CMP Journal 2025-10-14
Statistics
Nature Physics: 2
Physical Review Letters: 11
arXiv: 102
Nature Physics
Experimental observation of a time rondeau crystal
Original Paper | Phase transitions and critical phenomena | 2025-10-13 20:00 EDT
Leo Joon Il Moon, Paul M. Schindler, Yizhe Sun, Emanuel Druga, Johannes Knolle, Roderich Moessner, Hongzheng Zhao, Marin Bukov, Ashok Ajoy
Conventional phases of matter can be characterized by the symmetries they break, one example being water ice whose crystalline structure breaks the continuous translation symmetry of space. Recently, breaking of time-translation symmetry was observed in non-equilibrium systems, producing so-called time crystals. Here we investigate different kinds of partial temporal ordering, stabilized by non-periodic yet structured drives, which we call the rondeau order. Using carbon-13 nuclear spins in diamond as a quantum simulator, we use microwave driving fields to create tunable short-time disorder in a system exhibiting long-time stroboscopic order. Our spin control architecture allows us to implement a family of driving fields including periodic, aperiodic and structured random drives. We use a high-throughput read-out scheme to continuously observe the spin polarization and its rondeau order, with controllable lifetimes exceeding 4 s. Using degrees of freedom associated with the short-time temporal disorder of rondeau order, we demonstrate the capacity to encode information in the response of observables. Our work broadens the landscape of observed non-equilibrium temporal order, and raises the prospect for the potential applications of driven quantum matter.
Phase transitions and critical phenomena, Quantum simulation, Solid-state NMR
Nodal hybridization in a two-dimensional heavy-fermion material
Original Paper | Electronic properties and materials | 2025-10-13 20:00 EDT
Simon Turkel, Victoria A. Posey, Chin Shen Ong, Sanat Ghosh, Xiong Huang, Asish K. Kundu, Elio Vescovo, Daniel G. Chica, Patrik Thunström, Olle Eriksson, Wolfgang Simeth, Allen Scheie, Angel Rubio, Andrew J. Millis, Xavier Roy, Abhay N. Pasupathy
Metals with partially filled core atomic shells can form quasiparticles at a low temperature arising from the hybridization of the core level and conduction electrons. The thermodynamic and spectroscopic properties of these metals can be understood as those of a simple metal, but with a significant mass enhancement over the free electron mass–commonly referred to as heavy fermions. In most heavy-fermion materials, the hybridization is approximately isotropic in position and momentum space. However, a combination of low dimensionality and symmetry properties of the core-level wavefunctions can give rise to highly anisotropic electronic interactions with the conduction electrons. Here we demonstrate anisotropic hybridization that vanishes along specific directions in momentum space–referred to as nodes–in a lanthanide-based two-dimensional van der Waals heavy-fermion compound, CeSiI. Quasiparticle interference measurements reveal a set of discrete hotspots with high spectral intensity on the Fermi surface. Theoretical modelling and comparison with the quasiparticle interference pattern of the non-heavy-fermion isostructural analogue LaSiI suggest that these features arise from an unconventional electron interaction involving hybridization nodes unique to CeSiI. As a result, the effective mass of the quasiparticles varies by orders of magnitude depending on their direction in momentum space.
Electronic properties and materials
Physical Review Letters
Measuring Full Counting Statistics in a Trapped-Ion Quantum Simulator
Article | Quantum Information, Science, and Technology | 2025-10-14 06:00 EDT
Lata Kh Joshi, Filiberto Ares, Manoj K. Joshi, Christian F. Roos, and Pasquale Calabrese
In quantum mechanics, the probability distribution function and full counting statistics play a fundamental role in characterizing the fluctuations of quantum observables, as they encode the complete information about these fluctuations. In this Letter, we measure these two quantities in a trapped-i…
Phys. Rev. Lett. 135, 160601 (2025)
Quantum Information, Science, and Technology
Atacama Cosmology Telescope, South Pole Telescope, and Chaotic Inflation
Article | Cosmology, Astrophysics, and Gravitation | 2025-10-14 06:00 EDT
Renata Kallosh, Andrei Linde, and Diederik Roest
We show that the simplest generalization of the chaotic inflation model with nonminimal coupling to gravity provides a good match to the results of the latest data release of the Atacama Cosmology Telescope and South Pole Telescope, with .
Phys. Rev. Lett. 135, 161001 (2025)
Cosmology, Astrophysics, and Gravitation
Spontaneous Emission from Electronic Metastable Resonance States
Article | Atomic, Molecular, and Optical Physics | 2025-10-14 06:00 EDT
Amir Sivan, Milan Šindelka, Meir Orenstein, and Nimrod Moiseyev
We demonstrate that calculating the spontaneous emission decay rate from metastable resonance states (states with finite lifetimes embedded in the continuum) requires considering transitions to all continuum states, not just to lower states. This holds even when the lifetimes of the metastable state…
Phys. Rev. Lett. 135, 163001 (2025)
Atomic, Molecular, and Optical Physics
Meissner-like Currents of Photons in Anomalous Superradiant Phases
Article | Atomic, Molecular, and Optical Physics | 2025-10-14 06:00 EDT
Linjun Li, Pengfei Huang, Zi-Xiang Hu, and Yu-Yu Zhang
We present Meissner-like photon currents in a quantum Rabi zigzag chain under staggered synthetic magnetic fields. The ground state of the Meissner superradiant phase hosts persistent chiral edge currents in a sequence of cancellation of antiparallel vortex pairs, akin to surface currents of the Mei…
Phys. Rev. Lett. 135, 163601 (2025)
Atomic, Molecular, and Optical Physics
Two-Dimensional Topological Edge States in Periodic Space-Time Interfaces
Article | Atomic, Molecular, and Optical Physics | 2025-10-14 06:00 EDT
Ohad Segal, Yonatan Plotnik, Eran Lustig, Yonatan Sharabi, Moshe-Ishay Cohen, Alexander Dikopoltsev, and Mordechai Segev
Topological edge states in systems of two (or more) dimensions offer scattering-free transport, exhibiting robustness to inhomogeneities and disorder. In a different domain, time-modulated systems, such as photonic time crystals, offer nonresonant amplification drawing energy from the modulation. Co…
Phys. Rev. Lett. 135, 163801 (2025)
Atomic, Molecular, and Optical Physics
Relativistic Oscillating Window Driven by an Intense Laguerre-Gaussian Laser Pulse
Article | Plasma and Solar Physics, Accelerators and Beams | 2025-10-14 06:00 EDT
Yao Meng, Runze Li, and Longqing Yi
High-order harmonic generation by the diffraction of an intense Laguerre-Gaussian (LG) laser beam through a small aperture is studied. It is found that the 2D peripheral electron dynamics at the boundary of the diffraction aperture can facilitate complex interplay between the spin and orbital angula…
Phys. Rev. Lett. 135, 165001 (2025)
Plasma and Solar Physics, Accelerators and Beams
Dissipative Superfluidity in a Molecular Bose-Einstein Condensate
Article | Condensed Matter and Materials | 2025-10-14 06:00 EDT
Hongchao Li, Xie-Hang Yu, Masaya Nakagawa, and Masahito Ueda
Motivated by recent experimental realization of a Bose-Einstein condensate (BEC) of dipolar molecules, we develop superfluid transport theory for a dissipative BEC to show that a weak uniform two-body loss can induce phase rigidity, leading to superfluid transport of bosons without repulsive interac…
Phys. Rev. Lett. 135, 166001 (2025)
Condensed Matter and Materials
Multiband Fractional Thouless Pumps
Article | Condensed Matter and Materials | 2025-10-14 06:00 EDT
Marius Jürgensen, Jacob Steiner, Gil Refael, and Mikael C. Rechtsman
Quantization of particle transport lies at the heart of topological physics. In Thouless pumps--dimensionally reduced versions of the integer quantum Hall effect--quantization is dictated by the integer winding of single-band Wannier states. Here, we show that repulsive interactions can drive a transi…
Phys. Rev. Lett. 135, 166601 (2025)
Condensed Matter and Materials
Altermagnets with Topological Order in Kitaev Bilayers
Article | Condensed Matter and Materials | 2025-10-14 06:00 EDT
Aayush Vijayvargia, Ezra Day-Roberts, Antia S. Botana, and Onur Erten
Building on recent advancements in altermagnetism, we develop a highly frustrated magnetic model with Kitaev-like interactions that integrates key aspects of both quantum spin liquids and altermagnets. While the ground state is a gapless quantum spin liquid, our analysis indicates that an altermagne…
Phys. Rev. Lett. 135, 166701 (2025)
Condensed Matter and Materials
Defects, Parcellation, and Renormalized Negative Diffusivities in Nonhomogeneous Oscillatory Media
Article | Polymers, Chemical Physics, Soft Matter, and Biological Physics | 2025-10-14 06:00 EDT
Marie Sellier-Prono, Massimo Cencini, David Kleinfeld, and Massimo Vergassola
Spatial nonhomogeneities can synchronize clusters of spatially extended oscillators in different frequency plateaus. Motivated by physiological rhythms, we fully characterize the phase diagram of a Ginzburg-Landau (GL) model with a gradient of frequencies. For large gradients and diffusion, the rest…
Phys. Rev. Lett. 135, 168401 (2025)
Polymers, Chemical Physics, Soft Matter, and Biological Physics
Erratum: Elastic Screening of Pseudogauge Fields in Graphene [Phys. Rev. Lett. 134, 046404 (2025)]
Article | | 2025-10-14 06:00 EDT
Christophe De Beule, Robin Smeyers, Wilson Nieto Luna, E. J. Mele, and Lucian Covaci
Phys. Rev. Lett. 135, 169901 (2025)
arXiv
Scaling Properties of Avalanche Activity in the Two-Dimensional Abelian Sandpile Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-14 20:00 EDT
We study the scaling properties of avalanche activity in the two-dimensional Abelian sandpile model. Instead of the conventional avalanche size distribution, we analyze the site activity distribution, which measures how often a site participates in avalanches when grains are added across the lattice. Using numerical simulations for system sizes up to (L = 160), averaged over (10^4) configurations, we determine the probability distribution (P(A, L)) of site activities. The results show that (P(A, L)) follows a finite-size scaling form [ P(A, L) \sim L^{-2} F\Big(\frac{A}{L^2}\Big). ] For small values (A \ll L^2) the scaling function behaves as [ F(u) \sim u^{-1/2}, \quad \text{corresponding to} \quad P(A) \sim \frac{1}{L}, ] while for large activities (A \sim O(L^2)) the distribution decays as [ F(u) \sim \exp\big(-c_3 u - c_4 u^2\big). ] The crossover between these two regimes occurs at [ A^\ast \sim 0.1 , L^2, ] marking the threshold between typical and highly excitable sites. This characterization of local avalanche activity provides complementary information to the usual avalanche size statistics, highlighting how local regions serve as frequent conduits for critical dynamics. These results may help connect sandpile models to real-world self-organized critical systems where only partial local activity can be observed.
Statistical Mechanics (cond-mat.stat-mech), Cellular Automata and Lattice Gases (nlin.CG)
Ensemble-Based Data Assimilation for Material Model Characterization in High-Velocity Impact
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Rong Jin, Guangyao Wang, Xingsheng Sun
High-fidelity simulations are essential for understanding and predicting the behavior of materials under high-velocity impact (HVI) in both fundamental research and practical applications. However, their accuracy relies on material models and parameters that are traditionally obtained through manual fitting to multiple time- and labor-intensive experiments. This study presents an ensemble-based data assimilation (DA) framework to automatically and simultaneously calibrate plasticity, fracture, and equation of state (EOS) parameters from a single HVI test. The framework integrates Smoothed Particle Hydrodynamics for HVI simulations, the ensemble Kalman filter (EnKF) for parameter refinement, and adaptive covariance inflation to mitigate uncertainty underestimation. The approach is demonstrated using synthetic back-face deflection data from an AZ31B magnesium plate to identify Johnson-Cook plasticity/fracture and Mie-Gruneisen EOS parameters. Test cases with biased initial guesses and limited data show the EnKF-based framework accurately recovers sensitive parameters in few iterations, indicated by a convergent ensemble standard deviation. Conversely, insensitive parameters converge to incorrect values with persistently large standard deviations. Limited observational data can still achieve convergence but requires more iterations. Under extreme prior bias, sensitive parameters may exhibit a drift-then-stall behavior with small residual biases. In practice, the ensemble standard deviation thus provides a diagnostic tool to assess parameter sensitivity and calibration accuracy. This study demonstrates the proposed DA framework is a robust and efficient tool for HVI material model characterization.
Materials Science (cond-mat.mtrl-sci), Data Analysis, Statistics and Probability (physics.data-an)
33 pages, 10 figures
Conformal Data for the O(3) Wilson-Fisher CFT from Fuzzy Sphere Realization of Quantum Rotor Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Arjun Dey, Loic Herviou, Christopher Mudry, Andreas Martin Läuchli
We present a model for strongly interacting fermions with internal O(3) symmetry on the fuzzy-sphere that (i) preserves the rotational symmetry of the fuzzy sphere and (ii) undergoes a quantum phase transition in the (2+1)-dimensional O(3) Wilson-Fisher universality class. Using exact diagonalization (ED) and density matrix renormalization group (DMRG), we locate the quantum critical point via conformal perturbation theory and obtain scaling dimensions from finite-size spectra. We identify 24 primary operators and determine some of their operator product expansion coefficients through first-order conformal perturbation theory. The results are benchmarked against conformal bootstrap and large quantum-number expansions and reveal a weakly irrelevant operator that plays a role in dimerized antiferromagnets. Our work establishes the fuzzy sphere as a general framework for quantitatively accessing conformal data in non-Abelian conformal field theories (CFTs).
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
Emergent Network of Josephson Junctions in a Kagome Superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
Tycho J. Blom, Matthijs Rog, Marieke Altena, Andrea Capa Salinas, Stephen D. Wilson, Chuan Li, Kaveh Lahabi
Materials with a Kagome lattice are intensely studied because they host novel, exotic states that combine strong correlations and electronic topology. The AV3Sb5 (A = K, Rb, Cs) group, in particular, is of major interest due to its combination of charge density waves, unconventional superconductivity, and indications of time-reversal symmetry breaking and electronic nematicity. Recently, critical current oscillations in an external magnetic field were observed in an unstructured flake of CsV3Sb5 at low current densities. In this work, we unequivocally show that the origin of these oscillations is a network of Josephson junctions intrinsic to the flake that emerges below its critical temperature. Under radio-frequency radiation, we observe perfectly quantized, integer Shapiro steps. The sensitivity of the step height to the contact placement indicates a rich and complex network of junctions. By performing interference studies along multiple field directions, we demonstrate that the observed interference effects are a result of geometrically small junctions and filamentary supercurrent flow. Upon microstructuring the flake, prominent features of the interference pattern are fully preserved, illustrating the localized nature of these flakes and their stability to thermal cycles. These results pave the way for determining the exact nature of superconductivity in the AV3Sb5 family.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 3 figures
Electron-electron scattering processes in quantum wells in a quantizing magnetic field: II. Scattering in the case of two subbands
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Electron-electron scattering processes involving Landau levels of two subband are considered. A matrix of electron-electron scattering rates containing all tipes of transitions between Landau levels is calculated/ This matrix is analized, and the relative rates of transitions of different types are determined. The effect of the quantizing magnetic field orientation on electron-electron scattering processes is ectablished.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
33 pages, 21 Figures
Zh.Exp.Teor.Fiz., Vol. 168 (10), 537 (2025)
Dipole Alignment and Layered Flow Structure in Pressure-Driven Water Transport through MoS$_{2}$ Membranes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
João Victor Lemos Vale, Lucas Cesena, Bruno H. S. Mendonça, Elizane E. de Moraes
Efficient water transport through nanostructure membranes is essential for advancing filtration and desalination technologies. In this study, we investigate the flow of water through molybdenum disulfide (MoS$ _{2}$ ) nanopores of varying diameters using molecular dynamics simulations. The results demonstrate that both pore size and atomic edge composition play crucial roles in regulating water flux, molecular organization, and dipole orientation. Larger pores facilitate the formation of layered water structures and promote edge-accelerated flow, driven by strong electrostatic interactions between water molecules and exposed molybdenum atoms. In narrower pores, confinement and asymmetric edge chemistry induce the ordered alignment of dipoles, thereby enhancing directional transport. Velocity and density maps reveal that pore edges act as active zones, concentrating flow and reducing resistance. These findings highlight the significance of pore geometry, surface chemistry, and molecular dynamics in influencing water behavior within MoS$ _{2}$ membranes, providing valuable insights for the design of advanced nanofluidic and water purification systems.
Materials Science (cond-mat.mtrl-sci)
19 pages, 7 figures
Thermoelectric effect at the quantum Hall-superconductor interface
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Jordan T. McCourt, John Chiles, Chun-Chia Chen, Kenji Watanabe, Takashi Tanaguchi, Francois Amet, Gleb Finkelstein
The interfaces of quantum Hall insulators with superconductors have emerged as a promising platform to realise interesting physics that may be relevant for topologically protected quantum computing. However, these interfaces can host other effects which obscure the detection of the desired excitations. Here we present measurements of the thermoelectric effect at the quantum Hall-superconductor interface. We explain the heat transport by considering the formation of a hotspot at the interface, which results in a non-equilibrium distribution of electrons that can propagate across the superconductor through vortex cores. The observed thermoelectric effect results in a voltage which changes sign on quantum Hall plateaus and responds to the rearrangement of vortices in the wire. These observations highlight the complex interplay of thermal and charge phenomena at the quantum Hall – superconductor interfaces and should be considered when interpreting transport measurements in similar systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
10 pages, 4 figures
Rotation of crystal seed during early stages of growth reveals the anisotropy of glass matrix
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
R. Thapa, E. Mustermann, H. Jain, V. Dierolf, M. E. McKenzie
Rotation of crystal seed during the early stages of growth in a glass matrix has been observed due to some torque, contradicting the expectations from the isotropic, uniform structure of the surrounding amorphous matrix. We establish an atomistic origin of this new phenomenon from molecular dynamics simulations using LiNbO3 and LiNbO3-SiO2 glasses as model systems. Effectively, it arises due to non-uniform forces on the seed from the surrounding glass, which appears inhomogeneous and anisotropic on the scale of glass-crystal interface. The seeded crystal growth (SCG) at higher temperatures amplifies this effect due to enhanced atomic dynamics. Silica, when added to LiNbO3 glass, reduces the crystal growth rate due to increased viscosity and restricted atomic mobility across the growth interface, but has minimal effect on the crystal rotation. These findings challenge a general assumption that glass is an isotropic material, especially during the early stage of its crystallization, and provide insights for tailoring the microstructure of widely used glass-ceramics.
Materials Science (cond-mat.mtrl-sci)
Stable High-Order Vortices in Spin-Orbit-Coupled Spin-1 Bose-Einstein Condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-10-14 20:00 EDT
Xin-Feng Zhang, Huan-Bo Luo, Josep Batle, Bin Liu, Yongyao Li
The present contribution explores phase transitions that occur in the ground state (GS) of spin-1 Bose-Einstein condensates (BECs) with spin-orbit coupling (SOC) under the action of gradient
magnetic fields. By solving the corresponding linearized system in an exact fashion, we identify the
conditions under which the GS phase transitions occur, thus transforming excited states into GS.
The study of the full nonlinear system, including both density-density and spin-spin interactions,
is numerically analyzed. For the case of repulsive spin-spin interactions, the results resemble the
linear case, while attractive spin-spin interactions lead to the formation of mixed-states near the GS
phase-transition points. Additionally, higher-order vortex solitons are found to be stable even in
the nonlinear regime. These findings demonstrate that arbitrary winding numbers can be achieved
as corresponding to stable GS and thus contributing to the understanding of topological properties
in SOC BECs.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS)
to be published in Physical Review A
Spin Hall effect in the high-resistivity high-entropy alloy AlCrMoW
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Jyoti Yadav, Felix Janus, Tiago de Oliveira Schneider, Shalini Sharma, Daniel Schröter, Markus Meinert
We study thin films of the high-entropy alloy system Al$ _{x}$ (CrMoW)$ {1-x}$ , grown on Ta seed layers by magnetron co-sputtering. Between $ x=0.2$ and $ x=0.6$ , a resistivity larger than 100$ \mu\Omega$ cm is achieved, with a peak of 180$ \mu\Omega$ cm at $ x=0.5$ . Around the stoichiometric composition AlCrMoW, the alloy forms a bcc solid solution. The harmonic Hall method was used to characterize the spin Hall angle of the alloy series, where a maximum spin Hall angle of $ \theta = -0.12 \pm 0.01$ is observed for $ x=0.25$ . The implied spin Hall conductivity is $ \sigma\mathrm{SH} \approx -72,000 , \hbar/(2e)$ ,S/m. The experimental results show excellent agreement with density functional theory calculations, which show similar trends and values. The results demonstrate that high-entropy alloys with a main-group element component can form a simple crystal structure and show high resistivity. This suggests that a whole new class of materials for spin Hall device engineering is available with simple methods.
Materials Science (cond-mat.mtrl-sci)
6 pages, 3 figures
Raman Digital Twin of Monolayer Janus Transition Metal Dichalcogenides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Johnathan Kowalski, Liangbo Liang
Monolayer transition metal dichalcogenides (TMDs) are a key class of two-dimensional (2D) materials with broad technological potential. Their Janus counterparts exhibit unique properties due to broken out-of-plane symmetry and further enrich the functionalities of TMDs. However, experimental synthesis and identification of Janus TMDs remain challenging. It is thus highly desirable to have a rapid, simple, and in situ characterization technique to monitor, in real time, the conversion process from the parent to Janus structure. Raman spectroscopy stands out for such a task as it is a powerful, non-destructive, and very commonly used tool to characterize 2D materials both in situ and ex situ. To realize the full potential of Raman spectroscopy on rapid characterization of Janus TMDs, we present a computational “Raman digital twin” library for various monolayer Janus TMDs in both 2H and Td phases. We focus on group-6 TMDs: MoS$ _2$ , WS$ _2$ , MoSe$ _2$ , WSe$ _2$ , MoTe$ _2$ , WTe$ _2$ and their Janus variants: MoSSe, MoSTe, MoSeTe, WSSe, WSTe, and WSeTe. Using first-principles density functional theory (DFT), we calculate their vibrational properties and predict distinct Raman fingerprints. These phonon and Raman signatures reflect each material’s structural symmetry and atomic composition, enabling clear identification via Raman spectroscopy. Our theoretical work supports experimental efforts by providing benchmarks for material identification, structural analysis, and quality control. The computational library expedites the discovery and development of Janus 2D materials, facilitating tighter integration between theoretical predictions and experimental validation.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Predicting Crystal Structures and Ionic Conductivity in Li${3}$YCl${6-x}$Br$_{x}$ Halide Solid Electrolytes Using a Fine-Tuned Machine Learning Interatomic Potential
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
This work demonstrates the effectiveness of fine-tuning the CHGNet universal machine learning interatomic potential (uMLIP) to investigate ionic transport mechanisms in ternary halide solid electrolytes of the Li$ _{3}$ YCl$ _{6-x}$ Br$ _{x}$ family (x = 0 to 6), which are promising candidates for solid-state battery applications. We present a strategy for generating ordered structural models from experimentally derived disordered Li$ _{3}$ YCl$ _{6}$ (LYC) and Li$ _{3}$ YBr$ _{6}$ (LYB) structures. These serve as initial configurations for an iterative fine-tuning workflow that couples molecular dynamics (MD) simulations with static density functional theory (DFT) calculations. The fine-tuning process and the resulting improvements in predictive accuracy are benchmarked across energy predictions, structure optimizations, and diffusion coefficient calculations. Finally, we analyze the influence of composition (varied x) on the predicted ionic conductivity in Li$ _{3}$ YCl$ _{6-x}$ Br$ _{x}$ , demonstrating the robustness of our approach for modeling transport properties in complex solid electrolytes.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
20 pages, 6 figures
Polymer Topology and the Depletion Interaction
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
Using a theoretical model we show that ideal ring polymers are stronger depletants than ideal linear polymers of equal radii of gyration, but not of equal hydrodynamic radii. The difference in the depletion-induced force profile is largely controlled by the thickness of the depletion layer. Theory suggests that this thickness is equal to the average extent of a polymer along the direction perpendicular to the surfaces of the colloids. Within the limits of finite-size effects, Molecular Dynamics simulations support this conclusion.
Soft Condensed Matter (cond-mat.soft)
Hydration Free Energies of Linear Alkanes: Evaluating and Correcting Classical Force Field Predictions with Different Water Models
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
Common force fields tend to overestimate the hydration free energies of hydrophobic solutes, leading to an exaggerated hydrophobic effect. We compute the hydration free energies of linear alkanes from methane to eicosane (C$ _{20}$ H$ _{42}$ ) using free energy perturbation with various three-site (SPC/E, OPC3) and four-site (TIP4P/2005, OPC) water models and the TraPPE-UA force field for alkanes. All water models overestimate the hydration free energies, though the four-site models perform better than the three-site ones. By utilizing cavity free energies, we reparameterize the alkane–water well depth to bring simulation results in agreement with experimental and group-contribution estimates. We find that the General Amber Force Field (GAFF) combined with TIP4P/2005 water provides closer estimates of the hydration free energy. The HH alkane model (a reparameterized TraPPE-UA force field) with TIP4P/2005 reproduces experimental hydration free energies. We also show that applying a shifted Lennard–Jones potential leads to systematic deviations in the hydration free energy estimates.
Soft Condensed Matter (cond-mat.soft)
Two-dimensional superconducting diode effect in topological insulator/superconductor heterostructure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
Soma Nagahama, Yuki Sato, Minoru Kawamura, Ilya Belopolski, Ryutaro Yoshimi, Atsushi Tsukazaki, Naoya Kanazawa, Kei S Takahashi, Masashi Kawasaki, Yoshinori Tokura
The superconducting diode effect (SDE) is characterized by the nonreciprocity of Cooper-pair motion with respect to current direction. In three-dimensional (3D) materials, SDE results in a critical current that varies with direction, making the effect distinctly observable: the material exhibits superconductivity in one direction while behaving as a resistive metal in the opposite direction. However, in genuinely two-dimensional (2D) materials, the critical current density is theoretically zero, leaving the manifestation of SDE in the 2D limit an intriguing challenge. Here, we present the observation of SDE in a heterostructure composed of the topological insulator Bi$ _2$ Te$ _3$ and the iron based superconductor Fe(Se,Te) $ -$ a candidate for topological superconductor$ -$ where superconductivity is confined to the 2D limit. The observed I-V characteristics reveal nonreciprocity in the vortex-creep regime, where finite voltages arise due to the two-dimensional nature of superconductivity. Furthermore, our 2D film demonstrates abrupt voltage jumps, influenced by both the current flow direction and the transverse magnetic field direction. This behavior resembles that of 3D materials but, in this case, is driven by the vortex-flow instability, as illustrated by voltage controlled S-shaped I-V curves. These results underscore the pivotal role of vortex dynamics in SDE and provide new insights into the interplay between symmetry breaking and two-dimensionality in topological insulator/superconductor systems.
Superconductivity (cond-mat.supr-con)
24 pages, 4 figures and 1 extended figure, and supplemental material
Combined effects of particle geometry and applied vibrations on the mechanics and strength of entangled materials
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
Saeed Pezeshki, Francois Barthelat
Entangled materials offer attractive structural features including tensile strength and large deformations, combined with infinite assembly and disassembly capabilities. How the geometry of individual particles governs entanglement, and in turn translates into macroscopic structural properties, provides a rich landscape in terms of mechanics and offers intriguing possibilities in terms of structural design. Despite this potential, there are major knowledge gaps on the entanglement mechanisms and how they can generate strength. In particular, vibrations are known to have strong effects on entanglement and disentanglement but the exact mechanisms underlying these observations are unknown. In this report we present tensile tests and discrete element method (DEM) simulations on bundles of entangled staple-like particles that capture the combined effects of particle geometry and vibrations on local entanglement, tensile force chains and strength. We show that standard steel staples with $ \theta = 90^\circ$ crown-leg angle initially entangle better than $ \theta = 20^\circ$ modified staples because of their more “open” geometry. However, as vibrations are applied entanglement increase faster in $ \theta = 20^\circ$ bundles, so that they develop strong and stable tensile force chains, producing bundles which are almost ten times stronger than $ \theta = 90^\circ$ bundles. Both tensile strength and entanglement density increase with vibrations and also with deformations, up to a steady state value. At that point the rate of entanglement equals the rate of disentanglement, and each of these rates remains relatively high. Finally, we show that vibration can be used as a manipulation strategy to either entangle or disentangle staple-like entangled granular materials, with confinement playing a significant role in determining whether vibration promotes entanglement or disentanglement.
Soft Condensed Matter (cond-mat.soft)
27 pages, 12 Figures
Nitrogen-Triggered Amorphization Enables High-Performance Solid-State Electrolytes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Bolong Hong, Lei Gao, Bingkai Zhang, Pengfei Nan, Ruishan Zhang, Yuhang Li, Zhihao Lei, Ming Liu, Jing Wu, Longbang Di, Haijin Ni, Songbai Han, Jinlong Zhu
Amorphous solid-state electrolytes (SSEs) hold great promise for advancing the application of all-solid-state batteries (ASSBs), owing to their favorable ionic conductivity, structural tunability, and promising electrochemical performance. However, the absence of universal design principles for amorphous SSEs limits their development. By fundamentally re-evaluating the amorphization-forming ability of amorphous SSE systems, this study establishes a nitrogen-driven universal strategy to convert diverse metal chlorides into amorphous xLi3N-MCly (0.3 < 3x < 1.9; M denotes a metal element; 2 < y < 5) SSE. Nitrogen synergistically disrupts crystalline order via distorted coordination polyhedra and N-bridged networks, while dynamic bond reorganization enables rapid Li+ migration, achieving ionic conductivity of 2.02 mS cm-1 for 0.533Li3N-HfCl4 at 25 °C. Structural-property relationships reveal that high charge density and bridging capability of N3- enhance network disorder, shorten metal coordinating atom distances, and optimize Li+ diffusion pathway connectivity. ASSBs employing 0.533Li3N-HfCl4 retain 81.87% capacity after 2000 cycles at 1000 mA g-1 with high cathode loading (6.24 mg cm-2), demonstrating engineering viability. This work provides a paradigm for rational design of high-performance amorphous SSEs.
Materials Science (cond-mat.mtrl-sci)
31 pages, 5 figures
Relationship among Structural, Disordered, Magnetism and Band Topology in MnSb2Te4(Sb2Te3)n Family
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Ming Xi, Yuchong Zhang, Wenju Zhou, Famin Chen, Donghan Jia, Huiyang Gou, Tian Qian, Hechang Lei
Interplay between topology and magnetism induces various exotic quantum phenomena, with magnetic topological insulators (MTIs) serving as a prominent example due to their ability to host the quantum anomalous Hall effect (QAHE). However, the realization of QAHE at higher temperature approaching magnetic-transition-temperature remains a significant challenge, primarily due to the scarcity of suitable material platforms and limited understanding of the intricate relationships between band topology, magnetism, and defects. Here, we report a comprehensive investigation of MnSb2Te4(Sb2Te3)n (n = 0 - 5) single crystals, including the discovery of novel MnSb8Te13 pure phase. Experimental measurements confirm that MnSb8Te13 exhibits ferromagnetism and features topologically nontrivial electronic structures, characterized by a Dirac point located further from the conduction band and a possible larger bulk gap compared to MnBi2Te4(Bi2Te3)n (n = 0 - 3). Moreover, we systematically analyze the relationship between structure, magnetism, topology, and disorder within Mn(Sb, Bi)2Te4((Sb, Bi)2Te3)n family. Present work will shed light on the exploration of potential platforms capable of achieving QAHE near magnetic transition temperature, offering new directions for advancing topological quantum materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
26 pages, 5 figures
J. Phys. Chem. Lett. 16, 9507-9516 (2025)
Ambient-Stable Transfer-Free Graphdiyne Wafers with Superhigh Hole Mobility at Room Temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Beining Ma, Jianyuan Qi, Xinghai Shen
Graphdiyne (GDY) is recognized as a compelling candidate for the fabrication of next-generation high-speed low-energy electronic devices due to its inherent p-type semiconductor characteristics. However, the development of GDY for applications in field-effect transistors (FETs), complementary metal-oxide-semiconductor (CMOS), and logic devices remains constrained by the relatively low carrier mobility reported in current experimental studies. Herein, the synthesis of layer-controlled hydrogen-substituted graphdiyne (HsGDY) films directly on silicon substrates under a supercritical CO2 atmosphere is reported, along with the fabrication of these films into HsGDY-based FETs. The transfer-free growth strategy eliminates performance degradation caused by post-synthesis transfer processes. The resulting HsGDY FETs exhibit a remarkable hole mobility of up to 3800 cm2 V-1 s-1 at room-temperature, which is an order of magnitude higher than that of most p-type semiconductors. The synthesis of transfer-free HsGDY wafers provides a new strategy for resolving the carrier mobility mismatch between p-channel and n-channel two-dimensional metal-oxide-semiconductor devices.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Multiscale Magnetic Correlations in La2Mn2-xNixO6: Role of Crystal Structure in Double Perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
A. K. Bera, K. S. Chikara, B. Saha, S. M. Yusuf, Mohd. Nasir, S. Sen
The magnetic correlations in double perovskites La2Mn2-xNixO6 (x = 0.5, 0.75, 1.0, 1.25 and 1.5) have been systematically investigated across macroscopic, mesoscopic, and microscopic length scales using temperature-dependent bulk DC magnetization, neutron depolarization, and neutron powder diffraction measurements, respectivitly. The magnetic properties evolve from a long-range ferromagnetic (FM) order to a cluster ferromagnetic or spin-glass (FM or SG) behavior as the Ni concentration increases. This evolution is directly linked to changes in the crystal structure, transitioning from pure orthorhombic (x=0.5) to mixed orthorhombic and monoclinic (x=0.75-1.0), and eventually to mixed trigonal and monoclinic symmetries (x=1.25-1.5). Ni substitution enhances the magnetic ordering temperature from 170 K (x=0.5) to 280 K (x=1.0), but this is accompanied by a reduction in both magnetization and ordered magnetic moment. Beyond x=1.0, any long-range magnetic ordering is absent. Additionally, all compositions exhibit a reentrant spin-glass-like phase at low temperatures (below about 50 K). Neutron diffraction analysis confirms that long-range FM order occurs only in the orthorhombic phase, while the monoclinic and trigonal phases lack such magnetic ordering. The temperature-dependent magnetic correlations are closely connected to variations in crystal structural parameters, including lattice constants and unit cell volume. The electrical conductivity behavior, following the variable range hopping (VRH) model, highlights the role of multivalence Mn and Ni ions on the electrical properties. This study elucidates the microscopic mechanisms behind the tunable magnetic and electrical properties of La2Mn2-xNixO6, offering valuable insights for the design of advanced materials for spintronic applications.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
33 pages, 8 figures, 2 tables, Phys. Rev. B (accepted)
Phys. Rev. B (2025)
Quantum many-body analysis of a spin-2 bosons with two-body inelastic decay
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-10-14 20:00 EDT
Takeshi Takahashi, Hiroki Saito
Bose-Einstein condensates (BECs) of $ ^{87}\textrm{Rb}$ atoms with a hyperfine spin of 2 are open quantum systems, where the atoms are lost through two-body inelastic collisions. In this dissipation process, a collision channel with total spin of 4 is forbidden by angular momentum conservation, which results in magnetization of the atoms remaining in the condensate. Here, we investigate the quantum many-body properties of spin-2 bosons that undergo two-body atomic loss. We show that the system finally reaches a steady state, which is a mixture of the states with maximum total spins. In addition, we find that a non-classical steady state can be obtained by quenching the quadratic Zeeman coefficient.
Quantum Gases (cond-mat.quant-gas)
8 pages, 2 figures
Interplay of choice and topology in percolation on mediation-driven attachment networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-14 20:00 EDT
Nilomber Roy, M. M. B. Sheraj, M. K. Hassan
We investigate bond percolation on mediation-driven attachment (MDA) networks under the generalized Achlioptas process, where $ M>1$ candidate bonds are sampled and the one that minimizes the resulting cluster size is selected the best-of-$ M$ rule. This framework offers a systematic approach to investigate how network topology and choice mechanisms jointly shape percolation behavior. We analyze the effects of the degree exponent $ \omega$ and the choice parameter $ M$ on the critical point $ t_c$ and the critical exponents ($ \beta,\alpha,\gamma$ ), which define universality classes and obey the Rushbrooke inequality $ \alpha + 2\beta + \gamma \geq 2$ . Using entropy, the order parameter, and their derivatives (representing specific heat and susceptibility respectively), we show that both $ t_c$ and the universality class depend only weakly on $ \omega$ but strongly on $ M$ , while the Rushbrooke inequality remains valid throughout. For $ M=2$ , the order parameter varies continuously without a clear order-disorder transition. By contrast, $ M=3$ and $ M=4$ display explosive percolation that still corresponds to a continuous phase transition, with $ M=4$ producing a significantly sharper and clearer order-disorder transition. This sharpening is traced to an enhanced powder-keg effect at larger $ M$ , underscoring the entropic origin of explosive percolation.
Statistical Mechanics (cond-mat.stat-mech), Physics and Society (physics.soc-ph)
11 pages, 6 captioned figures
Hybrid Quantum Systems: Coupling Single-Molecule Magnet Qudits with Industrial Silicon Spin Qubits
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Daniel Schroller, Daniel Sitter, Thomas Koch, Viktor Adam, Noah Glaeser, Clement Godfrin, Stefan Kubicek, Julien Jussot, Roger Loo, Yosuke Shimura, Danny Wan, Yaorong Chen, Mario Ruben, Kristiaan De Greve, Wolfgang Wernsdorfer
Molecular spin qudits offer an attractive platform for quantum memory, combining long coherence times with rich multi-level spin structures. Terbium bis(phthalocyaninato) (TbPc$ _2$ ) exemplifies such systems, with demonstrated quantum control and chemical reproducibility. In hybrid quantum architectures, TbPc$ _2$ can act as the primary memory element, with semiconductor qubits providing scalable readout and coupling. Here we present a step toward such a hybrid system: using an industrially manufactured silicon metal-oxide-semiconductor (SiMOS) spin qubit to detect electronic spin transitions of an ensemble of TbPc$ _2$ molecules. The readout is based on a compact and robust protocol that applies a microwave pulse while all gate voltages defining the qubit are held at a fixed operating point. This protocol, which combines simultaneous Rapid adiabatic Passage and Spin- Selective tunneling (RPSS), enables high-contrast resonance detection and avoids repeated $ \pi$ -pulse recalibration common in decoupling schemes. By demonstrating ensemble detection, we establish a foundation for integrating molecular quantum memories with industrial qubit platforms and mark an important step toward single-molecule hybrid quantum technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Manipulating the metal-insulator transitions in correlated vanadium dioxide through bandwidth and band-filling control
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Xiaohui Yao, Jiahui Ji, Xuanchi Zhou
The metal-insulator transition (MIT) in correlated oxide systems opens up a new paradigm to trigger the abruption in multiple physical functionalities, enabling the possibility in unlocking exotic quantum states beyond conventional phase diagram. Nevertheless, the critical challenge for practical device implementation lies in achieving the precise control over the MIT behavior of correlated system across a broad temperature range, ensuring the operational adaptability in diverse environments. Herein, correlated vanadium dioxide (VO2) serves as a model system to demonstrate effective modulations on the MIT functionality through bandwidth and band-filling control. Leveraging the lattice mismatching between RuO2 buffer layer and TiO2 substrate, the in-plane tensile strain states in VO2 films can be continuously adjusted by simply altering the thickness of buffer layer, leading to a tunable MIT property over a wide range exceeding 20 K. Beyond that, proton evolution is unveiled to drive the structural transformation of VO2, with a pronounced strain dependence, which is accompanied by hydrogenation-triggered collective carrier delocalization through hydrogen-related band filling in t2g band. The present work establishes an enticing platform for tailoring the MIT properties in correlated electron systems, paving the way for the rational design in exotic electronic phases and physical phenomena.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Atomic bonding in equilibrium single-component melts. The cases of arsenic, antimony and bismuth
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Artem A. Tsygankov, Bulat N. Galimzyanov, Anatolii V. Mokshin
In liquid pnictogens, quasi-stable structures can be formed near melting temperature. The nature of their stability does not have the unified point of view. In the present work, the task of determining the degree of atomic bonding in these structures is solved using the Crystal Orbital Hamilton Population (COHP) method. The original results of ab-initio simulation of arsenic, antimony and bismuth melts near their melting temperatures are used. It is shown that the features of the electron interaction at the level of $ p$ -orbitals determine the characteristic bond lengths and angles between atoms. It has been established that the stability of structures decreases according to a power law with an increase in the atomic mass of a chemical element and the number of atoms in the structure. The obtained results clarify the understanding the mechanisms of formation of quasi-stable structures in pnictogen melts from first principles.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
25 pages, 6 figures, 2 tables
Journal of Non-Crystalline Solids 668, 123791 (2025)
Scaling of Magnetic Domain Walls in Perpendicular Magnetic Anisotropy Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Guowen Gong, Changmin Xiong, Lijun Zhu
Magnetic domain walls play a critical role in the nanoscale evolution of magnetic devices. Despite the early efforts, a complete understanding of the micromagnetic evolution of the width and the type of magnetic domain walls has still remained missing. Here, we report a combined analytical and micromagnetic simulation study and establish the scaling of the magnetic domains as a function of the exchange stiffness (A), uniaxial perpendicular magnetic anisotropy (Ku), saturation magnetization (Ms), and Dzyaloshinskii-Moriya interaction (DMI), and shape anisotropy of the magnetic device. We find that the width of both Bloch and Neel walls scales excellently with the analytical prediction. The DMI is found to have little influence on the domain wall width but strongly affect the type of the domain wall. The domain wall has a Bloch configuration at zero DMI and gradually transitions to Neel configuration upon increase of the DMI. The shape anisotropy of the magnetic domain wall also affects the domain wall width. These results have established a comprehensive, conclusive understanding of the magnetic domain walls within spintronics devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Localization Transition on Random Graphs with Chiral and Bogoliubov-de Gennes Symmetry Classes
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-10-14 20:00 EDT
We studied single-particle Anderson localization in ensembles of graphs that correspond to chiral and Bogoliubov-de Gennes (BdG) symmetry classes. For a random biregular bipartite graph with chiral symmetry, the density of states was found using the cavity approach. Calculating the fractal dimension shows the effects of disordered zero modes. For Bogoliubov-de Gennes ensembles with an underlying random regular graph (RRG), the density of states was calculated both numerically and analytically. The ensembles BdG-RRG with symmetry-conserving diagonal disorder in the delocalized phase have a smaller fractal dimension compared to the usual RRG.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
13 pages, 2 figures
Vortex matter and strong pinning in underdoped PrFeAs(O,F) with atomic-sized defects
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
Andrey V. Sadakov, Vladimir A. Vlasenko, A.Yu. Levakhova, I.V. Zhuvagin, E.M. Fomina, V.A. Prudkoglyad, A.Y. Tsvetkov, A.S. Usoltsev, N. D. Zhigadlo
We present a comprehensive investigation of the field-dependent critical current density and pinning force, combined with a detailed analysis of the nanostructural defect landscape in single crystal of underdoped PrFeAs(O,F) superconductor. Our study demonstrates that for both in-plane and out-of-plane magnetic field orientations critical current density exhibits a strong pinning regime in intermediate fields across the entire temperature range. The dominant contribution to pinning originates from oxygen-to-fluorine substitutional defects, oxygen vacancies, which all act as point defects via a quasiparticle mean free path fluctuation mechanism. Scanning transmission electron microscope studies did not reveal any volume or surface defect types within the lattice.
Superconductivity (cond-mat.supr-con)
A continued fraction approximation for the effective elasticity tensor of two-dimensional polycrystals as a function of the crystal elasticity tensor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
For two-dimensional polycrystals the effective elasticity tensor $ C_\ast$ as a function $ C_\ast(C_0)$ of the elasticity tensor $ C_0$ of the constituent crystal is considered. It is shown that this function can be approximated by one with a continued fraction expansion resembling that associated with a class of microstructure known as sequential laminates. These are hierarchical microstructures defined inductively. Rank 0 sequential laminates are simply rotations of the pure crystal. Rank $ j$ sequential laminates are obtained by laminating together, on a length scale much larger that the existing microstructure and with interfaces perpendicular to some direction $ n_j$ , rank $ j-1$ sequential laminates with a rotation of the pure crystal. The continued fraction approximation for arbitrary polycrystal microstructures typically takes a more general form than that of sequential laminates, but has some free parameters. It is an open question as to whether these free parameters can always be adjusted so the continued fraction approximation matches exactly that of a sequential laminate. If so, one would have established that the elastic response of two-dimensional polycrystals can always be mimicked by that of sequential laminates. Our analysis carries over to the more general case where the strain is replaced by a field $ E(x)$ that is the gradient of a vector potential $ u(x)$ , i.e. $ E=\nabla u$ and the stress is replaced by a matrix valued field $ J(x)$ that need not be symmetric but has zero divergence $ \nabla\cdot J=0$ . The tensor $ L(x)$ entering the constitutive relation $ J=L E$ is locally a rotation of the tensor $ L_0$ of the pure crystal that need not have any special symmetries and has 16 independent tensor elements.
Materials Science (cond-mat.mtrl-sci), Mathematical Physics (math-ph), Analysis of PDEs (math.AP)
33 Pages and 3 Figures
Pure and Applied Functional Analysis, Volume 10, Number 1, 59-89, 2025
Defect-driven incoherent skin localization
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-10-14 20:00 EDT
Emmanouil T. Kokkinakis, Konstantinos G. Makris, Eleftherios N. Economou
The process of dephasing during wave evolution has traditionally been viewed as an obstacle to localization, leading to diffusion even in strongly disordered Hermitian lattices. In contrast, here we demonstrate how the interplay of dephasing with non-Hermitian defects can be harnessed to engineer wave localization. Specifically, we identify a novel dynamical localization phenomenon characterized by wavefunction accumulation at the lattice’s boundary due solely to dephasing, despite globally reciprocal couplings. Furthermore, we study the incoherent skin effect arising from coupling asymmetry, and investigate the interplay between these antagonistic localization mechanisms. By reframing dephasing from a hindrance into a tool, this study overturns established paradigms of wave localization and paves the way for novel approaches to controlling localization phenomena in non-Hermitian physics.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Optics (physics.optics), Quantum Physics (quant-ph)
7 pages, 4 figures
Roles of Electrically Excited Magnons in Unidirectional Magnetoresistance of Metallic Magnetic Bilayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Shashank Gupta, Steven S.-L. Zhang
Unidirectional magnetoresistance (UMR) in metallic bilayers arises from nonlinear spin-charge transport mediated by broken time-reversal and inversion symmetries, yet the role of magnons remains unsettled. We develop a theoretical framework that incorporates coupled electron-magnon dynamics, revealing cross diffusion and spin-angular-momentum transfer between the two subsystems, which renormalize the characteristic electron and magnon spin-diffusion lengths. We show that nonequilibrium magnons, indirectly excited by the electric field, can suppress UMR by absorbing spin angular momentum from conduction electrons. We also analyze the magnetic-field, thickness, and temperature dependencies and identify distinct features that constitute experimental fingerprints of magnonic contributions to UMR in metallic bilayers, providing qualitative to semiquantitative guidance for elucidating the underlying physical mechanisms.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 6 figures
Atomic-Scale Origins of Oxidation Resistance in Amorphous Boron Nitride
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Onurcan Kaya (1, 2 and 3), Qiushi Deng (4), Thomas Souvignet (5), Catherine Marichy (5), Catherine Journet (5), Ivan Cole (4), Stephan Roche (1 and 6) ((1) Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Barcelona, Spain, (2) School of Engineering, RMIT University, Melbourne, Australia, (3) Department of Electronic Engineering, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain, (4) School of Engineering, The Australian National University, Canberra, Australia, (5) Université Claude Bernard Lyon 1, CNRS, LMI UMR 5615, Villeurbanne, France, (6) ICREA, Barcelona, Spain)
Amorphous boron nitride (\textrm{$ \alpha$ }-BN) is a promising ultrathin barrier for nanoelectronics, yet the atomistic mechanisms governing its chemical stability remain poorly understood. Here, we investigate the structure-property relationship that dictates the oxidation of \textrm{$ \alpha$ }-BN using a combination of machine-learning molecular dynamics simulations and angle-resolved X-ray photoelectron spectroscopy. The simulations reveal that the film structure, controlled by synthesis conditions, is the critical factor determining oxidation resistance. Dense, chemically ordered networks with a high fraction of B-N bonds effectively resist oxidation by confining it to the surface, whereas porous, defect-rich structures with abundant homonuclear B-B and N-N bonds permit oxygen penetration and undergo extensive bulk degradation. These computational findings are consistent with experimental trends observed in \textrm{$ \alpha$ }-BN films grown by chemical vapour deposition. XPS analysis shows that a film grown at a higher temperature develops a more ordered structure with a B/N ratio nearer to stoichiometric and exhibits superior resistance to surface oxidation compared to its more defective, lower-temperature counterpart. Together, these results demonstrate that the oxidation resistance of \textrm{$ \alpha$ }-BN is a tunable property directly linked to its atomic-scale morphology, providing a clear framework for engineering chemically robust dielectric barriers for future nanoelectronic applications.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
29 pages, 8 figures
Osmotic forces modify lipid membrane fluctuations
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
In hydrodynamic descriptions of lipid bilayers, the membrane is often approximated as being impermeable to the surrounding, solute-containing fluid. However, biological and in vitro lipid membranes are influenced by their permeability and the resultant osmotic forces – whose effects remain poorly understood. Here, we study the dynamics of a fluctuating, planar lipid membrane that is ideally selective: fluid can pass through it, while the electrically-neutral solutes cannot. We find that the canonical membrane relaxation mode, in which internal membrane forces are balanced by fluid drag, no longer exists over all wavenumbers. Rather, this mode only exists when it is slower than solute diffusion – corresponding to a finite range of wavenumbers. The well-known equipartition result quantifying the size of membrane undulations due to thermal perturbations is consequently limited in its validity to the aforementioned range. Moreover, this range shrinks as the membrane surface tension is increased, and above a critical tension the membrane mode vanishes. Our findings are relevant when interpreting experimental measurements of membrane fluctuations, especially in vesicles at moderate to high tensions.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph), Fluid Dynamics (physics.flu-dyn)
9 pages, 3 figures, code repository at this https URL
Ferromagnetic Resonance Spectroscopy on the Kagome Magnet MgMn$_6$Sn$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Riju Pal, Kakan Deb, Nitesh Kumar, Bernd Büchner, Alexey Alfonsov, Vladislav Kataev
MgMn$ _6$ Sn$ _6$ is the itinerant ferromagnet on the kagome lattice with high ordering temperature featuring complex electronic properties due to the nontrivial topological electronic band structure, where the spin-orbit coupling (SOC) plays a crucial role. Here, we report a detailed ferromagnetic resonance (FMR) spectroscopic study of MgMn$ _6$ Sn$ _6$ aimed to elucidate and quantify the intrinsic magnetocrystalline anisotropy that is responsible for the alignment of the Mn magnetic moments in the kagome plane. By analyzing the frequency, magnetic field, and temperature dependences of the FMR modes, we have quantified the magnetocrystalline anisotropy energy density that reaches the value of approximately $ 3.5\cdot 10^6$ erg/cm$ ^3$ at $ T = 3$ K and reduces to about $ 1\cdot 10^6$ erg/cm$ ^3$ at $ T = 300$ K. The revealed significantly strong magnetic anisotropy suggests a sizable contribution of the orbital magnetic moment to the spin magnetic moment of Mn, supporting the scenario of the essential role of SOC for the nontrivial electronic properties of MgMn$ _6$ Sn$ _6$ .
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
9 pages, 8 figures
Applied Magnetic Resonance, 2025
Controllable Domain Wall Memories with Magnetic Topological Insulator
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-10-14 20:00 EDT
Domain wall memories have undergone several changes over the years for faster shift, read, and write operations; however, fundamental issues persist due to creating pinning sites topographically along the nanowire. The deformity in notches creates non-uniform pinning strength, leading to multiple faults during shift operation. This study proposes a novel approach to address these challenges and gain greater control over domain manipulation for advanced applications in Boolean and non-Boolean paradigms. Utilizing the magnetic topological insulator (MTI) can create pinning sites without potentially faulty topographical notches made through complex lithography. Moreover, applying an external current enables precise control over the pinning potentials at these sites. Micromagnetic simulations validate the effectiveness of MTI-based pinning sites, showcasing their potential for future applications. Our approach introduces an alternative method for creating pinning sites by cross-architecture of ferromagnetic nanowires and MTI nanobars, inducing exchange interaction at their intersection points. This method offers simplicity of fabrication and enables control over the pinning strength by external current.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Applied Physics (physics.app-ph)
Breakdown of the Wiedemann-Franz law in an interacting quantum Hall metamaterial
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Patrice Roche, Carles Altimiras, François D. Parmentier, Olivier Maillet
Quantum heat transport by electrons in ballistic channels is usually well-described in the Landauer-Büttiker framework, which fails when introducing strong Coulomb interactions. We theoretically show that a chain of small metallic dots where charge cannot accumulate, connected by chiral ballistic channels, conducts heat better than charge. We relate this feature to the competition between heat diffusion by neutral excitations and Coulomb interactions in the chain, which defines a temperature gradient over a finite characteristic length. We show that the Lorenz ratio can be arbitrarily large, scaling as the square root of the chain’s length, which suggests new approaches for heat manipulation in mesoscopic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages (5 main text/refs + 5 supplemental material)
Electric Polarization-Driven Modulation of Fe Adatoms on Ferroelectric $α$-In$_2$Se$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Monirul Shaikh, Aleksander L. Wysocki
The interplay among structural, electronic, and magnetic properties of Fe adatoms on the surface of two-dimensional ferroelectric {\alpha}-In$ _2$ Se$ _3$ is investigated using first-principles electronic structure calculations, with a focus on how these properties are modulated by the direction of the electric polarization of the substrate. We identify two competing adsorption sites for Fe adatoms, whose relative stability depends on the adatom concentration and can be reversed by switching the electric polarization of {\alpha}-In$ _2$ Se$ _3$ . The calculated energy barrier for thermally activated hopping between these sites is approximately 0.4 eV, corresponding to a blocking temperature of around 100 K. The hybridization between Fe and In$ _2$ Se$ _3$ orbitals strongly depends on the adsorption site and polarization direction, driven by variations in the local adatom geometry. As a result, the electronic configuration of adatom, magnetic moment, and magnetic anisotropy exhibit a pronounced site dependence and can be effectively modulated by switching the electric polarization of the In$ _2$ Se$ _3$ layer. In particular, at higher adatom concentrations, an exceptionally large perpendicular magnetic anisotropy, exceeding 200 meV per Fe atom, emerges for one polarization direction, but is largely diminished when the polarization is reversed. These findings indicate that ferroelectric substrates offer a promising route for voltage-controlled tuning of magnetic adatom properties via reversible polarization switching.
Materials Science (cond-mat.mtrl-sci)
Proof of the exact diffusion constant via first passage time in quasi-periodic potentials
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-14 20:00 EDT
Brownian motion in terms of Lifson and Jackson (LJ) formula has been widely explored in periodic systems and it has been believed for a long time that the LJ formula only applies to periodic potentials. Recently we show that for the following Brownian motion $ \gamma \dot{x} = -U’(x) + \xi$ , where $ U(x)$ is the quasi-periodic potential, the effective diffusion constant can still be described by the LJ formula $ D^\ast = D/(\langle \exp(\beta U)\rangle \langle \exp(-\beta U)\rangle)$ , where the average is redefined as $ \langle \exp(\beta U)\rangle = \lim_{L\rightarrow \infty} L^{-1} \int_0^L \exp(\beta U(x))dx$ . In this manuscript we prove this result exactly using the mean first passage time $ \tau(x)$ , with boundary conditions $ \tau(\pm L) = 0$ , and show that the effective diffusion constant can be determined using $ D^\ast =\lim_{L \rightarrow \infty} L^2/(2\tau(0))$ , where $ \pm L$ is the two positions of the absorbing boundary. We exactly solve the equation of motion of $ \tau(x)$ and obtain the above result with the aid of Jacobi-Anger expansion method. Our result can be generalized to the other potentials and even higher dimensions, which can greatly broaden our understanding of Brownian motion in more general circumstances. The requirement for a well-defined effective diffusion constant $ D^\ast$ in more general potentials is also discussed.
Statistical Mechanics (cond-mat.stat-mech)
5 pages, zero figure
Growth control of highly textured Bi2Te3 thin films by pulsed laser deposition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Damian Brzozowski, Yu Liu, Karola Neeleman, Magnus Nord, Ingrid G. Hallsteinsen
Two-dimensional materials have attracted growing interest due to their unique electronic properties and potential applications in spintronics. Interfacing strongly spin-orbit-coupled chalcogenides with functional oxides such as perovskites has a particularly high potential. In this work, highly textured Bi2Te3 thin films were deposited on (111) oriented SrTiO3 by pulsed laser deposition. We show that, by careful selection of the temperature and pressure of growth, the film’s stoichiometry can be manipulated between direct stoichiometry transfer from the target and tellurium-deficient phases. Optimized pulsed laser deposition enables the growth of films with coalesced, faceted grains with grain sizes reaching up to 430 nm, while preserving crystalline quality comparable to that of molecular-beam-epitaxy-grown films. We show striking differences arising from tuning the laser’s pulsing frequency and fluence, which lead to changes in surface roughness, the film’s porosity, and grain boundaries, as well as grain shape. Analysis of cross-sectional transmission electron microscopy images reveals a sharp substrate-film interface without atomic intermixing and without the formation of amorphous intermediate layers. The results demonstrate that pulsed laser deposition is a viable method for producing high-quality Bi2Te3 thin films and opens the door to the integration of chalcogenides with perovskites with this growth technique.
Materials Science (cond-mat.mtrl-sci)
19 pages, 6 figures + supplementary. Under review at ACS crystal growth and design
Anisotropic Strain Engineering in La0.7Sr0.3MnO3/LaFeO3 Superlattice: Structural Relaxation and Domain Formation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Yu Liu, Thea Marie Dale, Emma van der Minne, Susanne Boucher, Romar Avila, Christoph Klewe, Gertjan Koster, Magnus Nord, Mari-Ann Einarsrud, Ingrid Hallsteinsen
Anisotropic strain engineering in epitaxial oxide films provides new opportunities to control the antiferromagnetic and structural properties crucial for advancements of antiferromagnetic spintronics. Here we report on a (La0.7Sr0.3MnO3/LaFeO3)4 superlattice grown on (101)o DyScO3 substrate which imposes significant anisotropic in-plane strain. Reciprocal space mapping reveals selective strain relaxation along the tensile in-plane [010]o axis, while compression along the perpendicular in-plane [-101]o axis remains strained. Scanning precession electron diffraction and higher-order Laue zone analysis show that the relaxation is accommodated by structural domain formation in the LaFeO3 layers, initiating from the second bilayer and propagating out-of-plane. These domains minimise structural defects and correlate with the substrate step edges. X-ray magnetic dichroism measurements reveal bulk-like in-plane antiferromagnetic order with polydomain signature as previously reported. Our findings reveal the presence of structural domains coexisting with antiferromagnetic polydomain states, showing a strain-domain-magnetism relationship that provides insights for applications of strain engineering in spintronics applications.
Materials Science (cond-mat.mtrl-sci)
17 pages, 6 figures + supplementary - under review at Quantum Materials npj
Resolving the Structural Duality of Graphene Grain Boundaries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Haojie Guo, Emiliano Ventura-Macías, Mariano D. Jiménez-Sánchez, Nicoleta Nicoara, Pierre Mallet, Jean-Yves Veuillen, Vincent T. Renard, Antonio J. Martínez-Galera, Pablo Pou, Julio Gómez-Herrero, Rubén Pérez, Iván Brihuega
Grain boundaries (GBs) are ubiquitous in large-scale graphene samples, playing a crucial role in their overall performance. Due to their complexity, they are usually investigated as model structures, under the assumption of a fully relaxed interface. Here, we present cantilever-based non-contact atomic force microscopy (ncAFM) as a suitable technique to resolve, atom by atom, the complete structure of these linear defects. Our experimental findings reveal a richer scenario than expected, with the coexistence of energetically stable and metastable graphene GBs. Although both GBs are structurally composed of pentagonal and heptagonal like rings, they can be differentiated by the irregular geometric shapes present in the metastable boundaries. Theoretical modeling and simulated ncAFM images, accounting for the experimental data, show that metastable GBs form under compressive uniaxial strain and exhibit vertical corrugation, whereas stable GBs remain in a fully relaxed, flat configuration. By locally introducing energy with the AFM tip, we show the possibility to manipulate the metastable GBs, driving them toward their minimum energy configuration. Notably, our high-resolution ncAFM images reveal a clear dichotomy: while the structural distortions of metastable grain boundaries are confined to just a few atoms, their impact on graphene’s properties extends over significantly larger length scales.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Accepted version of the article to appear in Advanced Materials (Wiley-VCH)
Constructing a Nanopipette-based DNA Electro-Mechanical Device
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Cengiz J. Khan, Oliver J. Irving, Rand A. Al-Waqfi, Giorgio Ferrari, Tim Albrecht
Solid-state nanopore and nanopipette sensors are powerful devices for the detection, quantification and structural analysis of biopolymers such as DNA and proteins, especially in carrier-enhanced resistive-pulse sensing. However, hundreds of different molecules typically need to be sampled from solution and analysed to obtain statistically robust information. This limits the applicability of such sensors and complicates associated workflows. Here, we present a new strategy to trap DNA structures in the sensing region of a nanopipette through end functionalisation and nanoparticle capping. We develop a robust set of descriptors to characterise the insertion and presence of nanoparticle-DNA constructs in the nanopipette tip and, furthermore, show that they remain mobile and responsive to external electric fields over extended periods of time. This allows for repeated readout of the same DNA structure and could enable new applications for such sensors, for example in flow and in confined environments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
38 pages, 13 figures
A ferroelectric junction transistor memory made from switchable van der Waals p-n heterojunctions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Baoyu Wang, Lingrui Zou, Tao Wang, Lijun Xu, Zexin Dong, Xin He, Shangui Lan, Yinchang Ma, Meng Tang, Maolin Chen, Chen Liu, Zhengdong Luo, Lijie Zhang, Zhenhua Wu, Yan Liu, Genquan Han, Bin Yu, Xixiang Zhang, Fei Xue, Kai Chang
Van der Waals (vdW) p-n heterojunctions are important building blocks for advanced electronics and optoelectronics, in which high-quality heterojunctions essentially determine device performances or functionalities. Creating tunable depletion regions with substantially suppressed leakage currents presents huge challenges, but is crucial for heterojunction applications. Here, by using band-aligned p-type SnSe and n-type ferroelectric {\alpha}-In2Se3 as a model, we report near-ideal multifunctional vdW p-n heterojunctions with small reverse leakage currents (0.1 pA) and a desired diode ideality factor (1.95). As-fabricated junction transistors exhibit superior performance, such as a high on/off ratio of over 105. Importantly, we realize ferroelectric-tuned band alignment with a giant barrier modulation of 900 meV. Based on such tunable heterojunctions, we propose and demonstrate a fundamental different device termed ferroelectric junction field-effect transistor memory, which shows large memory windows (1.8 V), ultrafast speed (100 ns), high operation temperature (393 K), and low cycle-to-cycle variation (2 %). Additionally, the reliable synaptic characteristics of these memory devices promise low-power neuromorphic computing. Our work provides a new device platform with switchable memory heterojunctions, applicable to high performance brain-inspired electronics and optoelectronics.
Materials Science (cond-mat.mtrl-sci)
Time domain braiding of anyons revealed through a nonequilibrium fluctuation dissipation theorem
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
We derive a novel fluctuation–dissipation theorem (FDT) valid for nonequilibrium initial states that imprint the braiding of anyons in the time domain. The derivation is carried out within the Unifying Nonequilibrium Perturbative Theory (UNEPT), which applies to both standard reservoir geometries and configurations with one or two quantum point contacts (QPCs) injecting dilute anyonic fluxes. Based on this FDT, we propose complementary methods to determine the time-domain braiding phase. The first method relates the DC backscattering noise to the integral of the current with respect to DC drives, while the second connects the AC current phase shift to the DC noise. The latter provides a particularly robust probe of the statistical angle $ \theta$ , offering an intrinsic calibration and cancelling certain nonuniversal renormalization effects. Specializing to a thermalized Tomonaga–Luttinger liquid (TLL), we further show that in the quantum regime the phase shift enables a direct determination of the scaling dimension $ \delta$ when $ \delta > 1/2$ . These results define experimentally accessible schemes to extract either $ \theta$ or $ \delta$ in minimal single-QPC setups, without relying on interferometry or cross-correlation measurements.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
10 pages, 3 figures
Supercurrent interference and its transfer in a kagome superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
Heng Wu, Houssam el Mrabet Haje, Michiel Dubbelman, Brenden R. Ortiz, Stephen D. Wilson, Mazhar N. Ali, Yaojia Wang
Superconductivity represents a macroscopic quantum state notable for its rich manifestations of electronic coherence and collective behavior. Kagome materials AV3Sb5 (A= K, Cs, Rb) possess cascade intertwined quantum phases including superconductivity, symmetry-breaking charge orders, nematic orders and topological states, making them attractive materials for exploring exotic superconducting states. However, the superconducting properties and the Cooper pairing behaviors have not been fully explored and understood. In this work, by studying both the magnetoresistance and critical current behaviors in KV3Sb5 ring and pristine flakes, we reveal the charge 2e paring in KV3Sb5 although anomalous oscillations with smaller periodicity were observed, and report the intrinsic superconducting phase coherence in KV3Sb5 flakes. The former is demonstrated by the careful verification of the Little-Parks oscillations in differential resistance colormaps, and the latter indicates the existence of superconducting domains in KV3Sb5. Moreover, we observed a special phenomenon: the transfer of supercurrent interference patterns between the superconducting ring and the superconducting flake, which demonstrates the global critical current effect of the superconducting phase coherence. These findings provide new insights into the Cooper pairing behaviors in KV3Sb5 and highlight the importance of global effect of superconducting phase coherence in the understanding of the superconducting behaviors.
Superconductivity (cond-mat.supr-con)
Near room temperature magnetoelectric response and tunable magnetic anisotropy in the two-dimensional magnet 1T-CrTe2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Fengping Li, Bheema Lingam Chittari, Chao Lei, Jeil Jung
Magnets with controllable magnetization and high critical temperature are essential for practical spintronics devices, among which the two-dimensional 1T-CrTe2 stands out because of its high experimental critical temperature up to about 300K down to the single layer limit. By using ab initio density functional theory, we investigate the magnetic properties of monolayer and bilayer 1T-CrTe2 and demonstrate that the magnetic properties, such as the magnetocrystalline anisotropy, critical Curie temperature and magnetizations, can be influenced by strain or electric fields.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Breaking the Sabatier Principle by Dynamic Adsorption-Desorption Decoupling in Electrocatalytic Hydrogen Evolution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Zi-Xuan Yang, Lei Li, Tao Huang, Hui Wan, X.S. Wang, Gui-Fang Huang, Wangyu Hu, Wei-Qing Huang
The Sabatier principle establishes a fundamental trade-off in heterogeneous this http URL the hydrogen evolution reaction (HER), this trade-off is manifested by the coupling of Volmer step, which requires strong hydrogen adsorption, with the Heyrovsky/Tafel step, which favors facile desorption, thus giving rise to the classical volcano relationship and limiting activity even at $ \Delta G=0$ . Here, we demonstrate a ferroelectric platform with dynamic tunability – monolayer GeS$ _2$ decorated with transition metal atoms as a proof-of-concept – where polarization-driven surface electronic reconstruction enables real-time modulation of intermediate binding strength, thereby breaking the Sabatier constraint. Reversible control of hydrogen adsorption allows strong H binding to accelerate the Volmer step, followed by weakened adsorption to promote the Heyrovsky/Tafel this http URL dynamic adsorption-desorption decoupling not only surpasses the volcano limit to achieve unprecedented HER activity, but also establishes a general paradigm for designing adaptive electrocatalysts capable of reconfiguring under operating conditions.
Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures
RKKY interaction in Weyl semimetal nanowires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Rohit Mukherjee, Asutosh Dubey
We investigate the effective couplings induced between localized impurities on the surface of a Weyl semimetal (WSM) nanowire within the framework of Ruderman–Kittel–Kasuya–Yosida (RKKY) theory. The itinerant electrons from the chiral Fermi arc surface states mediate impurity-impurity interaction at low energies. As a result, the spin-momentum locking naturally plays a central role in shaping the spin-spin correlations. We show that the dominant interaction channels have distinct origins: while the azimuthal coupling, $ J_{\phi\phi}$ term arises exclusively from Fermi arc states with identical spin polarization, the couplings $ J_{\mu\nu}$ ($ \mu,\nu = z,r$ ) are governed by Fermi arc states with opposite spin polarizations. Furthermore, we demonstrate that purely surface-mediated contributions exhibit different scaling behavior compared to those involving Fermi arcs and low-energy bulk states. We systematically untangle the contributions from bulk and surface states to the RKKY couplings, using analytical and numerical methods. Our results establish WSM nanowires as a versatile platform for engineering and simulating a broad class of spin models.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 5 Figures; Comments welcome
Weak-anti-localization-to-spin-dependent scattering at a proximity-magnetized heavy metal interface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Hisakazu Matsuki, Guang Yang, Jiahui Xu, Vitaly N. Golovach, Yu He, Jiaxu Li, Alberto Hijano, Niladri Banerjee, Iuliia Alekhina, Nadia Stelmashenko, F. Sebastian Bergeret, Jason W. A. Robinson
A change in a materials electrical resistance with magnetic field (magnetoresistance) results from quantum interference effects and, or spin-dependent transport, depending on materials properties and dimensionality. In disordered conductors, electron interference leads to weak localization or anti-localization; in contrast, ferromagnetic conductors support spin-dependent scattering, leading to giant magnetoresistance (GMR). By varying the thickness of Au between 4 and 28 nm in a EuS/Au/EuS spin-switches, we observe a crossover from weak anti-localization to interfacial GMR. The crossover is related to a magnetic proximity effect in Au due to electron scattering at the insulating EuS interface. The proximity-induced exchange field in Au suppresses weak anti-localization, consistent with Maekawa-Fukuyama theory. With increasing Au thickness, GMR emerges along with spin Hall magnetoresistance. These findings demonstrate spin transport governed by interfacial exchange fields, building a framework for spintronic functionality without metallic magnetism.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Topology and Martensitic Phase Transformations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Triply periodic minimal surfaces (TPMS) are discovered to conform to surfaces of given charge density distributions embedded in crystals [Z. Kristallogr. \textbf{170}, 138 (1985)]. Based on our previous work [Phys. Rev. Mater. \textbf{9}, 073802 (2025)], we discovered that crystals can have surfaces of a given charge density converging to TPMS. We also discovered that end states connected by a martensitic phase transformation should have their corresponding TPMS being topologically equivalent. In this work, we gave an explanation for the topological continuity of a martensitic phase transformation and studied how TPMS indicate whether a non-magnetic crystal can undergo a martensitic phase transformation or not.
Materials Science (cond-mat.mtrl-sci)
Non-unitary Time Evolution via the Chebyshev Expansion Method
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Áron Holló, Dániel Varjas, Cosma Fulga, László Oroszlány, Viktor Könye
The Chebyshev expansion method is a well-established technique for computing the time evolution of quantum states, particularly in Hermitian systems with a bounded spectrum. Here, we show that the applicability of the Chebyshev expansion method extends well beyond this constraint: It remains valid across the entire complex plane and is thus suitable for arbitrary non-Hermitian matrices. We identify that numerical rounding errors are the primary source of errors encountered when applying the method outside the conventional spectral bounds, and they are not caused by fundamental limitations. By carefully selecting the spectral radius and the time step, we show how these errors can be effectively suppressed, enabling accurate time evolution calculations in non-Hermitian systems. We derive an analytic upper bound for the rounding error, which serves as a practical guideline for selecting time steps in numerical simulations. As an application, we illustrate the performance of the method by computing the time evolution of wave packets in the Hatano-Nelson model.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Horizon Europe funding; Non-Hermitian topological systems and their applications for sensors, NHTS 101151049
Near-room-temperature antiferromagnetism in Janus Fe$X$F ($X$ = O, S) monolayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Xixiang Zhang, Busheng Wang, Yanfeng Ge, Yong Liu, Wenhui Wan
Inspired by the recently synthesized hexagonal layered phase of FeF$ _2$ , we studied the magnetic properties of the 1T-FeF$ _2$ monolayer and its Janus Fe$ X$ F ($ X$ = O, S) derivatives by first-principles calculations. Our results confirm that these materials are antiferromagnetic semiconductors, and that anion substitution effectively tunes their material properties: the band gap shifts from 3.37 eV (direct, FeF$ _2$ ) to 2.35 eV (direct, FeOF) and 1.13 eV (indirect, FeSF); the magnetic moment of Fe ions increases; and the Néel temperature ($ T_N$ ) rises dramatically to 248 K (FeSF) and 207 K (FeOF). Janus structures exhibit enhanced magnetic moment and direct AFM coupling. Under compression, $ T_N$ is further optimized to 274 K ($ -2$ % strain, FeSF) and 244 K ($ -5$ % strain, FeOF). Both Janus materials retain their semiconducting nature and direction of easy magnetization axis under $ \pm5$ % strain. This study validates the Janus structure as a viable approach to enhance 2D antiferromagnetism and highlights Fe-based oxyhalides as promising spintronic materials.
Materials Science (cond-mat.mtrl-sci)
Integrable Model of a Superconductor with non-Fermi liquid and Mott Phases
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Santhosh M, Jorge Dukelsky, Gerardo Ortiz
We present and analyze an exactly solvable interacting fermionic pairing model, which features interactions that entangle states at momenta $ \mathbf{k}$ and $ -\mathbf{k}$ . These interactions give rise to novel correlated ground states, leading to a rich phase diagram that includes superconducting, multiple metallic, and Mott-insulating phases. At finite interaction strengths, we observe the emergence of multiple many-body Fermi surfaces, which violate Luttinger’s theorem and challenge the conventional Landau-Fermi liquid paradigm. A distinguishing feature of our model is that it remains quantum integrable, even with the addition of pairing interactions of various symmetries, setting it apart from the Hatsugai-Kohmoto model. Our results provide an analytically tractable framework for studying strong correlation effects that give rise to fractionalized excitations and unconventional superconductivity, offering valuable insights into a broad class of integrable many-body systems.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
25 pages, 12 figures
Ultra-transient grating spectroscopy for visualization of surface acoustics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Tomáš Grabec (1), Pavla Stoklasová (1), Kristýna Repček (1), Jakub Kušnír (1,2), David Mareš (1), Martin Ševčík (1), Petr Sedlák (1), Hanuš Seiner (1) ((1) Institute of Thermomechanics, Czech Academy of Sciences, Prague, (2) Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague)
Ultrasonic wave propagation across material surfaces reveals essential information about the materials’ elastic behavior. The elastodynamic response of the surface is characterized by the Green’s function that fully captures all its direction-dependent and frequency-dependent features. Here we present the first direct experimental visualization of the Green’s function, including all its complex details resulting from elastic anisotropy. We achieve this visualization using a dedicated modification of transient grating spectroscopy (TGS), which is a method otherwise well established for measuring Rayleigh-type surface acoustic waves. To overcome the limitations of conventional TGS, we explore near-field thermoacoustic phenomena occurring within TGS experiments. We reveal that, along with the transient standing-wave patterns that diminish within hundreds of nanoseconds, there also emerge ultra-transient oscillations with lifetimes at least an order of magnitude shorter. These ultra-transient effects enable capturing the surface acoustic response with exceptional detail, and the resulting experimental angular dispersion maps strikingly replicate the theoretical Green’s functions. By utilizing this feature, ultra-transient grating spectroscopy (UTGS) becomes a powerful new tool for detailed contactless characterization of anisotropic solids, opening new pathways for studying single-crystalline materials utilized in diverse modern application fields, including solid-state cooling via the elastocaloric effect, magnetoelastic devices, or nanoscale electromechanical systems.
Materials Science (cond-mat.mtrl-sci)
Manuscript submitted to Nature Communications. Supplementary material is available as ancillary file
Revisiting YH$_9$ Superconductivity and Predicting High-T$_c$ in GdYH$_5$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
The discovery of superconductivity in $ \mathrm{YH_{9}}$ with a critical temperature of approximately $ T_c\sim 243 \ K$ has opened a new window toward room temperature superconductivity. In this work, we employ the lowest order constrained variational method to investigate the thermodynamic and magnetic properties of the $ \mathrm{YH_{9}}$ structure, obtaining results in good agreement with experimental data. % Based on the robustness of the LOCV approach for describing high-$ T_c$ superconductors, we further extend our analysis to the gadolinium-yttrium-hydrogen system across various stoichiometries. The key finding of this study is the prediction of a superconducting phase transition at $ T_c = 223.2\mathrm{K}$ for $ \mathrm{GdYH_{5}}$ under a critical pressure of approximately $ 157\mathrm{GPa}$ . This compound crystallizes in a tetragonal structure with space group $ P4/mmm$ . Moreover, the calculated gap ratio confirms that $ \mathrm{GdYH_{5}}$ is a type-II superconductor with a critical current density suitable for potential industrial applications.
Superconductivity (cond-mat.supr-con)
Approach to zigzag and checkerboard patterns in spatially extended systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-14 20:00 EDT
Manoj C. Warambhe, Prashant M. Gade
Zigzag patterns in one dimension or checkerboard patterns in two dimensions occur in a variety of pattern-forming systems. We introduce an order parameter `phase defect’ to identify this transition and help to recognize the associated universality class on a discrete lattice. In one dimension, if $ x_{i}(t)$ is a variable value at site $ i$ at time $ t$ . We assign spin $ s_i(t)=1$ for $ x_{i}(t)>x_{i-1}(t)$ , $ s_i(t)=-1$ if $ x_{i}(t)<x_{i-1}(t)$ , and $ s_i(t)=0$ if $ x_{i}(t)=x_{i-1}(t)$ . The phase defect $ D(t)$ is defined as $ D(t)={\frac{\sum_{i=1}^N \vert s_i(t)+s_{i-1}(t)\vert} {2N}}$ for a lattice of $ N$ sites with periodic boundary conditions. It is zero for a zigzag pattern. In two dimensions, $ D(t)$ is the sum of row-wise as well as column-wise phase defects and is zero for the checkerboard pattern. The persistence $ P(t)$ is the fraction of sites whose spin value did not change even once till time $ t$ . We find that $ D(t)\sim t^{-\delta}$ and $ P(t)\sim t^{-\theta}$ for the parameter range over which the zigzag or checkerboard pattern is realized. We observe that $ \delta=0.5$ and $ \theta=3/8$ for 1-d coupled logistic maps or Gauss maps, and $ \theta=0.22$ and $ \delta=0.45$ in 2-d logistic or Gauss maps. The exponent $ \theta$ matches with the persistence exponent at zero temperature for the Ising model, and $ \delta$ matches with the exponent for the Ising model at the critical temperature. This power-law decay is observed over a range of parameter values and not just critical point.
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 9 figures
Chaos, Solitons & Fractals, 172, 113510 (2023)
Unveiling the growth mode diagram of GaSe on sapphire
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
M. Bissolo, M. Dembecki, J. Belz, J. Schabesberger, M. Bergmann, P. Avdienko, F. Rauscher, A. S. Ulhe, H. Riedl, K. Volz, J. J. Finley, E. Zallo, G. Koblmüller
The growth of two-dimensional epitaxial materials on industrially relevant substrates is critical for enabling their scalable synthesis and integration into next-generation technologies. Here we present a comprehensive study of the molecular beam epitaxial growth of gallium selenide on 2-inch c-plane sapphire substrates. Using in-situ reflection high-energy electron diffraction (RHEED), in-situ Raman spectroscopy, optical and scanning electron microscopies, we construct a diagram of the gallium selenide growth modes as a function of substrate temperature (530-650 °C) and Se/Ga flux ratio (5-110). The growth mode diagram reveals distinct regimes, including the growth of layered post-transition metal monochalcogenide GaSe with an unstrained in-plane lattice constant of 0.371$ \pm$ 0.001 nm and a partial epitaxial alignment on sapphire. This work demonstrates a RHEED-based pathway for synthesizing gallium selenide of specific phase and morphology, and the construction of a phase diagram for high vapor pressure III-VI compounds that can be applied to a wide range of other metal chalcogenide materials.
Materials Science (cond-mat.mtrl-sci)
Fluidity and morphological stability of an amorphous thin film with radiation-induced defect kinetics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
It is common to model ion-irradiated amorphous thin films as if they were highly viscous fluids. In such models, one is frequently concerned with the ion-enhanced fluidity, a measure of the ability of the free interface to relax surface energy. Motivated by usual fluid dynamics problems, the ion-enhanced fluidity is near-universally treated as a constant throughout the amorphous layer. However, for an irradiated thin film, the fluidity is ultimately caused by radiation-induced defect kinetics within the film, leading to regions with greater or lesser fluidity, and sensitive dependence on ion energy, species, flux, irradiation angle, temperature, and other experimental parameters. Here, we develop and analyze a model of radiation-induced defect kinetics coupled to the continuum equations of a viscous thin film. Using realistic parameter values, we show that defect kinetics can meaningfully alter theoretical predictions of surface relaxation and ion-enhanced fluidity. Implications for aligning theoretical and experimental work, especially for surface nano-patterning of silicon induced by low-energy argon irradiation, are discussed.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Pattern Formation and Solitons (nlin.PS)
Spectral properties of a Non-Hermitian extension of the diluted Wishart ensemble
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-10-14 20:00 EDT
Isaac Pérez Castillo, Edgar Guzmán-González
We develop a theoretical framework based on the cavity and replica methods to analyze the spectral properties of sparse asymmetric correlation matrices of the form $ \boldsymbol{F} = (\boldsymbol{X}\boldsymbol{Y}^\top + \omega \boldsymbol{Y}\boldsymbol{X}^\top)/2T$ , where $ \boldsymbol{X}$ and $ \boldsymbol{Y}$ are adjacency matrices of weighted Erdős–Rényi random graphs. We examine how the spectral density evolves as the asymmetry parameter $ \omega$ varies from $ 0 < \omega < 1$ (nearly symmetric matrices) to $ -1 < \omega \le 0$ (nearly antisymmetric matrices). Analytical predictions are validated through exact numerical diagonalization, showing excellent agreement with theoretical results in the thermodynamic limit.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
22 pages, 2 figures
Electron-hole liquid in biological tissues under ultra high dose rate ionizing radiation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
We develop a quantitative model of ionization processes in biological tissues under Ultra High Dose Rate (UHDR) radiation. The underlying conjecture is that of electron-hole liquid (EHL) forming in water based substances of biological tissues. Unlike the earlier known EHL in semiconductor crystals, the charge carriers here are low mobile due to strong interactions with the background (solvated electrons, etc.); hence, EHL resembling ionic melts. Similar to all ionic systems, the Coulomb coupling makes that EHL energetically favorable that leads to recombination barriers suppressing subsequent structural transformations. In particular, generation of secondary reactive species in such EHL becomes limited translating into reduction of biological damages and tissue sparing effect. We show how these processes are sensitive to the tissue quality and frequency dispersion of the dielectric permittivity. Equations for dose and dose rate defining the sparing thresholds are derived.
Materials Science (cond-mat.mtrl-sci), Biological Physics (physics.bio-ph), Medical Physics (physics.med-ph)
6 pages, 5 figures
Emerging Ferroelectric Domains: Stacking and Rotational Landscape of MoS2 Moire Bilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Anikeya Aditya, Ayu Irie, Nabankur Dasgupta, Rajiv K. Kalia, Aiichiro Nakano, Priya Vashishta
The structures and properties of moire patterns in twisted bilayers of two-dimensional (2D) materials are known to depend sensitively on twist angle, yet their dependence on stacking order remains comparatively underexplored. In this study, we use molecular dynamics simulations to systematically investigate the combined effects of stacking order and rotation in MoS2 bilayers. Beginning from five well-established high-symmetry bilayer stackings, we apply twist angles between 1 and 120 to the top layer, revealing a variety of relaxed moire structures. Our results show that the initial stacking significantly influences the moire domain configurations that emerge at a given twist angle. While all five stacking orders are metastable without twist, they form two moire-equivalent classes- AA/AB and AA’,A’B,AB’, i.e., for a given twist angle, structures within each class relax to the same moire configuration. Specifically, initial AA and AB stackings give rise to triangular ferroelectric domains near 0+/-3, while AA’, A’B, and AB’ stackings produce triangular ferroelectric domains near 60+/-3. At precisely 60 and 120 twists, the bilayers relax to into pure high-symmetry stackings, highlighting the rotational relationships between these configurations and explaining the shift of 60 in the ferroelectric rotational range. These findings demonstrate the critical role of stacking order in governing the rich moire landscapes accessible in twistronic systems.
Materials Science (cond-mat.mtrl-sci)
Quantifying Charge Noise Sources in Quantum Dot Spin Qubits via Impedance Spectroscopy, DLTS, and C-V Analysis
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Tyafur Rahman Pathan, Daryoosh Vashaee
The coherence and fidelity of quantum dot (QD) spin qubits are fundamentally limited by charge noise arising from electrically active trap states at oxide interfaces, heterostructure boundaries, and within the bulk semiconductor. These traps introduce electrostatic fluctuations that couple to the qubit via spin-orbit interactions or charge-sensitive confinement potentials, leading to dephasing and gate errors. In this work, we present a general trap characterization framework for identifying and quantifying the spectral signatures of these trap states using AC impedance spectroscopy, deep-level transient spectroscopy (DLTS), and conventional capacitance-voltage (C-V) analysis. While our case study focuses on strained Ge/SiGe quantum well heterostructures, the approach is broadly applicable to other material systems and qubit types. We demonstrate that each class of traps (oxide interface, quantum well interface, and bulk) exhibits distinct fingerprints across frequency- and time-domain measurements. Oxide traps dominate the low-frequency conductance peaks and appear strongly in Nyquist and transient spectra. QW interface traps, despite being nearly invisible at low densities in conventional C-V and AC impedance analysis, are clearly resolved through multi-exponential decay signatures in time-domain response. Bulk traps contribute to high-frequency admittance and steady-state leakage currents. By correlating each trap type to its characteristic time constant, spatial location, and spectral impact, we provide a diagnostic toolset for disentangling noise sources that degrade qubit performance. This unified methodology bridges traditional defect metrology with emerging qubit noise analysis and enables material- and process-level strategies for coherence optimization in scalable quantum devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Magnetic Field-Enhanced Graphene Superconductivity with Record Pauli-Limit Violation
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
Jixiang Yang, Omid Sharifi Sedeh, Chiho Yoon, Shenyong Ye, Henok Weldeyesus, Armel Cotten, Tonghang Han, Zhengguang Lu, Zach Hadjri, Junseok Seo, Lihan Shi, Emily Aitken, Prayoga P Liong, Zhenghan Wu, Mingchi Xu, Christian Scheller, Mingyang Zheng, Rasul Gazizulin, Kenji Watanabe, Takashi Taniguchi, Dominique Laroque, Mingda Li, Fan Zhang, Dominik M. Zumbühl, Long Ju
Spin-polarized superconductors offer a rare platform for studying electronic correlations, but few candidate systems have been experimentally confirmed to date. Here, we report the observation of a spin-polarized superconducting state, denoted SC5, in WSe2-proximitized rhombohedral trilayer graphene. At in-plane magnetic field B|| = 0 T, SC5 has a critical temperature of 68 mK and an out-of-plane critical magnetic field of only 12 mT. Surprisingly, these values are significantly enhanced as B|| increases, and the superconductivity persists to B|| = 8.8 T. This value corresponds to a record-high Pauli-limit violation ratio of at least 80 among all superconductors, while the true critical field is beyond the limit of our instrument. We conclude that SC5 experiences a canting crossover from Ising-type to spin-polarized superconductor with increased B||.
Superconductivity (cond-mat.supr-con)
18 pages, 4 figures
Spatial Correlation of Superconducting and Pseudogap Dynamics in a Bi-based Cuprate
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
T. Shimizu, T. Kurosawa, S. Tsuchiya, K. Yamane, R. Morita, M. Oda, Y. Toda
Understanding the interplay between superconductivity and the pseudogap phase is essential for elucidating the mechanism of high-temperature superconductivity in cuprates. Here we provide direct spatial evidence that these two states are locally and intrinsically correlated. Using spatially and temporally resolved measurements of photoinduced quasiparticle dynamics in optimally doped Bi$ _2$ Sr$ _{1.7}$ La$ _{0.3}$ CuO$ _{6+\delta}$ (La-Bi2201), we reveal micrometer-scale spatial contrasts in the transient reflectivity that arise from local variations in the threshold fluence required to disrupt either the superconducting or pseudogap state. The superconducting response remains spatially uniform, whereas the pseudogap exhibits intrinsic inhomogeneity, yet the spatial variations of their threshold fluences closely track each other, establishing a robust local correlation between the two. These results introduce a bulk-sensitive ultrafast optical methodology for visualizing hidden spatial correlations in correlated materials and provide new benchmarks for understanding the intertwined phases in cuprates.
Superconductivity (cond-mat.supr-con)
Two-dimensional flat-bands in Moire-diamonds
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Yalan Wei, Shifang Li, Yuke Song, Chaoyu He
The discovery of flat-bands in magic-angle twisted bilayer graphene has underscored the potential of moire engineering for correlated states, but such phases are notoriously difficult to realize and highly fragile against perturbations. Here, we propose an alternative route to flat-bands by introducing sp3 hybridization in twisted graphite. Instead of relying on fine-tuned magic angles, our approach identifies flat-band states at relatively large twist angles with short moire periods. In this regime, sp3-induced reconstructions generate electronic states that, once formed, are locked by substantial energy barriers, rendering them robust against external perturbations. Using twisted graphite as a prototype, we uncover a series moire-diamond that host two-dimensional flat conduction of valence bands, where carriers are localized within specific momentum planes but remain dispersive along orthogonal directions. The emergence of dimensional flat-bands opens a new platform for flat-band-driven correlated physics and suggests opportunities for designing quantum materials with highly directional electronic functionalities.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
12 pages, 3 figures
Delayed 1T to 2H Phase Transition Upon Electrochemical Delithiation of LiMoS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Yerin Hong, Juhwan Lim, Jinhong Min, Nishkarsh Agarwal, Robert Hovden, Ageeth A. Bol, Yiyang Li
Molybdenum disulfide (MoS2) is a widely studied layered material for electronic, optical, and catalytic applications. It can host lithium ions between the van der Waals layers, which triggers a phase transition between the semiconducting 2H phase and metallic 1T phase. While lithium insertion triggers a phase transition to the 1T phase, the phase behavior upon electrochemical lithium removal is not resolved. In this work, we conduct single-flake electrochemical (de)lithiation of MoS2 using microelectrode arrays. Through both electrochemical voltage analysis and correlative Raman spectroscopy, we show that an electrochemically cycled and delithiated MoS2 flake initially remains in the 1T phase. However, over the course of several days, it transitions back into the thermodynamically stable 2H phase. This result resolves the phase transformation pathway upon delithiation and showcases the ability to electrochemically synthesize the metastable 1T-MoS2 phase.
Materials Science (cond-mat.mtrl-sci), Audio and Speech Processing (eess.AS)
Generalized quantum limits of electrical contact resistance and thermal boundary resistance
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Alice Ho, Jashan Singhal, Deji Akinwande, Huili Grace Xing, Debdeep Jena
The importance of electrical contact resistance and thermal boundary resistance has increased dramatically as devices are scaled to atomic limits. The use of a rich range of materials with various bandstructures (e.g. parabolic, conical), and in geometries exploiting various dimensionalities (e.g. 1D wires, 2D sheets, and 3D bulk) will increase in the future. Here we derive a single general expression for the quantum limit of electrical contact resistivity for various bandstructures and all dimensions. A corresponding result for the quantum limit of thermal boundary resistance is also derived. These results will be useful to quantitatively co-design, benchmark, and guide the lowering of electrical and thermal boundary resistances for energy efficient devices.
Materials Science (cond-mat.mtrl-sci)
4 Pages, 2 Figures, 1 Table
Impact of elastic inhomogeneity on collective dynamical properties investigated by field theoretical description in real space
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
Interpreting the vibrational properties of amorphous solids beyond Debye’s theory is challenging due to the presence of inhomogeneity on the mesoscopic scale. In this work, we model this inhomogeneity by real-space fluctuating elasticity with a spatially correlated distribution and calculate the dynamical properties using an exact real-space field theoretical approach. Our results clarify that the excess low-frequency density of states (DOS) originates from a selective scattering effect (stronger scattering of short wavelengths) induced by elastic inhomogeneity. The visualization of the local DOS in real space reveals the existence of anomalous modes, highly excited spots, at low frequencies. The findings regarding these highly excited spots and the selectivity of the correlation length were missed in previous perturbative field approaches in wave-vector space, and they align with recent progress from particle-level simulations and experiments. These results provide concrete insights into the low-frequency vibrational anomaly of amorphous solids from the perspective of simple elastic inhomogeneity.
Soft Condensed Matter (cond-mat.soft)
8 pages, 5 figures
Phase-sensitive evidence for 2x2 pair density wave in a kagome superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
Xiao-Yu Yan, Guowei Liu, Hanbin Deng, Xitong Xu, Haiyang Ma, Hailang Qin, Jun-Yi Zhang, Yuanyuan Zhao, Haitian Zhao, Zhe Qu, Yigui Zhong, Kozo Okazaki, Xiquan Zheng, Yingying Peng, Zurab Guguchia, X. X. Wu, Qianghua Wang, X-H Fan, Wei Song, M-W Gao, Hendrik Hohmann, Matteo Durrnagel, Ronny Thomale, Jia-Xin Yin
The pair-density-wave (PDW) exhibits periodic amplitude and sign modulations of the superconducting order parameter. Such a pairing state has been proposed to be sensitive to nonmagnetic scattering. In this work, we observe the nonmagnetic PDW-breaking effect in a kagome superconductor, using scanning tunneling microscopy. We observe 2x2 PDW induced by the coupling between charge order and superconductivity. The global PDW is substantially suppressed upon doping the kagome lattice with dilute isovalent nonmagnetic impurities, whereas the charge order and uniform superconductivity remain robust. Spatial correlation analysis further confirms that PDW is distinctly suppressed near dopants. We attribute the PDW suppression to a nonmagnetic PDW breaking effect, arising from phase sign modulation of PDW in the kagome d-orbital hosting Bogoliubov Fermi states.
Superconductivity (cond-mat.supr-con)
Collinear, incommensurate antiferromagnetism in van der Waals magnet alpha-UTe3
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
H. Sakai, C. Tabata, K. Kaneko, Y. Tokiwa, T. Kitazawa, S. Kambe, Y. Tokunaga, Y. Haga
alpha-UTe3, a van der Waals (vdW) actinide compound with a monoclinic ZrSe3-type structure, is a narrow-gap semiconductor with 5f moments. 125Te NMR reveals strongly anisotropic, layer-confined spin fluctuations below about 20 K, with the a-axis component enhanced, and a signal wipeout at the antiferromagnetic (AFM) transition at TN = 5 K. Single-crystal neutron diffraction finds q approx. (0.17, 0.5, 0) and a longitudinal sinusoidal modulation of a-axis moments (amplitude about 0.8 muB) with AFM stacking along b. A CEF singlet-singlet induced-moment framework accounts for the easy-axis anisotropy, the small heat-capacity anomaly at TN, the reduced ordered moment, and the exchange-driven selection of q in this localized 5f vdW magnet, establishing a constrained exchange geometry stabilizing this in-plane incommensurate state.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 7 figures
Frenkel anomaly on co-ordination numbers in liquid CO2 at 100 and 1000 bar studied by Monte Carlo simulation using Kihara potential model
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
An issue concerning the Frenkel line of liquid CO2 is that its location has not been unequivocally determined. So far, reliable Frenkel lines were identified from velocity autocorrelation functions (VAFs) computed by Molecular Dynamic simulations; however VAFs cannot be directly verified experimentally. By contrast, the co-ordination numbers (CNs) can be measured experimentally by X-ray and neutron scattering or computed by Monte Carlo (MC) simulation, and thus provide an alternative means of determining the location of the Frenkel line. In the present study, the CNs were computed by MC simulation using the Kihara potential, and the Frenkel anomalies were identified at {P = 100 bar, T = 260 K}, in good agreement with previous results based on VAFs, and at {P = 1000 bar, T = 370 K}, which deviates significantly from them.
Materials Science (cond-mat.mtrl-sci)
20 pages, 15 figures
Entropy Engineering-Regulated Electron-Phonon Coupling for Highly Efficient Photoluminescence in Se-doped WS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Chi Zhang, Quan Shen, Mengmeng Zhang, Zhiming Deng, Taishen Wu, Xuying Zhong, Gang Ouyang, Dongsheng Tang, Qi Zheng, Jiansheng Dong, Weichang Zhou
The limited quantum yield of strained monolayer transition metal dichalcogenides grown by vapor-phase methods and during transfer-based stacking poses a fundamental challenge for their optoelectronic applications. Here, we introduce the concept of “entropy engineering” as a transformative strategy to selectively enhance light-matter interactions through controlled electron-phonon coupling. We unveil how tailored entropy introduced via precise selenium doping or interfacial van der Waals proximity can significantly amplify radiative recombination from momentum-dark excitons in WS2 monolayers. Notably, we discover that slight selenium doping drastically enhances the photoluminescence (PL) of WS2 under strain. While both undoped and heavily doped WS2 suffer from strong PL quenching owing to the direct-to-indirect bandgap transition, lightly Se-doped samples exhibit an order-of-magnitude increase in emission intensity. This counterintuitive boost is traced to doping-induced structural disorder, which intensifies electron-phonon interactions and unlocks efficient phonon-assisted emission from otherwise non-radiative indirect excitons. Moreover, we demonstrate that van der Waals coupling to adjacent Se-doped layers can impart interfacial entropy and further augment PL via proximity effects. Our work highlights entropy engineering via controlled doping as a powerful strategy for activating high-efficiency light emission in atomically thin semiconductors.
Materials Science (cond-mat.mtrl-sci)
Local-Antisymmetric Flat Band and Coexisting Correlated stripe charge orders in WSe2-Modulated Twisted Bilayer Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Chi Zhang, Shihao Zhang, Mengmeng Zhang, Lin He, Qi Zheng
Insulating, atomically flat transition metal dichalcogenides (TMDs) like WSe2 are ideal substrates for probing intrinsic graphene properties. Conventionally, their influence on graphene’s band structure is assumed negligible, particularly when small moire patterns form. Combining scanning tunneling microscopy/spectroscopy and theoretical analysis, we reveal that the atomic registry in graphene/WSe2 heterostructures profoundly modulates the electronic structure of magic-angle twisted bilayer graphene (MATBG). At special graphene/WSe2 twist angles, an incommensurate moire superlattice hosts three distinct atomic stacking configurations (A, B, X types). These induce position-dependent potentials that asymmetrically shift MATBG’s flat bands, transforming them from hole-side to electron-side asymmetric within a single AA-stacked region. This symmetry breaking enables the unprecedented coexistence of orthogonal stripe charge orders in the correlated regime-a phenomenon previously considered mutually exclusive due to Coulomb repulsion. This band modulation arises from the synergistic effects of the graphene/WSe2 interfacial atomic registry and heterostrain within the MATBG, exhibiting multi-field tunability. Our work establishes interfacial atomic registry as a critical, previously overlooked tuning parameter for flat-band physics, opening avenues to engineer correlated quantum states in van der Waals heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
In-plane polar domains enhanced energy storage
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Yu Lei, Xiaoming Shi, Sihan Yan, Qinghua Zhang, Jiecheng Liu, Sixu Wang, Yu Chen, Jiaou Wang, He Qi, Qian Li, Ting Lin, Jingfen Li, Qing Zhu, Haoyu Wang, Jing Chen, Lincong Shu, Linkun Wang, Han Wu, Xianran Xing
Relaxor ferroelectric thin films are recognized for their ultrahigh power density, rendering them highly promising for energy storage applications in electrical and electronic systems. However, achieving high energy storage performance with chemically homogeneous, environmentally friendly and compositionally stable materials remains challenging. In this work, we present a design of dielectrics with high energy storage performance via an in-plane polar domains incorporating polar nanoregions mechanism. Guided by phase-field simulations, we synthesized La/Si co-doping BaTiO3 solid-solution thin films with high chemical homogeneity to realize high energy storage performance. Given that, we achieve a high energy density of 203.7J/cm3 and an energy efficiency of approximately 80% at an electric field of 6.15MV/cm. This mechanism holds significant promise for the design of next-generation high-performance dielectric materials for energy storage and other advanced functional materials.
Materials Science (cond-mat.mtrl-sci)
Thin-film flows of granular suspensions on a solid surface
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
Alice Pelosse, Elisabeth Guazzelli, Matthieu Roché
This review article examines the complex dynamics of thin-film flows of granular suspensions spreading over rigid solid substrates with free air interfaces. Such systems feature an involved coupling of the free-surface dynamics with the flow and microstructure of the suspension. In particular, we develop two canonical thin-film situations: drop spreading and dip-coating. In drop spreading, confinement of the particulate phase near the advancing contact line alters both the spreading rate and the interface shape. In dip-coating, understanding the entrainment of fluid and particles becomes challenging as the film thickness approaches the particle size.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
16 pages, 13 figures
Spinon band flattening by its emergent gauge field in quantum kagome ice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Masafumi Udagawa, Roderich Moessner
Fractional excitations provide a key to identifying sought-after topological quantum spin liquid states in realistic materials. Their single-particle dynamics already presents a challenging many-body problem on account of the coupling to their emergent gauge field. Here, we study the spinon excitations of kagome ice, realized at the $ 2/3$ magnetization plateau of spin ice, by combining up-to-$ 63$ -site exact diagonalization with an analytical state graph mapping. We find a macroscopically degenerate mode in the spinon spectrum. It originates from the destructive interference due to the interaction with surrounding gauge fields, a form of many-body caging. We explicitly construct, and count, the concomitant many-body wave functions. Finally, we discuss the possible role of these flat modes in the magnetization process of kagome antiferromagnets, in particular with regard to the asymmetric termination of the kagome ice magnetisation plateau.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
6 pages, 3 figures
Should it really be that hard to model the chirality induced spin selectivity effect?
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
The chirality induced spin selectivity effect remains a challenge to capture with theoretical modeling. While at least a decade was spent on independent electron models, which completely fail to reproduce the experimental results, the lesson to be drawn out of these efforts is that a correct modeling of the effect has to include interactions among the electrons. In the discussion of the phenomenon ones inevitably encounters the Onsager reciprocity and time-reversal symmetry, and questions whether the observations violate these fundamental concepts, or whether we have not been able to identify what it is that make those concepts redundant in this context. The experimental fact is that electrons spin-polarize by one or another reason, when traversing chiral molecules. The set-ups are simple enough to enable effective modeling, however, overcoming the grand failures of the theoretical efforts, thus far, and formulating a theory which is founded on microscopic modeling appears to be a challenge. A discussion of the importance of electron correlations is outlined, pointing to possible spontaneous breaking of time-reversal symmetry and Onsager reciprocity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 4 figures, accepted in APL Computational Physics (2025)
Optimizing Cross-Domain Transfer for Universal Machine Learning Interatomic Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Jaesun Kim, Jinmu You, Yutack Park, Yunsung Lim, Yujin Kang, Jisu Kim, Haekwan Jeon, Deokgi Hong, Seung Yul Lee, Saerom Choi, Yongdeok Kim, Jae W. Lee, Seungwu Han
Accurate yet transferable machine-learning interatomic potentials (MLIPs) are essential for accelerating materials and chemical discovery. However, most universal MLIPs overfit to narrow datasets or computational protocols, limiting their reliability across chemical and functional domains. We introduce a transferable multi-domain training strategy that jointly optimizes universal and task-specific parameters through selective regularization, coupled with a domain-bridging set (DBS) that aligns potential-energy surfaces across datasets. Systematic ablation experiments show that small DBS fractions (0.1%) and targeted regularization synergistically enhance out-of-distribution generalization while preserving in-domain fidelity. Trained on fifteen open databases spanning molecules, crystals, and surfaces, our model, SevenNet-Omni, achieves state-of-the-art cross-domain accuracy, including adsorption-energy errors below 0.06 eV on metallic surfaces and 0.1 eV on metal-organic frameworks. Despite containing only 0.5% r$ ^2$ SCAN data, SevenNet-Omni reproduces high-fidelity r$ ^2$ SCAN energetics, demonstrating effective cross-functional transfer from large PBE datasets. This framework offers a scalable route toward universal, transferable MLIPs that bridge quantum-mechanical fidelities and chemical domains.
Materials Science (cond-mat.mtrl-sci)
24 pages, 4 figures, 2 tables
Spreading fronts: numerical simulations on discrete models and continuous equations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-14 20:00 EDT
Out-of-equilibrium systems, inherently complex and challenging to understand, are prevalent across various disciplines, including physics where they arise in contexts such as fluid dynamics. In particular, critical out-of-equilibrium systems combine this complexity with the scaling laws and universality classes observed in critical phenomena, with kinetic surface roughening, the study of how a flat surface becomes progressively rougher over time, serving as a prime example. This behavior manifests in a wide variety of contexts, including metal corrosion, cell proliferation, and, notably, the growth of thin films, which can emerge as a result of wetting processes. In this thesis, we conduct extensive numerical simulations to study critical fluctuations and identify universal features of several rough interfaces, generated by simulating discrete models of thin film growth and by performing direct numerical integration of continuum equations. To explore the universal behavior of these interfaces, we identify the critical exponents that characterize the spatio-temporal fluctuations of the front. Additionally, we analyze the dynamics of thin films across different physical scenarios to deepen our understanding of their behavior in out-of-equilibrium conditions, especially in the case where these films are formed by the action of an external force such as Surface Acoustic Waves.
Statistical Mechanics (cond-mat.stat-mech)
Ph.D Thesis defended at the University of Extremadura on the 7th of July of 2025
Superconducting spin valve effect in Fe/Si$_3$N$_4$/Pb/Si$_3$N$_4$/Fe heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
A. A. Kamashev, N. N. Garif’yanov, A. A. Validov, A. S. Osin, Ya. V. Fominov, I. A. Garifullin
The structures of the superconducting spin valve (SSV) Fe/\allowbreak Si$ _3$ N$ _4$ /\allowbreak Pb/\allowbreak Si$ _3$ N$ _4$ /\allowbreak Fe (where Si$ _3$ N$ _4$ is a dielectric insulating layer of controlled thickness) were investigated. The dependence of the magnitude of the SSV effect on the thicknesses of the superconducting (S) and insulating (I) layers was studied. Optimization of the S and I layer thicknesses enabled a complete switching between the normal and superconducting states when the mutual orientation of the magnetizations of the ferromagnetic (F) layers changed from antiparallel to parallel. A maximal SSV effect value of 0.36,K was achieved in an external magnetic field of 1,kOe. These results demonstrate that SSV structures with tunable S/F interface transparency controlled by insulating interlayers are promising for achieving a significant magnitude of the effect. This opens new avenues for the development of such systems and their potential applications in spintronic devices.
Superconductivity (cond-mat.supr-con)
8 pages, 7 figures
Behavior of passive polymeric tracers of different topologies in a dilute bath of active Brownian particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
Ramanand Singh Yadav, Ralf Metzler, Rajarshi Chakrabarti
Using computer simulations in two dimensions we investigate the dynamics and structure of passive polymeric tracer with different topologies immersed in a low-density active particle bath. One of the key observations is that polymer exhibit faster dynamics compared to passive colloidal particles at high activity, for the same particle density, in both linear and star polymer topologies. This enhanced motion is attributed to the accumulation of active particles, which induces prolonged and persistent movement of the polymer. Further analysis reveals that star polymers exhibit more complex and intriguing behavior than their linear counterparts. Notably, the accumulation of active particles promotes the pairing of arms in star polymers. For instance, a three-armed star polymer adopts a conformation similar to a linear polymer with two-arms due to this pairing as a result, at high activity, the dynamics of both the polymers converge. Finally, we explore the dynamics of a linear polymer with the same total number of beads as the star polymer. Interestingly, at high activity – where arm pairing in the star polymer is significant – the star polymer demonstrates faster dynamics than the linear polymer, despite having the identical number of beads. These findings contribute to a broader understanding of the interactions between active and passive components of varying topologies in dilute systems and highlight their potential for innovative applications ranging from materials science to biomedicine.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
17 pages, 15 figures, RevTeX; access to supplementary movies on reasonable request
One-dimensional topological superconductors with nonsymmorphic symmetries
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
We present example four-band Hermitian tight-binding Bogoliubov-de-Gennes (BdG) Hamiltonians and Kramer’s degenerate Hamiltonians in one dimension. Starting from a generalized Rice-Mele model, we incorporate superconducting terms to obtain a four-band BdG Hamiltonian with intrinsic charge-conjugation symmetry, and constrain it using symmorphic or nonsymmorphic time-reversal symmetries. In position space we find that each form of time-reversal symmetry, when applied to random BdG matrices, results in a unique block diagonalization of the Hamiltonian when translational symmetry is also enforced. We provide representative models in all relevant symmorphic symmetry classes, including the non-superconducting CII class. For nonsymmorphic time-reversal symmetry, we identify a $ \mathbb{Z}_4$ topological index with two phases supporting Majorana zero modes and two without, and study disorder effects in the presence of topological solitons. We further generalize a winding-number method, previously applied only to $ \mathbb{Z}_2$ invariants without Kramer’s degeneracy, to compute indices for both the $ \mathbb{Z}_4$ model and a non-superconducting AII model with nonsymmorphic chiral symmetry and Kramer’s degeneracy. We propose topolectric circuit implementations of the charge-density-wave and $ \mathbb{Z}_4$ models which agree with the topological calculations. Finally, we show that, in one dimension, nonsymmorphic unitary symmetries do not produce new topological classifications beyond $ \mathbb{Z}$ or $ \mathbb{Z}_2$ indices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
28 pages, 22 figures, plus supplementary 9 pages, 2 figures
Electron-phonon coupling in magnetic materials using the local spin density approximation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Á. A. Carrasco Álvarez, M. Giantomassi, J. Lihm, G. E. Allemand, M. Mignolet, M. Verstraete, S. Poncé
Magnetic materials are crucial for manipulating electron spin and magnetic fields, enabling applications in data storage, spintronics, charge transport, and energy conversion, while also providing insight into fundamental quantum phenomena. In numerous applications, the interaction between electrons and lattice vibrations, known as electron-phonon coupling, can be of significant importance. In that regard, we extend the EPW package to be able to interpolate the electron-phonon matrix elements combining perturbation theory and maximally localized Wannier functions. This allows to use dense momentum grids at a reasonable computational cost when computing electron-phonon-related quantities and physical properties. We validate our implementation considering ferromagnetic iron and nickel, where we explore the absence of phonon-driven superconductivity, finding that superconductivity is intrinsically suppressed. Furthermore, we evaluate the carrier resistivity at finite temperatures for both systems, considering the role of the magnetic phase in carrier transport. Our findings indicate that in the case of Fe, the primary contributor to resistivity is electron-phonon scattering. In contrast, for Ni, electron-phonon scattering constitutes less than one-third of the resistivity, underscoring a fundamental difference in the transport properties of the two systems.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Main manuscript 13 pages, 8 Figures Supplemental 8 pages, 11 Figures
Nonequilibrium spin-splitter effect in altermagnet superconductor hybrids
New Submission | Superconductivity (cond-mat.supr-con) | 2025-10-14 20:00 EDT
Tim Kokkeler, Tero T. Heikkilä, F. Sebastian Bergeret
We study the nonequilibrium spin-splitter effect in superconducting altermagnets and superconductor altermagnet hybrids by computing the alternating spin current and edge the spin density in the presence of an alternating electric field. We show that while in the normal state the effect is not sensitive to the field frequency, in the superconducting state, there is a strong effect for frequencies on the scale of $ \Delta_0$ or lower. We contrast the effect to the spin accumulation induced by the spin-Hall effect, by showing that for the altermagnet spin-splitter effect the out-of-phase spin density does not diverge in the adiabatic limit. This difference is attributed to the absence of any equilibrium spin-splitter effect in altermagnets. In fact, the out-of-phase component vanishes below the gap excitation frequency $ 2\Delta_0$ , because below this frequency the absence of dissipation and the behavior of the system under time-reversal directly determine the relative phase between the charge current, spin current, and spin accumulation. The nonequilibrium effect can be tuned by external parameters like temperature. In fact, it has a nonmonotonic temperature dependence, taking its largest value for temperatures around $ 0.8T_{c}$ . The value at this temperature can be significantly larger than the normal state spin density or the low temperature spin density. Thus, besides using the nonequilibrium spin-splitter effect to identify altermagnets, its tunability makes it also suitable for applications.
Superconductivity (cond-mat.supr-con)
9 pages, 6 figures
Deterministic Switching in Altermagnets via Asymmetric Sublattice Spin Current
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Sayan Sarkar, Sunit Das, Amit Agarwal
We demonstrate a deterministic switching mechanism in collinear altermagnets driven by asymmetric sublattice spin currents. Unlike conventional antiferromagnets, where combined parity-time-reversal symmetry enforces purely staggered sublattice spin torques, altermagnets host symmetry-protected nonrelativistic spin splitting that produces unequal torques on the two sublattices. Using doped FeSb$ _2$ as a representative $ d$ -wave altermagnet, our Landau–Lifshitz–Gilbert simulations show that these torques enable magnetic-field-free and deterministic 180$ ^\circ$ Néel vector reversal over picosecond timescale. The mechanism is generic to even-parity altermagnets and remains effective even in centrosymmetric, weak spin-orbit coupled systems, where the Néel spin-orbit torque mechanism fails. Our results establish an experimentally accessible mechanism for switching of altermagnetic order, opening pathways for realizing ultrafast, low-power altermagnet spintronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
4+1 figures, 1 table, comments are most welcome
Host-atom-driven transformation of a honeycomb oxide into a dodecagonal quasicrystal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Martin Haller, Julia Hewelt, V. Y. M. Rajesh Chirala, Loi Vinh Tran, Ankur Bhide, Muriel Wegner, Stefan Förster, Wolf Widdra
Dodecagonal oxide quasicrystals (OQCs) have so far been limited to a few elemental systems, with no general formation mechanism established. Here, we demonstrate a versatile approach to OQC formation via a host-atom-induced transformation of a metal-oxide honeycomb (HC) network. Adsorption of Ba, Sr, or Eu onto the HC layer triggers its reorganization into a dodecagonal tiling, as revealed by low-energy electron diffraction and scanning tunneling microscopy. Full conversion occurs when 73% of the honeycomb rings are occupied. Kelvin probe and UV photoelectron spectroscopy show a linear decrease in work function with increasing host coverage, followed by a sharp increase upon quasicrystal formation due to reduced host dipoles. This transformation mechanism enables the fabrication of structurally precise OQCs, including a new Eu-Ti-O phase that extends the field to lanthanide quasicrystals, forming a 2D grid of localized magnetic moments. The method offers a general route to explore lattice-matched substrates for epitaxial growth and may be adapted to other 2D honeycomb materials - such as graphene, hexagonal ice, and silica - paving the way for engineered aperiodic systems beyond transition metal oxides.
Materials Science (cond-mat.mtrl-sci)
A minimal and universal representation of fermionic wavefunctions (fermions = bosons + one)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Representing fermionic wavefunctions efficiently is a central problem in quantum physics, chemistry and materials science. In this work, we introduce a universal and exact representation of continuous antisymmetric functions by lifting them to continuous symmetric functions defined on an enlarged space. Building on this lifting, we obtain a \emph{parity-graded representation} of fermionic wavefunctions, expressed in terms of symmetric feature variables that encode particle configuration and antisymmetric feature variables that encode exchange statistics. This representation is both exact and minimal: the number of required features scales as $ D\sim N^d$ ($ d$ is spatial dimension) or $ D\sim N$ depending on the symmetric feature maps employed. Our results provide a rigorous mathematical foundation for efficient representations of fermionic wavefunctions and enable scalable and systematically improvable neural network solvers for many-electron systems.
Strongly Correlated Electrons (cond-mat.str-el), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
6 pages
Intermediate chiral edge states in quantum Hall Josephson junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Partha Sarathi Banerjee, Rahul Marathe, Sankalpa Ghosh
A transfer-matrix-based theoretical framework is developed to study transport in superconductor-quantum Hall-Superconductor (SQHS) Josephson junctions modulated by local potential barriers in the quantum-Hall regime. The method allows one to evaluate the change in the conductivity of such SQHS Josephson junctions contributed by the intermediate chiral edge states (ICES) induced by these local potential barriers at their electrostatic boundaries at specific electron filling-fractions. It is particularly demonstrated how these ICES created at different Landau levels (LL) overlap with each other through intra- and inter-LL ICES mixing with the change in strength and width of the potential barriers. This results in different mechanisms for forming Landau bands when an array of such potential barriers are present. It is also demonstrated that our theoretical framework can be extended to study the lattice effect in a bounded domain in such SQHS Josephson junctions by simultaneously submitting the normal region to a transverse magnetic field and periodic potential.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
17 latexed pages and five figures
Nonanaliticities and ergodicity breaking in noninteracting many-body dynamics via stochastic resetting and global measurements
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-14 20:00 EDT
David Soldner, Igor Lesanovsky, Gabriele Perfetto
Stochastic resetting generates nonequilibrium steady states by interspersing unitary quantum dynamics with resets at random times. When the state to which the system is reset is chosen conditionally on the outcome of a global and spatially resolved measurement, the steady state can feature collective behavior similar to what is typically observed at phase transitions. Here we investigate such conditional reset protocol in a system of noninteracting spins, where the reset state is chosen as a magnetization eigenstate, that is selected (conditioned) on the outcome of a previous magnetization measurement. The stationary states that emerge from this protocol are characterized by the density of spins in a given magnetization eigenstate, which is the analogue of the order parameter. The resulting stationary phase diagram features multiple nonanalytic points. They are of first-order type for half-integer spin, while multicritical behavior, signalled by both first and second-order discontinuities, is found for integer spin. We also show that the associated dynamics is nonergodic, i.e., which stationary state the system ultimately assumes is determined be the initial state. Interestingly, the mechanism underlying these phenomena does not rely on interactions, but the emergent nonlinear behavior is solely a consequence of correlations induced by the measurement.
Statistical Mechanics (cond-mat.stat-mech)
Main text 17 pages and 9 figures, appendices 12 pages and 5 figures
Efficient and accurate tensor network algorithm for Anderson impurity problems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Zhijie Sun, Zhenyu Li, Chu Guo
The Anderson impurity model (AIM) is of fundamental importance in condensed matter physics to study strongly correlated effects. However, accurately solving its long-time dynamics still remains a great numerical challenge. An emergent and rapidly developing numerical strategy to solve the AIM is to represent the Feynman-Vernon influence functional (IF), which encodes all the bath effects on the impurity dynamics, as a matrix product state (MPS) in the temporal domain. The computational cost of this strategy is basically determined by the bond dimension $ \chi$ of the temporal MPS. In this work, we propose an efficient and accurate method which, when the hybridization function in the IF can be approximated as the summation of $ n$ exponential functions, can systematically build the IF as a MPS by multiplying $ O(n)$ small MPSs, each with bond dimension $ 2$ . Our method gives a worst case scaling of $ \chi$ as $ 2^{8n}$ and $ 2^{2n}$ for real- and imaginary-time evolution respectively. We demonstrate the performance of our method for two commonly used bath spectral functions, where we show that the actually required $ \chi$ s are much smaller than the worst case.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
11 pages, 4 figures
Enhancing the Plasmonic Hotspot Density via Structural Engineering of Multi-layered MoO3-Ag-Au Systems Under Extreme Electronic Excitation Conditions for Ultra-Sensitive SERS Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Om Prakash, Sharmistha Dey, Mayur Khan, Abhijith T, Udai Bhan Singh, Ambuj Tripathi, Santanu Ghosh
We illustrate ion-beam engineering of MoO3 Ag Au multilayer plasmonic substrates to improve SERS performance, We illustrate ion-beam engineering of MoO3-Ag-Au multilayer plasmonic substrates to improve SERS performance. Orthorhombic {\alpha}-MoO3 microflakes were produced via chemical vapour deposition (CVD) on Si-SiO2 substrates. Thin films of Ag (5 nm) and Au (5 nm) were thermally evaporated onto the MoO3 flakes, and the samples were subjected to 100 MeV Ag8+ swift heavy ion irradiation at fluences of 3e11 and 3e12 ions cm-2. Irradiation causes dewetting of metal films, prompting structural and morphological changes that result in the formation of dispersed Ag-Au nanoparticles, enhanced surface roughness, and defect generation within the MoO3 lattice. X-ray diffraction (XRD) verifies the {\alpha}-MoO3 phase; field emission scanning electron microscopy (FESEM) elucidates nanoparticle formation and surface reorganisation; Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) disclose vibrational alterations and binding-energy shifts in Mo 3d, indicative of oxygen vacancies (V_O) and partial reduction of Mo. SERS measurements of molecular probes demonstrate significantly increased Raman intensities following ion irradiation.
Materials Science (cond-mat.mtrl-sci)
Effects of strain on the stability of the metallic rutile and insulating M1 phases of vanadium dioxide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Peter Mlkvik, Lena Geistlich, Nicola A. Spaldin, Claude Ederer
We present a systematic density-functional theory study of the effects of strain on the structural and electronic properties in vanadium dioxide (VO$ _2$ ), with particular emphasis on its effect on the relative stability of the metallic rutile and the insulating monoclinic M1 phases. We consider various strain conditions that can be related to epitaxial strain present in VO$ _2$ films grown on different lattice planes. Our calculations confirm the dominant role of $ c$ axis strain, i.e., along the direction of the V-V dimerization in the M1 phase. Our analysis suggests that this effect stems primarily from the weakening of the lattice stiffness, with the hopping along the $ c$ axis playing a minor role. We also confirm that, in strain scenarios that deform the basal plane, the $ c$ axis strain still has a dominant effect on the phase stability.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Spinons, solitons and random singlets in the spin-chain compound copper benzoate
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Ying Chen, Guijing Duan, Yuejiu Zhao, Ning Xi, Bingying Pan, Xiaoyu Xu, Zhanlong Wu, Kefan Du, Shuo Li, Ze Hu, Rui Bian, Xiaoqun Wang, Wei Li, Long Zhang, Yi Cui, Shiyan Li, Rong Yu, Weiqiang Yu
The $ S=1/2$ antiferromagnetic Heisenberg chain is a paradigmatic quantum system hosting exotic excitations such as spinons and solitons, and forming random singlet state in the presence of quenched disorder. Realizing and distinguishing these excitations in a single material remains a significant challenge. Using nuclear magnetic resonance (NMR) on a high-quality single crystal of copper benzoate, we identify and characterize all three excitation types by tuning the magnetic field at ultra-low temperatures. At a low field of 0.2 T, a temperature-independent spin-lattice relaxation rate ($ 1/T_1$ ) over more than a decade confirms the presence of spinons. Below 0.4 K, an additional relaxation channel emerges, characterized by $ 1/T_1 \propto T$ and a spectral weight growing as $ -\ln(T/T_0)$ , signaling a random-singlet ground state induced by weak quenched disorder. At fields above 0.5 T, a field-induced spin gap $ \Delta \propto H^{2/3}$ observed in both $ 1/T_1$ and the Knight shift signifies soliton excitations. Our results establish copper benzoate as a unique experimental platform for studying one-dimensional quantum integrability and the interplay of disorder and correlations.
Strongly Correlated Electrons (cond-mat.str-el)
Disorder to Order Transition in 1D Nonreciprocal Cahn-Hilliard Model
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-10-14 20:00 EDT
Navdeep Rana, Ramin Golestanian
We extensively study the phenomenology of one dimensional Nonreciprocal Cahn Hilliard model for varying nonreciprocity $ (\alpha)$ and different boundary conditions. At small $ \alpha$ , a perturbed uniform state evolves to a defect laden configuration that lacks global polar order. Defects are the sources and sinks of travelling waves and nonreciprocity selects defects with a unique wave number that increases monotonically with $ \alpha_c$ . A critical threshold $ \alpha_c$ marks the onset of a transition to states with finite global polar order. For periodic boundaries, above $ \alpha_c$ , the system shows travelling waves that are completely ordered. In contrast, travelling waves are incompatible with Dirichlet and Neumann boundaries. Instead, for $ \alpha \gtrsim \alpha_c$ , we find fluctuating domains that show intermittent polar order and at large $ \alpha$ , the system partitions into two domains with opposite polar order.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
9 pages and 9 figures
Ab-initio calculation of magnetic exchange interactions using the spin-spiral method in VASP: Self-consistent versus magnetic force theorem approaches
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Umit Dogan Daglum, Maria Stamenova, Ersoy Sasioglu, Stefano Sanvito
We present an ab initio investigation of magnetic exchange interactions using the spin-spiral method implemented in the VASP code, with a comparative analysis of the self-consistent (SC) and magnetic force theorem (MFT) approaches. Using representative 3d ferromagnets (Fe, Co, Ni) and Mn-based full Heusler compounds, we compute magnon dispersion relations directly from spin-spiral total energies and extract real-space Heisenberg exchange parameters via Fourier transformation. Curie temperatures are subsequently estimated within both the mean-field and random-phase approximations. The SC spin-spiral calculations yield exchange parameters and magnon spectra in excellent agreement with previous theoretical data, confirming their quantitative reliability across different classes of magnetic systems. In contrast, the MFT approach exhibits systematic quantitative deviations: it overestimates spin-spiral energies and exchange couplings in high-moment systems such as bcc Fe and the Mn-based Heuslers, while underestimating them in low-moment fcc Ni. The magnitude of these discrepancies increases strongly with magnetic moment size, exceeding several hundred percent in the high-moment compounds. These findings underscore the decisive role of self-consistency in accurately determining magnetic exchange parameters and provide practical guidance for future first-principles studies of spin interactions and excitations using the spin-spiral technique.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
11 pages, 4 figures
Flux confinement-deconfinement transition of dimer-loop models on three-dimensional bipartite lattices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-10-14 20:00 EDT
Motivated by recent work that mapped the low-temperature properties of a class of frustrated spin $ S=1$ kagome antiferromagnets with competing exchange and single-ion anisotropies to the fully-packed limit (with each vertex touched by exactly one dimer or nontrivial loop) of a system of dimers and nontrivial (length $ s > 2$ ) loops on the honeycomb lattice, we study this fully-packed dimer-loop model on the three-dimensional bipartite cubic and diamond lattices as a function of $ w$ , the relative fugacity of dimers. We find that the $ w \rightarrow 0$ O($ 1$ ) loop-model limit is separated from the $ w \rightarrow \infty$ dimer limit by a geometric phase transition at a nonzero finite critical fugacity $ w_c$ : The $ w>w_c$ phase has short loops with an exponentially decaying loop-size distribution, while the $ w<w_c$ phase is dominated by large loops whose loop-size distribution is governed by universal properties of the critical O($ 1$ ) loop soup. This transition separates two {\em distinct} Coulomb liquid phases of the system: Both phases admit a description in terms of a fluctuating divergence-free polarization field $ P_{\mu}(\mathbf{r})$ on links of the lattice and are characterized by dipolar correlations at long distances. The transition at $ w_c$ is a flux confinement-deconfinement transition. Equivalently, and independent of boundary conditions, half-integer test charges $ q=\pm 1/2$ are confined for $ w>w_c$ , but become deconfined in the small-$ w$ phase. Although both phases are unstable to a nonzero fugacity for the charge $ \pm 1/2$ excitations, the destruction of the $ w >w_c$ Coulomb liquid is characterized by an interesting slow crossover, since test charges with $ q=\pm 1/2$ are confined in this phase.
Statistical Mechanics (cond-mat.stat-mech)
Deterministic hBN bubbles as a versatile platform for studies on single-photon emitters
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Piotr Tatarczak, Tomasz Fąs, Jan Pawłowski, Aleksandra Krystyna Dąbrowska, Jan Suffczyński, Piotr Wróbel, Andrzej Wysmołek, Johannes Binder
Single-photon emitters (SPEs) in two-dimensional materials are highly promising candidates for quantum technologies. SPEs in hexagonal boron nitride (hBN) have been widely investigated, but mostly in exfoliated or powder samples that require an activation process, making it difficult to compare studies and reproduce results. Here, we address this problem and propose a platform based on large-area metaloraganic vapour phase epitaxy (MOVPE)-grown hBN, which combines reproducibility and scalability with the ability to readily host SPEs without activation. Through the creation of bubbles via electron-beam irradiation, we achieve additional functionalities, including an interference-mediated enhancement of emission by approximately 100-200%, dedicated structures that allow the relocation of individual emitters across different systems, and the opportunity to investigate strain-induced effects. Moreover, in contrast to other gas-filled bubbles that deflate at low temperatures, our bubbles remain stable under cryogenic conditions, allowing studies as a function of temperature. To improve the control over the shape and position of bubbles, we demonstrate a~mask-based method that enables deterministic control over bubble formation. The presented hBN bubbles constitute a versatile platform for reproducible studies of hBN-based emitters, providing a reliable insight into their nature and properties.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Strain-induced multiferroicity in Cr1/3NbS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-10-14 20:00 EDT
Y. Sun, Y. Ahn, D. Sapkota, H. S. Arachchige, R. Xue, S. Mozaffari, D. G. Mandrus, L. Zhao, J. Orenstein, V. Sunko
Multiferroic materials, in which electric polarization and magnetic order coexist and couple, offer rich opportunities for both fundamental discovery and technology. However, multiferroicity remains rare due to conflicting electronic requirements for ferroelectricity and magnetism. One route to circumvent this challenge is to exploit the noncollinear ordering of spin cycloids, whose symmetry permits the emergence of polar order. In this work, we introduce another pathway to multiferroic order in which strain generates polarization in materials that host nonpolar spin spirals. To demonstrate this phenomenon, we chose the spin spiral in the well-studied helimagnet Cr1/3NbS2. To detect the induced polarization, we introduce the technique of magnetoelectric birefringence (MEB), an optical probe that enables spatially-resolved and unambiguous detection of polar order. By combining MEB imaging with strain engineering, we confirm the onset of a polar vector at the magnetic transition, establishing strained Cr1/3NbS2 as a type-II multiferroic.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Strongly Correlated Electrons (cond-mat.str-el)
Finite-temperature phase diagram and collective modes of coherently coupled Bose mixtures
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-10-14 20:00 EDT
Sunilkumar V, Rajat, Sandeep Gautam, Arko Roy
We investigate the ferromagnetic-paramagnetic phase transition in coherently (Rabi) coupled Bose-Einstein condensates at zero and finite temperatures, exploring different routes to the transition by tuning the Rabi coupling or increasing the temperature at a fixed coupling. Using the Hartree-Fock-Bogoliubov theory within the Popov approximation, we map out the finite-temperature phase diagram of a three-dimensional homogeneous condensate and identify the critical line through the softening of the spin gap. Magnetization and the spin dispersion branch reveal the progressive suppression of the ferromagnetic order with increasing temperature. In quasi-one-dimensional harmonic traps, the transition, driven by Rabi coupling, is inferred through the softening of the spin breathing mode with its minimum shifting to lower coupling values with increasing temperature. Notably, the thermally driven transition causes monotonic hardening of all the spin modes. For both coupling and temperature-driven transition, the hybridized density modes in the ferromagnetic phase acquire more density character while approaching the critical point.
Quantum Gases (cond-mat.quant-gas)
11 pages, 8 figures
Spinon Mediation of Witness-Spin Dynamics and Ground State in Herbertsmithite
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Hiroto Takahashi, Jack Murphy, Mitikorn Wood-Thanan, Pascal Puphal, Miguel Angel Sanchez-Martinez, Fabian Jerzembeck, Chun-Chih Hsu, Jonathan Ward, Masahiko Isobe, Yosuke Matsumoto, Hidenori Takagi, Stephen J. Blundell, Michael R. Norman, Felix Flicker, J. C. Séamus Davis
The kagome lattice of spin-1/2 Cu atoms in herbertsmithite (ZnCu3(OH)6Cl2) may sustain a quantum spin liquid (QSL) state with spinon quasiparticles. Each kagome plane is separated from its homologues by a layer of spinless Zn atoms. Providentially, however, some spin-1/2 Cu atoms substitute randomly onto these inter-kagome Zn sites. We reconceptualize these ‘impurity’ atoms as quantum ‘witness-spins’, an exceptional new interrogative of the conjectured Z2-gauge-symmetric QSL state. Thus we introduce spin-noise spectroscopy to explore herbertsmithite witness-spin dynamics for QSL studies. It reveals the existence, slowing and intensification of spin noise, prefatory to a sharp transition at T\ast {\approx} 260 mK. Below T\ast the spin-noise power spectral density S_M({\omega},T) {\propto} {\omega}^{-{\alpha}(T)} stabilizes at {\alpha} {\approx} 1; the spin noise variance {\sigma}_M^2(T) diminishes precipitously; the ultra-low-field magnetic susceptibility {\chi}(T) undergoes a sharp transition into a phase exhibiting an Edwards-Anderson order-parameter and ultra-slow spin-state relaxation. A Z2 QSL theory of spinon-mediated witness-spin interactions corresponds best to all these experimental observations, predicting slowing and intensification of witness-spin fluctuations and noise spectrum S_M({\omega},T) with cooling, with a transition into a unique spinon-mediated phase signified by rapidly diminishing spin noise, with S_M({\omega},T) {\propto} {\omega}^{-1}, a sharp cusp in the DC magnetic susceptibility {\chi}(T), and the appearance of an Edwards-Anderson order-parameter. We rule out numerous other mechanisms for these effects, so that only spinon-mediation by either a Z2 or U(1) QSL is consistent with all present herbertsmithite empirics, with the former model providing a closer match to data.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
52 pages, 5 figures, 8 supplementary figures
Chirality reversal at finite magnetic impurity strength and local signatures of a topological phase transition
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-10-14 20:00 EDT
Ruiqi Xu, Arnab Seth, Itamar Kimchi
We study the honeycomb lattice with a single magnetic impurity modeled by adding imaginary next-nearest-neighbor hopping ih on a single hexagon. This Haldane defect gives a topological mass term to the gapless Dirac cones and generates chirality. For a small density of defects Neehus et al [arXiv:2405.19289] found that the system’s chirality reverses at a critical hc ~ 0.95 associated with an unexpected tri-critical point of Dirac fermions at zero defect density. We investigate this zero-density limit by analyzing a single defect and computing two experimentally relevant measures of chirality: (1) orbital magnetization via local Chern marker, a bulk probe of all occupied states; and (2) electronic currents of low-energy states. Both probes show a chirality reversal at a critical hc ~ 0.9–1. Motivated by this consistency we propose a defect-scale toy model whose low energy states reverse their chirality at hc’ ~ 0.87. Remarkably, the same pair of zero energy bound states also generate the critical point hc in the full impurity projected T-matrix. Our results show how the chirality reversal produced by an impurity can be observed either in local probes or in the global topology and suggest a possible role of the microscopic defect structure at the critical point.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 5 figures; appendix 4 pages, 5 figures
Comparing Symmetrized Determinant Neural Quantum States for the Hubbard Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-10-14 20:00 EDT
Louis Sharma, Ahmedeo Shokry, Rajah Nutakki, Olivier Simard, Michel Ferrero, Filippo Vicentini
Accurate simulations of the Hubbard model are crucial to understanding strongly correlated phenomena, where small energy differences between competing orders demand high numerical precision. In this work, Neural Quantum States are used to probe the strongly coupled and underdoped regime of the square-lattice Hubbard model. We systematically compare the Hidden Fermion Determinant State and the Jastrow-Backflow ansatz, parametrized by a Vision Transformer, finding that in practice, their accuracy is similar. We also test different symmetrization strategies, finding that output averaging yields the lowest energies, though it becomes costly for larger system sizes. On cylindrical systems, we consistently observe filled stripes. On the torus, our calculations display features consistent with a doped Mott insulator, including antiferromagnetic correlations and suppressed density fluctuations. Our results demonstrate both the promise and current challenges of neural quantum states for correlated fermions.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)