm as an application example. The framework contains generalizability and extensibility to other SE families.
Materials Science (cond-mat.mtrl-sci)
Signatures of edge states in antiferromagnetic van der Waals Josephson junctions
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-27 20:00 EDT
Celia González-Sánchez, Ignacio Sardinero, Jorge Cuadra, Alfredo Spuri, José A. Moreno, Hermann Suderow, Elke Scheer, Pablo Burset, Angelo Di Bernardo, Rubén Seoane Souto, Eduardo J. H. Lee
The combination of superconductivity and magnetic textures represents a promising approach to explore unconventional superconducting phenomena, including new correlated and topological phases. Van der Waals (vdW) materials have emerged in this context as a versatile platform to explore the interplay between these two competing orders. Here, we report on individual NbSe2/NiPS3/NbSe2 vdW Josephson junctions behaving as superconducting quantum interference devices (SQUIDs), which we attribute to the interplay between the superconductivity of NbSe2 and the spin texture of the vdW antiferromagnetic insulator NiPS3. The SQUID behavior, which persists for in-plane magnetic fields of at least 6 T, is the result of interference between localized transport channels that form in two separate regions of the sample. Microscopic modeling of the antiferromagnet insulator/superconductor (AFI/S) interface reveals the formation of localized states at the edges of the junction that can lead to localized channels that dominate the transport. Our findings highlight the potential of vdW superconducting heterostructures with AFs as platforms for engineering and probing novel superconducting phenomena, and they establish a new route for lithographic-free SQUIDs that operate in high magnetic fields.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 4 figures. Supplemental Material in anc folder
Ligand-SOC enhanced $4f^5$ Kitaev antiferromagnet: Application to $\mathrm{SmI}_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Li-Hao Xia, Yi-Peng Gao, Zhao-Yang Dong, Jian-Xin Li
The search for Kitaev quantum spin liquids (Kitaev-QSLs) in real materials has mainly focused on $ 4d$ - and $ 5d$ -electron honeycomb systems. A recent experimental study on the $ 4f^5$ honeycomb iodide $ \mathrm{SmI}_3$ reported the absence of long-range magnetic order down to $ 0.1\ \text{K}$ , suggesting a possible Kitaev-QSL phase. Motivated by the interplay between the complex exchange processes inherent to the $ 4f^5$ multi-electron configuration and the strong spin-orbit coupling (SOC) of the iodine ligands, we systematically investigate the effective exchange interactions in $ \mathrm{SmI}_3$ using the strong coupling expansion method. Our findings reveal that bond-dependent SOCs (bond-SOCs), extracted from relativistic density functional theory (DFT) calculations, significantly enhance the antiferromagnetic (AFM) Kitaev interaction, driving the system close to the AFM Kitaev point. A microscopic analysis based on the Slater-Koster approach further indicates that the strong SOC of the iodine ligands (ligand-SOC) is the origin of bond-SOCs and plays a pivotal role in mediating the superexchange processes. Additionally, we identify a spin-flop transition induced by the bond-SOCs, where the enhanced AFM Kitaev interactions shift the AFM order from the out-of-plane $ [1, 1, 1]$ -direction to an in-plane orientation, breaking the $ C_3$ rotational symmetry. Linear spin-wave theory (LSWT) further predicts the emergence of gapless modes following the spin-flop transition, indicating enhanced fluctuations and increased instability near the AFM Kitaev point. Our results highlight the crucial role of strong ligand-SOC in stabilizing the dominant AFM Kitaev interactions in $ \mathrm{SmI}_3$ and provide valuable insights for discovering new $ f$ -electron Kitaev-QSL candidates.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
16 pages, 10 figures
AI-predicted PT-symmetric magnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Parity-time-reversal-symmetric odd-parity antiferromagnetic (AFM1) materials are of interest for their symmetry-enabled quantum transport and optical effects. These materials host odd-parity terms in their band dispersion, leading to asymmetric energy bands and enabling responses such as the magnetopiezoelectric effect, nonreciprocal conductivity, and photocurrent generation. In addition, they may support a nonlinear spin Hall effect without spin-orbit coupling, offering an efficient route to spin current generation. We identify 23 candidate AFM1 materials by combining artificial intelligence, density functional theory (DFT), and symmetry analysis. Using a graph neural network model and incorporating AFM1-specific symmetry constraints, we screen Materials Project compounds for high-probability AFM1 candidates. DFT calculations show that AFM1 has the lowest energy among the tested magnetic configurations in 23 candidate materials. These include 3 experimentally verified AFM1 materials, 10 synthesized compounds with unknown magnetic structures, and 10 that are not yet synthesized.
Materials Science (cond-mat.mtrl-sci)
Coupling an elastic string to an active bath: the emergence of inverse damping
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
Aaron Beyen, Christian Maes, Ji-Hui Pei
We consider a slow elastic string with Klein-Gordon dynamics coupled to a bath of run-and-tumble particles. We derive and solve the induced Langevin-Klein-Gordon string dynamics with explicit expressions for the streaming term, friction coefficient, and noise variance. These parameters are computed exactly in a weak coupling expansion. The induced friction is a sum of two terms: one entropic, proportional to the noise variance as in the Einstein relation for a thermal equilibrium bath, and a frenetic contribution that can take both signs. The frenetic part wins for higher bath persistence, making the total friction negative, and hence creating a wave instability akin to inverse Landau damping; the wave acceleration decreases again when the propulsion speed of the active particles gets too high.
Statistical Mechanics (cond-mat.stat-mech)
Unraveled origin of the multi-directional and super wide optical-response found on metal/n-Si
New Submission | Other Condensed Matter (cond-mat.other) | 2025-05-27 20:00 EDT
Takanari Yasuia, Kazuya Nakayama
The optical responses for UV to NIR and muti-directional photo current have been found on Au (metal) on n-Si device. The unique phenomena have been unresolved since the first sample fabricated in 2007. The self organized sub-micron metal with various crystal faces was supposed to activate as an optical wave guide into Si surface. This, however, is insufficient to explain the unique features above. Thus, for more deep analysis, returning to consider the Si-band structure, indirect/direct transitions of inter conduction bands: X-W, X-K and {\Gamma}-L in the 1st Brillouin Zone/Van Hove singularity at L point, synchronizing with scattering, successfully give these characteristics a reasonable explanation. The calculation of the quantum efficiency between X-W and X-K agreed with those sensitivity for visible region (1.1 to 2.0 eV), the doping process well simulates it for NIR (0.6 to 1.0 eV). Doping electrons (~10^18/cm3) are filled up the zero-gap at around X of a reciprocal lattice point. This is why a lower limit of 0.6 eV was arisen in the sensitivity measurement. When the carrier scattering model was applied to the inter band (X-W, X-K and {\Gamma}-L) transitions, the reasonable interpretation was obtained for the directional dependence of photo-currents with UV (3.4 eV) and Visible (3.1 and 1.9 eV) excitation. Band to band scatterings assist to extend the available optical range and increase variety of directional responses. Utilizing this principle for some indirect transition semiconductors, it will be able to open the new frontier in photo-conversion system, where it will be released from those band gaps and directivity limitations.
Other Condensed Matter (cond-mat.other)
23 pages, 19 figures
Ubiquity of rotational symmetry breaking in superconducting films, from Fe(Te,Se)/Bi$_2$Te$_3$ to Nb, and the effect of measurement geometry
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-27 20:00 EDT
Debarghya Mallick, Hee Taek Yi, Xiaoyu Yuan, Seongshik Oh
FeTe$ _{0.5}$ Se$ _{0.5}$ /Bi$ _2$ Te$ _3$ heterostructure is a promising new platform in the journey toward topological quantum computation, considering that first, FeTe$ _{0.5}$ Se$ _{0.5}$ is itself known to be a topological superconductor (TSC) and second, the heterostructure has topological interface states that can be proximitized into TSC even if FTS fails to become TSC on its own. Here, we show that this system exhibits quasi-2D superconductivity, and utilizing the standard in-plane magneto-transport measurements, we discover two-fold anisotropy (a.k.a nematicity) in R$ _{xx}$ and I$ _c$ measurement, even though the system exhibits globally 12-fold symmetry. Then, we carried out similar measurements on a polycrystalline niobium (Nb) thin film, a well-known s-wave elemental superconductor, and found a similar two-fold symmetry even for this Nb system. This implies either that nematic behavior is ubiquitous or that the in-plane magneto-transport measurement scheme routinely used to detect nematicity is not a reliable method to probe nematicity. We show that the angle-dependent response of vortices in the superconducting regime to the magnetic Lorentz force is very likely the main cause behind the ubiquitous nematic behaviors of this measurement scheme. In other words, this measurement scheme is intrinsically two-fold, and is therefore not suitable to detect the nematicity. Accordingly, all the previous reports of nematicity based on similar measurement practices, reported on various samples, including thin films, bulk crystals, and exfoliated flakes, need to be reinterpreted.
Superconductivity (cond-mat.supr-con)
Statistical Mechanics and Categorical Entropy
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
This paper investigates the relationship between categorical entropy and von Neumann entropy of quantum lattices. We begin by studying the von Neumann entropy, proving that the average von Neumann entropy per site converges to the logarithm of an algebraic integer in the low-temperature and thermodynamic limits. Next, we turn to categorical entropy. Given an endofunctor of a saturated A-infinity-category, we construct a corresponding lattice model, through which the categorical entropy can be understood in terms of the information encoded in the model. Finally, by introducing a gauged lattice framework, we unify these two notions of entropy. This unification leads naturally to a sufficient condition for a conjectural algebraicity property of categorical entropy, suggesting a deeper structural connection between A-infinity-categories and statistical mechanics.
Statistical Mechanics (cond-mat.stat-mech), Category Theory (math.CT)
Spinodal and Equilibrium Global Phase Diagram of the d=3 Merged Potts-Cubic-Clock Model: First-Order Equilibrium and Second-Order Spinodal Boundaries with Hidden Topologies from Renormalization-Group Theory
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
A model that merges the Potts, cubic, and clock models is studied in spatial dimension d=3 by renormalization-group theory. Effective vacancies are included in the renormalization-group initial conditions. In the global phase diagram, 5 different ordered phases, namely ferromagnetic, antiferromagnetic, ferrimagnetic, antiferrimagnetic, axial, and a disordered phase are found, separated by first- and second-order phase boundaries. 8 different phase diagram cross-sections occur. When the effective vacancies are suppressed, the global spinodal phase diagram is found: All disordering phase transitions become second order, the disordered phase recedes, and 17 different phase diagram cross-sections occur, spinodality thus much enriching ordering behavior. In the spinodal phase diagram, the ferrimagnetic and antiferrimagnetic phases have reentrance. The employed renormalization group transformation is exact on the d=3 dimensional hierarchical model and Migdal-Kadanoff approximate on the cubic lattice.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 5 figures, 45 phase diagrams, 2 Tables
Self-patterning of Liquid Field’s Metal for Enhanced Performance of Two-dimensional Semiconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Kwanghee Han, Heeyeon Lee, Minseong Kwon, Vinod Menon, Chaun Jang, Young Duck Kim
Two-dimensional (2D) van der Waals semiconductors show promise for atomically thin flexible and transparent optoelectronic devices in future this http URL, developing high-performance field-effect transistors (FETs) based on 2D materials is impeded by two key challenges, the high contact resistance at the 2D semiconductors-metal interface and the limited effective doping strategies. Here, we present a novel approach to overcome these challenges using self-propagating liquid Fields metal, a eutectic alloy with a low melting point of approximately 62 C. By modifying pre-patterned electrodes on WSe2 FETs through the deposition of Fields metal onto contact pad edges followed by vacuum annealing, we create new semimetal electrodes that seamlessly incorporate the liquid metal into 2D semiconductors. This integration preserves the original electrode architecture while transforming to semimetal compositions of Fields metal such as Bi, In, and Sn modifies the work functions to 2D semiconductors, resulting in reduced contact resistance without inducing Fermi-level pinning and charge carrier mobilities. Our method enhances the electrical performance of 2D devices and opens new avenues for designing high-resolution liquid metal circuits suitable for stretchable, flexible, and wearable 2D semiconductor applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
17 pages, 4 figures
Supervised and Unsupervised protocols for hetero-associative neural networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-27 20:00 EDT
Andrea Alessandrelli, Adriano Barra, Andrea Ladiana, Andrea Lepre, Federico Ricci-Tersenghi
This paper introduces a learning framework for Three-Directional Associative Memory (TAM) models, extending the classical Hebbian paradigm to both supervised and unsupervised protocols within an hetero-associative setting. These neural networks consist of three interconnected layers of binary neurons interacting via generalized Hebbian synaptic couplings that allow learning, storage and retrieval of structured triplets of patterns. By relying upon glassy statistical mechanical techniques (mainly replica theory and Guerra interpolation), we analyze the emergent computational properties of these networks, at work with random (Rademacher) datasets and at the replica-symmetric level of description: we obtain a set of self-consistency equations for the order parameters that quantify the critical dataset sizes (i.e. their thresholds for learning) and describe the retrieval performance of these networks, highlighting the differences between supervised and unsupervised protocols. Numerical simulations validate our theoretical findings and demonstrate the robustness of the captured picture about TAMs also at work with structured datasets. In particular, this study provides insights into the cooperative interplay of layers, beyond that of the neurons within the layers, with potential implications for optimal design of artificial neural network architectures.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (stat.ML)
55 pages, 11 figures
Cooperative ligand-mediated transitions in simple macromolecules
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
James L. Martin Robinson, Neshat Moslehi, Nikolaos Dramountanis, Lennart van den Hoven, Alexander M. van Silfhout, Kanvaly S. Lacina, Mies van Steenbergen, Wessel Custers, Bas G. P. van Ravensteijn, Willem K. Kegel
In biology, ligand mediated transitions (LMT), where the binding of a molecular ligand onto the binding site of a receptor molecule leads to a well-defined change in the conformation of the receptor, are often referred to as ‘the second secret of life’. Sharp, cooperative transitions arise in many biological cases, while examples of synthetic cooperative systems are rare. This is because well-defined conformational states are hard to ‘program’ into a molecular design. Here, we impose an external constraint in the form of two immiscible liquids that effectively define and limit the available conformational states of two different synthetic and relatively simple macromolecules. We show that the mechanism of the observed cooperative transitions with ligand concentration is the coupling of ligand binding and conformation, similar to more complex biological systems. The systems studied are: (1) Hydrophobic polyelectrolytes (HPE), which are (bio) polymers that consist of hydrophobic as well as ionizable (proton and hydroxyl ligand-binding) functional groups. (2) Oligomeric metal chelators (OMC), which are oligomers composed of metal ion chelating repeating groups that are able to bind metal ions (considered as the ‘ligands’), resulting in gel-like networks of oligomers crosslinked by coordinated metal ions. We find that in HPE, interactions between ligands and individual macromolecules explain the observed cooperative transitions. For OMC, coordinated bonds significantly enhance the degree of cooperativity, compared to HPE.
Soft Condensed Matter (cond-mat.soft)
Temperature- and charge carrier density-dependent electronic response in methylammonium lead iodide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Jiacheng Wang Jungmin Park, Lei Gao, Lucia Di Virgilio, Sheng Qu, Heejae Kim, Hai I. Wang, Li-Lin Wu, Wen Zeng, Mischa Bonn, Zefeng Ren, Jaco J. Geuchies
Understanding carrier dynamics in photoexcited metal-halide perovskites is key for optoelectronic devices such as solar cells (low carrier densities) and lasers (high carrier densities). Trapping processes at low carrier densities and many-body recombination at high densities can significantly alter the dynamics of photoexcited carriers. Combining optical-pump/THz probe and transient absorption spectroscopy we examine carrier responses over a wide density range (10^14-10^19 cm-3) and temperatures (78-315K) in the prototypical methylammonium lead iodide perovskite. At densities below ~10^15 cm-3 (room temperature, sunlight conditions), fast carrier trapping at shallow trap states occurs within a few picoseconds. As excited carrier densities increase, trapping saturates, and the carrier response stabilizes, lasting up to hundreds of picoseconds at densities around ~10^17 cm-3. Above 10^18 cm-3 a Mott transition sets in: overlapping polaron wavefunctions lead to ultrafast annihilation through an Auger recombination process occurring over a few picoseconds. We map out trap-dominated, direct recombination-dominated, and Mott-dominated density regimes from 78-315 K, ultimately enabling the construction of an electronic phase diagram. These findings clarify carrier behavior across operational conditions, aiding material optimization for optoelectronics operating in the low (e.g. photovoltaics) and high (e.g. laser) carrier density regimes.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
22 pages, 17 figures
Magnetic Anisotropy and Absence of Long-Range Order in the Triangular Magnet NdMgAl${11}$O${19}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Sonu Kumar, Jan Prokleška, Karol Załęski, Andrej Kancko, Cinthia Correa, Małgorzata Śliwińska-Bartkowiak, Gaël Bastien, Ross H. Colman
The rare-earth triangular-lattice magnet NdMgAl11O19 offers an ideal platform for examining the interplay of crystal electric field effects, geometric frustration, and weak exchange interactions. Using high-quality single crystals, we measured magnetic susceptibility and magnetization down to 1.8 K, while specific heat was measured down to 45 mK. The system exhibits uniaxial anisotropy along the c-axis, with a ground-state Kramers doublet. A Curie-Weiss temperature of -0.38 K indicates weak antiferromagnetic interactions, while a specific heat anomaly at 81 mK suggests weak magnetic correlations with no long-range magnetic order. The absence of long-range magnetic order down to 45 mK makes it a very interesting material, which is highly frustrated but weakly correlated. Under external fields, the Zeeman splitting of the ground-state doublet leads to a field-tunable Schottky anomaly, with the specific heat peak shifting to 0.65 meV at 3 T, with g ~ 3.7. A Brillouin function fit to magnetization yields g ~ 3.72, confirming the quasi-paramagnetic nature of NdMgAl11O19. These findings highlight NdMgAl11O19 as a promising candidate to investigate quantum spin liquid and exotic spin states in frustrated triangular magnets.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Uncovering relationships between the electronic self-energy and coupled-cluster doubles theory
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
We derive the coupled-cluster doubles (CCD) amplitude equations by introduction of the particle-hole-time decoupled electronic self-energy. This leads to an alternative ground state correlation energy obtained from the Green’s function formalism which is exactly of the form obtained in coupled-cluster doubles theory. We demonstrate the relationship to the ionization potential/electron affinity equation-of-motion coupled-cluster doubles (IP/EA-EOM-CCD) eigenvalue problem by coupling the reverse-time self-energy contributions while maintaining particle-hole separability. The formal relationships established are demonstrated by exact solution of the Hubbard dimer.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Ab Initio Prediction of Large Thermoelectric Effect in Distorted Heusler Alloy Ti-Fe-Sb Compound
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Rifky Syariati, Athorn Vora-ud, Fumiyuki Ishii, Tosawat Seetawan
The thermoelectric figure of merit of the Heusler alloy TiFe$ _{1.5}$ Sb was investigated by first-principles calculations of lattice thermal conductivity. The electronic thermal conductivity, electrical conductivity, and Seebeck coefficient are calculated by semi-classical Boltzmann transport theory. TiFe$ _{1.5}$ Sb was found to be thermally and dynamically stable, as confirmed by its phonon dispersion. Additionally, the small phonon band gap between acoustic and optical modes enhances phonon scattering, leading to a low lattice thermal conductivity of 0.703 W/mK at 300 K. Our study also reveals that TiFe$ _{1.5}$ Sb is a non-magnetic semiconductor. Notably, it demonstrates a significant longitudinal thermoelectric effect, with a Seebeck coefficient of 359.4 $ \mu$ V/K at 300 K. The combination of low lattice thermal conductivity and a high Seebeck coefficient results in a high thermoelectric figure of merit (ZT) of 0.88 and 0.91 at 300 K and 500 K, respectively. These findings highlight the considerable potential of TiFe$ _{1.5}$ Sb as a promising material for thermoelectric device applications.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
17 pages, 5 figures,
First principles investigation of zb-TiSn: A promising narrow bandgap semiconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Sudeep R, Sarojini M, Uma Mahendra Kumar Koppolu
We have investigated the structural stability of a binary compound TiSn in the zincblende symmetry. The phonon dispersion studies confirms that, TiSn with a nominal composition of 1:1 can exist in zincblende form. No imaginary frequencies are observed indicating the stable bonding nature of Ti-Sn. From the First principles calculations based on density functional theory, the resulting electronic band structure had revealed that zb-TiSn, is a narrow band gap semiconductor with an energy gap of 0.3 eV with GGA- PBE. The bonding nature is identified as polar covalent, determined from charge density difference plots and Bader charge analysis. Further more, the linear optical properties of zb-TiSn are derived from the Khon-Sham eigenvalues.
Materials Science (cond-mat.mtrl-sci)
Dirac fermions on a surface with localized strain
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Samuel B. B. Almeida, J. E. G. Silva, C. A. S. Almeida
We study the influence of a localized Gaussian deformation on massless Dirac fermions confined to a two-dimensional curved surface. Both in-plane and out-of-plane displacements are considered within the framework of elasticity theory. These deformations couple to the Dirac spinors via the spin connection and the vielbeins, leading to a position-dependent Fermi velocity and an effective geometric potential. We show that the spin connection contributes an attractive potential centered on the deformation and explore how this influences the fermionic density of states. Analytical and numerical solutions reveal the emergence of bound states near the deformation and demonstrate how the Lamé coefficients affect curvature and state localization. Upon introducing an external magnetic field, the effective potential becomes confining at large distances, producing localized Landau levels that concentrate near the deformation. A geometric Aharonov-Bohm phase is identified through the spinor holonomy. These results contribute to the understanding of strain-induced electronic effects in Dirac materials, such as graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
23 pages, 17 captioned figures
G-type Antiferromagnetic BiFeO$_3$ is a Multiferroic $g$-wave Altermagnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Andrea Urru, Daniel Seleznev, Yujia Teng, Se Young Park, Sebastian E. Reyes-Lillo, Karin M. Rabe
G-type antiferromagnetic BiFeO$ _3$ is shown to be an altermagnet. We present the band structure using an unconventional scheme designed to highlight the distinctive spin splitting which is characteristic of altermagnets. We define and show plots of the spin-splitting function in reciprocal space. We show that the nodal surfaces of the spin-splitting function that follow from symmetry can be classified into two types, which we call symmetry-enforced and continuity-enforced. We describe the spin-splitting function with a simple parametrization in a basis of symmetry-adapted plane waves. Using group-theory analysis based on irreducible representations of the crystallographic Laue group, we confirm that the altermagnetism of G-type BiFeO$ _3$ is $ g$ -wave and present a complete classification table for the general three-dimensional case. Finally, we discuss the effect of ferroelectric switching on the altermagnetic order, and identify three classes of ferroelectric altermagnets.
Materials Science (cond-mat.mtrl-sci)
Dynamics of Poro-viscoelastic Wetting with Large Swelling
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
B. X. Zheng, T. S. Chan, E. H. van Brummelen, J. H. Snoeijer
The deposition of droplets onto a swollen polymer network induces the formation of a wetting ridge at the contact line. Current models typically consider either viscoelastic effects or poroelastic effects, while polymeric gels often exhibit both properties. In this study, we investigate the growth of the wetting ridge using a comprehensive large deformation theory that integrates both dissipative mechanisms - viscoelasticity and poroelasticity. In the purely poroelastic case, following an initial instantaneous incompressible deformation, the growth dynamics exhibit scale-free behavior, independent of the elastocapillary length or system size. A boundary layer of solvent imbibition between the solid surface (in contact with the reservoir) and the region of minimal chemical potential is created. At later times, the ridge equilibrates on the diffusion timescale given by the elastocapillary length. When viscoelastic properties are incorporated, our findings show that, during the early stages (prior to the viscoelastic relaxation timescale), viscoelastic effects dominate the growth dynamics of the ridge and solvent transport is significantly suppressed. Beyond the relaxation time, the late-time dynamics closely resemble those of the purely poroelastic case. These findings are discussed in light of recent experiments, showing how our approach offers a new interpretation framework for wetting of polymer networks of increasing complexity.
Soft Condensed Matter (cond-mat.soft)
Room-temperature spin-lifetime anisotropy exceeding 60 in bilayer graphene spin valves proximity coupled to WSe$_2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Timo Bisswanger, Anne Schmidt, Frank Volmer, Christoph Stampfer, Bernd Beschoten
A spin lifetime anisotropy between in-plane and out-of-plane spins in bilayer graphene (BLG) can be achieved by spin-orbit proximity coupling of graphene to transition metal dichalcogenides. This coupling reduces the in-plane spin lifetime due to proximity-induced spin scattering, while the out-of-plane spin lifetime remains largely unaffected. We show that at room temperature spin lifetime anisotropy exceeds 60 in a bilayer graphene lateral spin valve proximity coupled to WSe$ _2$ . The out-of-plane spin lifetime of about 250 ps closely matches that of a BLG reference region not in contact with WSe$ _2$ . In contrast, the estimated in-plane spin lifetime of less than 4 ps leads to a complete suppression of the in-plane spin signal at the ferromagnetic Co/MgO spin detector. The proximity coupling of WSe$ _2$ to BLG is particularly promising, as it does not compromise the charge carrier mobility within the graphene channel.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
A high-efficiency neuroevolution potential for tobermorite and calcium silicate hydrate systems with ab initio accuracy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Xiao Xu, Shijie Wang, Haifeng Qin, Zhiqiang Zhao, Zheyong Fan, Zhuhua Zhang, Hang Yin
Tobermorite and Calcium Silicate Hydrate (C-S-H) systems are indispensable cement materials but still lack a satisfactory interatomic potential with both high accuracy and high computational efficiency for better understanding their mechanical performance. Here, we develop a Neuroevolution Machine Learning Potential (NEP) with Ziegler-Biersack-Littmark hybrid framework for tobermorite and C-S-H systems, which conveys unprecedented efficiency in molecular dynamics simulations with substantially reduced training datasets. Our NEP model achieves prediction accuracy comparable to DFT calculations using just around 300 training structures, significantly fewer than other existing machine learning potentials trained for tobermorite. Critically, the GPU-accelerated NEP computations enable scalable simulations of large tobermorite systems, reaching several thousand atoms per GPU card with high efficiency. We demonstrate the NEP’s versatility by accurately predicting mechanical properties, phonon density of states, and thermal conductivity of tobermorite. Furthermore, we extend the NEP application to large-scale simulations of amorphous C-S-H, highlighting its potential for comprehensive analysis of structural and mechanical behaviors under various realistic conditions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Strain-induced magnetic damping anomaly in La${1-x}$Sr${x}$MnO$_{3}$ ($x=0.3$-$0.5$) thin films
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Ryotaro Arakawa, Sachio Komori, Tomoyasu Taniyama
Magnetic properties of La$ _{1-x}$ Sr$ _x$ MnO$ _{3}$ (LSMO) are highly sensitive to various factors such as the Sr doping level $ x$ , lattice strain, and oxygen stoichiometry due to the strongly correlated nature of $ 3d$ electrons. For the development of energy-efficient spintronic devices with ultra-low magnetic damping of LSMO, a thorough understanding of its complex magnetization dynamics is of great importance. In this work, we have measured ferromagnetic resonance of LSMO thin films on Nb-doped SrTiO$ _3$ (Nb-STO) substrates over a wide temperature and frequency range and observed an anomalous increase in the Gilbert damping constant and a decrease in the effective saturation magnetization at temperatures below 100 K. The anomalies become more pronounced as the LSMO thickness decreases while they are not observed for LSMO on (LaAlO$ _3$ )$ _{0.3}$ (Sr$ _2$ TaAlO$ _6$ )$ _{0.7}$ substrates with relatively small epitaxial strain. The results suggest that the epitaxial strain-induced magnetically dead layer at the LSMO/Nb-STO interface acts as a spin sink and leads to the anomalies in the magnetization dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 8 figures
Fermi-liquid transport beyond the upper critical field in superconducting La$_2$PrNi$_2$O$_7$ thin films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-27 20:00 EDT
Yu-Te Hsu, Yidi Liu, Yoshimitsu Kohama, Tommy Kotte, Vikash Sharma, Yaoju Tarn, Yijun Yu, Harold Y. Hwang
Unconventional superconductivity typically emerges out of a strongly correlated normal state, manifesting as a Fermi liquid with highly enhanced effective mass or a strange metal with $ T$ -linear resistivity in the zero-temperature limit. In Ruddlesden-Popper bilayer nickelates $ R_3$ Ni$ 2$ O$ 7$ , superconductivity with a critical temperature ($ T{\rm c}$ ) exceeding 80 and 40 K has been respectively realised in bulk crystals under high pressure and thin films under compressive strain. These advancements create new materials platforms to study the nature of high-$ T{\rm c}$ superconductivity, calling for the characterisation of fundamental normal-state and superconducting parameters therein. Here we report detailed magnetotransport experiments on superconducting La$ _2$ PrNi$ 2$ O$ 7$ (LPNO) thin films under pulsed magnetic fields up to 64 T and access the normal-state behaviour over a wide temperature range between 1.5 and 300 K. We find that the normal state of LPNO exhibits the hallmarks of Fermi liquid transport, including $ T^2$ temperature dependence of resistivity and Hall angle, and $ H^2$ magnetoresistance obeying Kohler scaling. Using the empirical Kadowaki-Woods ratio relating the transport coefficient and electronic specific heat, we estimate a quasiparticle effective mass $ m^\ast/m_e \simeq 10$ in PLNO, thereby revealing the highly renormalized Fermi liquid state which hosts the high-temperature nickelate superconductivity. Our results demonstrate that LPNO follows the same $ T{\rm c}/T{\rm F}^\ast$ scaling observed across a wide variety of strongly correlated superconductors and provide crucial constraints for a viable model for superconductivity in bilayer nickelates.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Bayesian sparse modeling for interpretable prediction of hydroxide ion conductivity in anion-conductive polymer membranes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Ryo Murakami, Kenji Miyatake, Ahmed Mohamed Ahmed Mahmoud, Hideki Yoshikawa, Kenji Nagata
Anion-conductive polymer membranes have attracted considerable attention as solid electrolytes for alkaline fuel cells and electrolysis cells. Their hydroxide ion conductivity varies depending on factors such as the type and distribution of quaternary ammonium groups, as well as the structure and connectivity of hydrophilic and hydrophobic domains. In particular, the size and connectivity of hydrophilic domains significantly influence the mobility of hydroxide ions; however, this relationship has remained largely qualitative. In this study, we calculated the number of key constituent elements in the hydrophilic and hydrophobic units based on the copolymer composition, and investigated their relationship with hydroxide ion conductivity by using Bayesian sparse modeling. As a result, we successfully identified composition-derived features that are critical for accurately predicting hydroxide ion conductivity.
Soft Condensed Matter (cond-mat.soft), Applications (stat.AP), Machine Learning (stat.ML)
Thermoelectric performance of Ni-Au metallic alloys determined by resonant scattering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Kacper Pryga, Bartlomiej Wiendlocha
This work presents a theoretical study of the electronic structure and transport properties of Ni-Au alloys, recently identified as excellent thermoelectric metals with a power factor significantly exceeding that of conventional semiconductor thermoelectrics. Using first-principles calculations based on the Korringa-Kohn-Rostoker method combined with the coherent-potential approximation (KKR-CPA) and the Kubo-Greenwood formalism, we demonstrate the key role of resonant scattering in determining the thermoelectric properties of these alloys. This is supported by calculated densities of states, Bloch spectral functions, electrical conductivity, and thermopower. Alloying Ni with Au not only induces resonant scattering but also leads to the formation of a flat band below the Fermi level. The combination of these two features results in high thermopower, arising from a transition between resonant and weak scattering regimes near the Fermi level. Our findings are further compared with analogous calculations for constantan, a Ni-Cu alloy long regarded as a reference thermoelectric metal. We show that differences between the Ni-Au and Ni-Cu systems explain why Ni-Au exhibits nearly twice the thermopower of Ni-Cu. Finally, we simulate the effect of lattice parameter variation on the thermoelectric performance of Ni-Au and suggest that this is a promising pathway for further enhancement, for example through additional alloying or layer deposition.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
13 pages, 11 figures + supplemental material
Coherence, Transport, and Chaos in 1D Bose-Hubbard Model: Disorder vs. Stark Potential
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-27 20:00 EDT
Asad Ali, M.I. Hussain, Saif Al-Kuwari, M. T. Rahim, H. Kuniyil, Seyed Mohammad Hosseiny, Jamileh Seyed-Yazdi, Hamid Arian Zad, Saeed Haddadi
We study quantum coherence and phase transitions in a finite-size one-dimensional Bose-Hubbard model using exact numerical diagonalization. The system is investigated under the competing effects of thermal fluctuations, a Stark potential, and a disorder term. We compute several observables, including the condensate fraction, superfluid fraction, visibility, number fluctuations, and the $ \ell_1$ -norm of quantum coherence, to characterize the transition from the Mott insulator to the superfluid phase. In the standard Bose-Hubbard model, ground-state properties exhibit signatures of a quantum phase transition under open boundary conditions. While finite-size effects preclude an exact realization of the thermodynamic transition, our findings serve as indicators of the underlying quantum critical behavior of the disordered Bose-Hubbard model. At finite temperatures, this critical point shifts to a smooth crossover, reflecting the suppression of long-range coherence typical of larger systems. A nonzero Stark potential delays this crossover, promoting localization and the formation of non-superfluid condensates. In contrast, thermal fluctuations can induce unexpected coherence through fluctuation-driven tunneling. Disorder disrupts superfluidity but preserves local coherence, with thermal states exhibiting an enhanced $ \ell_1$ -norm of coherence within the Bose glass regime. Our results highlight how disorder, tilt, and temperature jointly reshape the coherence landscape, and offer valuable insights for quantum simulation and the characterization of quantum phases in strongly correlated systems. Non-ergodic behavior is observed in the clean system where the mean gap ratio stays below Poisson and Gaussian orthogonal ensemble (GOE) values. With a Stark potential, level statistics shift from Poisson-like to near-GOE as tunneling increases, which indicates a crossover to semi-ergodic dynamics.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
14 pages, 16 figures
Tunable Fujita-Miyazawa-Type Three-Body Force in Ultracold Atoms
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-27 20:00 EDT
Hiroyuki Tajima, Eiji Nakano, Kei Iida
We show how a Fujita-Miyazawa-type three-body force emerges among three impurity atoms immersed in an atomic Bose-Einstein condensate near an interspecies Feshbach resonance. As a result of thermal average over excitations in the medium and impurities as well as expansion with respect to the impurity-medium and Feshbach resonance couplings, two superfluid phonons and a closed channel resonance play a role in producing an effective three-body force, as in the original three-nucleon case in which two pions and a $ \Delta$ resonance are involved. The proposed Fujita-Miyazawa-type three-body force can be enhanced by tuning the closed-channel energy level via an external magnetic field, and moreover, its strength can be confirmed experimentally by measuring the impurity equation of state. Our result gives a new insight into an analogy between atomic polarons and nuclear few-body systems.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
6 pages, 4 figures
Attraction-Induced Cluster Fragmentation and Local Alignment in Active Particle Systems
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Sota Shimamura, Nen Saito, Shuji Ishihara
We numerically studied active Brownian particles with attractive interactions. Contrary to our intuition, the attractive force between particles disrupts the formation of a single cluster observed in motility-induced phase separation, giving rise to a multi-cluster state characterized by a power-law distribution of cluster sizes. Remarkably, the self-propulsion directions spontaneously align within each cluster, resulting in enhanced cluster motility despite the absence of alignment interactions. This study revealed the intricate role of attractive interactions in the aggregation of motile systems.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
6 pages, 3 figures
Active Matter under Cyclic Stretch: Modeling Microtubule Alignment and Bundling
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Takumi Tagaki, Seiya Nishikawa, Shuji Ishihara
We investigate the behavior of self-propelled particles under cyclic stretching, inspired by the characteristic pattern dynamics observed in microtubule (MT) motility assays subjected to uniaxial cyclic substrate stretching. We develop a self-propelled particle model that incorporates the elastic energy acting on the filaments due to substrate deformation, successfully reproducing the experimentally observed MT patterns. Additionally, the general framework of the model enables systematic exploration of collective responses to various substrate deformations, offering potential applications in the manipulation of MT patterns and other active matter systems.
Soft Condensed Matter (cond-mat.soft), Biomolecules (q-bio.BM), Subcellular Processes (q-bio.SC)
6 pages, 4 figures
Extreme value statistics in a continuous time branching process: a pedagogical primer
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
Satya N. Majumdar, Alberto Rosso
We study a continuous time branching process where an individual splits into two daughters with rate b and dies with rate a, starting from a single individual at t=0. We show that the model can be mapped exactly to a random walk problem where the population size N(t) performs a random walk on a positive semi-infinite lattice. The hopping rate of this random walker out of a site labelled n is proportional to n, i.e., the walker gets more and more agitated' as it moves further and further away from the origin--we call this an agitated random walk’ (ARW). We demonstrate that this random walk problem is particularly suitable to obtain exact explicit results on the extreme value statistics, namely, on the distribution of the maximal population size M(t)= \max_{0\tau\le t}[N(\tau)] up to time t. This extreme value distribution displays markedly different behaviors in the three phases: (i) subcritical (b<a) (ii) critical (b=a) and (iii) supercritical (b>a). In the subcritical and critical phases , Q(L,t) becomes independent of time t for large t and the stationary distribution Q(L, \infty) decays to zero with increasing L, respectively exponentially (subcritical) and algebraically (critical). For finite but large t, the distribution at the critical point exhibits a scaling form Q(L,t)\sim f_c(L/{at})/L^2 where the scaling function f_c(z) has a nontrivial shape that we compute analytically. In the supercritical phase, the distribution Q(L,t) has a fluid' part that becomes independent of t for large t and a condensate’ part (a delta peak centered at e^{(b-a)t}) which gets disconnected from the `fluid’ part and moves rapidly to \infty as time increases. We also verify our analytical predictions via numerical simulations finding excellent agreement.
Statistical Mechanics (cond-mat.stat-mech)
teMatDb: A High-Quality Thermoelectric Material Database with Self-Consistent ZT Filtering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Byungki Ryu, Ji Hui Son, Sungjin Park, Jaywan Chung, Hye-Jin Lim, SuJi Park, Yujeong Do, SuDong Park
This study presents a curated thermoelectric material database, teMatDb, constructed by digitizing literature-reported data. It includes temperature-dependent thermoelectric properties (TEPs), Seebeck coefficient, electrical resistivity, thermal conductivity, and figure of merit (ZT), along with metadata on materials and their corresponding publications. A self-consistent ZT (Sc-ZT) filter set was developed to measure ZT errors by comparing reported ZT’s from figures with ZT’s recalculated from digitized TEPs. Using this Sc-ZT protocol, we generated tMatDb272, comprising 14,717 temperature-property pairs from 272 high-quality TEP sets across 262 publications. The method identifies various types of ZT errors, such as resolution error, publication bias, ZT overestimation, interpolation and extrapolation error, and digitization noise, and excludes inconsistent samples from the dataset. teMatDb272 and the Sc-ZT filtering framework offer a robust dataset for data-driven and machine-learning-based materials design, device modeling, and future thermoelectric research.
Materials Science (cond-mat.mtrl-sci)
43 pages, 4 tables, 5 figures, 3 supporting tables, 10 supporting figures
Revealing molecule-internal mechanisms that control phonon heat transport through single-molecule junctions by a genetic algorithm
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Matthias Blaschke, Fabian Pauly
Measurements of the thermal conductance of single-molecule junctions have recently been reported for the first time. It is presently unclear, how much the heat transport can be controlled through molecule-internal effects. The search for molecules with lowest and highest thermal conductance is complicated by the gigantic chemical space. Here we describe a systematic search for molecules with a low or a high phononic thermal conductance using a genetic algorithm. Beyond individual structures of well performing molecules, delivered by the genetic algorithm, we analyze patterns and identify the different physical and chemical mechanisms to suppress or enhance phonon heat flow. In detail, mechanisms revealed to reduce phonon transport are related to the choice of terminal linker blocks, substituents and corresponding mass disorder or destructive interference, meta couplings and molecule-internal twist. For a high thermal conductance, the molecules should instead be rather uniform and chain-like. The identified mechanisms are systematically analyzed at different levels of theory, and their significance is classified. Our findings are expected to be important for the emerging field of molecular phononics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
main text (16 pages, 9 figures) and supporting information (12 pages, 9 figures)
A many-body marker for three-dimensional topological insulators with inversion symmetry
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Federico Becca, Alberto Parola
We introduce a generalization of the previously defined many-body marker for two-dimensional $ \mathbb{Z}_2$ topological insulators [I. Gilardoni {\it et al.}, Phys. Rev. B {\bf 106}, L161106 (2022)] to distinguish trivial, weak-, and strong-topological insulators in three dimensions, in presence of the inversion symmetry. The marker is written in term of ground-state expectation values of position operators and can be employed to detect topological phases of interacting systems beyond mean-field approximations, e.g., within quantum Monte Carlo techniques. Here, we show that the correct results of the non-interacting limit is reproduced by the many-body marker.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages and 1 figure
Agentic Information Theory: Ergodicity and Intrinsic Semantics of Information Processes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
James P. Crutchfield, Alexandra Jurgens
We develop information theory for the temporal behavior of memoryful agents moving through complex – structured, stochastic – environments. We introduce information processes – stochastic processes produced by cognitive agents in real-time as they interact with and interpret incoming stimuli. We provide basic results on the ergodicity and semantics of the resulting time series of Shannon information measures that monitor an agent’s adapting view of uncertainty and structural correlation in its environment.
Statistical Mechanics (cond-mat.stat-mech), Information Theory (cs.IT), Multiagent Systems (cs.MA), Adaptation and Self-Organizing Systems (nlin.AO)
24 pages, 10 figures, 1 appendix; this http URL
C-BerryANC: A first-principle C++ code to calculate Berry Curvature dependent anomalous Nernst conductivity in any material
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Vivek Pandey, Sudhir K. Pandey
The anomalous Nernst conductivity (ANC) is a key transport property in magnetic and topological materials, arising from the Berry curvature ($ \boldsymbol\Omega$ ) of electronic bands. It offers deep insight into the underlying topology and thermoelectric behavior. While Wannier interpolation have become popular for calculating ANC due to their computational efficiency, their accuracy critically depends on the quality of the Wannierization, which can be challenging for entangled bands or materials with complex band crossings. These limitations highlight the need for a direct first-principles approach to reliably compute ANC from ab-initio electronic structures. Here, we present a C++ based code named C-BerryANC that calculates $ \boldsymbol\Omega$ -dependent ANC by directly using the eigenvalues and momentum-matrices obtained from DFT calculations. Presently, the code is interfaced with WIEN2k package which uses all-electron approach and full-potential linearized augmented plane wave (FP-LAPW) based method. For efficiently handling dense k-mesh, calculation of $ \boldsymbol\Omega$ is made parallel over k-points using the OpenMP method. Additionally, the code stores band-resolved components of $ \boldsymbol\Omega$ in binary files thereby reducing the memory occupancy and providing fast post-process option to compute ANC for any range of chemical potential and temperature values. Also, as compilation of C++ modules produce executable files which are in machine level language, computational speed of C-BerryANC is very fast. The code is benchmarked over some well-known materials exhibiting ANC. These includes- Pd, Fe$ _3$ Al & Co$ _2$ FeAl. The obtained values of ANC is found to in good agreement with the previously reported data. This highlights the accuracy, efficieny and reliability of the C-BerryANC code.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Exploring Self-Organized Criticality through Memory-Driven Random Walks on Complex Networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
We present a stochastic model of memory-driven random walks on complex networks, where a single walker explores the network through a combination of local random walks and memory-based resetting. The walker either moves to a neighboring node or resets to a previously visited node with a probability proportional to the visitation this http URL node in the network accumulates stress with every visit, and once the accumulated stress exceeds a threshold, the node topples, redistributing the stress to its neighbors. This redistribution can trigger cascading avalanches across the network. We demonstrate that this simple memory-driven mechanism, combined with local stress dynamics, leads to the emergence of self-organized criticality (SOC) across various network topologies, including Small-World and BA this http URL resulting avalanche size distributions follow power-law statistics, with exponents that are consistent with those found in classical SOC systems. Our model requires no fine-tuning of parameters to achieve criticality and offers a novel insight into how memory, network structure, and local stress interactions can give rise to emergent critical phenomena. These findings have implications for understanding cascading failures in infrastructure, neural avalanches in brain dynamics, and information spread in complex networks.
Statistical Mechanics (cond-mat.stat-mech)
Review of point defect structures in hexagonal close packed metals and across the Periodic Table
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Andrew Ralph Warwick, Pui-Wai Ma, Sergei Lvovich Dudarev
We present a comprehensive ab initio dataset of formation energies and elastic properties of intrinsic point defects across all the transition and rare earth hexagonal close packed (hcp) metals, as well as metalloid elements with hcp crystal structure. Point defect properties appear weakly correlated with the c/a ratio of the hcp lattice. Instead, it is the position of an element in the Periodic Table that primarily defines the relaxation volume tensor, elastic dipole tensor and formation energy of a point defect. This suggests that the local variations in the electronic structure and interatomic bonding at the core of a defect dominate its properties, as opposed to long-range elastic deformations. Across all the metals, we find that the relaxation volumes of vacancies and self-interstitial defects are correlated with atomic volumes, with values of -0.35 and 1.46 atomic volumes for a vacancy and a self-interstitial defect, respectively, providing a universally good approximation independent of the crystal structure. This study complements and completes the existing point defect databases spanning body-centred cubic and face-centred cubic metals.
Materials Science (cond-mat.mtrl-sci)
Structural, magnetic, and nanoacoustic characterization of Co/Pt superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
E. R. Cardozo de Oliveira, C. Xiang, C. Borrazás, S. Sandeep, J. E. Gómez, M. Vásquez Mansilla, N. Findling, L. Largeau, N. D. Lanzillotti-Kimura, M. Granada
Superlattices presenting a spatial modulation of the elastic properties appear as a main tool to reach the THz regime in nanoacoustic devices. The exploration of alternative materials with multifunctional properties remains a fertile domain of research. In this work, we study the structural, magnetic, and acoustic characteristics of nanometric superlattices made of Pt/Co.
The samples present a well defined periodicity, as determined by X-ray reflectometry, whereas scanning transmission electron microscopy with local compositional analysis reveals that the superlattices present a modulation in composition instead of sharp interfaces. The policrystalline nature of the superlattices is evidenced both by X ray diffraction and transmission electron microscopy. Magnetization measurements show a perpendicular magnetic anisotropy for the higher Co concentrations. Picosecond acoustic experiments evidence that the studied samples support short-lived acoustic modes up to 900 GHz, and up to 7 acoustic echoes at lower this http URL are promising results for the development of magnetoacoustic devices working at ultrahigh frequencies.
Materials Science (cond-mat.mtrl-sci)
21 pages, 8 figures, 1 table
Disorder-Induced Suppression of Antiferromagnetic Magnon Transport in Cr2O3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Josiah Keagy, Haoyu Liu, Junyu Tang, Weilun Tan, Wei Yuan, Sumukh Mahesh, Ran Cheng, Jing Shi
We explore the impact of spin disorder associated with structural defects on antiferromagnetic magnon transport by probing the spin-flop transition of Cr2O3 using spin Seebeck effect measurements. By fabricating homoepitaxial Cr2O3 films grown on smooth Cr2O3 crystals, we systematically vary the thickness of the films in which the presence of point defects modulates the spin-flop transition field. We find that magnon propagation through the film is entirely suppressed for film thickness greater than 3 nm, revealing the pivotal role of disorder in governing antiferromagnetic magnon transport.
Materials Science (cond-mat.mtrl-sci)
Driven Probe Particle Dynamics in a Bubble Forming System
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
C. Reichhardt, C.J.O. Reichhardt
We numerically examine the dynamics of a probe particle driven at a constant force through an assembly of particles with competing long-range repulsion and short-range attraction that forms a bubble or stripe state. In the bubble regime, we identify several distinct types of motion, including an elastic or pinned regime where the probe particle remains inside a bubble and drags all other bubbles with it. There is also a plastic bubble phase where the bubble in which the probe particle is trapped is able to move past the adjacent bubbles. At larger drives, there is a breakthrough regime where the probe particle jumps from bubble to bubble, and in some cases, can induce correlated rotations or plastic rearrangements of the particles within the bubbles. At the highest drives, the probe particle moves sufficiently rapidly that the background particles undergo only small distortions. The distinctive dynamic flow states and the transitions between them are accompanied by signatures in the effective drag on the driven particle, jumps in the velocity-force curves, and changes in the time-dependent velocity fluctuations. We map the dynamic phase diagram for this system for varied interaction lengths, bubble sizes, and densities.
Soft Condensed Matter (cond-mat.soft)
10 pages, 15 figures
Fluctuations in DNA Packing Density Drive the Spatial Segregation between Euchromatin and Heterochromatin
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Luming Meng, Boping Liu, Qiong Luo
In the crowded eukaryotic nucleus, euchromatin and heterochromatin segregate into distinct compartments, a phenomenon often attributed to homotypic interactions mediated by liquid liquid phase separation of chromatin associated proteins. Here, we revisit genome compartmentalization by examining the role of in vivo DNA packing density fluctuations driven by ATP dependent chromatin remodelers. Leveraging DNA accessibility data, we develop a polymer based model that captures these fluctuations and successfully reproduces genome wide compartment patterns observed in HiC data, without invoking homotypic interactions. Further analysis reveals that density fluctuations in a crowded nuclear environment elevate the system energy, while euchromatin heterochromatin segregation facilitates energy dissipation, offering a thermodynamic advantage for spontaneous compartment formation. These findings suggest that euchromatin heterochromatin segregation may arise through a non equilibrium, self organizing process, providing new insights into genome organization.
Soft Condensed Matter (cond-mat.soft), Genomics (q-bio.GN)
Universal Symmetries in Twisted Moiré Materials
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Mohammed M. Al Ezzi, Albert Zhu, Daniel Bennett, Daniel T. Larson, Efthimios Kaxiras
Two-dimensional multi-layer materials with an induced moiré pattern, either due to strain or relative twist between layers, provide a versatile platform for exploring strongly correlated and topological electronic phenomena. While these systems offer unprecedented tunability, their theoretical description remains challenging due to their complex atomic structures and large unit cells. A notable example is twisted bilayer graphene, where even the relevant symmetry group remains unsettled despite its critical role in constructing effective theories. Here, we focus on twisted bilayer graphene and use a combination of analytical methods, molecular dynamics simulations, and first-principles calculations to show that twisted atomic configurations with distinct microscopic symmetries converge to a universal interlayer structure that governs the low-energy physics. This emergent universality provides a robust foundation for symmetry-respecting models and offers insight into the role of commensurability in real twisted moiré systems.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures
Improvement of the simplification method for the local two-particle full-vertex towards precise frequency behavior
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Ryota Mizuno, Kazuhiko Kuroki, Masayuki Ochi
Estimating the local two-particle vertex functions, which are crucial for capturing the spatial fluctuation of the effective field beyond the single-site DMFT, is still challenging. In our previous work, we developed a computationally efficient method for estimating the local full-vertex in DMFT, where we can obtain the local two-particle full-vertex from the one-particle self-energy. In this study, we further enhance our method by refining its formulation to be more faithful to the diagrammatic structure of the full-vertex. With this improvement, we can qualitatively reproduce the characteristic frequency structures of the full-vertex obtained by the numerically exact methods. In particular, the improved version of the simplified full-vertex captures a sharp value change in the cross structure.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 10 figures, 1 table
Phys. Rev. B 111, 205136 (2025)
$b$-axis and $c$-axis Knight shift measurements in the superconducting state on ultraclean UTe$_2$ with $T_c$ = 2.1 K
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-27 20:00 EDT
Hiroki Matsumura, Yuki Takahashi, Katsuki Kinjo, Shunsaku Kitagawa, Kenji Ishida, Yo Tokunaga, Hironori Sakai, Shinsaku Kambe, Ai Nakamura, Yusei Shimizu, Yoshiya Homma, Dexin Li, Fuminori Honda, Atsushi Miyake, Dai Aoki
Knight shifts along the $ b$ and $ c$ axes ($ K_b$ and $ K_c$ ) at two crystallographically distinct Te sites were measured down to 70 mK using $ ^{125}$ Te nuclear magnetic resonance (NMR) on an ultraclean UTe$ 2$ single crystal with a superconducting (SC) transition temperature $ T{\mathrm{c}}$ = 2.1 K. This was carried out to determine the $ \boldsymbol{d}$ -vector components, which are the order parameter in the spin-triplet pairing. Although the decrease in $ K_b$ and $ K_c$ is comparable to the theoretical estimation of the SC diamagnetic shielding effect, it is confirmed, by taking the difference between two Knight shifts at the distinct Te sites, that the spin susceptibility along the $ b$ and $ c$ axes decreases in the SC state. Taking into account the large decrease in $ K_a$ in the SC state, we conclude that the $ \boldsymbol{d}$ vector has components along all three crystal axes.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 7 figures
Phys. Rev. B 111, 174526 (2025)
In-depth Investigation of Conduction Mechanism on Defect-induced Proton-conducting Electrolytes BaHfO$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Peng Feng, Hang Ma, Kuan Yang, Yingjie Lv, Ying Liang, Tianxing Ma, Jiajun Linghu, Zhi-Peng Li
This study utilizes first-principles computational methods to comprehensively analyze the impact of A-site doping on the proton conduction properties of BaHfO$ _3$ . The goal is to offer theoretical support for the advancement of electrolyte materials for solid oxide fuel cells. Our research has uncovered that BaHfO$ _3$ demonstrates promising potential for proton conduction, with a low proton migration barrier of 0.28 eV, suggesting efficient proton conduction can be achieved at lower temperatures. Through A-site doping, particularly with low-valence state ions and the introduction of Ba vacancies, we can effectively decrease the formation energy of oxygen vacancies (Evac), leading to an increase in proton concentration. Additionally, our study reveals that the primary mechanism for proton migration in BaHfO$ _3$ is the Grotthuss mechanism rather than the Vehicle mechanism. Examination of the changes in lattice parameters during proton migration indicates that while doping or vacancy control strategies do not alter the mode of H+ migration, they do influence the migration pathway and barrier. These findings provide valuable insights into optimizing the proton conduction properties of BaHfO$ _3$ through A-site doping and lay a solid theoretical foundation for the development of novel, highly efficient Solid oxide fuel cell electrolyte materials.
Materials Science (cond-mat.mtrl-sci)
Longitudinal magnetoconductivity in chiral multifold semimetals exemplified by pseudospin-1 nodal points
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
We embark on computing the longitudinal magnetoconductivity within the semiclassical Boltzmann formalism, where an isotropic triple-point semimetal (TSM) is subjected to collinear electric ($ \boldsymbol E $ ) and magnetic ($ \boldsymbol B$ ) fields. Except for the Drude part, the $ B$ -dependence arises exclusively from topological properties like the Berry curvature and the orbital magnetic moment. We solve the Boltzmann equations exactly in the linear-response regime, applicable in the limit of weak/nonquantising magnetic fields. The novelty of our investigation lies in the consideration of the truly multifold character of the TSMs, where the so-called flat-band (flatness being merely an artifact of linear-order approximations) is made dispersive by incorporating the appropriate quadratic-in-momentum correction in the effective Hamiltonian. It necessitates the consideration of interband scatterings within the same node as well, providing a complex interplay of intraband, interband, intranode, and internode processes. The exact results are compared with those obtained from a naive relaxation-time approximation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
13 pages, 4 figures
Spin-Waves without Spin-Waves: A Case for Soliton Propagation in Starling Flocks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
Andrea Cavagna, Guido Cimino, Javier Cristín, Matteo Fiorini, Irene Giardina, Angelo Giustiniani, Tomás S. Grigera, Stefania Melillo, Roberto A. Palombella, Leonardo Parisi, Antonio Ponno, Mattia Scandolo, Zachary S. Stamler
Collective turns in starling flocks propagate linearly with negligible attenuation, indicating the existence of an underdamped sector in the dispersion relation. Beside granting linear propagation of the phase perturbations, the real part of the frequency should also yield a spin-wave form of the unperturbed correlation function. However, new high-resolution experiments on real flocks show that underdamped traveling waves coexist with an overdamped Lorentzian correlation. Theory and experiments are reconciled once we add to the dynamics a Fermi-Pasta-Ulam-Tsingou term.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Magnon-Driven Phononic Frequency Comb in Linear Elastic Media
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Ziyang Yu, Zhejunyu Jin, Qianjun Zheng, Peng Yan
Phononic frequency combs (PFCs) typically require nonlinear elastic media, limiting their frequency range and stability. Here, we propose a transformative approach to generate PFCs in purely linear elastic media by harnessing the magnon nonlinearities, offering a new paradigm for frequency comb physics. By tuning the magnon-phonon coupling confined in a magnetic disk of a vortex state into the strong coupling regime, we demonstrate an efficient nonlinearity transfer from magnons to phonons. This mechanism is able to produce GHz-range PFCs with comb spacing set by the vortex core’s gyration frequency. Full micromagnetic simulations verify our theoretical predictions, confirming robust comb formation at 3.5 GHz with 0.4 GHz spacing. This approach overcomes the sub-MHz constraints of conventional PFCs, enabling applications in high-precision metrology, nanoscale sensing, and quantum technologies. Our findings also deepen the understanding of the nonlinear dynamics in hybrid magnon-phonon systems and provide a versatile platform for exploring frequency combs in diverse physical systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Symmetry-broken charge-ordered ground state in CsV$_3$Sb$_5$ Kagome metal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Manex Alkorta, Martin Gutierrez-Amigo, Chunyu Guo, Philip J. W. Moll, Maia G. Vergniory, Ion Errea
The newly discovered family of non-magnetic Kagome metals AV$ _3$ Sb$ _5$ (A=K,Rb,Cs) offers a unique platform for studying the interplay between a charge density wave transition with superconductivity, non-trivial topology, and spontaneous time-reversal this http URL characterizing the charge density wave phase is crucial to understand and model all these exotic properties, it remains unresolved. In this work, we use first-principles calculations of the free-energy, incorporating both ionic kinetic energy and anharmonic effects, to resolve the atomistic phase diagram of CsV$ _3$ Sb$ _5$ and its charge ordering structure. Our results reveal a competition between metastable stacking orders of the reconstructed vanadium Kagome layers, which are energetically favored to form exclusively a triangular-hexagonal arrangement, allowing the possibility of competitive different domains and chiral order. Consistent with experimental observations, we find that the $ 2\times2\times2$ and $ 2\times2\times4$ modulations are nearly degenerate in free energy, and are abruptly melted into the high-symmetry hexagonal phase around 90 K. The transition is first-order but compatible with a measurable phonon-softening. Remarkably, even if the six-fold and inversion symmetry are intrinsically broken by the out-of-plane stacking, this does not lead to measurable anisotropy in the in-plane conductivity as suggested by measurements.
Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Composition dependent $\mathbf{k}\cdot\mathbf{p}$ band parameters for wurtzite (Al,Ga)N alloys from density functional theory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Amit Kumar Singh, Alvaro Gomez-Iglesias, Stefan Schulz
UV emitters based on the semiconductor alloy aluminium gallium nitride, (Al,Ga)N, have attracted significant interest in recent years due to their potential for optoelectronic devices. To guide the design of such devices with improved efficiencies, theoretical frameworks based on so-called k.p methods have found widespread application in the literature. Given that k.p models are empirical in nature, parameters such as effective masses or crystal field splitting energies of (Al,Ga)N alloys have to be provided as input from first-principles calculations or experiment. Although these parameters are available for GaN and AlN, detailed information on their composition dependence is sparse. Here, we address this question and provide (Al,Ga)N band parameters for widely used k.p Hamiltonians. We start from density functional theory (DFT) to sample the electronic structure of (Al,Ga)N alloys over the full composition range. The k.p parameters are treated as free parameters to reproduce the DFT data. For GaN and AlN the parameters extracted here agree well with literature values. When turning to the composition dependence of the k.p parameters, our calculations show that most parameters deviate significantly from a linear interpolation of the GaN and AlN values, an approximation widely made in the literature. Moreover, to describe changes in the band parameters with Al content, composition dependent bowing parameters have to be considered for an accurate description of the DFT data. Finally, our analysis also provides initial insight into consequences of the nonlinear composition dependence of the k.p parameters for the electronic structure of (Al,Ga)N alloys. We find that in particular the band ordering is affected by the nonlinear evolution of the crystal field splitting energy with composition, an important aspect for the light polarization characteristics of high Al content (Al,Ga)N alloys.
Materials Science (cond-mat.mtrl-sci)
17 pages, 8 figures
Machine Learning the Energetics of Electrified Solid/Liquid Interfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Nicolas Bergmann, Nicéphore Bonnet, Nicola Marzari, Karsten Reuter, Nicolas G. Hörmann
We present a response-augmented machine learning (ML) approach to the energetics of electrified metal surfaces. We leverage local descriptors to learn the work function as the first-order energy change to introduced bias charges and stabilize this learning through Born effective charges. This permits the efficient extension of ML interatomic potential architectures to include finite bias effects up to second-order. Application to OH at Cu(100) rationalizes the experimentally observed pH-dependence of the preferred adsorption site in terms of a non-Nernstian charge-induced site switching.
Materials Science (cond-mat.mtrl-sci)
Boundary local time on wedges and prefractal curves
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
We investigate the boundary local time on polygonal boundaries such as finite generations of the Koch snowflake. To reveal the role of angles, we first focus on wedges and obtain the mean boundary local time, its variance, and the asymptotic behavior of its distribution. Moreover, we establish the coupled partial differential equations for higher-order moments. Next, we propose an efficient multi-scale Monte Carlo approach to simulate the boundary local time, as well as the escape duration and position of the associated reaction event on a polygonal boundary. This numerical approach combines the walk-on-spheres algorithm in the bulk with an approximate solution of the escape problem from a sector. We apply it to investigate how the statistics of the boundary local time depends on the geometric complexity of the Koch snowflake. Eventual applications to diffusion-controlled reactions on partially reactive boundaries, including the asymptotic behavior of the survival probability, are discussed.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
37 pages, 12 figures
Giant spontaneous polarization in zincblende III-V semiconductors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Jesus Cañas, Mohamed Yassine, Oliver Ambacher
The discovery of ferroelectricity in wurtzite nitrides has paved the way for measuring and understanding spontaneous polarization in III-V semiconductors. However, the calculation of polarization effects at heterointerfaces - crucial for numerous electronic and photonic applications - remains a topic of debate. The need for a reference structure to calculate spontaneous polarization has led to discussions over whether to use the zincblende or layered hexagonal structures as the reference for wurtzite crystals. In this work, we argue that the layered hexagonal structure is not only a better reference due to its vanishing formal polarization but also the only physically correct choice for the wurtzite system. This follows from the fact that spontaneous polarization is rigorously defined through the ferroelectric switching. Applying this definition, we extend our analysis to III-V zincblende semiconductors and reveal that their spontaneous polarization is approximately three times larger than that of wurtzite, thereby refuting the longstanding assumption that it is zero. Through this example, we illustrate that spontaneous polarization is not inherently linked to charge density at interfaces.
Materials Science (cond-mat.mtrl-sci)
Statistical physics of active matter, cell division and cell aggregation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Jean-François Joanny, Joseph O. Indekeu
In these Lecture Notes we aim at clarifying how soft matter physics, and herein notably statistical mechanics and fluid mechanics, can be engaged to understand and manipulate non-equilibrium systems consisting of numerous (microscopic) constituents that convert (chemical) energy to mechanical energy, or vice versa, and that are known as active matter. Hydrodynamic theory, vitally extended to include (anisotropic) active stress, provides an astonishingly successful scaffold for tackling the problem of spontaneous flow in active nematics, all the way to active turbulence. The laws of physics, nonchalantly tresspassing the border crossing between inanimate particle and living cell, are seen to perform cum laude in describing the bi-directional coupling between division and apoptosis on the one hand and mechanical stress on the other. Fluidization of cellular tissue by cell division is a conceptual leap in this arena. The active behavior of nematic tissues (cell extrusion, multilayer formation, …) turns out to be controlled by topological defects in the orientational order. Playgrounds by excellence for exhibiting stress-growth coupling are multicellular spheroids serving as model tumors, and cysts used as stem cell factories for cell therapy. Finally, our study of villi and crypts in the intestine furnishes a synthesis of various concepts explored. Cell mechanical pressure and cell layer geometrical curvature turn out to provide the dynamical ingredients which, when coupled to the cell division rate, allow one to develop a physical theory of tissue morphology which hopefully will have practical impact on cancer research.
Soft Condensed Matter (cond-mat.soft)
Lecture Notes of the International Summer School “Fundamental Problems in Statistical Physics XV”
Physica A 631, 129314 (2023)
Density-Functional Green Function Theory: Dynamical exchange-correlation field in lieu of self-energy
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
The one-particle Green function of a many-electron system is traditionally formulated within the self-energy picture. A different formalism was recently proposed, in which the self-energy is replaced by a dynamical exchange-correlation field, which acts on the Green function locally in both space and time. It was found that there exists a fundamental quantity, referred to as the dynamical exchange-correlation hole, which can be interpreted as effective density fluctuations induced in a many-electron system when a hole or an electron is introduced into the system, as in photoemission and inverse photoemission experiments. The dynamical exchange-correlation potential is simply the Coulomb potential of this exchange-correlation hole, which fulfils a sum rule and an exact constraint, identical to those satisfied by the static exchange-correlation hole in density-functional theory. The proposed formalism has been applied to a number of model systems such as the half-filled one-dimensional Hubbard model, the one-dimensional antiferromagnetic Heisenberg model, and the single-impurity Anderson model. The dynamical exchange-correlation hole and field of the homogeneous electron gas have also been studied with the view of constructing a density-functional approximation such as the local-density approximation. The availability of simple but accurate approximations for the exchange-correlation potential would circumvent costly computations of the traditional self-energy. The formalism may also provide new perspectives and insights into the many-body problem.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
46 pages, 31 figures
Beyond the Electric Dipole Approximation: Electric and Magnetic Multipole Contributions Reveal Biaxial Water Structure from SFG Spectra at the Air-Water Interface
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
Louis Lehmann, Maximilian R. Becker, Lucas Tepper, Alexander P. Fellows, Álvaro Díaz Duque, Martin Thämer, Roland R. Netz
The interpretation of sum-frequency generation (SFG) spectra has been severely limited by the absence of quantitative theoretical predictions for multipole contributions. The previously unknown magnetic dipole and electric quadrupole contributions are determined by the bulk media but appear in all experimental SFG spectra, obscuring the connection between measured spectra and interfacial structure. We present the simulation-based framework that predicts the full set of multipole contributions to the SFG spectrum. This framework also yields depth-resolved spectra, enabling the precise localization of spectroscopic features. Applied to the air-water interface, our approach achieves quantitative agreement with experimental spectra for different polarization combinations in both the bending and stretching regions. Multipole contributions are crucial for correctly interpreting SFG spectra: in the bending band, the electric dipole contribution is of an intensity similar to the magnetic dipole contribution, and both are dominated by the electric quadrupole contribution. In the OH-stretch region, the electric quadrupole contribution is found to be responsible for the mysterious shoulder at 3600 cm$ ^{-1}$ . Crucially, subtracting the multipole contributions isolates the second-order electric dipole susceptibility, which is a quantitative probe for interfacial orientational anisotropy. This electric-dipole susceptibility reveals a pronounced biaxial ordering of water at the air-water interface. By resolving a fundamental limitation of the interpretation of SFG spectroscopy, our framework allows for the detailed extraction of interfacial water ordering from SFG spectra.
Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Design Rules for Optimizing Quaternary Mixed-Metal Chalcohalides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Pascal Henkel, Jingrui Li, Patrick Rinke
Quaternary mixed-metal M(II)2M(III)Ch2X3 chalcohalides are an emerging material class for photovoltaic absorbers that combines the beneficial optoelectronic properties of lead-based halide perovskites with the stability of metal chalcogenides. Inspired by the recent discovery of lead-free mixed-metal chalcohalides materials, we utilized a combination of density functional theory and machine learning to determine compositional trends and chemical design rules in the lead-free and lead-based materials spaces. We explored a total of 54 M(II)2M(III)Ch2X3 materials with M(II) = Sn, Pb, M(III) = In, Sb, Bi, Ch = S, Se, Te, and X = Cl, Br, I per phase (Cmcm, Cmc21 , and P21/c). The P21/c phase is the equilibrium phase at low temperatures, followed by Cmc21 and Cmcm. The fundamental band gaps in Cmcm and Cmc21 are smaller than those in P21/c, but direct band gaps are more common in Cmcm and Cmc21. The effective electron masses in P21/c are significantly larger compared to Cmcm and Cmc21, while the effective hole masses are nearly the same across all three phases. Using random forest regression, we found that the two electron acceptor sites (Ch and X) are crucial in shaping the properties of mixed-metal chalcohalide compounds. Furthermore, the electron donor sites (M(II) and M(III)) can be used to finetune the material properties to desired applications. These design rules enable precise tailoring of mixed-metal chalcohalide compounds for a variety of applications.
Materials Science (cond-mat.mtrl-sci)
Laser-dressed partial density of states
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Tatiana Bezriadina, Daria Popova-Gorelova
The manipulation of material properties by laser light holds great promise for the development of future technologies. However, the full picture of the electronic response to laser driving remains to be uncovered. We present a novel approach to reveal details of the electron dynamics of laser-dressed materials, which consists of calculating and analysing the time-dependent partial density of states (PDOS) of materials during their interaction with a driving electromagnetic field. We show that the laser-dressed PDOS provides information about the structure of the bonds that form the laser-dressed electron density, analogous to the information that a PDOS can provide about the electron structure in a field-free case. We illustrate how our method can provide insights into the electron dynamics of materials in a site- and orbital-selective manner with calculations for a laser-dressed wurtzite ZnO crystal. Our work provides an analytical tool for the interpretation of subcycle-resolved experiments on laser-dressed materials and for the development of strategies for optical manipulation of material properties.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Yielding and memory in a driven mean-field model of glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-27 20:00 EDT
Makoto Suda, Edan Lerner, Eran Bouchbinder
Glassy systems reveal a wide variety of generic behaviors inherited from their intrinsically-disordered, non-equilibrium nature. These include universal non-phononic vibrational spectra, and driven phenomena such as thermal and mechanical annealing, yielding transitions and memory formation, all linked to the underlying complex energy landscape of glasses. Yet, a unified theory of such diverse glassy phenomena is currently lacking. Here, we study a recently introduced mean-field model of glasses, shown to reproduce the universal non-phononic vibrational spectra of glasses, under oscillatory driving forces. We show that the driven mean-field model, admitting a Hamiltonian formulation in terms of a collection of random-stiffness anharmonic oscillators with disordered interactions, naturally predicts the salient dynamical phenomena in cyclically deformed glasses. Specifically, it features a yielding transition as a function of the amplitude of the oscillatory driving force, characterized by an absorbing-to-diffusive transition in the system’s microscopic trajectories and large-scale hysteresis. The model also reveals dynamic slowing-down from both sides of the transition, as well as mechanical and thermal annealing effects that mirror their glass counterparts. We demonstrate a non-equilibrium ensemble equivalence between the driven post-yielding dynamics at fixed quenched disorder and quenched disorder averages of the non-driven system. Finally, mechanical memory formation is demonstrated, in which memories can be stored in the model and subsequently extracted. Overall, the mean-field model offers a theoretical framework that unifies a broad range of glassy behaviors.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Diffusion with stochastic resetting on a lattice
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
Alexander K. Hartmann, Satya N. Majumdar
We provide an exact formula for the mean first-passage time (MFPT) to a target at the origin for a single particle diffusing on a $ d$ -dimensional hypercubic {\em lattice} starting from a fixed initial position $ \vec R_0$ and resetting to $ \vec R_0$ with a rate $ r$ . Previously known results in the continuous space are recovered in the scaling limit $ r\to 0$ , $ R_0=|\vec R_0|\to \infty$ with the product $ \sqrt{r}, R_0$ fixed. However, our formula is valid for any $ r$ and any $ \vec R_0$ that enables us to explore a much wider region of the parameter space that are inaccessible in the continuum limit. For example, we have shown that the MFPT, as a function of $ r$ for fixed $ \vec R_0$ , diverges in the two opposite limits $ r\to 0$ and $ r\to \infty$ with a unique minimum in between, provided the starting point is not a nearest neighbour of the target. In this case, the MFPT diverges as a power law $ \sim r^{\phi}$ as $ r\to \infty$ , but very interestingly with an exponent $ \phi= (|m_1|+|m_2|+\ldots +|m_d|)-1$ that depends on the starting point $ \vec R_0= a, (m_1,m_2,\ldots, m_d)$ where $ a$ is the lattice spacing and $ m_i$ ‘s are integers. If, on the other hand, the starting point happens to be a nearest neighbour of the target, then the MFPT decreases monotonically with increasing $ r$ , approaching a universal limiting value $ 1$ as $ r\to \infty$ , indicating that the optimal resetting rate in this case is infinity. We provide a simple physical reason and a simple Markov-chain explanation behind this somewhat unexpected universal result. Our analytical predictions are verified in numerical simulations on lattices up to $ 50$ dimensions. Finally, in the absence of a target, we also compute exactly the position distribution of the walker in the nonequlibrium stationary state that also displays interesting lattice effects not captured by the continuum theory.
Statistical Mechanics (cond-mat.stat-mech), Data Analysis, Statistics and Probability (physics.data-an)
17 pages, 7 figures, data gnuplot files for plots available at this https URL
Disentangling hierarchical relaxations in glass formers via dynamic eigenmodes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Wensi Sun, Yanshuang Chen, Wencheng Ji, Yi Zhou, Hua Tong, Ke Chen, Xiaosong Chen, Hajime Tanaka, Peng Tan
Hierarchical dynamics in glass-forming systems span multiple timescales, from fast vibrations to slow structural rearrangements, appearing in both supercooled fluids and glassy states. Understanding how these diverse processes interact across timescales remains a central challenge. Here, by combining direct particle-level observations with a dynamic eigenmode approach that decomposes intermediate-timescale responses into distinct modes, we reveal the microscopic organisation of relaxation dynamics in two-dimensional colloidal systems. We identify five classes of modes characterizing hierarchical dynamics: (i) quasi-elastic modes, (ii) slow-reversible string modes contributing to dynamic heterogeneity, (iii) slow-irreversible string modes leading to flow, (iv) fast-$ \beta$ modes with fast-reversible strings, and (v) random noise modes. The emergence of quasi-elastic modes marks the onset of glassy dynamics, while reversible string modes dominate dynamic heterogeneity throughout both supercooled and glassy regimes. Our findings offer a unified microscopic framework for understanding how distinct relaxation processes interconnect across timescales, illuminating the mechanisms driving glass formation.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn)
37 pages, 3 figures, 8 extended data figures
Nonlinear Transport in Carbon Quantum Dot Electronic Devices: Experiment and Theory
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-27 20:00 EDT
Scott Copeland, Sungguen Ryu, Kazunari Imai, Nicholas Krasco, Zhixiang Lu, David Sanchez, Paul Czubarow
Carbon quantum dots (CQDs) are a promising material for electronic applications due to their easy fabrication and interesting semiconductor properties. Further, CQDs exhibit quantum confinement and charging effects, which may lead not only to improved performances but also to devices with novel functionalities. Here, we investigate the electronic transport of CQDs embedded on epoxy polymer. Our samples are coupled to interdigitated electrodes with individually addressable microelectrodes. Remarkably, the current-voltage characteristics show strongly nonlinear regimes at room temperature, ranging from Schottky diode to Coulomb blockade and even negative differential conductance behavior. We propose a master equation theoretical framework which allows us to compute current curves that agree well with the observations. This model emphasizes the importance of interacting dots and electron traps in generating a cohesive picture that encompasses all transport regimes. Overall, our results suggest that CQDs constitute a versatile materials platform for 3D integrated electronic purposes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 3 figures, 1 supplementary file
Investigation of local surrounding of Mn atoms in Ni-Mn-Ga Heusler alloy using nuclear magnetic resonance
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Vojtěch Chlan, Martin Adamec, Oleg Heczko
The local environment of Mn atoms in stoichiometric and off-stoichiometric (with Mn excess) Ni-Mn-Ga Heusler alloys was investigated using Nuclear Magnetic Resonance (NMR) and interpreted with the help of Density Functional Theory (DFT) methods. In cubic austenite, the significant amount of structural defects was observed in $ ^{55}$ Mn NMR experiments and interpreted using DFT calculations as individual antisite defects or defects accompanying anti-phase boundaries. The spectrum of non-modulated martensite was similar to that of austenite, albeit with increasing disorder due to excess Mn. In 10M modulated martensite, the main lines were split. The splitting is ascribed to structural modulation and quantitative analysis shows that the amplitude of modulation evolves with temperature and its magnitude is in agreement with diffraction data.
Materials Science (cond-mat.mtrl-sci)
20 pages, 5 figures
Analysis of real-space transport channels for electrons and holes in halide perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Frederik Vonhoff, Maximilian J. Schilcher, David R. Reichman, David A. Egger
Predicting and explaining charge carrier transport in halide perovskites is a formidable challenge because of the unusual vibrational and electron-phonon coupling properties of these materials. This study explores charge carrier transport in two prototypical halide perovskite materials, MAPbBr$ _3$ and MAPbI$ _3$ , using a dynamic disorder model. Focusing on the role of real-space transport channels, we analyze temporal orbital occupations to assess the impact of material-specific on-site energy levels and spin-orbit coupling (SOC) strengths. Our findings reveal that both on-site energies and SOC magnitude significantly influence the orbital occupation dynamics, thereby affecting charge dispersal and carrier mobility. In particular, energy gaps across on-site levels and the halide SOC strength govern the filling of transport channels over time. This leads us to identify the $ pp\pi$ channel as a critical bottleneck for charge transport and to provide insights into the differences between electron and hole transport across the two materials.
Materials Science (cond-mat.mtrl-sci)
Capillary wave formation in conserved active emulsions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Florian Raßhofer, Simon Bauer, Alexander Ziepke, Ivan Maryshev, Erwin Frey
The dynamics of phase-separated interfaces shape the behavior of both passive and active condensates. While surface tension in equilibrium systems minimizes interface length, non-equilibrium fluxes can destabilize flat or constantly curved interfaces, giving rise to complex interface morphologies. Starting from a minimal model that couples a conserved, phase-separating species to a self-generated chemical field, we identify the conditions under which interfacial instabilities may emerge. Specifically, we show that non-reciprocal chemotactic interactions induce two distinct types of instabilities: a stationary (non-oscillatory) instability that promotes interface deformations, and an oscillatory instability that can give rise to persistent capillary waves propagating along the boundaries of phase-separated domains. To characterize these phenomena, we develop a perturbative framework that predicts the onset, wavelength, and velocity of capillary waves, and quantitatively validate these predictions through numerical simulations. Beyond the linear regime, our simulations reveal that capillary waves undergo a secondary instability, leading to either stationary or dynamically evolving superpositions of different wave modes. Finally, we investigate whether capillary waves can facilitate directed mass transport, either along phase boundaries (conveyor belts) or through self-sustained liquid gears crawling along a solid wall. Taken together, our results establish a general framework for interfacial dynamics in active phase-separating systems and suggest new strategies for controlling mass transport in soft matter and biological condensates.
Soft Condensed Matter (cond-mat.soft)
57 pages, 24 figures
Crystallographic control of hydrogen ingress in bcc-Iron: Insights from ab initio simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Lukas Meier, Asif I. Bhatti, Leo Kestens, Stefaan Cottenier
Hydrogen uptake into body-centered cubic (bcc) iron as a root cause for subsequent hydrogen embrittlement, is initiated at the surface. In this paper, we quantify how readily H diffuses from the surface into the bulk. We consider a set of low-index, vicinal and general Fe surfaces and treat H-permeation as a two-step process. First, density-functional calculations determine the adsorption energy of an isolated H atom at every crystallographically distinct surface site. Second, for each adsorption site we map the minimum-energy pathway that carries the atom beneath the surface and into the lattice. Across all ten orientations studied, a clear trend emerges: sites that bind hydrogen most weakly (highest adsorption energy) are the starting point of the lowest-barrier diffusion channels into the metal interior. Thus, the least-favorable adsorption pockets act as gateways for efficient subsurface penetration. These insights provide a practical design rule: suppressing or minimizing exposure of such high-energy adsorption motifs - through appropriate surface texturing or orientation control - should make bcc-iron components less susceptible to hydrogen uptake and the associated embrittlement.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
26 pages, 12 figures. To be submitted to “International Journal of Hydrogen Energy”
Impact of anharmonicity on the carrier mobility of the Pb-free CsSnBr$_3$ perovskite
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Junwen Yin, Olle Hellman, Samuel Poncé
Charge carrier mobilities are critical parameters in halide perovskite solar cells, governing their average carrier velocity under an applied electric field and overall efficiency. Recent advances in first-principles calculations of electron-phonon interactions and carrier mobilities have enabled predictive computations for perovskite solar cells. However, the flexible octahedral frameworks and cationic displacements in these materials challenge the harmonic approximation, leading to significant difficulties in accurately calculating transport properties. To address these issues, we combine temperature-dependent effective potentials with the ab initio Boltzmann transport equations to compute carrier mobilities in a representative lead-free perovskite, CsSnBr$ _3$ . At room temperature, the electron/hole Hall mobilities in CsSnBr$ _3$ are 106/256 cm$ ^2$ /Vs when neglecting anharmonic effects and 59/145 cm$ ^2$ /Vs when included. This overestimation of the harmonic approximation arises from the neglect of scattering coming from soft modes. We provide a workflow for performing first-principles carrier mobility calculations in anharmonic systems, advancing the predictive modeling of perovskite solar cells.
Materials Science (cond-mat.mtrl-sci)
9 pages and 7 figures
The finite-difference parquet method: Enhanced electron-paramagnon scattering opens a pseudogap
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Jae-Mo Lihm, Dominik Kiese, Seung-Sup B. Lee, Fabian B. Kugler
We present the finite-difference parquet method that greatly improves the applicability and accuracy of two-particle correlation approaches to interacting electron systems. This method incorporates the nonperturbative local physics from a reference solution and builds all parquet diagrams while circumventing potentially divergent irreducible vertices. Its unbiased treatment of different fluctuations is crucial for reproducing the strong-coupling pseudogap in the underdoped Hubbard model, consistent with diagrammatic Monte Carlo calculations. We reveal a strong-coupling spin-fluctuation mechanism of the pseudogap with decisive vertex corrections that encode the cooperation of direct- and exchange-type scattering between electrons and antiferromagnetic spin fluctuations.
Strongly Correlated Electrons (cond-mat.str-el)
Integrability of the Kondo model with time dependent interaction strength
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
In this letter we consider the time dependent Kondo model where a magnetic impurity interacts with the electrons through a time dependent interaction strength $ J(t)$ . Using the Bethe ansatz framework, an exact solution to the time dependent Schrodinger equation is constructed. We show that when periodic boundary conditions are applied, the consistency of the solution results in a constraint equation which relates the amplitudes corresponding to a certain ordering of the particles in the configuration space. This constraint equation takes the form of a matrix difference equation, and the associated consistency conditions restrict the interaction strength $ J(t)$ for the system to be integrable. For a given $ J(t)$ satisfying these constraints, the solution to the matrix difference equations provides the exact many-body wavefunction that satisfies the time-dependent Schrodinger equation. The framework developed in this work is general and provides a method to solve new class of Hamiltonians with time-dependent interaction strength which are based on quantum Yang-Baxter algebra.
Strongly Correlated Electrons (cond-mat.str-el), Mathematical Physics (math-ph)
Auger parameter analysis for TiN and AlN thin films via combined in-situ XPS and HAXPES
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
O.V. Pshyk. J. Patidar, C. Cancellieri, S. Siol
Auger parameter analysis provides in-depth information about the electronic and chemical bonding properties of TiN and AlN thin films, which are relevant across a wide range of technologies. Meaningful interpretation and analysis of the Auger parameter of these materials have been hindered due to, among other reasons, the absence of reliable references. Here we present a comprehensive study of Auger parameters for TiN and AlN thin films using a dual-source lab-based XPS/HAXPES system equipped with Al Ka and Cr Ka x-ray sources. Due to a large spread of excitation x-ray energy, bulk- and surface-sensitive core-level photoelectrons and Auger transitions are probed. This allows us to study a wide range of Auger and core-level emission lines of TiN and AlN. These measurements can serve as references for further identification of chemical state changes, oxidation state or any deviations in the local chemical environment in these materials. UHV sample transfer was employed to minimise surface contamination. Additionally, we demonstrate how common procedures such as ambient air exposure and Ar+ sputter-etching influence the Auger parameters, highlighting the importance of surface preparation in spectroscopic analysis.
Materials Science (cond-mat.mtrl-sci)
28 pages, 6 figure
Many-body localization in a quantum Ising model with the long-range interaction: Accurate determination of the transition point
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-27 20:00 EDT
Illia Lukin, Andrii Sotnikov, Alexander L. Burin
Many-body localization (MBL) transition emerges at strong disorder in interacting systems, separating chaotic and reversible dynamics. Although the existence of MBL transition within the macroscopic limit in spin chains with a short-range interaction was proved rigorously, the transition point is not found yet because of the dramatic sensitivity of the transition point to the chain length at computationally accessible lengths, possible due to local fluctuations destroying localization. Here we investigate MBL transition in the quantum Ising model (Ising model in a transverse field) with the long-range interaction suppressing the fluctuations similarly to that for the second-order phase transitions. We estimate the MBL threshold within the logarithmic accuracy using exact results for a somewhat similar localization problem on a Bethe lattice problem and show that our expectations are fully consistent with the estimate of the transition point using exact diagonalization. In spite of unlimited growing of the critical disorder within the thermodynamic limit, this result offers the opportunity to probe the critical behavior of the system near the transition point. Moreover, the model is relevant for the wide variety of physical systems with the long-range dipole-dipole, elastic or indirect exchange interactions.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
7 pages, 5 figures
Structure and Elastic properties of Titanium MXenes: evaluation of COMB3, REAXFF and MEAM force fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-27 20:00 EDT
Luis F. V. Thomazini, Alexandre F. Fonseca
Titanium carbide and nitride MXenes are two-dimensional inorganic materials that exhibit noteworthy physical and chemical properties. These materials are considered for a variety of technological applications, ranging from energy harvesting to optical and biomedical applications. Given the growing interest in titanium MXenes, there is an expanding demand for computational studies to predict physical properties and behaviors under diverse physical conditions. Complex and large-scale systems necessitate computational methodologies that surpass the constraints imposed by ab initio calculations. In this regard, it is imperative to ascertain the reliability of the computational tools employed to simulate and predict the physical properties of titanium MXenes. In this study, the ability of three known classical molecular dynamics (MD) potentials to provide the structural and elastic properties of titanium carbide and nitride MXenes is evaluated. The MD potentials that were the focus of this study include the Charge-Optimized Many-Body (COMB3), the Reactive Force Field (REAXFF) and the Modified Embedded Atom Method (MEAM). These three potentials possess two or more sets of parameters, herein referred to as force fields, capable of simulating Ti-C and Ti-N systems. The MD results for the lattice parameter and thickness of the MXenes are then compared to those from DFT calculations found in the literature. A total of ten force fields were considered; of these, two REAXFF and two MEAM ones were identified as the most adequate to simulate both the structure and elastic properties of titanium MXenes. Additionally, the values for the linear compressibility of MXenes are presented for the first time. Consequently, researchers can utilize the obtained results to design novel MD-based computational studies of titanium MXenes, leveraging the established relative validity of the available force fields.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
44 pages, 4 figures, 10 tables
Mechanism of defect formation in the quantum annealing of random transverse-field Ising chain
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-27 20:00 EDT
Based on the strong-disorder renormalization group method, a microscopic mechanism of defect formation in the quantum annealing of the random transverse-field Ising chain is proposed, which represents the annealing process as a gradual aggregation of strongly coupled spin clusters. The ferromagnetic ground states of clusters are either preserved or get excited in pairwise fusions of clusters, depending on the effective annealing rate of the fusion, the latter events being responsible for the appearance of defects in the final state. An interesting consequence of the theory is that, although the Griffiths-McCoy phases surrounding the critical point are gapless, these phases are still effectively gapped from the point of view of quantum annealing. Thereby we provide an a posteriori justification of the assumption on the finiteness of gap outside of the critical point tacitly used in earlier works, and also refine the functional form of its vanishing at the critical point. The defect density in the final state is found to decrease with the annealing time $ \tau$ asymptotically as $ n(\tau)\sim \ln^{-2}\left(\frac{\tau}{\ln^2\tau}\right)$ . In addition to this, our approach gives access also to the time-dependent density of defects accumulated during the annealing process at intermediate times.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
10 pages, 3 figures
Floquet engineering spin triplet states in unconventional magnets
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-27 20:00 EDT
Pei-Hao Fu, Sayan Mondal, Jun-Feng Liu, Yukio Tanaka, Jorge Cayao
We consider unconventional magnets with and without spin-singlet $ s$ -wave superconductivity and demonstrate the emergence of spin triplet states due to light drives. In particular, we find that a high-frequency linearly polarized light drive induces a spin-triplet density in $ d$ -wave altermagnets which does not exist in the static regime and can directly reveal the strength of the altermagnetic field. In this high-frequency regime, we also show that linearly polarized light enables the formation of odd-frequency spin-triplet superconducting correlations possessing $ d$ -wave and $ s$ -wave parities, which can be controlled by the light drive and accessed by measuring the spin density. Moreover, for low-frequency linearly and circularly polarized light drives, we obtain that the types of superconducting correlations are broadened due to the presence of Floquet bands, enabling spin-triplet pairs in $ d$ - and $ p$ -wave unconventional magnets, which are absent in the undriven phase.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 5 figures
Universal non-thermal fixed point for quasi-1D Bose gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-27 20:00 EDT
Qi Liang, RuGway Wu, Pradyumna Paranjape, Ben Schittenkopf, Chen Li, Jörg Schmiedmayer, Sebastian Erne
Spatio-temporal scaling dynamics connected to non-thermal fixed points has been suggested as a universal framework to describe the relaxation of isolated far-from-equilibrium systems. Experimental studies in weakly-interacting cold atom systems have found scaling dynamics connected to specific attractors. In our experiments, we study a quantum gas of strongly interacting $ ^6$ Li$ _2$ Feshbach molecules, brought far out of equilibrium by imprinting a white-noise phase profile. The observed relaxation follows the same universal dynamics as for the previously observed formation of the order parameter in a shock-cooled gas of weakly interacting $ ^{87}$ Rb atoms. Our results point to a single universal fixed point with a large basin of attraction governing the relaxation of quasi-1D bosonic systems, independent of their specific initial conditions and microscopic details.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Biaxial characterization of soft elastomers: experiments and data-adaptive configurational forces for fracture
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-27 20:00 EDT
Miguel Angel Moreno-Mateos, Simon Wiesheier, Ali Esmaeili, Mokarram Hossain, Paul Steinmann
Understanding the fracture mechanics of soft solids remains a fundamental challenge due to their complex, nonlinear responses under large deformations. While multiaxial loading is key to probing their mechanical behavior, the role of such loading in fracture processes is still poorly understood. Here, we present a combined experimental-computational framework to investigate fracture in soft elastomers under equi-biaxial loading. We report original equi-biaxial quasi-static experiments on five elastomeric materials, revealing a spectrum of material and fracture behavior, from brittle-like to highly deformable response with crack tip strains exceeding 150 %. Motivated by these observations, we develop a hybrid computational testbed that mirrors the experimental setup and enables virtual biaxial tests. Central to this framework are two components: a data-adaptive formulation of hyperelastic energy functions that flexibly captures material behavior, and a post-processing implementation of the Configurational Force Method, providing a computationally efficient estimate of the J-integral at the crack tip. Our data-adaptive framework for hyperelastic energy functions proves versatility to capture with high accuracy the hyperelastic behavior observed in the biaxial experiments. This is important because accurately capturing the constitutive behaviour of soft solids is key for a reliable application of the Configurational Force Method to soft solids. In the limit of crack onset, a critical value of the crack tip configurational force allows for a criterion of fracture toughness. Together, our experimental, theoretical, and computational contributions offer a new paradigm for characterizing and designing soft materials with tailored fracture properties.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Dynamics of Clusters of Anyons in Fractional Quantum Hall Fluids
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-27 20:00 EDT
Qianhui Xu, Guangyue Ji, Yuzhu Wang, Ha Quang Trung, Bo Yang
We investigates the effective interactions between anyons emerging from either model or realistic bare electron-electron (e-e) interactions in Laughlin and Moore-Read fractional quantum Hall (FQH) fluids. Instead of being purely repulsive or attractive, such anyons display rich dynamics with interesting experimental consequences. Two Laughlin anyons prefer to form bound states with short-range e-e interactions, leading to $ 2e/3$ bunched quasiholes at low temperatures instead of the $ e/3$ quasiholes. In non-Abelian Moore-Read FQH phases, two $ e/4$ quasiholes can fuse into topologically distinct ‘’1’’ or ‘’$ \psi$ ‘’ anyons that are no longer degenerate with realistic two-body e-e interactions. This suggests the possibility to energetically separate and manipulate the two types of anyons by tuning the bare electron-electron interactions. We propose that the recently developed high-resolution STM measurements can be used to probe effective anyon interactions when anyons are clustered together after the tunneling of electrons. The local density of states from various bound states of anyon clusters are simulated for both Abelian and non-Abelian systems with (screened) Coulomb interactions.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 13 figures