CMP Journal 2025-07-08
Statistics
Physical Review Letters: 10
Physical Review X: 2
arXiv: 170
Physical Review Letters
Matchgate Circuits Deeply Thermalize
Research article | Quantum computation | 2025-07-07 06:00 EDT
Mircea Bejan, Benjamin Béri, and Max McGinley
We study the ensemble of states generated by performing projective measurements on the output of a random matchgate (or free-fermionic) quantum circuit. We rigorously show that this ‘’projected ensemble’’ exhibits deep thermalization: for large system sizes, it converges toward a universal ensemble that is uniform over the manifold of Gaussian fermionic states. As well as proving momentwise convergence of these ensembles, we demonstrate that the full distribution of any physical observable in the projected ensemble is close to its universal form in Wasserstein-1 distance, which we argue is an appropriate and efficiently computable measure of convergence when studying deep thermalization. Using this metric, we also numerically find that local matchgate circuits deeply thermalize after a timescale $t\sim {L}^{2}$ set by the diffusive spreading of quantum information. Our work opens up new avenues to experimentally accessible protocols to probe the emergence of quantum statistical mechanics and benchmark quantum simulators.
Phys. Rev. Lett. 135, 020401 (2025)
Quantum computation, Quantum information theory, Quantum measurements, Quantum simulation, Quantum statistical mechanics
Measuring Decoherence Due to Quantum Vacuum Fluctuations
Research article | Open quantum systems & decoherence | 2025-07-07 06:00 EDT
Anirudh Gundhi and Hendrik Ulbricht
The interaction of a particle with vacuum fluctuations—which theoretically exist even in the complete absence of matter—can lead to observable irreversible decoherence if it were possible to switch on and off the particle charge suddenly. We compute the leading order decoherence effect for such a scenario and propose an experimental setup for its detection. Such a measurement might provide further insights into the nature of vacuum fluctuations and a novel precision test for the decoherence theory.
Phys. Rev. Lett. 135, 020402 (2025)
Open quantum systems & decoherence, Quantum-to-classical transition
Pseudoentanglement from Tensor Networks
Research article | Matrix product states | 2025-07-07 06:00 EDT
Zihan Cheng, Xiaozhou Feng, and Matteo Ippoliti
Pseudoentangled states are defined by their ability to hide their entanglement structure: they are indistinguishable from random states to any observer with polynomial resources, yet can have much less entanglement than random states. Existing constructions of pseudoentanglement based on phase and/or subset states are limited in the entanglement structures they can hide, e.g., the states may have low entanglement on a single cut, on all cuts at once, or on local cuts in one dimension. Here, we introduce new constructions of pseudoentangled states based on (pseudo)random tensor networks that afford much more flexibility in the achievable entanglement structures. We illustrate our construction with the simplest example of a matrix product state, realizable as a staircase circuit of pseudorandom unitary gates, which exhibits pseudo-area-law scaling of entanglement in one dimension. We then generalize our construction to arbitrary tensor network structures that admit an isometric realization. A notable application of this result is the construction of pseudoentangled ‘’holographic’’ states whose entanglement entropy obeys a Ryu-Takayanagi ‘’minimum-cut’’ formula, answering a question posed in Aaronson et al. [arXiv:2211.00747].
Phys. Rev. Lett. 135, 020403 (2025)
Matrix product states, Quantum entanglement, Tensor network renormalization, Random matrix theory, Tensor network methods
Composite Heavy Axionlike Dark Matter
Research article | Composite bosons | 2025-07-07 06:00 EDT
Pierluca Carenza, Roman Pasechnik, and Zhi-Wei Wang
We propose a novel class of dark matter (DM) candidates in the form of a heavy composite axionlike particle (ALP) with highly suppressed electromagnetic interactions populating vast yet unexplored domains in the ALP parameter space. This is achieved for the first time in the simplest dark confining gauge theory yielding a new composite glueball ALP (GALP) DM coupling-mass relation found in terms of two distinct fundamental scales—the large dark fermion mass scale and the dynamical scale of dark confinement. The presence of a heavy fermion portal between the visible (photons) and dark (GALPs) sectors ensures a strong radiative suppression of the GALP-photon coupling naturally without any fine-tuning. The observable features of heavy GALP DM in a minimal realization are controlled by only three physical parameters. Our work paves the road for a novel research field exploring the theory and phenomenology of composite ALPs in multimessenger astrophysics and cosmology.
Phys. Rev. Lett. 135, 021001 (2025)
Composite bosons, Dark matter, Particle dark matter, Axions
Firewalls from General Covariance
Research article | General relativity | 2025-07-07 06:00 EDT
Raphael Bousso
I define ‘’horizon normalcy’’ as the approximate validity of semiclassical gravity and effective field theory for the description of observers that approach or cross a black hole horizon. If black holes return information, then horizon normalcy must fail substantially, at least in some global states. It has been proposed that horizon normalcy persists, so long as the Hawking radiation remains in a computationally simple state. Here I argue that state-dependent horizon normalcy—independent of the underlying mechanism and independent of the class of radiation states asserted to guarantee normalcy—requires a breakdown of general covariance far from the black hole, or else horizon normalcy will depend on the infinite future of the exterior. This is because the radiation can be in different states at different events, all spacelike to the horizon crossing event whose normalcy is at stake. I discuss a related effect in AdS/CFT, and I argue that its resolution by timefolds is of no help here.
Phys. Rev. Lett. 135, 021501 (2025)
General relativity, Quantum gravity, Relativistic quantum information
Incorporating Physical Priors into Weakly Supervised Anomaly Detection
Research article | Phenomenology | 2025-07-07 06:00 EDT
Chi Lung Cheng, Gup Singh, and Benjamin Nachman
We propose a new machine-learning-based anomaly detection strategy for comparing data with a background-only reference (a form of weak supervision). The sensitivity of previous strategies degrades significantly when the signal is too rare or there are many unhelpful features. Our prior-assisted weak supervision (PAWS) method incorporates information from a class of signal models to significantly enhance the search sensitivity of weakly supervised approaches. As long as the true signal is in the prespecified class, PAWS matches the sensitivity of a dedicated, fully supervised method without specifying the exact parameters ahead of time. On the benchmark LHC Olympics anomaly detection dataset, our mix of semisupervised and weakly supervised learning is able to extend the sensitivity over previous methods by a factor of 10 in cross section. Furthermore, if we add irrelevant (noise) dimensions to the inputs, classical methods degrade by another factor of 10 in cross section while PAWS remains insensitive to noise. This new approach could be applied in a number of scenarios and pushes the frontier of sensitivity between completely model-agnostic approaches and fully model-specific searches.
Phys. Rev. Lett. 135, 021801 (2025)
Phenomenology, Signatures with new bosons, Artificial neural networks, Machine learning
Quark Matter at Four Loops: Hardships and How to Overcome Them
Research article | Finite temperature field theory | 2025-07-07 06:00 EDT
Aapeli Kärkkäinen, Pablo Navarrete, Mika Nurmela, Risto Paatelainen, Kaapo Seppänen, and Aleksi Vuorinen
A new theoretical framework simplifies the four-loop Feynman diagrams for dense QCD to few infrared-finite integrals, which brings the higher-order calculation of the pressure inside cold and dense quark matter within reach.
Phys. Rev. Lett. 135, 021901 (2025)
Finite temperature field theory, Perturbative QCD, Quantum chromodynamics, Quark matter, Neutron stars & pulsars
QCD Predictions for Physical Multimeson Scattering Amplitudes
Research article | Hadron-hadron interactions | 2025-07-07 06:00 EDT
Sebastian M. Dawid, Zachary T. Draper, Andrew D. Hanlon, Ben Hörz, Colin Morningstar, Fernando Romero-López, Stephen R. Sharpe, and Sarah Skinner
We use lattice QCD calculations of the finite-volume spectra of systems of two and three mesons to determine, for the first time, three-particle scattering amplitudes with physical quark masses. Our results are for combinations of ${\pi }^{+}$ and ${K}^{+}$, at a lattice spacing $a=0.063\text{ }\text{ }\mathrm{fm}$, and in the isospin-symmetric limit. We also obtain accurate results for maximal-isospin two-meson amplitudes, with those for ${\pi }^{+}{K}^{+}$ and $2{K}^{+}$ being the first determinations at the physical point. Dense lattice spectra are obtained using the stochastic Laplacian-Heaviside method, and the analysis leading to scattering amplitudes is done using the relativistic finite-volume formalism. Results are compared to chiral perturbation theory and to phenomenological fits to experimental data, finding good agreement.
Phys. Rev. Lett. 135, 021903 (2025)
Hadron-hadron interactions, Lattice QCD, Scattering amplitudes
Quantum Stochastic Rectification in a Single Molecule
Research article | Adsorption | 2025-07-07 06:00 EDT
Jiang Yao, Siyu Chen, Wenlu Shi, and W. Ho
Monitoring the conformational switching of a single molecule using inelastic electron tunneling spectroscopy demonstrates quantum stochastic rectification.
Phys. Rev. Lett. 135, 026201 (2025)
Adsorption, Chemical Physics & Physical Chemistry, Surface & interfacial phenomena, Inelastic electron tunneling spectroscopy, Scanning tunneling microscopy
Observing the Mobile Surface Layer of Water During Vapor Deposition and Its Impact on Structure
Research article | Dielectric properties | 2025-07-07 06:00 EDT
Erik Thoms, Jan P. Gabriel, and Ranko Richert
Surface mobility can determine whether a deposited film of solid water will be in a porous or collapsed amorphous phase, or if it will form crystalline ice.
Phys. Rev. Lett. 135, 028001 (2025)
Dielectric properties, Glassy systems, Surfaces, Thin films, Water, Dielectric spectroscopy, Physical vapor deposition
Physical Review X
Multipolar Anisotropy in Anomalous Hall Effect from Spin-Group Symmetry Breaking
Research article | Anomalous Hall effect | 2025-07-07 06:00 EDT
Zheng Liu, Mengjie Wei, Wenzhi Peng, Dazhi Hou, Yang Gao, and Qian Niu
A new symmetry-breaking scenario provides a comprehensive description of magnetic behavior associated with the anomalous Hall effect.
Phys. Rev. X 15, 031006 (2025)
Anomalous Hall effect, Electronic structure, Ferromagnetism, Geometric & topological phases, Spin-orbit coupling
Regularizing 3D Conformal Field Theories via Anyons on the Fuzzy Sphere
Research article | Fractional quantum Hall effect | 2025-07-07 06:00 EDT
Cristian Voinea, Ruihua Fan, Nicolas Regnault, and Zlatko Papić
Simulations on a fuzzy sphere show that 3D Ising critical behavior persists even in fractional quantum Hall states, revealing a powerful method for studying conformal field theories amid topological order.
Phys. Rev. X 15, 031007 (2025)
Fractional quantum Hall effect, Phase transitions, Conformal field theory, Ising model, Noncommutative geometry, Symmetries in condensed matter
arXiv
A shear-induced limit on bacterial surface adhesion in fluid flow
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Edwina F. Yeo, Benjamin J. Walker, Philip Pearce, Mohit P. Dalwadi
Controlling bacterial surface adhesion and subsequent biofilm formation in fluid systems is crucial for the safety and efficacy of medical and industrial processes. Here, we theoretically examine the transport of bacteria close to surfaces, isolating how the key processes of bacterial motility and fluid flow interact and alter surface adhesion. We exploit the disparity between the fluid velocity and the swimming velocity of common motile bacteria and, using a hybrid asymptotic-computational approach, we systematically derive the coarse-grained bacterial diffusivity close to surfaces as a function of swimming speed, rotational diffusivity, and shape. We calculate an analytical upper bound for the bacterial adhesion rate by considering the scenario in which bacteria adhere irreversibly to the surface on first contact. Our theory predicts that maximal adhesion occurs at intermediate flow rates: at low flow rates, increasing flow increases surface adhesion, while at higher flow rates, adhesion is decreased by shear-induced cell reorientation.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Nonlinear ferroelectric characteristics of barium titanate nanocrystals determined via a polymer nanocomposite approach
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Qiong Li, Elshad Allahyarov, Tianxiong Ju, Zhiqun Lin, Lei Zhu
The growing demand for high energy storage materials has garnered substantial attention towards lead-free ferroelectric nanocrystals (NCs), such as BaTiO3 (BTO), for next-generation multilayer ceramic capacitors. Notably, it remains challenging to accurately measure the dielectric constant and polarization-electric field (P-E) hysteresis loop for BTO NCs. Herein, we report on nonlinear ferroelectric characteristics of BTO NCs via a polymer nanocomposite approach. Specifically, poly(vinyl pyrrolidone)(PVP)/BTO nanocomposite films of 3-10 {\mu}m thickness, containing 380 nm tetragonal-phased and 60 nm cubic-phased BTO NCs with uniform particle dispersion, were prepared. Theoretical deconvolution of the broad experimental P-E loops of the PVP/BTO NC composite films revealed three contributions, that is, the linear deformational polarization of the nanocomposites, the polarization of BTO NCs (Pp ), and the polarization from strong particle-particle interactions. Using different mixing rules and nonlinear dielectric analysis, the overall dielectric constants of BTO NCs were obtained, from which the internal field in the BTO NCs (Ep ) was estimated. Consequently, the Pp-Ep hysteresis loops were obtained for the BTO380 and BTO60 NCs. Interestingly, BTO380 exhibited square-shaped ferroelectric loops, whereas BTO60 displayed slim paraelectric loops. This work presents a robust and versatile route to extract the Pp-Ep loops of ferroelectric NCs from polymer/ceramic nanocomposites.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
16 pages, 14 figures
Nanoscale, 2024, 16, 3606-3621
Link between Continuous and Discrete Descriptions of Noise in Nonlinear Resistive Electrical Components
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Lucas Désoppi, Bertrand Reulet
We consider the modeling of a nonlinear, classical, resistive electrical component using two models: i) a continuous description based on a stochastic differential equation with a white thermal Gaussian noise; ii) a discrete, shot noise model based on a Markovian master equation. We show that thermodynamics imposes in i) the use of the Hänggi-Klimontovich (H-K) prescription when the noise depends on bias voltage, and implies a generalized Johnson-Nyquist relation for the noise where the conductance is replaced by the ratio mean current over voltage. In ii) we show that the discrete description compatible with thermodynamics leads to the continuous one of i) with again the H-K prescription. Here the generalized Johnson-Nyquist relation for noise is recovered only at low voltage, when the continuous description is valid.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages. Submitted to Fluctuation and Noise Letters
Quasiconservation Laws and Suppressed Transport in Weakly Interacting Localized Models
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Jessica Kaijia Jiang, Federica Maria Surace, Olexei I. Motrunich
The stability of localization in the presence of interactions remains an open problem, with finite-size effects posing significant challenges to numerical studies. In this work, we investigate the perturbative stability of noninteracting localization under weak interactions, which allows us to analyze much larger system sizes. Focusing on disordered Anderson and quasiperiodic Aubry-André models in one dimension, and using the adiabatic gauge potential (AGP) at first order in perturbation theory, we compute first-order corrections to noninteracting local integrals of motion (LIOMs). We find that for at least an $ O(1)$ fraction of the LIOMs, the corrections are well-controlled and converge at large system sizes, while others suffer from resonances. Additionally, we introduce and study the charge-transport capacity of this weakly interacting model. To first order, we find that the charge transport capacity remains bounded in the presence of interactions. Taken together, these results demonstrate that localization is perturbatively stable to weak interactions at first order, implying that, at the very least, localization persists for parametrically long times in the inverse interaction strength. We expect this perturbative stability to extend to all orders at sufficiently strong disorder, where the localization length is short, representing the true localized phase. Conversely, our findings suggest that the previously proposed interaction-induced avalanche instability, namely in the weakly localized regime of the Anderson and Aubry-André models, is a more subtle phenomenon arising only at higher orders in perturbation theory or through nonperturbative effects.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
34 pages, 23 figures
Dynamical correlation functions for the one-dimensional Bose-Hubbard insulator
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Kevin zu Münster, Florian Gebhard, Satoshi Ejima, Holger Fehske
We calculate the dynamical current and kinetic-energy correlation functions for the first Mott lobe of the one-dimensional Bose-Hubbard model. We employ the strong-coupling expansion up to sixth order in $ x=t/U$ , and the dynamical density-matrix renormalization group method on rings with 64 sites. The correlation functions are finite above the single-particle gap with a square-root onset, as is also found from field theory close to the Mott transition. The correlation functions display a featureless superposition of the primary and tertiary Hubbard bands. We find very good agreement between all methods in the interaction/frequency regimes where they are applicable.
Quantum Gases (cond-mat.quant-gas)
final version, 8 pages, 4 figures
Phys. Rev. A 89, 063623 (2014)
Spin-Glass Phases and Multichaos in the Ashkin-Teller Model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-08 20:00 EDT
The global phase diagram of the Ashkin-Teller spin glass is calculated in d = 3 spatial dimensions by renormalization-group theory. Depending on the value of the positive or negative four-spin interaction, qualitatively different topologies are found for the spin-glass phase diagram in the usual variables of temperature and fraction of antiferromagnetic nearest-neighbor interactions. Two different spin-glass phases occur. Both spin-glass phases are chaotic. One spin-glass exhibits phase reentrance that is reverse from the reentrances seen in previous spin-glass phase diagrams. Seven different phases: Ferromagnetic and antiferromagnetic, entropic ferromagnetic and entropic antiferromagnetic, spin-glass and entropic spin-glass, and disordered phases occur. The entropic ferromagnetic phase unusually but understandably occurs at temperatures above one spin-glass phase. A random disorder line is identified and no phase transition occurs on this lie. Our calculation is exact on the d = 3 hierarchical lattice and Migdal-Kadanoff approximate on the cubic lattice.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
7 pages, 6 figures, 1 table. arXiv admin note: text overlap with arXiv:2502.12201
Electrostatics in semiconducting devices II : Solving the Helmholtz equation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Antonio Lacerda-Santos, Xavier Waintal
The convergence of iterative schemes to achieve self-consistency in mean field problems such as the Schrödinger-Poisson equation is notoriously capricious. It is particularly difficult in regimes where the non-linearities are strong such as when an electron gas in partially depleted or in presence of a large magnetic field. Here, we address this problem by mapping the self-consistent quantum-electrostatic problem onto a Non-Linear Helmoltz (NLH) equation at the cost of a small error. The NLH equation is a generalization of the Thomas-Fermi approximation. We show that one can build iterative schemes that are provably convergent by constructing a convex functional whose minimum is the seeked solution of the NLH problem. In a second step, the approximation is lifted and the exact solution of the initial problem found by iteratively updating the NLH problem until convergence. We show empirically that convergence is achieved in a handfull, typically one or two, iterations. Our set of algorithms provide a robust, precise and fast scheme for studying the effect of electrostatics in quantum nanoelectronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
21 pages, 9 figures
Quantics Tensor Train for solving Gross-Pitaevskii equation
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Aleix Bou-Comas, Marcin Płodzień, Luca Tagliacozzo, Juan José García-Ripoll
We present a quantum-inspired solver for the one-dimensional Gross-Pitaevskii equation in the Quantics Tensor-Train (QTT) representation. By evolving the system entirely within a low-rank tensor manifold, the method sidesteps the memory and runtime barriers that limit conventional finite-difference and spectral schemes. Two complementary algorithms are developed: an imaginary-time projector that drives the condensate toward its variational ground state and a rank-adapted fourth-order Runge-Kutta integrator for real-time dynamics. The framework captures a broad range of physical scenarios - including barrier-confined condensates, quasi-random potentials, long-range dipolar interactions, and multicomponent spinor dynamics - without leaving the compressed representation. Relative to standard discretizations, the QTT approach achieves an exponential reduction in computational resources while retaining quantitative accuracy, thereby extending the practicable regime of Gross-Pitaevskii simulations on classical hardware. These results position tensor networks as a practical bridge between high-performance classical computing and prospective quantum hardware for the numerical treatment of nonlinear Schrodinger-type partial differential equations.
Quantum Gases (cond-mat.quant-gas)
Mapping phase diagrams of quantum spin systems through semidefinite-programming relaxations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
David Jansen, Donato Farina, Luke Mortimer, Timothy Heightman, Andreas Leitherer, Pere Mujal, Jie Wang, Antonio Acín
Identifying quantum phase transitions poses a significant challenge in condensed matter physics, as this requires methods that both provide accurate results and scale well with system size. In this work, we demonstrate how relaxation methods can be used to generate the phase diagram for one- and two-dimensional quantum systems. To do so, we formulate a relaxed version of the ground-state problem as a semidefinite program, which we can solve efficiently. Then, by taking the resulting vector of operator monomials for different model parameters, we identify all first- and second-order transitions based on their cosine similarity. Furthermore, we show how spontaneous symmetry breaking is naturally captured by bounding the corresponding observable. Using these methods, we reproduce the phase transitions for the one-dimensional transverse field Ising model and the two-dimensional frustrated bilayer Heisenberg model. We also illustrate how the phase diagram of the latter changes when a next-nearest-neighbor interaction is introduced. Overall, our work demonstrates how relaxation methods provide a novel framework for studying and understanding quantum phase transitions.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 6 Figures
Quasiparticle energies and excitonic effects of α-RuCl3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
{\alpha}-phase Ruthenium (III) chloride ({\alpha}-RuCl3) has attracted significant attention because of its potential for realizing Kitaev quantum spin liquid. In this work, we employ first-principles many-body perturbation theory to study its many-electron interactions and excited-state properties. We find enhanced many-electron interactions that dominate quasiparticle energies and optical responses in {\alpha}-RuCl3. Our calculated quasiparticle band gap of bulk structure is about 1.75 eV that agrees well with recent scanning tunneling spectroscopy and angle-resolved photoemission spectroscopy measurements. Furthermore, our calculated first and second primary bright excitons are located at 1.23 eV and 1.98 eV, respectively. These excitons show good consistency with the main features observed in the optical absorption spectrum. We extend our investigation to monolayer {\alpha}-RuCl3, examining the zigzag antiferromagnetic (AFM) and ferromagnetic (FM) phases. In addition to significant excitonic effects, the optical spectrum of the zigzag AFM phase exhibits anisotropic behavior, while the FM phase demonstrates isotropic characteristics. The different optical response behaviors provide an efficient approach to identify the energy nearly degenerate magnetic states, which can both potentially exist in fabricated samples.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Five figures and one table
Domain Growth in Long-range Ising Models with Disorder
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Ramgopal Agrawal, Federico Corberi, Eugenio Lippiello, Sanjay Puri
Recent advances have highlighted the rich low-temperature kinetics of the long-range Ising model (LRIM). This study investigates domain growth in an LRIM with quenched disorder, following a deep low-temperature quench. Specifically, we consider an Ising model with interactions that decay as $ J(r) \sim r^{-(D+\sigma)}$ , where $ D$ is the spatial dimension and $ \sigma > 0$ is the power-law exponent. The quenched disorder is introduced via random pinning fields at each lattice site. For nearest-neighbor models, we expect that domain growth during activated dynamics is logarithmic in nature: $ R(t) \sim (\ln t)^{\alpha}$ , with growth exponent $ \alpha >0$ . Here, we examine how long-range interactions influence domain growth with disorder in dimensions $ D = 1$ and $ D = 2$ . In $ D = 1$ , logarithmic growth is found to persist for various $ \sigma > 0$ . However, in $ D = 2$ , the dynamics is more complex due to the non-trivial interplay between extended interactions, disorder, and thermal fluctuations.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
33 pages, 15 figures
Effective anisotropic interaction potentials for pairs of ultracold molecules shielded by a static electric field
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Bijit Mukherjee, Luis Santos, Jeremy M. Hutson
Quantum gases of ultracold polar molecules have novel properties because of the strong dipolar forces between molecules. Current experiments shield the molecules from destructive collisions by engineering long-range repulsive interactions using microwave or static electric fields. These shielding methods produce interaction potentials with large repulsive cores that are not well described with contact potentials. In this paper we explore the anisotropic interaction potentials that arise for pairs of polar molecules shielded with static electric fields. We derive computationally inexpensive approximations for the potentials that are suitable for use in calculations of many-body properties. The interaction potentials for molecules shielded with static fields are qualitatively different from those that arise from single-field microwave shielding and will produce quite different many-body physics.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
11 pages, 11 figures
Revealing electron-electron interactions in graphene at room temperature with the quantum twisting microscope
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
M. Lee, I. Das, J. Herzog-Arbeitman, J. Papp, J. Li, M. Daschner, Z. Zhou, M. Bhatt, M. Currle, J. Yu, Yi Jiang, M. Becherer, R. Mittermeier, P. Altpeter, C. Obermayer, H. Lorenz, G. Chavez, B. T. Le, J. Williams, K. Watanabe, T. Taniguchi, B. Andrei Bernevig, D. K. Efetov
The Quantum Twisting Microscope (QTM) is a groundbreaking instrument that enables energy- and momentum-resolved measurements of quantum phases via tunneling spectroscopy across twistable van der Waals heterostructures. In this work, we significantly enhance the QTMs resolution and extend its measurement capabilities to higher energies and twist angles by incorporating hexagonal boron nitride (hBN) as a tunneling dielectric. This advancement unveils previously inaccessible signatures of the dispersion in the tunneling between two monolayer graphene (MLG) sheets, features consistent with a logarithmic correction to the linear Dirac dispersion arising from electron-electron (e-e) interactions with a fine-structure constant of alpha = 0.32. Remarkably, we find that this effect, for the first time, can be resolved even at room temperature, where these corrections are extremely faint. Our results underscore the exceptional resolution of the QTM, which, through interferometric interlayer tunneling, can amplify even subtle modifications to the electronic band structure of two-dimensional materials. Our findings reveal that strong e-e interactions persist even in symmetric, nonordered graphene states and emphasize the QTMs unique ability to probe spectral functions and their excitations of strongly correlated ground states across a broad range of twisted and untwisted systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
High-throughput screening of charge-order-induced ferroelectrics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Jose Cuevas-Medina, Yubo Qi, Natasa Stojic, Sebastian E. Reyes-Lillo
Charge-order-induced ferroelectrics display important technological applications in spintronics devices due to the possibility of magnetoelectric coupling and fast electronic switching. However, the list of known charge-order-induced ferroelectrics remains limited, hindering the fundamental understanding of the phenomena and the optimization of materials for real applications. In this work, we develop a high-throughput workflow to screen for charge-order-induced ferroelectrics in The Materials Project database. We use the local symmetry and bond valence sum to determine 147 materials displaying a coexistence of charge order and ferroelectric polarization. Then, ab initio simulations are used to identify 21 charge-order-induced ferroelectric candidates in which the ferroelectric polarization originates from or is structurally coupled to the charge order. For the final 21 candidates, we use symmetry-adapted modes and first-principles calculations to determine the structural coupling term between charge order and polar distortions and compute electronic properties, respectively.
Materials Science (cond-mat.mtrl-sci)
13 pages, 8 figures
System-Bath Approach to Rotational Brownian Motion
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Ashot Matevosyan, Armen E. Allahverdyan
Rotational equilibrated systems are widespread, but relatively little attention has been devoted to studying them from the first principles of statistical mechanics. Here we bridge this gap, as we look at a Brownian particle coupled with a rotational thermal bath modeled via Caldeira-Leggett oscillators. We show that the Langevin equation that describes the dynamics of the Brownian particle contains (due to rotation) long-range correlated noise. In contrast to the usual situation of non-rotational equilibration, the rotational Gibbs distribution is recovered only for a weak coupling with the bath. However, the presence of a uniform magnetic field disrupts equilibrium, even under weak coupling conditions. In this context, we clarify the applicability of the Bohr-van Leeuwen theorem to classical systems in rotational equilibrium, as well as the concept of work done by a changing magnetic field. Additionally, we show that the Brownian particle under a rotationally symmetric potential reaches a stationary state that behaves as an effective equilibrium, characterized by a free energy. As a result, no work can be extracted via cyclic processes that respect the rotation symmetry. However, if the external potential exhibits asymmetry, then work extraction via slow cyclic processes is possible. This is illustrated by a general scenario, involving a slow rotation of a non-rotation-symmetric potential.
Statistical Mechanics (cond-mat.stat-mech)
Can slow recombination in ordered superconductors explain the excess quasiparticle population?
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Eva Gurra, Douglas A. Bennett, Shannon M. Duff, Michael R. Vissers, Joel N. Ullom
An excess density of quasiparticles is widely observed in superconducting films. This excess causes performance degradation in a variety of superconducting devices, including decoherence in qubits. In this Letter, we evaluate the hypothesis of [1] that the quasiparticle excess is caused by anomalously slow recombination at low quasiparticle densities due to localization in sub-gap states. We probe the density of states in aluminum and niobium films using current-voltage measurements of tunnel junctions and extract upper bounds on the energy scales of the sub-gap states and gap smearing. With these parameters, we evaluate the recombination times predicted by [1] and find that slow recombination is not predicted to occur at observed quasiparticle densities in aluminumand niobium-based superconducting devices. These results suggest that the quasiparticle excess in ordered superconductors is primarily due to non-thermal sources of quasiparticle generation and not slow recombination.
Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Spontaneous Cholesteric Phase in Ferroelectric Nematic Liquid Crystals: Preference for Integer Number of Pitches
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Lincoln Paik, Jonathan V. Selinger
In a ferroelectric nematic liquid crystal, the electrostatic interaction can induce a spontaneous cholesteric helix, even if the material is not chiral. If the liquid-crystal cell is infinitely thick, then the predicted pitch depends continuously on material parameters. Here, we consider how the prediction must be modified in a cell of finite thickness. If the Debye screening length is large enough, we find that the free energy has multiple minima. In these minima, the cholesteric pitch is locked to the cell thickness, so that the cell contains an integer number of pitches. However, if the screening length is smaller, then the cholesteric pitch can vary continuously.
Soft Condensed Matter (cond-mat.soft)
Nonlinear Seebeck effect in Ni${81}$Fe${19}$|Pt at room temperature
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Y. Hirata, T. Kikkawa, H. Arisawa, E. Saitoh
The nonlinear Seebeck effect, nonlinear conversion of a temperature gradient into an electric current, was observed at room temperature. Based on a second-harmonic lock-in method combined with an a.c. temperature gradient, $ \nabla T$ , we measured a nonlinear Seebeck voltage in NiFe|Pt bilayers at 300 K, the amplitude of which increases in proportion to $ (\nabla T)^2$ . We also observed that the nonlinear Seebeck voltage increases as the sample length along the $ \nabla T$ direction decreases, showing a characteristic scaling law distinct from the conventional linear Seebeck effect. We developed a phenomenological model for the nonlinear Seebeck effect incorporating the spin-current induced modulation of the Seebeck coefficient, which well reproduces the experimental results.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Appl. Phys. Lett. 126, 252408 (2025)
Impact of charge-density-wave pattern on the superconducting gap in V-based kagome superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
T. Nagashima, K. Ishihara, Y. Yamakawa, F. Chen, K. Imamura, M. Roppongi, R. Grasset, M. Konczykowski, B. R. Ortiz, A. C. Salinas, S. D. Wilson, R. Tazai, H. Kontani, K. Hashimoto, T. Shibauchi
Kagome metals $ A$ V$ _3$ Sb$ _5$ ($ A=$ K, Rb, Cs) provide a compelling platform to explore the interplay between superconductivity (SC) and charge-density-wave (CDW) orders. While distinct CDW orders have been identified in K/RbV$ _3$ Sb$ _5$ versus CsV$ _3$ Sb$ _5$ , their influence on the SC order parameter remains unresolved. Here, we investigate low-energy quasiparticle excitations in $ A$ V$ _3$ Sb$ _5$ , uncovering a striking difference in SC gap anisotropy: K/RbV$ _3$ Sb$ _5$ exhibit fully gapped, nearly isotropic $ s$ -wave states, in contrast to the strongly anisotropic SC gap in CsV$ _3$ Sb$ _5$ . Contrary to previous vortex-state studies suggesting nodal SC in K/RbV$ _3$ Sb$ _5$ , our Meissner-state measurements in high-quality crystals demonstrate fully gapped states with reduced anisotropy compared to CsV$ _3$ Sb$ _5$ . Impurity scattering introduced via electron irradiation in K/RbV$ _3$ Sb$ 5$ has a minimal impact on low-energy excitations, and it induces an increase in the SC transition temperature $ T{\rm c}$ , consistent with more isotropic $ s$ -wave SC competing with CDW order. Our theoretical analysis attributes the observed SC gap anisotropy differences to distinct CDW modulation patterns: the star-of-David structure unique to CsV$ _3$ Sb$ 5$ preserves van Hove singularities near the Fermi level, promoting anisotropic $ s$ -wave SC with enhanced $ T{\rm c}$ via bond-order fluctuations. These findings establish a systematic framework for understanding the interplay between SC and CDW orders in $ A$ V$ _3$ Sb$ _5$ , driven by electron correlations.
Superconductivity (cond-mat.supr-con)
22 pages, 4 figures
Determining the complex second-order optical susceptibility in macroscale van der Waals heterobilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Zeyuan Zhu, Taejun Yoo, Kanchan Shaikh, Amalya C. Johnson, Qiuyang Li, Fang Liu, Hui Deng, Yuki Kobayashi
We report on the experimental characterization of the second-order susceptibility in MoSe$ _2$ /WS$ _2$ heterobilayers, including their hidden complex phases. To this end, we developed a heterodyne-detection scheme for second-harmonic generation and applied it to macroscale heterobilayer samples prepared using the gold-tape exfoliation method. The heterodyne scheme enabled us to distinguish the relative orientation of the crystal domains, and further, it allowed us to characterize the complex phases of the susceptibility relative to a reference quartz sample. By comparing the results from the monolayer regions and the heterobilayer region over several hundred microns of the sample area, we determined that the contribution of interlayer effects to second-harmonic generation is within the experimental uncertainty arising from the sample inhomogeneity. The results here provide fundamental quantitative information necessary for the precise design of nanophotonic systems based on stacking engineering.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Metallic NbS2 one-dimensional van der Waals heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Wanyu Dai, Yongjia Zheng, Akihito Kumamoto, Yanlin Gao, Sijie Fu, Sihan Zhao, Ryo Kitaura, Esko I. Kauppinen, Keigo Otsuka, Slava V. Rotkin, Yuichi Ikuhara, Mina Maruyama, Susumu Okada, Rong Xiang, Shigeo Maruyama
This study presents the experimental realization of metallic NbS2-based one-dimensional van der Waals heterostructures applying a modified NaCl-assisted chemical vapor deposition approach. By employing a “remote salt” strategy, precise control over NaCl supply was achieved, enabling the growth of high-quality coaxial NbS2 nanotubes on single-walled carbon nanotube-boron nitride nanotube (SWCNT-BNNT) templates. With the remote salt strategy, the morphologies of as synthesized NbS2 could be controlled from 1D nanotubes to suspended 2D flakes. Structural characterization via high-resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy (STEM) confirms the formation of crystalline NbS2 nanotubes, revealing a distinct bi-layer preference compared to monolayer-dominated semiconducting transition metal dichalcogenide analogs. Optical analyses using UV-vis-NIR and FTIR spectroscopy highlight the metallic nature of NbS2. With Raman analysis, oxidation studies demonstrate relative higher degradation rate of 1D NbS2 under ambient conditions. Density functional theory (DFT) calculations further elucidate the stabilization mechanism of bi-layer NbS2 nanotubes, emphasizing interlayer charge transfer and Coulomb interactions. This work establishes a robust framework for synthesizing metallic 1D vdW heterostructures, advancing their potential applications in optoelectronics and nanodevices.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Magnetic, charge and orbital properties of parent and Sr-doped La$_2$NiO$_4$ and its pressure evolutions
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Han-Yu Wang, Shu-Hong Tang, Xiao-Teng Huang, Ya-Min Quan, XianLong Wang, Yan-Ling Li, Da-Yong Liu, H.-Q. Lin, Zhi Zeng, Liang-Jian Zou
Recent discovery of unconventional superconductivity on multilayer nickelates under high pressure have stimulated great interest. The magnetic and charge configurations in the normal phase of multilayer nickelates which closely relate to the spin-charge fluctuations remain under strongly debated. In this work, we focus the normal-state magnetic, charge and orbital configurations and its evolutions with hydrostatic pressure and Sr-doping concentration of monolayer nickelate La$ _2$ NiO$ _4$ . We reveal that in the ambient pressure tetragonal La2NiO4 displays Neel-type antiferromagnetic order in planer Ni spins with negligible interlayer magnetic coupling; with the increase of pressure, La2NiO4 evolves from insulate into metallic state with the critical pressure about P = 50 GPa; with the substitution of La by Sr, the magnetic ground state evolves from G-type, A-type, to double spin striped antiferromagnetic states, as well as weak charge and orbital orders, at x=1; These results can greatly promote our understanding of the magnetic properties of Ruddlesden-Popper nickelates, and shed the light of the pairing mechanism of unconventional nickelate superconductors.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Multi-gap and high-Tc superconductivity in metal-atom-free borocarbides: Effects of dimensional confinement and strain engineering
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Hao-Dong Liu, Wei-Yi Zhang, Zhen-Guo Fu, Bao-Tian Wang, Hong-Yan Lu, Hua-Jie Song, Ning Hao, Ping Zhang
Pure borocarbides suffer from limited superconducting potential due to intrinsic structural instability, requiring transition/alkali metals as dual-functional stabilizers and dopants. Here, by combining high-throughput screening with anisotropic Migdal-Eliashberg (aME) theory, we identify dynamically stable borocarbides where high-Tc superconductivity predominately originates from E symmetry-selective electron-phonon coupling (EPC). The six distinct superconducting gaps emerge from a staircase distribution or uncoupling of EPC strength across each Fermi surface (FS) sheet, constituting a metal-free system with such high gap multiplicity. Crucially, dimensional reduction from bulk to surface strengthens E-symmetry EPC and enhances Tc from 32 K (3D bulk) to 75 K (2D surface), a result that highlights structural confinement as a key design strategy for observing high Tc. External strain further optimizes the competition between EPC strength and characteristic phonon frequency to achieve Tc > 90 K. This work reveals a systematic correlation between structural dimensionality and gap multiplicity and establishes borocarbide as a tunable platform to engineer both high-Tc and multi-gap superconductivity.
Superconductivity (cond-mat.supr-con)
Evidence of topological Kondo insulating state in MoTe2/WSe2 moiré bilayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Zhongdong Han, Yiyu Xia, Zhengchao Xia, Wenjin Zhao, Yichi Zhang, Kenji Watanabe, Takashi Taniguchi, Jie Shan, Kin Fai Mak
Topological Kondo insulators (TKIs) are topologically protected insulating states induced not by single-particle band inversions, but by the Kondo interaction between itinerant electrons and a lattice of local magnetic moments. Although experiments have suggested the emergence of three-dimensional (3D) TKIs in the rare earth compound SmB6, its two-dimensional (2D) counterpart has not been demonstrated to date. Here we report experimental evidence of a TKI in angle-aligned MoTe2/WSe2 moiré bilayers, which support a Kondo lattice with topologically nontrivial Kondo interactions. We prepare in a dual-gated device a triangular lattice Mott insulator in the MoTe2 layer Kondo-coupled to a half-filled itinerant band in the WSe2 layer. Combined transport and compressibility measurements show that the prepared state supports metallic transport at high temperatures and, at low temperatures, an insulating bulk with conducting helical edge states protected by spin-Sz conservation. The presence of Kondo singlets is further evidenced by their breakdown at high magnetic fields. Such behaviors are in stark contrast to the simple metallic state when the Mott insulator in the MoTe2 layer is depleted by gating. Our results open the door for exploring tunable topological Kondo physics in moiré materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Synthesis and transport properties of epitaxial Bi (0001) films on GaAs (111) substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Jagannath Jena, Eugene Ark, Justin Wood, Junyi Yang, John Pearson, Hanu Arava, Daniel Rosenmann, U. Welp, J. S. Jiang, Deshun Hong, Anand Bhattacharya
In recent decades, the growth of ultrathin epitaxial bismuth (Bi) films on various substrates has garnered interest due to their topological, thermoelectric, and even ferroelectric properties. We report upon the growth and transport properties of epitaxial Bi (0001) films in the thickness range of 5-32 nm deposited directly on GaAs (111) substrates, without a buffer layer. The quality of Bi films are found to depend on conditions for substrate treatment using Ar+ ion-milling and annealing. Substrates milled at low ion beam currents display poor surface reconstruction after annealing, which hinders the growth of high-quality films. In contrast, substrates milled under optimized conditions led to reconstructed surfaces upon annealing, resulting in epitaxial Bi films with predominantly single-domain orientation. Although epitaxial films formed in both cases, transport measurements indicated significantly higher conductivity for films grown on optimally treated substrates. Measurements at low temperatures suggest that the transport properties are dominated by a surface state. Magneto-transport measurements suggest that conductivity and mobility improve progressively with increasing film thickness. Remarkably, our 5 nm Bi film demonstrated resilience to ambient conditions without oxidation, with transport properties similar to those of bilayer Bi films grown by confinement heteroepitaxy in other studies. These results provide a robust methodology for growing high-quality epitaxial Bi films on GaAs (111) and offer insights into their unique transport properties.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
$Σ$3(111) Grain Boundaries Accelerate Hydrogen Insertion into Palladium Nanostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
K. A. U. Madhushani (1), H. Park (2), H. Zhou (3), D. D. Mal (1), Q. Pang (2), D. Li (2), P. V. Sushko (2), L. Luo (1) ((1) Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA, (2) Physical & Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, USA, (3) X-Ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA)
Grain boundaries (GBs) are frequently implicated as key defect structures facilitating metal hydride formation, yet their specific role remains poorly understood due to their structural complexity. Here, we investigate hydrogen insertion in Pd nanostructures enriched with well-defined $ \Sigma$ 3(111) GBs (Pd GB) synthesized via electrolysis-driven nanoparticle assembly. In situ synchrotron X-ray diffraction reveals that Pd GB exhibits dramatically accelerated hydriding and dehydriding kinetics compared to ligand-free and ligand-capped Pd nanoparticles with similar crystallite sizes. Strain mapping using environmental transmission electron microscopy shows that strain is highly localized at GBs and intensifies upon hydrogen exposure, indicating preferential hydrogen insertion along GB sites. Density functional theory calculations support these findings, showing that hydrogen insertion near $ \Sigma$ 3(111) GBs is energetically more favorable and that tensile strain lowers insertion barriers. These results provide atomic-level insights into the role of GBs in hydride formation and suggest new design strategies for GB-engineered Pd-based functional materials. Keywords: Hydrogen Insertion; Tensile Strain; Grain Boundaries; Palladium Nanostructures.
Materials Science (cond-mat.mtrl-sci)
Anomalous Charge Density Wave and Fermi Surface Reconstruction in Pressurized BaFe2Al9
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Govindaraj Lingannan, M. Sundaramoorthy, Nabeel M. Jasim, I. K. Abbas, C. S. Lue, Leon F. Carstens, A. Bertrand, M. Mito, B. Joseph, Rüdiger Klingeler, S. Arumugam, Mahmoud Abdel-Hafiez
The intermetallic compound BaFe2Al9 exhibits unusual physical properties associated with a charge density wave (CDW) transition. Unlike conventional CDW materials, which typically display subtle structural distortions or lattice modulations, BaFe2Al9 undergoes a first-order phase transition in which lattice strain plays a crucial role in the formation of the CDW state. To further explore this unique behavior, we conducted high-pressure studies, examining the electrical transport, magnetic, and structural properties to gain deeper insight into the underlying CDW mechanism. At ambient pressure, electrical resistivity and magnetization measurements confirm the presence of a CDW transition. Upon applying pressure, the CDW transition temperature (TCDW) shifts to higher values, reaching approximately 300 K near 3.2 GPa, and the electrical resistivity increases, suggesting that pressure modulates the charge carrier concentration. Furthermore, the initially sharp first-order transition becomes more gradual, and analysis of the temperature derivative of resistivity indicates a crossover from first-order to second-order like behavior under pressure. High-pressure magnetization measurements are consistent with the electrical transport data, showing an enhancement of TCDW with increasing pressure. The residual resistivity increases with pressure, while the Fermi liquid coefficient A decreases above 2 GPa, pointing to a possible Fermi surface reconstruction. High-pressure synchrotron powder X-ray diffraction (XRD) measurements at room temperature reveal a lattice anomaly near 3.8 GPa, marked by a distinct trend change in macrostrain, further supporting the existence of a pressure induced structural response. These findings provide valuable insight into the nature of CDW formation in BaFe2Al9 and highlight the critical role of lattice strain and external pressure in tuning its electronic ground state.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
19 pages with SI materials
Quantized Topological States and Parity Anomaly in Intrinsic Quantum Anomalous Hall Insulator MnBi2Te4
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Zhongxun Guo, Jingjing Gao, Zhiwei Huang, Di Yue, Zhaochen Liu, Mingyan Luo, Shuang Wu, Xinyu Chen, Guangyi Huang, Yujun Deng, Mengzhu Shi, Yin Xia, Zihan Xu, Chuanying Xi, Guangli Kuang, Changlin Zheng, Shiwei Wu, Hua Jiang, X. C. Xie, Wenzhong Bao, Yuping Sun, Xian Hui Chen, Jing Wang, Wei Ruan, Yuanbo Zhang
When thinned down to just a few atomic layers, the layered magnetic topological insulator MnBi2Te4 offers an exceptional platform for exploring a wide range of topological phenomena. In this work, we overcome longstanding challenges in synthesizing high-purity MnBi2Te4 crystals and report the observation of a myriad of quantized topological states in high-quality five-septuple-layer (5-SL) samples under magnetic fields up to 45 Tesla. We show that the nontrivial topology of 5-SL MnBi2Te4, in the presence of Landau quantization, is governed by a generalized topological index rooted in the parity anomaly of Dirac fermions in (2+1) dimensions. The anomaly manifests as an anomalous Landau level, giving rise to gate-tunable helical edge transport. Our results establish high-quality MnBi2Te4 as a robust platform for exploring emergent topological states and for advancing novel quantum device applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
13 pages,4 figures
Incipient ionic conductors: Ion-constrained lattices achieving superionic-like thermal conductivity by extreme anharmonicity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Yongheng Li, Chunqiu Lu, Bin Wei, Cong Lu, Xingang Jiang, Daisuke Ishikawa, Taishun Manjo, Caofeng Pan, Alfred Q. R. Baron, Jiawang Hong
Phonon liquid-like thermal conduction in the solid state enables superionic conductors to serve as efficient thermoelectric device candidates. While liquid-like motion of ions effectively suppresses thermal conductivity (\kappa), their high mobility concurrently triggers material degradation due to undesirable ion migration and consequent metal deposition, making it still a challenge to balancing low \kappa and high stability. Here, we report a superionic-like thermal transport alongside restricted long-range ion migration in CsCu_2I_3 with incipient ionic conduction, using synchrotron X-ray diffraction, inelastic X-ray scattering, and machine-learning potential-based simulations. We reveal that the Cu ions exhibit confined migration between CuI_4 tetrahedra at high temperatures, displaying extreme anharmonicity of dominated phonons beyond conventional rattling and comparable to that in superionic conductorsl. Consequently, a glass-like \kappa (~0.3 W m^{-1} K^{-1} at 300 K) following the relationship of \kappa ~ T^{0.17}, was achieved along the x-direction, where Cu ion migration is three oders of magnitude lower than in superionic conductors. These results highlight the advantage of incipient ionic conductors in simultaneously maintaining both low \kappa and high stability, elucidate the thermal transport mechanism via ion migration constraints, and pave an effective pathway toward ultralow thermal conductivity in ionic conductors.
Materials Science (cond-mat.mtrl-sci)
24 pages, 5 figures
Multiscale Modeling of Vacancy-Cluster Interactions and Solute Clustering Kinetics in Al-Mg-Zn Alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Zhucong Xi, Louis G. Hector Jr., Amit Misra, Liang Qi
During heat treatment of age-hardenable alloys, growing solute clusters can strongly trap excess vacancies, limiting their mobility and significantly influencing precipitation kinetics. However, quantitative understanding of vacancy-cluster interactions remains limited due to the inherently multi-time- and multi-length-scale nature of vacancy-mediated diffusion. In this work, we develop an integrated computational framework combining lattice kinetic Monte Carlo (KMC) simulations, an atomistic absorbing Markov chain model, and mesoscale cluster dynamics (CD) to investigate these interactions and predict their effects on long-time clustering in Al-Mg-Zn alloys. The Markov chain model yields vacancy escape times from solute clusters and identifies a two-stage behavior of the vacancy-cluster binding energy: a size-dependent regime for small clusters (fewer than $ \sim$ 100 atoms), followed by a saturation stage governed by vacancy formation energy differences between the cluster and matrix. These binding energies are used to estimate residual mobile vacancy concentrations in the Al matrix after quenching, which serve as critical inputs to CD simulations to predict the long-time cluster evolution kinetics during natural aging. Our results quantitatively demonstrate that cooling rate substantially affects natural aging kinetics, offering predictive insights for tailoring heat treatments in engineering alloys.
Materials Science (cond-mat.mtrl-sci)
Ferroelectric Antiferromagnetic Lifting of Spin-Valley Degeneracy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Jiaqi Feng, Xiaodong Zhou, Jingyan Chen, Meiling Xu, Xiuxian Yang, Yinwei Li
The generation and control of spin- and valley-polarization in antiferromagnets (AFMs) have garnered increasing attention due to their potential for enabling faster and more stable multifunctional spintronic and valleytronic memory and logic devices. However, the two primary categories of AFMs, altermagnets and TP-symmetric AFMs, either lack intrinsic valley-polarization or net spin-polarization. Here, we propose an effective approach for achieving spontaneous spin-valley polarization in TP-broken layered ferroelectric antiferromagnets (FE-AFMs). The FE-AFMs exhibit lifted spin degeneracy across the entire Brillouin zone, along with uncompensated spin density of states. They combine the benefits of spin-polarization in altermagnets with valley-polarization in TP-symmetric AFMs. Furthermore, the FE-AFMs feature layer-dependent spin-polarization, rooted in their intrinsic ferroelectric property, allowing for the flexible control over spin-valley polarization by interlayer sliding. This tunability facilitates sign-reversible and size-tunable valley Hall and Nernst effects, along with other spin-valley-dependent transport properties. Our findings are demonstrated in a broad class of TP-broken bilayer antiferromagnets such as Nb3X8 (X = Cl, Br, I), VX2 (X = S, Se), and VSi2X4 (X = N, P), underscoring the potential of FE-AFMs for advancing next-generation spin- and valley-based information technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
11 pages
Physical Review B 111, 214446 (2025)
Magnetic field induced exciton spin dynamics in indirect band gap (In,Al)As/AlAs quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
T.S. Shamirzaev, D. R. Yakovlev, D. S. Smirnov, V. N. Mantsevich, D. Kudlacik, A. Yu. Gornov, A. K. Gutakovskii, M. Bayer
The exciton recombination and spin dynamics are investigated both experimentally and theoretically in an ensemble of indirect band gap (In,Al)As/AlAs quantum dots (QDs) with type-I band alignment. The magnetic-field-induced circular polarization of the time-integrated photoluminescence changes sign across the emission spectrum with a width reflecting the QD size. It is negative on the low energy side, i.e. for emission from large QDs, but positive on the high energy side, i.e. for emission from small QDs. However, the exciton g factor, measured by spin-flip Raman scattering, is positive across the whole QD ensemble. The magnetic-field-induced circular polarization of the photoluminescence dynamics is studied as function of the magnetic field strength and direction. The dynamics are non-monotonic over a time range up to milliseconds. The time dependence of the photoluminescence circular polarization degree and sign strongly depends on the emission energy and changes with magnetic field orientation. The observed nonmonotonic behavior is provided by the interplay of bright and dark exciton states, contributing to the emission. The experiment is interpreted using a kinetic theory, which accounts for the dynamics of the spin states in the exciton level quartet in longitudinal and tilted magnetic fields, the radiative recombination processes, and the redistribution of the excitons between these states as result of spin relaxation. The model allows us to evaluate the electron and heavy hole spin relaxation times in QDs with different sizes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
Index Theorem and Vortex Kinetics in Bose-Einstein Condensates on a Haldane Sphere with a Magnetic Monopole
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Xi-Yu Chen, Lijia Jiang, Tao Yang, Jun-Hui Zheng
The geometry-gauge interplay constitutes a fundamental issue in quantum physics, with profound implications spanning from quantum gravity to topological matter. Here, we investigate the dynamic effects of geometry-gauge interplay in Bose-Einstein condensates (BECs) on a Haldane sphere with a magnetic monopole. We reveal an index theorem that establishes a correspondence between BEC vortices and the topology of the gauge field, enabling the construction of vortex-monopole composites. Furthermore, we derive the universal logarithmic interaction between composites, which governs the structure of the ground-state vortex lattice. By developing a kinetic theory, we predict scale-invariant vortex dynamics and an emergent duality. Both are confirmed through numerical simulations. This work first presents the dynamical coupling mechanism between spatial geometry and gauge fields, providing deep insights into superfluid systems with topological gauge structures in curved space.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS), Quantum Physics (quant-ph)
10 pages, 3 figures
Variable-Temperature Plasmonic High-Entropy Carbides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Simon Divilov, Sean D. Griesemer, Robert C. Koennecker, Michael J. Ammendola, Adam C. Zettel, Hagen Eckert, Jeffrey R. Shallenberger, Xiomara Campilongo, William G. Fahrenholtz, Arrigo Calzolari, Douglas E. Wolfe, Stefano Curtarolo
Effective thermal management at variable and extreme temperatures face limitations for the development of novel energy and aerospace applications. Plasmonic approaches, shown to be capable of tailoring black-body emission, could be effective if materials with high-temperature and tunable plasmonic-resonance were available. Here, we report a synergy between experimental and theoretical results proving that many high-entropy transition-metal carbides, consisting of four or more metals at equal molar ratio, have plasmonic resonance at room, high (>1000C) and variable temperatures. We also found that these high-entropy carbides can be tuned and show considerable plasmonic thermal cycling stability. This paradigm-shift approach could prove quite advantageous as it facilitates the accelerated rational discovery and manufacturability of optically highly-optimized high-entropy carbides with ad-hoc properties.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
12 Pages, 7 Fugures, High Entropy Alloys and Materials (2025)
Anharmonicity and Coulomb Pseudopotential Effects in YH$_6$ and YH$_9$ Superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Yucheng Ding, Haoran Chen, Junren Shi
Anharmonic effects are widely believed to be the primary cause of the overestimation of superconducting transition temperatures of yttrium hydrides YH$ _6$ and YH$ _9$ in theoretical predictions. However, prior studies indicate that anharmonicity alone may be insufficient to account for this discrepancy. In this work, we employ the stochastic path-integral approach to investigate the quantum and anharmonic effects of ions in yttrium hydrides. Our calculations reveal significant corrections to the electron-phonon coupling parameters and an increase in the average phonon frequency compared to density functional perturbation theory, aligning closely with results from the stochastic self-consistent harmonic approximation. We find that properly taking into account the renormalization of the Coulomb pseudopotential due to the frequency cutoff, which is often overlooked in previous calculations, is critical to predicting transition temperatures consistent with experimental values for both YH$ _6$ and YH$ _9$ . This indicates that, with this correction, anharmonic effects are sufficient to explain the discrepancies between experimental and theoretical results.
Superconductivity (cond-mat.supr-con)
7 pages, 5 figures
Brownian motion near a soft surface
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Yilin Ye (LOMA, LPMC), Yacine Amarouchene (LOMA), Raphaël Sarfati (CU), David S. Dean (LOMA), Thomas Salez (LOMA)
Brownian motion near soft surfaces is a situation widely encountered in nanoscale and biological physics. However, a complete theoretical description is lacking to date. Here, we theoretically investigate the dynamics of a two-dimensional colloid in an arbitrary external potential and near a soft surface. The latter is minimally modelled by a Winkler’s foundation, and we restrict the study to the colloidal motion in the direction perpendicular to the surface. We start from deterministic hydrodynamic considerations, by invoking the already-established leading-order soft-lubrication forces acting on the particle. Importantly, a negative softness-induced and position-dependent added mass is identified. We then incorporate thermal fluctuations in the description. In particular, an effective Hamiltonian formulation is introduced and a temperature-dependent generalized potential is constructed in order to ensure equilibrium properties for the colloidal position. From these considerations and the Fokker-Planck equation, we then derive the relevant Langevin equation, which self-consistently allows to recover the deterministic equation of motion at zero temperature. Interestingly, besides an expected multiplicative-noise feature, the noise correlator appears to be modified by the surface softness. Moreover, a softness-induced temperature-dependent spurious drift term has to be incorporated within the Ito prescription. Finally, using numerical simulations with various initial conditions and parameter values, we statistically analyze the trajectories of the particle when placed within a harmonic trap and in presence of the soft surface. This allows us to: i) quantify further the influence of surface softness, through the added mass, which enhances the velocity fluctuations; and ii) show that intermediate-time diffusion is unaffected by softness, within the assumptions of the model.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Structural and Magnetic Properties of Barium Hexaferrite Nanoplatelets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Daniel Zabek, Joseph Veryard, Yusra Ahmed, Arjen van den Berg, Joseph Askey, Sam Ladak
Combining unique geometric and magnetic anisotropy in barium hexaferrites has the potential to enhance the performance of advanced technological applications, such as data storage, spintronics, and medicine. Here, we report the synthesis and deposition of barium hexaferrite nanoplatelets, followed by comprehensive structural and magnetic microscopies. The topographic, physical, and morphological properties of individual nanoplatelets, clusters, and aggregates are analyzed using atomic force microscopy (AFM) and electron microscopy, while magnetic properties are analysed using magnetic force microscopy (MFM). Relevant size distributions and nanoparticle configurations for magnetic interactions have been experimentally identified and numerically analyzed. For dense nanoparticle arrangements, direct exchange coupling dominates with parallel magnetisation configuration in overlapping particles. In contrast, separated particles exhibit anti-parallel coupling. Detailed micro-magnetic modelling elucidates the length scales over which these two interaction regimes are dominant, paving the way for macroscopic two-dimensional (2D) and three-dimensional (3D) structures with tuned magnetic ordering.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Vacancy-free cubic superconducting NbN enabled by quantum anharmonicity
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Eva Kogler, Mihir R. Sahoo, Chia-Nien Tsai, Fabian Jöbstl, Roman Lucrezi, Peter I. C. Cooke, Birgit Kunert, Roland Resel, Chris J. Pickard, Matthew N. Julian, Rohit P. Prasankumar, Mahmoud I. Hussein, Christoph Heil
Niobium nitride (NbN) is renowned for its exceptional mechanical, electronic, magnetic, and superconducting properties. The ideal 1:1 stoichiometric $ \delta$ -NbN cubic phase, however, is known to be dynamically unstable, and repeated experimental observations have indicated that vacancies are necessary for its stabilization. In this work, we demonstrate that when the structure is fully relaxed and allowed to distort under quantum anharmonic effects, a previously unreported stable cubic phase with space group $ P\bar{4}3m$ emerges - 65 meV/atom lower in free energy than the ideal $ \delta$ phase. This discovery is enabled by state-of-the-art first-principles calculations accelerated by machine-learned interatomic potentials. To evaluate the vibrational and superconducting properties with quantum anharmonic effects accounted for, we use the stochastic self-consistent harmonic approximation (SSCHA) and molecular dynamics spectral energy density (SED) methods. Electron-phonon coupling calculations based on the SSCHA phonon dispersion yield a superconducting transition temperature of $ T_\text{c}$ = 20 K, which aligns closely with experimentally reported values for near-stoichiometric NbN. These findings challenge the long-held assumption that vacancies are essential for stabilizing cubic NbN and point to the potential of synthesizing the ideal 1:1 stoichiometric phase as a route to achieving enhanced superconducting performance in this technologically significant material.
Superconductivity (cond-mat.supr-con)
AFLOW4: heading toward disorder
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Simon Divilov, Hagen Eckert, Scott D. Thiel, Sean D. Griesemer, Rico Friedrich, Nicholas H. Anderson, Michael J. Mehl, David Hicks, Marco Esters, Nico Hotz, Xiomara Campilongo, Arrigo Calzolari, Stefano Curtarolo
AFLOW4 is the latest iteration of the AFLOW toolkit, specifically tailored to study high-entropy disordered materials. This upgrade includes innovative features like the Soliquidy module, based on the Euclidean transport cost between disordered and ordered material states. AFLOW4 can calculate dielectric functions to understand optical and electronic properties of disordered ceramics. The newly introduced human-readable data export feature ensures the uncomplicated incorporation of AFLOW4 in diverse automated workflows. Features relevant to high-entropy research, like prototype identification, partial occupation method, convex hull calculation, and enthalpy corrections based on local atomic environments, have been improved and exhibit substantial speed-up. Together, these enhancements represent a step forward for AFLOW as a valuable tool for research of high-entropy materials.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Computational Physics (physics.comp-ph)
9 pages, 6 figures
High Entropy Alloys & Materials (2025)
Enhancing thermoelectric efficiency of multilayer graphene by nanomeshing
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Mehrdad Rahimi, Nunzia Lubertino, Roberto Bellelli, Linsai Chen, François Mallet, Philippe Lafarge, Clément Barraud, PAscal Marti, Julien Chaste, Danièle Fournier, Maria Luisa Della Rocca
Nanostructuring materials at small scales enables control over their physical properties, revealing behaviors not observed at larger dimensions. This strategy is particularly effective in two-dimensional (2D) materials, where surface effects dominate, and has been applied in the thermoelectric field. Here, we use multilayer graphene (4-6 nm thick) as a test platform to study the effect of nanomeshing on its thermoelectric properties. The nanomesh consists of a hexagonal array of holes, with a measured diameter and neck-width of ~360 nm and ~160 nm, respectively. The multilayer graphene is integrated into field-effect transistor-like devices supported by hexagonal boron nitride (hBN), allowing simultaneous electric and thermoelectric measurements, with nanomeshing applied to only part of the material. We use modulated thermoreflectance to investigate thermal transport in equivalent nanomeshed and pristine graphene flakes, extracting key parameters that affect thermoelectric performance. The nanomesh geometry suppresses thermal transport without significantly impacting charge transport, highlighting the different scattering lengths of phonons and electrons while enhancing the thermopower response. We observe a twofold improvement in the device power factor, PF = S^2 sigma (with S the Seebeck coefficient and sigma the electrical conductivity), at room temperature, along with a nearly threefold reduction in thermal conductivity k. The results show that nanomeshing can significantly improve the thermoelectric performance of multilayer graphene, paving the way for novel energy conversion strategies using 2D materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
10 pages, 4 figures
Room temperature magnetic vortices in the van der Waals magnet Fe$_5$GeTe$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Elias Sfeir, Carolin Schrader, Florentin Fabre, Jules Courtin, Céline Vergnaud, Alain Marty, Matthieu Jamet, Frédéric Bonell, Isabelle Robert-Philip, Vincent Jacques, Aurore Finco
We investigate the effect of confinement on the magnetic state of a 12 nm-thick Fe$ _5$ GeTe$ _2$ layer grown by molecular beam epitaxy. We use quantitative scanning NV magnetometry to locally extract the magnetization in rectangular uniformly in-plane magnetized microstructures, showing no enhancement of the Curie temperature compared to magnetization measurements performed before patterning the film, in contrast to previous results obtained on thick Fe$ _3$ GeTe$ _2$ flakes. Under the application of a weak out-of-plane magnetic field, we observe the stabilization of magnetic vortices at room temperature in micrometric squares. Finally, we highlight the effect of the size of the patterned micro-discs and micro-squares on the stabilization of the vortices using experiments and micromagnetic simulations. Our work thus proposes and demonstrates a way to stabilize non-collinear textures at room temperature in a van der Waals magnets using confinement, although we also show that this approach alone is not successful to enhance the Curie temperature of Fe$ _5$ GeTe$ _2$ significantly above 300 K.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures, supplement as ancillary file
An alternative approach to the phonon theory of liquids: An analytical study of Frenkel frequency and heat capacity as a function of pressure and temperature
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
M. Y. Esmer, Bahtiyar A. Mamedov
Based on the Maxwell relationship and experimental viscosity data, the phonon theory of liquids can provide a temperature-dependent description of liquid heat capacity that is consistent with experimental data. However, since liquid heat capacity also varies with pressure, we present an alternative approach that can be used to calculate the Frenkel frequency in terms of temperature and pressure by applying the concept of chemical potential under the assumption of a diffusive equilibrium. Using this derived Frenkel frequency, we formulate an analytical expression for the liquid heat capacity in terms of both temperature and pressure, without the need for viscosity data, which is consistent with predictions from the phonon theory of liquids. Our model is tested by comparing the calculated heat liquid capacity with experimental data for four noble liquids at various pressures and temperatures, and good agreement is found. Finally, based on our findings, we propose analytical expressions for the Frenkel line and viscosity as a function of pressure and temperature, and discuss the key details and implications of our approach.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
From localized 4f electrons to anisotropic exchange interactions in ferromagnetic CeRh6Ge4
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Shoichiro Itokazu, Akimitsu Kirikoshi, Harald O. Jeschke, Junya Otsuki
CeRh6Ge4 is a Ce-based ferromagnetic material exhibiting a quantum critical behavior under pressure. We derive effective exchange interactions, using the framework of density functional theory combined with dynamical mean-field theory. Our results reveal that the nearest-neighbor ferromagnetic interaction along the c-axis is isotropic in spin space, leading to a formation of spin chains. On the other hand, the inter-chain coupling is highly anisotropic: The in-plane moment weakly interacts ferromagnetically in the a–b plane to stabilize the ferromagnetic state, whereas the z-component couples antiferromagnetically, contributing to its destabilization. The magnetic anisotropy of the interchain interactions as well as of the local 4f wavefunctions characterizes the magnetic properties underlying the ferromagnetic transition and the quantum critical behavior in CeRh6Ge4.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
9 pages, 6 figures
Magnetocalorics of singlet ground state induced moment magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
In f-electron materials like Pr or U compounds with non-Kramers states of the f-shell the ground state may be a nonmagnetic singlet due to the action of the crystalline electric field. Nevertheless these compounds can order magnetically. They develop a ground state moment and long range order due to the spontaneous admixture of the excited state into the ground state caused by inter-site exchange. This mechanism can establish magnetic order if a control parameter exceeds a critical value defining the quantum critical point between disordered and magnetic phase. Here we investigate the magnetocaloric properties of such quantum magnets where the entropy release at low temperature is due to a competition between thermal depopulation and spontaneous order effects. We determine field and temperature dependence of specific heat for ferro- and antiferromagnetic order and also calculate the adiabatic magneto- and barocaloric cooling rates. As a model application we discuss the magnetic specific heat of the new induced ferromagnet PrI3. Furthermore we analyze the excitation spectrum of the singlet induced moment magnets in an external field with particular emphasis on field and temperature dependence of the critical soft mode. We find that the latter is fragile and exists only at specific points in the phase diagram.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages,12 figures
A Molecule with Half-Möbius Topology
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Igor Roncevic, Fabian Paschke, Yueze Gao, Leonard-Alexander Lieske, Lene A. Gödde, Jascha Repp, Florian Albrecht, Harry L. Anderson, Leo Gross
Stereoisomers of C13Cl2 exhibiting helical orbitals around a ring of carbon atoms were synthesized by atom manipulation. We resolved chiral geometries of the closed-shell singlet states by atomic force microscopy and mapped helical orbital densities by scanning tunnelling microscopy. The {\pi}-orbital basis of the singlets twists by 90° in one circulation, which is consistent with a half-Möbius topology. In such a topology, the {\pi}-orbital basis is periodic with respect to four circumnavigations, corresponding to a quasiparticle on a ring with this boundary condition, implying a Berry phase of {\pi}/2. We demonstrate reversible switching of the topology, between the two singlets of oppositely threaded half-Möbius topology, and the planar, topologically trivial, triplet isomer.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph)
Microscopic origin of the nemato-elastic coupling and dynamics of hybridized collective nematic-phonon excitations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Morten H. Christensen, Michael Schütt, Avraham Klein, Rafael M. Fernandes
Electronically-driven nematic order breaks the rotational symmetry of a system, e.g., through a Pomeranchuk instability of the Fermi surface, with a concomitant distortion of the lattice. As a result, in a metal, the nematic collective mode interacts with two different sets of gapless excitations: the particle-hole excitations of the metal and the lattice fluctuations that become soft at the induced structural transition, namely, the transverse acoustic phonons. However, the \textit{dynamics} of these hybridized collective modes formed by the transverse acoustic phonons and the metallic electronic-nematic fluctuations has remained largely unexplored. Here we address this problem by developing a formalism in which the nemato-elastic coupling is obtained microscopically from the direct coupling between electrons and transverse acoustic phonons enabled by impurities present in the crystal. We then demonstrate the emergence of hybrid nemato-elastic modes that mix the characteristics of the transverse phonons and of the nematic fluctuations. Near the nematic quantum critical point in a metal, two massless modes emerge with intertwined dynamic behaviors, implying that neither mode dominates the response of the system. We systematically study the non-trivial dependence of these collective modes on the longitudinal and transverse momenta, revealing a rich landscape of underdamped and overdamped modes as the proximity to the quantum critical point and the strength of the electron-phonon coupling are changed. Since dynamics play an important role for determining superconducting instabilities, our results have implications for the study of pairing mediated by electronic nematic fluctuations.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
16 pages, 11 figures
Chirality-dependent terahertz topological resonance and inertial dynamics of magnetic skyrmions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
X. D. Wang, Y. F. Duan, H. M. Dong, Kai Chang
We present a theoretical investigation of the terahertz (THz) optical response of magnetic skyrmions governed by an inertial-modified Thiele equation. By incorporating the inertial mass term, we derive analytical expressions for the THz absorption spectrum of skyrmions, revealing a topological resonance phenomenon tunable via the skyrmion’s topological charge $ Q$ , damping factor $ \alpha$ , and effective mass $ m$ . The resonance frequency $ \omega_0 \propto Q/m$ emerges from the interplay between gyroscopic coupling and inertial mass, enabling precise control over skyrmion dynamics through circularly polarized THz fields. Our results demonstrate that the helical motion trajectories and velocity components of skyrmions depend on the chirality of light and the topological charge $ Q$ , with critical damping $ \alpha_c$ marking the transition to overdamped regimes. Our findings establish an optical method for designing tunable THz devices, such as topological filters and detectors, by exploiting the interplay between magnetic skyrmion topology and the chirality of THz light coupling.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
13 pages, 5 figures
Phonon-enhanced optical spin-conductivity and spin-splitter effect in altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Erik Wegner Hodt, Alireza Qaiumzadeh, Jacob Linder
Collinear antiferromagnets with nonrelativistic spin-split bands and no net magnetization, called altermagnets, show interesting transport properties due to their unique band structure. We here compute the linear response optical conductivity of thin films of such materials in the presence of phonon scatterings. Using a tight-binding lattice model for altermagnets and the Holstein model for the phonon sector, we find that the electron-phonon scatterings can strongly increase the spin conductivity at finite frequencies. This occurs despite the fact that the self-energy describing the electron-phonon interactions is spin-independent. Interestingly, we show that electron-phonon scattering also enhances the spin-splitter effect at finite frequencies. These results suggest that altermagnets with strong electron-phonon coupling are favorable with regard to AC spin-polarized transport.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 7 figures
On-chip magnon polaron generation in mode-matched cavity magnomechanics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Daiki Hatanaka, Motoki Asano, Megumi Kurosu, Yoshitaka Taniyasu, Hajime Okamoto, Hiroshi Yamaguchi
Generation of magnon polarons, which are hybridized states resulting from strong magnon-phonon coupling, is a key to enabling coherent manipulation in acoustic and spintronic devices. However, the conventional device configuration, a magnetic thin film on a thick piezoelectric layer, often has difficulty achieving a large magnon-phonon coupling due to a very small spatial mode overlap. Here, we demonstrate generation of magnon polarons by using a mode-matched on-chip magnomechanical system. A configuration with a thin piezoelectric film on a magnetic layer several micrometers thick was found to sustain deeply distributed magnon modes that enable magnetoelastic coupling to phonons over almost the entire mode volume. The enhanced spatial mode overlap generated magnon polarons whose spectra showed distinct avoided crossing. This magnomechanical system will facilitate utilization of coherent magnon-phonon conversion and their hybrid states in functional phononic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 6 figures
Numerical investigation of the equilibrium Kauzmann transition in a two-dimensional atomistic glass
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Gerhard Jung, Misaki Ozawa, Giulio Biroli, Ludovic Berthier
Dense liquids gradually transform into non-equilibrium amorphous solids as they pass through the experimental glass transition. Experimentally, ergodicity is lost because measurements are conducted within a finite time window. More than seventy years ago, Kauzmann posed a fundamental question: If experiments could run indefinitely, would there exist a critical temperature at which an ergodicity-breaking phase transition occurs? Random first-order transitions represent the modern theoretical framework for this idea, rigorously established in the mean-field limit of high-dimensional atomistic systems and several idealized physical models. However, achieving theoretical understanding in finite dimensions is challenging, while experimental and numerical limitations on accessible timescales hinder direct observation of the putative Kauzmann transition. Here, we overcome this longstanding barrier by developing a computational strategy that combines three advanced Monte Carlo methods to access the equilibrium thermodynamic properties of a two-dimensional atomistic glass-former down to zero temperature across a range of system sizes. This enables us to directly measure thermodynamic and structural observables that provide unambiguous evidence that the system undergoes a Kauzmann transition at a temperature that vanishes in the thermodynamic limit. This transition is towards an ideal glass state characterized by a complex energy landscape with a hierarchical organization of low-lying states. Our results are the first demonstration that computer simulations can fully probe the statistical mechanics of the bulk transition to a non-ergodic glass state. We anticipate that our study will serve as a foundation for future simulation work on larger systems, three-dimensional materials, and more complex glass-forming models to fully elucidate the nature of the glass state of matter.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
Andreev bound state spectroscopy of a quantum-dot-based Aharonov-Bohm interferometer with superconducting terminals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Peter Zalom, Don Rolih, Rok Žitko
We analytically and numerically investigate an Aharonov-Bohm interferometer with two superconducting terminals and a strongly correlated quantum dot in one arm. Through a rigorous derivation, we prove that this double-path interferometer is spectrally equivalent to a simpler system: an interacting quantum dot coupled to a non-interacting side-coupled proximitized mode and a semiconductor lead. This equivalence reveals a simple interpretation of the interferometer’s behavior through the competition of a geometric factor $ \chi$ , a key parameter characterizing the anomalous part of the hybridization function, with the properties of the side-coupled mode. We identify the conditions for the formation of doublet chimney in the phase diagrams in more general setting. Moreover, we show how the obtained Andreev bound state spectra clearly indicate the presence of Josephson diode effect generated by interferometric phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
16 pages, 8 figures
Local entropy production rate of run-and-tumble particles
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Matteo Paoluzzi, Andrea Puglisi, Luca Angelani
We study the local entropy production rate and the local entropy flow in active systems composed of non-interacting run-and-tumble particles in a thermal bath. After providing generic time-dependend expressions, we focus on the stationary regime. Remarkably, in this regime the two entropies are equal and depend only on the distribution function and its spatial derivatives. We discuss in details two case studies, relevant to real situations. First, we analyze the case of space dependent speed,describing photokinetic bacteria, cosidering two different shapes of the speed, piecewise constant and sinusoidal. Finally, we investigate the case of external force fields, focusing on harmonic and linear potentials, which allow analytical treatment. In all investigated cases, we compare exact and approximated analytical results with numerical simulations.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
25 pages, 6 figures
Effect of alloying additions on the lattice ordering of Ti$_2$AlNb intermetallic
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Adilakshmi Chirumamilla, Gopalakrishnan Sai Gautam
Alloys based on the orthorhombic-Ti$ _2$ AlNb intermetallic phase (O-phase) are promising materials for high-temperature applications in jet engines, given that they can potentially replace Ni-based superalloys in some operating regions of the engines. However, the O-phase is prone to lattice disordering at high temperatures, primarily via anti-site defect formation across the Ti and Nb sites, which can reduce the material’s creep resistance and high-temperature tensile properties, necessitating the need to identify strategies to mitigate the disorder. Here, we focus on identifying suitable alloying additions to suppress the disordering of the O-phase using density functional theory and nudged elastic band calculations. Specifically, we consider six different alloying additions, namely, V, Cr, Fe, Mo, Ta, and W, and examine their role in the thermodynamics of anti-site formation and the kinetics of atomic diffusion. Upon verifying the ground state structure and formation energy of Ti$ _2$ AlNb, we observe the proclivity of all alloying elements (except V) to occupy the Nb site in the O-phase structure. Subsequently, we find that none of the alloying additions can effectively suppress anti-site formation in Ti$ _2$ AlNb, highlighting the unfavourable thermodynamics. However, we find that Mo and W additions to Ti$ _2$ AlNb can kinetically suppress the disorder by reducing the diffusivities of Ti and Nb, by $ \approx$ 4$ \times$ and 8$ \times$ compared to the pristine O-phase, respectively, at an operating temperature of 823 K. Thus, Mo and W additions represent a promising strategy to improve the creep resistance of Ti$ _2$ AlNb-based alloys.
Materials Science (cond-mat.mtrl-sci)
Vanadium-doped HfO$_2$, multiferroic uncompromised
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Vincenzo Fiorentini, Paola Alippi, Gianaurelio Cuniberti
Ab initio density-functional calculations show that orthorhombic Pca21 hafnia HfO2 mixed with vanadium at low concentration is a ferroelectric and ferromagnetic insulator. The multiorbital degeneracy of singly-occupied V states in the nominally 4+ ionic state is broken by magnetism, reduced symmetry, and local distortion, causing a single one-electron majority state per V atom to be occupied. A gap of order 1 eV thus survives at all V concentrations, and intrinsic polarization is preserved, at the level of two-thirds the hafnia value. Ferromagnetic magnetization is found to increase linearly with V content, with values of 30-40 emu/cm3 at concentrations near the end of the stability range.
Materials Science (cond-mat.mtrl-sci)
10 pages, 10 figures
Wavefunction textures in twisted bilayer graphene from first principles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Albert Zhu, Daniel Bennett, Daniel T. Larson, Mohammed M. Al Ezzi, Efstratios Manousakis, Efthimios Kaxiras
Motivated by recent experiments probing the wavefunctions of magic-angle twisted bilayer graphene (tBLG), we perform large-scale first-principles calculations of tBLG with full atomic relaxation across a wide range of twist angles down to $ 0.99^\circ$ . Focusing on the magic angle, we compute wavefunctions of the low energy bands, resolving atomic-scale details and moiré-scale patterns that form triangular, honeycomb, and Kagome lattices. By tuning the interlayer interactions, we illustrate the formation of the flat bands from isolated monolayers and the emergence of the band inversion and fragile topology at a sufficiently large interaction strength. We identify strong indicators of a new topological phase transition with increasing interlayer interaction strength, achievable with external pressure or a decrease in the twist angle. When this transition occurs, the upper and lower flat bands exchange their wavefunction character, which may explain why superconductivity appears with electron doping below the magic angle. Our study demonstrates the feasibility of using first-principles wavefunctions to help interpret experimental signatures of topological and correlated phases in tBLG.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Numerical and data-driven modeling of spall failure in polycrystalline ductile materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Indrashish Saha, Lori Graham-Brady
Developing materials with tailored mechanical performance requires iteration over a large number of proposed designs. When considering dynamic fracture, experiments at every iteration are usually infeasible. While high-fidelity, physics-based simulations can potentially reduce experimental efforts, they remain computationally expensive. As a faster alternative, key dynamic properties can be predicted directly from microstructural images using deep-learning surrogate models. In this work, the spallation of ductile polycrystals under plate-impact loading at strain rates of O(10^6 s^-1) is considered. A physics-based numerical model that couples crystal plasticity and a cohesive zone model is used to generate data for the surrogate models. Three architectures - 3D U-Net, 3D Fourier Neural Operator (FNO-3D), and U-FNO were trained on the particle-velocity field data from the numerical model. The generalization of the models was evaluated using microstructures with varying grain sizes and aspect ratios. U-FNO and 3D U-Net performed significantly better than FNO-3D across all datasets. Furthermore, U-FNO and 3D U-Net exhibited comparable accuracy for every metric considered in this study. However, training the U-FNO requires almost twice the computational effort compared to the 3D U-Net, making it a desirable option for a surrogate model.
Materials Science (cond-mat.mtrl-sci)
Enhanced molecular diffusion near a soft fluctuating membrane
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Ali Mohammadi, Zhen Li, Sophie Marbach, Micheline Abbas
Particles diffusing near interfaces face anisotropic resistance to motion due to hydrodynamic interactions. While this has been extensively studied near \textit{hard} interfaces since the works of Lorentz and Brenner, our understanding of diffusion near \textit{soft, thermally fluctuating} interfaces remains limited. Previous studies have predominantly focused on particles much larger than the molecular scale at which thermal fluctuations become important. In this work, we numerically investigate the dynamics of individual solvent molecules near a thermally fluctuating lipid membrane, a canonical soft interface in biology. We observe that diffusive motion of solvent molecules near the fluctuating membrane is slightly enhanced compared to a flat rigid interface and significantly more so than near an undulated rigid interface. This enhancement in diffusive motion of solvent molecules arises from spontaneous momentum exchanges between the moving membrane and adjacent molecules, promoting mixing. Notably, this dispersion effect overcomes geometric trapping that slows diffusion near the rigid undulated interface. Our analysis reveals that the momentum transfer near the fluctuating membrane is so efficient that it resembles an effective slip boundary condition over a length scale equal to the fluctuation height. These molecular-scale mechanisms differ from those of larger particles, where hydrodynamic memory and elasticity effects can be at play as they relax over timescales comparable to significant diffusive motion. Our findings advance understanding of enhanced diffusive motion and promoted mixing near soft fluctuating membranes involved in diverse biological processes and soft-matter technologies containing natural and model cell membranes.
Soft Condensed Matter (cond-mat.soft)
Entropy production and statistical relaxation of dipolar bosons and fermions in interaction quench dynamics
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Barnali Chakrabarti, N D Chavda, F.V. Prudente
We study the out-of-equilibrium dynamics of dipolar bosons and fermions after a sudden change in the interaction strength from zero to a finite repulsive value. We simulate the interaction quench on the initial state which is the ground state of harmonic potential with noninteracting bosons and fermions. We solve the time-dependent many-boson Schrödinger equation exactly using numerical methods. To understand the many-body dynamics we analyze several measures of many-body information entropy, monitoring their time evolution and assessing their dependence on interaction strength. We establish that for weak interaction quench the dynamics is statistics independent, both dipolar bosons and fermions do not relax. Whereas it is significantly different for dipolar bosons from that of dipolar fermions in the stronger interaction quench. When dipolar bosons exhibit concurrent signature of relaxation in all entropy measures, dipolar fermions fail to relax. For dipolar bosons and for larger interaction quench, the many-body information entropy measures dynamically approach the value predicted for the Gaussian orthogonal ensemble of random matrices, implying statistical relaxation. The relaxation time is uniquely determined when the orbital fragmentation exhibits a $ 1/M$ population in each orbital ($ M$ is the number of orbitals) and all entropy measures saturate to the maximum entropy values. The relaxation time also becomes independent of the strength of dipolar interaction. Whereas, for the same quench protocol, dipolar fermions exhibit modulated oscillations in all entropy dynamics. Our study is also complemented by the measures of delocalization in Hilbert space, clearly establishing the onset of chaos for strongly interacting dipolar bosons. It highlights the importance of many-body effects with a possible exploration in quantum simulation with ultracold atoms.
Quantum Gases (cond-mat.quant-gas)
arXiv admin note: text overlap with arXiv:2405.14928
Thermodynamic bounds and symmetries in first-passage problems of fluctuating currents
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
We develop a method for deriving thermodynamic bounds for first-passage problems of currents with two boundaries. Using this method, we extend some results on first-passage times of fluctuating currents. Notably, we derive a thermodynamic bound on the rate of dissipation of a Markov process in terms of the splitting probabilities and the first-passage time statistics of a fluctuating current, which is a refinement of a previously derived inequality. We also show that the concept of effective affinity, originally developed for continuous-time Markov chains, naturally extends to discrete-time Markov chains. Furthermore, we analyse symmetries in first-passage problems of fluctuating currents with two boundaries. We show that optimal currents – those for which the effective affinity fully accounts for the dissipation – satisfy a symmetry property: the current’s average speed to reach the positive threshold equals the current’s speed to reach the negative threshold. The developed approach uses a coarse-graining procedure for the average entropy production at random times and utilises martingale methods to perform time-reversal of first-passage quantities.
Statistical Mechanics (cond-mat.stat-mech)
39 pages, 7 figures
Kappa distributions in the language of superstatistics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Sergio Davis, Biswajit Bora, Cristian Pavez, Leopoldo Soto
The kappa distribution of velocities appears routinely in the study of collisionless plasmas present in Earth’s magnetosphere, the solar wind among other contexts where particles are unable to reach thermal equilibrium. Originally justified through the use of Tsallis’ non-extensive statistics, nowadays there are alternative frameworks that provide insight into these distributions, such as superstatistics. In this work we review the derivation of the multi-particle and single-particle kappa distributions for collisionless plasmas within the framework of superstatistics, as an alternative to the use of non-extensive statistics. We also show the utility of the superstatistical framework in the computation of expectation values under kappa distributions. Some consequences of the superstatistical formalism regarding correlations, temperature and entropy of kappa-distributed plasmas are also discussed.
Statistical Mechanics (cond-mat.stat-mech), Plasma Physics (physics.plasm-ph)
Direct signatures of Anderson orthogonality catastrophe in nonequilibrium quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Sarath Sankar, Joshua Folk, Yigal Meir, Eran Sela
We propose schemes for unambiguous direct observation of Anderson orthogonality catastrophe (AOC) effects in a quantum dot coupled to a charge detector, and to estimate the strength of the AOC exponent $ \alpha$ . We show that certain easy-to-measure observables have a robust dependence on $ \alpha$ in the non-equilibrium regimes of source-drain voltage bias or thermal imbalance. Our results are obtained using a rate equation formalism in which the AOC effects on tunnel rates are incorporated in an exact manner.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Topological defects govern plasticity and shear band formation in two-dimensional amorphous solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Xin Wang, Jin Shang, Yujie Wang, Jie Zhang, Matteo Baggioli
Understanding the fundamental mechanisms behind plastic instabilities and shear band formation in amorphous media under applied deformation remains a long-standing challenge. Leveraging on the mathematical concept of topology, we revisit this problem using two-dimensional experimental amorphous granular packings subjected to pure shear. We demonstrate that topological defects (TDs) in the displacement vector field act as carriers of plasticity, enabling the prediction of both the onset of plastic flow and the global mechanical response of the system. At the microscopic level, we show that these TDs are responsible for the dynamical breakdown of local orientational order, thereby linking topological excitations to short-range structural changes. Finally, we establish that the spatial localization and cooperative alignment of TDs underlie the formation of macroscopic shear bands, which drive plastic flow under large shear loads. This process is mediated by the quasi-periodic annihilation of large defect clusters and their geometric transformation from an approximately isotropic to a strongly anisotropic shape. Our results provide a unified framework for understanding plastic deformation and shear band formation in two-dimensional amorphous systems by connecting topology, short-range order, and mechanical response.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
v1: comments welcome
Domain-wall melting and entanglement in free-fermion chains with a band structure
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
We study the melting of a domain wall in free-fermion chains, where the periodic variation of the hopping amplitudes gives rise to a band structure. It is shown that the entanglement grows logarithmically in time, and the prefactor is proportional to the number of filled bands in the initial state. For a dimerized chain the particle density and current are found to have the same expressions as in the homogeneous case, up to a rescaling of the velocity. The universal contribution to the entropy profile is then doubled, while the non-universal part can be extracted numerically from block-Toeplitz matrices.
Statistical Mechanics (cond-mat.stat-mech), Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
23 pages, 9 figures
Implantation studies of low-energy positive muons in niobium thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Ryan M. L. McFadden, Andreas Suter, Leon Ruf, Angelo Di Bernardo, Arnold M. Müller, Thomas Prokscha, Zaher Salman, Tobias Junginger
Here we study the range of keV positive muons $ \mu^+$ implanted in Nb$ _2$ O$ _5$ ($ x$ nm)/Nb($ y$ nm)/SiO$ 2$ (300 nm)/Si [$ x$ = 3.6 nm, 3.3 nm; $ y$ = 42.0 nm, 60.1 nm] thin films using low-energy muon spin spectroscopy (LE-$ \mu$ SR). At implantation energies 1.3 keV $ \leq E \leq$ 23.3 keV, we compare the measured diamagnetic $ \mu^+$ signal fraction $ f{\mathrm{dia.}}$ against predictions derived from implantation profile simulations using the this http URL Monte Carlo code. Treating the implanted $ \mu^+$ as light protons, we find that simulations making use of updated stopping cross section data are in good agreement with the LE-$ \mu$ SR measurements, in contrast to parameterizations found in earlier tabulations. Implications for other studies relying on accurate $ \mu^+$ stopping information are discussed.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
13 pages, 11 figures
Short-Range Ordering and Lattice Distortions in Entropy-Stabilized Oxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Bo Jiang, De-Ye Lin, Gerald R. Bejger, Stephen C. Purdy, Yuanpeng Zhang, Xin Wang, Jon-Paul Maria, Christina M. Rost, Katharine Page
Entropy-stabilized oxides (ESOs), driven by high configurational entropy, have gained phenomenological research interest due to their potential for tailoring structure property relationships. However, the chemical short range ordering (SRO) and its interplay with local lattice distortion (LD) remain to be explored, although they could diminish the configurational entropy and potentially impact structure property relationships. A combination of experimental and theoretical approaches are employed to investigate the SRO and LD in the prototype ESO, Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O, generally referred to as J14. We demonstrate that the efficiency and accuracy of density functional theory (DFT) relaxed special quasirandom structures (SQS) enhances the analysis of the local structure of J14, unveiling the unique local cationic environments. Importantly, this joint experimental and computational approach sheds light on the understanding of local structure and structure property relationships in J14, demonstrating the necessity for further research into other high entropy and compositionally complex materials.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
27pages,5 figures
Thermodynamics of analogue black holes in a non-Hermitian tight-binding model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
D.F. Munoz-Arboleda, M. Stålhammar, C. Morais Smith
We present a non-Hermitian model with gain/loss and non-reciprocal next-nearest-neighbor hopping that emulates black-hole physics. The model describes a one-dimensional lattice with a smooth connection between regions with distinct hopping parameters. By mapping the system to an effective Schwarzschild metric in the Painlevé-Gullstrand coordinates, we find that the interface is analogue to a black-hole event horizon. We obtain emission rates for particles and antiparticles, the Hawking temperature, the Bekenstein-Hawking entropy, and the mass of the analogue black hole as a function of the interface sharpness and the system parameters. An experimental realization of the theoretical model is proposed, thus opening the way to the detection of elusive black-hole features.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Relativity and Quantum Cosmology (gr-qc), High Energy Physics - Theory (hep-th)
Main text 5 pages, Appendix 3 pages, 4 figures
Multicolor groups for molecules and solids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Hai-Yang Ma, Shihao Zhang, Hu Xu, Shengbai Zhang, Jin-Feng Jia
Just like we classify lions and tigers into the same panthera, but into different species, we can classify molecules and solids by their spatial and spin space symmetries. In magnetic molecules and solids, local moments of the atoms can be represented by different colors; we can therefore classify these materials by playing with colors. The advantage of the multicolor group scheme is that it unifies the classifications into a single framework through multicolor group theory, including the recently identified altermagnets and $ p$ -wave magnets. In particular, non-magnetic compounds fall into 0-color groups, ferro/ferrimagnets fall into 1-color groups, antiferromagnets, as usual, fall into 2-color groups, and non-collinear magnets fall into the simple and complex multicolor groups. Moreover, confusions brought about by conventional magnetic-group classification can be resolved through this new framework.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
7 pages, 2 figures, 3 tables
High Temperature Superconductivity Dominated by Inner Underdoped CuO$_2$ Planes in Quadruple-Layer Cuprate (Cu,C)Ba$_2$Ca$_3$Cu$4$O${11+δ}$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Xingtian Sun, Suppanut Sangphet, Nan Guo, Yu Fan, Yutong Chen, Minyinan Lei, Xue Ming, Xiyu Zhu, Hai-Hu Wen, Haichao Xu, Rui Peng, Donglai Feng
The superconducting transition temperature ($ T_{\mathrm{c}}$ ) of trilayer or quadruple-layer cuprates typically surpasses that of single-layer or bilayer systems. This observation is often interpreted within the composite picture", where strong proximity effect between inner CuO$ _2$ planes (IPs) and outer CuO$ _2$ planes (OPs) is crucial. Albeit intriguing, a straightforward scrutinization of this composite picture is still lacking. In this study, using angle-resolved photoemission spectroscopy to investigate (Cu,C)Ba$ _2$ Ca$ _3$ Cu$ _4$ O$ _{11+\delta}$ (CuC-1234) with a high $ T_{\mathrm{c}}$ of 110~K, we found that the OPs are not superconducting at the $ T_{\mathrm{c}}$ of the material. Instead, the large pairing strength and phase coherence concurrently emerge at the underdoped IPs, suggesting that the high $ T_{\mathrm{c}}$ is primarily driven by these underdoped IPs. Given that the $ T_{\mathrm{c}}$ of CuC-1234 is comparable to other trilayer or quadruple-layer cuprates, our findings suggest that the conventional composite picture” is not universally required for achieving high $ T_{\mathrm{c}}$ . More importantly, we demonstrate that CuO$ 2$ planes free of apical oxygen can support superconductivity up to 110~K even at a doping level of 0.07 holes per Cu, a level that lies deep in the underdoped regime of single- and bilayer cuprates. These findings provide new insights into the origin of high $ T{\mathrm{c}}$ in multilayer cuprates.
Superconductivity (cond-mat.supr-con)
6 pages, 4 figures
Hyperuniform interfaces in non-equilibrium phase coexistence
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Raphaël Maire, Leonardo Galliano, Andrea Plati, Ludovic Berthier
We show that long-wavelength interfacial fluctuations are strongly suppressed in non-equilibrium phase coexistence between bulk hyperuniform systems. Using simulations of three distinct microscopic models, we demonstrate that hyperuniform interfaces are much smoother than equilibrium ones, with a universal reduction of height fluctuations at large scale. We derive a non-equilibrium interface equation from the field theory of the bulk order parameter, and predict a reduction in height fluctuations, $ S_h(\boldsymbol k)\equiv \langle |h(\boldsymbol k)|^2\rangle\sim |\boldsymbol k|^{-1}$ , in stark contrast to equilibrium capillary wave theory where $ S_h(\boldsymbol k)\sim |\boldsymbol k|^{-2}$ . Our results establish a new universality class for non-equilibrium interfaces, highlighting the fundamental role of suppressed bulk fluctuations in shaping interfacial dynamics far from equilibrium.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
Rigid Spheres Rising at Constant Speed Through Collections of Hydrogels
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Tom Mullin, Tommaso Pettinari, Joshua A. Dijksman
We present the results of an experimental investigation into buoyant rigid spheres rising through concentrated collections of hydrated hydrogel particles. The volume fraction of particles is such that the mechanical properties of the material are intermediate between a very viscous fluid and a soft solid. Despite the non-Newtonian character of these hydrogels, we find that when the surface of the material is free, an immersed buoyant sphere rises with a constant speed. The effects of the motion in the surrounding material are observed to be highly localized around the sphere. When the mass of the sphere is varied, its terminal velocity is observed to depend exponentially on the buoyancy. Qualitatively distinct behavior is found when a lid is present on the surface of the material, and in this case, a sublinear time dependence of the displacement is found. Linear motion of the sphere is accompanied by flow at the surface of the material whereas fluid movement is suppressed when a lid is applied. Other boundary condition variations are consistent with the perspective that constant speed motion is induced by the presence of a free boundary.
Soft Condensed Matter (cond-mat.soft)
17 pages, 14 figures
Polariton transport in 2D semiconductors: Phonon-mediated transitions between ballistic, superdiffusive and exciton-limited regimes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Jamie M. Fitzgerald, Roberto Rosati, Ermin Malic
Exciton transport in 2D semiconductors holds promise for room-temperature, ultra-compact optoelectronic devices, but it is limited by short propagation distances. Hybridization of excitons with cavity photons to form exciton-polaritons can enhance the propagation by orders of magnitude, enabling a coherent, ballistic transport. However, a microscopic understanding of the role of phonons is still lacking, particularly regarding their influence on the crossover from the ballistic to the diffusive polariton transport regime. Here, we investigate the spatiotemporal polariton dynamics in \ce{MoSe2} monolayers at moderate to high temperatures, explicitly including the phonon-mediated coupling to the intervalley exciton reservoir. We identify three distinct transport regimes: (i) an initial sub-ps ballistic-like regime characterized by a phonon-induced velocity renormalization, (ii) a transient, few-ps superdiffusive regime characterized by strongly enhanced diffusion, and (iii) a slower, exciton-limited diffusion following thermalization. The gained microscopic insights will trigger and guide future experimental studies on the phonon-mediated polariton transport in atomically thin semiconductors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Ferroelectrically Switchable Half-Quantized Hall Effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
M. U. Muzaffar, Kai-Zhi Bai, Wei Qin, Guohua Cao, Bo Fu, Ping Cui, Shun-Qing Shen, Zhenyu Zhang
Integrating ferroelectricity, antiferromagnetism, and topological quantum transport within a single material is rare, but crucial for developing next-generation quantum devices. Here, we propose a multiferroic heterostructure consisting of an antiferromagnetic MnBi$ _2$ Te$ _4$ bilayer and an Sb$ _2$ Te$ _3$ film is able to harbor the half-quantized Hall (HQH) effect with a ferroelectrically switchable Hall conductivity of $ e^2/2h$ . We first show that, in the energetically stable configuration, the antiferromagnetic MnBi$ _2$ Te$ _4$ bilayer opens a gap in the top surface bands of Sb$ _2$ Te$ _3$ through proximity effect, while its bottom surface bands remain gapless; consequently, HQH conductivity of $ e^2/2h$ can be sustained clockwise or counterclockwise depending on antiferromagnetic configuration of the MnBi$ _2$ Te$ _4$ . Remarkably, when applying interlayer sliding within the MnBi$ _2$ Te$ _4$ bilayer, its electric polarization direction associated with parity-time reversal symmetry breaking is reversed, accompanied by a reversal of the HQH conductivity. The proposed approach offers a powerful route to control topological quantum transport in antiferromagnetic materials by ferroelectricity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
16 pages, 4 figures
Nano Lett. 25, 7361-7367 (2025)
On-Device Control of Electronic Friction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Zhaokuan Yu, Jinbo Bian, Jin Wang, Zonghuiyi Jiang, Linxin Zhai, Xin Lu, Xiaofei Liu, Quanshui Zheng, Zhiping Xu
Friction causes mechanical energy dissipation and material degradation in machinery and devices. While phononic friction is well understood via anharmonic lattice dynamics, the physics of electronic friction remains unclear due to challenges in separating electronic degrees of freedom from phononic ones in experiments and analyzing the non-equilibrium interactions between ionic movement and electronic dynamics in theory. To tackle this problem, we construct a sliding device featuring 2D crystalline interfaces that possess ultra-smooth and minimally interacting surfaces, achieving the state of structural superlubricity with no wear and minimal friction. Using electrical and mechanical controls, we tuned the nature of interfacial electronic coupling and charge densities in materials in an on-device setting, which allows us to disentangle the electron and phonon contributions to friction. Our experimental data and theoretical analysis supported by first-principles calculations demonstrate that electronic friction can well surpass phononic contributions and dominate energy dissipation at structural superlubricity contacts. These findings offer fresh insights into the mechanism of electronic friction and promising opportunities for friction control in device applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Prediction of High-Temperature Half Quantum Anomalous Hall Effect in a Semi-magnetic Topological Insulator of MnBi$_2$Te$_4$/Sb$_2$Te$_3$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
M. U. Muzaffar, Kai-Zhi Bai, Wei Qin, Guohua Cao, Yutong Yang, Shunhong Zhang, Ping Cui, Shun-Qing Shen, Zhenyu Zhang
The classic Thouless-Kohmoto-Nightingale-Nijs theorem dictates that a single electron band of a lattice can only harbor an integer quantum Hall conductance as a multiple of e^2/2h, while recent studies have pointed to the emergence of half quantum anomalous Hall (HQAH) effect, though the underlying microscopic mechanisms remain controversial. Here we propose an ideal platform of MnBi$ _2$ Te$ _4$ /Sb$ _2$ Te$ _3$ that allows not only to realize the HQAH effect at much higher temperatures, but also to critically assess the different contributions of the gapped and gapless Dirac bands. We first show that the top surface bands of the Sb$ _2$ Te$ _3$ film become gapped, while the bottom surface bands remain gapless due to proximity coupling with the MnBi$ _2$ Te$ _4$ overlayer. Next we show that such a semi-magnetic topological insulator harbors the HQAH effect at ~20 K, with Cr doping enhancing it to as high as 67 K, driven by large magnetic anisotropy and strong magnetic coupling constants that raise the Curie temperature. Our detailed Berry curvature analysis further helps to reveal that, whereas the gapped surface bands can contribute to the Hall conductance when the chemical potential is tuned to overlap with the bands, these bands have no net contribution when the chemical potential is in the gapped region, leaving the gapless bands to be the sole contributor to the HQAH conductance. Counterintuitively, the part of the gapless bands within the gapped region of the top surface bands have no net contribution, thereby ensuring the plateau nature of the Hall conductance.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
17 pages, 5 figures
Non-reciprocal spin-wave excitations in Rashba-Hubbard ferromagnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Aastha Jain, Dheeraj Kumar Singh
We explore the nonreciprocity of spin-wave excitations in the Rashba-Hubbard ferromagnet within the random-phase approximation. We find that the non-reciprocal behavior arises only when the magnetic moments are aligned in-plane and not out-of-plane. Furthermore, the spin-wave excitations exhibit non-reciprocal behavior in a direction in the momentum space reciprocal to an in-plane direction perpendicular to the orientation of the magnetic moments. In that case, the first dominating term in the low-energy dispersion is linear. However, if the magnetic moments are out-of-plane, then the first dominant term is quadratic instead. The low-energy non-quadratic behavior is examined in the intermediate-to-strong coupling regime for various strengths of Rashba spin-orbit coupling.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 7 figures
Transient segregation of bi-disperse granular mixtures in a periodic chute flow
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Soniya Kumawat, Vishnu Kumar Sahu, Anurag Tripathi
Transient size segregation of a bi-disperse granular mixture flowing over a periodic chute is studied using the Discrete Element Method and continuum simulations. A recently developed particle force-based size segregation model is used to predict the time-dependent flow properties of binary mixtures starting from rest. A two-way coupled continuum model that solves the momentum balance and convection-diffusion equations by incorporating the mixture segregation model along with the generalized inertial number-based rheological model is developed for predicting the evolution of segregation. The predicted concentration profiles and other flow properties of the mixture are found to be in good agreement with the DEM data for a variety of compositions. The evolution of the centre of mass of the two species with time is also very well captured for different initial configurations and size ratios using the particle force-based segregation model.
Soft Condensed Matter (cond-mat.soft)
Specific heat and density anomalies in the Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
M. A. Habitzreuter, Willdauany C. de Freitas Silva, Eduardo O. Rizzatti, Thereza Paiva, Marcia C. Barbosa
Understanding thermal properties of materials is fundamental to technological applications and to discover new phenomena. In particular, advances of experimental techniques such as cold-atoms measurements allow the simulation of paradigmatic Hamiltonians with great control over model parameters, such as the Fermi-Hubbard model. One aspect of this model which is not much explored is the behavior of the specific heat as function of density. In this work, we perform Determinant Quantum Monte Carlo simulations of the Hubbard model to analyze the specific heat as the filling, interaction and temperature of the system is changed. We found that, with strong correlations, the specific heat presents a three-maxima structure as a function of filling, with local minima between them. This effect can be explained by a decomposition of kinetic and potential contributions to the specific heat. Moreover, by analyzing the kinetic contribution in momentum space we show that, connected to this specific heat behavior, there is a density anomaly detected through the thermal expansion coefficient. These momentum-space quantities are accessible using cold-atoms experiments. Finally, we map the location of these phenomena and connect the thermal expansion anomaly with the well-known Seebeck coefficient change of sign. Our results provide a new perspective to analyze this change of sign. Moreover, our specific heat results demonstrate interesting phenomena away from the commonly studied half-filling regime.
Strongly Correlated Electrons (cond-mat.str-el)
Microscopy of Ultracold Fermions in Optical Lattices
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Waseem S. Bakr, Zengli Ba, Max L. Prichard
These lecture notes review recent progress in studying the Fermi-Hubbard model using ultracold gases in optical lattices. We focus on results from quantum gas microscope experiments that have allowed site-resolved measurements of charge and spin correlations in half-filled and doped Hubbard systems, as well as direct imaging of various types of polaronic quasiparticles. We also review experiments exploring dynamical properties of the Hubbard model through transport and spectroscopy. Moving beyond the plain-vanilla square-lattice Hubbard model, we present more recent work exploring Hubbard systems with novel lattice geometries and long-range interactions that stabilize new phases. Finally, we discuss the realization of entropy distribution protocols to cool these systems to ultralow temperatures where comparison to unbiased numerics is no longer possible.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
Submitted to appear in the Proceedings of the Course 214 “Quantum Computers and Simulators with Atoms” of the International School of Physics “Enrico Fermi” (Varenna, July 2024). 47 pages, 24 figures
TopoMAS: Large Language Model Driven Topological Materials Multiagent System
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Baohua Zhang, Xin Li, Huangchao Xu, Zhong Jin, Quansheng Wu, Ce Li
Topological materials occupy a frontier in condensed-matter physics thanks to their remarkable electronic and quantum properties, yet their cross-scale design remains bottlenecked by inefficient discovery workflows. Here, we introduce TopoMAS (Topological materials Multi-Agent System), an interactive human-AI framework that seamlessly orchestrates the entire materials-discovery pipeline: from user-defined queries and multi-source data retrieval, through theoretical inference and crystal-structure generation, to first-principles validation. Crucially, TopoMAS closes the loop by autonomously integrating computational outcomes into a dynamic knowledge graph, enabling continuous knowledge refinement. In collaboration with human experts, it has already guided the identification of novel topological phases SrSbO3, confirmed by first-principles calculations. Comprehensive benchmarks demonstrate robust adaptability across base Large Language Model, with the lightweight Qwen2.5-72B model achieving 94.55% accuracy while consuming only 74.3-78.4% of tokens required by Qwen3-235B and 83.0% of DeepSeek-V3’s usage–delivering responses twice as fast as Qwen3-235B. This efficiency establishes TopoMAS as an accelerator for computation-driven discovery pipelines. By harmonizing rational agent orchestration with a self-evolving knowledge graph, our framework not only delivers immediate advances in topological materials but also establishes a transferable, extensible paradigm for materials-science domain.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
13 pages,7 figures,3 tables
Characterization of fractional Chern insulator quasiparticles in moiré transition metal dichalcogenides
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Zhao Liu, Bohao Li, Fengcheng Wu
We provide a detailed study of Abelian quasiparticles of valley polarized fractional Chern insulators (FCIs) residing in the top valence band of twisted bilayer MoTe$ _2$ (tMoTe$ _2$ ) at hole filling $ \nu_h=2/3$ . We construct a tight-binding model of delocalized quasiparticles to capture the energy dispersion of a single quasiparticle. We then localize quasiparticles by short-range delta impurity potentials. Unlike the fractional quantum Hall (FQH) counterpart in the lowest Landau level (LLL), the density profile around the localized FCI quasiparticle in tMoTe$ _2$ depends on the location of the impurity potential and loses the continuous rotation invariance. The FCI quasiparticle localized at moiré lattice center closely follows the anyon Wannier state of the tight-binding model of the mobile quasiparticle. Despite of the difference in density profiles, we find that the excess charge around the impurity potential for the $ \nu_h=2/3$ FCIs in tMoTe$ _2$ is still similar to that of the $ \nu=2/3$ FQH state in the LLL if an effective magnetic length on the moiré lattice is chosen as the length unit, which allows a rough estimation of the spatial extent of the FCI quasiparticle. Far away from the impurity potential, this excess charge has the tendency to reach $ e/3$ , as expected for the Laughlin quasiparticle. The braiding phase of two FCI quasiparticles in tMoTe$ _2$ also agrees with the theoretical prediction of fractional statistics. Based on the nearly ideal quantum geometry of the top valence band of tMoTe$ _2$ , we propose a trial wave function for localized FCI quasiparticles, which reproduces the key feature of the density profile around a quasiparticle. We also discuss the effect of band mixing on FCI quasiparticles in tMoTe$ _2$ .
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 13 figures
Observation of Momentum-Band Topology in PT-Symmetric acoustic Floquet Lattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Shuaishuai Tong, Qicheng Zhang, Gaohan Li, Kun Zhang, Chun Xie, Chunyin Qiu
Momentum-band topology, which transcends conventional topological band theory, unlocks new topological phases that host fascinating temporal interface states. However, direct bulk experimental evidence of such emerging band topology is still lacking due to the great challenges in resolving eigenstates and topological invariants of time-varying systems. Here, we present a comprehensive study on the momentum-band topology in a PT-symmetric Floquet lattice, where the drive-induced momentum gap can be characterized by a quantized Berry phase in the energy Brillouin zone. Experimentally, we synthesize the Floquet lattice model using an acoustic cavity-tube structure coupled to custom-designed external circuits. By reconstructing the effective Hamiltonian, we extract the system’s eigenstates and provide the first bulk evidence of momentum-band topology from the perspectives of band inversion and topological invariants. This is accompanied by an unambiguous observation of time-localized interface states in real physical time, thereby providing the boundary signature of the bulk topology. Our work paves the way for further experimental studies on the burgeoning momentum-gap physics.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
7 pages, 5 figures
Time-Dependent Oxidative Degradation of WSe2 Nanosheets and Its Influence on HER Catalysis
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Panwad Chavalekvirat, Wisit Hirunpinyopas, Pawin Iamprasertkun
The selection of an appropriate solvent has long been a critical factor in the liquid phase exfoliation (LPE) of two-dimensional transition metal dichalcogenide (2D TMD) nanosheets. N-methyl-2-pyrrolidone (NMP) remains one of the most commonly used solvents due to its favourable surface tension compatibility, particularly with tungsten diselenide (WSe2), which facilitates a relatively high yield of exfoliated nanosheets. However, prolonged exposure of the nanosheets to NMP promotes oxidation, consequently diminishing their hydrogen evolution reaction (HER) activity. In contrast, a more environmentally friendly solvent system, consisting of isopropyl alcohol (IPA) and deionised water (DI), induces significantly less oxidation and results in enhanced HER performance. Notably, this green solvent system achieves the lowest overpotential of 0.209 V vs RHE after 24 hours of chronoamperometry.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
32 pages, 11 figures
Absence of higher than 6-fold coordination in glassy $GeO_{2}$ up to 158 GPa revealed by X-ray absorption spectroscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
João Elias F. S. Rodrigues, Angelika D. Rosa, Emin Mijit, Tetsuo Irifune, Gaston Garbarino, Olivier Mathon, Raffaella Torchio, Max Wilke
Simple binary oxide glasses can exhibit a compression behavior distinct from that of their crystalline counterparts. In this study, we employed high-pressure X-ray absorption spectroscopy coupled to the diamond anvil cell to investigate in detail local structural changes around Ge in glassy $ GeO_{2}$ up to 158 GPa. We conducted four independent runs, both with and without pressure-transmitting media. Up to 30 GPa, we observed no significant influence of the pressure medium on the pressure dependence of the $ Ge-O$ bond length ($ <R_{Ge-O}>$ ). Between 10 and 30 GPa, the evolution of $ <R_{Ge-O}>$ shows substantial variability across our experiments and previous works. The measured values lie close to those reported for crystalline polymorphs, including the rutile- and $ CaCl_{2}$ -type phase of $ GeO_{2}$ . This finding suggests that the amorphous structure possesses considerable flexibility to transition among different atomic configurations. From 30 GPa to 158 GPa, our results for both $ <R_{Ge-O}>$ and the non-bonded cation-cation distance $ <R_{Ge…Ge}>$ demonstrate that edge-sharing octahedra remain the main structural motives in glassy $ GeO_{2}$ . Up to 100 GPa, compaction proceeds primarily via distortions of octahedral $ O-Ge-O$ bond angles accompanied by octahedral bond shortening. Above 100 GPa, octahedral distortion becomes the prevailing mechanism. Compared to its crystalline analogues ($ \alpha-PbO_{2}$ and pyrite-like phase), glassy $ GeO_{2}$ exhibits a slightly less efficient compaction mechanism, likely due to kinetic constraints that inhibit reconstructive lattice rearrangements.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
32 pages, 11 figures, 2 tables
Microscopic Origins of Conformable Dynamics: From Disorder to Deformation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Conformable derivatives have attracted increasing interest for bridging classical and fractional calculus while retaining analytical tractability. However, their physical foundations remain underexplored. In this work, we provide a systematic derivation of conformable relaxation dynamics from microscopic principles. Starting from a spatially-resolved Ginzburg-Landau framework with quenched disorder and temperature-dependent kinetic coefficients, we demonstrate how spatial heterogeneity and energy barrier distributions give rise to emergent power-law memory kernels. In the adiabatic limit, these kernels reduce to a conformable temporal structure of the form T^{1-\mu},d\psi/dT. The deformation parameter \mu is shown to be connected to experimentally measurable properties such as transport coefficients, disorder statistics, and relaxation time spectra. This formulation also reveals a natural link with nonextensive thermodynamics and Tsallis entropy. By unifying memory effects, anomalous relaxation, and spatial correlations under a coherent physical mechanism, our framework transforms conformable derivatives from heuristic tools into physically grounded operators suitable for modeling complex critical dynamics.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Other Condensed Matter (cond-mat.other), Mathematical Physics (math-ph), Classical Physics (physics.class-ph)
25 pages
Longitudinal magnon transport properties in the easy-axis XXZ Heisenberg ferromagnet on the face-centered cubic lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
We present a detailed investigation of longitudinal magneto-thermal transport in the $ S=1/2$ ferromagnetic XXZ model with easy-axis exchange anisotropy ($ \Delta>1$ ) on a face-centered cubic lattice consisting of four sublattices. We employ linear spin-wave theory and the Kubo formalism to evaluate the longitudinal spin and thermal conductivities, both of which exhibit activated temperature dependence in the low-temperature regime, and to determine their magnetic-field dependence. Our analysis indicates that a magnon gap is crucial for ensuring the convergence of these conductivities. Furthermore, by examining the ratio of thermal conductivity to spin conductivity, we identify an analog of the Wiedemann-Franz law for magnon transport at low temperatures. Finally, we demonstrate that these results can be generalized to systems with arbitrary spin.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 3 figures
Effective behavior of heterogeneous media governed by strain gradient elasticity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Harkirat Singh, Mayank Raj, Kaushik Bhattacharya
Various mechanical phenomena depend on the length scale, and these have inspired a variety of nonlocal and higher gradient continuum theories. Mechanistically, it is believed that the length scale dependence arises due to an interplay between the length scale of heterogeneities in the material, the length scale of the material being probed and the phenomenon under study. In this paper, we seek to understand this interplay in a simple setting by studying the overall behavior of a one-dimensional periodic medium governed by strain gradient elasticity at the microstructural scale. We find that the overall behavior is not described by a strain gradient elasticity. In other words, strain gradient theories are not invariant under averaging at this scale. We also find that the overall behavior may be described by a kernel-based nonlocal elasticity theory, and approximated locally by a fractional strain gradient elasticity. Consequently, one can obtain various scaling laws with exponent between zero (classical elasticity) and one (strain-gradient elasticity). We also learn the overall behavior using a Fourier neural operator.
Materials Science (cond-mat.mtrl-sci)
Phenomenological model of decaying Bose polarons
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Ragheed Alhyder, Georg M. Bruun, Thomas Pohl, Mikhail Lemeshko, Artem G. Volosniev
Cold atom experiments show that a mobile impurity particle immersed in a Bose-Einstein condensate forms a well-defined quasiparticle (Bose polaron) for weak to moderate impurity-boson interaction strengths, whereas a significant line broadening is consistently observed for strong interactions. Motivated by this, we introduce a phenomenological theory based on the assumption that the most relevant states are characterized by the impurity correlated with at most one boson, since they have the largest overlap with the uncorrelated states to which the most common experimental probes couple. These experimentally relevant states can however decay to lower energy states characterised by correlations involving multiple bosons, and we model this using a minimal variational wave function combined with a complex impurity-boson interaction strength. We first motivate this approach by comparing to a more elaborate theory that includes correlations with up to two bosons. Our phenomenological model is shown to recover the main results of two recent experiments probing both the spectral and the non-equilibrium properties of the Bose polaron. Our work offers an intuitive framework for analyzing experimental data and highlights the importance of understanding the complicated problem of the Bose polaron decay in a many-body setting.
Quantum Gases (cond-mat.quant-gas)
Orbital mixing as key ingredient for magnetic order in a van der Waals ferromagnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Alessandro De Vita, Srdjan Stavrić, Roberto Sant, Nicholas B. Brookes, Ivana Vobornik, Giancarlo Panaccione, Silvia Picozzi, Martin Wolf, Laurenz Rettig, Ralph Ernstorfer, Tommaso Pincelli
Recent years have seen a vast increase in research onto van der Waals magnetic materials, due to the richness of many-body effects and the versatility for next-generation technologies. In many of these systems, magnetism is introduced via light 3\textit{d}-transition metal elements, combined with chalcogenides or halogens. Despite the high technological promise in the field of spintronics, the connection between the \textit{d}-wave orbital configuration and the occurrence of low-dimensional magnetic order is currently unclear. To solve this issue, here we address the prototypical two-dimensional ferromagnet CrI\textsubscript{3}, via complementary absorption and photoemission spectroscopies, and density functional theory calculations. We reveal the electronic structure and orbital character of bulk CrI\textsubscript{3} in the paramagnetic and ferromagnetic phases, describing the couplings underpinning its energy diagram, and demonstrating that the mechanism of stabilization of ferromagnetism in this material is attributable to the orbital mixing between I \textit{p} and Cr \textit{e\textsubscript{g}} states. These findings reveal the microscopic connection between orbital and spin degrees of freedom, providing fundamental insights that can be readily generalized to many other low-dimensional magnetic materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Modeling of a twisted-Kagome HoAgGe spin ice using Reduced-Configuration-Space Search and Density Functional Theory
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Gunnar F. Schwertfeger, Po-Hao Chang, Predrag Nikolic, Igor I. Mazin
The Kagome lattice is a 2D network of corner sharing triangles found in several rare earth materials resulting in a complicated and often frustrated magnetic system. In the last decades, modifications of the motif, such as breathing Kagome, asymmetric Kagome, and twisted Kagome were brought into the limelight. In particular, the latter has lower symmetry than the original Kagome and thus allows implementations of an “Ising-local” Hamiltonian, leading to a 2D spin ice. One such material implementation, HoAgGe, was recently reported to have an exceptionally rich phase diagram and is a strongly frustrated 2D spin-ice material with a twisted-Kagome geometry. In the presence of an external magnetic field the compound exhibits step-like magnetization plateaus at simple fractions of the saturation magnetization. It is believed that this phenomenon results from strong single-site anisotropy, which in HoAgGe was found to be in-plane and along a high-symmetry direction. Previous Monte Carlo simulations with empirical exchange parameters explain some, but not all experimental observations. In this work we present (a) first-principle calculations of the crucial model parameters and (b) direct energy minimization via a Reduced-Configuration-Space search, as well as Monte-Carlo simulations of the field-dependent phase diagram. We find that for HoAgGe the calculated exchange parameters are very different from the earlier suggested empirical ones, and describe the phase diagram much more accurately. This is likely because the first-principles parameters are, in addition to geometrically, also parametrically frustrated.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Electrons in quantum dots on helium: from charge qubits to synthetic color centers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Electrons trapped above the surface of helium provide a means to study many-body physics free from the randomness that comes from defects in other condensed-matter systems. Localizing an electron in an electrostatic quantum dot makes its energy spectrum discrete, with controlled level spacing. The lowest two states can act as charge qubit states. In this paper, we study how the coupling to the quantum field of capillary waves on helium – ripplons – affects electron dynamics. As we show, the coupling can be strong. This bounds the parameter range where electron-based charge qubits can be implemented. The constraint is different from the conventional relaxation time constraint. The electron-ripplon system in a dot is similar to a color center formed by an electron defect coupled to phonons in a solid. In contrast to solids, the coupling in the electron on helium system can be varied from strong to weak. This enables a qualitatively new approach to studying color center physics. We analyze the spectroscopy of the pertinent synthetic color centers in a broad range of the coupling strength
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Gate Voltage-Controlled Magnetic Anisotropy Effect on Pt-Porphyrin functionalized single-layer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Ambika Shanker Shukla, Abhishek Erram, Heston Mendonca, Deepak Kumar, Akanksha Chouhan, Rachit Pandey, Ashwin A. Tulapurkar
This report presents for the first time the investigation of a novel class of functionalized graphene showing a large Voltage Controlled Magnetic Anisotropy Effect (VCMA) with enhanced Spin-Orbit Coupling (SOC), which holds promise for applications in Spintronics devices aimed at ultra-low power memory and logic functionalities. Our study was conducted at the interface of Single Layer chemical vapor deposition (CVD) method-grown graphene (SLG hereafter) grafted with Platinum(II) 5,10,15,30-(tetraphenyl) porphyrin (Pt-Porphyrin hereafter) and NiFe(Py hereafter). The stability of Pt-Porphyrin functionalized SLG at room temperature granted the execution of voltage-dependent Spin Torque Ferromagnetic resonance (ST-FMR) measurements. A substantial VCMA coefficient of 375.6 (fJV-1m-1) was determined at the interface, and the Spin torque efficiency ({\theta}sh) was improved by an order of one in functionalized graphene to compare with pristine SLG
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Thermal relaxation and the complete set of second order transport coefficients for the unitary Fermi gas from kinetic theory
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Christian Hall, Thomas Schaefer
We compute the complete set of second order transport coefficients of the unitary Fermi gas, a dilute gas of spin 1/2 particles interacting via an $ s$ -wave interaction tuned to infinite scattering length. The calculation is based on kinetic theory and the Chapman-Enskog method at second order in the Knudsen expansion. We take into account the exact two-body collision integral. We extend previous results on second order coefficients related to shear stress by including terms related to heat flow and gradients of the fugacity. We confirm that the thermal relaxation time is given by the simple estimate $ \tau_\kappa = \kappa m/(c_PT)$ even if the full collision kernel is taken into account. Here, $ \kappa$ is the thermal conductivity, $ m$ is the mass of the particles, $ c_P$ is the specific heat at constant pressure, and $ T$ is the temperature.
Quantum Gases (cond-mat.quant-gas)
30 pages, no figures
Unusual electronic structure in underdoped cuprate superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Xiang Li, Minghuan Zeng, Huaiming Guo, Shiping Feng
The underdoped cuprate superconductors are characterized by the opening of the pseudogap, while such an aspect of the pseudogap effect should be reflected in the low-energy electronic structure (LEES). Here the effect of the pseudogap on LEES in the underdoped cuprate superconductors is investigated within the kinetic-energy-driven superconductivity. The strong coupling of the electrons with the spin excitation induces the pseudogap-state in the particle-hole channel and superconducting (SC) state in the particle-particle channel, where the pseudogap and SC gap respectively originate from the electron normal and anomalous self-energies, and are evaluated by taking into account the vertex correction. As a natural consequence of the interplay between the pseudogap-state and SC-state, the SC transition temperature Tc exhibits a dome-like shape of the doping dependence, however, in a striking contrast to Tc in the underdoped regime, the pseudogap crossover temperature T\ast is much higher than Tc in the underdoped regime, and then it decreases with the increase of doping, eventually disappearing together with Tc at the end of the SC dome. Concomitantly, the spectral weight on the electron Fermi surface (EFS) at around the antinodal region is suppressed strongly by this pseudogap, and then EFS is truncated to form four disconnected Fermi arcs centered around the nodal region with the largest spectral weight located at around the tips of the disconnected Fermi arcs. Moreover, the dip in the peak-dip-hump structure observed in the energy distribution curve and checkerboard charge ordering found in the ARPES autocorrelation are intrinsically connected with the emergence of the pseudogap. The theory therefore indicates that the same spin excitation that governs both the pseudogap-state and SC-state naturally leads to the exotic features of LEES in the underdoped cuprate superconductors.
Superconductivity (cond-mat.supr-con)
21 pages, 8 figures. This paper is invited written for the commemoration volume for Professor Jan Zaanen, and has been accepted for publication in Physica C: Superconductivity and its Applications
Quantum Metric Enhancement and Hierarchical Scaling in One-Dimensional Quasiperiodic Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Jundi Wang, Yuxiao Chen, Huaqing Huang
The quantum metric, a key component of quantum geometry, plays a central role in a wide range of physical phenomena and has been extensively studied in periodic crystals and moiré materials. Here, we systematically investigate quantum geometry in one-dimensional (1D) quasiperiodic systems and uncover novel properties that fundamentally distinguish them from both periodic crystals and disordered media. Our comparative analysis reveals that quasiperiodicity significantly enhances the quantum metric – despite the absence of translational symmetry – due to the presence of critical wavefunctions with long-range spatial correlations. In the Aubry-André-Harper model, we show that the quantum metric serves as a sensitive probe of localization transitions, exhibiting sharp changes at the critical point and distinct behaviors near mobility edges. In the Fibonacci chain, characterized by a singular continuous spectrum, we discover an anomalous enhancement of the quantum metric when the Fermi level lies within the minimal gaps of the fractal energy spectrum. Using a perturbative renormalization group framework, we trace this enhancement to the hierarchical structure of the spectrum and the bonding-antibonding nature of critical states across narrow gaps. Our findings establish a fundamental connection between wavefunction criticality, spectral fractality, and quantum geometry, suggesting quasiperiodic systems as promising platforms for engineering enhanced quantum geometric properties beyond conventional crystalline paradigms.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
18 pages 17 figures. comments are welcome
Thermodynamics of quantum oscillators
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
In this work, we present a compact analytical approximation for the quantum partition function of systems composed of quantum oscillators. The proposed formula is general and applicable to an arbitrary number of oscillators described by a rather general class of potential energy functions (not necessarily polynomials). Starting from the exact path integral expression of the partition function, we introduce a time-dependent Gaussian approximation for the potential contribution and, then, invoke a principle of minimal sensitivity to minimize the error. This leads to a system of coupled nonlinear equations whose solution yields the optimal parameters of the gaussian approximation. The resulting approximate partition function accurately reproduces thermodynamic quantities such as the free energy, average energy, and specific heat – even at zero temperature – with typical errors of only a few percent. We illustrate the performance of our approximate formula with numerical results for systems of up to ten coupled anharmonic oscillators. These results are compared to “exact” numerical results obtained via Hamiltonian diagonalization for small systems and Path Integral Monte Carlo simulations for larger ones.
Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
17 pages, 5 figures
Growth and prediction of plastic strain in metallic glasses
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Tero Mäkinen, Anshul D. S. Parmar, Silvia Bonfanti, Mikko Alava
Predicting the failure and plasticity of solids remains a longstanding challenge, with broad implications for materials design and functional reliability. Disordered solids like metallic glasses can fail either abruptly or gradually without clear precursors, and the mechanical response depends strongly on composition, thermal history and deformation protocol – impeding generalizable modeling. While deep learning methods offer predictive power, they often rely on numerous input parameters, hindering interpretability, methodology advancement and practical deployment. Here, we propose a macroscopic, physically grounded approach that uses plastic strain accumulation in the elastic regime to robustly predict deformation and yield. This method reduces complexity and improves interpretability, offering a practical alternative for disordered materials. For the Cu-Zr-(Al) metallic glasses prepared with varied annealing, we identify two limiting regimes of plastic strain growth: power-law in poorly annealed and exponential in well-annealed samples. A physics-informed framework with Bayesian inference extracts growth parameters from stress-strain data within $ \sim$ 5% strain, enabling early prediction of bulk response and yield point, well before the failure. The predictive performance improves with annealing, and bulk plasticity correlates with the microscopic plastic activity from scattered to growth near yielding. This work presents a physically interpretable and experimentally relevant framework for predicting plasticity and failure in metallic glasses from early mechanical response, offering both theoretical insights and practical tools for material characterization and design.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
Spin-split magnon bands induce pure spin current in insulating altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Altermagnets offer a promising platform for dissipationless spin transport by combining zero net magnetization with spontaneous non-relativistic spin splitting. However, their magnonic transport properties remain largely unexplored. Here, we develop a quantum-kinetic theory for thermally driven magnon currents that cleanly separates Berry-curvature-driven intrinsic contributions from Drude-like scattering-dependent terms. Applying this framework to a collinear honeycomb antiferromagnet with anisotropic next-nearest-neighbor exchange and Dzyaloshinskii-Moriya interaction, we reveal spin-split magnon bands that support both intrinsic and extrinsic spin Nernst and Seebeck currents. For realistic parameters, we predict a sizable magnon spin-splitting angle (about 3.3 degrees) and a pure transverse spin current capable of exerting a strong spin-splitter torque suitable for magnetization switching.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
14 pages and 4 figures. We invite comments and feedback
Solving the Gross-Pitaevskii Equation with Quantic Tensor Trains: Ground States and Nonlinear Dynamics
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Qian-Can Chen, I-Kang Liu, Jheng-Wei Li, Chia-Min Chung
We develop a tensor network framework based on the quantic tensor train (QTT) format to efficiently solve the Gross-Pitaevskii equation (GPE), which governs Bose-Einstein condensates under mean-field theory. By adapting time-dependent variational principle (TDVP) and gradient descent methods, we accurately handle the GPE’s nonlinearities within the QTT structure. Our approach enables high-resolution simulations with drastically reduced computational cost. We benchmark ground states and dynamics of BECs–including vortex lattice formation and breathing modes–demonstrating superior performance over conventional grid-based methods and stable long-time evolution due to saturating bond dimensions. This establishes QTT as a powerful tool for nonlinear quantum simulations.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 12 figures
Signature of gate tunable superconducting network in twisted bilayer graphene
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Yingbo Wang, Yingzhuo Han, Lu Cao, Xun-Jiang Luo, Yucheng Xue, Jiefei Shi, Xiaomeng Wang, Xiangjia Bai, Junnan Jiang, Ziyi Tian, Kenji Watanabe, Takashi Taniguchi, Fengcheng Wu, Qing-feng Sun, Hong-Jun Gao, Yuhang Jiang, Jinhai Mao
Twisted van der Waals materials provide a tunable platform for investigating two-dimensional superconductivity and quantum phases. Using spectra-imaging scanning tunneling microscopy, we study the superconducting states in twisted bilayer graphene and track their evolution from insulating phases. Gate-dependent spectroscopic measurements reveal two distinct regimes: under-doped ({\nu} = -2.3) and optimally doped ({\nu} = -2.6). In the under-doped regime, partial superconductivity arises, forming a network interspersed with non-gapped regions. At optimal doping, the entire unit cell demonstrates superconductivity, with gap size modulation showing an anti-correlation with the local density of states. This gate-dependent transition from an insulating phase to a modulated superconductor uncovers an unexpected spatial hierarchy in pairing behavior and offers direct microscopic insights to constrain theories of superconductivity in moiré systems.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 4 figures
Astrophysical Quantum Matter Revisited: Flat-Band Topological States on a Zero-Flux Dipole Sphere
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
We study strongly correlated fractional topological phases on a two-sphere threaded by a magnetic dipole field with globally vanishing flux. Solving the Dirac equation in this background produces spheroidal wavefunctions forming a highly degenerate manifold of normalizable zero modes, with degeneracy proportional to the total absolute flux. We introduce a non-Abelian spin gauge field near the equator to hybridize the north and south domain-confined modes, forming a global flat band. Projecting interactions into this band yields Laughlin-type correlated states. The entanglement spectrum shows a chiral tower consistent with a virtual edge, demonstrating bulk-edge correspondence in a closed geometry. This generalizes the zero-flux flat-band construction of \cite{Parhizkar:2024som} to curved backgrounds, with potential applications to synthetic and astrophysical systems.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Astrophysical Phenomena (astro-ph.HE), High Energy Physics - Theory (hep-th)
4 pages RevTex style
Intertwined Orders in a Quantum-Entangled Metal
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Junyoung Kwon, Jaehwon Kim, Gwansuk Oh, Seyoung Jin, Kwangrae Kim, Hoon Kim, Seunghyeok Ha, Hyun-Woo J. Kim, GiBaik Sim, Bjorn Wehinger, Gaston Garbarino, Nour Maraytta, Michael Merz, Matthieu Le Tacon, Christoph J. Sahle, Alessandro Longo, Jungho Kim, Ara Go, Gil Young Cho, Beom Hyun Kim, B. J. Kim
Entanglement underpins quantum information processing and computing, yet its experimental quantification in complex, many-body condensed matter systems remains a considerable challenge. Here, we reveal a highly entangled electronic phase proximate to a quantum metal-insulator transition, identified by resonant inelastic x-ray scattering interferometry. This approach reveals that entanglement across atomic sites generates characteristic interference patterns, which our model accurately reproduces, enabling extraction of a full entanglement spectrum and resolution of the underlying quantum states. Our analysis of the pyrochlore iridate Nd2Ir2O7 demonstrates that the system undergoes pronounced quantum fluctuations in its spin, orbital and charge degrees of freedom, even in the presence of a long-range ‘all-in-all-out’ antiferromagnetic order. Importantly, the observed entanglement signatures facilitate the coexistence of multiple exotic symmetry-breaking orders. Complementary investigations using Raman spectroscopy corroborate the presence of these hidden orders and their emergent excitations. In particular, we observe a two-magnon-bound state below the lowest single-magnon excitation energy, which, together with split phonon modes, provides strong evidence for cubic symmetry-breaking orders of magnetic origin juxtaposed with the all-in-all-out order. Our work thus establishes a direct link between quantum entanglement and emergent unconventional orders, opening new avenues for investigating quantum materials.
Strongly Correlated Electrons (cond-mat.str-el)
Observation of Electride-like $s$ States Coexisting with Correlated $d$ Electrons in NdNiO$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Chihao Li, Yutong Chen, Xiang Ding, Yezhao Zhuang, Nan Guo, Zhihui Chen, Yu Fan, Jiahao Ye, Zhitong An, Suppanut Sangphet, Shenglin Tang, Xiaoxiao Wang, Hai Huang, Haichao Xu, Donglai Feng, Rui Peng
Despite exhibiting a similar $ d_{x^2-y^2}$ band character to cuprates, infinite-layer nickelates host additional electron pockets that distinguish them from single-band cuprates. The elusive orbital origin of these electron pockets has led to competing theoretical scenarios. Here, using polarization-dependent and resonant angle-resolved photoemission spectroscopy (ARPES), we determine the orbital character of the Fermi surfaces in NdNiO$ _2$ . Our data reveal that the electron-like pocket arises predominantly from interstitial $ s$ states, with negligible contributions from rare-earth 5$ d$ and 4$ f$ orbitals near the Fermi level. The observation of well-defined quantum well states indicates a uniform distribution of these interstitial electrons throughout the film thickness. By comparing with electronic structure of LaNiO$ _2$ , we find that the rare-earth element modulates the Ni-derived bands and hopping integrals through a chemical pressure effect. These findings clarify the role of rare-earth elements in shaping the low-energy electronic structure and establish the presence of electride-like interstitial $ s$ states in a correlated oxide system, where electrons occupy lattice voids rather than atomic orbitals. The electride-like character offer new insight into the self-doping and superconductivity in infinite-layer nickelates.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
7pages, 4 figures
Generation of new quadratic coefficients within Ginzburg-Landau theory: Applications for specific heat calculations in various high-temperature superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Feulefack Ornela Claire, Keumo Tsiaze Roger Magloire, Tsague Fotio Carlos, Danga Jeremie Edmond, Fotue Alain Jerve, Mahouton Norbert Hounkonnou
We revisit Landau’s theory by renormalizing quadratic coefficients from nonlinear polynomial equations to adapt them to the system’s dimensionality. These coefficients are employed to perform detailed specific-heat calculations for several high-temperature superconductors near the superconducting transition. We phenomenologically explain the change in the specific heat jump using Ginzburg-Landau theory, which is applicable to any spatial arrangement and interactions between electrons that influence the system’s symmetries. We discuss the effects that may lead to the rapid and non-monotonic variation of the specific heat jump, $ \Delta{C_p}/T_{c}$ , across the transition over relatively small ranges of fluctuations, focusing particularly on changes attributed to the Sommerfeld coefficient in the normal state. We quantitatively explain the considerable reduction, disappearance, or significant enhancement of the specific heat anomaly at the superconducting transition, considering strong fluctuation corrections to the Ginzburg-Landau theory of low-dimensional systems. Additionally, we study the evolution of specific heat jumps by varying the system’s dimensionality and discuss the results in relation to experimental observations of specific-heat jumps in iron-, yttrium-, and bismuth-based superconductors, as well as in $ \beta$ -pyrochlore oxides superconductors like $ KOs_2O_6$ .
Superconductivity (cond-mat.supr-con)
AMS-LaTeX v1.5, 18 pages with 9 figures
Acoustoelectric superlattices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Eli Meril, Unmesh Ghorai, Tobias Holder, Rafi Bistritzer
We introduce a new class of tunable periodic structures, formed by launching two obliquely propagating surface acoustic waves on a piezoelectric substrate that supports a two-dimensional quantum material. The resulting acoustoelectric superlattice exhibits two salient features. First, its periodicity is widely tunable, spanning a length scale intermediate between moiré superlattices and optical lattices, enabling the formation of narrow, topologically nontrivial energy bands. Second, unlike moiré systems, where the superlattice amplitude is set by intrinsic interlayer tunneling and lattice relaxation, the amplitude of the acoustoelectric potential is externally tunable via the surface acoustic wave power. Using massive monolayer graphene as an example, we demonstrate that varying the frequencies and power of the surface acoustic waves enables in-situ control over the band structure of the 2D material, generating flat bands and nontrivial valley Chern numbers, featuring a highly localized Berry curvature.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 + 5 pages, 8 figures
CEMP: a platform unifying high-throughput online calculation, databases and predictive models for clean energy materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Jifeng Wang, Jiazhe Ju, Ying Wang
The development of materials science is undergoing a shift from empirical approaches to data-driven and algorithm-oriented research paradigm. The state-of-the-art platforms are confined to inorganic crystals, with limited chemical space, sparse experimental data and a lack of integrated online computation for rapid validation. Here, we introduce the Clean Energy Materials Platform (CEMP), an open-access platform that integrates high-throughput computing workflows, multi-scale machine learning (ML) models and a comprehensive materials database tailored for clean energy applications. A key feature of CEMP is the online calculation module, which enables fully automatic quantum and molecular dynamics simulations via structured table uploads. CEMP harmonizes heterogeneous data from experimental measurements, theoretical calculation and AI-based predictions for four material classes, including small molecules, polymers, ionic liquids, and crystals. The platform hosts ~ 376,000 entries, including ~6,000 experimental records, ~50,000 quantum-chemical calculations and ~320,000 AI-predicted properties. The database covers 12 critical properties and the corresponding ML models demonstrate robust predictive power with R2 ranging from 0.64 to 0.94, thus ensures rapid material screening, structure-property relationship analysis and multi-objective optimization for clean energy applications. CEMP aims to establish a digital ecosystem for clean energy materials, enabling a closed-loop workflow from data acquisition to material discovery and real-time online validation.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
25 pages, 6 figures
Shear flow of frictional spheroids: lentil-like grains slide more than rice-like
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Jacopo Bilotto, Martin Trulsson, Jean-François Molinari
The rheology of dense granular shear flows is influenced by friction and particle shape. We investigate numerically the impact of non-spherical particle geometries under shear on packing fraction, stress ratios, velocity fluctuations, force distribution, and dissipation mechanisms, for a wide range of inertial numbers, friction coefficients and aspect ratios. We obtain a regime diagram for the dissipation which shows that lentil-like (oblate) particles exhibit an extended sliding regime compared to rice-like (prolate) particles with the same degree of eccentricity. Additionally, we identify non-monotonic behaviour of slightly aspherical particles at low friction, linking it to their higher fluctuating rotational kinetic energy. We find that angular velocity fluctuations are generally reduced when particles align with the flow, except in highly frictional rolling regimes, where fluctuations collapse onto a power-law distribution and motion becomes less correlated. Moreover, for realistic friction coefficients power dissipation tends to concentrate along the major axis aligned with the flow, where slip events are more frequent. We also show that flat particles develop stronger fabric anisotropy than elongated ones, influencing macroscopic stress transmission. These findings provide new insights into the role of particle shape in granular mechanics, with implications for both industrial and geophysical applications.
Soft Condensed Matter (cond-mat.soft)
Direct observation of distinct bulk and edge nonequilibrium spin accumulation in ultrathin MoTe$_2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Fangchu Chen, Kamal Das, Bowen Yang, Chuangtang Wang, Shazhou Zhong, Diana Golovanova, He Ren, Tianyang Wang, Xuan Luo, Yuping Sun, Liuyan Zhao, Guo-Xing Miao, Binghai Yan, Adam W. Tsen
Low-symmetry two-dimensional (2D) topological materials such as MoTe$ _2$ host efficient charge-to-spin conversion (CSC) mechanisms that can be harnessed for novel electronic and spintronic devices. However, the nature of the various CSC mechanisms and their correlation with underlying crystal symmetries remain unsettled. In this work, we use local spin-sensitive electrochemical potential measurements to directly probe the spatially dependent nonequilibrium spin accumulation in MoTe$ _2$ flakes down to four atomic layers. We are able to clearly disentangle contributions originating from the spin Hall and Rashba-Edelstein effects and uncover an abundance of unconventional spin polarizations that develop uniquely in the sample bulk and edges with decreasing thickness. Using ab-initio calculations, we construct a unified understanding of all the observed CSC components in relation to the material dimensionality and stacking arrangement. Our findings not only illuminate previous CSC results on MoTe$ _2$ but also have important ramifications for future devices that can exploit the local and layer-dependent spin properties of this 2D topological material.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
31pages,19figures
Coexistent multifractal mesoscopic fluctuations in Integer Quantum Hall Transition and in Orbital Hall Transition
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Nathan L. Pessoa, Antônio M. S. Macêdo, Anderson L. R. Barbosa
We show that the integer quantum Hall transition in a disordered nanowire with orbital momentum-space texture connected to four terminals is accompanied by an orbital Hall transition. We applied a multifractal detrended fluctuation analysis and found that both conductance fluctuations in the integer quantum Hall transition (IQHT) and orbital-conductance fluctuations in the orbital Hall transition (OHT) display multifractal behavior. We argue that this multifractality is primarily related to disorder, which gives rise to the strong fluctuations that are fingerprints of IQHT and OHT, but is also a consequence of the fact that the nanowire has finite size, which causes a weakening of the multifractality in a certain range of values of disorder strength followed by a new regime of increasing multifractality with increasing disorder strength. Furthermore, our findings indicate that OHT can bring novel insights to future IQHT analysis.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
The role of dimensionality in the magnetic properties of CeIn$_3$ nanowires
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
M. H. Carvalho, D. Zau, A. P. Reyes, R. Cong, S. D. House, H. P. Pizzi, J. Thompson, A. M. Caffer, D.S. Passos, R. C. Santos, G. S. Freitas, K. R. Pirota, R. R. Urbano, P. J. G. Pagliuso
In this work, we have explored the Metallic-Flux Nanonucleation method to synthesize single crystals and nanowires (diameter $ \approx$ 170 nm) of CeIn$ _{3}$ and compare their properties. The effects of reduced dimensionality were systematically investigated using Energy Dispersive Spectroscopy (EDS), Selected area electron diffraction (SAED), magnetic susceptibility, heat capacity, and Nuclear Magnetic Resonance (NMR). Semi-quantitative EDS analysis revealed a Ce:In ratio of 1:3.1(1), and the SAED results confirmed that the nanowires are polycrystalline with a cubic unit cell. Magnetic susceptibility, specific heat, and NMR data indicated a suppression of the antiferromagnetic transition to $ T_N$ $ \approx$ 2.4 K compared to the bulk value ($ \approx$ 10 K). Furthermore, NMR analysis at temperatures below 2.8 K showed a reduced quadrupole frequency, $ \nu_Q$ $ \approx$ 1.77(2) MHz, and provided evidence of polycrystalline nanowires formed within the nanoporous alumina template, in agreement with SAED results. We attribute these findings to an increasing magnetic order frustration induced by dimensionality in CeIn$ _{3}$ nanowires.
Strongly Correlated Electrons (cond-mat.str-el)
Floquet-Engineering Weyl Points and Linked Fermi Arcs from Straight Nodal Lines
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Dongling Liu, Zheng-Yang Zhuan, Zhongbo Yan
Floquet engineering provides a powerful and flexible method for modifying the band structures of quantum materials. While circularly polarized light has been shown to convert curved nodal lines in three-dimensional semimetals into Weyl points, such a transformation is forbidden for an isolated straight nodal line. In this work, we uncover a dramatic shift in this paradigm when multiple straight nodal lines intersect. We observe that circularly polarized light not only gaps them into Weyl points but also induces unprecedented surface-state Fermi arcs that extend across the entire surface Brillouin zone and form a linked topological structure. These findings advance our fundamental understanding of light-driven transitions in topological semimetals and unveil a unique Weyl semimetal phase defined by linked Fermi arcs. We discuss potential exotic phenomena arising from this phase, applications of our predictions to spin-splitting antiferromagnets, and the extension of this Weyl semimetal phase to classical systems.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 4 figures
Efficient transport of indirect excitons in a van der Waals heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Zhiwen Zhou, W. J. Brunner, E. A. Szwed, H. Henstridge, L. H. Fowler-Gerace, L. V. Butov
Exciton transport is fundamental for understanding transport phenomena in bosonic systems and for embracing excitation energy transfer in materials. Spatially indirect excitons (IXs) are composed of electrons and holes in separated layers. Long IX lifetimes allow them to form quantum bosonic states and travel long distances. In this work, we measured IX transport in a MoSe$ _2$ /WSe$ _2$ van der Waals heterostructure by time-resolved photoluminescence imaging. These measurements probe the kinetics of IX cloud expansion and reveal the transport characteristics. We found IX transport with anomalously high diffusivity, orders of magnitude higher than for regular diffusive exciton transport in van der Waals heterostructures. This efficient IX transport agrees with long-range ballistic transport and is consistent with the Bose-Hubbard theory prediction of superfluid in moire superlattices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Universal shape-dependence of quantum entanglement in disordered magnets
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-08 20:00 EDT
Natalie Love, István A. Kovács
Disordered quantum magnets are not only experimentally relevant, but offer efficient computational methodologies to calculate the low energy states as well as various measures of quantum correlations. Here, we present a systematic analysis of quantum entanglement in the paradigmatic random transverse-field Ising model in two dimensions, using an efficient implementation of the asymptotically exact strong disorder renormalization group method. The phase diagram is known to be governed by three distinct infinitely disordered fixed points (IDFPs) that we study here. For square subsystems, it has been recently established that quantum entanglement has a universal logarithmic correction due to the corners of the subsystem at all three IDFPs. This corner contribution has been proposed as an “entanglement susceptibility”, a useful tool to locate the phase transition and to measure the correlation length critical exponent. Towards a deeper understanding, we quantify how the corner contribution depends on the shape of the subsystem. While the corner contribution remains universal, the shape-dependence is qualitatively different in each universality class, also confirmed by line segment subsystems, a special case of skeletal entanglement. Therefore, unlike in conformally invariant systems, in general different subsystem shapes are versatile probes to unveil new universal information on the phase transitions in disordered quantum systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
8 pages, 8 figures
Deciphering the interplay between wetting and chemo-mechanical fracture in lithium-ion battery cathode materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Wan-Xin Chen, Luis J. Carrillo, Arnab Maji, Xiang-Long Peng, Joseph Handy, Sarbajit Banerjee, Bai-Xiang Xu
Crack growth in lithium-ion battery electrodes is typically detrimental and undesirable. However, recent experiments suggest that stabilized fracture of cathode active materials in liquid electrolytes can increase electrochemically active surfaces, shorten diffusion pathway, enhance (de)lithiation and improve overall capacity. To decipher the fundamental couplings between electrolyte wetting and fracture evolution and evaluate their influences on macroscopic battery performance, we conducted an integrated experiment-simulation study on $ \alpha$ -V2O5 single crystals and polycrystalline NCM as model cathode materials. Despite synthesis challenges, single-crystal $ \alpha$ -V2O5 offers clearer fundamental insights than polycrystalline counterparts with grain-boundary complexities. Fracture patterns and lithiation heterogeneities on the samples were mapped using advanced scanning techniques after chemical (de)lithiation cycles, exhibiting excellent agreements with simulations by the developed multiphysics model. Results reveal a mutually reinforcing interplay between wetting and fracture: (i) electrolyte infiltration at fracture surfaces enhances (de)lithiation and compositional heterogeneity; (ii) wetting influences fracture dynamics, including fracture modes, propagation distance and directionality. The validated modelling framework is further applied to simulations on polycrystalline NCM particles under constant-current (dis)charging, highlighting the critical role of wetting in promoting fracture and improving overall capacity. This work bridges fundamental understanding of wetting-fracture coupling with practical implications for battery performance optimization via controlled fracture engineering.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Nitrogen-related short-range order in Fe-Ni-Cr austenitic stainless steels: first principles and cluster expansion study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Tianyu Su, Brian J. Blankenau, Namhoon Kim, Jessica A. Krogstad, Elif Ertekin
Nitrogen (N) is a key alloying element that enhances the performance of Fe-Ni-Cr austenitic stainless steels, improving austenite stability, corrosion resistance, and yield strength. However, the role of N in modifying chemical ordering, particularly short-range order (SRO) and long-range order (LRO), is complex due to the multi-sublattice nature and magnetic interactions in these alloys. In this work, we combine first-principles calculations with the spin cluster expansion (spin CE) method to systematically investigate the effects of N on chemical ordering in Fe-Ni-Cr alloys. Our atomistic models confirm a strong affinity between N and Cr, which drives the formation of N-Cr SRO and, at higher N concentrations, stabilizes M4N-type ordered phases (M = metal). Monte Carlo simulations reveal that low N concentrations promote local N-Cr or N-N SRO, while increasing N content leads to the emergence of Cr-and N-rich LRO structures. We also show that the presence of N suppresses intrinsic Fe-Cr and Ni-Cr SRO by competing with these interactions, particularly at high concentrations. The impact of Cr content on ordering diminishes as N approaches its solubility limit. These findings are consistent with experimental observations in high-N austenitic steels. Finally, we discuss the influence of kinetic and magnetic effects on SRO evolution in high-N alloys. This study provides a comprehensive framework for understanding N-driven chemical ordering and offers insights into microstructural changes during nitriding processes.
Materials Science (cond-mat.mtrl-sci)
Scaling laws for doublet craters formed by low-velocity impacts of unequal-mass spheres into a granular bed
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Haruto Kitagawa, Ririha Obara, Yu Matsuda
Understanding the formation mechanism of doublet craters is an important challenge for advancing knowledge in astronomy and granular physics. In this study, we investigated craters formed by low-velocity impacts of two steel spheres with different masses into a granular bed. Even when the masses were different, a figure-eight-shaped doublet crater and a central ridge were observed, similar to the case with equal masses. However, the resulting shape became asymmetric even without a time delay between impacts. The total length of the doublet crater increased depending on the spacing between the two spheres and the ratio of their impact energies. These results followed a theoretical model based on a scaling law, where the crater diameter is proportional to the one-fourth power of the impact energy. A model was also developed to describe the crater overlap, which increases as the spheres become closer. It was also shown that the crater diameters vary with the time difference, and that the second impact tends to form a larger crater due to fluidization induced by the first.
Soft Condensed Matter (cond-mat.soft)
Optimized Bistable Vortex Memory Arrays for Superconducting In-Memory Matrix-Vector Multiplication
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Mustafa Altay Karamuftuoglu, Changxu Song, Beyza Zeynep Ucpinar, Sasan Razmkhah, Massoud Pedram
Building upon previously introduced Bistable Vortex Memory (BVM) as a novel, nonvolatile, high-density, and scalable superconductor memory technology, this work presents a methodology that uses BVM arrays to address challenges in data-driven algorithms and neural networks, specifically focusing on matrix-vector multiplication (MVM). The BVM approach introduces a novel superconductor-based methodology for in-memory arithmetic, achieving ultra-high-speed and energy-efficient computation by utilizing BVM arrays for in-memory computation. The design employs a tiled multiplier structure where BVM’s inherent current summation capability is combined with Quantizer Buffer (QB) cells to convert the analog accumulated current into a variable number of digital Single Flux Quantum (SFQ) pulses. These pulses are then processed by T1 adder cells, which handle binary addition and carry propagation, thereby forming a complete functional multiplier unit. This paper thus presents an efficient MVM architecture that uses these BVM-based multipliers in a systolic array configuration to enable parallel computation. A key innovation is an optimized BVM array structure specifically tailored for multiplication applications, involving a restructuring of Sense Lines (SLs) with diagonal connections to reduce area and an adjusted input scheme to enhance computational efficiency compared to the general-purpose BVM array design. We demonstrate the efficacy of this approach with a 4-bit multiplier operating at 20 GHz with 50 ps latency and an MVM structure demonstrating operation at 20 GHz. Furthermore, we showcase how this multiplier design can be extended to support Multiply-Accumulate (MAC) operations. This work paves the way for power-efficient neural networks by enabling high-speed in-memory computation.
Superconductivity (cond-mat.supr-con), Emerging Technologies (cs.ET)
arXiv admin note: text overlap with arXiv:2406.08871
Anomalous Ionic Conductivity along the Coherent $Σ$3 Grain Boundary in ThO2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Miaomiao Jin, Jilang Miao, Marat Khafizov, Beihan Chen, Yongfeng Zhang, David H. Hurley
Understanding oxygen diffusion along grain boundaries (GBs) is critical for controlling ionic conductivity in oxide ceramics. GBs are typically thought to enhance ionic transport due to structural disorder and increased free volume. In this study, we report an unexpected anomaly: the $ \Sigma 3(111)$ GB in thorium dioxide (ThO$ _2$ ), despite its compact and coherent structure, exhibits significantly higher oxygen ionic conductivity compared to the more open GB ($ \Sigma 19$ as an example). Using atomistic simulations based on a machine learning interatomic potential, we revealed that the high conductivity in the $ \Sigma 3$ GB arises from a collective diffusion mechanism involving highly correlated atomic motion reminiscent of a superionic state. In contrast, the $ \Sigma 19$ GB follows conventional pipe diffusion, consistent with its more open structure. This comparison highlights that enhanced GB conductivity is not simply correlated with free volume, but can occur from specific structural motifs that enable collective transport. These findings provide new guidance for designing GB-engineered oxides with targeted ionic transport properties for energy applications.
Materials Science (cond-mat.mtrl-sci)
Prethermal inverse Mpemba effect
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Koudai Sugimoto, Tomotaka Kuwahara, Keiji Saito
The inverse Mpemba effect is a counterintuitive phenomenon in which a system, initially in thermal equilibrium and prepared at different temperatures below that of the final equilibrium state, relaxes to the final state more rapidly when starting from a lower initial temperature. We extend this concept to the relaxation toward a prethermal state in isolated quantum systems. By examining a simple model that exhibits prethermalization, we demonstrate that this effect indeed manifests under periodic driving. We further discuss the realization of this phenomenon in a variety of systems within a unified theoretical framework.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
9 pages, 7 figures
Tuning electronic correlations in the Kagome metals $RT_3$B$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
Savita Chaudhary, Armando Consiglio, Jaskaran Singh, Domenico Di Sante, Ronny Thomale, Yogesh Singh
The $ RT_3$ B$ _2$ ($ R=$ Y, Lu, $ T=$ Co, Os) family hosts a perfect kagome lattice of $ T$ atoms, offering an interesting platform to investigate the interplay of electronic structure, superconductivity, and lattice dynamics. Here, we compare two members of this family, LuOs$ _3$ B$ _2$ and YCo$ _3$ B$ _2$ , with similar crystallography but differing chemical composition, leading to distinct electronic correlation strengths and spin-orbit coupling effects. We confirm superconductivity in LuOs$ _3$ B$ _2$ with $ T_c = 4.75$ K, while YCo$ _3$ B$ _2$ remains non-superconducting above 1.8K. First-principles estimates of the electron-phonon coupling for LuOs$ _3$ B$ _2$ are consistent with its observed $ T_c$ and suggest a moderate coupling strength. Both materials exhibit kagome-derived electronic features, including quasi-flat bands, Dirac cones, and van Hove singularities. Fermi surface calculations reveal quasi-one-dimensional behavior along the $ c$ -axis in YCo$ _3$ B$ _2$ , in contrast to the more three-dimensional Fermiology of LuOs$ _3$ B$ _2$ . Phonon calculations for LuOs$ _3$ B$ _2$ show imaginary modes, indicating potential lattice instabilities. Experimental estimates of the Wilson and Kadowaki-Woods ratios point to non-negligible electronic correlations in both compounds.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
11 pages, 9 figures, 1 table
Quantized conductance in a CVD-grown nanoribbon with hidden Rashba effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Jianfei Xiao, Yiwen Ma, Congwei Tan, Kui Zhao, Yunteng Shi, Bingbing Tong, Peiling Li, Ziwei Dou, Xiaohui Song, Guangtong Liu, Jie Shen, Zhaozheng Lyu, Li Lu, Hailin Peng, Fanming Qu
Quantized conductance in quasi-one-dimensional systems not only provides a hallmark of ballistic transport, but also serves as a gateway for exploring quantum phenomena. Recently, a unique hidden Rashba effect attracts tremendous attention, which arises from the compensation of opposite spin polarizations of a Rashba bilayer in inversion symmetric crystals with dipole fields, such as bismuth oxyselenide ($ \mathrm{Bi}{2}\mathrm{O}{2}\mathrm{Se}$ ). However, investigating this effect utilizing conductance quantization is still challenging. Here we report the conductance quantization observed in a chemical vapor deposition (CVD)-grown high-mobility $ \mathrm{Bi}{2}\mathrm{O}{2}\mathrm{Se}$ nanoribbon, where quantized conductance plateaus up to $ 44\cdot 2e^{2}/{h}$ ($ e$ is the elementary charge, $ h$ is the Planck constant, and the factor $ 2$ results from spin degeneracy) are achieved at zero magnetic field. Due to the hidden Rashba effect, the quantized conductance remains in multiples of $ 2e^{2}/{h}$ without Zeeman splitting even under magnetic field up to $ 12$ T. Moreover, within a specific range of magnetic field, the plateau sequence exhibits the Pascal triangle series, namely $ (1,3,6,10,15\dots )\cdot 2e^{2}/{h}$ , reflecting the interplay of size quantization in two transverse directions. These observations are well captured by an effective hidden Rashba bilayer model. Our results demonstrate $ \mathrm{Bi}{2}\mathrm{O}{2}\mathrm{Se}$ as a compelling platform for spintronics and the investigation of emergent phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 4 figures
The size effect on nucleation process during solidification of metals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
A.S. Nuradinov, K.A. Sirenko, I.A. Nuradinov, O.V. Chystiakov, D.O. Derecha
This work investigates the mechanisms of crystal nucleation in metal melts, in dependence on the influence of their shape and volume. Investigations were conducted on both thin flat and bulk samples prepared of low-temperature Wood’s metal alloy and transparent organic media (camphene and diphenylamine). The study revealed that in flat samples, the nucleation rate is primarily influenced by the activity of the mold wall surface, which is affected by melt overheating and subcooling, while in bulk samples, supercooling and nucleation are additionally influenced by factors such as impurity activity, temperature, and density fluctuations.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
14 pages, 1 table 8 figures, 18 references
DFT-Guided Operando Raman Characterization of Ni-Based Phases Relevant to Electrochemical Systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Harol Moreno Fernández, Siavash Karbasizadeh, Esmaeil Adabifiroozjaei, Leopoldo Molina-Luna, Jan P. Hofmann, Mohammad Amirabbasi
We present a phase-resolved investigation of Ni-based oxides and hydroxides relevant to the oxygen evolution reaction (OER), combining ground-state DFT+U calculations with operando and in situ Raman spectroscopy, supported by high-resolution TEM. Five crystalline phases-cubic and hexagonal NiO, monoclinic and trigonal Ni(OH)2, and NiOOH-are systematically characterized in terms of their vibrational and electronic structure. Although the DFT models are idealized (0 K, defect-free, no solvation), they serve as clean, phase-specific references for interpreting complex experimental spectra. Cubic NiO is confirmed to be dynamically and electronically stable, consistent with dominant Raman modes observed experimentally. Despite dynamic instabilities in phonon dispersions, hexagonal NiO is structurally verified via TEM, suggesting substrate- or defect-stabilized metastability. Ni(OH)2 polymorphs are both vibrationally stable semiconductors, with the trigonal phase exhibiting stronger spin polarization. NiOOH exhibits spin-polarized electronic states across the Brillouin zone, consistent with its asymmetric band structure under ferromagnetic ordering. Independently, phonon calculations reveal soft modes near the Gamma-point, indicating dynamic instability under idealized conditions, yet operando Raman spectra align closely with calculated zone-center modes. However, introducing 0.03 Angstrom symmetry-breaking displacements relaxes the NiOOH lattice off its saddle point, removing imaginary phonon modes and stabilizing the phase. This integrated framework demonstrates how idealized DFT can reveal intrinsic fingerprints that anchor the interpretation of vibrational and electronic responses in catalytically active, dynamically evolving Ni-based materials.
Materials Science (cond-mat.mtrl-sci)
The Ferroelectric Superconducting Field Effect Transistor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
Alessandro Paghi, Laura Borgongino, Elia Strambini, Giorgio De Simoni, Lucia Sorba, Francesco Giazotto
The ferroelectric field-effect transistor (Fe-FET) is a three-terminal semiconducting device first introduced in the 1950s. Despite its potential, a significant boost in Fe-FET research occurred about ten years ago with the discovery of ferroelectricity in hafnium oxide. This material has been incorporated into electronic processes since the mid-2000s. Here, we observed ferroelectricity in a superconducting Josephson FET (Fe-JoFET) operating at cryogenic temperatures below 1 Kelvin. The Fe-JoFET was fabricated on the InAsOI platform, which features an InAs epilayer hosted by an electrical insulating substrate, using HfO2 as the gate insulator, making it a promising candidate due to its ferroelectric properties. The Fe-JoFET exhibits significant hysteresis in the switching current and normal-state resistance transfer characteristics, which depend on the range of gate voltages. This phenomenon opens a new research area exploring the interaction between ferroelectricity and superconductivity in hybrid superconducting-semiconducting systems, with potential applications in cryogenic data storage and computation. Supporting this, the Fe-JoFET was operated as a cryogenic superconducting single memory cell, exhibiting both dissipative and non-dissipative states. Its non-volatility was tested over a 24-hour measurement period. We also demonstrated that the Fe-JoFET can retain information at temperatures above the superconductor critical temperature, resulting in a temperature-fault-tolerant memory cell resistant to temperature oscillations or, in the worst case, cryostat faults.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
16 pages, 4 figures, SI at the end of the manuscript. arXiv admin note: text overlap with arXiv:2412.16221, arXiv:2410.11721
Methodology of signal spectral analysis in various Kron model geometries
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Artur Michalak, Maciej Dolecki, Krzysztof Pomorski, Wojciech Nowakowski, Eryk Halubek
This work presents experimental and theoretical comparison in the modelling of the quantum wave function of single-electron in semiconductor nanowire via classical analog electronics based hardware emulator with the use of Kron concept. Thus we are able to express the semiconductor single-electron devices of linear or closed circle topology as present in position-based qubits that can be mapped essentially to one dimensional Kron model implemented experimentally. We have also represented a two dimensional single-electron wave function in Krons model and point out future experiments to be conducted.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 8 figures
The occupation dependent DFT-1/2 method
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Shengxin Yang, Jiangzhen Shi, Kan-Hao Xue, Jun-Hui Yuan, Xiangshui Miao
There has been a high demand in rectifying the band gap under-estimation problem in density functional theory (DFT), while keeping the computational load at the same level as local density approximation. DFT-1/2 and shell DFT-1/2 are useful attempts, as they correct the spurious electron self-interaction through the application of self-energy potentials, which pull down the valence band. Nevertheless, the self-energy potential inevitably disturbs the conduction band, and these two methods fail for semiconductors whose hole and electron are entangled in the same shell-like regions. In this work, we introduce the occupation-dependent DFT-1/2 method, where conduction band states are not subject to the additional self-energy potential disturbance. This methodology works for difficult cases such as $ \text{Li}_2\text{O}_2$ , $ \text{Cu}_2\text{O}$ and two-dimensional semiconductors. Using a shell-like region for the self-energy potential, and allowing for downscaling of the atomic self-energy potential (with an $ A$ < 1 factor), the occupation-dependent shell DFT+$ A$ -1/2 method yields more accurate conduction band and valence band edge levels for monolayer $ \text{MoS}_2$ , compared with the computationally demanding hybrid functional approach.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
19 pages, 10 figures, 1 table
Multipole phases in a type of spin/fermion ladders with local conserved quantities and generalizations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
We study spin/fermion ladder models with multipole phases, which are traditional transverse-field-Ising phases formed by multipole moments. These phases feature non-trivial order with zero magnetization. The multipole models have dimer local conserved quantities that are Ising terms of spin. The Hilbert spaces are locally fragmented into independent sectors described effectively by {\it higher-order spin}. For dipole models, we consider two ladder geometries and work out the phase diagrams. Different phases of the model can be distinguished experimentally with the dynamical structure factor. Higher-order multipole models are obtained by introducing more dimer conserved quantities. The phases are characterized by the values of the local conserved quantities and the transverse-Ising phases of the higher-order spin.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 4 figures
Ferroelectrically Controlled Chirality Switching of Weyl Quasiparticles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Zeling Li, Yu liu, Le Du, Fengyu Li, Zhifeng Liu, Lei Li, Lei Wang, Botao Fu, Xiao-Ping Li
Weyl quasiparticles, as gapless low-energy excitations with nontrivial chirality, have garnered extensive interest in recent years. However, archieving effective and reversible control over their chirality (topological charge) remains a major challeng due to topological protection. In this work, we propose a ferroelectric mechanism to switch the chirality of Weyl phonons, where the reversal of ferroelectric polarization is intrinsically coupled to a simultaneous reversal of the chirality of Weyl points. This enables electric-field-driven control over the topological properties of phonon excitations. Through a comprehensive symmetry analysis of polar space groups, we identify 27 groups capable of hosting symmetry-protected Weyl phonons with chiral charges $ C = 1$ , $ 2$ , and $ 3$ , whose chirality can be reversed via polarization switching. The first-principles calculations are performed to screen feasible material candidates for each type of chirality, yielding a set of prototypical ferroelectric compounds that realize the proposed mechanism. As a representative example, K$ _2$ ZnBr$ _4$ hosts the minimal configuration of two pairs of Weyl phonons. Upon polarization reversal, the chirality of all Weyl points is inverted, accompanied by a reversal of associated topological features such as Berry curvature and surface phonon arcs. These findings provide a viable pathway for dynamic, electrical control of topological band crossings and open new avenues for chirality-based phononic applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Severe Plastic Deformation of Ceramics by High-Pressure Torsion: Review of Principles and Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Kaveh Edalati, Jacqueline Hidalgo-Jiménez, Thanh Tam Nguyen, Hadi Sena, Nariman Enikeev, Gerda Rogl, Valery I. Levitas, Zenji Horita, Michael J. Zehetbauer, Ruslan Z. Valiev, Terence G. Langdon
Ceramics are typically brittle at ambient conditions due to their covalent or ionic bonding and limited dislocation activities. While plasticity, and occasionally superplasticity, can be achieved in ceramics at high temperatures through thermally activated phenomena, creep, and grain boundary sliding, their deformation at ambient temperature and pressure remains challenging. Processing under high pressure via the high-pressure torsion (HPT) method offers new pathways for severe plastic deformation (SPD) of ceramics. This article reviews recent advances in HPT processing of ceramics, focusing primarily on traditional ceramics (e.g., oxides, carbides, nitrides, oxynitrides) and to a lesser extent advanced ceramics (e.g., silicon, carbon, perovskites, clathrates). Key structural and microstructural features of SPD-processed ceramics are discussed, including phase transformations and the generation of nanograins and defects such as vacancies and dislocations. The properties and applications of these deformed ceramics are summarized, including powder consolidation, photoluminescence, bandgap narrowing, photovoltaics, photocatalysis (dye degradation, plastic waste degradation, antibiotic degradation, hydrogen production, CO2 conversion), electrocatalysis, thermoelectric performance, dielectric performance, and ion conductivity for Li-ion batteries. Additionally, the article highlights the role of HPT in synthesizing novel materials, such as high-entropy ceramics (particularly high-entropy oxides), black oxides, and high-pressure polymorphs, which hold promise for energy and environmental applications.
Materials Science (cond-mat.mtrl-sci)
Induced Zeeman effect of moiré surface states in topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Recently, moiré superlattices have been found on the surface of topological insulators due to the rotational misalignment of topmost layers. In this work, we study the effects of moiré superlattices on the Landau levels of topological surface states. We find that an extra Zeeman term besides the intrinsic one can be induced by the orbital effect of the magnetic field in moiré surface states. As a result, the originally field-independent zeroth Landau level of moiré surface states could be tilted by the out-of-plane magnetic field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
4 pages + 1 page references, 2 figures,
Ultrafast non-equilibrium magnon generation and collapse of spin-orbit hybridization gaps in iron
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-08 20:00 EDT
Xinwei Zheng, Shabnam Haque, Christian Strüber, Martin Weinelt
We distinguish between longitudinal and transverse spin excitations in the ultrafast response of iron by probing exchange splitting {\Delta}Eex and magnetic linear dichroism (MLD) in time- and angleresolved photoemission. Comparing spin-split partner bands at the Fermi level shows that {\Delta}Eex remains constant upon optical excitation. In contrast, the different MLD response of spin-orbitsplit valence bands reveals non-equilibrium, transverse spin dynamics. Magnon generation in Fe is ultrafast, electronic band specific, and drives the collapse of spin-orbit hybridization gaps.
Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
3 figures
Universal Diagnostic Criterion for Intrinsic Superconducting Diode Effect
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
The intrinsic superconducting diode effect (SDE) is distinguished from the Josephson diode effect (JDE) by its manifestation of nonreciprocal critical current phenomena within a monolithic superconductor, typically linked to finite-momentum Cooper pairing. The long-standing assumption that SDE requires co-breaking of time-reversal and inversion symmetries proves to be necessary but not sufficient. In this work, we propose a universal diagnostic criterion. Embodied in two concise inequalities, this criterion enables convenient and intuitive assessment of whether an intrinsic SDE can emerge in a given system without requiring extensive numerical calculations. Furthermore, our universal criterion provides explicit design guidelines for material systems exhibiting intrinsic SDE.
Superconductivity (cond-mat.supr-con)
7+7 pages, 2 figures, comments are welcome
Quantum transport in nitrogen-doped nanoporous graphenes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Gaetano Calogero, Isaac Alcón, Alan E. Anaya Morales, Nick Papior, Pol Febrer, Aron W. Cummings, Miguel Pruneda, Stephan Roche, Mads Brandbyge
Bottom-up on-surface synthesized nanoporous graphenes (NPGs), realized as 2D arrays of laterally covalently bonded pi-conjugated graphene nanoribbons (GNRs), are a family of carbon nanomaterials which are receiving increasing attention for nanoelectronics and biosensing. Recently, a so-called hybrid-NPG (hNPG) was synthesized, featuring an alternating sequence of doped and non-doped GNRs, resulting in a band staggering effect in its electronic structure. Such a feature is appealing for photo-catalysis, photovoltaics and even carbon nanocircuitry. However, to date, little is known about the transport properties of hNPG and its derivatives, which is key for most applications. Here, via Green’s functions simulations, we study the quantum transport properties of hNPGs. We find that injected carriers in hNPG spread laterally through a number of GNRs, though such spreading may take place exclusively through GNRs of one type (doped or non-doped). We propose a simple model to discern the key parameters determining the electronic propagation in hNPGs and explore alternative hNPG designs to control the spreading/confinement and anisotropy of charge transport in these systems. For one such design, we find that it is possible to send directed electric signals with sub-nanometer precision for as long as one micrometer - a result first reported for any NPG.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph)
16 pages, 5 figures
Torsional Behavior of Carbon-Doped Ferrous Nanowires: Atomic-Scale Insights from MD Simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Charith L. Hirimuthugodage, Laalitha S.I. Liyanage
This study investigates the torsional mechanical properties of pristine iron (Fe) and carbon-doped iron (FeC) nanowires with [001] orientation through molecular dynamics simulations utilizing the Modified Embedded Atom Method (MEAM) potential developed by Liyanage et al. for accurately modeling Fe-C interactions in body-centered cubic structures. Systematic analysis across carbon concentrations (0 - 10%), temperatures (1 - 900 K), and cross-sectional dimensions 10a, 13a, 15a, ( where a = 2.81 Angstrom represents the lattice constant ) within the LAMMPS environment reveals that increasing carbon content weakens grain boundaries, reducing the maximum shear stress required to reach the critical torsional angle, while higher temperatures promote phase transitions from elastic to plastic deformation due to enhanced atomic vibrations, and larger cross-sections exhibit higher shear stress resistance attributed to strengthening effects from the outer atomic layers. By elucidating these interrelationships between carbon content, temperature, and dimensional factors, this work provides fundamental insights into the mechanical behavior of FeC nanowires under torsional loading conditions, offering valuable guidance for their potential applications in nanoelectromechanical systems, nanorobotic actuators, and advanced structural materials where precise control of mechanical properties is essential.
Materials Science (cond-mat.mtrl-sci)
15 pages, 18 figures
Unlocking high coercivity at room temperature in phase modified MoS$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Zainab Chowdhry, Kushal Mazumder, Praveen Hegde, Pramoda K. Nayak, Vidya Praveen Bhallamudi
Two-dimensional (2D) materials showing room-temperature magnetism and high coercivity are desired for combining magnetism with semiconducting properties useful for spintronics. In this work, the magnetic properties of the 1T phase of MoS$ _2$ have been studied at room temperature. We observe ferromagnetism with a coercivity of ~0.3 T and a maximum saturation magnetization of 0.26 emu/g at room temperature. This is the highest among coercivities reported so far in 2D magnets at room temperature. MoS$ _2$ nanosheets are prepared using a single-step hydrothermal synthesis with a relative 1T-phase reaching up to 77%. We report a correlation between the structural and magnetic characteristics via interplanar distance and coercivity. The increase in interplanar distance is also accompanied by an increase in the 1T phase. Our results pave a useful way of controlling the coercivity and saturation magnetization in a 2D magnet with applications in spintronics and low-power quantum devices.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
16 pages, 4 figures
Stress-induced Martensitic transformation in epitaxial Ni-Mn-Ga thin films and its correlation to optical and magneto-optical properties
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
M. Makeš, J. Zázvorka, M. Hubert, P. Veřtát, M. Rameš, J. Zemen, O. Heczko, M. Veis
The optical and magneto-optical properties of thin epitaxial Ni-Mn-Ga films, with thicknesses ranging from 8 to 160 nm, were investigated across the spectral range of 0.7-6.4 eV. The films were deposited by DC magnetron sputtering on MgO substrate with stress-mediating Cr buffer layer. Structural and magnetic characterization revealed an stress-induced martensitic transformation for the films thicker than 80 nm, while thinner films remained in austenite structure deformed by substrate constraint. Both X-type and Y-type twin domains were observed in martensitic samples. Magneto-optical polar Kerr effect spectra showed notable evolution with film thicknesses, demonstrating changes in electronic structure of Ni-Mn-Ga. A combination of spectroscopic ellipsometry and magneto-optical Kerr spectroscopy allowed for the deduction of the spectral dependence of full permittivity tensor of investigated samples. Three magneto-optical transitions were fitted to the spectra of non-diagonal permittivity using semiclassical theory, showing strong correlations with in-plane coercivity. Observed correlations highlight the impact of substrate-induced strain on Ni-Mn-Ga films and provide insights into the electronic structure changes associated with the martensitic transformation.
Materials Science (cond-mat.mtrl-sci)
Computing dielectric spectra in molecular dynamics simulations: using a cavity to disentangle self and cross correlations
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Dielectric spectra are typically obtained in molecular dynamics (MD) simulations by analyzing the fluctuations, in the absence of an applied electric field, of the total dipole moment of the simulation box. We compare this standard method with a protocol that focuses on a virtual cavity whose size is chosen to include short-range dipolar cross-correlations, while excluding long-range correlations that are affected by the choice of electrostatic boundary conditions. We tested this protocol on three non-polarizable systems with different dielectric permittivities. We showed that it produces the same dielectric spectra as the standard method while being less sensitive to noise. The question of the decomposition of a dielectric spectrum into self and cross contributions is discussed in the context of both methods. We propose that, for a liquid with a sufficiently high dielectric permittivity, the cavity protocol yields a self-spectrum consistent with the electrostatic boundary conditions applicable to the experimental situation.
Soft Condensed Matter (cond-mat.soft)
9 pages, 8 figures, 2 tables
Variational Approach to the Snake Instability of a Bose-Einstein Condensate Soliton
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-08 20:00 EDT
Umut Tanyeri, Mehmet Atakan Gürkan, Ahmet Keleş, Mehmet Özgur Oktel
Solitons are striking manifestations of nonlinearity, encountered in diverse physical systems such as water waves, nonlinear optics, and Bose-Einstein condensates (BECs). In BECs, dark solitons emerge as exact stationary solutions of the one-dimensional Gross-Pitaevskii equation. While they can be long-lived in elongated traps, their stability is compromised in higher dimensions due to the snake instability, which leads to the decay of the soliton into vortex structures among other excitations. We investigate the dynamics of a dark soliton in a Bose-Einstein condensate confined in an anisotropic harmonic trap. Using a variational ansatz that incorporates both the transverse bending of the soliton plane and the emergence of vortices along the nodal line, we derive equations of motion governing the soliton’s evolution. This approach allows us to identify stable oscillation modes as well as the growth rates of the unstable perturbations. In particular, we determine the critical trap anisotropy required to suppress the snake instability. Our analytical predictions are in good agreement with full numerical simulations of the Gross-Pitaevskii equation.
Quantum Gases (cond-mat.quant-gas)
13 pages, 7 figures
Supersymmetric properties of one-dimensional Markov generators with the links to Markov-dualities and to shape-invariance-exact-solvability
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
For diffusion process involving the force $ F(x)$ and the diffusion coefficient $ D(x)$ , the continuity equation $ \partial_t P_t(x)=- \partial_xJ_t(x)$ gives the dynamics of the probability $ P_t( x)$ in terms of the current $ J_t( x)=F(x)P_t(x)-D(x)\partial_x P_t(x)={\cal J}P_t( x)$ obtained from $ P_t( x) $ via the application of the first-order differential current-operator $ {\cal J}$ . So the dynamics of the probability $ P_t( x)$ is governed by the factorized Fokker-Planck generator $ {\cal F}=-\partial_x{\cal J}$ , while the dynamics of the current $ J_t( x)$ is governed by its supersymmetric partner $ {\hat {\cal F} }= - {\cal J}\partial_x$ , so that their right and left eigenvectors are directly related using the two intertwining relations $ {\cal J}{\cal F}=-{\cal J}\partial_x{\cal J}={\hat {\cal F}}{\cal J}$ and $ {\cal F}\partial_x=-\partial_x{\cal J}\partial_x=\partial_x{\hat {\cal F} }$ . We also describe the link with the factorization of the adjoint $ {\cal F}^{\dagger}=\frac{d}{dm(x)}\frac{d}{ds(x)} $ in terms of the scale function $ s(x)$ and speed measure $ m(x)$ . We then analyze how the supersymmetric partner $ {\hat {\cal F} } = - {\cal J} \partial_x$ can be re-interpreted in two ways: (1) as the adjoint $ {\mathring {\cal F}}^{\dagger} ={\mathring {\cal J} }^{\dagger} \partial_x$ of the Fokker-Planck generator $ {\mathring {\cal F}}=- \partial_x{\mathring {\cal J} }$ associated to the dual force $ {\mathring F}(x)=-F(x)-D’(x)$ , that unifies various known Markov dualities; (2) as the non-conserved Fokker-Planck generator $ {\tilde {\cal F}}_{nc} = -\partial_x{\tilde {\cal J}}-{\tilde K }(x)$ involving the force $ {\tilde F}(x)=F(x) +D’(x)$ and the killing rate $ {\tilde K }(x)=-F’(x)-D’’(x)$ , with application to shape-invariance-solvability. Finally, we describe how all these ideas can be also applied to Markov jump processes with nearest-neighbors transition rates $ w(x \pm 1,x)$ .
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
28 pages
Spin-orbit coupling in digital alloyed InGaAs quantum wells
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Jason T. Dong, Yilmaz Gul, Irene Villar Rodriguez, Aaron N. Engel, Connor P. Dempsey, Stuart N. Holmes, Michael Pepper, Christopher J. Palmstrøm
Increasing the spin-orbit coupling in InGaAs quantum wells is desirable for applications involving spintronics and topological quantum computing. Digital alloying is an approach towards growing ternary quantum wells that enables asymmetric interfaces and compositional grading in the quantum well, which can potentially modify the spin-orbit coupling in the quantum well. The spin-orbit coupling of the quantum wells is extracted from beating patterns in the low magnetic field magnetoresistance. Digital alloying is found to modify the spin-orbit coupling by up to 138 meV\textnormalÅ. The changes induced in the spin-orbit coupling can be qualitatively understood as being due to modifications in the interfacial Rashba spin-orbit coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Variability of hole spin qubits in planar Germanium
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Biel Martinez, Yann-Michel Niquet
Hole spin qubits in Ge/GeSi heterostructures benefit from the clean environment of epitaxial interfaces and from the intrinsic spin-orbit coupling that enables efficient electrical control, which makes them promising candidates for quantum computation. However, spin-orbit coupling also enhances the sensitivity to electrical disorder, potentially increasing variability. In this work, we perform numerical simulations in a realistic device geometry to quantify the variability of the charge and spin properties of Ge qubits induced by charge traps at the SiGe/oxide interfaces. We show that while the variability of charge properties remains moderate, spin properties (g-factors and Rabi frequencies) show significant dispersion. We explore the implications of this variability for large-scale architectures, and provide guidelines to minimize variability both in terms of interface quality requirements and optimal operation strategies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Momentum transfer in the ponderomotive potential of near-infrared laser pulses leads to sizable energy shifts and electron-wavepacket squeezing in time-resolved ARPES
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Xinwei Zheng, Martin Weinelt, Christian Strüber
We observe momentum transfer in the ponderomotive potential of near-infrared (NIR) laser pulses in time- and angle-resolved photoemission spectroscopy (tr-ARPES) experiments with ultrashort extreme ultraviolet probe pulses. Acceleration of photoelectrons in the transient grating provided by an intense laser pulse reflected at a surface leads to delay-dependent oscillations of electric kinetic energies. Photon and electron momenta determine the oscillation frequency. We experimentally observe and theoretically simulate electron yield modulations driven by a novel electron-energy bunching effect. Measurement results are simulated and fitted with high accuracy. Complete reversion of the ponderomotive momentum transfer allows for retrieval of the undisturbed initial state and the transient band structure for overlapping pump and probe pulses.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
research article, 9 pages, 8 figures
A Pyridyl-Benzimidazole Based Ruthenium(II) Complex as Optical Sensor: Targeted Cyanide Detection and Live Cell Imaging Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Sudhanshu Naithani, Franck Thetiot, Vikas Yadav, Saakshi Saini, Partha Roy, Samar Layek, Tapas Goswami, Sushil Kumar
The extreme toxicity of cyanide (\ce{CN^-}) ions in diverse environmental media has garnered significant attention toward the design of well-organized molecular probes for their selective and sensitive detection. In this context, we present a monometallic Ru(II) complex (Ru-1), based on the 2-(pyridin-2-yl)-1H-benzo[d]imidazole moiety, acting as a highly selective luminescent probe for \ce{CN^-} recognition in pure water. Additionally, Ru-1 also functions as an efficient sensor for \ce{F^-}, \ce{AcO^-}, and \ce{H2PO4^-} ions, along with \ce{CN^-}, when acetonitrile is used as the solvent system. The binding constant ($ K_b$ ) and detection limit (LoD) for \ce{CN^-} were determined to be $ 3.05 \times 10^6$ M$ ^{-1}$ and 12.8nM, respectively, in water. The close proximity of the N–H site to the Ru(II) center, along with its notable acidity, were identified as the primary factors responsible for the high selectivity of Ru-1 toward \ce{CN^-} in aqueous media. Job’s plots and density functional theory (DFT) analyses were conducted to support the anion binding mechanism. Furthermore, time-resolved fluorescence (TRF) spectroscopy was employed to evaluate the \ce{CN^-}-induced emission lifetime change of Ru-1 in water. To explore practical applicability, the Ru-1 probe was developed into paper-based strips capable of detecting \ce{CN^-} ions in the millimolar range via the naked eye under 365~nm UV illumination. It was also effectively applied for the detection of \ce{CN^-} in human breast cancer MCF-7 cell lines and natural food sources, such as apple seeds and sprouting potatoes.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
26 pages, 6 figures, 66 references
Journal of Photochemistry and Photobiology A: Chemistry, 453, 115610 (2024)
Equilibrium-preserving Laplacian renormalization group
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Sudo Yi, Seong-Gyu Yang, K.-I. Goh, D.-S. Lee
Diffusion over networks has recently been used to define spatiotemporal scales and extend Kadanoff block spins of Euclidean space to supernodes of networks in the Laplacian renormalization group (LRG). Yet, its ad hoc coarse-graining procedure remains underdeveloped and unvalidated, limiting its broader applicability. Here we rigorously formulate an LRG preserving the equilibrium state, offering a principled coarse-graining procedure. We construct the renormalized Laplacian matrix preserving dominant spectral properties using a proper, quasi-complete basis transformation and the renormalized adjacency matrix preserving mean connectivity from equilibrium-state flows among supernodes. Applying recursively this equilibrium-preserving LRG to various hypergraphs, we find that in hypertrees with low spectral dimensions vertex degree and hyperedge cardinality distributions flow toward Poissonian forms, while in hypergraphs lacking a finite spectral dimension they broaden toward power-law forms when starting from Poissonian ones, revealing how informational, structural, and dynamical scale-invariances are interrelated.
Statistical Mechanics (cond-mat.stat-mech), Physics and Society (physics.soc-ph)
6 pages and 3 figures in main text, 16 pages and 12 figures in supplemental material
Stochastic size control of self-assembled filaments
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Maximilian C. Hübl, Carl P. Goodrich
Controlling the size and shape of assembled structures is a fundamental challenge in self-assembly, and is highly relevant in material design and biology. Here, we show that specific, but promiscuous, short-range binding interactions make it possible to economically assemble linear filaments of user-defined length. Our approach leads to independent control over the mean and width of the filament size distribution and allows us to smoothly explore design trade-offs between assembly quality (spread in size) and cost (number of particle species). We employ a simple hierarchical assembly protocol to minimize assembly times, and show that multiple stages of hierarchy make it possible to extend our approach to the assembly of higher-dimensional structures. Our work provides a simple and experimentally straightforward solution to size control that is immediately applicable to a broad range of systems, from DNA origami assemblies to supramolecular polymers and beyond.
Soft Condensed Matter (cond-mat.soft)
Beyond LSDA and Thomas-Fermi: A Hartree-Fock Analysis of Spherical Nanoparticles in the Jellium Approximation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
A comprehensive Hartree-Fock analysis of the ground-state electronic structure of spherical gold nanoparticles modeled within the jellium approximation is carried out for all systems containing up to 132 delocalized electrons. Emphasis is placed on resolving the energy-level ordering, properly describing the electron density tail and associated charge spill-out, and assessing the accuracy of local exchange and kinetic energy potentials. The calculations are performed on a high-resolution real-space grid to ensure numerical precision. Significant discrepancies are observed between the exchange energy given by the Hartree-Fock approximation and the local spin density approximation (LSDA) in both the inner and outer regions of the nanoparticle. To address these differences, a refined expression of the one-electron exchange energy density as an explicit function of the charge density is proposed. Similarly, the failure of the Thomas-Fermi kinetic energy model near the surface of the nanoparticle is resolved by introducing an improved expression for the one-electron kinetic energy density.
Materials Science (cond-mat.mtrl-sci), Atomic and Molecular Clusters (physics.atm-clus)
Non-ergodic one-magnon magnetization dynamics of the kagome lattice antiferromagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
H. Schlüter, J. Schnack, J. Eckseler (Bielefeld University)
The present view of modern physics on non-equilibrium dynamics is that generic systems equilibrate or thermalize under rather general conditions, even closed systems under unitary time evolution. The investigation of exceptions thus not only appears attractive, in view of quantum computing where thermalization is a threat it also seems to be necessary. Here, we present aspects of the one-magnon dynamics on the kagome lattice antiferromagnet as an example of a non-equilibrating dynamics due to flat bands. Similar to the one-dimensional delta chain localized eigenstates also called localized magnons lead to disorder-free localization and prevent the system from equilibration.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
11 pages, 13 figures
Anderson-Skin dualism
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-08 20:00 EDT
Shan-Zhong Li, Linhu Li, Shi-Liang Zhu, Zhi Li
We report a novel localization phenomenon that emerges in non-Hermitian and quasiperiodic coupled systems, which we dub ``Anderson-Skin (AS) dualism”. The emergence of AS dualism is due to the fact that non-Hermitian topological systems provide non-trivial topological transport channels for disordered systems, causing the originally localized Anderson modes to transform into skin modes, i.e., the localized states within the point gap regions have dual characteristics of localization under periodic boundary condition (PBC) and skin effects under open boundary conditions (OBC). As an example, we analytically prove the 1D AS dualism through the transfer matrix method. Moreover, by discussing many-body interacting systems, we confirm that AS dualism is universal.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
4+5 pages,3+3 figures
Geometry-Induced Chiral Currents in a Mesoscopic Helicoidal Quantum Well
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
We introduce a mesoscopic quantum well whose confinement and chirality emerge solely from the intrinsic torsion of a finite helicoidal metric. This purely geometric construction requires no external gates or fields: the metric itself induces both a harmonic radial potential and a torsion-driven Zeeman term that breaks the $ m \leftrightarrow -m$ degeneracy. By imposing hard-wall boundary conditions at $ z = \pm L/2$ , we quantize the axial motion and obtain a genuinely zero-dimensional helicoidal quantum dot. An exact analytic solution reveals an energy spectrum with chiral splitting linear in both the torsion parameter $ \Omega$ and the axial quantum number $ n_z$ . For realistic InAs nanoroll parameters ($ L = 100$ nm, $ \Omega = 5\times10^{6} \mathrm{m^{-1}}$ ), this geometric effect results in a measurable splitting of $ \sim 0.5$ meV. We propose three viable experimental platforms, ultracold atoms in optical traps, femtosecond-written photonic waveguides, and strain-engineered semiconductor nanorolls, where this torsion-induced phenomenon should be accessible with current technology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
11 pages, 9 figures, 1 table
A Generative Diffusion Model for Amorphous Materials
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-08 20:00 EDT
Kai Yang, Daniel Schwalbe-Koda
Generative models show great promise for the inverse design of molecules and inorganic crystals, but remain largely ineffective within more complex structures such as amorphous materials. Here, we present a diffusion model that reliably generates amorphous structures up to 1000 times faster than conventional simulations across processing conditions, compositions, and data sources. Generated structures recovered the short- and medium-range order, sampling diversity, and macroscopic properties of silica glass, as validated by simulations and an information-theoretical strategy. Conditional generation allowed sampling large structures at low cooling rates of 10$ ^{-2}$ K/ps to uncover a ductile-to-brittle transition and mesoporous silica structures. Extension to metallic glassy systems accurately reproduced local structures and properties from both computational and experimental datasets, demonstrating how synthetic data can be generated from characterization results. Our methods provide a roadmap for the design and simulation of amorphous materials previously inaccessible to computational methods.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG)
Main: 19 pages, 5 figures; SI: 22 pages, 16 figures
Machine Learning Study of the Surface Reconstructions of Cu$_{2}$O(111) Surface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Payal Wadhwa, Michael Schmid, Georg Kresse
The atomic structure of the most stable reconstructed surface of cuprous oxide (Cu$ _{2}$ O)(111) surface has been a longstanding topic of debate. In this study, we develop on-the-fly machine-learned force fields (MLFFs) to systematically investigate the various reconstructions of the Cu$ _{2}$ O(111) surface under stoichiometric as well as O- and Cu-deficient or rich conditions, focusing on both ($ \sqrt{3}$ \times$ \sqrt{3}$ )R30° and (2$ \times$ 2) supercells. By utilizing parallel tempering simulations supported by MLFFs, we confirm that the previously described nanopyramidal and Cu-deficient (1$ \times$ 1) structures are the lowest energy structures from moderately to strong oxidizing conditions. In addition, we identify two promising nanopyramidal reconstructions at highly reducing conditions, a stoichiometric and a Cu-rich one. Surface energy calculations performed using spin-polarized PBE, PBE+U, r$ ^{2}$ SCAN, and HSE06 functionals show that the previously known Cu-deficient configuration and nanopyramidal configurations are at the convex hull (and, thus, equilibrium structures) for all functionals, whereas the stability of the other structures depends on the functional and is therefore uncertain. Our findings demonstrate that on-the-fly trained MLFFs provide a simple, efficient, and rapid approach to explore the complex surface reconstructions commonly encountered in experimental studies, and also enhance our understanding of the stability of Cu$ _{2}$ O(111) surfaces.
Materials Science (cond-mat.mtrl-sci)
Main manuscript- 14 pages, 5 figures Supplementary- 5 pages, 6 Figures
Particle-scale origin of quadrupolar non-affine displacement fields in granular solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Evan P. Willmarth, Weiwei Jin, Dong Wang, Amit Datye, Udo D. Schwarz, Mark D. Shattuck, Corey S. O’Hern
In this work, we identify the local structural defects that control the non-affine displacement fields in jammed disk packings subjected to athermal, quasistatic (AQS) simple shear. While complex non-affine displacement fields typically occur during simple shear, isolated effective quadrupoles are also observed and their probability increases with increasing pressure. We show that the emergence of an isolated effective quadrupole requires the breaking of an interparticle contact that is aligned with low-frequency, spatially extended vibrational modes. Since the Eshelby inhomogeneity problem gives rise to quadrupolar displacement fields in continuum materials, we reformulate and implement Eshelby’s equivalent inclusion method (EIM) for jammed disk packings. Using EIM, we show that we can reconstruct the non-affine displacement fields for jammed disk packings in response to applied shear as a sum of discrete Eshelby-like defects that are caused by mismatches in the local stiffnesses of triangles formed from Delaunay triangulation of the disk centers.
Soft Condensed Matter (cond-mat.soft)
Moiré-assisted charge instability in ultrathin RuO$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Philipp Keßler, Andreas Feuerpfeil, Armando Consiglio, Hendrik Hohmann, Ronny Thomale, Jonas Erhardt, Bing Liu, Vedran Jovic, Ralph Claessen, Patrick Härtl, Matteo Dürrnagel, Simon Moser
Ruthenium dioxide (RuO$ _2$ ) has been in the focus of contemporary condensed matter research as a prototypical candidate material for altermagnetism. In the face of daunting evidence for bulk magnetic order despite promising theoretical predictions, it naturally suggests the focus on thin films where Coulomb interactions are dimensionally quenched and may yield a more strongly correlated environment prone to magnetic ordering. Here, we combine scanning tunneling microscopy (STM), density functional theory (DFT), and density matrix renormalization group (DMRG) methods to investigate atomically ordered ultrathin RuO$ _2$ (110) grown on Ru(0001). Contrary to predictions of magnetic order, we observe a nonmagnetic charge density wave (CDW) instability that is driven by Fermi surface nesting within the flat-band surface state, and stabilized by the incommensurate moiré stacking with the substrate. We further identify a nonmagnetic and metastable 2 $ \times$ 2 surface reconstruction that breaks in-plane mirror symmetry and can be reversibly toggled via STM tip manipulation. Our spin-polarized STM measurements find no sign of any magnetic instability at the RuO$ _2$ surface. As much as our findings refute proposals for either bulk or surface magnetism in RuO$ _2$ , we establish ultrathin RuO$ _2$ (110) as an intriguing platform for exploring Moiré-assisted electronic surface order.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Looping metal-support interaction in heterogeneous catalysts during redox reactions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Yue Pan, Shiyu Zhen, Xiaozhi Liu, Mengshu Ge, Jianxiong Zhao, Lin Gu, Dan Zhou, Liang Zhang, Dong Su
Metal-support interfaces fundamentally govern the catalytic performance of heterogeneous systems through complex interactions. Here, utilizing operando transmission electron microscopy, we uncovered a type of looping metal-support interaction in NiFe-Fe3O4 catalysts during hydrogen oxidation reaction. At the NiFe-Fe3O4 interfaces, lattice oxygens react with NiFe-activated H atoms, gradually sacrificing themselves and resulting in dynamically migrating interfaces. Meanwhile, reduced iron atoms migrate to the {111} surface of Fe3O4 support and react with oxygen molecules. Consequently, the hydrogen oxidation reaction separates spatially on a single nanoparticle and is intrinsically coupled with the redox reaction of the Fe3O4 support through the dynamic migration of metal-support interfaces. Our work provides previously unidentified mechanistic insight into metal-support interactions and underscores the transformative potential of operando methodologies for studying atomic-scale dynamics.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
The Hitchhiker’s Guide to Differential Dynamic Microscopy
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-08 20:00 EDT
Enrico Lattuada, Fabian Krautgasser, Maxime Lavaud, Fabio Giavazzi, Roberto Cerbino
Over nearly two decades, Differential Dynamic Microscopy (DDM) has become a standard technique for extracting dynamic correlation functions from time-lapse microscopy data, with applications spanning colloidal suspensions, polymer solutions, active fluids, and biological systems. In its most common implementation, DDM analyzes image sequences acquired with a conventional microscope equipped with a digital camera, yielding time- and wavevector-resolved information analogous to that obtained in multi-angle Dynamic Light Scattering (DLS). With a widening array of applications and a growing, heterogeneous user base, lowering the technical barrier to performing DDM has become a central objective. In this tutorial article, we provide a step-by-step guide to conducting DDM experiments – from planning and acquisition to data analysis – and introduce the open-source software package fastDDM, designed to efficiently process large image datasets. fastDDM employs optimized, parallel algorithms that reduce analysis times by up to four orders of magnitude on typical datasets (e.g., 10,000 frames), thereby enabling high-throughput workflows and making DDM more broadly accessible across disciplines.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Data Analysis, Statistics and Probability (physics.data-an), Optics (physics.optics)
Main text + SI
Spin liquid state in a three-dimensional pyrochlore-like frustrated magnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
U. Jena, S. Kundu, Suheon Lee, Q. Faure, F. Damay, S. Rols, Adam Berlie, S. Petit, Kwang-Yong Choi, P. Khuntia
The three-dimensional frustrated spin lattice in MgCrGaO4, where Cr3+ ions occupy a pyrochlore-like network, exemplifies a quantum magnet with competing interactions, macroscopic degeneracy, and exotic low-energy excitations. Using thermodynamic, electron spin resonance (ESR), muon spin relaxation (muSR), and inelastic neutron scattering (INS) techniques, we observe no magnetic order or spin freezing down to 57 mK, despite a sizable exchange interaction (J= 58 K) between Cr3+ (S=3/2) moments and inherent site disorder. Below the characteristic exchange energy scale, all experimental probes detect the emergence of antiferromagnetic short-range spin correlations, corroborated by magnetic diffuse scattering in the wave vector dependence of low-energy magnetic excitations centered on Q = 1.5 A^-1 in inelastic neutron scattering experiments. The low-temperature specific heat follows a near-quadratic dependence without a gap, consistent with algebraic spin correlations. These results establish MgCrGaO4 as a rare three-dimensional classical spin liquid featuring a highly degenerate ground-state manifold and gapless excitations, offering a strong impetus for the experimental realization of spin liquids in higher-dimensional frustrated quantum magnets.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Quantum Spin Glass in the Two-Dimensional Disordered Heisenberg Model via Foundation Neural-Network Quantum States
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-08 20:00 EDT
Luciano Loris Viteritti, Riccardo Rende, Giacomo Bracci Testasecca, Jacopo Niedda, Roderich Moessner, Giuseppe Carleo, Antonello Scardicchio
We investigate the two-dimensional frustrated quantum Heisenberg model with bond disorder on nearest-neighbor couplings using the recently introduced Foundation Neural-Network Quantum States framework, which enables accurate and efficient computation of disorder-averaged observables with a single variational optimization. Simulations on large lattices reveal an extended region of the phase diagram where long-range magnetic order vanishes in the thermodynamic limit, while the overlap order parameter, which characterizes quantum spin glass states, remains finite. These findings, supported by a semiclassical analysis based on a large-spin expansion, provide compelling evidence that the spin glass phase is stable against quantum fluctuations, unlike the classical case where it disappears at any finite temperature.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
15 pages (including Supplemental Material), 6 figures
Atomistic study of dislocation formation during Ge epitaxy on Si
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Luis Martín-Encinar, Luis A. Marqués, Iván Santos, Lourdes Pelaz
We performed classical molecular dynamics simulations to investigate, from an atomistic point of view, the formation of dislocations during the epitaxial growth of Ge on Si. We show that simulations at 900 and 1000 K with deposition rates of 10$ ^8$ monolayers per second provide a good compromise between computational cost and accuracy. In these conditions, the ratio between the Ge deposition rate and the ad-atom jump rate is analogous to that of out-of-equilibrium experiments. In addition, the main features of the grown film (intermixing, critical film thickness, dislocation typology, and surface morphology) are well described. Our simulations reveal that dislocations originate in low-density amorphous regions that form under valleys of the rough Ge film surface. Atoms are squeezed out of these regions to the surface, releasing the stress accumulated in the film and smoothing its surface. Amorphous regions grow until atoms begin to rearrange in dislocation half-loops that propagate throughout the Ge film. The threading arm ends of the dislocation half-loops move along the surface following valleys and avoiding islands. The film surface morphology affects the propagation path of the dislocation half-loops and the resulting dislocation network.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Instability of the Haldane Phase: Roles of Charge Fluctuations and Hund’s Coupling
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-08 20:00 EDT
We systematically investigate the stability of the symmetry-protected topological (SPT) Haldane phase in spin-1/2 Heisenberg and half-filled Hubbard ladders coupled by ferromagnetic Hund’s interactions. Using density-matrix renormalization group (DMRG) method, we analyze key signatures of the Haldane phase: long-range string order, finite spin gap, and characteristic entanglement spectrum degeneracies. In spin-only Heisenberg ladders, we find immediate onset and continuous strengthening of the Haldane phase with increasing Hund’s coupling. In contrast, the inclusion of charge fluctuations in Hubbard ladders leads to a nontrivial stability regime, revealing a robust yet bounded region where SPT order persists despite significant charge fluctuations. We identify distinct boundaries separating a trivial insulating phase from the Haldane SPT phase, governed by both Coulomb repulsion and Hund’s coupling. Our results highlight the subtle interplay of spin and charge degrees of freedom in correlated itinerant systems and establish essential criteria for observing Haldane physics experimentally in fermionic ladder materials.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 5 figures
Topological defect modes in bilayer acoustic networks
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Renaud Cote, Marc Pachebat, Antonin Coutant
The bulk-boundary correspondence, which relates topological properties of a material in the bulk to the presence of robust modes localized on the edge, is at the core of the now mature field of topological wave physics. More recently, it was realized that in crystalline structures, certain types of defects can host localized modes, in which case the bulk-boundary correspondence has to be replaced by a bulk-defect correspondence. These defect-localized modes are expected to have robust properties owing to their topological origin. In this work, we show how to obtain topological defect modes in a lattice possessing both mirror and chiral symmetry. The defect is obtained by endowing a plaquette with a non-trivial gauge flux. We show that the bulk-defect correspondence is satisfied by introducing appropriate topological invariants. Moreover, the topological defect modes are shown to be highly robust to the introduction of symmetry-preserving disorder. The model is then realized in an acoustic system made of a network of tubes, and the presence of topological defect mode is experimentally clearly demonstrated.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Classical Physics (physics.class-ph)
7+3 pages. 4+3 figures
Variational first-principles approach to self-trapped polarons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Vasilii Vasilchenko, Matteo Giantomassi, Samuel Poncé, Xavier Gonze
The behavior of charge carriers in polar materials is governed by electron-phonon interactions, which affect their mobilities via phonon scattering and may localize carriers into self-induced deformation fields, forming self-trapped polarons. We present a first-principles study of self-trapped polaron formation in paradigmatic polar semiconductors and insulators using the variational polaron equations framework and self-consistent gradient optimization. Our method incorporates long-range corrections to the electron-phonon interaction, essential for finite-size systems. We demonstrate how the variational approach enables the identification of multiple polaronic states and supports the analysis of polarons with arbitrarily large spatial extent via energy filtering. The potential energy surfaces of the resulting polarons exhibit multiple local minima, reflecting distinct, symmetry-broken polaronic configurations in systems with degenerate band edges. Our findings align with previous theoretical studies and establish a robust foundation for future ab initio studies of polarons, especially those employing variational methods.
Materials Science (cond-mat.mtrl-sci)
18 pages (manuscript), 8 pages (supplementary information), 10 figures
Self-consistent moment dynamics for networks of spiking neurons
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Gianni Valerio Vinci, Roberto Benzi, Maurizio Mattia
A novel approach to moment closure problem is used to derive low dimensional laws for the dynamics of the moments of the membrane potential distribution in a population of spiking neurons. Using spectral expansion of the density equation we derive the recursive and nonlinear relation between the moments, such as the mean potential, and the population firing rates. The self-consistent dynamics found relies on the dominant eigenvalues of the evolution operator, tightly related to the moments of the single-neuron inter-spike interval distribution. Contrary to previous attempts our system can be applied both in noise- and drift-dominated regime, and both for weakly and strongly coupled population. We demonstrate the applicability of the theory for the case of a network of leaky integrate-and-fire neurons deriving closed analytical expressions. Truncating the mode decomposition to the first few more relevant moments, results to effectively describe the population dynamics both out-of-equilibrium and in response to strongly-varying inputs.
Statistical Mechanics (cond-mat.stat-mech), Dynamical Systems (math.DS), Neurons and Cognition (q-bio.NC)
Pseudo-likelihood produces associative memories able to generalize, even for asymmetric couplings
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-08 20:00 EDT
Francesco D’Amico, Dario Bocchi, Luca Maria Del Bono, Saverio Rossi, Matteo Negri
Energy-based probabilistic models learned by maximizing the likelihood of the data are limited by the intractability of the partition function. A widely used workaround is to maximize the pseudo-likelihood, which replaces the global normalization with tractable local normalizations. Here we show that, in the zero-temperature limit, a network trained to maximize pseudo-likelihood naturally implements an associative memory: if the training set is small, patterns become fixed-point attractors whose basins of attraction exceed those of any classical Hopfield rule. We explain quantitatively this effect on uncorrelated random patterns. Moreover, we show that, for different structured datasets coming from computer science (random feature model, MNIST), physics (spin glasses) and biology (proteins), as the number of training examples increases the learned network goes beyond memorization, developing meaningful attractors with non-trivial correlations with test examples, thus showing the ability to generalize. Our results therefore reveal pseudo-likelihood works both as an efficient inference tool and as a principled mechanism for memory and generalization.
Statistical Mechanics (cond-mat.stat-mech), Machine Learning (cs.LG)
Statistical characterization of valley coupling in Si/SiGe quantum dots via $g$-factor measurements near a valley vortex
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Benjamin D. Woods, Merritt P. Losert, Nasir R. Elston, M. A. Eriksson, S. N. Coppersmith, Robert Joynt, Mark Friesen
The presence of low-energy valley excitations in Si/SiGe heterostructures often causes spin qubits to fail. It is therefore important to develop robust protocols for characterizing the valley coupling. Here, we show that realistically sized samplings of valley energy distributions tend to dramatically overestimate the average valley coupling. But we find that knowledge of the valley phase, in addition to the valley splitting, can significantly improve our estimates. Motivated by this understanding, we propose a novel method to probe the valley phase landscape across the quantum well using simple $ g$ -factor measurements. An important calibration step in this procedure is to measure $ g$ in a loop enclosing a valley vortex, where the valley phase winds by $ \pm 2\pi$ around a zero of the valley splitting. This proposal establishes an important new tool for probing spin qubits, and it can be implemented in current experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
4+8 pages, 2+3 figures
Defect-induced displacement of topological surface state in quantum magnet MnBi$_2$Te$_4$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Felix Lüpke, Marek Kolmer, Hengxin Tan, Hao Chang, Adam Kaminski, Binghai Yan, Jiaqiang Yan, Wonhee Ko, An-Ping Li
The topological magnet MnBi$ _2$ Te$ _4$ (MBT), with gapped topological surface state, is an attractive platform for realizing quantum anomalous Hall and Axion insulator states. However, the experimentally observed surface state gaps fail to meet theoretical predictions, although the exact mechanism behind the gap suppression has been debated. Recent theoretical studies suggest that intrinsic antisite defects push the topological surface state away from the MBT surface, closing its gap and making it less accessible to scanning probe experiments. Here, we report on the local effect of defects on the MBT surface states and demonstrate that high defect concentrations lead to a displacement of the surface states well into the MBT crystal, validating the theorized mechanism. The local and global influence of antisite defects on the topological surface states are studied with samples of varying defect densities by combining scanning tunneling microscopy (STM), angle-resolved photoemission (ARPES), and density functional theory (DFT). Our findings identify a combination of increased defect density and reduced defect spacing as the primary factors underlying the displacement of the surface states and suppression of surface gap, shedding light to further development of topological quantum materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Dynamics and chaotic properties of the fully disordered Kuramoto model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-08 20:00 EDT
Frustrated random interactions are a key ingredient of spin glasses. From this perspective, we study the dynamics of the Kuramoto model with quenched random couplings: the simplest oscillator ensemble with fully disordered interactions. We answer some open questions by means of extensive numerical simulations and a perturbative calculation (the cavity method). We show frequency entrainment is not realized in the thermodynamic limit and that chaotic dynamics are pervasive in parameter space. In the weak coupling regime, we find closed formulas for the frequency shift and the dissipativeness of the model. Interestingly, the largest Lyapunov exponent is found to exhibit the same asymptotic dependence on the coupling constant irrespective of the coupling asymmetry, within the numerical accuracy.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Chaotic Dynamics (nlin.CD)
11 pages, 7 figures
Magnetic force microscopy versus scanning quantum-vortex microscopy: Probing pinning landscape in granular niobium films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-08 20:00 EDT
A. Yu. Aladyshkin, R. A. Hovhannisyan, S. Yu. Grebenchuk, S. A. Larionov, A. G. Shishkin, O. V. Skryabina, A. V. Samokhvalov, A. S. Mel’nikov, D. Roditchev, V. S. Stolyarov
We provide an overview of the methodology and fundamental principles associated with newly developed experimental technique – scanning quantum-vortex microscopy [Hovhannisyan et al., Commun. Mater., vol. 6, 42 (2025)]. This approach appears promising for experimental studies of vortex pinning phenomena in superconducting films and nanodevices. In particular, we studied the magnetic properties of magnetron-sputtered niobium (Nb) films by low-temperature magnetic force microscopy. As the temperature approaches the superconducting critical temperature, the pinning potential caused by structural defects weakens; consequently, the attractive interaction between the magnetic tip of the cantilever and a single-quantum vortex begins to dominate. In this scenario the magnetic probe is capable of trapping a vortex during the scanning process. Because the dragged vortex continues interacting with structural defects, it serves as an efficient nano-probe to explore pinning potentials and visualize grain boundaries in granular Nb films, achieving resolutions (30 nm) comparable to the superconducting coherence length.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
24 pages, 13 figures
Guidelines for the optimization of hafnia-based ferroelectrics through superlattice engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
Johanna van Gent, Binayak Mukherjee, Ewout van der Veer, Ellen M. Kiens, Gertjan G. Koster, Bart J. Kooi, Jorge Íñiguez-González, Beatriz Noheda
Hafnia-based ferroelectrics are revolutionizing the data storage industry and the field of ferroelectrics, with improved materials and devices being reported monthly. However, full understanding and control has not been reached yet and the ideal material still needs to be found. Here we report ferroelectric hafnia-zirconia superlattices made out of zirconium-substituted hafnia (Hf$ _{1-x}$ Zr$ _x$ O$ _2$ ) sublayers of varying stoichiometries alternating with pure ZrO$ _2$ sublayers. It is observed that the ZrO$ _2$ layers in these superlattices act as a booster for the total remnant polarization (P$ _r$ ). By combining the benefits of the ZrO$ _2$ layers and the added interfaces, which help prevent breakdown, we fabricate superlattices with a total 87.5% ZrO$ _2$ content, exhibiting record polarizations with a 2P$ _r$ value of 84 $ \mu$ C/cm$ ^2$ that can be cycled 10$ ^9$ times, while maintaining a 2P$ _r$ > 20 $ \mu$ C/cm$ ^2$ . Next to these attractive properties, substitution of HfO$ _2$ by the much more abundant ZrO$ _2$ offers a significant step towards the sustainable application of these devices.
Materials Science (cond-mat.mtrl-sci)
Moiré excitons and exciton-polaritons: A review
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Saúl A. Herrera-González, Hugo A. Lara-García, Giuseppe Pirruccio, David A. Ruiz-Tijerina, Arturo Camacho-Guardian
Distinguished by their long lifetimes, strong dipolar interactions, and periodic confinement, moiré excitons provide a fertile territory for realizing interaction-driven excitonic phases beyond conventional semiconductor systems. Formed in twisted or lattice-mismatched van der Waals heterostructures, these excitons are shaped by a periodic potential landscape that enables the engineering of flat bands, strong interactions, and long-lived localised states. This has opened pathways to explore strongly correlated phases, including excitonic insulators, superfluids, and supersolids, potentially stable even at room temperature. When embedded in optical cavities, moiré excitons hybridize with photons to form moiré exciton-polaritons, a new class of quasiparticles exhibiting enhanced optical nonlinearities and novel topological features.
In this review, we survey the theoretical foundations and experimental progress in the field of moiré excitons and polaritons. We begin by introducing the formation mechanisms of moiré patterns in two-dimensional semiconductors, and describe their impact on exciton confinement, optical selection rules, and spin-valley physics. We then discuss recent advances in the realization of many-body excitonic phases and exciton-based probes of electronic correlations. Finally, we explore the novel aspects of moiré polaritons, highlighting their unique nonlinear and topological properties. By bridging quantum optics, nanophotonics, and correlated electron systems, moiré excitons offer a powerful solid-state platform for quantum simulation, optoelectronic applications, and many-body photonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
21 pages + 21 pages of references, 12 figures. Comments are vey welcome
Doping Induced Magnetic and Electronic phase Transition in Ferrimagnetic Half-metallic Mn${4}$Al${11}$ Compound
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-08 20:00 EDT
The future of spintronic and semiconductor applications demands materials with tailored electronic and magnetic properties. This study uses density functional theory to investigate the electronic structure of the half-metallic compound Mn$ _{4}$ Al$ _{11}$ under uniaxial strain and in its Ge-substituted derivatives. Strain analysis shows that although the half-metallic band-gap collapses under strain beyond $ -2%$ , the ferrimagnetic character remains stable. Ge substitution at six inequivalent Al-sites in Mn$ _{4}$ Al$ _{11}$ results in varying degrees of metallicity and magnetic properties. Substitution at Al$ =(000)$ induces a metal-to-insulator transition with an indirect semiconducting gap of $ 0.14~ eV$ . Bonding and hybridization analysis reveals that local Mn-Al interactions due to Ge substitution significantly modify the local electronic structure, causing both electronic and magnetic phase transitions. This work highlights the effectiveness of substitutional doping in tuning half-metallicity and magnetic properties in inorganic solids, enabling the design of materials for future technological applications.
Materials Science (cond-mat.mtrl-sci)
Tunable Intraband and Interband Polarizability in three-dimensional nodal line semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-08 20:00 EDT
Vivek Pandey, Snehasish Nandy, Pankaj Bhalla
Polarizability plays an essential role in characterizing the key phenomena, such as the screening effects, collective excitations, and dielectric functions present in the system. In this study, we investigate the intraband and interband polarizability within the random phase approximation for the three-dimensional nodal line semimetals, specifically for Ca$ _3$ P$ _2$ and ZrSiS. We find both intraband and interband contributions show tunable behavior with the chemical potential, which adds a resonance signature in the behavior of the polarizability. Further, in the long wavelength limit, the results reveal the quadratic dependence on the wave vector by the non-resonant intraband and interband parts of the polarizability. On the other hand, the resonant interband part gives a cubic dependence on the wave vector. In addition, the total polarizability is dominated by the intraband part in the low frequency regime, while in the mid and high frequency regimes, the interband part takes the lead. This study opens avenues for further theoretical and experimental exploration of frequency dependent dielectric properties, paving the way for potential applications in tunable plasmonic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 4 figures