CMP Journal 2025-09-08
Statistics
Nature Materials: 2
Nature Physics: 1
arXiv: 64
Nature Materials
Re-entrant phase behaviour of organic semiconductors
Original Paper | Electronic devices | 2025-09-07 20:00 EDT
Zhengxing Peng, Masoud Ghasemi, Jasper J. Michels, Harald Ade
The number of polymeric and small-molecular acceptors for organic photovoltaics has exploded in the past decade. As a result, physical insights and efforts aiming at elucidating the coupling between composition and behaviour are required more than ever. Here we present an encompassing study into the phase behaviour of 55 polymer:small-molecular acceptor blends, pivotal in determining device performance and stability. Many of these exhibit non-trivial behaviour, which cannot be understood by conventional mixing theory. Interestingly, the phase diagrams are subject to variations in glass transition temperature, strongly suggesting an important role of configurational entropy. We present an extended model for the mixing free energy, accounting for a temperature dependence of free volume and configurational freedom. The phase behaviour can be roughly categorized in terms of the ratio of the monomeric volumes of the individual components. The model qualitatively reproduces all experimental observations and poses a viable starting point for assisting development.
Electronic devices, Organic molecules in materials science, Polymers, Solar cells
Molecular engineering of two-dimensional polyamide interphase layers for anode-free lithium metal batteries
Original Paper | Batteries | 2025-09-07 20:00 EDT
Shuo Wang, Yan Wang, Zhaofeng Ouyang, Shitao Geng, Qianyun Chen, Xiaoju Zhao, Bin Yuan, Xiao Zhang, Shanshan Tang, Qiuchen Xu, Peining Chen, Huisheng Peng, Hao Sun
Anode-free lithium (Li) metal batteries are promising candidates for high-performance energy storage applications. Nonetheless, their translation into practical applications has been hindered by the slow kinetics and reversibility of Li plating and stripping on copper foils. Here we report a two-dimensional polyamide (2DPA)/lithiated Nafion (LN) interphase layer for anode-free Li metal batteries. Through molecular engineering, we construct a 2DPA layer with a large conjugated structure and Li-ion adsorption groups that show efficient adsorption, distribution and nucleation of Li ions. 2DPA molecules assembled into two-dimensional sheets are further incorporated with LN to create an ultrathin interphase layer with high-rate, high-capacity Li plating/stripping. These 2DPA/LN layers have higher rate capabilities and maximal energy and power densities compared with alternative polymer interphase layers, enabling the fabrication of an anode-free pouch cell with high performance. Overall, our interphase engineering approach is a promising tool to push the translation of anode-free Li metal batteries based on two-dimensional polymer interphase layers into practical devices, and enable the fabrication of energy storage technologies with high energy and power densities.
Batteries, Polymer chemistry
Nature Physics
Certifying almost all quantum states with few single-qubit measurements
Original Paper | Information theory and computation | 2025-09-07 20:00 EDT
Hsin-Yuan Huang, John Preskill, Mehdi Soleimanifar
Certifying that an n-qubit state synthesized in the laboratory is close to a given target state is a fundamental task in quantum information science. However, existing rigorous protocols applicable to general target states have potentially prohibitive resource requirements in the form of either deep quantum circuits or exponentially many single-qubit measurements. Here we prove that almost all n-qubit target states, including those with exponential circuit complexity, can be certified from only O(n2) single-qubit measurements. Given access to the target state’s amplitudes, our protocol requires only O(n3) classical computation. This result is established by a technique that relates certification to the mixing time of a random walk. Our protocol has applications for benchmarking quantum systems, for optimizing quantum circuits to generate a desired target state and for learning and verifying neural networks, tensor networks and various other representations of quantum states using only single-qubit measurements. We show that such verified representations can be used to efficiently predict highly non-local properties of a synthesized state that would otherwise require an exponential number of measurements on the state. We demonstrate these applications in numerical experiments with up to 120 qubits and observe an advantage over existing methods such as cross-entropy benchmarking.
Information theory and computation, Quantum information
arXiv
Domain coarsening in fractonic systems: a cascade of critical exponents
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-08 20:00 EDT
Jacopo Gliozzi, Federico Balducci, Giuseppe De Tomasi
We study the dynamics of domain growth when multipole moments of the order parameter are conserved. Following a quench into the ordered phase of the Ising model, the typical size of domains grows with time as $ R(t) \sim t^{1/2}$ in the absence of conserved quantities. When the order parameter is conserved, the domain growth slows to $ R(t) \sim t^{1/3}$ . Conservation of higher moments of the order parameter fundamentally modifies this behavior: coarsening proceeds via anomalously slow growth. We analytically and numerically show that conservation of the $ m$ -th multipole moment causes domains to grow as $ R(t) \sim t^{1/(2m+3)}$ . This cascade of dynamical critical exponents characterizes a new family of non-equilibrium universality classes for fractonic systems.
Statistical Mechanics (cond-mat.stat-mech)
12+2 pages, 7+2 figures
Dirac quantum criticality in twisted double bilayer transition metal dichalcogenides
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-08 20:00 EDT
We investigate the phase diagram of moiré double bilayer transition metal dichalcogenides with ABBA stacking as a function of twist angle and applied pressure. At hole filling $ \nu = 2$ per moiré unit cell, the noninteracting system hosts a Dirac semimetal with graphene-like low-energy bands in the moiré Brillouin zone. At small twist angles, the Fermi velocity is reduced and interactions dominate the low-temperature behavior. A strong-coupling analysis identifies insulating ferromagnetic and antiferromagnetic ground-state candidates, characterized by spin-density modulations set by the moiré scale. Using a realistic continuum model with long-range Coulomb interactions, we perform self-consistent Hartree-Fock calculations to study the competition between these states. Varying the twist angle or pressure drives a transition from a Dirac semimetal to an antiferromagnetic insulator, which breaks SU(2) spin rotation and two-fold lattice rotation symmetries. This semimetal-to-insulator transition is continuous and belongs to the (2+1)D relativistic Gross-Neveu-Heisenberg universality class with $ N = 2$ four-component Dirac fermions. Finite heterostrain, relevant in realistic samples, induces a crossover from Gross-Neveu-Heisenberg universality at intermediate temperatures to conventional (2+1)D Heisenberg criticality at the lowest temperatures. Further decreasing the twist angle can cause a level crossing from the antiferromagnetic insulator into a ferromagnetic insulator with spin-split bands. Our results provide a comprehensive theoretical framework that complements and elucidates recent experiments in twisted double bilayer WSe$ _2$ .
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
17 pages, 8 figures
Superconducting pairing symmetries in charge-ordered kagomé metals
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-08 20:00 EDT
Pujita Das, Parth Bahuguna, Tulika Maitra, Narayan Mohanta
We investigate the superconducting state in a kagomé lattice, with intertwined charge order and time-reversal symmetry-breaking loop current, using self-consistent Bogoliubov-de Gennes formalism to find the emergent pairing symmetries. Using local and nearest-neighbor attractive interactions, treated within Hartree-Fock mean-field approximation, we obtain all possible pairing symmetries in position space. Our findings indicate that the uniform $ s$ -wave symmetry, arising in the absence of the charge order and the loop current, modifies to a pair density wave of $ s$ -wave symmetry of 2$ \times$ 2 lattice periodicity in the presence of the charge order, and a chiral pair density wave of $ d_{x^2-y^2}!+!id_{xy}$ -wave symmetry of the same 2$ \times$ 2 periodicity in the presence of the charge order and loop current order, in both onsite and nearest-neighbor channels. In the absence of inversion symmetry, such as in the thin-film geometry, Rashba spin-orbit coupling appears, inducing an additional nearest-neighbor triplet $ p_x\pm ip_y$ -wave pairing. The results are relevant to superconductivity found in $ A$ V$ _{3}$ Sb$ _{5}$ ($ A$ = K, Rb, Cs), coexisting with a charge order that breaks time-reversal symmetry. We discuss fingerprints of these different pairing symmetries in scanning tunneling microscopy experiments.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 10 figures
Symmetric entanglers for non-invertible SPT phases
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
It has been suggested that non-invertible symmetry protected topological phases (SPT), due to the lack of a stacking structure, do not have symmetric entanglers (globally symmetric finite-depth quantum circuits) connecting them. Using topological holography, we argue that a symmetric entangler should in fact exist for $ 1+1$ d systems whenever the non-invertible symmetry has SPT phases connected by fixed-charge dualities (FCD). Moreover, we construct an explicit example of a symmetric entangler for the two SPT phases with $ \mathrm{Rep}(A_4)$ -symmetry, as a matrix product unitary (MPU).
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
8 pages, 1 figure
Non-equilibrium Ion Transport in a Hybrid Battery Material
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
J. Cattermull, B. Jagger, S. J. Cassidy, S. Dhir, P. K. Allan, M. Pasta, A. L. Goodwin
Hybrid materials, which combine inorganic and molecular components, often exhibit structural flexibility that enables unusual functional responses. Among them, Prussian blue analogues (PBAs) are a promising class for post-lithium battery technologies. Here, we show that non-equilibrium transformation processes govern the charge-storage mechanism of a PBA electrode, K2Mn[Fe(CN)6]. Ostensibly, this behavior mirrors that observed in high-rate cycling of conventional cathodes such as LiFePO4, yet arises here for fundamentally different reasons – namely, low elastic moduli and cooperative distortions inherent to the hybrid framework. Using \emph{operando} methods, we show that framework flexibility limits transport kinetics and promotes collective, metastable pathways. Our results highlight new directions for PBA cathode optimisation, but also suggest a broader relevance of non-equilibrium mechanisms for mass transport in hybrid materials beyond PBAs alone.
Materials Science (cond-mat.mtrl-sci)
Exploring the variational method for thermodynamic models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-08 20:00 EDT
This work explores the possibilities of the Gibbs-Bogoliubov-Feynman variational method, aiming at finding room for designing various drawing schemes. For example, mean-field approximation can be viewed as a result of using site-independent drawing in the variational method. In subsequent sections, progressively complex drawing procedures are presented, starting from site-independent drawing in the $ k$ -space. In the next, each site in the real-space is again drawn independently, which is followed by an adjustable linear transformation $ T$ . Both approaches are presented on the discrete Ginzburg-Landau model. Subsequently, a percolation-based procedure for the Ising model is developed. It shows a general way of handling multi-stage drawing schemes. Critical inverse temperatures are obtained in two and three dimensions with a few percent discrepancy from exact values. Finally, it is shown that results in the style of the real-space renormalization group can be achieved by suitable fractal-like drawing. This facilitates a new straight-forward approach to establishing the renormalization transformation, but primarily provides a new view on the method. While the first two approaches are capable of capturing long-range correlations, they are not able to reproduce the critical behavior accurately. The main findings of the paper are developing the method of handling intricate drawing procedures and identifying the need of fractality in these schemes to grasp the critical behavior.
Statistical Mechanics (cond-mat.stat-mech)
Physica A: Statistical Mechanics and its Applications, 2025, 130941, ISSN 0378-4371
Tuning Nonradiative Recombination via Cation Substitution in Inorganic Antiperovskite Nitrides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Sanchi Monga, Saswata Bhattacharya
Inorganic antiperovskite nitrides have recently emerged as promising materials for photovoltaic applications, yet their nonradiative recombination dynamics remain largely unexplored. Here, we examine the influence of X-site cation substitution on the nonradiative electron-hole recombination in $ \mathrm{X_{3}NSb}$ ($ X = \mathrm{Ca}, \mathrm{Sr}, \mathrm{Ba}$ ). Ca- and Sr-based compounds adopt a cubic phase, whereas Ba stabilizes in a hexagonal structure, introducing pronounced symmetry-driven effects. Substituting Ca with Sr narrows the band gap, suppresses octahedral and band-edge fluctuations, reduces nonadiabatic (NA) coupling by $ \sim 54%$ , and extends carrier lifetimes by a factor of $ 2.5$ . In contrast, Ba substitution increases lattice distortion, widens the band gap, and enhances NA coupling beyond that of $ \mathrm{Sr_{3}NSb}$ , thereby accelerating recombination through stronger lattice fluctuations. The resulting band gap fluctuations in $ \mathrm{Ba_{3}NSb}$ also shorten decoherence times, following the trend $ \mathrm{Ba_{3}NSb} < \mathrm{Ca_{3}NSb} < \mathrm{Sr_{3}NSb}$ . Our results demonstrate how the interplay between band gap, NA coupling, and decoherence time governs recombination lifetimes, with $ \mathrm{Sr_{3}NSb}$ exhibiting the longest lifetime. These findings highlight the coupled influence of cation chemistry and crystal symmetry in tailoring carrier dynamics for high-performance antiperovskite-based optoelectronics materials.
Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Strongly Entangled Kondo and Kagome Lattices and the Emergent Magnetic Ground State in Heavy-Fermion Kagome Metal YbV$_6$Sn$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
Rui Lou, Max Mende, Riccardo Vocaturo, Hao Zhang, Qingxin Dong, Man Li, Pengfei Ding, Erjian Cheng, Zhiguang Liao, Yu Zhang, Junfa Lin, Reza Firouzmandi, Vilmos Kocsis, Laura T. Corredor, Yurii Prots, Oleksandr Suvorov, Anupam Jana, Jun Fujii, Ivana Vobornik, Oleg Janson, Wenliang Zhu, Jeroen van den Brink, Cornelius Krellner, Minghu Pan, Bosen Wang, Tianlong Xia, Jinguang Cheng, Shancai Wang, Claudia Felser, Bernd Büchner, Sergey Borisenko, Rong Yu, Denis V. Vyalikh, Alexander Fedorov
Applying angle-resolved photoemission spectroscopy and density functional theory calculations, we present compelling spectroscopic evidence demonstrating the intertwining and mutual interaction between the Kondo and kagome sublattices in heavy-fermion intermetallic compound YbV$ _6$ Sn$ _6$ . We reveal the Yb 4$ f$ -derived states near the Fermi level, along with the presence of bulk kagome bands and topological surface states. We unveil strong interactions between the 4$ f$ and itinerant electrons, where the kagome bands hosting the Dirac fermions and van Hove singularities predominate. Such findings are well described using a $ c$ -$ f$ hybridization model. On the other hand, our systematic characterization of magnetic properties demonstrates an unusually enhanced antiferromagnetic ordering, where the kagome-derived van Hove singularities near $ E_F$ play a vital role in determining the unconventional nature of the Ruderman-Kittel-Kasuya-Yosida interaction and Kondo coupling. These unique kagome-state-mediated exchange interactions have never been reported before and could lead to a novel phase diagram and various quantum critical behaviors in YbV$ _6$ Sn$ _6$ and its siblings. Our results not only expand the family of exotic quantum phases entangled with kagome structure to the strongly correlated regime, but also establish YbV$ _6$ Sn$ _6$ as an unprecedented platform to explore unconventional many-body physics beyond the standard Kondo picture.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
8 pages, 4 figures, Phys. Rev. Lett. in press
Active Heat Transfer Fluids (AHTF): Enhancement of Convective Heat Transfer by Bubble-Driven Self-Propelled Microparticles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-08 20:00 EDT
Jacob Velazquez, Pawel Keblinski, Jeffrey Moran
Liquid coolants containing conductive nanoparticles (nanofluids) have been widely studied over the past 30 years but have seen limited adoption in real-world cooling applications. The ability of passive nanoparticles to enhance heat transfer in liquids is fundamentally limited because the nanoparticles cannot move on their own relative to the bulk fluid, and thus generate negligible convective enhancements in heat transport. In this work, we present experimental evidence that micron-scale self-propelled particles, which convert chemical energy into autonomous motion, enhance convective heat transfer in liquids. We quantified this enhancement by measuring the convective heat transfer coefficient in a pool of suspension heated from below. The enhancements associated with self-propulsion are most pronounced at low heating powers (Rayleigh number of 10,000), in which case the heat transfer coefficient can be over 100 percent higher in the self-propelled case compared to the same particles without propulsion. This work provides a proof-of-concept demonstration that active particles can enhance heat transfer in liquids, motivating the development of “Active Heat Transfer Fluids” for various cooling applications.
Soft Condensed Matter (cond-mat.soft)
35 pages, 9 figures, 3 tables
Mo Atom Rearrangement Drives Layer-Dependent Reactivity in Two-Dimensional MoS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Zifan Wang, Jiaxuan Wen, Tina Mihm, Shaopeng Feng, Kelvin Huang, Jing Tang, Tianshu Li, Liangbo Liang, Sahar Sharifzadeh, Keji Lai, Xi Ling
Two-dimensional (2D) materials offer a valuable platform for manipulating and studying chemical reactions at atomic level, owing to the ease of controlling their microscopic structure at the nanometer scale. While extensive research has been conducted on the structure-dependent chemical activity of 2D materials, the influence of structural transformation during the reaction remains largely unexplored. In this work, we report the layer-dependent chemical reactivity of MoS2 during a nitridation atomic substitution reaction and attribute it to the rearrangement of Mo atoms. Our results show that the chemical reactivity of MoS2 decreases as the number of layers is reduced in the few-layer regime. In particular, monolayer MoS2 exhibits significantly lower reactivity compared to its few-layer and multilayer counterparts. Atomic-resolution transmission electron microscope (TEM) reveals that MoN nanonetworks form as reaction products from monolayer and bilayer MoS2, with the continuity of the MoN crystals increasing with layer number, consistent with the local conductivity mapping data. The layer-dependent reactivity is attributed to the relative stability of the hypothetically formed MoN phase which retain the number of Mo atomic layers present in the precursor. Specifically, the low chemical reactivity of monolayer MoS2 is attributed to the high energy cost associated with Mo atom diffusion and migration necessary to form multi-layer Mo lattices in the thermodynamically stable MoN phase. This study underscores the critical role of lattice rearrangement in governing chemical reactivity and highlights the potential of 2D materials as versatile platforms for advancing the understanding of materials chemistry at atomic scale.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
41 pages, 20 figures
A generalized and adaptable tensor-contraction-based cluster expansion formalism for multicomponent solids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Jacob Jeffries, Bochuan Sun, Enrique Martinez
Density functional theory (DFT)-based simulations of materials have first-principles accuracy, but are very computationally expensive. For simulating various properties of multi-component alloys, the cluster expansion (CE) technique has served as the standard workaround to improve computational efficiency. However, the standard CE technique is difficult to extend to exotic and/or low-symmetry lattices, often implemented via iteration over particular cluster types, which must be enumerated per lattice structure. In this work, we introduce the tensor cluster expansion (TCE), implemented in the open-source code tce-lib, which maps correlation functions to mixed tensor contractions, eliminating the need to iterate over cluster types and additionally making the calculation of correlation functions well-suited for massively parallel architectures like GPUs. We show that local interaction energies are an immediate consequence of the TCE formalism, yielding nearly $ \mathcal{O}(1)$ energy difference calculations. We then use this formalism to fit CE models for the TaW and CoNiCrFeMn systems, and use these models to respectively compute the enthalpy of mixing curve and Cowley short-range order parameters, showing excellent agreement with ground truth data.
Materials Science (cond-mat.mtrl-sci)
16 pages, 7 figures
Emergent odd viscoelasticity in chiral soft glassy materials
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-08 20:00 EDT
Debarghya Banerjee, Peter Sollich
Rheological properties of chiral active materials have been an important area of research in the recent past, in particular regarding odd terms in their mechanical response. While much progress has been made in the study of odd viscous fluids and odd elastic solids, there is still a lack of understanding of odd viscoelastic responses. We introduce a chiral soft glassy rheology model to understand the emergence and nature of such odd viscoelastic responses in a class of amorphous solids. We use this model, which effectively considers an ensemble of actively rotating inclusions in a glassy matrix, to study the linear stress response to steady and oscillatory shear flows. For steady shear we find an odd viscosity that, non-trivially, grows as the active rotation frequency {\Omega} decreases. In oscillatory shear we find an odd viscoelastic spectrum with a non-trivial dependence on the driving frequency {\omega}, combining resonance effects around {\omega} = 2{\Omega} with glassy power laws at larger {\omega}.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
A Fully Discrete Element Approach for Modeling Vacuum Packed Particle Dampers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Pawel Chodkiewicz, Robert Zalewski, Jakub Lengiewicz
In this work, we investigate Vacuum-Packed Particle (VPP) dampers – granular-core dampers offering tunable damping performance – as a more sustainable alternative to conventional systems such as magnetorheological fluid dampers. A comprehensive computational model of the entire VPP damper system is developed using the Discrete Element Method (DEM). A novel discrete-element model of the flexible foil, responsible for consistently transmitting the external pressure resulting from vacuum application, is introduced and implemented by extending the open-source Yade DEM framework. A prototype VPP damper is also designed and experimentally tested, enabling both model calibration and validation of the simulation results. The calibrated DEM model is subsequently employed in a parametric study to assess the influence of material, geometrical, and process parameters on damper performance. All code, along with the associated experimental and simulation datasets, is made available in an open-access repository.
Materials Science (cond-mat.mtrl-sci)
Thermoelectric transport in graphene under strain fields modeled by Dirac oscillators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-08 20:00 EDT
Juan A. Cañas, Daniel A. Bonilla, A. Martín-Ruiz
Graphene has emerged as a paradigmatic material in condensed matter physics due to its exceptional electronic, mechanical, and thermal properties. A deep understanding of its thermoelectric transport behavior is crucial for the development of novel nanoelectronic and energy-harvesting devices. In this work, we investigate the thermoelectric transport properties of monolayer graphene subjected to randomly distributed localized strain fields, which locally induce impurity-like perturbations. These strain-induced impurities are modeled via 2D Dirac oscillators, capturing the coupling between pseudorelativistic charge carriers and localized distortions in the lattice. Employing the semiclassical Boltzmann transport formalism, we compute the relaxation time using a scattering approach tailored to the Dirac oscillator potential. From this framework, we derive analytical expressions for the electrical conductivity, Seebeck coefficient, and thermal conductivity. The temperature dependence of the scattering centers density is also investigated. Our results reveal how strain modulates transport coefficients, highlighting the interplay between mechanical deformations and thermoelectric performance in graphene. This study provides a theoretical foundation for strain engineering in thermoelectric graphene-based devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Accepted in Physical Review B
A Review on Molecular Simulations for the Rupture of Polymer Networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-08 20:00 EDT
Yuichi Masubuchi, Takato Ishida, Yusuke Koide, Takashi Uneyama
Molecular simulations provide a powerful means to unravel the complex relationships between network architecture and the mechanical response of polymer networks, with a particular emphasis on rupture and fracture phenomena. Although simulation studies focused on polymer network rupture remain relatively limited compared to the broader field, recent advances have enabled increasingly nuanced investigations that bridge molecular structures and macroscopic failure behaviors. This review surveys the evolution of molecular simulation approaches for polymer network rupture, from early studies on related materials to state-of-the-art methods. Key challenges, including mismatched spatial and temporal scales with experiments, the validity of coarse-grained models, the choice of simulation protocols and boundary conditions, and the development of meaningful structural descriptors, are critically discussed. Special attention is paid to the assumptions underlying universality, limitations of current methodologies, and the ongoing need for theoretically sound and experimentally accessible network characterization. Continued progress in computational techniques, model development, and integration with experimental insights will be essential for a deeper, predictive understanding of polymer network rupture.
Soft Condensed Matter (cond-mat.soft)
20 pages, 4 figures
$^{51}$V NMR evidence for interlayer-modulated charge order and a first-order low-temperature transition in CsV$_3$Sb$_5$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
Xiaoling Wang, Arneil P. Reyes, Hrishit Banerjee, Andrea N. Capa Salinas, Stephen Wilson, Brenden R. Ortiz
Charge order in the kagome superconductor CsV$ _3$ Sb$ 5$ exhibits a complex three-dimensional organization and intermediate-temperature anomalies whose bulk character has remained unsettled. We use orientation-dependent $ ^{51}$ V NMR as a site-selective probe to determine the stacking of the charge density wave (CDW) state and its thermal evolution. Below $ T{\mathrm{CDW}}!\approx!94$ ~K, the field-linear splitting of the $ ^{51}$ V central transition together with the anisotropy of the Knight-shift tensor identify an interlayer-modulated $ 3\mathbf{q}$ CDW whose local environments are consistent with a four-layer $ 2\times2\times4$ stacking with mixed trihexagonal/Star-of-David distortions, in agreement with synchrotron x-ray determinations. For comparison, RbV$ _3$ Sb$ _5$ serves as a reference exhibiting a uniform trihexagonal $ 2\times2\times2$ stacking, allowing us to isolate features unique to the $ 2\times2\times4$ state in CsV$ _3$ Sb$ 5$ . With $ \mathbf{H}0!\parallel!c$ , the $ ^{51}$ V quadrupolar satellites through the intermediate temperature scale near $ T{\mathrm{CO}}!\approx!65$ K reorganize into two well-resolved electric-field-gradient manifolds that coexist over a finite interval; their relative spectral weights interchange on cooling while the total integrated satellite intensity remains conserved and $ \nu_Q$ within each manifold is nearly temperature independent. The coexistence without critical broadening, together with conserved intensity, provides bulk evidence consistent with a first-order charge-order transition near $ T{\mathrm{CO}}$ . Our measurements do not resolve whether this lower-temperature transition corresponds to a distinct in-plane order or a reorganization of the $ 3\mathbf{q}$ state; rather, they delimit this window and provide bulk, site-resolved constraints that connect prior reported anomalies to a thermodynamic first-order transition.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Temperature dependence of $p$-wave contacts in a harmonically trapped Fermi gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-08 20:00 EDT
Kenta Nagase, Hikaru Takahashi, Soki Oshima, Takashi Mukaiyama
We study the dependence of the $ p$ -wave contact $ C_v$ on the Fermi temperature $ T_F$ and reduced temperature $ T/T_F$ based on the number of closed-channel molecules. From the anisotropic pattern of dissociated molecules, we resolve the narrow $ |m|=0$ and $ |m|=1$ dipolar splitting of the $ p$ -wave Feshbach resonance in $ ^6$ Li, enabling the independent determination of the contact for the two components. As $ T_F$ increases, the anisotropy is no longer resolved and the near-resonant contact scales linearly with $ \sqrt{T_F}$ , indicating the contribution of the normalized effective range $ k_F R_{\rm{e}}$ . The $ T/T_F$ dependence across the attractive regime reveals opposite trends in the strongly and weakly interacting limits, which are accurately represented by the second-order virial expansion. Our results, together with estimates from the $ p$ -wave virial coefficient, provide a route toward a complete understanding of the thermodynamics of strongly interacting $ p$ -wave Fermi gases.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
7 pages, 5 figures
Surface reconstruction and orthogonal decoupling in SrAl4 and EuAl4
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Tongrui Li, Leiyuan Chen, Jian Yuan, Zhengtai Liu, Yichen Yang, Zhicheng Jiang, Jianyang Ding, Jiayu Liu, Jishan Liu, Zhe Sun, Yanfeng Guo, Tong Zhang, Dawei Shen
Surface-induced symmetry breaking in quantum materials can stabilize exotic electronic phases distinct from those in the bulk, yet its momentum-space manifestations remain elusive due to domain-averaging effects. Here, using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM), we present a microscopic investigation of the electronic structures of SrAl4 and EuAl4, layered tetragonal intermetallic compounds that exhibit well-characterized incommensurate charge-density-wave (CDW) transitions. Below the CDW transition temperatures, we uncover linearly dispersing electronic states and pronounced unidirectional replica bands orthogonal to the bulk CDW wave vector, evidencing the emergence of an in-plane C4 symmetry-breaking electronic order that is not dictated by the bulk incommensurate CDW. STM measurements further reveal a 1 times 2 surface reconstruction with quasi-one-dimensional modulations and half-unit-cell steps, traced to ordered 50 percent Sr/Eu vacancies, which vanish irreversibly upon thermal cycling, indicating decoupled surface and bulk orders. These findings establish SrAl4 and EuAl4 as model platforms for exploring surface-confined nematicity and emergent low-dimensional phases in quantum materials.
Materials Science (cond-mat.mtrl-sci)
9 pages,4 figures
The Three-Body Limit Cycle: Universal Form for General Regulators
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-08 20:00 EDT
Langxuan Chen, Feng Wu, Xincheng Lin, Sebastian König, Ubirajara van Kolck, Pengfei Zhang
The Efimov effect, a remarkable realization of discrete scale invariance, emerges in the three-body problem with short-range interactions and is understood as a renormalization group (RG) limit cycle within Short-Range Effective Field Theory (SREFT). While the analytic form of the three-body renormalization relation has been established for a sharp cutoff regulator, its universality for other regulators remains underexplored. In this letter, we derive the universal functional form of the three-body renormalization relation for general separable regulators through a detailed analysis of the Skorniakov-Ter-Martirosian and Faddeev equations. We find that the relation is characterized by three parameters. This universality is verified numerically for various regulators. Although the functional form remains the same, the parameters characterizing the limit cycle exhibit regulator dependence. These findings broaden the class of RG limit cycles in SREFT and offer a more complete understanding of three-body renormalization.
Quantum Gases (cond-mat.quant-gas), Nuclear Theory (nucl-th), Atomic Physics (physics.atom-ph)
9 pages, 3 figures
Glassy interphases reinforce elastomeric nanocomposites by enhancing percolation-driven volume expansion under strain
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-08 20:00 EDT
Pierre Kawak, Harshad Bhapkar, David S. Simmons
For nearly a century, introduction of nanoparticles to elastomers has yielded extraordinarily tough nanocomposites that are critical to technologies from actuators to tires. The mechanisms by which this reinforcement occurs have nevertheless remained a central open question in material science. One widely debated hypothesis posits that strong interactions between polymer and particles induce “glassy bridges” that cement particles into a cohesive percolating network that resists elongation. Here, molecular dynamics simulations show that glassy particle shells do not primarily provide elongational cohesion. Instead, they amplify an underlying mechanism wherein competition between filler and elastomer networks causes the elastomer’s volume to increase on deformation. This induces contributions from the elastomer’s bulk modulus, which is of order 1000 times larger than its Young’s modulus. These findings establish a unified understanding of low-strain reinforcement in filled elastomers as emanating from volumetric competition between coexisting particulate and elastomeric networks. This reframes and unifies our understanding of low-strain reinforcement, provides a clear-cut diagnostic for the presence of glassy bridging, and offers a new design principle for tough elastomeric nanocomposites.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
Ferrodark soliton collisions: breather formation, pair reproduction and spin-mass separation
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-08 20:00 EDT
Yixiu Bai, Jiangnan Biguo, Xiaoquan Yu
We study collisions between a ferrodark soliton (FDS) and an antiFDS ($ Z_2$ kinks in the spin order) in the easy-plane phase of spin-1 Bose-Einstein condensates (BEC). For a type-I pair (type-I FDS-antiFDS pair) at low incoming velocities, the pair annihilates followed by the formation of an extremely long-lived dissipative breather on a stable background, a spatially localized wave packet with out-of-phase oscillating magnetization and number densities. Periodic emissions of spin and density waves cause breather energy dissipation and we find that the breather energy decays logarithmically in time. When the incoming velocity is larger than a critical velocity at which a stationary FDS-anti FDS pair forms, a pair with finite separating velocity is reproduced. When approaching the critical velocity from below, we find that the lifetime of the stationary type-I pair shows a power-law divergence, resembling a critical behavior. In contrast, a type-II pair (type-II FDS-antiFDS pair)never annihilates and only exhibits reflection. For collisions of a mixed type FDS-antiFDS pair, as $ Z_2$ kinks in the spin order, reflection occurs in the topological structure of the magnetization while the mass superfluid density profiles pass through each other, manifesting spin-mass separation.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS)
4 + 4 pages, 4+4 figures
Active Learning of A Crystal Plasticity Flow Rule From Discrete Dislocation Dynamics Simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Nicholas Huebner Julian, Giacomo Po, Enrique Martinez, Nithin Mathew, Danny Perez
Continuum-scale material deformation models, such as crystal plasticity, can significantly enhance their predictive accuracy by incorporating input from lower-scale (i.e., mesoscale) models. The procedure to generate and extract the relevant information is however typically complex and ad hoc, involving decision and intervention by domain experts, leading to long development times. In this study, we develop a principled approach for calibration of continuum-scale models using lower scale information by representing a crystal plasticity flow rule as a Gaussian process model. This representation allows for efficient parameter space exploration, guided by the uncertainty embedded in the model through a process known as Bayesian optimization. We demonstrate a semi-autonomous Bayesian optimization loop which instantiates discrete dislocation dynamics simulations whose initial conditions are automatically chosen to optimize the uncertainty of a model crystal plasticity flow rule. Our self-guided computational pipeline efficiently generated a dataset and corresponding model whose error, uncertainty, and physical feature sensitivities were validated with comparison to an independent dataset four times larger, demonstrating a valuable and efficient active learning implementation readily transferable to similar material systems.
Materials Science (cond-mat.mtrl-sci)
Enhancement of spin-wave nonreciprocity and group velocity in a low-wavenumber regime
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Shion Yoshimura (1), Shugo Yoshii (1,2), Ryo Ohshima (1,3), Masashi Shiraishi (1,3) ((1) Kyoto Univ., (2) Imperial College London, (3) CSRN, Kyoto Univ)
Nonreciprocity of spin waves is essential for components such as magnetic isolators and circulators used in spin-wave-based computing. A ferromagnetic (FM) bilayer exhibits significant frequency nonreciprocity and has attracted attention in recent years. Prior research on bilayers has predominantly focused on the high-wavenumber regime, where spin waves display significant nonreciprocity and are accessible through Brillouin light scattering (BLS). However, the dynamics at low wavenumbers (k < 5 rad/um), which enable rapid magnon propagation, have yet to be thoroughly investigated. We investigate spin-wave propagation in the bilayer using coplanar waveguides (CPWs) and demonstrate that increasing the bilayer thickness enhances nonreciprocity even at low wavenumbers, which leads to the high group velocity originating from the Damon-Eshbach (DE) mode. These findings establish design principles for high-speed, low-loss spin-wave-based information processing.
Materials Science (cond-mat.mtrl-sci)
17 pages, 5 figures, 1 table
Dynamical crossover between stretched- and compressed-exponential relaxation in a photoexcited crystal
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
Tyler Carbin, Joel Herman, Xinshu Zhang, Adrian B. Culver, Yu Zhang, Hengdi Zhao, Rahul Roy, Gang Cao, Anshul Kogar
Anomalous relaxation is one of the hallmarks of disordered systems. Following perturbation by an external source, many glassy, jammed and amorphous systems relax as a stretched or compressed exponential as a function of time. However, despite their ubiquity, the origins of and the connection between these phenomenological relaxation functions remains to be understood. Here, we observe a tunable crossover from stretched- to compressed-exponential relaxation by photoexciting single crystal Ca3Ru2O7 across a structural phase transition. We present a simple lattice model that shows how spatial inhomogeneity and local, strain-mediated interactions cooperate to produce the dynamical crossover. Our work reveals anomalous relaxation dynamics in an idealized single crystal material and establishes photoexcited solids as promising platforms for probing the mechanisms underlying anomalous relaxation.
Strongly Correlated Electrons (cond-mat.str-el), Soft Condensed Matter (cond-mat.soft)
Low-frequency interlayer phonon dynamics and photoinduced terahertz absorption in black phosphorus
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
Haiyun Huang, Cheng Chen, Yuxin Zhai, Xiu Zhang, Junzhi Zhu, Junyong Wang, Kai Zhang, Qihua Xiong, Haiyun Liu
The strong interlayer coupling in black phosphorus (BP), arising from wavefunction overlap between layers, is critical for understanding its electronic and optical properties. Here, we utilize terahertz (THz) spectroscopy to study phonon dynamics in BP. We identify two peaks at 6 and 8.5 meV in steady-state THz spectra, which are attributed to low-frequency interlayer phonon modes. Both modes exhibit anharmonic phonon coupling behavior below 150 K, manifesting as temperature-dependent red-shifts. Using time-resolved THz spectroscopy, we observe significantly increased THz absorption under photoexcitation, arising from the transient enhancements of the extended Drude component and the oscillator strengths of interlayer phonons in non-equilibrium. These findings highlight the critical role of interlayer phonon dynamics in understanding many-body physics in BP.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
16 pages, 4 figures
Optics Express Vol. 33, Issue 18, pp. 37748-37758 (2025)
Universal properties and dynamical bosonization of strongly interacting one-dimensional $p$-wave anyons
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-08 20:00 EDT
We study a one-dimensional system of strongly interacting anyons with short-range interactions under external confinement. This system, referred to as $ p$ -wave anyons, interpolates continuously between spin-polarized fermions with $ p$ -wave interactions and free bosons. At zero temperature, the correlation functions decay exponentially with distance, with oscillations governed by the statistics parameter. The decay rate is maximal for $ p$ -wave fermions and decreases monotonically as the statistics parameter approaches the bosonic limit, where it vanishes. The momentum distribution is asymmetric, a hallmark of one-dimensional anyons, and takes the form of a shifted Lorentzian with universal power-law tails, $ \lim_{k \to \pm \infty} n(k)\sim C/k^2$ . We prove analytically that, following release from a harmonic trap, the asymptotic momentum distribution converges to that of free bosons in the same trap, a phenomenon known as dynamical bosonization. We also establish the universality of the groundstate $ n$ -particle reduced density matrices: their natural occupations are independent of the confining potential, while the associated natural $ n$ -functions for different confinements are related through a simple analytical transformation. In particular, for the one-particle reduced density matrix, we derive exact expressions for both the natural occupations and the natural orbitals at arbitrary particle number. These results extend and unify earlier partial findings for $ p$ -wave fermions, and they provide a clear conceptual explanation of the double degeneracy observed in their spectrum.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech)
16 pages, 3 figures, RevTeX 4.2
Equal-spin and oblique-spin crossed Andreev reflections in ferromagnet/Ising superconductor/ferromagnet junction
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-08 20:00 EDT
Wei-Tao Lu, Qing-Feng Sun, Qiang Cheng
We study the subgap transport through a ferromagnet/Ising superconductor/ferromagnet (F/ISC/F) junction by solving the Bogoliubov-de Gennes equations. It is found that the crossed Andreev reflection (CAR) and local Andreev reflection (LAR) strongly depend on the spin polarized F, the magnetization direction, and the Ising superconducting phase. For the same magnetization directions of the two F leads, the equal-spin CAR could take place due to spin-flip mechanism induced by the Ising spin-orbit coupling and equal-spin-triplet pairing. Both equal-spin CAR and equal-spin LAR exhibit a remarkable magnetoanisotropy with period \pi and show oscillatory behavior with chemical potential. The equal-spin CAR is more prominent for half-metal F and double-band ISC while the normal CAR is completely suppressed. When the magnetization directions of the two F leads are different, the oblique-spin CAR occurs and its magnetoanisotropic period generally becomes 2\pi instead of \pi. In the oblique-spin CAR process, the spins of the electron and hole are neither parallel nor antiparallel. Furthermore, the property of oblique-spin CAR is very sensitive to the spin and valley degrees of freedom. The spin and valley polarized CAR can be achieved and controlled by the chemical potentials and the magnetization directions.
Superconductivity (cond-mat.supr-con)
Physical Review B 105, 125425 (2022)
Cone-dependent retro and specular Andreev reflections in AA-stacked bilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-08 20:00 EDT
We theoretically study the Andreev reflection (AR) in AA-stacked bilayer graphene/superconductor (AABG/SC) junction. AABG has a linear gapless energy band with two shifted Dirac cones and the electronic states are described by the cone indices. The results indicate that the property of AR strongly depends on the cone degree of freedom. In the absence of the inter-layer potential difference, only intra-cone AR and normal reflection (NR) could occur, and the inter-cone process is forbidden. By adjusting the potential, the intra-cone AR can be specular AR (SAR) in one cone and it is retro-AR (RAR) in the other cone. The existence of the inter-layer potential difference would lead to the inter-cone scattering. As a result, double ARs and double NRs can take place between the two cones. The inter-cone SAR could happen in a broad potential region. Furthermore, the inter-cone retro-NR (RNR) could happen as well. The switch between SAR and RAR, and the switch between specular NR (SNR) and RNR can be achieved by regulating the potential. Therefore, different cone carriers can be separated spatially based on the RAR and SAR. The cone-dependent Andreev conductance may be separately measured near the critical values where RAR crosses over to SAR.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Physical Review B 108, 195425 (2023)
Dislocation interaction with a tilt low angle grain boundary in bi-crystal SrTiO3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Kuan Ding, Atsutomo Nakamura, Patrick Cordier, Xufei Fang
For potentially wider applications of ceramics with dislocation-tuned mechanical and functional properties, it is pertinent to achieve dislocation engineering in polycrystalline ceramics. However, grain boundaries (GBs) in general are effective barriers for dislocation glide and often result in crack formation when plastic deformation in ceramics is attempted at room temperature. To develop strategies for crack suppression, it is critical to understand the fundamental processes for dislocation-GB interaction. For this purpose, we adopt here a model system of bi-crystal SrTiO3 with a 4° tilt GB, which consists of an array of edge dislocations. Room-temperature Brinell indentation was used to generate a plastic zone at the mesoscale without crack formation, allowing for direct assessment of GB-dislocation interaction in bulk samples. Together with dislocation etch pits imaging and transmission electron microscopy analysis, we observe dislocation pileup, storage, and transmission across the low-angle tilt GB. Our experimental observations reveal new insight into dislocation-GB interaction at room temperature at the mesoscale.
Materials Science (cond-mat.mtrl-sci)
Ultrafast Dynamics of Spin-Orbit Entangled Excitons Coupled to Magnetic Ordering in van der Waals Antiferromagnet NiPS3
New Submission | Other Condensed Matter (cond-mat.other) | 2025-09-08 20:00 EDT
Sidhanta Sahu, Anupama Chauhan, Poulami Ghosh, Sayan Routh, Ruturaj Puranik, Setti Thirupathaiah, Siddhartha Lal, Shriganesh Prabhu S, Chiranjib Mitra, N. Kamaraju
Spin-orbit entangled excitons (SOEE) in two-dimensional (2D) antiferromagnets provide a direct access to explore unconventional many body interactions in correlated electron systems. In this work, we carry out a detailed investigation using non-degenerate isotropic and anisotropic pump-probe reflection spectroscopy to probe the ultrafast dynamics of SOEE and their coupling to spin fluctuations in NiPS3. Transient reflectivity data reveals acoustic phonon oscillations at ~ 27 GHz, along with two distinct relaxation timescales: fast (1-9 ps) and slower components (1-4 ns) associated with SOEE coherence and spin reordering, respectively. Both timescales exhibit pronouns temperature dependence near the exciton dissociation (TED = 120 K) and Neel TN = 155 K) temperatures. The SOEE coherence shortens from ~ 8-9 ps at T < TED to ~ 3 ps at T > TED with a finite tail persisting beyond TN. The spin reordering time grows near 120 K, and shows critical slowing down around TN. Pump fluence studies further corroborate their spin origin. Our findings uncover the direct interplay between the excitonic and spin degrees of freedom across ultrafast and longer timescales, offering new opportunities to probe and engineer emergent many-body interactions in 2D antiferromagnets.
Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
28 pages, 22 figures
Coexisting Kagome and Heavy Fermion Flat Bands in YbCr$_6$Ge$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
Hanoh Lee, Churlhi Lyi, Taehee Lee, Hyeonhui Na, Jinyoung Kim, Sangjae Lee, Younsik Kim, Anil Rajapitamahuni, Asish K. Kundu, Elio Vescovo, Byeong-Gyu Park, Changyoung Kim, Charles H. Ahn, Frederick J. Walker, Ji Seop Oh, Bo Gyu Jang, Youngkuk Kim, Byungmin Sohn, Tuson Park
Flat bands, emergent in strongly correlated electron systems, stand at the frontier of condensed matter physics, providing fertile ground for unconventional quantum phases. Recent observations of dispersionless bands at the Fermi level in kagome lattice open the possibility of unifying the disjoint paradigms of topology and correlation-driven heavy fermion liquids. Here, we report the unprecedented coexistence of these mechanisms in the layered kagome metal YbCr6Ge6. At high temperatures, an intrinsic kagome flat band-arising from the frustrated hopping on the kagome lattice-dominates the Fermi level. Upon cooling, localized Yb 4f-states hybridize with the topological kagome flat bands, transforming this state into the Kondo resonance states that are nearly dispersionless across the entire Brillouin zone. Crystalline symmetry forbids hybridization along specific high-symmetry lines, which stabilizes Dirac crossings of heavy-fermion character. Topological analysis of the resulting gaps reveals both trivial and nontrivial Z2 invariants, establishing the emergence of a Dirac-Kondo semimetal phase. Taken together, these results identify YbCr6Ge6 as a prototype of a topological heavy-fermion system and a platform where geometric frustration, strong correlations, and topology converge, with broad implications for correlated quantum matter.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Flux-flow in multiband FeSe$x$Te${1-x}$ explored by microwave magnetotransport
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-08 20:00 EDT
A. Magalotti, A. Alimenti, V. Braccini, P. Manfrinetti, E. Silva, K. Torokhtii, N. Pompeo
We measure the flux-flow resistivity in FeSe$ _x$ Te$ _{1-x}$ epitaxial films using a microwave, dual-frequency technique. The flux-flow resistivity allows to open a window on the microscopic electronic state of quasiparticles. We obtain that the field-dependence of flux-flow is typical for multiband superconductors. Once this is assessed, we are able to extract the temperature dependence of the orbital upper critical field and of the normalised vortex core quasiparticle scattering time. Our data suggest that our epitaxial FeSe$ _x$ Te$ _{1-x}$ films are in the moderately clean regime.
Superconductivity (cond-mat.supr-con)
9 pages, 9 figures
Downfolding a quantum many-body system: the quasi-1D Fermi polaron
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-08 20:00 EDT
Lovro Anto Barišić (LPENS), Giuliano Orso (MPQ (UMR_7162)), Frédéric Chevy (LPENS, IUF), Kris Van Houcke (LPENS)
We investigate the properties of an impurity immersed in an ensemble of spin-polarized fermions confined in a tight quantum wire. We use a non-perturbative variational approach that accounts for virtual transverse excitations and regularizes the zero-range interaction. We compute the polaron’s energy, effective mass, and spectral weight, and benchmark our results against the exactly solvable Yang-Gaudin model of a purely 1D system. While the two models agree in the weakly interacting regime, we find significant deviations in the strongly attractive limit, including a divergence of the effective mass and evidence for a polaron-to-molecule transition inherited from the underlying 3D physics, which is absent in the purely 1D description. Our work quantifies the accuracy of quasi-1D systems as analog quantum simulators and highlights the emergence of beyond-1D physics even in nominally 1D settings.
Quantum Gases (cond-mat.quant-gas)
Stochastic processes with multiple temporal scales: timescale separation and information
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-08 20:00 EDT
Giorgio Nicoletti, Daniel M. Busiello
Complex systems are often characterized by the interplay of multiple interconnected dynamical processes operating across a range of temporal scales. This phenomenon is widespread in both biological and artificial scenarios, making it crucial to understand how such multiscale dynamics influence the overall functioning and behavior of these systems. Here, we present a general timescale separation approach that is valid for any set of stochastic differential equations coupled across multiple timescales. We show two alternative derivations, one based on an iterative procedure, and the other grounded on an a priori expansion in relevant small parameters associated with faster timescales. We provide an explicit expression for the conditional structure of the joint probability distribution of the whole set of processes that is solely determined by the multiscale interactions. This result has important consequences in determining how information is generated in the system and how it propagates across different timescales. To demonstrate that our findings are valid independently of the specific dynamical model, we test them against four different (linear and non-linear) dynamics. Then, we focus on the scenario in which two degrees of freedom are reciprocally coupled across their timescales. In this case, we show that the statistics of the fastest dynamics is captured by an effective self-interaction term in the slowest one, creating a regulatory loop. Finally, a connection with analogous previous results obtained for discrete-state systems with higher-order interactions is drawn, elucidating similarities and differences in the physical interpretation of the system. The presented framework might open the avenue for a clearer understanding of the interplay between the underlying multiscale structure and emergent functional behavior of biological and artificial systems.
Statistical Mechanics (cond-mat.stat-mech)
Note on searching for critical lattice models as entropy critical points from strange correlator
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
An entropy function is proposed in [Phys. Rev. Lett. 131, 251602] as a way to detect criticality even when the system size is small. In this note we apply this strategy in the search for criticality of lattice transfer matrices constructed based on the topological holographic principle. We find that the combination of strategy is indeed a cost-effective and efficient way of identifying critical boundary conditions, estimating central charges and moreover, plotting entire phase diagrams in a multi-dimensional phase space.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
10 pages, 7 figures. Comments are welcome
Internal Stresses as Origin of the Anomalous Low-Temperature Specific Heat in Glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-08 20:00 EDT
Walter Schirmacher, Giancarlo Ruocco
We apply a recently developed theory of the nonphononic vibrational density of states (DOS) in glasses to investigate the impact of local frozen-in stresses on the low-temperature specific heat. Using a completely harmonic description we show that the hybridization of the local nonphononic vibrational excitations with the waves leads to a low-frequency DOS, in excess to the Debye one, which varies linearly with frequency up to a certain crossover frequency, and then becomes constant. The actual value of the crossover depends of the ratio between the local stresses and the shear modulus. This excess DOS leads to a low-temperature specific heat with an apparent temperature exponent, which is between one and two, as observed experimentally. We discuss, how these findings may be utilized for the characterisation of glassy materials. We further compare our findings, which only rely on harmonic interactions, with the predictions of other theories, which invoke anharmonic interactions and tunneling for explaining the low-temperature behavior of the specific heat.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
8 pages, 1 figure
Further testing the validity of generalized heterogeneous-elasticity theory for low-frequency excitations in structural glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-08 20:00 EDT
Walter Schirmacher, Matteo Paoluzzi, Felix Cosmin Mocanu, Dmytro Khomenko, Grzegorz Szamel, Francesco Zamponi, Giancarlo Ruocco
In a recent paper E. Lerner and E. Bouchbinder,
Phys. Rev. E {\bf 111}, L013402 (2025) raised concerns regarding the validity of the theory and the interpretation of the data, presented in our previous study on non-phononic vibrational excitations in glasses,
W. Schirmacher {\it et al.}, Nature Comm. {\bf 15}, 3107 (2024).
In that work, we presented evidence suggesting that the commonly observed low-frequency regime of the non-phononic vibrational density of states (DoS) is, in fact, highly dependent on technical aspects of the molecular dynamics simulations employed to compute the DoS. Specifically, we showed that the $ \omega^4$ scaling results from the use of a tapering function applied to ensure continuity of the interaction potential at the cutoff distance. In this letter we report further evidence in favor of our previous findings, namely the non-universality of the $ \omega^4$ DoS scaling, and the existence of an important class of non-phononic excitations in glasses, which we call defect states, and are induced by frozen-in stresses. These modes can be classified as quasi-localized.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
4 pages, 2 figures
Optical spectra of small silver clusters with the Bethe-Salpeter formalism: a Reassessment
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
We study the optical absorption spectra of small Ag_n (n=2,4,6,8) clusters using the Bethe-Salpeter equation (BSE) formalism with a Hamiltonian built from GW quasiparticle energies. Calculations are based on an effective core potential including the 4sp shells in the valence. Non-self-consistent G0W0 calculations relying on input Kohn-Sham eigenstates generated with semilocal functionals lead to very poor BSE absorption spectra, confirming a previous observation. However, eigenvalue or quasiparticle self-consistent GW calculations dramatically improves the agreement with experiments and TD-DFT spectra obtained with range-separated hybrid functionals. The importance of the position of the 4d occupied band is emphasized.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Deep Learning-Assisted Weak Beam Identification in Dark-Field X-ray Microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
A. Benhadjira, C. Detlefs, S. Borgi, V. Favre-Nicolin, C. Yildirim
Dislocations control the mechanical behavior of crystalline materials, yet their quantitative characterization in bulk has remained elusive. Transmission Electron Microscopy provides atomic-scale resolution but is restricted to thin foils, limiting relevance to structural performance. Dark-field X-ray microscopy (DFXM) has recently opened access to three-dimensional, non-destructive imaging of dislocations in macroscopic crystals. A critical bottleneck, however, is the reliable identification of weak- versus strong-beam conditions. Weak-beam imaging enhances dislocation contrast, while strong-beam conditions are dominated by multiple scattering and obscure interpretation. Current practice depends on manual classification by specialists, which is subjective, slow, and incompatible with the scale of modern experiments. Here, we introduce a deep learning framework that automates this task using a lightweight convolutional neural network trained on small, hand-labeled datasets. By enabling robust, rapid, and scalable identification of imaging conditions, this approach transforms DFXM into a high-throughput tool, unlocking statistically significant studies of dislocation dynamics in bulk materials.
Materials Science (cond-mat.mtrl-sci)
Tuning Magneto-Optical Zero-Reflection via Dual-Channel Hybrid Magnonics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Andrew Christy, Yujie Zhu, Yi Li, Yuzan Xiong, Tao Qu, Frank Tsui, James F. Cahoon, Binbin Yang, Jia-Mian Hu, Wei Zhang
Multi-channel coupling in hybrid systems makes an attractive testbed not only because of the distinct advantages entailed in each constituent mode, but also the opportunity to leverage interference among the various excitation pathways. Here, via combined analytical calculation and experiment, we demonstrate that the phase of the magnetization precession at the interface of a coupled yttrium iron garnet(YIG)/permalloy(Py) bilayer is collectively controlled by the microwave photon field torque and the interlayer exchange torque, manifesting a coherent, dual-channel excitation scheme that effectively tunes the magneto-optic spectrum. The different torque contributions vary with frequency, external bias field, and types of interlayer coupling between YIG and Py, which further results in destructive or constructive interferences between the two excitation channels, and hence, selective suppression or amplification of the hybridized magnon modes.
Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Energy dependent Chemical Interface Damping induced by 1-Decanethiol Self-Assembled Monolayer on Au(111)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Maurice Pfeiffer, Gregor B. Vonbun-Feldbauer, Jacob B. Khurgin, Olga Matts, Ahmed Shqer, Nadiia Mameka, Manfred Eich, Alexander Petrov
The chemical interface damping (CID) effect increases the collision frequency of free electrons in metals by changes of the metal surface. We have now experimentally disentangled the two contributions to CID: induced roughness and direct charge transfer. The latter is an important area of research in photoelectrochemistry with potential applications in light-induced chemical reactions. We present a broadband investigation of the CID effect on Au(111) covered by a self-assembled monolayer of decanethiol. Spectroscopic ellipsometry measurements show a photon energy dependent increase of collision frequency. We observe a constant, photon energy independent contribution, which is attributed to induced roughness and a contribution that linearly increases with photon energy from about 1 eV upwards which we attribute to direct charge transfer. The onset of the charge transfer mechanism corresponds to occupied orbitals of thiols bound to the Au surface, as confirmed by density functional theory calculations.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Dynamical Learning in Deep Asymmetric Recurrent Neural Networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-08 20:00 EDT
Davide Badalotti, Carlo Baldassi, Marc Mézard, Mattia Scardecchia, Riccardo Zecchina
We show that asymmetric deep recurrent neural networks, enhanced with additional sparse excitatory couplings, give rise to an exponentially large, dense accessible manifold of internal representations which can be found by different algorithms, including simple iterative dynamics. Building on the geometrical properties of the stable configurations, we propose a distributed learning scheme in which input-output associations emerge naturally from the recurrent dynamics, without any need of gradient evaluation. A critical feature enabling the learning process is the stability of the configurations reached at convergence, even after removal of the supervisory output signal. Extensive simulations demonstrate that this approach performs competitively on standard AI benchmarks. The model can be generalized in multiple directions, both computational and biological, potentially contributing to narrowing the gap between AI and computational neuroscience.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG), Neurons and Cognition (q-bio.NC)
Few is different: deciphering many-body dynamics in mesoscopic quantum gases
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-08 20:00 EDT
Juergen Berges, Sandra Brandstetter, Jasmine Brewer, Georg Bruun, Tilman Enss, Stefan Floerchinger, Keisuke Fujii, Maciej Galka, Giuliano Giacalone, Qingze Guan, Carl Heintze, Lars H. Heyen, Ilya Selyuzhenkov, Selim Jochim, Jesper Levinsen, Philipp Lunt, Silvia Masciocchi, Aleksas Mazeliauskas, Nir Navon, Alice Ohlson, Meera Parish, Stephanie M. Reimann, Francesco Scazza, Thomas Schaefer, Derek Teaney, Joseph Thywissen, Raju Venugopalan, Yangqian Yan, Matteo Zaccanti, Torsten V. Zache
Emergent macroscopic descriptions of matter, such as hydrodynamics, are central to our description of complex physical systems across a wide spectrum of energy scales. The conventional understanding of these many-body phenomena has recently been shaken by a number of experimental findings. Collective behavior of matter has been observed in \emph{mesoscopic} systems, such as high-energy hadron-hadron collisions, or ultra-cold gases with only few strongly interacting fermions. In such systems, the separation of scales between macroscopic and microscopic dynamics (at the heart of any effective theory) is inapplicable. To address the conceptual challenges that arise from these observations and explore the universality of emergent descriptions of matter, the EMMI Rapid Reaction Task Force was assembled. This document summarizes the RRTF discussions on recent theoretical and experimental advances in this rapidly developing field. Leveraging technological breakthroughs in the control of quantum systems, we can now quantitatively explore what it means for a system to exhibit behavior beyond the sum of its individual parts. In particular, the report highlights how the (in)applicability of hydrodynamics and other effective theories can be probed across three principal frontiers: the size frontier, the equilibrium frontier, and the interaction frontier.
Quantum Gases (cond-mat.quant-gas), High Energy Physics - Phenomenology (hep-ph), Nuclear Theory (nucl-th), Quantum Physics (quant-ph)
65 pages, 12 figures, summary report of EMMI Rapid Reaction Task Force Workshop, March 18-21,2024, see this https URL
Exchange spin-wave propagation in Ga:YIG nanowaveguides
New Submission | Other Condensed Matter (cond-mat.other) | 2025-09-08 20:00 EDT
Andrey A. Voronov, Khrystyna O. Levchenko, Roman Verba, Kristýna Davídková, Carsten Dubs, Michal Urbánek, Qi Wang, Dieter Suess, Claas Abert, Andrii V. Chumak
Spin-wave-based computing has emerged as a promising approach to overcome the fundamental limitations of CMOS technologies. However, the increasing demand for device miniaturization down to a 100 nm scale presents significant challenges for long-distance spin-wave transport. Gallium-substituted yttrium iron garnet (Ga:YIG) offers a potential solution to these challenges due to its unique magnetic properties. The reduced saturation magnetization in Ga:YIG enables efficient excitation of exchange-dominated spin waves, which exhibit enhanced transport characteristics compared to dipolar-dominated modes in conventional materials. Here, we present the first comprehensive study combining experimental, analytical, and numerical investigations of spin-wave propagation in Ga:YIG waveguides down to 145 nm width and 73 nm thickness. Using micro-focused Brillouin light scattering spectroscopy, TetraX simulations, and analytical dispersion calculations, we demonstrate that Ga:YIG waveguides support spin waves with significantly higher group velocities up to 600 m/s. This value remains constant for structures with different widths, leading to longer spin-wave propagation lengths in nanowaveguides compared to non-substituted YIG. These results reveal that gallium substitution provides access to faster and longer-lived spin waves, opening new possibilities for implementing this material in nanoscale magnonic devices.
Other Condensed Matter (cond-mat.other)
Active thermodynamics of inertial chiral active gases: equation of state and edge currents
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-08 20:00 EDT
Lorenzo Caprini, Umberto Marini Bettolo Marconi, Benno Liebchen, Hartmut Löwen
One of the most fundamental quests in the physics of active matter concerns the existence of a comprehensive theory for its macroscopic properties, i.e. an ``active thermodynamics’’. Here, we derive and experimentally verify key elements of the active thermodynamics of ideal chiral active gases, unveiling edge currents and odd diffusivity as their peculiar features. Our main results are the derivation of an equation of state relating density and pressure via a chirality-dependent effective temperature, the derivation of Fick’s law including the full diffusion matrix predicting odd diffusion, and the exact prediction of edge currents at container walls that nonmonotonically depend on chirality.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Supersolidity induced flux magnetism with magnetic atoms in an anti-magic wavelength optical lattice
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-08 20:00 EDT
Michele Miotto, Pietro Lombardi, Giovanni Ferioli, Joana Fraxanet, Maciej Lewenstein, Luca Tanzi, Luca Barbiero
Supersolidity and magnetism are fundamental phenomena characterizing strongly correlated states of matter. Here, we unveil a mechanism that establishes a direct connection between these quantum regimes and can be experimentally accessed in ultracold atomic systems. Specifically, we exploit the distinctive properties of ultracold magnetic lanthanide atoms trapped in a one dimensional anti-magic wavelength optical lattice. This allows us to design a realistic implementation of a triangular Bose-Hubbard ladder featuring two essential ingredients: strong long-range interactions and tunable gauge fields. Thanks to these unconventional properties, our numerical analysis highlights that, among the others, a robust lattice supersolid regime with finite fluxes in each triangular plaquette occurs. Remarkably, we show that the specific density distribution of the supersolid phase leads to the magnetic ordering of fluxes, which can form ferrimagnetic and ferromagnetic structures. Our results thus discover a fascinating quantum mechanical effect that bridges supersolidity and magnetism.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
5 pages, 3 figures, and Supplemental Material
Fast optical data transfer into a Josephson junction array
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-08 20:00 EDT
K. Kohopää, J. Nissilä, E. Mykkänen, P. Selvasundaram, T. Fordell, K. Langi, E. T. Mannila, S. Kafanov, S. Ahopelto, H. Systä, M. Ribeiro, P. Sethi, M. Kiviranta, R. Loreto, J.-W. Lee, T. Rantanen, V. Vesterinen, O. Kieler, M. Bieler, J. Govenius, J. Senior, A. Kemppinen
We employ externally shunted Nb-AlO$ _x$ -Nb Josephson junctions for demonstrating a circuit that is suitable for an optically driven Josephson Arbitrary Waveform Synthesizer (JAWS). This technology enables overdamped junctions with characteristic frequencies above 100 GHz and critical currents of the order of 100 $ \mu$ A, which is promising, e.g., for low-dissipation optical control of quantum circuits such as superconducting quantum bits. Here we utilize a double-pulse technique to experimentally determine the maximum rate at which optical pulse data can be reliably delivered to the superconducting circuit. We demonstrate the feasibility of data transfer up to 60 Gbit/s, which is about factor 4 higher than for typical JAWS.
Superconductivity (cond-mat.supr-con)
Revisiting the Poor Man’s Majoranas: The Spin-Exchange Induced Spillover Effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-08 20:00 EDT
J.E. Sanches, T.M. Sobreira, L.S. Ricco, M.S. Figueira, A.C. Seridonio
We give a review on Poor Man’s Majorana (PMM) modes, which are theoretically established in the minimal Kitaev chain implementation consisting of two grounded, spinless quantum dots (QDs) operating at the sweet spot condition, where electron cotunneling and crossed Andreev reflection amplitudes achieve precise balance. Particularly, we systematically review, within the Green’s functions theoretical framework, the PMM hybridization dynamics under spin-exchange perturbations proposed by some of us in J. Phys.: Condens. Matter 37, 205601 (2025), which demonstrates a characteristic spatial delocalization when subjected to an exchange coupling $ J$ mediated by a quantum spin $ S$ . This spin-exchange induced PMM spillover effect provides a spectroscopic protocol for determining the quantum statistics of $ S$ through the emergent multi-level structure in the proximal QD’s density of states. Our principal theoretical result establishes that the exchange interaction generates $ 2S+2$ ($ 2S+1$ ) satellite states symmetrically distributed about the zero-bias anomaly, serving as a definitive signature of bosonic (fermionic) spin statistics. As novelty, we demonstrate that multi-terminal environmental coupling induces significant suppression of the spin-exchange spillover mechanism. Under constrained variations of $ J$ , this effectively localizes the perturbed PMM within its host QD, preventing spatial hybridization with adjacent site. The absence of topological protection in this minimal Kitaev realization is strategically leveraged to: (i) Develop a novel spectroscopic technique for quantum spin characterization through PMM hybridization signatures; (ii) Propose an engineered protection scheme for PMM qubits against exchange fluctuations in multi-terminal architectures, enabling moderately robust quantum computation protocols.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Efficient iPEPS Simulation on the Honeycomb Lattice via QR-based CTMRG
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
We develop a QR-based corner transfer matrix renormalization group (CTMRG) framework for contracting infinite projected entangled-pair states (iPEPS) on honeycomb lattices. Our method explicitly uses the lattice’s native C3v symmetry at each site, generalizing QR-based acceleration (previously limited to square lattices) to enable efficient and stable contractions. This approach achieves order-of-magnitude speedups over conventional singular value decomposition (SVD)-based CTMRG while maintaining high numerical precision. Comprehensive benchmark calculations for the spin-1/2 Heisenberg and Kitaev models demonstrate higher computational efficiency without sacrificing accuracy. We further employ our method to study the Kitaev-Heisenberg model, where we provide numerical evidence for the universal 1/r^4 decay of the dimer-dimer correlation function within the quantum spin liquid (QSL) phase. Our work establishes a framework for extending QR-based CTMRG to other lattice geometries, opening new avenues for studying exotic quantum phases with tensor networks.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
13 pages, 9 figures
Elasticity and plasticity of epithelial gap closure
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-08 20:00 EDT
Maryam Setoudeh, Pierre A. Haas
Epiboly, during which a tissue closes around the surface of the egg, pervades animal development. This epithelial gap closure involves cell intercalations at the edge of the gap. Here, inspired by serosa closure in the beetle Tribolium, we study the interplay between these plastic cell rearrangements and the elasticity of the tissue in a minimal continuum model of the closure of a circular gap bounded by a contractile actomyosin cable. We discover two different closure mechanisms at the tissue scale depending on the energy barrier $ E_\text{b}$ to and the energy $ \Delta E$ released by intercalation: If $ E_\text{b}\gg\Delta E$ , cells intercalate into the gap to close it. For a fluidised tissue in which $ E_\text{b}\ll\Delta E$ , however, cells deintercalate from the boundary into the bulk of the tissue, and we reveal an emergent mechanical role of inhomogeneities of the actomyosin cable. Our work thus explains the mechanical role of tissue fluidisation in Tribolium serosa closure and processes of epiboly and wound healing more generally.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Tissues and Organs (q-bio.TO)
6 pages, 5 figures; Supplemental Material: 8 pages, 2 figures
Universal Boundary-Modes Localization from Quantum Metric Length
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-08 20:00 EDT
Xing-Lei Ma, Jin-Xin Hu, K. T. Law
The presence of localized boundary modes is an unambiguous hallmark of topological quantum matter. While these modes are typically protected by topological invariants such as the Chern number, here we demonstrate that the {\it quantum metric length} (QML), a quantity inherent in multi-band topological systems, governs the spatial extent of flat-band topological boundary modes. We introduce a framework for constructing topological flat bands from degenerate manifolds with large quantum metric and find that the boundary modes exhibit dual phases of spatial behaviors: a conventional oscillatory decay arising from bare band dispersion, followed by another exponential decay controlled by quantum geometry. Crucially, the QML, derived from the quantum metric of the degenerate manifolds, sets a lower bound on the spatial spread of boundary states in the flat-band limit. Applying our framework to concrete models, we validate the universal role of the QML in shaping the long-range behavior of topological boundary modes. Furthermore, by tuning the QML, we unveil extraordinary non-local transport phenomena, including QML-shaped quantum Hall plateaus and anomalous Fraunhofer patterns. Our theoretical framework paves the way for engineering boundary-modes localization in topological flat-band systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Gas Sensing Properties of Novel Indium Oxide Monolayer: A First-Principles Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Afreen Anamul Haque, Suraj G. Dhongade, Aniket Singha
We present a comprehensive first-principles investigation into the gas sensing capabilities of a novel two-dimensional Indium Oxide (In2O3) monolayer, using density functional theory (DFT) calculations. Targeting both resistive-type and work function based detection mechanisms, we evaluate interactions with ten hazardous gases (NH3, NO, NO2, SO2, CS2, H2S, HCN, CCl2O, CH2O, CO) as well as ambient molecules (O2, CO2, H2O). The monolayer shows pronounced sensitivity towards NO and H2S, and work function modulation enables detection of NH3 and HCN. Mechanical strain further broadens detection capability, enhancing adsorption and selectivity. These results establish 2D In2O3 as a tunable platform for next-generation miniaturized gas sensors for environmental monitoring and safety applications.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
27 Pages, 6 figures
Hydrogen absorption in intermetallic compounds from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Olivier Nadeau, Romuald Béjaud, Lucas Baguet, Grégory Geneste, François Bottin, Gabriel Antonius
Intermetallic compounds such as {A$ _{2}$ B$ _{7}$ } alloys are promising candidates for mobile hydrogen storage applications due to their high and reversible hydrogen absorption capacity. We compute the absorption isotherm of {Nd$ _{3}$ MgNi$ _{14}$ } from first-principles using a multiscale modeling approach. Absorption sites are identified through a systematic geometrical analysis, and are characterized with Density Functional Theory (DFT) calculations. The absorption site properties are used in room-temperature Grand Canonical Monte Carlo simulations to predict hydrogen uptake as a function of pressure, leading to a full absorption isotherm in good agreement with experimental data. We show that both hybrid exchange-correlation functionals and zero-point energy corrections are necessary to obtain accurate absorption properties. The analysis of the fully hydrogenated structure with DFT shows considerable volume expansion, which stabilizes the structure at large hydrogen content.
Materials Science (cond-mat.mtrl-sci)
Continuum Landau surface states in a non-Hermitian Weyl semimetal
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-08 20:00 EDT
Shuxin Lin, Rimi Banerjee, Zheyu Cheng, Kohei Kawabata, Baile Zhang, Y. D. Chong
The surface states of topological phases, which owe their existence to bulk topological band invariants, possess many features of deep physical significance. In some instances, they can be linked to a quantum anomaly: the violation of a classical symmetry by a field theory through the emergence of a non-conserved current. This phenomenon was recently generalized to the non-Hermitian (NH) regime, in the form of an NH chiral anomaly occurring in the surfaces states of an NH Weyl phase. Here, we show that the anomalous NH current is mediated by continnum Landau modes (CLMs) an exotic class of NH eigenstates exhibiting both spatial localization and a continuous spectrum, contrary to the usual distinction between bound and free states. The conditions for which CLMs are normalized, and their scaling of localization length with magnetic field strength, are found to match the requirements of the NH anomaly equation. We also discuss the conditions under which these surface states can be probed experimentally, such as on metamaterial platforms. For instance, under open boundary conditions, the surface states are a mix of CLMs and skin modes induced by the NH skin effect, but the NH anomaly can be observed through transmission measurements under different magnetic fields.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
16 pages, 7 figures
Reply to the Comment by Tikhonov and Khrapai on “Long-range crossed Andreev reflection in a topological insulator nanowire proximitized by a superconductor”
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-08 20:00 EDT
Junya Feng, Henry F. Legg, Mahasweta Bagchi, Daniel Loss, Jelena Klinovaja, Yoichi Ando
The comment (arXiv:2505.23490) fails to identify any scientific errors and its central arguments actually support the main conclusions of our publication [Nat. Phys. 21, 708 (2025)]. Firstly, the whole argument of the comment to try to explain our data explicitly relies on the existence of a large crossed Andreev reflection (CAR) effect. The presence of a sizable CAR transmission probability over a surprisingly long distance is the first conclusion of our publication. Secondly, the comment discusses the complex interplay of CAR and elastic co-tunneling, especially in the presence of local effects. This complex interplay is precisely the second conclusion of our publication. In essence, the comment amounts to merely pointing out that there is a broader sense in the notion of “dominant CAR” when nonlinear effects become relevant.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Reply to arXiv:2505.23490
Cheaper access to universal fluctuations in integrable spin chains from boundary effects
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-08 20:00 EDT
Observing super-diffusive fluctuations from Kardar-Parisi-Zhang (KPZ) universality in isotropic integrable spin chains is usually challenging as it requires a fairly large number of spins in interaction. We demonstrate in this paper, in the context of classical spins, that accounting for boundary effects lowers the bar, down to a few dozen spins in some cases. Additionally, boundaries control the relaxation to stationarity, which leads to many new universal scaling functions to explore, both in periodic spin chains and for open chains with magnetization imposed by reservoirs at the ends.
Statistical Mechanics (cond-mat.stat-mech)
8+12 pages ; 3 ancillary csv files
Constraint effective action and critical correlation functions at fixed magnetization
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-08 20:00 EDT
Félix Rose, Adam Rançon, Ivan Balog
We present an extension of the functional renormalization group (FRG) framework developed to compute critical probability distributions of the order parameter to momentum-dependent observables. Focusing on the constraint effective action at fixed magnetization for the Ising universality class, we derive its exact flow equations and solve them at the second-order of the derivative expansion (DE2). We solve these flow equations numerically for two- and three-dimensional systems, extract universal rate functions and momentum-dependent correlation functions, and benchmark them against Monte Carlo simulations. In three dimensions, we recover the rate function and accurately reproduce the first few Fourier modes of the constrained correlation function, and demonstrate the convergence of the method. In two dimensions, the lowest order approximations such as local potential approximation (LPA) fail, and it is required to consider at least the DE2 to describe the critical point. Our results are in qualitative agreement with the numerics. We confirm the robustness of the FRG approach for calculating both zero- and finite-momentum critical observables at fixed magnetization.
Statistical Mechanics (cond-mat.stat-mech)
17 pages, 7 figures, 1 table
Orbital Ordering in the Charge Density Wave Phases of BaNi$2$(As${1-x}$P$_x$)$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-08 20:00 EDT
Tom Lacmann, Robert Eder, Igor Vinograd, Michael Merz, Mehdi Frachet, Philippa Helen McGuinness, Kurt Kummer, Enrico Schierle, Amir-Abbas Haghighirad, Sofia-Michaela Souliou, Matthieu Le Tacon
We use resonant X-ray scattering at the nickel L$ _{2,3}$ edges to investigate the interplay between orbital degrees of freedom and charge density waves (CDW) in the superconductor BaNi$ _2$ (As$ _{1-x}$ P$ _x$ )$ _2$ . Both the incommensurate and commensurate CDWs in this system exhibit strong resonant enhancement with distinct energy and polarization dependencies, indicative of orbital ordering. Azimuthal-angle-dependent measurements reveal a lowering of the local Ni site symmetry, consistent with monoclinic or lower point group symmetry. The scattering signatures of both CDWs are dominated by contributions from Ni d$ _{xz,yz}$ orbitals, with similar orbital character despite their distinct wave vectors. These findings point to a shared orbital-driven formation mechanism and provide new insight into the symmetry breaking and orbital/nematic fluctuations in the high-temperature regime of the superconductor BaNi$ _2$ (As$ _{1-x}$ P$ _x$ )$ _2$ .
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 3 figures, 15 pages SM, 8 SM figures
Correlation-driven 3d Heavy Fermion behavior in LiV2O4
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
Min-Yi-Nan Lei, Z. H. Chen, H. T. Wang, Y. Fan, N. Guo, T. X. Jiang, Yanwei Cao, T. Zhang, Rui Peng, Haichao Xu
LiV2O4 is a spinel-structured compound that stands out as the first known 3d-electron system exhibiting typical heavy fermion behavior. A central question is how such strong mass renormalization emerges in the absence of f-electrons. In this work, we investigate the three-dimensional electronic structure of LiV2O4 thin films using angle-resolved photoemission spectroscopy (ARPES). We identify that an electron-like flat band is derived from a1g orbitals, along with a highly dispersive e’g band strongly coupled with phonons. The overall agreement with dynamical mean-field theory (DMFT) calculations highlights the essential role of inter-orbital Hund’s coupling in reducing the a1g bandwidth to 25 meV, approaching a Mott state. Notably, we find that heavy-fermion behavior arises from additional renormalization at the a1g band near the Fermi level, likely driven by many-body interactions at energy scales down to a few meV and potentially linked to geometric frustration inherent to the spinel lattice. These results provide crucial insights into the origin of the heavy fermion behavior in 3d-electron systems.
Strongly Correlated Electrons (cond-mat.str-el)
Spin dynamics in natural multiferroic pyroxene NaFeSi$_2$O$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-08 20:00 EDT
Oleksandr Prokhnenko (1), Stanislav E. Nikitin (2), Koji Kaneko (3 and 4), Chihiro Tabata (3 and 4), Yusuke Hirose (3 and 4), Yoshifumi Tokiwa (4), Yoshinori Haga (4), Masaki Fujita (5), Hiroyuki Nojiri (5), Lawrence M. Anovitz (6), Andrey Podlesnyak (7) ((1) Helmholtz-Zentrum Berlin fűr Materialien und Energie, Berlin, Germany, (2) PSI Center for Neutron and Muon Sciences, Paul Scherrer Institut, Switzerland, (3) Materials Sciences Research Center, Japan Atomic Energy Agency, Tokai, Japan, (4) Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Japan, (5) Institute for Materials Research, Tohoku University, Sendai, Japan, (6) Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA, (7) Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA)
Spin dynamics in the natural mineral aegirine, NaFeSi$ _2$ O$ 6$ , a member of the pyroxene family, was studied by elastic and inelastic neutron scattering. Magnetization and specific heat measurements as well as single-crystal neutron diffraction maps, taken in the temperature range 2 - 20 K, confirm two successive magnetic transitions at 8.8 and 5.8 K, consistent with previous studies. The observed spin-wave excitations emerge from the incommensurate magnetic Bragg peaks corresponding to the propagation vector $ k{\rm ICM} = (0, 0.77, 0)$ , and extend up to energies of about 1.5 meV. In the low-temperature helical phase, the spin dynamics of the Fe$ ^{3+}$ ions is well described by a simple linear spin-wave model. The observed excitations can be modeled using a spin Hamiltonian that includes three primary exchange interactions - intrachain coupling $ J=0.142(2)$ meV, interchain couplings $ J_1=0.083(1)$ meV and $ J_2=0.186(1)$ meV - and an easy-plane anisotropy $ D=0.020(6)$ meV. Our results show that no single exchange interaction dominates the spin dynamics. The similar strengths of the intrachain and interchain couplings point to the fact that the magnetic interactions in aegirine are three-dimensional rather than confined along one direction. As a result, the system cannot be considered quasi-one-dimensional, as previously suggested, and calls for further investigations.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 5 figures
Phys. Rev. B 112 (2025) 094402
Nonreciprocal random networks and their percolation properties
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-08 20:00 EDT
We study the effects of nonreciprocity and network structure on percolation. To this end, we investigate nonreciprocal random networks - directed networks for which the probability of a link occurring from node i to node j differs from the probability of the reverse link occurring from node j to node i. We analytically determine the degree and percolation properties of such networks with exactly two types of link probability, demonstrating that whether the networks are structured such that the nodes are not statistically indistinguishable has profound effects on these measures, both quantitively and in how such networks need to be approached. In particular, we develop a technique for solving the percolation problem which can be applied to both structured and unstructured networks. The method entails writing self-consistent integral and differential equations for the probability that each node will belong to the network’s giant component. Exact solutions to these equations are obtained and simulations which confirm our analytic predictions are presented.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Physics and Society (physics.soc-ph)
20 pages, 10 figures
Vanadium-Engineered Co2NiSe4 Nanomaterial: Coupled Thermoelectric, Piezoelectric, and Electronic Optimization via DFT+U for Advanced Energy Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Ayesha Riaz, Sikander Azam, Qaiser Rafiq, Amin Ur Rahman, Qazi Muhammad Ahkam, Rafaqat Hussain, Rajwali Khan
To realize the creation of advanced multifunctional materials in energy storage and conversion technologies, the present research evaluates the structural, electronic, magnetic, thermodynamic, mechanical, thermoelectric, piezoelectric and optical properties of pristine and vanadium-doped Co2NiSe4 by first-principles density functional theory (DFT + U ). It addresses the use of vanadium substitution to tailor the material, its performance and the inclusion of diverse fields by changing its electronic structure and its bonding properties. It can be seen in the results that V doping improves electrical conductivity and magnetic ordering because of a higher density of states and a stronger spin polarization at the Fermi level. Thermodynamic calculations show enhanced entropy stabilization at high temperatures and, mechanical analysis suggests an enhanced elastic moduli that proves the enhanced structural integrity without affecting ductility. The thermoelectric properties have been greatly improved realize an optimal ZT of ~1.1 at 900 K with 5 at.% V doping owing to an ideal combination of Seebeck coefficient, electrical conductivity, and inhibited thermal conductivity. Also, optical analysis reveals that expanded absorption spectra, increased dielectric response, adjustable reflectivity and energy loss spectra, optical properties can be used in photonic, and other optoelectronic devices. Better piezoelectric coefficients due to its effectiveness when doped also appeal to the usefulness of its application in nanoscale electromechanical systems. The combination of these results makes V-doped Co2NiSe4, a versatile material platform of next-generation energy storage, thermoelectric generation, and novel multifunctional sensors.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Local Mechanical Response of Lipid Membranes to Tilt Deformation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-08 20:00 EDT
Using molecular dynamics, this study investigates the local elastic properties of transverse shear deformation of lipid membranes. The analysis demonstrates that transverse shear deformation induces anisotropy in the local stress profile of the lipid bilayer, a phenomenon attributed to the Poynting effect. By analyzing the relationship between transverse shear stress and the induced anisotropy, the local transverse shear modulus is determined. From the local transverse shear modulus, several integral elastic parameters can be derived, including the monolayer tilt modulus, tilt-curvature coupling modulus, and curvature-gradient modulus. The calculated tilt modulus values show good agreement with results from an independent analysis of lipid director fluctuations.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Illuminating Stability and Spectral Shifts: A DFT+U Study of Eu-Doped ZnWO$_4$ for Visible-Light Optoelectronics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-08 20:00 EDT
Muhammad Tayyab, Sikander Azam, Qaiser Rafiq, Vineet Tirth, Ali Algahtani, Amin Ur Rahman, Syed Sheraz Ahmad, M. Tahir Khan
Tungstate-based oxides have attracted significant attention owing to their excellent structural stability, chemical robustness, and versatile optical properties, making them suitable for next-generation optoelectronic and phosphor applications. Among these, ZnWO$ _4$ has emerged as a promising host matrix; however, the role of europium (Eu) substitution in modulating its optoelectronic behavior remains underexplored. In this work, we employ spin-polarized density functional theory (DFT) within the GGA+U framework to investigate the structural, electronic, and optical properties of pristine ZnWO$ _4$ and Eu-doped ZnWO4 systems. Phonon dispersion analysis confirms dynamical stability for both pristine and doped structures. Eu doping reduces the bandgap, introduces new localized states near the Fermi level, and significantly alters the density of states, thereby enhancing electronic transitions. The optical response reveals a broadened dielectric function, red-shifted absorption edge, and intensified extinction coefficient, consistent with the presence of Eu 4f states. Additionally, reflectivity and energy-loss spectra indicate improved photon-phonon coupling and optical tunability upon doping. These findings highlight that Eu incorporation not only stabilizes the ZnWO$ _4$ lattice but also tailors its optoelectronic features, positioning Eu-doped ZnWO4 as a potential candidate for white-light-emitting diodes (w-LEDs) and related optoelectronic technologies.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)