CMP Journal 2025-07-26
Statistics
Physical Review Letters: 5
Physical Review X: 2
arXiv: 63
Physical Review Letters
Search for Lepton-Flavor-Violating Decay Modes ${B}^{0}\rightarrow {K}_{S}^{0}{\tau }^{\pm{}}{\ell }^{\mp }$ with Hadronic $B$ Tagging at Belle and Belle II
Research article | Electroweak interaction | 2025-07-25 06:00 EDT
I. Adachi et al. (Belle and Belle II Collaborations)
We present the first search for the lepton-flavor-violating decay modes ${B}^{0}\rightarrow {K}{S}^{0}{\tau }^{\pm{}}{\ell }^{\mp }$ ($\ell =\mu ,e$) using the 711 and $365\text{ }\text{ }{\mathrm{fb}}^{- 1}$ data samples recorded by the Belle and Belle II detectors, respectively. We use a hadronic $B$-tagging technique to fully reconstruct a $B$ meson and search for signal decays in the system recoiling against the tagged meson, considering $\tau $ decays to either light leptons, one charged hadron, or one charged hadron and a neutral pion. We find no evidence for ${B}^{0}\rightarrow {K}{S}^{0}{\tau }^{\pm{}}{\ell }^{\mp }$ decays and set 90% confidence level upper limits on the branching fractions in the range of $[0.8,3.6]\times{}{10}^{- 5}$.
Phys. Rev. Lett. 135, 041801 (2025)
Electroweak interaction, Flavor changing neutral currents, Leptonic, semileptonic & radiative decays, Signatures with missing energy, Signatures with tau leptons, Bottom mesons, Hypothetical gauge bosons, Leptoquarks, Lepton colliders, Monte Carlo methods
Stellar Weak Rates of the $rp$-Process Waiting Points: Effects of Strong Magnetic Fields
Research article | Beta decay | 2025-07-25 06:00 EDT
Qi-Ye Hu, Long-Jun Wang, and Yang Sun
Incorporating microscopic nuclear-structure information into the discussion of bulk properties of astronomical objects such as neutron stars has always been a challenging issue in interdisciplinary nuclear astrophysics. Using the $rp$-process nucleosynthesis as an example, we studied the effective stellar ${\beta }^{+}$ and electron capture (EC) rates as well as the corresponding neutrino energy-loss rates of eight waiting-point (WP) nuclei with realistic stellar conditions and presence of strong magnetic fields. The relevant nuclear transition strengths are provided by the projected shell model. We have found that, on average, due to the magnetic field effect, the stellar weak rates can increase by more than an order of magnitude for all combinations of density and temperature, as well as in each of the WPs studied. We relate the onset field strength, at which the weak rates begin to increase, to nuclear structure quantities, $Q$ value or electronic chemical potential ${\mu }_{e}$. The enhanced weak rates may change considerably over the lifetime of WPs, thereby modifying the current understanding of the $rp$ process.
Phys. Rev. Lett. 135, 042702 (2025)
Beta decay, Nuclear astrophysics, Nuclear many-body theory, Nucleosynthesis in explosive environments
Emission of Acoustic Point Sources near an Interface
Research article | Acoustic modeling | 2025-07-25 06:00 EDT
Rong Zhou, Beibei Li, Liying Zhang, Yuecheng Shen, Hao Shen, Hongxing Xu, and Deng Pan
The emission of point sources is a cornerstone of wave-based physics, underpinning applications in optics and acoustics. While optical theories for point sources near interfaces are well established, a unified acoustic framework, modeled after its optical counterpart to provide cohesive insights into emission behaviors, remains underdeveloped. In this Letter, we extend the optical framework to acoustics, focusing on point sources near solid-fluid interfaces. Our theory predicts far-field patterns with richer features than their optical analogs, including multiple peaks and nonmonotonic supercritical emission dependence on source depth. For circularly polarized sources, we uncover depth-dependent transverse spin angular momentum in leaky Rayleigh waves, revealing opposite directions for distinct peaks. These findings shed new light on polarization related phenomena in acoustic near fields, bridging optics and acoustics while advancing the understanding of wave-matter interactions.
Phys. Rev. Lett. 135, 046204 (2025)
Acoustic modeling, Acoustic wave phenomena, Green’s function methods
Correlated Ligand Electrons in the Transition-Metal Oxide ${\mathrm{SrRuO}}_{3}$
Research article | Density of states | 2025-07-25 06:00 EDT
Yuichi Seki, Yuki K. Wakabayashi, Takahito Takeda, Kohdai Inagaki, Shin-ichi Fujimori, Yukiharu Takeda, Atsushi Fujimori, Yoshitaka Taniyasu, Hideki Yamamoto, Yoshiharu Krockenberger, Masaaki Tanaka, and Masaki Kobayashi
In transition-metal compounds, the transition-metal $d$ electrons play an important role in their physical properties; however, the effects of the electron correlation between the ligand $p$ electrons have not been clear yet. In this Letter, the $\mathrm{Ru}\text{ }4d$ and $\mathrm{O}\text{ }2p$ partial density of states (PDOS) in transition-metal oxide ${\mathrm{SrRuO}}_{3}$ involving Weyl fermions are investigated by resonant photoemission spectroscopy. The observations demonstrate that the $\mathrm{O}\text{ }2p$ PDOS is distorted from that predicted by first-principles calculations than the $\mathrm{Ru}\text{ }4d$ PDOS. The results indicate that the electron correlation in the ligand orbitals will be important to understand the electronic structure of the $p\text{- }d$ hybridized state in strongly correlated electron systems, even with topological states.
Phys. Rev. Lett. 135, 046402 (2025)
Density of states, Strongly correlated systems, Photoemission spectroscopy
Tuning Perpendicular Magnetic Anisotropy Compatible with Hybrid Improper Ferroelectricity via a Geometrical Route
Research article | Ferroelectricity | 2025-07-25 06:00 EDT
Yaoxiang Jiang, Donglai Xue, Jianguo Niu, Xiaohui Shi, Yanhui Liu, Cong Wang, Weibo Gao, and Shifeng Zhao
Achieving effective manipulation of perpendicular magnetic anisotropy within the coupling of ferroelectricity remains an intricate challenge, yet it is crucial in the electric-field control of the excitation and propagation of magnonic spin-polarization currents. Perpendicularly magnetized structures are normally inhibited to varying degrees in a polarization switching path due to the intrinsic chemical incompatibility of electronic mechanisms for single-phase multiferroics. Here, we demonstrate a geometrically coupling strategy of oxygen octahedral distortions to regulate hybrid improper ferroelectricity and perpendicular magnetic anisotropy coupled in double-perovskite superlattice films. The geometrical ferroic mechanisms lead to a coexistence of strong ferromagnetism and room-temperature ferroelectricity, particularly with a perpendicularly magnetized structure. Based on the perturbation theory and Arrott-Noakes equation, it is revealed that such magnetic anisotropy originates from spin-orbit coupling and is regulated by the crystal-field splitting from Jahn-Teller distortion in a stable mean-field exchange model, compatible with polarization changes. Our Letter provides a geometrical route to design and regulate the coupling ferroic orders of perpendicular magnetic anisotropy and ferroelectricity.
Phys. Rev. Lett. 135, 046801 (2025)
Ferroelectricity, Magnetic anisotropy, Perovskites, Superlattices, Density functional theory, Scanning tunneling microscopy
Physical Review X
Bolometric Superconducting Optical Nanoscopy (BOSON)
Research article | Critical current | 2025-07-25 06:00 EDT
Ran Jing, Boyi Zhou, Dingchen Kang, Wenjun Zheng, Zijian Zhou, Heng Wang, Xinzhong Chen, Juntao Yao, Bing Cheng, Ji-Hoon Park, Lukas Wehmeier, Zhenbing Dai, Shoujing Chen, Christopher D. Prainito, G. L. Carr, Ilya Charaev, Denis Bandurin, Genda Gu, Qiang Li, Karl K. Berggren, D. N. Basov, Xu Du, and Mengkun Liu
BOSON–an ultralow-power optical nanoscopy technique using superconducting sensors–enables high-resolution imaging of superconductor transition edges as well as weak polaritonic signals, opening new frontiers in quantum sensing.
Phys. Rev. X 15, 031027 (2025)
Critical current, Methods in superconductivity, Photocurrent, Photoinduced effect, Polaritons, Superconducting phase transition, Superconductivity, Thermoelectric effects, Transition temperature, Boron nitride, Nanotechnology, Superconducting devices, Superconductors, Weak links, Atomic force microscopy, Bolometers, Imaging & optical processing, Infrared spectroscopy, Infrared techniques, Liquid helium cooling, Optical nanoscopy, Optical techniques, Single-photon detectors
Autonomous Stabilization of Floquet States Using Static Dissipation
Research article | Quantum control | 2025-07-25 06:00 EDT
Martin Ritter, David M. Long, Qianao Yue, Anushya Chandran, and Alicia J. Kollár
Floquet engineering can boost quantum device capabilities, and, surprisingly, adding controlled loss can reduce unwanted heating and errors, making quantum systems more stable and effective.
Phys. Rev. X 15, 031028 (2025)
Quantum control, Quantum engineering
arXiv
Hydrodynamic Theory of Two-dimensional Chiral Malthusian Flocks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-25 20:00 EDT
Leiming Chen, Chiu Fan Lee, John Toner
We study the hydrodynamic behavior of two-dimensional chiral dry Malthusian flocks; that is, chiral polar-ordered active matter with neither number nor momentum conservation. We show that, in the absence of fluctuations, such systems generically form a ``time cholesteric”, in which the velocity of the entire system rotates uniformly at a fixed frequency b. Fluctuations about this state belong to the universality class of (2+1)-Kardar-Parisi-Zhang (KPZ) equation, which implies short-ranged orientational order in the hydrodynamic limit. We then show that, in the limit of weak chirality, the hydrodynamics of a system with reasonable size is expected to governed by the linear regime of the KPZ equation, exhibiting quasi-long-ranged orientational order. Our predictions for the velocity and number density correlations are testable in both simulations and experiments.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
38 pages, 4 figures, 1 table
Exact results on the hydrodynamics of certain kinetically-constrained hopping processes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-25 20:00 EDT
Adam J. McRoberts, Vadim Oganesyan, Antonello Scardicchio
We consider a model of interacting random walkers on a triangular chain and triangular lattice, where a particle can move only if the other two sites of the triangle are unoccupied – a kinetically-constrained hopping process (KCHP) recently introduced in the context of non-linear diffusion cascades. Using a classical-to-quantum mapping – where the rate matrix of the stochastic KCHP corresponds to a spin Hamiltonian, and the equilibrium probability distribution to the quantum ground state – we develop a systematic perturbation theory to calculate the diffusion constant; the hydrodynamics of the KCHPs is determined by the low-energy properties of the spin Hamiltonian, which we analyse with the standard Holstein-Primakoff spin-wave expansion.
For the triangular hopping we consider, we show that \textit{non-interacting} spin-wave theory predicts the \textit{exact} diffusion constant. We conjecture this holds for all KCHPs with (i) hard-core occupancy, (ii) parity-symmetry, and (iii) where the hopping processes are given by three-site gates – that is, where hopping between two sites is conditioned on the occupancy of a third. We further show that there are corrections to the diffusion constant when the KCHP is described by \textit{four}-site gates, which we calculate at leading order in the semi-classical $ 1/S$ expansion. We support all these conclusions with numerical simulations.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
5 + 11 pages
Quantum Geometric Injection and Shift Optical Forces Drive Coherent Phonons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
J. Luke Pimlott, Habib Rostami
We identify {\em injection} and {\em shift} rectified Raman forces, which are phononic counterparts of the photogalvanic effect, that drive lattice vibrations and trigger transient emergent properties. These forces are governed by the {\em quantum geometric tensor}, a {\em phononic shift vector}, and interband asymmetries in the electron-phonon coupling. The injection force acts displacively, while – unlike conventional impulsive mechanisms – the shift force emerges impulsively in the resonant interband absorbing regime when time-reversal symmetry is broken. Using the bilayer Haldane model, we quantify the injection and shift forces acting on interlayer shear phonons through both analytical and numerical methods. Strikingly, we reveal strong tunability, both in magnitude and direction, of the rectified forces by varying the driving frequency and magnetic flux, uncovering a distinct quantum geometric mechanism for ultrafast and coherent manipulation of quantum materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6+11 pages, 3+3 figures
Higher Chern bands in helical homotrilayer transition metal dichalcogenides
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Jungho Daniel Choi, Nicolás Morales-Durán, Yves H. Kwan, Andrew J. Millis, Nicolas Regnault, Daniele Guerci
We propose helically twisted homotrilayer transition metal dichalcogenides as a platform for realizing correlated topological phases of matter with higher and tunable Chern numbers. We show that a clear separation of scales emerges for small twist angles, allowing us to derive a low-energy continuum model that captures the physics within moiré-scale domains. We identify regimes of twist angle and displacement field for which the highest-lying hole band is isolated from other bands and is topological with $ K$ -valley Chern number $ C=-2$ . We demonstrate that varying the displacement field can induce a transition from $ C=-2$ to $ C=-1$ , as well as from a topologically trivial band to a $ C=-1$ band. We derive an effective tight-binding description for a high-symmetry stacking domain which is valid for a wide range of twist angles, and we show that the $ C=-2$ band can remain stable at filling fraction $ \nu=-1$ in the presence of interactions in Hartree-Fock calculations.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
30 pages, 19 figures
Proximity-induced flat bands and topological properties in a decorated diamond chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
K Shivanand Thakur, Vihodi Theuno, Amrita Mukherjee, Biplab Pal
In the present study, we propose a unique scheme to generate and control multiple flat bands in a decorated diamond chain by using a strain-induced proximity effect between the diagonal sites of each diamond plaquette. This is in complete contrast to the conventional diamond chain, in which the interplay between the lattice topology and an external magnetic flux leads to an extreme localization of the single-particle states, producing the flat bands in the energy spectrum. Such a strain-induced proximity effect will enable us to systematically control one of the diagonal hoppings in the decorated diamond chain, which will lead to the formation of both gapless and gapped flat bands in the energy spectrum. These gapless or gapped flat bands have been corroborated by the computation of the compact localized states amplitude distribution as well as the density of states of the system using a real space calculation. We have also shown that these flat bands are robust against the introduction of small amounts of random onsite disorder in the system. In addition to this, we have also classified the nontrivial topological properties of the system by calculating the winding numbers and edge states for the gapped energy spectrum. These findings could be easily realized experimentally using the laser-induced photonic lattice platforms.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
8 pages, 8 figures, Comments are welcome
Magnon topology driven by altermagnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
Subhankar Khatua, Volodymyr P. Kravchuk, Kostiantyn V. Yershov, Jeroen van den Brink
Altermagnets present a new class of fully compensated collinear magnetic order, where the two sublattices are not related merely by time-reversal combined with lattice translation or inversion, but require an additional lattice rotation. This distinctive symmetry leads to a characteristic splitting of the magnon bands; however the splitting is only partial – residual degeneracies persist along certain lines in the Brillouin zone as a consequence of the underlying altermagnetic rotation. We consider a two-dimensional $ d$ -wave altermagnetic spin model on the checkerboard lattice and introduce additional interactions such as an external magnetic field and Dzyaloshinskii-Moriya interactions, that lift these degeneracies. The resulting magnon bands become fully gapped and acquire non-trivial topology, characterized by nonzero Chern numbers. We demonstrate the crucial role of altermagnetism for the generation of the Berry curvature. As a direct consequence of the topological magnons, we find finite thermal Hall conductivity $ \kappa_{xy}$ , which exhibits a characteristic low-temperature scaling, $ \kappa_{xy}\propto T^4$ . Moreover, $ \kappa_{xy}$ changes sign under reversal of the magnetic field, exhibiting a sharp jump across zero field at low temperatures. We also demonstrate topologically protected chiral edge modes in a finite strip geometry.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 9 figures, 2 videos in the Supplemental Material
Two-dimensional nonlinear dynamical response of the magnetoelectrically driven dimerized spin-$1{/}2$ chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
A study of the dynamical two-dimensional (2D) nonlinear response of the dimerized spin-$ 1{/}2$ chain to external electric fields is presented. The coupling of the spin system to those fields is set to arise from the inverse Dzyaloshinskii-Moriya interaction. In the XY-limit, we provide analytical expressions for the second-order nonlinear dynamical response function. Apart from multi spinon continua, this response displays a strong antidiagonal, i.e. galvanoelectric, feature in the 2D frequency plane. This allows to read off scattering rates of the fractional spinon excitations. For the XXZ-case, we focus on the interaction-driven renormalization of the light-matter coupling by considering vertex corrections which are induced by the zz-exchange. We show this renormalization to modify the spinon joint density of states significantly, potentially allowing for the formation of in-gap bound states. As a result, the vertex corrected light-matter coupling can induce a dramatic spectral weight transfer to lower energies for the dynamical response function within the 2D frequency plane.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 5 figures
Hydrodynamics without Averaging – a Hard Rods Study
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-25 20:00 EDT
On the example of the integrable hard rods model we study the quality of the (generalized) hydrodynamic approximation on a single coarse-grained sample. This is opposed to the traditional approach which averages over an appropriate local equilibrium state. While mathematically more ambiguous, a major advantage of the new approach is that it allows us to disentangle intrinsic diffusion from `diffusion from convection’ effects. For the hard rods we find intrinsic diffusion is absent, which agrees with and clarifies recent findings. Interestingly, the results also apply to not locally thermal states, demonstrating that hydrodynamics (in this model) does not require the assumption of local equilibrium.
Statistical Mechanics (cond-mat.stat-mech)
42 pages, 4 figures
Comparative analysis of plasmon modes in layered Lindhard metals and strange metals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
Niels de Vries, Jin Chen, Eric Hoglund, Xuefei Guo, Dipanjan Chaudhuri, Jordan Hachtel, Peter Abbamonte
The enigmatic strange metal remains one of the central unsolved problems of 21st century science. Understanding this phase of matter requires knowledge of the momentum- and energy-resolved dynamic charge susceptibility, $ \chi(q,\omega)$ , especially at finite momentum. Inelastic electron scattering (EELS), performed in either transmission (T-EELS) or reflection (R-EELS) geometries, is a powerful probe of $ \chi(q,\omega)$ . For the prototypical strange metal Bi$ _2$ Sr$ _2$ CaCu$ _2$ O$ _{8+x}$ , T-EELS, R-EELS, and infrared (IR) spectroscopy agree at $ q \sim 0$ , all revealing a highly damped plasmon near 1 eV. At larger $ q$ , however, EELS results show unresolved discrepancies. Since IR data are highly reproducible, it is advantageous to use IR data to calculate what the expected EELS response should be at modest $ q$ . Building on prior R-EELS work [J. Chen \textit{et al.}, Phys. Rev. B. \textbf{109}, 045108 (2024)], we extend this approach to T-EELS for finite stacks of metallic layers, comparing a “textbook” Lindhard metal to a strange metal. In the Lindhard case, the low-$ q$ response is dominated by long-lived, standing wave plasmon modes arising from interlayer Coulomb coupling, with in-plane dispersions that resemble the well-known Fetter modes of layered metals. This behavior depends only on the geometry and the long-ranged nature of the Coulomb interaction, and is largely insensitive to layer details. At larger $ q$ , the response reflects the microscopic properties of individual layers. For the strange metal, calculations based on IR data predict a highly damped plasmon with weak dispersion and no distinct surface mode. While our results match IR and R-EELS at low $ q$ , they do not reproduce any published EELS spectra at large $ q$ , highlighting unresolved discrepancies that demand further experimental investigation.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
10 pages, 4 figures
Sb2S3 and GaAs Absorber Layer-based Quantum Dot Solar Cells with Cadmium Telluride-based HTL: A Comparative Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Sayak Banerjee (1 and 2), Anupam Chetia (1), Satyajit Sahu (1) ((1) Department of Physics, Indian Institute of Technology, Jodhpur, Rajasthan, India-342037, (2) Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Jodhpur, Rajasthan, India)
Quantum dot solar cells (QDSC) are widely acknowledged to be one of the best solar energy harvesting devices in the present world. Absorber layer is a core component of a QDSC with a strong influence on its operational efficiency. Hence, we choose to undertake a comparative study of two QDSC having different QD absorber layers: Sb2S3 and GaAs with the motive to identify the better absorber layer material. The numerical analysis has been carried out using SCAPS-1D (Solar Cell Capacitance Simulator-1D). The structure of the QDSCs under study are: FTO/TiO2/CdS/Sb2S3/CuI/C and FTO/TiO2/CdS/GaAs/CuI/C. Critical parameters, including temperature, back contact work function, series and shunt resistances, were meticulously adjusted in the simulations, demonstrating that the maximum efficiency attained by Sb2S3 and GaAs absorber layer based QDSC is 15.94% and 26.95% respectively indicating GaAs-QD to be a better absorber layer material for a QDSC.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Extending exciton and trion lifetimes in MoSe$_{2}$ with a nanoscale plasmonic cavity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Grace H. Chen, Anchita Addhya, Ian N. Hammock, Philip Kim, Alexander A. High
Excitons in transition metal dichalcogenides (TMDs) have extremely short, picosecond-scale lifetimes which hinders exciton thermalization, limits the emergence of collective coherence, and reduces exciton transport in optoelectronic devices. In this work, we explore an all-optical pathway to extend exciton lifetimes by placing MoSe$ _2$ in a deep-subwavelength Fabry-Perot silver cavity. The cavity structure is designed to suppress radiative recombination from in-plane optical dipoles, such as bright excitons and trions. We observe a consistent decrease in photoluminescence (PL) linewidths of excitons and trions (1 nm), along with a corresponding lifetime increase (10 ps). We confirm the experimental observations arise purely from exciton-cavity interactions-etching back the top silver layer returns the PL linewidth and lifetimes return to their original values. Our study offers a pathway to engineer excited state lifetimes in 2D materials which can be utilized for studies of optically dark excitons and have potential applications for novel optoelectronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 3 figures
Differential Crosslinking and Contractile Motors Drive Nuclear Chromatin Compaction
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-25 20:00 EDT
Ligesh Theeyancheri, Edward J. Banigan, J. M. Schwarz
During interphase, a typical cell nucleus features spatial compartmentalization of transcriptionally active euchromatin and repressed heterochromatin domains. In conventional nuclear organization, euchromatin predominantly occupies the nuclear interior, while heterochromatin, which is approximately 50% more dense than euchromatin, is positioned near the nuclear periphery. Peripheral chromatin organization can be further modulated by the nuclear lamina, which is itself a deformable structure. While a number of biophysical mechanisms for compartmentalization within rigid nuclei have been explored, we study a chromatin model consisting of an active, crosslinked polymer tethered to a deformable, polymeric lamina shell. Contractile motors, the deformability of the shell, and the spatial distribution of crosslinks all play pivotal roles in this compartmentalization. We find that a radial crosslink density distribution, even with a small linear differential of higher crosslinking density at the edge of the nucleus, combined with contractile motor activity, drives genomic segregation, in agreement with experimental observations. This arises from contractile motors preferentially drawing crosslinks into their vicinity at the nuclear periphery, forming high-density domains that promote heterochromatin formation. We also find an increased stiffness of nuclear wrinkles given the preferential heterochromatin compaction below the lamina shell, which is consistent with instantaneous nuclear stiffening under applied nanoindentation. We conclude with the potential for experimental validation of our model predictions.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
18 pages, 7 figures, and Supporting information
Analysis of Fe and Co binary catalysts in chemical vapor deposition growth of single-walled carbon nanotubes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Qingmei Hu, Ya Feng, Wanyu Dai, Daisuke Asa, Daniel Hedman, Aina Fito Parera, Yixi Yao, Yongjia Zheng, Kaoru Hisama, Gunjan Auti, Hirofumi Daiguji, Christophe Bichara, Shohei Chiashi, Yan Li, Wim Wenseleers, Dmitry Levshov, Sofie Cambre, Keigo Otsuka, Rong Xiang, Shigeo Maruyama
Metal catalysts play a pivotal role in the growth of single-walled carbon nanotubes (SWCNTs), with binary metallic catalysts emerging as an efficient SWCNT synthesis strategy. Among these, iron (Fe), cobalt (Co), and their alloys are particularly effective. However, prior studies have predominantly employed Fe–Co alloy catalysts with fixed atomic ratios as well as unchanged chemical vapor deposition (CVD) conditions, leaving the influence of variable Fe–Co compositions and CVD growth parameters on SWCNT synthesis poorly understood. This study focuses on the role of Fe–Co catalyst ratios, with the aim of elucidating the distinct contributions of Fe and Co atoms in the growth of SWCNTs. By systematically exploring a wide range of Fe–Co ratios and growth conditions, we identified Fe$ _{0.75}$ Co$ _{0.25}$ as a highly efficient binary catalyst at 850$ ^\circ$ C, primarily forming catalyst clusters with diameters of 2.5–6nm and yielding SWCNTs with diameters ranging from 0.9–1.1nm. On the other hand, Fe$ _{0}$ Co$ _{1}$ exhibited higher catalytic activity at 600$ ^\circ$ C, generating smaller catalyst clusters of 1.5–5nm and producing SWCNTs with reduced diameters of about 0.6–0.9nm. Transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS) analyses reveal that high SWCNT yields correlate with the formation of uniformly sized Fe–Co catalyst particles with surface-segregated Co that optimizes carbon solubility. Molecular dynamics (MD) simulations further corroborate these findings, demonstrating that the structure and melting behavior of Fe$ _x$ Co$ _{1-x}$ clusters depend on cluster size and composition.
Materials Science (cond-mat.mtrl-sci)
Pages 1 to 31 contain the main content, while pages 31 to 59 are the supplementary materials
Unlocking Surfactant Synergies for Fluorine Replacements: A Microfluidic Exploration of Emulsion Stability and Coalescence Dynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-25 20:00 EDT
Fluorinated surfactants are widely utilized in various applications, including firefighting foams, coatings, and lubricants. Their wide utility is due to their unique properties, such as their ability to effectively lower surface/interfacial tension. However, the excessive use of fluorinated surfactants has raised environmental and health concerns due to their persistence in the environment and potential toxicity. The need for effective and sustainable surfactant replacements has therefore become critical. Our study investigates alternative surfactants mixtures that have been proposed to replicate the performance of traditional fluorinated surfactants, while minimizing environmental impact. Here, we study the stability of thin aqueous liquid bridges found in water in oil emulsions, with surfactant mixtures shown to provide synergistic fire suppression in fluorine-free fire fighting foams. Binary surfactant-water solutions of TritonX-100, Glucopon 215, Dow 502W were used, in addition to a ternary surfactant-surfactant-water mixtures of Glucopon 215 and Dow502W. Emulsion stability is assessed using a microfluidic device designed to measure the coalescence frequency. Coalescence frequency is measured as a function of total flow rate and surfactant concentration. A non-monotonic trend of coalescence frequency with flow rate is found for all the surfactants used. In addition, a non-dimensional frequency is introduced and is found to decrease with the Capillary number. The coalescence frequency of the surfactant mixture is found to be close to that of Dow502W, suggesting a synergistic behavior between Glucopon215 and Dow502W, even with less of the siloxane surfactant present in the formulation. This behavior highlights the potential for pairing slower hydrocarbon surfactants with faster siloxane surfactants to achieve an effective alternative stabilizing agent for fluorine free formulation.
Soft Condensed Matter (cond-mat.soft)
Correlation effects in one-dimensional metallic quantum wires under various confinements
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-25 20:00 EDT
Vidit Gangwar, Vinod Ashokan, Ankush Girdhar, Klaus Morawetz, N. D. Drummond, K. N. Pathak
Dynamical response theory is used to investigate various transverse confinements on electron correlations in the ground state of a ferromagnetic one-dimensional quantum wire for different wire widths $ b$ and density parameters $ r_{\rm s}$ . Using the first-order random phase approximation (FRPA), which provides the ground state structure beyond the random phase approximation, we compute the structure factor, pair-correlation function, correlation energy, and ground-state energy. The correlation energy depends on the choice of confinement model and hence effective electron-electron interaction. For the ultrathin wire ($ b\rightarrow 0$ ) in the high-density limit, the correlation energy for transverse confinement models $ V_1(q)$ (harmonic), $ V_2(q)$ (cylindrical), and $ V_5(q)$ (harmonic-delta) approaches $ \epsilon_{\rm c}(r_{\rm s})= - \pi^2/360 \sim -0.02741$ a.u., which agrees with the exact results in this limit [J. Chem. Phys. 138, 064108 (2013); Phys. Rev. B 101, 075130 (2020)]. For at least these three confinement potentials, the one-dimensional Coulomb potential can be regularized at interparticle distance $ x=0$ to yield the same correlation energy. In contrast, $ V_3(q)$ (infinite square well), $ V_4(q)$ (infinite square-infinite triangular well), and $ V_6(q)$ (infinite square-delta well), do not approach the same high-density limit; instead, the correlation energy tends to $ \epsilon_{\rm c} \sim -0.03002$ a.u. The ground-state properties obtained from the FRPA are compared with quantum Monte Carlo results. The peak height in the static structure factor at $ k=2k_{\rm F}$ depends significantly on the confinement model. These peaks are fitted with a function based on our finite wire-width theory demonstrating good agreement with FRPA.
Quantum Gases (cond-mat.quant-gas)
Computation and Sensitivity Analysis of the Deformation-Gradient Tensor Reconstruction in Dark-Field X-ray Microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Brinthan Kanesalingam, Darshan Chalise, Carsten Detlefs, Leora Dresselhaus-Marais
Spatially resolved strain measurements are crucial to understanding the properties of engineering materials. Although strain measurements utilizing techniques such as transmission electron microscopy and electron backscatter diffraction offer high spatial resolution, they are limited to surface or thin samples. X-ray diffraction methods, including Bragg Coherent Diffraction Imaging and X-ray topography, enable strain measurements deep inside bulk materials but face challenges in simultaneously achieving both high spatial resolution and large field-of-view. Dark-field X-ray Microscopy (DFXM) offers a promising solution with its ability to image bulk crystals at the nanoscale while offering a field-of-view approaching a few hundred $ \mu$ m. However, an inverse modeling framework to explicitly relate the angular shifts in DFXM to the strain and lattice rotation tensors is lacking. In this paper, we develop such an inverse modeling formalism. Using the oblique diffraction geometry, enabling access to noncoplanar symmetry-equivalent reflections, we demonstrate that the reconstruction of the full deformation gradient tensor ($ \mathbf{F^{(g)}}$ ) is possible. We also develop the computational framework to both forward calculate the anticipated angular shifts and reconstruct the average $ \mathbf{F^{(g)}}$ for an individual pixel from DFXM experiments. Finally, utilizing the established formalism and computational framework, we present methods for sensitivity analysis to relate individual components of the rotation or strain tensor to specific angles of DFXM. The developed sensitivity analysis also enables explicit computation of the errors associated with the reconstruction of each component. The formalism, the computational framework, and the sensitivity analysis established in this paper should assist both the interpretation of past DFXM experiments and the design of future DFXM experiments.
Materials Science (cond-mat.mtrl-sci)
Efficient $G_0W_0$ and BSE calculations of heterostructures within an all-electron framework
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Maximilian Schebek, Ignacio Gonzalez Oliva, Claudia Draxl
The combination of two-dimensional materials into heterostructures offers new opportunities for the design of optoelectronic devices with tunable properties. However, computing electronic and optical properties of such systems using state-of-the-art methodology is challenging due to their large unit cells. This is in particular so for highly-precise all-electron calculations within the framework of many-body perturbation theory, which come with high computational costs. Here, we extend an approach that allows for the efficient calculation of the non-interacting polarizability, previously developed for planewave basis sets, to the (linearized) augmented planewave (L)APW method. This approach is based on an additive ansatz, which computes and superposes the polarizabilities of the individual components in their respective unit cells. We implement this formalism in the $ G_0W_0$ module of the exciting code and implement an analogous approach for BSE calculations. This allows the calculation of highly-precise optical spectra at low cost. So-obtained results of the quasi-particle band structure and optical spectra are demonstrated for bilayer WSe$ _2$ and pyridine@MoS$ _2$ in comparison with exact reference calculations.
Materials Science (cond-mat.mtrl-sci)
Tuning chiral anomaly signature in a Dirac semimetal via fast-ion implantation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Manasi Mandal, Eunbi Rha, Abhijatmedhi Chotrattanapituk, Denisse Córdova Carrizales, Alexander Lygo, Kevin B. Woller, Mouyang Cheng, Ryotaro Okabe, Guomin Zhu, Kiran Mak, Chu-Liang Fu, Chuhang Liu, Lijun Wu, Yimei Zhu, Susanne Stemmer, Mingda Li
Cd$ _3$ As$ _2$ is a prototypical Dirac semimetal that hosts a chiral anomaly and thereby functions as a platform to test high-energy physics hypotheses and to realize energy efficient applications. Here we use a combination of accelerator-based fast ion implantation and theory-driven planning to enhance the negative longitudinal magnetoresistance (NLMR)–a signature of a chiral anomaly–in Nb-doped Cd$ _3$ As$ _2$ thin films. High-energy ion implantation is commonly used to investigate semiconductors and nuclear materials but is rarely employed to study quantum materials. We use electrical transport and transmission electron microscopy to characterize the NLMR and the crystallinity of Nb-doped Cd$ _3$ As$ _2$ thin films. We find surface-doped Nb-Cd$ _3$ As$ _2$ thin films display a maximum NLMR around $ B = 7$ T and bulk-doped Nb-Cd$ _3$ As$ _2$ thin films display a maximum NLMR over $ B = 9$ T–all while maintaining crystallinity. This is more than a 100% relative enhancement of the maximum NLMR compared to pristine Cd$ _3$ As$ _2$ thin films ($ B = 4$ T). Our work demonstrates the potential of high-energy ion implantation as a practical route to realize chiralitronic functionalities in topological semimetals.
Materials Science (cond-mat.mtrl-sci)
Black-box optimization using factorization and Ising machines
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-25 20:00 EDT
Ryo Tamura, Yuya Seki, Yuki Minamoto, Koki Kitai, Yoshiki Matsuda, Shu Tanaka, Koji Tsuda
Black-box optimization (BBO) is used in materials design, drug discovery, and hyperparameter tuning in machine learning. The world is experiencing several of these problems. In this review, a factorization machine with quantum annealing or with quadratic-optimization annealing (FMQA) algorithm to realize fast computations of BBO using Ising machines (IMs) is discussed. The FMQA algorithm uses a factorization machine (FM) as a surrogate model for BBO. The FM model can be directly transformed into a quadratic unconstrained binary optimization model that can be solved using IMs. This makes it possible to optimize the acquisition function in BBO, which is a difficult task using conventional methods without IMs. Consequently, it has the advantage of handling large BBO problems. To be able to perform BBO with the FMQA algorithm immediately, we introduce the FMQA algorithm along with Python packages to run it. In addition, we review examples of applications of the FMQA algorithm in various fields, including physics, chemistry, materials science, and social sciences. These successful examples include binary and integer optimization problems, as well as more general optimization problems involving graphs, networks, and strings, using a binary variational autoencoder. We believe that BBO using the FMQA algorithm will become a key technology in IMs including quantum annealers.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
23 pages, 7 figures
Compositional Tuning in NaxAlB14 via Diffusion Control
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Mihiro Hoshino, Suguru Iwasaki, Shigeto Hirai, Yoshihiko Ihara, Tohru Sugahara, Haruhiko Morito, Masaya Fujioka
A uniform Na distribution in NaxAlB14 was achieved using high-pressure diffusion control (HPDC), which promotes Na deintercalation through enhanced diffusion under high pressure, combined with post-annealing. NaxAlB14 with a non-stoichiometric Na composition is thermodynamically metastable, and conventional solid-state reactions with adjusted starting compositions typically result in the formation of stoichiometric NaAlB14 and side products. While HPDC alone typically leads to concentration gradients, intentionally halting the Na removal process before complete extraction, followed by annealing, enabled a uniform composition across the bulk. This allowed structural and electronic properties to be examined over a wide range of Na concentrations. As Na content decreased, electrical conductivity increased, and the optical band gap narrowed. NMR measurements showed an increase in the density of states at the Fermi level, consistent with DFT calculations predicting boron-related in-gap states. Boron vacancies at specific sites were found to generate deep levels near the band gap center, which can explain experimentally observed optical gap reduction. These results demonstrate that diffusion-controlling methods can be effectively applied to synthesize metastable compounds with tunable compositions in covalent frameworks. Furthermore, they provide a foundation for designing functional boride-based materials with adjustable electronic properties by controlling Na extraction and inducing defect formation.
Materials Science (cond-mat.mtrl-sci)
14 pages, 4 figures
Ultra-clean interface between high k dielectric and 2D MoS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Han Yan, Yan Wang, Yang Li, Dibya Phuyal, Lixin Liu, Hailing Guo, Yuzheng Guo, Tien-Lin Lee, Min Hyuk Kim, Hu Young Jeong, Manish Chhowalla
Atomically thin transition metal dichalcogenides (TMDs) are promising candidates for next-generation transistor channels due to their superior scaling properties. However, the integration of ultra-thin gate dielectrics remains a challenge, as conventional oxides such as SiO2, Al2O3, and HfO2 tend to unintentionally dope 2D TMDs and introduce interfacial defect states, leading to undesirable field-effect transistor (FET) performance and unstable threshold voltages. Here, we demonstrate that zirconium oxide (ZrO2), a high-k dielectric compatible with semiconductor processing, forms an ultra-clean interface with monolayer MoS2. Using soft and hard X-ray photoelectron spectroscopy and density functional theory, we find that ZrO2 does not measurably interact with MoS2, in contrast to significant doping observed for SiO2 and HfO2 substrates. As a result, back-gated monolayer MoS2 FETs fabricated with ZrO2 dielectrics exhibit stable and positive threshold voltages (0.36 plus/minus 0.3 V), low subthreshold swing (75 mV per decade), and high ON currents exceeding 400 microamperes. We further demonstrate p-type WSe2 FETs with ON currents greater than 200 microamperes per micrometer by suppressing electron doping with ZrO2 dielectrics. Atomic-resolution imaging confirms a defect-free ZrO2/MoS2 interface, which enables top-gate FETs with an equivalent oxide thickness of 0.86 nanometers and subthreshold swing of 80 mV per decade. Moreover, the ultraclean ZrO2/MoS2 interface allows for effective threshold voltage modulation in top-gate FETs via gate metal work function engineering. These findings establish ZrO2 as a highly promising, industry-compatible high-k dielectric for scalable 2D TMD-based electronics.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
30 pages
Defect-Assisted Recombination in Semiconductors and Photovoltaic Device Parameters from First Principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Jiban Kangsabanik, Kristian S. Thygesen
We introduce a method to calculate defect-assisted Shockley-Read-Hall (SRH) recombination rates in imperfect semiconductors from first principles. The method accounts for the steady state recombination dynamics under given non-equilibrium conditions (split quasi Fermi levels), by invoking a full solution to the rate equations describing transitions across the band gap via all possible charge states of the defect. Transition rates due to radiative and non-radiative multi-phonon emission processes are calculated from first principles. The method is used to evaluate the effect of selected defects on the photovoltaic device parameters of seven emergent photovoltaic semiconductors. These examples clearly highlight the limitations of commonly employed approximations to the recombination dynamics. Our work advances the description and understanding of defect-induced losses in photovoltaics and provides a basis for developing the important concept of defect tolerant semiconductors and to discover high-performance photovoltaic materials computationally.
Materials Science (cond-mat.mtrl-sci)
Out-of-plane ferroelectricity, magnetoelectric coupling and persistent spin texture in two-dimensional multiferroics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Ying Zhou, Cheng-Ao Ji, Shuai Dong, Xuezeng Lu
Two dimensional multiferroics with out of plane ferroelectricity hold significant promise for miniaturized magnetoelectric spin-orbit transistors, yet systems combining robust ferroelectricity and strong magnetoelectric coupling are exceedingly rare. Here, we demonstrate that epitaxial strain stabilizes out of plane ferroelectricity in exfoliated two dimensional Ruddlesden Popper derivatives. The hybrid improper ferroelectric Pc phase transitions to a competing P21 phase with purely in plane polarization upon switching, accompanied by a 90 degree rotation of weak ferromagnetism. Crucially, the Pc phase exhibits altermagnetism, while P21 displays full Brillouin zone band splitting, with persistent spin textures rotating 90 degree at the phase boundary. This work establishes a pathway to engineer two dimensional multiferroics that integrate vertical polarization, magnetoelectric coupling, and switchable spin textures, key features for next generation spintronic devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 5 figures
Multipole order in two-dimensional altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
We theoretically investigate the magnetic-multipole orders in two-dimensional (2D) altermagnets, focusing on two representative models: a generic minimal three-site model, and a four-site model representative of monolayer FeSe. We construct low-energy effective Hamiltonians for both systems and calculate their respective multipole indicators to characterize the underlying magnetic order. Our analysis reveals an intriguing contrast between the two systems. We find that the generic minimal model exhibits the expected non-zero magnetic-octupole order. In the monolayer-FeSe model, however, the magnetic-octupole order vanishes globally, and a magnetic-hexadecapole order is present instead. The emergence of altermagnetic splitting in the band structure then arises via the interplay with a sublattice-isospin degree of freedom. Our work demonstrates how the classification and comprehensive understanding of 2D altermagnetic materials transcends bulk descriptions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 6 figures
Nitrogen-vacancy centre formation via local femto-second laser annealing of diamond
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Davin Yue Ming Peng, Alexander J Healey, Rebecca Griffin, Benjamin Cumming, Hiroshi Abe, Takeshi Ohshima, Alastair Stacey, Brant C Gibson, Brett C Johnson, Philipp Reineck
Emerging quantum technologies based on the nitrogen-vacancy (NV) centre in diamond require carefully engineered material with controlled defect density, optimised NV formation processes, and minimal crystal strain. The choice of NV generation technique plays a crucial role in determining the quality and performance of these centres. In this work, we investigate NV centre formation in nitrogen-doped diamond using femtosecond (fs) laser processing. We systematically examine the effect of laser pulse energy on NV production and quality using photoluminescence and optically detected magnetic resonance measurements. We also probe the role of pre-existing lattice defects formed by electron irradiation and consider defect evolution over extended dwell times. Finally, we are able to identify a regime where the main action of the fs-laser is to diffuse rather than create vacancies. This local annealing capability expands the toolkit for tailored NV production and presents opportunities for fine tuning defect populations.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Anomalous increasing super reflectance in chiral matter
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-25 20:00 EDT
Pedro D. S. Silva, Alex Q. Costa, Ronald A. Pereira, Manoel M. Ferreira Jr
Magnetic and anomalous Hall conductivities induce anomalous transport features and novel optical phenomena in chiral systems. Here, we investigate reflection properties on the surface of a medium ruled by axion electrodynamics, which effectively describes optical aspects of Weyl semimetals. We show that these chiral media can manifest anomalous reflectance (R greater than unity) for some frequency windows, depending on the signs of the two involved conductivities. Such a reflectance can increase with the frequency, being always greater than 1 in certain frequency bands. We also examine the complex Kerr angles at normal incidence on the chiral medium. Giant Kerr angle is observed within the absorption window, while the Kerr ellipticity may be used to determine the relative sign of the magnetic conductivity.
Other Condensed Matter (cond-mat.other), High Energy Physics - Theory (hep-th), Optics (physics.optics)
8 pages, 5 figures
Anomalous magnetoresistance in an antiferromagnetic Kagome semimetal heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Xionghua Liu, Qiyuan Feng, Weibin Cui, Hanjie Guo, Yubin Hou, Xiaomin Zhang, Yongcheng Deng, Dong Zhang, Jing Zhang, Qingyou Lu, Kaiyou Wang
Antiferromagnetic Kagome semimetals have attracted tremendous attentions for their potential application in antiferromagnetic topological spintronics. Effectively manipulating Kagome antiferromagnetic states could reveal abundant physical phenomena induced from quantum interactions between topology, spin, and correlation. Here, we achieved tunable spin textures of FeSn thin films via introducing interfacial Dzyaloshinskii Moriya interaction from heavy-metal Pt overlayer. With increasing FeSn thickness, the variable spin textures result in gradual change in Hall resistivity and magnetoresistance. Importantly, an unconventional damped oscillatory-like behavior of magnetoresistance at relatively low magnetic field can be observed in thin FeSn-Pt samples. This oscillatory like magnetoresistance feature was confirmed to be related to the special topological spin textures revealed by magnetic force microscopy measurements. The formation of rich variety of topological spin textures in association with exotic magneto-transport properties in antiferromagnetic Kagome FeSn heterostructures offers new perspectives for understanding the novel emergent phenomena in Kagome antiferromagnets.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 4 figures
Continuous sample space reducing stochastic process
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-25 20:00 EDT
Rahul Chhimpa, Avinash Chand Yadav</a>
We propose a simple model for sample space reducing (SSR) stochastic process, where the dynamical variable denoting the size of the state space is continuous. In general, one can view the model as a multiplicative stochastic process, with a constraint that the size of the state space cannot be smaller than a visibility parameter $ \epsilon$ . We study the survival time statistics that reveal a subtle difference from the discrete version of the process. A straightforward generalization can explain the noisy SSR process, characterized by a tunable parameter $ \lambda \in [0, 1]$ . We also examine the statistics of the size of the state space that follows a power-law distributed probability $ \mathbb{P}_{\epsilon}(z\le \epsilon) \sim z^{-\alpha}$ , with a nontrivial value of the exponent as a function of the tunable parameter $ \alpha = 1+\lambda$ .
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 6 figures
Topological Layer-Spin Filter in Screw Dislocation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Jiaojiao Zhou, Hong Hu, Jiangying Yu, Lin Xu, Shu-guang Cheng, Hua Jiang
While the quantum spin Hall effect leverages two-dimensional topological states to manipulate spin without dissipation, layertonics extends this paradigm to three dimension by enabling control over the layer degree of freedom. Topological materials incorporating screw dislocations exhibit the capability for simultaneous manipulation of both electronic spin and layer degrees of freedom. In this work, the electronic transport properties of a multilayer Kane-Mele model with screw dislocations is studied theoretically. Numerical simulations of a screw dislocation reveal that dissipationless quantum spin Hall edge states propagate not only at the outer boundaries of the structure but also along the screw dislocation itself, working as layer-spin filter. In detail, 1) the spin-up and spin-down carriers starting from the same source layer flow to different drain layers along the topological channels, respectively. 2) The spin of carriers flowing into a given drain layer is determined by the input source layer. Moreover, we found that the transmission coefficient and spin polarization remain robust against Anderson disorder. Under magnetic disorder, spin flip and backscattering occur, suppressing the transmission coefficient while maintaining nearly unchanged spin polarization. Finally, the layer- and spin-resolved transport properties in a device with two screw dislocations are investigated as well. We have developed an innovative methodology to modulate electron transport with simultaneous layer and spin resolution.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Accepted for publication in Phys. Rev. B. In production
Exploring the functional properties of diamond-like quaternary compound Li$_2$ZnGeS$_4$ for potential energy applications: A theoretical approach
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Celestine Lalengmawia, Michael T. Nunsanga, Saurav Suman, Zosiamliana Renthlei, Lalruat Sanga, Hani Laltlanmawii, Lalhriat Zuala, Shivraj Gurung, Amel Laref, Dibya Prakash Rai
It is anticipated that wide-bandgap semiconductors (WBGSs) would be useful materials for energy production and storage. A well-synthesized, yet, scarcely explored diamond-like quaternary semiconductor-Li$ _2$ ZnGeS$ _4$ has been considered for this work. Herein, we have employed two well-known functionals GGA and mGGA within a frame-work of density functional theory (DFT). We have explored the electronic, optical, mechanical, and piezo-electromechanical properties. Our results are in qualitative agreement with some of the previously reported data. The structural stabilities have been confirmed using the Born stability criteria and Molecular-dynamic (MD) simulations. Based on our findings, we claim that Li$ _2$ ZnGeS$ _4$ is the most probable candidate for optoelectronics and piezoelectric applications.
Materials Science (cond-mat.mtrl-sci)
Surface Material Dependence in Powder Triboelectric Charging
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-25 20:00 EDT
Tom F. O’Hara, Ellen Player, Graham Ackroyd, Peter J. Caine, Karen L. Aplin
Triboelectric charging of granular materials against container walls is a critical yet poorly understood phenomenon affecting many industrial powder handling processes. Charge accumulation can cause material flow disruptions, adhesion issues, and pose serious safety risks, such as providing ignition sources for dust cloud explosions. This study investigates particle-wall charging behaviour for materials with varying size, shape, and electrical resistivity. Aluminium surfaces are used as a reference case, followed by analysis of labradorite, an analogue for volcanic ash, to examine charging interactions with various wall materials. Finally, the triboelectric response of industrially relevant materials used in flexible intermediate bulk containers, including both lined and unlined variants, is assessed. Results show that stainless steel surfaces generate the least charge, while the presence of insulating polyethene liners increases charging significantly. These findings contribute to a deeper understanding of triboelectric charging mechanisms in powder transfer operations and inform safer industrial practice.
Soft Condensed Matter (cond-mat.soft)
Submitted conference paper for the IEEE Proceedings of the Electrostatics Society of America Joint Conference on Electrostatics 2025
Theory of Magnetization Temperature Dependence in Ferrimagnetics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Rostyslav O. Serha, Anna Pomyalov, Andrii V. Chumak, Victor S. L’vov
Recent advancements in spintronics and fundamental physical research have brought increased attention to the rare-earth-based magnetically ordered materials. One of the important properties of these materials is the temperature dependence of the spontaneous magnetization $ M(T)$ . Recently, a successful framework was proposed for the theoretical description of M(T) across the entire temperature range from zero to the Curie temperature in simple cubic ferromagnetics, EuO and EuS. We extend this approach to compute and analyze $ M(T)$ for multi-sublattice collinear ferrimagnetics such as Yttrium Iron Garnet $ Y_3Fe_5 O_{12}$ . We analyzed and generalized for multi-sublattice collinear ferrimagnetics two well-known approximations describing $ M(T)$ . The first approach is the Bloch-3/2 law, which describes the suppression of $ M(T)$ due to spin-wave excitation, and is valid in the low-temperature limit $ T << T_c$ . The second one is Weiss’s mean-field approximation, which provides a reasonable description of $ M(T)$ near $ T_c$ . Using a single tuning parameter, we combine these two approaches to describe $ M(T)$ for any $ 0<T<T_c$ . The theoretical result for $ M(T)$ aligns well with our measurements and the previously available experimental data across the entire temperature range. We also demonstrate that experimental and theoretical dependences $ M(T)$ follow the mean-field prediction $ \sqrt{T_c - T }$ for almost all temperatures.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
17 pages, 5 figures
Dissipation functions and Brownian oscillators
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-25 20:00 EDT
Matteo Colangeli, Lamberto Rondoni, Pasquale Vozza
We develop a general framework for response theory in diffusion processes governed by Fokker-Planck equations, based on the notion of the Dissipation Function. Using the analytically solvable Brownian oscillator model, we derive exact response formulae for both overdamped and underdamped dynamics of harmonically bound Brownian particles. We also demonstrate that for certain observables and under suitable time scaling, the operations of model reduction and response formula extraction commute.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
Relaxation Dynamics in Atomic-Molecular Bose Condensates in the Presence of Gaussian Noise
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-25 20:00 EDT
We investigate the dynamics of atomic and molecular bosons weakly coupled via Feshbach detuning in the presence of Gaussian white noise. The time-evolution of the population imbalance between the two species, as well as the coherence of the system are analyzed using a Bloch sphere model. We observe that the system exhibits relaxation of the Bloch vector components towards a stable equilibrium. In the population imbalance dynamics, the relaxation rates predicted by the Bogoliubov Born Green Kirkwood Yvon (BBGKY) hierarchy are found to be smaller than those calculated with a simple the mean field approximation. As for the coherence dynamics, the inclusion of correlations and fluctuations in the system can either increase or decrease the relaxation time, depending on the initial conditions. We attribute the increase in the relaxation time to the emergence of a structured noise, and the subsequent suppression of certain dephasing channels. We also study the impact of correlations and fluctuations on time-averaged quantities like the drift speed, the fringe visibility, the phase entanglement etc., and find the results to be in perfect agreement with the properties of the relaxation dynamics.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
13 pages, 12 figures
Dynamics of Quantum Droplets in a Quasi-one-dimensional Framework: An Analytical Approach
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-25 20:00 EDT
Quantum droplets have been recently observed in dipolar Bose-Einstein condensates (BECs) and in BEC mixtures. This forms the motivation for us to explore the dynamics of these droplets. We make use of the Extended Gross-Pitaevski equation which apart from the effective mean field (MF) interaction, also includes a beyond mean field interaction. The competition of these two interactions in the context of droplet formation is explored. Further, the conditions for droplet formation are studied.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
7 pages, 4 figures; To appear in Eur. Phys. J. D
Dis-GEN: Disordered crystal structure generation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Martin Hoffmann Petersen, Ruiming Zhu, Haiwen Dai, Savyasanchi Aggarwal, Nong Wei, Andy Paul Chen, Arghya Bhowmik, Juan Maria Garcia Lastra, Kedar Hippalgaonkar
A wide range of synthesized crystalline inorganic materials exhibit compositional disorder, where multiple atomic species partially occupy the same crystallographic site. As a result, the physical and chemical properties of such materials are dependent on how the atomic species are distributed among the corresponding symmetrical sites, making them exceptionally challenging to model using computational methods. For this reason, existing generative models cannot handle the complexities of disordered inorganic crystals. To address this gap, we introduce Dis-GEN, a generative model based on an empirical equivariant representation, derived from theoretical crystallography methodology. Dis-GEN is capable of generating symmetry-consistent structures that accommodate both compositional disorder and vacancies. The model is uniquely trained on experimental structures from the Inorganic Crystal Structure Database (ICSD) - the world’s largest database of identified inorganic crystal structures. We demonstrate that Dis-GEN can effectively generate disordered inorganic materials while preserving crystallographic symmetry throughout the generation process. This approach provides a critical check point for the systematic exploration and discovery of disordered functional materials, expanding the scope of generative modeling in materials science.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
Unconventional Thermalization of a Localized Chain Interacting with an Ergodic Bath
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-25 20:00 EDT
Konrad Pawlik, Nicolas Laflorencie, Jakub Zakrzewski
The study of many-body localized (MBL) phases intrinsically links spectral properties with eigenstate characteristics: localized systems exhibit Poisson level statistics and area-law entanglement entropy, while ergodic systems display volume-law entanglement and follow random matrix theory predictions, including level repulsion. Here, we introduce the interacting Anderson Quantum Sun model, which significantly deviates from these conventional expectations. In addition to standard localized and ergodic phases, we identify a regime that exhibits volume-law entanglement coexisting with intermediate spectral statistics. We also identify another nonstandard regime marked by Poisson level statistics, sub-volume entanglement growth, and rare-event-dominated correlations, indicative of emerging ergodic instabilities. These results highlight unconventional routes of ergodicity breaking and offer fresh perspectives on how Anderson localization may be destabilized.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
about 5pp+2(endmatter)+4(suppl) or this http URL MOST WELCOME
Static and dynamic properties of a binary, symmetric mixture of ultrasoft particles in the vicinity of criticality
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-25 20:00 EDT
Tanmay Biswas, Gerhard Kahl, Gaurav P. Shrivastav
We investigate the static and the dynamic properties of an binary, equimolar, size-symmetric mixture of ultrasoft particles in the vicinity of the critical point of the system. Based on the generalized exponential potential (GEM) of order four for the particle interaction and using extensive molecular dynamics simulations in the canonical ensemble we investigate the above mentioned properties for various scenarios: we consider several super- and subcritical states, we expose the system to rapid quenches and to external shearing forces. Based on an accurate determination of the phase diagram and of the location of the critical point we study the static structure of the system in terms of particle-based radial distribution functions. As systems of GEM particles are prone to cluster formation we complement these investigations by a detailed analysis of the composition of the clusters and of their spatial correlations for the different scenarios introduced above. Furthermore we analyse the temperature dependence of the diffusivity of the particles and of the shear viscosity of the system. All these data provide a detailed and profound insight into the properties of the system under phase separation conditions and near criticality.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Observation of Kibble-Zurek Behavior across Topological Transitions of a Chern Band in Ultracold Atoms
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-07-25 20:00 EDT
Huan Yuan, Chang-Rui Yi, Jia-Yu Guo, Xiang-Can Cheng, Rui-Heng Jiao, Jinyi Zhang, Shuai Chen, Jian-Wei Pan
The Kibble-Zurek (KZ) mechanism renders a theoretical framework for elucidating the formation of topological defects across continuous phase transitions. Nevertheless, it is not immediately clear whether the KZ mechanism applies to topological phase transitions. The direct experimental study for such a topic is hindered by quenching a certain parameter over orders of magnitude in topological materials. Instead, we investigate the KZ behavior across topological transitions of a Chern band in two-dimensional (2D) optical Raman lattices with quantum gases. Defined as the defects, excitation density is reconstructed via measuring the spin wave functions, with which the power-law scaling of total excitation density is extracted and such scaling could be interpreted within the KZ framework. Our work has heralded the commencement of experimentally exploring the KZ mechanism of the topological phase transitions.
Quantum Gases (cond-mat.quant-gas)
Nucleation of magnetic textures in stripe domain bifurcations for reconfigurable domain wall racetracks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
V.V. Fernández, S. Ferrer, A. Hierro-Rodríguez, M. Vélez
Within the racetrack memory paradigm, systems exploiting magnetic guiding potentials instead of geometrical ones, allow for enhancing the versatility of the final devices adding magnetic reconfigurable capabilities. Hard/soft magnetic multilayers with stripe domain configurations fulfill these requirements. In these systems, the topology of the generated textures that would act as information carriers, is strongly conditioned by the stripe lattice configuration. Micromagnetic simulations have been used to study the magnetization reversal process in NdCo$ _5$ /Py reconfigurable racetracks. By using skyrmionic charges and magnetic vorticity lines, the topological transformations controlling the nucleation of vortices, antivortices, Bloch lines and Bloch points has been analyzed. It has been shown that magnetic topological charge exchanges between textures rule the formation of vortex/antivortex pairs with opposite polarities, key for the guided propagation through the stripe pattern.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Dislocation-Driven Nucleation Type Switching Across Repeated Ultrafast Magnetostructural Phase Transition
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Jan Hajduček, Antoine Andrieux, Jon Ander Arregi, Martin Tichý, Paolo Cattaneo, Beatrice Ferrari, Fabrizio Carbone, Vojtěch Uhlíř, Thomas LaGrange
Controlling magnetic order on ultrafast timescales, driven by spintronic and recording applications, is one of the main directions of current research in magnetism. Despite major advances in understanding the temporal evolution of magnetic order upon its emergence or quenching, experimental demonstration of the local link between microstructure and dynamic nucleation is missing. Here, taking advantage of the high structural and magnetic resolution of in situ transmission electron microscopy, we observe that cumulative laser irradiation significantly alters the nucleation pathway of the first-order antiferromagnetic to ferromagnetic phase transition of FeRh thin films, causing the transition to switch from homogeneous to heterogeneous nucleation. This leads to a decrease of 20 K in transition temperature and the emergence of sub-micron magnetic vortices as preferential nucleation motifs. These vortices are pinned in the film by underlying dislocation networks. We observe that the dislocation networks are formed and rearranged upon repeated crossing of the phase transition using femtosecond and picosecond laser pulses. Our results establish a direct link between defect formation, nucleation energetics, and the microscopic morphology of the nucleated ferromagnetic phase, with broad implications for ultrafast stroboscopic experiments and defect-mediated phase transitions in functional materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Preprint
Persistent paramagnons in high-temperature infinite-layer nickelate superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-07-25 20:00 EDT
Yujie Yan, Ying Chan, Xunyang Hong, S. Lin Er Chow, Zhaoyang Luo, Yuehong Li, Tianren Wang, Yuetong Wu, Izabela Biało, Nurul Fitriyah, Saurav Prakash, Xing Gao, King Yau Yip, Qiang Gao, Xiaolin Ren, Jaewon Choi, Ganesha Channagowdra, Jun Okamoto, Xingjiang Zhou, Zhihai Zhu, Liang Si, Mirian Garcia-Fernandez, Ke-Jin Zhou, Hsiao-Yu Huang, Di-Jing Huang, Johan Chang, A. Ariando, Qisi Wang
The recent discovery of high-temperature superconductivity in hole-doped SmNiO$ _2$ , exhibiting the record-high transition temperature $ T_c$ among infinite-layer (IL) nickelates, has opened a new avenue for exploring design principles of superconductivity. Experimentally determining the electronic structure and magnetic interactions in this new system is crucial to elucidating the mechanism behind the enhanced superconductivity. Here, we report a Ni $ L$ -edge resonant inelastic x-ray scattering (RIXS) study of superconducting Sm-based IL nickelate thin films Sm$ _{1-x-y-z}$ Eu$ _x$ Ca$ _y$ Sr$ _z$ NiO$ _2$ (SECS). Dispersive paramagnonic excitations are observed in both optimally and overdoped SECS samples, supporting a spin-fluctuation-mediated pairing scenario. However, despite the two-fold enhancement of $ T_c$ in the Sm-based nickelates compared to their Pr-based counterparts, the effective exchange coupling strength is reduced by approximately $ 20%$ . This behavior contrasts with hole-doped cuprates, where magnetic interactions correlate positively with $ T_c$ , highlighting essential differences in their superconducting mechanisms.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Supplementary Information available upon request
How Soft is Too Soft? Tuning Order and Disorder in Dimeric Core-Soft Colloids with Bond Flexibility
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-25 20:00 EDT
Leandro B. Krott, Davi Felipe Kray Silva, A. de J. Ríos-Roldan, Victor M. Trejos, J. Antonio Moreno-Razo, José Rafael Bordin
We employ molecular dynamics simulations to explore how internal flexibility affects phase transitions in soft-matter systems composed of dimers interacting via a core-softened potential with two characteristic length scales. Monomers are connected by harmonic springs with varying stiffness, allowing us to tune the dimer rigidity from highly flexible to nearly rigid. Flexible dimers reproduce the behavior of monomeric systems, displaying well-defined BCC and HCP crystalline phases separated by a narrow amorphous region. As the bond stiffness increases, this amorphous phase gives way to a coexistence region between BCC and HCP structures. In the rigid limit, amorphous regions reemerge and expand, and high-density systems fail to crystallize completely, instead forming mixed phases with HCP-like and disordered local environments. This transition arises from geometric frustration: rigid dimers are unable to adjust their internal configuration to optimize local packing, thereby suppressing crystallization and promoting amorphization. Our findings reveal that bond flexibility is a key control parameter governing structural organization in core-softened colloidal and molecular systems, offering insights for the design of tunable soft materials.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
Oscillator Potts machines: An overdamped Langevin model for low-energy sampling of the standard Potts model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-25 20:00 EDT
The standard Potts model is a fundamental model in statistical physics that generalizes the Ising model. Although Ising machines, as Langevin models, have been widely studied for sampling the Ising model, studies of Langevin models for sampling the standard Potts model are still lacking. In this work, we present a compact and physically realizable Langevin model that serves as a sampler for sampling the low-energy spin configurations of the standard Potts model.
Statistical Mechanics (cond-mat.stat-mech), Applied Physics (physics.app-ph)
Antiferromagnetic Hall-Memristors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Gaspar De la Barrera, Alvaro S. Nunez
Spin-memristors are a class of materials that can store memories through the control of spins, potentially leading to novel technologies that address the constraints of standard silicon electronics, thereby facilitating the advancement of more intelligent and energy-efficient computing systems. In this work, we present a spin-memristor based on antiferromagnetic materials that exhibit Hall-memresistance. Moreover, the nonlinear Edelstein effect acts as both a writer and eraser of memory registers. We provide a generic symmetry-based analysis that supports the viability of the effect. To achieve a concrete realization of these ideas, we focus on CuMnAs, which has been shown to have a controllable nonlinear Hall effect. Our results extend the two-terminal spin-memristor setting, which is customarily the standard type of device in this context, to a four-terminal device.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 5 figures
Quasicrystalline Altermagnetism
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Rui Chen, Bin Zhou, Dong-Hui Xu
Altermagnets are a recently discovered class of magnetic materials that combine a collinear, zero-magnetization spin structure, characteristic of antiferromagnets, with spin-split electronic bands, a hallmark of ferromagnets. This unique behavior arises from the breaking of combined time-reversal and spatial symmetries (such as inversion or lattice translation), which are preserved in conventional antiferromagnets. To date, research has focused on altermagnetic phases in periodic crystals, where the order is linked to specific crystallographic rotation symmetries. In this work, we demonstrate that quasicrystals, which possess rotational symmetries forbidden in periodic lattices, can host exotic altermagnetic orders. Using symmetry analysis and self-consistent mean-field theory, we predict stable $ g$ -wave and $ i$ -wave altermagnetism in octagonal and dodecagonal quasicrystals, respectively. These novel phases are characterized by global $ C_8T$ and $ C_{12}T$ symmetries and manifest as unique anisotropic spin-splittings in their spectral functions and spin conductance, featuring characteristic eight- and twelve-fold nodal structures that serve as unambiguous experimental fingerprints. Our findings establish quasicrystals as a versatile platform for realizing unconventional altermagnetic orders beyond the constraints of crystallographic symmetry.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Efficient $GW$ band structure calculations using Gaussian basis functions and application to atomically thin transition-metal dichalcogenides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Rémi Pasquier, María Camarasa-Gómez, Anna-Sophia Hehn, Daniel Hernangómez-Pérez, Jan Wilhelm
We present a $ GW$ space-time algorithm for periodic systems in a Gaussian basis including spin-orbit coupling. We employ lattice summation to compute the irreducible density response and the self-energy, while we employ $ k$ -point sampling for computing the screened Coulomb interaction. Our algorithm enables accurate and computationally efficient quasiparticle band structure calculations for atomically thin transition-metal dichalcogenides. For monolayer MoS$ _\text{2}$ , MoSe$ _\text{2}$ , WS$ _\text{2}$ , and WSe$ _\text{2}$ , computed $ GW$ band gaps agree on average within 50~meV with plane-wave-based reference calculations. $ G_0W_0$ band structures are obtained in less than two days on a laptop (Intel i5, 192 GB RAM) or in less than 30 minutes using 1024 cores. Overall, our work provides an efficient and scalable framework for $ GW$ calculations on atomically thin materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph)
25 pages, 10 figures
Quantum Griffiths phase in the kagome Kondo lattice CeRh${0.9}$Pd${0.1}$Sn
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
Nan Tang, Rajesh Tripathi, Yasuyuki Shimura, Toshiro Takabatake, Devashibhai A. Adroja, Philipp Gegenwart
CeRhSn is a valence fluctuating heavy-fermion metal with a twisted Ce-kagome lattice, displaying zero-field quantum criticality, previously associated with geometrical frustration. The partial substitution of Rh by Pd in CeRh$ _{1-x}$ Pd$ _x$ Sn enlarges the unit-cell volume, suppresses valence fluctuations, decreases the Kondo temperature and stabilizes a possible long-range antiferromagnetic (AFM) ordered ground state with $ T_N=0.8$ K at $ x=0.5$ . Previous thermodynamic and spectroscopic measurements for $ x=0.1$ suggested a quantum critical spin liquid. We report low-temperature dilatometry and magnetization measurements on CeRh$ _{0.9}$ Pd$ _{0.1}$ Sn and compare with published low-$ T$ specific heat data. The absence of a Grüneisen parameter divergence excludes a conventional quantum criticality scenario. Instead, the weak power-law divergences signal non-Fermi liquid (NFL) behavior, according to a disorder-driven quantum Griffiths phase scenario. At low temperatures, a negative thermal expansion is found in fields above approximately 0.5 T and the NFL scaling breaks down, probably due to the polarization of AFM correlations.
Strongly Correlated Electrons (cond-mat.str-el)
2D ferroelectricity accompanying antiferro-orbital order in semi-metallic WTe$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Fangyuan Gu, Ruoshi Jiang, Wei Ku
The first switchable electric polarization in metals was recently discovered in bilayer and trilayer WTe2. Strangely, despite the tininess of the ordered polarization, the ferroelectricity survives up to 350 K, rendering the mechanism of such ferroelectricity challenging for standard understandings. Here, via a density-functional-based multi-energy-scale analysis of the system’s broken symmetries, we identify a weak out-of-plane ferroelectricity accompanying a strong in-plane antiferro-orbital order. This unusual low-energy correlation, which emerges from an antiferroelectric structure formed at much higher energy, naturally explains the above puzzling observation. This result reveals an unprecedented paradigm of electronic ferroelectricity generally applicable to 2D polar metals with ultrafast-switchable polarization ideal for the next-generation non-volatile memory and other devices.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Local Hall Conductivity in Disordered Topological Insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Zachariah Addison, Nandini Trivedi
We derive the expression for the local Hall conductivity for systems that lack translation symmetry and use it to study the local fluctuations of the Hall signal around disordered patches in magnetic insulators. We find that the regime in parameter space over which the system is a Chern insulating state increases upon inclusion of non-magnetic potential disorder. In addition, the phase space over which the topological Anderson insulator exists can be enhanced by breaking up a single disordered patch into multiple smaller patches with the same total amount of disorder. We expect our results will motivate the next generation of local scanning and local impedance spectroscopy experiments to visualize Hall currents around patches in the bulk of a disordered topological insulator.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn)
12 pages, 8 figures
Emergent-gravity Hall effect from quantum geometry
New Submission | Other Condensed Matter (cond-mat.other) | 2025-07-25 20:00 EDT
Hiroki Yoshida, Takehito Yokoyama
We theoretically propose a Hall effect driven by effective gravitational fields arising from quantum geometry. We develop four mechanisms for this ‘’emergent-gravity Hall effect” : real-space gravity, momentum-space gravity, gravitional anomalous velocity, and gravitational Lorentz force which are described by the Christoffel symbols in real, momentum, and time spaces. We construct a unified theoretical framework to systematically investigate the effects of emergent gravity in these spaces on transport phenomena based on the semiclassical theory. We demonstrate these effects by model calculations and clarify the conditions under which a finite Hall response can arise. Our findings open a new avenue for exploring gravitational effects in quantum systems.
Other Condensed Matter (cond-mat.other), General Relativity and Quantum Cosmology (gr-qc), Quantum Physics (quant-ph)
5 pages, 3 figures
A note on the dynamics of extended-context disordered kinetic spin models
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-07-25 20:00 EDT
Jacob A. Zavatone-Veth, Cengiz Pehlevan
Inspired by striking advances in language modeling, there has recently been much interest in developing autogressive sequence models that are amenable to analytical study. In this short note, we consider extensions of simple disordered kinetic glass models from statistical physics. These models have tunable correlations, are easy to sample, and can be solved exactly when the state space dimension is large. In particular, we give an expository derivation of the dynamical mean field theories that describe their asymptotic statistics. We therefore propose that they constitute an interesting set of toy models for autoregressive sequence generation, in which one might study learning dynamics.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Semi-expository note; 29 pages, 5 figures
Active Δ-learning with universal potentials for global structure optimization
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Joe Pitfield, Mads-Peter Verner Christiansen, Bjørk Hammer
Universal machine learning interatomic potentials (uMLIPs) have recently been formulated and shown to generalize well. When applied out-of-sample, further data collection for improvement of the uMLIPs may, however, be required. In this work we demonstrate that, whenever the envisaged use of the MLIPs is global optimization, the data acquisition can follow an active learning scheme in which a gradually updated uMLIP directs the finding of new structures, which are subsequently evaluated at the density functional theory (DFT) level. In the scheme, we augment foundation models using a {\Delta}-model based on this new data using local SOAP-descriptors, Gaussian kernels, and a sparse Gaussian Process Regression model. We compare the efficacy of the approach with different global optimization algorithms, Random Structure Search, Basin Hopping, a Bayesian approach with competitive candidates (GOFEE), and a replica exchange formulation (REX). We further compare several foundation models, CHGNet, MACE-MP0, and MACE-MPA. The test systems are silver-sulfur clusters and sulfur-induced surface reconstructions on Ag(111) and Ag(100). Judged by the fidelity of identifying global minima, active learning with GPR-based {\Delta}-models appears to be a robust approach. Judged by the total CPU time spent, the REX approach stands out as being the most efficient.
Materials Science (cond-mat.mtrl-sci)
Modulation of Non-equilibrium Structures of Active Dipolar Particles by an External Field
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-07-25 20:00 EDT
Baptiste Parage, Sara Jabbari-Farouji
We study the impact of an external alignment field on the structure formation and polarization behavior of low-density dipolar active particles in three dimensions. Performing extensive Brownian dynamics simulations, we characterize the interplay between long-range dipolar interactions, field alignment, and self-propulsion. We find that the competition between activity (favoring bond breaking) and the field’s orientational constraint (promoting bond formation) gives rise to a rich variety of self-assembled, actuated structures. At low to intermediate field strengths, disordered fluids composed of active chains and active percolated networks can emerge, whereas strong fields drive the formation of polarized columnar clusters. Counterintuitively, low activity levels significantly extend the range of field strengths over which percolated networks persist. This structural evolution manifests in the polarization response of strongly dipolar systems, which exhibit a transition from super-Langevin to sub-Langevin behavior with increasing activity, as a result of the coupling between structure formation and activity-induced bond breaking.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Deep learning-enabled large-scale analysis of particle geometry-lithiation correlations in battery cathode materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
Binbin Lin, Luis J.Carrillo, Xiang-Long Peng, Wan-Xin Chen, David A.Santosb, Sarbajit Banerjeeb, Bai-Xiang Xu
A deep learning model is employed to address the challenging problem of V2O5 nanoparticle segmentation and the correlation between the chemical composition and the geometrical features of lithiated V2O5 nanoparticles as an exemplar of a phase-transforming battery cathode material. First, the deep learning-enabled segmentation model is integrated with the singular value decomposition technique and a spectral database to generate accurate composition and phase maps capturing lithiation heterogeneities as imaged using scanning transmission X-ray microscopy. These phase maps act as the output properties for correlation analysis. Subsequently, the quantitative influences of the geometrical features of nanoparticles such as the particle size (i.e., projected perimeter and area), the aspect ratio, circularity, convexity, and orientation on the lithiation phase maps are revealed. These findings inform strategies to improve lithiation uniformity and reduce stress in phase-transforming lithium battery materials via optimized particle geometry.
Materials Science (cond-mat.mtrl-sci)
Deep Variational Free Energy Calculation of Hydrogen Hugoniot
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
Zihang Li, Hao Xie, Xinyang Dong, Lei Wang
We develop a deep variational free energy framework to compute the equation of state of hydrogen in the warm dense matter region. This method parameterizes the variational density matrix of hydrogen nuclei and electrons at finite temperature using three deep generative models: a normalizing flow model that represents the Boltzmann distribution of the classical nuclei, an autoregressive transformer that models the distribution of electrons in excited states, and a permutational equivariant flow model that constructs backflow coordinates for electrons in Hartree-Fock orbitals. By jointly optimizing the three neural networks to minimize the variational free energy, we obtain the equation of state and related thermodynamic properties of dense hydrogen. We compare our results with other theoretical and experimental results on the deuterium Hugoniot curve, aiming to resolve existing discrepancies. The calculated results provide a valuable benchmark for deuterium in the warm dense matter region.
Strongly Correlated Electrons (cond-mat.str-el), Machine Learning (cs.LG), Computational Physics (physics.comp-ph)
7+17 pages, 5+14 figures, for source code and raw data, see this https URL
Symmetry driven spin anisotropic magnetotransport in quantum spin Hall insulator WTe2 1T
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Shrushti Tapar, Bent Weber, Saroj P Dash, 3 Shantanu Mukherjee, Bhaskaran Muralidharan
We present a comprehensive magnetotransport analysis of monolayer 1T WTe2, highlighting the role of nonsymmorphic symmetries in governing edge-state spin behavior. By comparing the electronic transmission in nanoribbons with edges along the crystallographic y and x directions, our analysis reveals a pronounced anisotropy in the magnetic field response. The y-edge ribbon exhibits significant spin splitting of edge-state bands in both energy and momentum space, along with a strong angular dependence of the conductance. The observed magnetotransport response indicates a spin quantization axis that aligns with the out-of-plane spin quantization axis reported in previous experimental studies. In contrast, the x edge ribbon shows negligible spin splitting under magnetic fields, which is attributed to nonsymmorphic symmetries such as glide mirror and screw rotation, that protects degeneracies along the Gamma X direction, even when time-reversal symmetry is broken. The energy-resolved current density and angular transmission analyses confirm that this anisotropy originates from edge states, while bulk states remain largely insensitive to the field orientation. Our results establish direct transport-spectroscopy based evidence of nonsymmorphic-symmetry-protected spin degeneracy in the 1T WTe2, and underscores its promise for spintronic devices that leverage symmetry-protected and directionally selective transport channels.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 7 Figures
Large deviations of ionic currents in dilute electrolytes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-07-25 20:00 EDT
Jafar Farhadi, David T. Limmer
We evaluate the exponentially rare fluctuations of the ionic current for a dilute electrolyte by means of macroscopic fluctuation theory. We consider the fluctuating hydrodynamics of a fluid electrolyte described by a stochastic Poisson-Nernst-Planck equation. We derive the Euler-Lagrange equations that dictate the optimal concentration profiles of ions conditioned on exhibiting a given current, whose form determines the likelihood of that current in the long-time limit. For a symmetric electrolyte under small applied voltages, number density fluctuations are small, and ionic current fluctuations are Gaussian with a variance determined by the Nernst-Einstein conductivity. Under large applied potentials, where number densities vary, the ionic current distribution is generically non-Gaussian. Its structure is constrained thermodynamically by Gallavotti-Cohen symmetry and the thermodynamic uncertainty principle.
Statistical Mechanics (cond-mat.stat-mech), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph)
9 pages, 6 figures, comments welcome
Ultrafast coherent magnon spin currents in antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Torstein Hegstad, Johan H. Mentink
Generating coherent magnon spin currents with the highest frequencies and shortest wavelengths is a key challenge in ultrafast spintronics and magnonics. A promising route is to excite counter-propagating magnon pairs. In antiferromagnets, such pairs can be accessed in the ultrafast regime, where coherent dynamics are dominated by magnons at the edge of the Brillouin zone. However, it has seemed impossible to generate a net spin current from coherent magnon pairs. Here we show that a coherent superposition of multiple magnon-pair modes can produce such a current in parity-time symmetric antiferromagnets. The ultrafast coherent spin currents are excited with linearly polarized light, with the light polarization steering the current direction. Finally, by superposing two orthogonal spin currents, circular spin currents can be generated, which have not been discussed for steady-state currents.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
9 pages, 6 figures
Variational Monte Carlo Optimization of Topological Chiral Superconductors
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
Minho Luke Kim, Abigail Timmel, Xiao-Gang Wen
We perform the variational Monte Carlo calculation for recently proposed chiral superconducting states driven by strong Coulomb interactions. We compare the resulting energetics of these electronic phases for the electron dispersion relation $ E_k = c_2 k^2+c_4 k^4$ . Motivated by the recent discovery of chiral superconductivity in rhombohedral graphene systems, we apply our analysis to relevant parameter regimes. We demonstrate that topological chiral superconducting phases (including a spin-unpolarized state) can be energetically favored over the spin-valley polarized Fermi liquid above the density of Wigner crystal phase. Our results show that the preference for chiral superconductivity is strongest when $ c_2$ lies between zero and a negative value, corresponding to a system on the verge of forming a hole pocket around $ k=0$ . This finding suggests that superconductivity can arise from pure repulsive Coulomb interactions in systems with an almost flat band bottom, without relying on the pairing instability of a Fermi surface. This mechanism opens a new pathway to superconductivity beyond the conventional BCS mechanism.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
14 pages, 9 figures
Programmable phase selection between altermagnetic and non-centrosymmetric polymorphs of MnTe on InP via molecular beam epitaxy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-07-25 20:00 EDT
An-Hsi Chen, Parul R. Raghuvanshi, Jacob Cook, Michael Chilcote, Jason Lapano, Alessandro R. Mazza, Qiangsheng Lu, Sangsoo Kim, Yueh-Chun Wu, T. Zac Ward, Benjamin Lawrie, Guang Bian, James Burns, Jonathan D. Poplawsky, Myung-Geun Han, Yimei Zhu, Lucas Lindsay, Hu Miao, Robert G. Moore, Gyula Eres, Valentino R. Cooper, Matthew Brahlek
Phase selecting nearly degenerate crystalline polymorphs during epitaxial growth can be challenging yet is critical to targeting physical properties for specific applications. Here, we establish how phase selectivity of altermagnetic and non-centrosymmetric polymorphs of MnTe with high structural quality and phase purity can be programmed by subtle changes to the surface of lattice-matched InP substrates in molecular beam epitaxial (MBE) growth. Bulk altermagnetic MnTe is thermodynamically stable in the hexagonal NiAs-structure and is synthesized here on the (111)A surface (In-terminated) of InP, while the non-centrosymmetric, cubic ZnS-structure with wide band gap (> 3eV) is stabilized on the (111)B surface (P-terminated). Here we use electron microscopy, photoemission spectroscopy, and reflection high-energy electron diffraction, which together indicate that the phase selection is triggered at the interface and proceeds along the growing surface. First principles calculations suggest that interfacial termination and strain have a significant effect on the interfacial energy; stabilizing the NiAs polymorph on the In-terminated surface and the ZnS structure on the P-terminated surface. Selectively grown, high-quality films of MnTe polymorphs are key platforms that will enable our understanding of the novel properties of these materials, thereby facilitating their use in new applications ranging from spintronics to microelectronic devices.
Materials Science (cond-mat.mtrl-sci)
Superconductivity from dual-surface carriers in rhombohedral graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-07-25 20:00 EDT
Manish Kumar, Derek Waleffe, Anna Okounkova, Raveel Tejani, Vo Tien Phong, Kenji Watanabe, Takashi Taniguchi, Cyprian Lewandowski, Joshua Folk, Matthew Yankowitz
Intrinsic rhombohedral graphene hosts an unusual low-energy electronic wavefunction, predominantly localized at its outer crystal faces with negligible presence in the bulk. Increasing the number of graphene layers amplifies the density of states near charge neutrality, greatly enhancing the susceptibility to symmetry-breaking phases. Here, we report superconductivity in rhombohedral graphene arising from an unusual charge-delocalized semimetallic normal state, characterized by coexisting valence- and conduction-band Fermi pockets split to opposite crystal surfaces. In octalayer graphene, the superconductivity appears in five apparently distinct pockets for each sign of an external electric displacement field ($ D$ ). In a moiré superlattice sample where heptalayer graphene is aligned on one side to hexagonal boron nitride, two pockets of superconductivity emerge from a single sharp resistive feature. At higher $ D$ the same resistive feature additionally induces an $ h/e^{2}$ -quantized anomalous Hall state at dopings near one electron per moiré unit cell. Our findings reveal a novel superconducting regime in multilayer graphene and create opportunities for coupling to nearby topological states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Topological constraint on crystalline current
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-07-25 20:00 EDT
Tomohiro Soejima, Junkai Dong, Ophelia Evelyn Sommer, Daniel E. Parker, Ashvin Vishwanath
How much current does a sliding electron crystal carry? The answer to this simple question has important implications for the dynamic properties of the crystal, such as the frequency of its cyclotron motion, and its phonon spectrum. In this work we introduce a precise definition of a sliding crystal and compute the corresponding current $ \mathbf{j}_c$ for topological electron crystals in the presence of magnetic field. Our result is fully non-perturbative, does not rely on Galilean invariance, and applies equally to Wigner crystals and (anomalous) Hall crystals. In terms of the electron density $ \rho$ and magnetic flux density $ \phi$ , we find that $ \mathbf{j}_c = e(\rho-C\phi)\mathbf{v}$ . Surprisingly, the current receives a contribution from the many-body Chern number $ C$ of the crystal. When $ \rho = C\phi$ , sliding crystals therefore carry zero current. The crystalline current fixes the Lorentz force felt by the sliding crystal and the dispersion of low-energy phonons of such crystals. This gives us a simple counting rule for the number of gapless phonons: if a sliding crystal carries nonzero current in a magnetic field, there is a single gapless mode, while otherwise there are two gapless modes. This result can also be understood from anomaly-matching of emanant discrete translation symmetries – an idea that is also applicable to the dispersion of skyrmion crystals. Our results lead to novel experimental implications and invite further conceptual developments for electron crystals.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 + 8 pages, 1 figure