CMP Journal 2025-08-26
Statistics
Nature: 1
Nature Physics: 3
Nature Reviews Materials: 1
Physical Review Letters: 10
Physical Review X: 2
Review of Modern Physics: 2
arXiv: 102
Nature
Scalable total synthesis of saxitoxin and related natural products
Original Paper | Natural product synthesis | 2025-08-25 20:00 EDT
Yinliang Guo, Yiheng Li, Sihan Chen, Yige Wu, Oscar Poll, Zhouyang Ren, Zhonglin Liu, Roman Vlkolinsky, Michal Bajo, Christopher K. Prier, Kai-Jiong Xiao, Benjamin F. Cravatt, Marisa Roberto, Phil S. Baran
Saxitoxin (STX, 1), a potent neurotoxin from shellfish, first isolated in 19571, offers immense pharmaceutical potential due to its interaction with voltage-gated sodium channels2, that are ubiquitously present in all excitable cells of the central and periphperal nervous system3. Hundreds of synthetic studies towards this end have been disclosed thus far, yet, a fully modular and scalable approach to the family remains elusive4-12. Thus, here we show how a tactical combination of radical retrosynthesis, biocatalysis, and C-H functionalization logic can be combined to solve this problem resulting in a scalable approach to the STX family in less than 10 steps including the first total synthesis of neosaxitoxin (neoSTX, 4), a hydroxylated naturally occurring STX analog previously under clinical investigation13. The modular nature of the synthesis enables access to diverse analogs, that were previously inaccessible, and now have been evaluated through electrophysiological assays for biological activity.
Natural product synthesis
Nature Physics
Tubulin isotypes of C. elegans harness the mechanosensitivity of the lattice for microtubule luminal accessibility
Original Paper | Deformation dynamics | 2025-08-25 20:00 EDT
Yucheng Ye, Zheng Hao, Jingyi Luo, Wai Hei Lam, Zheng Liu, Xiang David Li, Yuanliang Zhai, Yuan Lin, Shih-Chieh Ti
Microtubules are hollow cylindrical cytoskeletal polymers of laterally associated protofilaments that contain head-to-tail aligned ɑ/β-tubulin heterodimers. Although the exposed microtubule exterior is readily accessible to proteins, the mechanism governing the accessibility of the confined microtubule lumen to luminal particles remains unknown. Here we show that certain tubulin family proteins (isotypes) facilitate luminal accessibility because of the mechanical properties and lateral interactions that they confer to the microtubules. We characterized the microtubules reconstituted from defined compositions of Caenorhabditis elegans tubulin isotypes. These tubulin isotypes form microtubules with comparable protofilament numbers but different luminal accessibility. We further revealed the role of tubulin isotypes in regulating the strength of inter-protofilament lateral interactions, which determines luminal accessibility through the mechanosensitivity of reversible protofilament separation. Deformation of the microtubule lattice, which generates stresses exceeding the strength of the lateral interactions, creates gaps between adjacent protofilaments, enhancing the accessibility of the lumen. Together, our findings uncovered the tubulin isotype-dependent mechanical plasticity that confers force sensitivity to the microtubule lattice and modulates the energy barrier for luminal proteins to access the lumen.
Deformation dynamics, Mechanical properties, Polymers, Single-molecule biophysics
Realization of an untrusted intermediate relay architecture using a quantum dot single-photon source
Original Paper | Quantum information | 2025-08-25 20:00 EDT
Mi Zou, Yu-Ming He, Yizhi Huang, Jun-Yi Zhao, Bin-Chen Li, Yong-Peng Guo, Xing Ding, Mo-Chi Xu, Run-Ze Liu, Geng-Yan Zou, Zhen Ning, Xiang You, Hui Wang, Wen-Xin Pan, Hao-Tao Zhu, Ming-Yang Zheng, Xiu-Ping Xie, Dandan Qin, Xiao Jiang, Yong-Heng Huo, Qiang Zhang, Chao-Yang Lu, Xiongfeng Ma, Teng-Yun Chen, Jian-Wei Pan
To fully exploit the potential of quantum technologies, quantum networks are needed to link different systems, enhancing applications in computing, cryptography and metrology. Central to these networks are quantum relays that can facilitate long-distance entanglement distribution and quantum communication. In this work, we present a modular and scalable quantum relay architecture using a high-quality single-photon source. The proposed network incorporates three untrusted intermediate nodes and is capable of a repetition rate of 304.52 MHz. We use a measurement-device-independent protocol to demonstrate secure key establishment over fibres covering up to 300 km. This study highlights the potential of single-photon sources in quantum relays to enhance information transmission, expand network coverage and improve deployment flexibility, with promising applications in future quantum networks.
Quantum information, Single photons and quantum effects
Enhancing nanoscale charged colloid crystallization near a metastable liquid binodal
Original Paper | Characterization and analytical techniques | 2025-08-25 20:00 EDT
Christian P. N. Tanner, Vivian R. K. Wall, Joshua Portner, Ahhyun Jeong, Avishek Das, James K. Utterback, Leo M. Hamerlynck, Jonathan G. Raybin, Matthew J. Hurley, Nicholas Leonard, Rebecca B. Wai, Jenna A. Tan, Mumtaz Gababa, Chenhui Zhu, Eric Schaible, Christopher J. Tassone, David T. Limmer, Samuel W. Teitelbaum, Dmitri V. Talapin, Naomi S. Ginsberg
Achieving predictive control over crystallization using non-classical nucleation while avoiding kinetic traps would be a step towards designing materials with new functionalities. We address these challenges by inducing the bottom-up assembly of nanocrystals into ordered arrays, or superlattices. Using electrostatics–rather than density–to tune the interactions between particles, we watch self-assembly proceed through a metastable liquid phase. We systematically investigate the phase behaviour as a function of quench conditions in situ and in real time using small-angle X-ray scattering. By fitting to colloid, liquid and superlattice models, we extract the time evolution of each phase and the system phase diagram, which we find to be consistent with short-range attractive interactions. Using the predictive power of the phase diagram, we establish control of the self-assembly rate over three orders of magnitude, and we identify one- and two-step self-assembly regimes, with only the latter implicating the metastable liquid as an intermediate. The presence of the metastable liquid increases the superlattice formation rate relative to the equivalent one-step pathway, and the superlattice order increases with the rate, revealing a generalizable kinetic strategy for promoting and enhancing ordered assembly.
Characterization and analytical techniques, Nanoparticles, Phase transitions and critical phenomena, Synthesis and processing
Nature Reviews Materials
Coordination chemistry in advanced redox-active electrolyte designs
Review Paper | Batteries | 2025-08-25 20:00 EDT
Fei Ai, Yi-Chun Lu
Coordination chemistry is central to the development of redox-active electrolytes for various applications, including electroplating, molecular screening, biomedicine, artificial synthesis and energy storage. This Review focuses on the role of coordination chemistry in the design of redox-active electrolytes for aqueous redox flow batteries. We analyse the key thermodynamic and kinetic properties of electrolytes through the framework of crystal-field theory, emphasizing how ligand properties, ligand-field effects and entropy influence redox potential, solubility and structural stability. We also discuss how coordination chemistry fine-tunes microscopic dynamic properties, thereby influencing electrochemical performance. In addition, we discuss characterization techniques that enable deep insight into the structure-function relationships of coordination-based electrolytes. Finally, we outline future directions for rational electrolyte design guided by coordination chemistry principles, with the aim to produce next-generation aqueous redox flow batteries with enhanced performance and tunability.
Batteries, Materials for energy and catalysis
Physical Review Letters
Probing Topological Entanglement on Large Scales
Research article | Entanglement in field theory | 2025-08-25 06:00 EDT
Robert Ott, Torsten V. Zache, Nishad Maskara, Mikhail D. Lukin, Peter Zoller, and Hannes Pichler
Topologically ordered quantum matter exhibits intriguing long-range patterns of entanglement, which reveal themselves in subsystem entropies. However, measuring such entropies, which can be used to certify topological order, on large partitions is challenging and becomes practically unfeasible for large systems. We propose a protocol based on local adiabatic deformations of the Hamiltonian which extracts the universal features of long-range topological entanglement from measurements on small subsystems of finite size, trading an exponential number of measurements against a polynomial-time evolution. Our protocol is general and readily applicable to various quantum simulation architectures. We apply our method to various string-net models representing both Abelian and non-Abelian topologically ordered phases and illustrate its application to neutral atom tweezer arrays with numerical simulations.
Phys. Rev. Lett. 135, 090401 (2025)
Entanglement in field theory, Order parameters, Quantum entanglement, Quantum phase transitions, Quantum simulation, Topological order
Error-Corrected Fermionic Quantum Processors with Neutral Atoms
Research article | Fermi gases | 2025-08-25 06:00 EDT
Robert Ott, Daniel González-Cuadra, Torsten V. Zache, Peter Zoller, Adam M. Kaufman, and Hannes Pichler
Many-body fermionic systems can be simulated in a hardware-efficient manner using a fermionic quantum processor. Neutral atoms trapped in optical potentials can realize such processors, where nonlocal fermionic statistics are guaranteed at the hardware level. Implementing quantum error correction in this setup is, however, challenging, due to the atom-number superselection present in atomic systems, that is, the impossibility of creating coherent superpositions of different particle numbers. In this Letter, we overcome this constraint and present a blueprint for an error-corrected fermionic quantum processor that can be implemented using current experimental capabilities. To achieve this, we first consider an ancillary set of fermionic modes and design a fermionic reference, which we then use to construct superpositions of different numbers of referenced fermions. This allows us to build logical fermionic modes that can be error corrected using standard atomic operations. Here, we focus on phase errors, which we expect to be a dominant source of errors in neutral-atom quantum processors. We then construct logical fermionic gates, and show their implementation for the logical particle-number conserving processes relevant for quantum simulation. Finally, our protocol is illustrated with a minimal fermionic circuit, where it leads to a quadratic suppression of the logical error rate.
Phys. Rev. Lett. 135, 090601 (2025)
Fermi gases, Fermions, Quantum error correction, Quantum simulation, Atoms, Rydberg atoms & molecules, Trapped atoms, Optical lattices & traps
First Measurement of the Decay Dynamics in the Semileptonic Transition of ${\mathrm{D}}^{+(0)}$ into the Axial-Vector Meson ${\overline{K}}_{1}(1270)$
Research article | Cabibbo-Kobayashi-Maskawa matrix | 2025-08-25 06:00 EDT
M. Ablikim et al. (BESIII Collaboration)
Using ${e}^{+}{e}^{- }$ data taken at the center-of-mass energy of 3.773 GeV with the BESIII detector, corresponding to an integrated luminosity of $20.3\text{ }\text{ }{\mathrm{fb}}^{- 1}$, we report the first measurement of the decay dynamics of the semileptonic decays ${D}^{+(0)}\rightarrow {K}^{- }{\pi }^{+}{\pi }^{0(- )}{e}^{+}{\nu }{e}$. The amplitude analysis gives the hadronic form factors of the semileptonic $D$ transitions into the axial-vector meson ${\overline{K}}{1}(1270)$ to be ${r}{A}=(- 11.2\pm{}{1.0}{\mathrm{stat}}\pm{}{0.9}{\mathrm{syst}})\times{}{10}^{- 2}$ and ${r}{V}=(- 4.3\pm{}{1.0}{\mathrm{stat}}\pm{}{2.5}{\mathrm{syst}})\times{}{10}^{- 2}$. This is the first in the semileptonic decays of heavy mesons into axial-vector mesons. The angular analysis yields an up-down asymmetry ${\mathcal{A}}{\mathrm{ud}}^{‘ }=0.01\pm{}0.11$, which is consistent with the standard model prediction. In addition, the branching fractions of ${D}^{+}\rightarrow {\overline{K}}{1}(1270{)}^{0}{e}^{+}{\nu }{e}$ and ${D}^{0}\rightarrow {K}{1}(1270{)}^{- }{e}^{+}{\nu }{e}$ are determined with improved precision to be $(2.27\pm{}0.1{1}{\mathrm{stat}}\pm{}0.0{7}{\mathrm{syst}}\pm{}0.0{7}{\text{input}})\times{}{10}^{- 3}$ and $(1.02\pm{}0.0{6}{\mathrm{stat}}\pm{}0.0{6}{\mathrm{syst}}\pm{}0.0{3}{\text{input}})\times{}{10}^{- 3}$, respectively. No significant signals of ${D}^{+}\rightarrow {\overline{K}}{1}(1400{)}^{0}{e}^{+}{\nu }{e}$ and ${D}^{0}\rightarrow {K}{1}(1400{)}^{- }{e}^{+}{\nu }_{e}$ are observed and their branching fraction upper limits are set as $1.4\times{}{10}^{- 4}$ and $0.7\times{}{10}^{- 4}$ at 90% confidence level, respectively.
Phys. Rev. Lett. 135, 091801 (2025)
Cabibbo-Kobayashi-Maskawa matrix, Form factors, Charmed mesons
Measurement of $WWZ$ and $ZH$ Production Cross Sections at $\sqrt{s}=13$ and 13.6 TeV
Research article | Gauge bosons | 2025-08-25 06:00 EDT
A. Hayrapetyan et al. (CMS Collaboration)
A measurement is presented of the cross section in proton-proton collisions for the production of two $W$ bosons and one $Z$ boson. It is based on data recorded by the CMS experiment at the CERN LHC at center-of-mass energies $\sqrt{s}=13$ and 13.6 TeV, corresponding to an integrated luminosity of $200\text{ }\text{ }{\mathrm{fb}}^{- 1}$. Events with four charged leptons (electrons or muons) in the final state are selected. Both nonresonant $WWZ$ production and $ZH$ production, with the Higgs boson decaying into two $W$ bosons, are reported. For the first time, the two processes are measured separately in a simultaneous fit. Combining the two modes, signal strengths relative to the standard model (SM) predictions of ${0.75}{- 0.29}^{+0.34}$ and ${1.74}{- 0.60}^{+0.71}$ are measured for $\sqrt{s}=13$ and 13.6 TeV, respectively. The observed (expected) significance for the triboson signal is 3.8 (2.5) standard deviations for $\sqrt{s}=13.6\text{ }\text{ }\mathrm{TeV}$, thus providing the first evidence for triboson production at this center-of-mass energy. Combining the two modes and the two center-of-mass energies, the inclusive signal strength relative to the SM prediction is measured to be ${1.03}_{- 0.28}^{+0.31}$, with an observed (expected) significance of 4.5 (5.0) standard deviations.
Phys. Rev. Lett. 135, 091802 (2025)
Gauge bosons, Higgs bosons, Hadron colliders
Observation of the Charged-Particle Multiplicity Dependence of ${\sigma }{\psi (2S)}/{\sigma }{J/\psi }$ in $p$-Pb Collisions at 8.16 TeV
Research article | Relativistic heavy-ion collisions | 2025-08-25 06:00 EDT
V. Chekhovsky et al. (CMS Collaboration)
Bound states of charm and anticharm quarks, known as charmonia, have a rich spectroscopic structure that can be used to probe the dynamics of hadron production in high-energy hadron collisions. Here, the cross section ratio of excited $(\psi (2S))$ and ground state $(J/\psi )$ vector mesons is measured as a function of the charged-particle multiplicity in proton-lead ($p\mathrm{Pb}$) collisions at a center-of-mass (CM) energy per nucleon pair of 8.16 TeV. The data corresponding to an integrated luminosity of $175\text{ }\text{ }{\mathrm{nb}}^{- 1}$ were collected using the CMS detector. The ratio is measured separately for prompt and nonprompt charmonia in the transverse momentum range $6.5<{p}{\mathrm{T}}<30\text{ }\text{ }\mathrm{GeV}$ and in four rapidity ranges spanning $- 2.865<{y}{\mathrm{CM}}<1.935$. For the first time, a statistically significant multiplicity dependence of the prompt cross section ratio is observed in proton-nucleus collisions. There is no clear rapidity dependence in the ratio. The prompt measurements are compared with a theoretical model which includes interactions with nearby particles during the evolution of the system. These results provide additional constraints on hadronization models of heavy quarks in nuclear collisions.
Phys. Rev. Lett. 135, 092301 (2025)
Relativistic heavy-ion collisions, Charm quark, Quarkonia, Hadron colliders
Vortex Nucleations in Spinor Bose Condensates under Localized Synthetic Magnetic Fields
Research article | Bose-Einstein condensates | 2025-08-25 06:00 EDT
L.-R. Liu, S.-C. Wu, T.-W. Liu, H.-Y. Hsu, T.-K. Shen, S.-K. Yip, Y. Kawaguchi, and Y.-J. Lin
Gauge fields are ubiquitous in modern quantum physics. In superfluids, quantized vortices can be induced by gauge fields. Here we demonstrate the first experimental observation of vortex nucleations in light-dressed spinor Bose-Einstein condensates under radially localized synthetic magnetic fields. The light-induced spin-orbital-angular-momentum coupling creates azimuthal gauge potentials $\stackrel{\rightarrow }{A}$ for the lowest-energy spinor branch dressed eigenstate. The observation of the atomic wave function in the lowest-energy dressed eigenstate reveals that vortices nucleate from the cloud center of a vortex-free state with canonical momentum $\stackrel{\rightarrow }{p}=0$. This is because a large circulating azimuthal velocity field $\propto \stackrel{\rightarrow }{p}- \stackrel{\rightarrow }{A}$ at the condensate center results in a dynamically unstable localized excitation that initiates vortex nucleations. Furthermore, the long-time dynamics to reach the ground state stops in a metastable state when $|\stackrel{\rightarrow }{A}|$ is not sufficiently large. Our observation has reasonable agreement with the time-dependent Gross-Pitaevskii simulations.
Phys. Rev. Lett. 135, 093401 (2025)
Bose-Einstein condensates, Spin-orbit coupling, Synthetic gauge fields
Unified Phenomenology and Test-Particle Simulations of Ion Heating in Low-$\beta $ Plasmas
Research article | Plasma turbulence | 2025-08-25 06:00 EDT
Zade Johnston, Jonathan Squire, and Romain Meyrand
We argue that stochastic and resonant ion heating, often viewed as distinct processes in low-$\beta $ collisionless plasmas, are the far limits of a continuum controlled by nonlinear broadening of turbulent fluctuations, and thus by the normalized cross helicity. We propose a simple empirical formula that captures both regimes, generalizing the model commonly used to describe stochastic heating. Simulations of test ions interacting with turbulence confirm our scalings across a wide range of different ion and turbulence properties, including with a steep ion-kinetic transition range as seen in the solar wind. Our results provide a unified framework for understanding ion heating processes across diverse astrophysical environments from black-hole accretion disks to the solar corona, also providing a compact and versatile subgrid model for larger-scale simulations.
Phys. Rev. Lett. 135, 095201 (2025)
Plasma turbulence, Space & astrophysical plasma, Solar corona, Solar wind, Test-particle methods
Evidence for the Meissner Effect in the Nickelate Superconductor ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}_{7\text{- }\delta }$ Single Crystal Using Diamond Quantum Sensors
Research article | Methods in superconductivity | 2025-08-25 06:00 EDT
Lin Liu, Jianning Guo, Deyuan Hu, Guizhen Yan, Yuzhi Chen, Lunxuan Yu, Meng Wang, Xiao-Di Liu, and Xiaoli Huang
Quantum sensing with nitrogen-vacancy (NV) centers in diamond enables the characterization of magnetic properties in the extreme situation of a tiny sample with defects. Recent studies have reported superconductivity in ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}{7\text{- }\delta }$ under pressure, with zero resistance near 80 K, though the Meissner effect remains debated due to low superconducting volume fractions and limited high-pressure magnetic measurement techniques. In this work, we use diamond quantum sensors and four-probe detection to observe both zero resistance and the Meissner effect in the same ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}{7\text{- }\delta }$ single crystal. By mapping the Meissner effect, we visualized superconducting regions and revealed sample inhomogeneities. Our combined magnetic and electrical measurements on the same crystal provide dual evidence of superconductivity, supporting the high-temperature superconductivity of ${\mathrm{La}}{3}{\mathrm{Ni}}{2}{\mathrm{O}}_{7\text{- }\delta }$. This study also offers insights into its structural and magnetic properties under high pressure.
Phys. Rev. Lett. 135, 096001 (2025)
Methods in superconductivity
Nature of Metallic and Insulating Domains in the Charge-Density-Wave System $1{\mathrm{T}\text{- }\mathrm{TaSe}}_{2}$
Research article | Charge density waves | 2025-08-25 06:00 EDT
M. Straub, F. Petocchi, C. Witteveen, F. B. Kugler, A. Hunter, Y. Alexanian, G. Gatti, S. Mandloi, C. Polley, G. Carbone, J. Osiecki, F. O. von Rohr, A. Georges, F. Baumberger, and A. Tamai
We study the electronic structure of bulk $1{\mathrm{T}\text{- }\mathrm{TaSe}}{2}$ in the charge-density wave phase at low temperature. Our spatially and angle-resolved photoemission data show insulating areas coexisting with metallic regions characterized by a chiral Fermi surface and moderately correlated quasiparticle bands. Additionally, high-resolution laser angle-resolved photoemission reveals variations in the metallic regions, with series of low-energy states, whose energy, number, and dispersion can be explained by the formation of quantum well states of different thicknesses. Dynamical mean field theory calculations show that the observed rich behavior can be rationalized by assuming occasional stacking faults of the charge density wave. Our results indicate that the diverse electronic phenomena reported previously in $1{\mathrm{T}\text{- }\mathrm{TaSe}}{2}$ are dictated by the stacking arrangement and the resulting quantum size effects while correlation effects play a secondary role.
Phys. Rev. Lett. 135, 096501 (2025)
Charge density waves, Electronic structure, Mott insulators, Strongly correlated systems, Transition metal dichalcogenides, Angle-resolved photoemission spectroscopy, DFT+DMFT
Field-Driven Band Asymmetry and Nonreciprocal Transport in a Helimagnet
Research article | Electrical conductivity | 2025-08-25 06:00 EDT
Darius-Alexandru Deaconu, Aneesh Agarwal, Rodion Vladimirovich Belosludov, Robert-Jan Slager, and Mohammad Saeed Bahramy
Helimagnets exhibit noncollinear spin arrangements characterized by a periodic helical modulation, giving rise to emergent chiral properties. These materials have attracted significant interest due to their potential applications in spintronics, particularly for robust information storage and the realization of topological spin textures such as skyrmions. In this work, we focus on Yoshimori-type helimagnets, where competing exchange interactions mediated by conduction electrons stabilize helical spin structures without requiring Dzyaloshinskii-Moriya interaction. We introduce a minimal model describing the electronic structure of a one-dimensional helimagnet in the presence of an external magnetic field and investigate its impact on nonreciprocal transport. We demonstrate how band asymmetry emerges in the conical phase induced by the external field, leading to a nonzero second-order electronic conductivity and injection photoconductivity. Our results provide insight into the interplay between the real space magnetic texture and electronic properties, paving the way for future studies on chirality-driven transport phenomena in centrosymmetric helimagnets.
Phys. Rev. Lett. 135, 096701 (2025)
Electrical conductivity, Magnetic phase transitions, RKKY interaction, Spintronics, Chiral magnets, Helimagnets, Boltzmann theory, Tight-binding model
Physical Review X
Relativistic Linear Response in Quantum-Electrodynamical Density Functional Theory
Research article | Cavity quantum electrodynamics | 2025-08-25 06:00 EDT
Lukas Konecny, Valeriia P. Kosheleva, Heiko Appel, Michael Ruggenthaler, and Angel Rubio
A new theoretical framework combines strong light-matter coupling with relativistic quantum effects, revealing how optical cavities can control spin-orbit interactions and modify formally forbidden transitions in heavy atoms.
Phys. Rev. X 15, 031052 (2025)
Cavity quantum electrodynamics, Density functional theory, Electronic transitions, Light-matter interaction, Relativistic & quantum electrodynamic effects in atoms, molecules,& ions, Spin-orbit coupling
Quantum Storage of Qubits in an Array of Independently Controllable Solid-State Quantum Memories
Research article | Light stopping & storage | 2025-08-25 06:00 EDT
Markus Teller, Susana Plascencia, Samuele Grandi, and Hugues de Riedmatten
An array of ten independently controlled quantum memory cells stores photonic qubits in a rare-earth crystal, advancing the development of scalable, RAM-like storage for photonic quantum computing.
Phys. Rev. X 15, 031053 (2025)
Light stopping & storage, Quantum engineering, Quantum memories, Quantum state transfer
Review of Modern Physics
Nobel Lecture: Physics is a point of view
Oration | | 2025-08-25 06:00 EDT
John J. Hopfield
The 2024 Nobel Prize for Physics was shared by John Hopfield and Geoffrey Hinton. This paper is the text of the address given in conjunction with the award.
Rev. Mod. Phys. 97, 030501 (2025)
Nobel Lecture: Boltzmann machines
Oration | Artificial neural networks | 2025-08-25 06:00 EDT
Geoffrey Hinton
The 2024 Nobel Prize for Physics was shared by John Hopfield and Geoffrey Hinton. This paper is the text of the address given in conjunction with the award.
Rev. Mod. Phys. 97, 030502 (2025)
Artificial neural networks
arXiv
Phase field modelling of the growth and detachment of bubbles in a hydrogen electrolyzer
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Carlos Uriarte, Marco A. Fontelos, Manuel Arrayás
We develop and implement numerically a phase field model for the growth and detachment of a gas bubble resting on an electrode and being filled with hydrogen produced by water electrolysis. The bubble is surrounded by a viscous liquid, has a prescribed static contact angle and is also subject to gravitational forces. We compute, as a function of the static contact angle, the time at which the bubble detaches from the substrate and what volume it has at that time. We also investigate de dependence of the detachment time on other parameters such as the applied voltage and the hydrogen ion concentration at the fluid bulk.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Fluid Dynamics (physics.flu-dyn)
Sequence-Defined Phase Behavior of Poly(N-Isopropylacrylamide-co-Acrylamide) in Water
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Sandeep Parma, R. Nagaranajan, Tarak K Patra
The precise arrangement of different chemical moieties in a polymer determines its thermophysical properties. How the sequence of moieties impacts the properties of a polymer is an outstanding problem in polymer science. Herein, we address this problem for the thermoresponsive property of poly(N-isopropylacrylamide-co-acrylamide) in water using all-atom molecular dynamics (MD) simulations. Eight distinct copolymers, each with a different arrangement of NIPAM(N-isopropylacrylamide) and AM (acrylamide) monomers, are considered. The lower critical solution temperature (LCST) shows a strong correlation with the mean block length of the periodic sequences of the copolymer. We further identify copolymer sequences that exhibit both the LCST and upper critical solution temperature (UCST). Moreover, there are sequences that do not show any LCST or UCST for the temperature range explored in this study. This wide variability in thermorepsonsive property is found to be closely linked to the the extent of hydrongen bond formation in the system, which appears to have a significant correlation with the monomer sequence of the copolymer. These findings offer new directions in the design of structurally diverse thermoresponsive copolymers.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
A Universal Thermodynamic Inequality: Scaling Relations Between Current, Activity, and Entropy Production
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-26 20:00 EDT
We derive a universal thermodynamic bound constraining directional transport in both discrete and continuous nonequilibrium systems. For continuous-time Markov jump processes and overdamped diffusions governed by Fokker–Planck equations, we prove the inequality $ \frac{2 V(t)^2}{A(t)} \leq \dot{e}_p(t), $ linking the squared net velocity $ V(t)$ , entropy production rate $ \dot{e}_p(t)$ , and dynamical activity $ A(t)$ . This relation captures a fundamental trade-off between transport, dissipation, and fluctuation intensity, valid far from equilibrium and without detailed balance. In addition, we introduce dimensionless thermodynamic ratios that quantify dissipation asymmetry, entropy extraction, and relaxation. These scaling laws unify discrete and continuous stochastic thermodynamics and provide experimentally accessible constraints on transport efficiency in nanoscale machines and active systems.
Statistical Mechanics (cond-mat.stat-mech)
5 pages
Hunting for superconductivity in doped triangular lattice Kitaev magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Andrew Hardy, Ryan Levy, Arun Paramekanti
Motivated by exploring correlated metals with frustrating bond-dependent exchange interactions, we study hole and electron doped Kitaev Mott insulators on the triangular lattice. Using homogeneous parton mean field theory, we find that the stripe antiferromagnetic (AFM) order for Kitaev coupling $ K>0$ and the ferromagnetic (FM) order for $ K<0$ , both vanish at sufficiently large doping, beyond which we find regimes with chiral $ d\pm i d$ singlet pairing and $ p\pm ip$ triplet pairing respectively. Our tensor network computations however reveal that the superconducting correlations are strongly suppressed; while FM order stubbornly persists for the doped $ K<0$ model, the doped $ K>0$ model features emergent spin-charge modulated stripe orders. At higher hole doping for $ K > 0$ , where AFM order is more strongly suppressed than for the electron doped case, incorporating a sufficiently strong nearest-neighbor attraction yields evidence for singlet $ d$ -wave superconductivity with Luttinger parameter $ K_{\rm sc} < 1$ . Our work sets the stage for a broader exploration of doping effects in triangular lattice magnets such as NaRuO$ _2$ which feature bond-dependent exchange interactions.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
4 pages, 5 figures, with additional supplemental material and figures
Unnecessary quantum criticality in $SU(3)$ kagome magnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Yunchao Zhang, Xue-Yang Song, T. Senthil
Algebraic/Dirac spin liquids (DSLs) are a class of critical quantum ground states that do not have a quasi-particle description. DSLs and related spin liquid phases often arise in strongly frustrated quantum spin systems, in which strong correlations and quantum fluctuations among constituent spins persist down to zero temperature. In this work, we analyze Mott insulating phases of $ SU(3)$ fermions on a kagome lattice which may realize a DSL phase, described at low energies by $ (2 + 1)d$ quantum electrodynamics (QED$ _3$ ) with $ N_f=6$ Dirac fermions. By analyzing the action of physical symmetries on the operators of the QED$ _3$ theory, we conclude that the low energy DSL is a quantum critical point that can be accessed by tuning a single microscopic parameter. Aided by the emergent symmetry and anomalies of the low energy effective theory, we conjecture and present supporting arguments that the $ SU(3)$ Kagome magnet DSL is an unnecessary quantum critical point, lying completely within a single phase.
Strongly Correlated Electrons (cond-mat.str-el)
19 pages, 3 figures
Electronic correlation effects in the response of graphene and MoS2 monolayers to the impact of highly-charged ions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Giorgio Lovato, Michael Bonitz, Karsten Balzer, Fabio Caruso, Jan-Philip Joost
The interaction of highly-charged ions with monolayers of graphene and MoS2 is theoretically investigated based on nonequilibrium Green Functions (NEGF). In a recent paper [Niggas et al., Phys. Rev. Lett. 129, 086802 (2022)] dramatic differences in the response of the two materials to an impacting slow ion were reported. Here, this analysis is extended, focusing on the effect of electron-electron correlations in the monolayer on the electronic response to the ion. We apply the recently developed time-linear G1-G2 scheme [Schluenzen et al., Phys. Rev. Lett. 124, 076601 (2020)] combined with an embedding approach [Balzer et al., Phys. Rev. B 107, 155141 (2023)]. We demonstrate that, while electronic correlations have a minor effect in graphene, they significantly influence the electron dynamics in the case of MoS2. Our key results are the ultrafast dynamics of the charge density and induced electrostatic potential in the vicinity of the impact point of the ion.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
25 pages, 11 figures
Spontaneous spiral patterns etched on Germanium
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Thin metal film on Germanium, in the presence of water, results in a remarkable pattern forming system. Here we present an analysis of spirals spontaneously etched on the Ge surface. We obtain measurements of the growth dynamics of the spirals and measurements of the local strain field in the metal film. Both indicate that the near geometric order of the pattern originates from the unique far field of a singularity - a crystal defect. The measured engraving profile is found in quantitative agreement with a model of metal catalyzed corrosion of the Ge surface. Specifically, local etch depth is inversely proportional to the normal velocity of the Ge-metal contact line. The growth mechanism combines crack propagation, reaction diffusion dynamics, and thin film mechanical instabilities, and illustrates how a defect’s long range field can impose geometric order in a non-equilibrium growth process. General features relevant to other pattern forming systems are the coupling of chemistry and mechanics and the singularity driven order.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph)
13 pages, 15 figures
Enhanced Performance of FeFET Gate Stack via Heterogeneously co-doped Ferroelectric HfO$_2$ Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Shouzhuo Yang, David Lehninger, Peter Reinig, Fred Schöne, Raik Hoffmann, Konrad Seidel, Maximilian Lederer, Gerald Gerlach
In this work, we explore the impact of spatially controlled Zr and Al heterogeneous co-doping in HfO$ _2$ thin films tailored for metal-ferroelectric-insulator-semiconductor (MFIS) gate stacks of ferroelectric field effect transistors (FeFETs). By precisely modulating the vertical arrangement of Zr and Al dopants during atomic layer deposition, we introduce deliberate compositional gradients that affect crystallization dynamics during subsequent annealing. This strategy enables us to systematically tune the phase evolution and domain nucleation within the ferroelectric layer, directly influencing device reliability and performance. From a structural perspective, our findings demonstrate that the phase composition of annealed HfO$ _2$ films in MFIS stacks is primarily determined by the spatial arrangement of dopants. From an electrical perspective, we observe significant enhancement of remanent polarization and endurance of the gate stacks through heterogeneous co-doping, depending on the spatial arrangement of dopants.
Materials Science (cond-mat.mtrl-sci)
6 pages, 7 figures
A shear cell study on oral and inhalation grade lactose powders
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Giulio Cavalli, Roberto Bosi, Alessandro Ghiretti, Ciro Cottini, Andrea Benassi, Roberto Gaspari
Shear cell tests have been conducted on twenty different lactose powders, most of which commercially available for oral or inhalation purposes, spanning a wide range of particle sizes, particle morphologies, production processes. The aims of the investigation were: i) to verify the reliability of the technique in evaluating and classifying the flowability of powders; ii) to understand the connection between the flowability of a powder and the morphological properties of its particles; iii) to find a general mathematical relationship able to predict the yield locus shape given the particle size, shape and consolidation state of a lactose powder. These aspects and their limitations are detailed in the manuscript together with other interesting findings on the stick-slip behavior observed in most of the lactose powders examined.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph)
Powder Technology 372 (2020) 117-127
Molecular Tools for Non-Planar Surface Chemistry
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Taleana Huff, Brandon Blue, Terry McCallum, Mathieu Morin, Damian G. Allis, Rafik Addou, Jeremy Barton, Adam Bottomley, Doreen Cheng, Nina M. Ćulum, Michael Drew, Tyler Enright, Alan T.K. Godfrey, Ryan Groome, Aru J. Hill, Alex Inayeh, Matthew R. Kennedy, Robert J. Kirby, Mykhaylo Krykunov, Sam Lilak, Hadiya Ma, Cameron J. Mackie, Oliver MacLean, Jonathan Myall, Ryan Plumadore, Adam Powell, Henry Rodriguez, Luis Sandoval, Marc Savoie, Benjamin Scheffel, Marco Taucer, Denis A.B. Therien, Dušan Vobornik
Scanning probe microscopy (SPM) investigations of on-surface chemistry on passivated silicon have only shown in-plane chemical reactions, and studies on bare silicon are limited in facilitating additional reactions post-molecular-attachment. Here, we enable subsequent reactions on Si(100) through selectively adsorbing 3D, silicon-specific “molecular tools”. Following an activation step, the molecules present an out-of-plane radical that can function both to donate or accept molecular fragments, thereby enabling applications across multiple scales, e.g., macroscale customizable silicon-carbon coatings or nanoscale tip-mediated mechanosynthesis. Creation of many such molecular tools is enabled by broad molecular design criteria that facilitate reproducibility, surface specificity, and experimental verifiability. These criteria are demonstrated using a model molecular tool tetrakis(iodomethyl)germane ($ Ge(CH_{2}I)_{4}$ ; TIMe-Ge), with experimental validation by SPM and X-ray photoelectron spectroscopy (XPS), and theoretical support by density functional theory (DFT) investigations. With this framework, a broad and diverse range of new molecular engineering capabilities are enabled on silicon.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Atomic Physics (physics.atom-ph), Chemical Physics (physics.chem-ph)
Manuscript is pages 1-37, 4 Figures. Supplementary Information is pages 38-86, with 24 Figures
On the Relationship and Distinction Between Atomic Density and Coordination Number in Describing Grain Boundaries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Reza Darvishi Kamachali, Theophilus Wallis
Crystal defects are often rationalized through broken-bond counting via the nearest neighbor coordination number. In this work, we highlight that this perspective overlooks intrinsic heterogeneities in interatomic spacing that decisively shape defect properties. We analyze excess free volume, energy, and entropy for a large set of BCC-Fe grain boundaries relaxed by molecular statics and demonstrate that an atomic-density field, as a systematically coarse-grained field variable, provides a more comprehensive descriptor. Unlike coordination alone, the density field simultaneously captures bond depletion and spacing variations, thereby unifying structural and volumetric information. Our results establish density-based descriptors as principled surrogates for grain-boundary thermodynamics and kinetics, offer a direct bridge from atomistic data to mesoscale models, and motivate augmenting broken-bond rules in predictive theories of interfacial energetics, excess properties, segregation and phase behavior.
Materials Science (cond-mat.mtrl-sci)
9 pages, 6 figures, letter
Memory-aware feedback enhances power in active information engines
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-26 20:00 EDT
Sehoon Bahng, Jae Sung Lee, Cheol-Min Ghim
We study an information engine operating in an active bath, where a Brownian particle confined in a harmonic trap undergoes feedback-driven displacement cycles. Unlike thermal environments, active baths exhibit temporally correlated fluctuations, introducing memory effects that challenge conventional feedback strategies. Extending the framework of stochastic thermodynamics to account for such memory, we analyze a feedback protocol that periodically shifts the potential minimum based on noisy measurements of the particle’s position. We show that conventional feedback schemes, optimized for memoryless thermal baths, can degrade performance in active media due to the disruption of bath-particle memory by abrupt resetting. To overcome this degradation, we introduce a class of memory-preserving feedback protocols that partially retain the covariance between the particle’s displacement and active noise, thereby exploiting the temporal persistence of active fluctuations. Through asymptotic analysis, we show how the feedback gain – which quantifies the strength of positional shifts – nontrivially shapes the engine’s work and power profiles. In particular, we demonstrate that in active media, intermediate gains outperform full-shift resetting. Our results reveal the critical interplay between bath memory, measurement noise, and feedback gain, offering guiding principles for designing high-performance information engines in nonequilibrium environments.
Statistical Mechanics (cond-mat.stat-mech)
Identifying the magnetic genes in fully- and partially-ordered V$_2$$X$Al ($X$ = Cr, Mn, Fe, Co, Ni) Heusler alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Zhenyang Xie, Yuntao Wu, Jitong Song, Yuanji Xu, Fuyang Tian
Multicomponent Heusler alloys exhibit various magnetic properties arising from their diverse atomic compositions and crystal structures. Identifying the general physical principles that govern these behaviors is essential for advancing their potential in spintronic applications. In this work, we combine density functional theory with atomistic Monte Carlo simulations to investigate the magnetic ground states, finite-temperature magnetic transitions, and electronic structures of fully-ordered $ L2_1$ -, $ XA$ -type, and partially-ordered V$ 2X$ Al ($ X=$ Cr, Mn, Fe, Co, Ni) Heusler alloys. We introduce the concept of magnetic genes, defined as V-$ X$ -V triangular motifs connected by the nearest-neighbor (NN) exchange interactions $ J{\mathrm{V-}X}$ . Within this framework, the magnetic ground states and transition temperatures across the V$ 2X$ Al family can be consistently understood. The magnetic order is primarily governed by the NN $ J{\mathrm{V-}X}$ interactions in the triangular genes, while the transition temperatures are additionally influenced by $ J_{X-X}$ couplings. Furthermore, the magnetic genes are still proven to be effective in our calculations on partially-ordered V$ _2$ X$ Al alloys from $ L2_1$ to $ XA$ -type structures. Our results suggest that the concept of magnetic genes provides a unifying principle for understanding magnetic ordering in V-based Heusler alloys and could serve as a powerful guide for exploring magnetism and designing advanced spintronic materials in a broader class of Heusler systems.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Phonon anharmonicity-driven charge density wave transition and ultrafast dynamics in 1T-TaS2/TaSe2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Wenqian Tu, Run Lv, Dingfu Shao, Yuping Sun, Wenjian Lu
Charge density wave (CDW), a symmetry-breaking collective phenomenon in condensed matter systems, exhibits periodic modulations of electron density coupled with lattice distortions, where the lattice plays a critical role via electron-phonon coupling. In transition metal dichalcogenides (TMDs) 1T-TaS2/TaSe2, experiments reveal rich temperature- and pressure-dependent CDW phase behaviors, along with metastable CDW states induced by ultrafast optical excitation. Nevertheless, the underlying mechanisms governing thermal/pressure-driven transitions and particularly the microscopic evolution of CDW phases remain incompletely understood. Here, we perform first-principles anharmonic phonon calculations and machine-learning force-field molecular dynamics at finite temperatures/pressures to investigate the CDW transitions in 1T-TaS2/TaSe2. The calculated CDW transition temperature TCDW and critical pressure Pc are in quantitative agreement with experimental values. Our results demonstrate that the melting of CDW originates from phonon anharmonicity, with ionic fluctuations dominating the transition dynamics. We observe the microscopic evolution of CDW under varying temperature/pressure, revealing an ultrafast nucleation process of CDW (~3 ps). Our results emphasize the essential role of phonon anharmonicity in elucidating CDW transition mechanisms underlying, and advance fundamental understanding of CDW-related phenomena in TMDs.
Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
Electrostatic gating and the interference of chiral Majoranas in thin slabs of magnetic topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
We study the interference of chiral Majoranas in a magnetic topological insulator thin slab having a grounded section proximity coupled to a superconductor and another section under the influence of top-bottom electrostatic gating. The gated section locally widens an energy gap and mediates the coupling between the quantum anomalous Hall states of the leads and the chiral Majorana states of the proximitized sector. Local and non-local conductances offer measurable hints of the existence of transport mediated by chiral Majorana modes. Local conductances on the two leads reveal characteristic oscillatory patterns as a function of the gating strength, with peculiar correlations depending on the distance between gated and proximitized sectors. A gate tunable Majorana diode effect on nonlocal conductances emerges when the chemical potential deviates from zero. We suggest a protocol to identify chiral Majorana physics based on a sequence of electrostatic gates that allows the tuning of chiral Majorana interference.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 8 figures
Three-dimensional unfrustrated and frustrated quantum Heisenberg magnets. Specific heat study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Taras Krokhmalski, Taras Hutak, Oleg Derzhko
We examine the $ S=1/2$ Heisenberg magnet on four three-dimensional lattices – simple-cubic, diamond, pyrochlore, and hyperkagome ones – for ferromagnetic and antiferromagnetic signs of the exchange interaction in order to illustrate the effect of lattice geometry on the finite-temperature thermodynamic properties with a focus on the specific heat $ c(T)$ . To this end, we use quantum Monte Carlo simulations or high-temperature expansion series complemented with the entropy method. We also discuss a recent proposal about hidden energy scale in geometrically frustrated magnets.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
10 pages, 7 figures
A Single-Molecule Quantum Heat Engine
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Serhii Volosheniuk, Riccardo Conte, Eugenia Pyurbeeva, Thomas Baum, Manuel Vilas-Varela, Saleta Fernández, Diego Peña, Herre S.J. van der Zant, Pascal Gehring
Particle-exchange heat engines operate without moving parts or time-dependent driving, relying solely on static energy-selective transport. Here, we realize a particle-exchange quantum heat engine based on a single diradical molecule, only a few nanometers in size. We experimentally investigate its operation at low temperatures and demonstrate that both the power output and efficiency are significantly enhanced by Kondo correlations, reaching up to 53 % of the Curzon-Ahlborn limit. These results establish molecular-scale particle-exchange engines as promising candidates for low-temperature applications where extreme miniaturization and energy efficiency are paramount.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Particle-hole Symmetric Slave Boson Method for the Mixed Valence Problem
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
We introduce an analytic slave boson method for treating the finite $ U$ Anderson impurity model. Our approach introduces two bosons to track both $ Q\rightleftharpoons Q\pm1$ valence fluctuations and reduces to a single symmetric $ s$ -boson in the effective action, encoding all the high energy atomic physics information in the boson’s kinematics, while the low energy part of the action remains unchanged across finite $ U$ , infinite $ U$ , and Kondo limits. We recover the infinite $ U$ and Kondo limit actions from our approach and show that the Kondo resonance already develops in the normal state when the slave boson has yet to condense. We show that the slave rotor and $ s$ -boson have the same algebraic structure, and we establish a unified functional integral framework connecting the $ s$ -boson and slave rotor representations for the single impurity Anderson model.
Strongly Correlated Electrons (cond-mat.str-el)
11 + 6 pages, 7 figures
Polarization-dependent chiral transport and chiral solitons in spin Kitaev models
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-26 20:00 EDT
Chenwei Lv, Thomas Bilitewski, Ana Maria Rey, Qi Zhou
Recent advances in synthetic quantum matter allow researchers to design quantum models inaccessible in traditional materials. Here, we propose protocols to engineer a new class of quantum spin models, which we call spin Kitaev models. The building blocks are basic spin-exchange interactions combined with locally selective Floquet pulses, a capability recently demonstrated in a range of experimental platforms. The resulting flip-flip and flop-flop terms lead to intriguing quantum transport dynamics beyond conventional spin models. For instance, in the absence of a magnetic field, spin excitations polarized along the $ x$ and $ y$ axes propagate chirally in opposite directions, producing polarization-dependent spin transport. In the large-spin limit, the spin Kitaev model maps to a nonlinear Hatano-Nelson model, where the interplay of nonlinearity and the underlying curvature yields polarization-dependent chiral solitons. A magnetic field binds two oppositely polarized chiral solitons into a chiral solitonic molecule, whose travel direction depends on its orientation. Our results, directly accessible in current experiments, open new opportunities for simulating transport in curved spaces and for applications in spintronics, information processing, and quantum sensing.
Quantum Gases (cond-mat.quant-gas), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Pattern Formation and Solitons (nlin.PS), Quantum Physics (quant-ph)
7+9 pages, 3+7 figures
Segregation-driven cross-slip mechanism of shockley partials in the gamma prime phase of CoNi-based superalloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Zhida Liang, Fengxian Liu, Xin Liu, Yang Li, Yinan Cui, Florian Pyczak
In general, the cross-slip of superdislocations (a/2<011>) from {111} planes to {001} planes has been frequently observed in superalloys, accompanied by the formation of an antiphase boundary (APB) and driven by thermal activation. However, no prior studies have evidenced the occurrence of Shockley partial dislocation (a/6<112>) cross-slip within the gamma prime phase of superalloys. In this work, we present a newly observed cross-slip phenomenon: the Shockley partial dislocations cross-slip from one {111} plane to another {111} conjugate plane, facilitated by the formation of a stair-rod dislocation in the ordered gamma prime phase of a CoNi-based superalloy. Compression tests were conducted at 850 degrees Celsius with a strain rate of 10^-4 s^-1. Defects such as stacking faults and dislocations, along with the associated chemical fluctuations, were characterized using high-resolution scanning transmission electron microscopy (HRSTEM) and energy-dispersive X-ray spectroscopy (EDS). Elemental segregation was found to reduce the activation energy required for cross-slip by decreasing the energies of stacking faults and dislocations. In addition to elemental segregation, local stress concentrations, arising from the combined effects of applied stress, shearing dislocations within the gamma prime phase, and dislocation pile-ups, also play a critical role in triggering cross-slip. The formation of sessile stair-rod dislocations via this newly identified Shockley partial cross-slip in the gamma prime phase is beneficial for enhancing the high-temperature deformation resistance of the alloy by increasing the critical resolved shear stress required for further plastic deformation.
Materials Science (cond-mat.mtrl-sci)
Molecular augmented dynamics: Generating experimentally consistent atomistic structures by design
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Tigany Zarrouk, Miguel A. Caro
A fundamental objective of materials modeling is identifying atomic structures that align with experimental observables. Conventional approaches for disordered materials involve sampling from thermodynamic ensembles and hoping for an experimental match. This process is inefficient and offers no guarantee of success. We present a method based on modified molecular dynamics, that we call molecular augmented dynamics (MAD), which identifies structures that simultaneously match multiple experimental observables and exhibit low energies as described by a machine learning interatomic potential (MLP) trained from ab-initio data. We demonstrate its feasibility by finding representative structures of glassy carbon, nanoporous carbon, ta-C, a-C:D and a-CO$ _x$ that match their respective experimental observables – X-ray diffraction, neutron diffraction, pair distribution function and X-ray photoelectron spectroscopy data – using the same initial structure and underlying MLP. The method is general, accepting any experimental observable whose simulated counterpart can be cast as a function of differentiable atomic descriptors. This method enables a computational “microscope” into experimental structures.
Materials Science (cond-mat.mtrl-sci)
Liquid-liquid phase separation enables highly selective viral genome packaging
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Layne B. Frechette, Michael F. Hagan
In many viruses, hundreds of proteins assemble an outer shell (capsid) around the viral nucleic acid to form an infectious virion. How the assembly process selects the viral genome amidst a vast excess of diverse cellular nucleic acids is poorly understood. It has recently been discovered that many viruses perform assembly and genome packaging within liquid-liquid phase separated biomolecular condensates inside the host cell. However, the role of condensates in genome packaging is poorly understood. Here, we construct equilibrium and dynamical rate equation models for condensate-coupled assembly and genome packaging. We show that when the viral genome and capsid proteins favorably partition into the condensate, assembly rates, yields, and packaging efficiencies can increase by orders of magnitude. Selectivity is further enhanced by the condensate when capsid proteins are translated during assembly and packaging. Our results suggest that viral condensates provide a mechanism to ensure robust and highly selective assembly of virions around viral genomes. More broadly, our results may apply to other types of selective co-assembly processes that occur within biomolecular condensates, and suggest that liquid-liquid phase-separated condensates could be exploited for selective encapsulation of microscopic cargo in human-engineered systems.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
Main Text: 19 pages, 5 figures; Supplemental Material: 16 pages, 7 figures
Resonant transport and line-type resonances in tilted Dirac cone double-barrier structures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
M. Raggui, O. Habti, A. Kamal, E.B. Choubabi
We study the transport properties of Dirac fermions in a graphene-based double-barrier structure composed of two tilted-cone regions separated by a central pristine graphene region. Using the transfer matrix method, we systematically analyze how different cone tilts affect Dirac fermion transmission. In reciprocal space, at fixed energy, the Dirac cones of distinct regions generate isoenergetic conical surfaces (Fermi surfaces). When these surfaces overlap, their intersections define ``active surfaces’’ that enable fermion transmission. In the symmetric double-barrier configuration, coupling between the barriers and the central well gives rise to multiple resonance peaks, including line-type resonances, even within nominally forbidden energy zones. The number and positions of these resonances depend sensitively on the system parameters. These findings provide new insights into the role of Dirac cone tilt in complex junctions and may guide the design of nanoelectronic devices based on two-dimensional tilted-cone materials such as $ \alpha$ -(BEDT-TTF)$ _2$ I$ _3$ and borophene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Tunable Valley Polarization and Anomalous Hall Effect in Ferrovalley NbX2 and TaX2 (X = S, Se, Te): A First-Principles Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Samiul Islam, Sharif Mohammad Mominuzzaman, Ahmed Zubair
Two-dimensional transition metal dichalcogenides lack inversion symmetry and have broken time-reversal symmetry due to the honeycomb structure and intrinsic ferromagnetism, which leads to their valley polarization. Here, we explored the electronic and magnetic properties of the novel ferrovalley materials 1H-NbS2, 1H-NbSe2, 1H-NbTe2, 1H-TaS2, 1H-TaSe2, and 1H-TaTe2 using first-principles calculations based on density functional theory. The materials are dynamically stable bipolar magnetic semiconductors. Among the magnetic semiconductors, NbSe2 showed the maximum Curie temperature of 176.25 K. For these materials, the ferromagnetic state was more favorable than the antiferromagnetic state, indicating robust ferrovalley characteristics. These ferrovalley materials showed a giant tunable valley polarization at K and K’ points in the Brillouin zone without applying any external factors due to intrinsic exchange interactions of transition metal d-orbital electrons and spin-orbit coupling. TaTe2 exhibited an outstanding valley splitting of 541 meV. Reversing Bloch electrons’ magnetic moment caused an alteration of valley polarization. Additionally, the application of uniaxial and biaxial strain led to the manipulation and variation of the bandgap and valley polarization. Berry curvature exhibited opposite signs and unequal magnitudes at K and K’ points, which led to the anomalous valley Hall effect in these materials. NbS2, NbSe2, and NbTe2 exhibited Berry curvature at unstrained crystals, whereas Berry curvature appeared only in TaSe2 and TaTe2 with the application of strain. These ferrovalley materials exhibited distinct band gaps for spin-up and spin-down electrons, enabling the selective transport of spin-polarized electrons.
Materials Science (cond-mat.mtrl-sci)
Functional theory of the occupied spectral density
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Andrea Ferretti, Nicola Marzari
We address the problem of interacting electrons in an external potential by introducing the occupied spectral density $ \rho(\mathbf{r},\omega)$ as fundamental variable. First, we formulate the problem using an embedding framework, and prove a one-to-one correspondence between a $ \rho(\mathbf{r},\omega)$ and the local dynamical external potential $ v_{\text{ext}}(\mathbf{r},\omega)$ that embeds the interacting electrons into an open quantum system. Then, we use the Klein functional to ($ i$ ) define a universal functional of $ \rho(\mathbf{r},\omega)$ , ($ ii$ ) introduce a variational principle for the total energy as a functional of $ \rho(\mathbf{r},\omega)$ , and ($ iii$ ) formulate a non-interacting mapping of spectral self-consistent equations suitable for numerical applications. At variance with time-dependent density-functional theory, this formulation aims at studying charged excitations and electronic spectra – including electronic correlations – with a functional theory; An explicit and formally correct description of all electronic levels could also lead to more accurate approximations for the total energy.
Materials Science (cond-mat.mtrl-sci)
Metal-Free Room-Temperature Ferromagnetism
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Achieving robust room-temperature ferromagnetism in purely organic 2D crystals remains a fundamental challenge, primarily due to antiferromagnetic (AFM) coupling mediated by {\pi}-electron superexchange. Here, we present a mix-topology design strategy to induce strong ferromagnetic (FM) coupling in metal-free 2D systems. By covalently connecting radical polyaromatic hydrocarbon monomers (also referred to as nanographenes) with distinct sublattice topologies, this approach rationally breaks inversion symmetry and enables selective alignment of majority spins across the extended network, giving rise to metal-free ferromagnetism. Based on this strategy, we designed a family of 32 organic 2D crystals featuring spin-1/2 and mixed spin-1/2-spin-1 honeycomb lattices. Systematic first-principles calculations reveal that these materials are robust FM semiconductors with tunable spin-dependent bandgaps ranging from 0.9 to 3.8 eV. Notably, we demonstrate record-high magnetic coupling of up to 127 meV, spin-splitting energies exceeding 2 eV, and Curie temperatures surpassing 550 K, indicating thermal stability well above room temperature. The microscopic origin of the strong FM exchange stems from enhanced spin-orbital overlap and dominant direct exchange, while AFM superexchange is effectively suppressed. Our findings establish a generalizable design principle for realizing robust metal-free FM semiconductors and open new avenues for developing flexible and biocompatible magnets for next-generation spintronic and quantum technologies.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Correlations in the Binding Energy of Triexcitons and Biexcitons in Single CdSe/CdS Nanoplatelets Revealed by Heralded Spectroscopy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Daniel Amgar, Nadav Frenkel, Dekel Nakar, Dan Oron
Semiconductor nanoplatelets present reduced Auger recombination, giving rise to enhanced multiexciton emission. This virtue makes them good candidates to investigate higher-order carrier dynamics, allowing to extract important excitonic properties, such as biexciton and triexciton binding energies that highly influence applications involving high excitation fluxes. Here, we explore triexciton emission, emanating from single core/shell CdSe/CdS nanoplatelets. We apply heralded post-selection of photon triplets using an advanced home-built single-photon spectrometer in order to resolve the triexciton$ -$ biexciton$ -$ exciton$ -$ ground state cascaded relaxation both in time and spectrum, and unambiguously determine the triexciton relaxation route and interaction nature. The results show a characteristic blue shift of the biexciton and triexciton, pointing to repulsive multiexciton interaction in the nanoplatelets under study. The relatively small measured energy shift of the triexciton (5.9 $ \pm$ 0.7 meV) indicates that it recombines through the 1S bands rather than the 1P bands, in agreement with findings on other colloidal quantum dot systems. Most importantly, the strong correlation between the biexciton and triexciton binding energies, and the ability to tune them via control of the particle dimensions and composition, paves the way for developing emitters of nearly degenerate photon triplets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics), Quantum Physics (quant-ph)
33 pages, 13 figures
Phonons Drive the Topological Phase Transition in Quasi-One-Dimensional Bi$_4$I$_4$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Wenjie Hu, Jiayi Gong, Yuhui Qiu, Lexian Yang, Jin-Jian Zhou, Yugui Yao
Quasi-one-dimensional bismuth halides offer an exceptional platform for exploring diverse topological phases, yet the nature of the room-temperature topological phase transition in Bi$ _4$ I$ _4$ remains unresolved. While theory predicts the high-temperature $ \beta$ -phase to be a strong topological insulator (TI), experiments observe a weak TI. Here we resolve this discrepancy by revealing the critical but previously overlooked role of electron-phonon coupling in driving the topological phase transition. Using our newly developed ab initio framework for phonon-induced band renormalization, we show that thermal phonons alone drive $ \beta$ -Bi$ _4$ I$ _4$ from the strong TI predicted by static-lattice calculations to a weak TI above ~180 K. At temperatures where $ \beta$ -Bi$ _4$ I$ _4$ is stable, it is a weak TI with calculated surface states closely match experimental results, thereby reconciling theory with experiment. Our work establishes electron-phonon renormalization as essential for determining topological phases and provides a broadly applicable approach for predicting topological materials at finite temperatures.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Spectral Functions of an Extended Antiferromagnetic $S=1/2$ Heisenberg Model on the Triangular Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Markus Drescher, Laurens Vanderstraeten, Roderich Moessner, Frank Pollmann
We study an extended spin-$ 1/2$ antiferromagnetic Heisenberg model on the triangular lattice, which includes both nearest- and next-nearest-neighbor interactions, as well as a scalar chiral term. This model exhibits a rich phase diagram featuring several competing phases: different quantum spin liquids and various magnetically ordered states, including coplanar $ 120^\circ$ order, stripe order, and non-coplanar tetrahedral order. We employ large-scale matrix product state simulations optimized for GPUs to obtain high-resolution dynamical responses. Our calculations reveal the spectral features across both ordered and liquid regimes of the phase diagram, which we analyze in comparison with analytical predictions and field-theoretical approaches. We identify unique signatures of the ordered phases in the form of gapless Goldstone modes at the ordering wave vectors. Our results in the $ J_1-J_2$ quantum spin-liquid regime are indicative of a $ U(1)$ Dirac spin liquid. In the chiral spin-liquid phase, we find signatures of spinons as the fractional excitations of the underlying theory, manifested as the onset of a two-spinon continuum that agrees with predictions from the Kalmeyer-Laughlin ansatz for the ground-state wave function, and collective modes that can be viewed as spinon bound states. We discuss finite-size effects, their consistency with the presumptions from field-theory, and review the dynamical structure factor with regard to experimentally relevant features such as the occurrence of highly dispersive signals and the global distribution of spectral weight.
Strongly Correlated Electrons (cond-mat.str-el)
16 + 18 pages, 7 + 28 figures
Cooperative Suppression Strategy for Dual Thermal Transport Channels in Crystalline Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Yu Wu, Ying Chen, Shuming Zeng, Hao Zhang, Liujiang Zhou, Chenhan Liu, Su-Huai Wei
We propose a novel design principle for achieving ultralow thermal conductivity in crystalline materials via a “heavy-light and soft-stiff” structural motif. By combining heavy and light atomic species with soft and stiff bonding networks, both particle-like ($ \kappa_p$ ) and wave-like ($ \kappa_c$ ) phonon transport channels are concurrently suppressed. First-principles calculations show that this architecture induces a hierarchical phonon spectrum: soft-bonded heavy atoms generate dense low-frequency modes that enhance scattering and reduce $ \kappa_p$ , while stiff-bonded light atoms produce sparse high-frequency optical branches that disrupt coherence and lower $ \kappa_c$ . High-throughput screening identifies Tl$ _4$ SiS$ _4$ ($ \kappa_p$ = 0.10, $ \kappa_c$ = 0.06 W/mK) and Tl$ _4$ GeS$ _4$ ($ \kappa_p$ = 0.09, $ \kappa_c$ = 0.06 W/mK) as representative candidates with strongly suppressed transport in both channels. A minimal 1D triatomic chain model further demonstrates the generality of this mechanism, offering a new paradigm for phonon engineering beyond the conventional $ \kappa_p$ -$ \kappa_c$ trade-off.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Orbital-selective two-gap superconductivity in kagome metal CsV3Sb5
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Run Lv, Wenqian Tu, Dingfu Shao, Yuping Sun, Wenjian Lu
Recent experiments have revealed anisotropic multigap superconductivity in the kagome metal CsV3Sb5. However, the interplay between its multi-orbital character and electron-phonon coupling (EPC) in governing multiple superconducting gaps remains incompletely understood. In this work, we theoretically investigate the superconducting gap of CsV3Sb5 by combining first-principles calculations with superconducting density functional theory (SCDFT). Our results demonstrate that orbital-selective pairing drives the observed two-gap superconductivity in CsV3Sb5. Specifically, the two distinct gaps exhibit strong orbital dependence: a large, highly anisotropic gap (average magnitude 0.64 meV) primarily originates from V-3d orbitals, while a small, isotropic gap (0.25 meV) is associated with the Sb-5pz orbital. The V-3d orbitals strongly couple to the in-plane V-V bond-stretching and out-of-plane V-Sb bending phonon modes, whereas the kagome-plane Sb-5pz orbital weakly interacts with Cs shearing phonon mode. Moreover, our calculations reveal EPC-induced band renormalization, manifested as kinks at approximately -13 meV and -30 meV in the electronic dispersion, consistent with prior experimental observations. These findings provide fundamental insights into the orbital-selective superconductivity and EPC mechanisms in kagome CsV3Sb5.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Strong Enhancement of Spin-Orbit Torques and Perpendicular Magnetic Anisotropy in [Pt0.75Ti0.25/Co-Ni multilayer/Ta]n Superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Xiaomiao Yin, Zhengxiao Li, Jun Kang, Changmin Xiong, Lijun Zhu
We report the development of the [Pt0.75Ti0.25/Co-Ni multilayer/Ta]n superlattice with strong spin-orbit torque, large perpendicular magnetic anisotropy, and low switching current density. We demonstrate that the efficiency of the spin-orbit torque increases linearly with the repetition number n, which is in good agreement with the spin Hall effect of the Pt0.75Ti0.25 being the only source of the spin-orbit torque. Meanwhile, the perpendicular magnetic anisotropy field is also enhanced by more than a factor of 2 as n increases from 1 to 6. The [Pt0.75Ti0.25/(Co/Ni)3/Ta]n superlattice also exhibits deterministic, low-current-density magnetization switching despite the very large layer thicknesses. The combination of the strong spin-orbit torque, perpendicular magnetic anisotropy, and low-current-density switching makes the [Pt0.75Ti0.25/Co-Ni multilayer/Ta]n superlattice a compelling material candidate for ultrafast, energy-efficient, long-data-retention spintronic technologies.
Materials Science (cond-mat.mtrl-sci)
Robust Mottness and tunable interlayer magnetism in Nb3X8 (X = F, Cl, Br, I) bilayers
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Zhongqin Zhang, Jiaqi Dai, Cong Wang, Zhihai Cheng, Wei Ji
Kagome materials have attracted extensive attention due to their correlated properties. The breathing kagome material system Nb3X8 (X = F, Cl, Br, I) is regarded as a Mott insulator. However, studies on the influence of interlayer coupling on its magnetic and Mott properties are lacking. In this work, we investigated the effect of interlayer coupling on bilayer properties of each Nb3X8 (X = F, Cl, Br, I) compound via density functional theory (DFT) calculations, considering 24 stacking configurations per material. We found that each bilayer material is a Mott insulator. Due to the competition between interlayer Pauli repulsion and hopping, most interlayer magnetism is AFM, a small number of cases show AFM-FM degeneracy, and the magnetic ground state of 3 configurations is interlayer FM, i.e., tunable interlayer magnetism occurs. This robustness of Mott states coexisting with tunable interlayer magnetism provide novel and comprehensive analysis and insights for the research of breathing kagome Mott insulators.
Strongly Correlated Electrons (cond-mat.str-el)
Revisiting the adiabatic limit in ballistic multiterminal Josephson junctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Régis Mélin, Asmaul Smitha Rashid, Romain Danneau, Morteza Kayyalha
Motivated by recent experiments on multiterminal Josephson junctions (MJJs) that probe different ranges of the size and bias voltage parameters, we introduce a two-dimensional (2D) cross-over diagram to map the relationship between device dimension (x-axis) and bias voltage (y-axis). This cross-over diagram conveniently separates the different physical regimes of the devices. This framework is used to explore the regime of increasing bias voltage in large-scale devices near the x-axis, where the electrochemical potential becomes comparable to the 1D energy level spacing. In a perfect waveguide geometry, we find that the relative number of quantum-correlated pairs formed by colliding Floquet-Kulik levels is equal to the inverse of the number of transverse channels, due to the number of conserved quantities equal to the number of channels. This observation motivates a model for the intermediate regime in which the ballistic central two-dimensional normal metal is treated as a continuum under the adiabatic approximation, while Andreev modes propagate in a background of voltage- and flux-tunable nonequilibrium electronic populations. The model predicts characteristic voltage scales that govern the mesoscopic oscillations of the critical current, and these scales are at the crossroads of interpreting experiments in all sectors of the MJJs: quartets, topology, and Floquet theory.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
16 pages, 10 figures
Dynamics and transport of Bose-Einstein condensates in bent potentials
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-26 20:00 EDT
The dynamics of bosons in curved geometries have recently attracted significant interest in quantum many-body physics. Leveraging recent experimental advances in tailored trapping landscapes, we investigate the quantum transport of weakly interacting bosons in two-dimensional bent trapping potentials, showing that geometry alone can serve as a precise control knob for tunneling dynamics. Using time-adaptive many-body simulations, complemented by mean-field analysis and exact diagonalization, we analyze both static and dynamical properties of bosons confined in the bent potential. We reveal how bending an initially straight channel induces a transition from density localization to delocalization and drives the buildup of correlations in the ground state. In the dynamics, the bent acts as a tunable barrier that enables controllable tunneling: weak curvature allows coherent tunnelling across the bend, while stronger bent suppresses transport and enhances self-trapping. The tunneling rate can be precisely tuned by geometric parameters, establishing bent traps as versatile platforms for geometry-controlled quantum transport.
Quantum Gases (cond-mat.quant-gas)
25 pages, 7 figures
Spontaneous Lattice Distortion in the Spin-Triplet Superconductor Cu$_{x}$Bi$_2$Se$_3$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
K. Matano, S. Takayanagi, K. Ito, S. Nita, M. Yokoyama, M. Mihaescu, H. Nakao, Guo-qing Zheng
The doped topological insulator Cu$ _x$ Bi$ _2$ Se$ _3$ has attracted considerable attention as a new platform for studying novel properties of spin-triplet and topological superconductivity. In this work, we performed synchrotron x-ray diffraction measurements on Cu$ _x$ Bi$ _2$ Se$ _3$ (0.24$ \leq x\leq$ 0.46) to investigate the coupling between the superconducting order parameter and crystal lattice. In the crystals in which the vector order parameter ($ {\boldsymbol d}$ vector) is tilted from the crystal high-symmetry directions as evidenced by nematic diamagnetic susceptibility, we find a sizable lattice distortion ($ \sim$ 100 ppm) associated with the onset of superconductivity. In contrast, in crystals with the $ {\boldsymbol d}$ vector aligned along the high-symmetry directions, we find no appreciable change in lattice constant. Together with a pronounced vestigial behavior of the distortion, the results are clear evidence for an odd-parity $ E_u$ order parameter that couples with trigonal lattice. Furthermore, in the crystal with $ x$ = 0.46 where diamagnetic susceptibility is isotropic in the plane, no lattice distortion accompanying the superconducting transition is found, which is in line with a chiral superconducting state in the highly doped region. Our work shows that lattice distortion can be a powerful diagnosing quantity for nematic superconductivity with two-component order parameter.
Superconductivity (cond-mat.supr-con)
13 pages, 5 figures
Phys. Rev. Lett. 135, 086001 (2025)
Ambient-Pressure Superconductivity from Boron Icosahedral Superatoms
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Simone Di Cataldo, Antonio Sanna, Lilia Boeri
We identify a new family of XB$ _{12}$ , boron-rich compounds formed by interconnected B$ _{12}$ icosahedra and electropositive guest atoms ($ X$ ). These structures emerged from first-principles crystal structure prediction at 50 GPa, as part of a pressure-quenching strategy to discover superconductors that could be synthesized under pressure and retained at ambient conditions. The resulting structures are thermodynamically competitive, dynamically stable at zero pressure, and - when $ X$ is a mono- or trivalent element - metallic and superconducting. Predicted critical temperatures reach up to 42 K for CsB$ _{12}$ , rivaling MgB$ _2$ , the highest-$ T_c$ ambient-pressure conventional superconductor.
We interpret the XB$ _{12}$ phase as a superatomic crystal: the B$ _{12}$ units retain their molecular identity while forming extended crystalline networks. Their delocalized orbitals support doping without structural destabilization, while their covalent bonding promotes strong electron-phonon coupling. Unlike MgB$ _2$ , where superconductivity is driven by a narrow subset of phonon modes, the XB$ _{12}$ compounds exhibit broad, mode- and momentum-distributed coupling through both intra- and inter-superatomic vibrations. Our results highlight the XB$ _{12}$ family as a promising platform for metastable superconductivity and demonstrate the potential of superatoms as functional building blocks in solid-state materials design.
Superconductivity (cond-mat.supr-con), Chemical Physics (physics.chem-ph)
9 pages, 7 figures
Out-of-plane angle resolved second harmonic Hall analysis in perpendicular magnetic anisotropy systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Akanksha Chouhan, Abhishek Erram, Ashwin A. Tulapurkar
Second Harmonic Hall (SHH) measurement is a standard and well accepted technique to estimate spin orbit torque (SOT) efficiencies in perpendicular magnetic anisotropy (PMA) systems. Generally, field sweep and in-plane angle sweep SHH measurements are performed and SOT efficiency calculation is done using effective fields based formalism. In this article, we demonstrate an alternate experimental approach of out-of-plane (OOP) angle resolved SHH measurement in PMA systems for SOT efficiencies estimation. Also, we present an alternate formalism for SOT efficiency extraction, derived by solving LLGS equation in the low frequency limit of magnetic susceptibility. Along with SHH measurements, we also experimentally demonstrate anomalous Hall effect (AHE) based spin-torque ferromagnetic resonance (STFMR) for PMA systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Pulsed laser synthesis of mesoporous metal chalcogenide thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Dorien E. Carpenter, Zahra Nasiri, Nithesh R. Palagiri, Kamron L. Strickland, Sumner B. Harris, David B. Geohegan, Renato P. Camata
Mesoporous films of the metal chalcogenide $ \beta$ -FeSe were grown on MgO substrates by KrF pulsed laser deposition (PLD) in an argon background. At 100 mTorr, gated intensified charge-coupled device imaging and ion probe measurements showed that the plasma plume responsible for crystal growth initially comprised three components, with distinct expansion velocities. Plume interactions with the substrate heater and ablation target gave rise to complex dynamics, including collisions between the charged leading edge – rebounding between the substrate and the target – and slower-moving species in the plume interior. Film growth was dominated by species with kinetic energies $ \le$ 0.5 eV/atom. X-ray reflectivity and atomic force microscopy revealed that films grown in this environment – with a substrate temperature of 350$ ^\circ$ C, a laser fluence of 1.0 J cm$ ^{-2}$ , and a 7.5 mm$ ^2$ spot area – formed a porous framework with 15% porosity and pore sizes below 100 nm. X-ray diffraction indicated that the porous films were epitaxial with respect to the substrate and likely grew by oriented-attachment of gas-phase molecular clusters or very small nanoparticles, in contrast to the conventional epitaxy of vacuum films from atomic constituents. The in-plane orientation of the mesoporous films was $ \beta$ -FeSe[100]$ \parallel$ [110]MgO, attributed to the soft landing of pre-formed crystallites on the MgO substrates, where protruding Se rows of $ \beta$ -FeSe aligned with corrugations of the MgO surface. This work implies that growth of candidate electrocatalyst materials by PLD in inert gas background may allow mesoporous frameworks with a single crystallographic orientation that expose specific crystal facets for electrochemical reactions and active site engineering.
Materials Science (cond-mat.mtrl-sci), Plasma Physics (physics.plasm-ph)
Spin-Orbit Driven Topological Phases in Kagome Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Kagome materials have garnered substantial attention owing to their diverse physical phenomena, yet canonical systems such as the AV$ _3$ Sb$ 5$ family exhibit poor $ Z{2}$ -type topological properties, spurring an urgent quest for kagome platforms hosting ideal topological states. Recently, Zhou et al. proposed the kagome-type IAMX family, which exhibits distinctive ideal topological states; however, their analysis is primarily restricted to the spinless approximation. In this work, we model relativistic effects in the IAMX family, demonstrating that tuning the spin-orbit coupling (SOC) strength drives topological phase transitions and induces novel topological states, resulting in a rich phase diagram. The configuration of topological surface states evolves continuously as the SOC strength is modulated, consistent with the evolution of the topological phase transition. This suggests a viable route toward designing multi-functional topological devices. First-principles calculations performed on three specific IAMX compounds confirm that SOC governs their topological phases, in complete accord with our model analysis.
Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Topological phase transitions between bosonic and fermionic quantum Hall states near even-denominator filling factors
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Evgenii Zheltonozhskii, Ady Stern, Netanel H. Lindner
We study the quantum critical point between the fermionic $ \nu=8$ quantum Hall state and the bosonic $ \nu=2$ quantum Hall state of Cooper pairs. Our study is motivated by the composite fermion construction for the daughter states of even-denominator fractional quantum Hall states and the experimentally observed transition between the daughter and the Jain states at the same filling. We show that this transition is equivalent to the transition between a neutral invertible $ E_8$ state and a topologically trivial state. These transitions can be described in a partonic framework as a cascade of mass changes of four neutral Dirac fermions coupled to multiple Abelian Chern-Simons $ U(1)$ gauge fields. In the absence of fine-tuning, the transition is split into a series of four or more different transitions, with at least three distinct intermediate topologically ordered phases hosting neutral anyons.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
High-Throughput Screening of 2D Photocatalyst Heterostructures with Suppressed Electron-Hole Recombination for Solar Water Splitting
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Shivanand Yadav, Jainandan Kumar Modi, Raihan Ahammed, B. S. Bhadoria, Yogesh S. Chauhan, Amit Agarwal, Somnath Bhowmick
Efficient and scalable photocatalysts for solar water splitting remain a critical challenge in renewable energy research. The work presents a high-throughput first-principles discovery of two-dimensional (2D) type-II van der Waals heterostructures (vdWHs) optimized for visible-light-driven photocatalytic water splitting. We screened 482 heterostructures constructed from 60 experimentally realizable 2D monolayers and identified 148 stable type-II vdWHs with spatially separated valence and conduction band edges, out of which 65 satisfy the thermodynamic redox conditions for water splitting over a broad pH range. Among these, the best two, MoTe2/Tl2O and MoSe2/WSe2, exhibit a high visible-light absorption coefficient exceeding 0.6X10^6 cm-1, resulting in a high power conversion efficiency of 2%. Quantum kinetic analysis of the hydrogen evolution reaction (HER) reveals nearly barrierless free energy profiles across multiple adsorption sites. Our study further reveals that intrinsic interlayer electric fields in these vdWHs drive directional charge separation, suppressing carrier recombination. Our results establish a design framework for using type-II 2D heterostructures as tunable and experimentally accessible 2D photocatalysts for efficient hydrogen production.
Materials Science (cond-mat.mtrl-sci)
22 pages, 5 figures
Mechanisms of superconductivity and inhomogeneous states in metallic hydrogen and electron systems with attraction
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
M. Yu. Kagan, A.V. Krasavin, R.Sh. Ikhsanov, E.A. Mazur, A.P. Menushenkov
In the Review we discuss anomalous aspects of superconductivity (SC) and normal state, as well as formation of inhomogeneous (droplet-like or cluster-like) states in electron systems with attraction. We consider both the models with the retardation (Eliashberg mechanism of SC for strong electron-phonon interaction in metallic hydrogen) and without retardation (but with local onsite attraction). We concentrate on the mechanism of the BCS-BEC crossover for the Hubbard model with local attraction and diagonal disorder for the two-dimensional films of the dirty metal. We analyze also the model of the inhomogeneous spaceseparated Fermi-Bose mixture for the bismuth oxides BaKBiO, which contains the paired clusters of bosonic states as well as unpaired fermionic clusters. Superconductivity is realized in this system due to local pairs tunneling from one bosonic cluster to the neighboring one via the fermionic barrier. For metallic hydrogen and metallic hydrides, we calculate the critical temperature and discuss important possibility for practical applications how to increase the temperature by decreasing pressure in the framework of the generalized Eliashberg approach. We advocate also interesting analogies with the quantum (vortex) crystal for long-living low-dimensional metastable phases of metallic hydrogen including filamentous phase with proton chains embedded in 3D electron Fermi liquid and planar phase with proton plains. We formulate the concept of two Bose-condensates in SC electron and superfluid (SF) ion subsystems and provide the estimate for the lifetime of the long-living metastable phases at normal pressure. The estimate is connected with the formation and growth of the critical seeds of the new (molecular) phase in the process of quantum under-barrier tunneling.
Superconductivity (cond-mat.supr-con)
14 pages, 6 figures
Scalable implementations of mean-field and correlation methods based on Lie-algebraic similarity transformation of spin Hamiltonians in the Jordan-Wigner representation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Shadan Ghassemi Tabrizi, Thomas M. Henderson, Thomas D. Kühne, Gustavo E. Scuseria
Recent work has highlighted that the strong correlation inherent in spin Hamiltonians can be effectively reduced by mapping spins to fermions via the Jordan-Wigner transformation (JW). The Hartree-Fock method is straightforward in the fermionic domain and may provide a reasonable approximation to the ground state. Correlation with respect to the fermionic mean-field can be recovered based on Lie-algebraic similarity transformation (LAST) with two-body correlators. Specifically, a unitary LAST variant eliminates the dependence on site ordering, while a non-unitary LAST yields size-extensive correlation energies. Whereas the first recent demonstration of such methods was restricted to small spin systems, we present efficient implementations using analytical gradients for the optimization with respect to the mean-field reference and the LAST parameters, thereby enabling the treatment of larger clusters, including systems with local spins s > 1/2.
Strongly Correlated Electrons (cond-mat.str-el)
37 pages, 11 figures
Learning Reaction-Diffusion Kinetics from Mechanical Information
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Royal C. Ihuaenyi, Hongbo Zhao, Ruqing Fang, Ruobing Bai, Martin Z. Bazant, Juner Zhu
A central challenge in materials science is characterizing chemical processes that are elusive to direct measurement, particularly in functional materials operating under realistic conditions. Here, we demonstrate that mechanical strain fields contain sufficient information to reconstruct hidden chemical kinetics in coupled chemomechanical systems. Our partial differential equation-constrained learning framework decodes concentration-dependent diffusion kinetics, thermodynamic driving forces, and spatially heterogeneous reaction rates solely from mechanical observations. Using battery electrode materials as a model system, we demonstrate that the framework can accurately identify complex constitutive laws governing three distinct scenarios: classical Fickian diffusion, spinodal decomposition with pattern formation, and heterogeneous electrochemical reactions with spatial rate variations. The approach demonstrates robustness while maintaining accuracy with limited spatial data and reasonable experimental noise levels. Most significantly, the framework simultaneously infers multiple fundamental processes and properties, including diffusivity, reaction kinetics, chemical potential, and spatial heterogeneity maps, all from mechanical information alone. This method establishes a paradigm for materials characterization, enabling accurate learning of chemical processes in energy storage systems, catalysts, and phase-change materials where conventional diagnostics prove difficult. By revealing that mechanical deformation patterns serve as information-rich fingerprints of the underlying chemical processes, this work follows the pathway of inversely learning constitutive laws, with broad implications in materials science and engineering.
Materials Science (cond-mat.mtrl-sci)
Superconducting NbN Resonator Parametric Amplifiers for Millimetre Wavelengths
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Songyuan Zhao, Stafford Withington, Christopher Thomas
We report the development of a reactive sputtering process for high $ T_\mathrm{c}$ NbN films with high normal-state resistivity, tailored for kinetic inductance parametric amplifiers. The process includes precise control to ensure full nitridation of the target prior to deposition. Under optimized conditions, the resulting NbN thin films exhibit a critical temperature of $ 10.5,\mathrm{K}$ and a resistivity of $ \sim1000,\mathrm{\mu\Omega,cm}$ . The high $ T_\mathrm{c}$ of the NbN thin-films suggests strong potential for application over the entire millimetre-wave frequency range from $ 24,\mathrm{GHz}$ to $ 300,\mathrm{GHz}$ , whereas the high resistivity suggests a reduced power requirement for the pump tone to achieve high gain. Resonator parametric amplifiers have been fabricated from these films using coplanar waveguide geometry. The devices were able to produce high gain exceeding $ 20,\mathrm{dB}$ at $ 25,\mathrm{GHz}$ , with artefact-free, reproducible amplification profiles in good agreement with theoretical models.
Superconductivity (cond-mat.supr-con), Instrumentation and Methods for Astrophysics (astro-ph.IM)
Universal scaling of higher-order cumulants in quantum isotropic spin chains
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-26 20:00 EDT
Shixian Jiang, Jianpeng Liu, Jianmin Yuan, Xi-Wen Guan, Yongqiang Li
Understanding universal behavior of far-from-equilibrium transport dynamics at a quantum many body level is a longstanding challenge. In particular, a full characterization of universal dynamics of nonlocal correlation functions still remains largely unknown. In this letter, we uncover universal scaling laws of higher-order cumulants in one-dimensional isotropic Heisenberg model, revealing anomalous behaviors of nonequilibrium dynamics exclusively accessible in higher-order correlations. By means of numerical simulations and full counting statistics, we determine the power laws of both the spin polarization transfer and contrast cumulants for different kinds of helix and domain-wall initial states. Building on such physical states, we unify the scaling behavior of the higher-order cumulants, giving rise to two types of dynamics: anomalous diffusive and superdiffusive. For the former, these higher cumulants show a deviation from Gaussian statistics, with the scaling exponents being identical for the first four orders. For the latter, however, we observe a breakdown of KPZ universality, with the exponents of the third and fourth orders differing significantly from those of the first two. Our results are also agreeable with recent experimental observations, advancing understanding of far-from-equilibrium transport phenomena.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Neo-Gibbsian Statistical Energetics with Applications to Nonequilibrium Cells
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-26 20:00 EDT
Bing Miao, Hong Qian, Yong-Shi Wu
Generalization through novel interpretations of the inner logic of the century-old Gibbs’ statistical thermodynamics is presented: i) Identifying $ k_B\to 0$ as classical energetics, one directly derives a pair of thermodynamic variational formulae [
F(T) = \min_{E\ge E_{min}}\Big{E-TS(E) \Big}
,\text{ and }
S(E) = \min_{T>0}\left{\frac{E}{T}-\frac{F(T)}{T} \right}, ] that dictate all the more familiar $ 1/T=d S(E)/d E$ , $ E=d{F(T)/T}/d(1/T)$ , and $ S(E)=-d F(T)/d T$ in equilibrium, which is maintained by a duality symmetry with one-to-one relation between $ T^{\text{eq}}(E)=\arg\min_T{E/T-F(T)/T}$ and $ E^{\text{eq}}(T)=\arg\min_E{E-TS(E)}$ . ii) In contradistinction, taking derivative of the statistical free energy w.r.t. $ T$ , a mesoscopic energetics with fluctuations emerges: This yields two information entropy functions which historically appeared 50 years postdate Gibbs’ theory. iii) Combining the above pair of inequalities yields an irreversible thermodynamic potential $ \psi(T,E) \equiv {E-F(T)}/T-S(E)\ge 0$ for nonequilibrium states. The second law of thermodynamics as a universal principle reflects $ \psi\ge 0$ due to a disagreement between $ E$ and $ T$ as a dual pair. Our theory provides a new energetics of living cells which are nonequilibrium, complex entities under constant $ T$ , pressure $ p$ and chemical potential $ \mu$ . $ \psi$ provides a ``distance’’ between statistical data from a large ensemble of cells and a set of intrinsic energetic parameters that encode the information within.
Statistical Mechanics (cond-mat.stat-mech)
20 pages
Experimental demonstration of two distinct pathways of trion generation in monolayer MoS2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Faiha Mujeeb, Arkaprava Chowdhury, Anindya Datta, Subhabrata Dhar
Excitation power and energy dependent photoluminescence (PL) and transient absorption spectroscopy (TAS) studies are carried out on chemical vapour deposition (CVD) grown 1L-MoS2 films to understand the process of trion formation. The study shows that the excitation with sufficiently low photon energy results in the creation of trions directly in the K/K’ valleys through photon absorption followed by phonon scattering events. On the other hand, excitation energy sufficiently larger than the band-gap can generate the carriers away from the K/K’ valleys. Dissimilarity in the rates of relaxation of the photo-excited electrons and the holes to the bottom of the K/K’ valleys results in the transformation of the excitons residing there into trions. Our TAS study clearly demonstrates a temporary increase of the trion population in the K/K’ valleys. Moreover, excitation intensity dependent PL spectroscopy performed under above-band-gap excitation, also suggests the coexistence of both the pathways of trion generation in this material. This conclusion is further validated by a rate equation model. Our findings provide valuable insight into the formation of trions in monolayer transition metal dichalcogenides (TMDC), which could be crucial in designing valleytronic devices based on trions.
Materials Science (cond-mat.mtrl-sci)
Thomson problem on a spherical cap
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
We investigate the low-energy configurations of N mutually repelling charges confined to a spherical cap and interacting via the Coulomb potential. In the continuum limit, this problem was solved by Lord Kelvin, who found a non-uniform charge distribution with an integrable singularity at the boundary. To explore the discrete analogue, we developed an efficient numerical method that enables energy minimization while maintaining the number of charges at the cap’s edge fixed. Using this approach we have obtained numerical results for various values of N and cap angular widths. Based on these results, we analyze the emergence and behavior of topological defects as functions of both N and the cap’s curvature.
Soft Condensed Matter (cond-mat.soft), Computational Physics (physics.comp-ph)
12 pages; 20 figures
Effects of Near-Field Hydrodynamic Interactions on Bacterial Dynamics Near a Solid Surface
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Baopi Liu, Lu Chen, Haiqin Wang
Near-field hydrodynamic interactions between bacteria and no-slip solid surfaces are the main mechanism underlying surface entrapment of bacteria. In this study, we employ a chiral two-body model to simulate bacterial dynamics near the surface. The simulation results show that as bacteria approach the surface, their translational and rotational velocities, as well as their diffusion coefficients, decrease. Under the combination of near-field hydrodynamic interactions and DLVO forces, bacteria reach a stable fixed point in the phase plane and follow circular trajectories at this point. Notably, bacteria with left-handed helical flagella exhibit clockwise circular motion on the surface. During this process, as the stable height increases, the translational velocity parallel to the surface increases while the rotational velocity perpendicular to the surface decreases, collectively increasing the radius of curvature. Ultimately, our findings demonstrate that near-field hydrodynamic interactions significantly prolong the surface residence time of bacteria. Additionally, smaller stable heights further amplify this effect, resulting in longer residence times and enhanced surface entrapment.
Soft Condensed Matter (cond-mat.soft)
Non-Fermi-liquid transport phenomena in bilayer nickelates: Impact of quasi-quantum metric
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Seiichiro Onari, Daisuke Inoue, Rina Tazai, Youichi Yamakawa, Hiroshi Kontani
Recently discovered high-$ T_c$ superconductivity in thin-film bilayer nickelates La$ _3$ Ni$ _2$ O$ _7$ under ambient pressure has attracted great interest. Non-Fermi-liquid transport behaviors, such as $ T$ -linear resistivity and positive Hall coefficient increasing at low temperatures, have been reported in this system. In this study, we analyze the non-Fermi-liquid transport phenomena in the thin-film bilayer nickelate La$ _3$ Ni$ _2$ O$ _7$ using a multiorbital tight-binding model. In La$ _3$ Ni$ 2$ O$ 7$ , the orbital-selective cold spots composed of Ni $ d{x^2-y^2}$ orbital emerge since the spin fluctuations cause stronger quasi-particle damping $ \gamma$ in the Ni $ d{z^2}$ orbital. Notably, in the present study, we derive a rigorous formula for the Hall coefficient $ R_H$ incorporating the $ \gamma$ in the quasi-quantum metric (qQM) term. We discover that the $ T$ -dependence of $ \gamma$ in the qQM term is important in determining $ R_H$ , and that the qQM term is inevitably enhanced by the nearly degenerate bands at the orbital-selective cold spots located around $ (\pi/4,\pi/4)$ . Moreover, the qQM term plays an essential role in describing the Nernst coefficient and other transport phenomena involving the second derivative velocity $ v^{\mu\nu}$ . La$ _3$ Ni$ _2$ O$ _7$ provides a novel platform for exploring the physics of the qQM.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
11 pages, 12 figures
Twist-angle transferable continuum model and second flat Chern band in twisted MoTe2 and WSe2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Xiao-Wei Zhang, Kaijie Yang, Chong Wang, Xiaoyu Liu, Ting Cao, Di Xiao
We develop a twist-angle transferable continuum model for twisted transition metal dichalcogenide (tTMD) homobilayers, using tMoTe2 and tWSe2 as examples. All model parameters are extracted from density functional theory (DFT) calculations at a single twist angle (3.89°) and monolayer data. Our model captures both lattice relaxation effects and the long-range behavior of piezoelectric and ferroelectric potentials. Leveraging lattice relaxations obtained via machine learning force fields (MLFFs), the model can be efficiently transferred to other twist angles without requiring additional DFT calculations. It accurately reproduces the DFT band dispersions and quantum geometries across a wide range of twist angles. Furthermore, our model reveals that a second flat Chern band arises near 2° when the interlayer potential difference becomes comparable to the interlayer tunneling. This continuum model provides a clear understanding and starting point for engineering novel electronic phases in moiré TMDs through twist angles and lattice relaxations.
Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Accounting the size distribution of HTS granules for the critical current density from magnetic measurements
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
D. M. Gokhfeld, Yu. S. Gokhfeld
The determination of the critical current density from magnetic hysteresis loops is widely used to characterize and compare superconducting samples. Magnetic hysteresis loops for tapes and single crystals depend on both the critical current density and sample size. The latter sets the scale of supercurrent circulation. However, in polycrystalline high-temperature superconductors prepared by solid-phase synthesis or by sol-gel method, the magnetization is determined by the circulation of supercurrents in individual grains. The paper discusses the effect of the grain size distribution on the effective scale of current circulation. Log-normal and Weibull distributions are both considered as possible for grain sizes. The effective size for calculating the intragrain current density has been shown to be significantly larger than the average grain size.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
7 pages, 3 figures
Superconductivity: Fundamental and Applied Research 2(7) (2025) 52-58
Adhesion Control through Electric Field-Induced Water Adsorption at Oxidized Silicon Interfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Tunç Çiftçi, Jonathon Cottom, Rachid Hahury, Emilia Olsson, Bart Weber
Adhesion plays a pivotal role in computer chip manufacturing, directly affecting the precision and durability of positioning components such as wafer stages. Electrical biasing is widely employed to eliminate floating potential and to enable electrostatic clamping. However, upon electrical grounding adhesion can persist and there is limited knowledge about the nature of this adhesion hysteresis. Here, we investigate potential causes underlying electric field-induced adhesion hysteresis at the interface between an n-type AFM tip and a p-type silicon sample using atomic force microscopy. Our findings reveal that neither charge trapping nor siloxane bond formation significantly impacts the measured adhesion. Surprisingly, we show that adhesion can be tuned through electric field-induced water adsorption under low relative humidity (RH < 10%). Our results provide new insights into adhesion hysteresis and opportunities for adhesion control.
Soft Condensed Matter (cond-mat.soft)
How Machine Learning Predicts Fluid Densities under Nanoconfinement
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Fluids under nanoscale confinement differ – and often dramatically – from their bulk counterparts. A notorious feature of nanoconfined fluids is their inhomogeneous density profile along the confining dimension, which plays a key role in many fluid structural and transport phenomena in nanopores. Nearly five decades of theoretical efforts on predicting this phenomenon (fluid layering) have shown that its complexity resists purely analytical treatments; as a consequence, nearly all current approaches make extensive use of molecular simulations, and tend not to have generalizable predictive capabilities. In this work, we demonstrate that machine-learning-based models (in particular, a random forest model), trained upon large molecular simulation data sets, can serve as reliable surrogates in lieu of further molecular simulation. We show that this random forest model has excellent interpolative capabilities over a wide range of temperatures and confining lengthscales, and even has modest extrapolative ability. These results provide a promising pathway forward for developing models of nanoconfined fluid properties that are generalizable, lower cost than ``pure” molecular simulation, and sufficiently predictive for fluids-in-nanopores practitioners.}
Soft Condensed Matter (cond-mat.soft)
Mapping of Fermionic Lattice Models for Ising Solvers
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Lakshya Nagpal, Aditya Kumar, S. R. Hassan
We present an end-to-end, symmetry-aware pipeline that converts interacting fermionic and quantum-spin models into annealer-ready QUBOs while preserving low-energy physics. The workflow combines Bravyi-Kitaev encoding, exact Z2 symmetry tapering, Xia-Bian-Kais (XBK) diagonalization to a Z-only form, and k-local to 2-local quadratization, with ground energies recovered via a Dinkelbach fixed-point over the resulting Ising objective. We validate the approach across a complexity ladder: (i) a frustrated 2D Ising model run on a D-Wave Advantage QPU reproduces the known ferromagnet-stripe transition; (ii) finite-temperature checks on 1D Ising recover standard finite-size trends; (iii) a genuinely quantum spin target (XXZ) matches exact diagonalization (ED) on small chains; and (iv) interacting fermions (t-V) in 1D (rings L=2-8) show ED-level energies and the expected kink near V/t ~ 2, with a 2D 2x2 cluster tracking ED slopes up to a uniform offset. A replication-factor study quantifies the accuracy-overhead trade-off, with order-of-magnitude error reduction and diminishing returns beyond r ~ Nq. Except for the classical Ising benchmark and molecular benchmarks, experiments use D-Wave’s public DIMOD and Neal simulators; a molecular benzene case in the appendix illustrates portability beyond lattices. The results establish a practical pathway for mapping quantum matter to current annealers, with clear knobs for fidelity, resources, and embedding.
Strongly Correlated Electrons (cond-mat.str-el)
19 pages, 19 figures
Universal Machine Learning Potentials under Pressure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Antoine Loew, Jonathan Schmidt, Silvana Botti, Miguel A. L. Marques
Universal machine learning interatomic potentials (uMLIPs) represent arguably the most successful application of machine learning to materials science, demonstrating remarkable performance across diverse applications. However, critical blind spots in their reliability persist. Here, we address one such significant gap by systematically investigating the accuracy of uMLIPs under extreme pressure conditions from 0 to 150 GPa. Our benchmark reveals that while these models excel at standard pressure, their predictive accuracy deteriorates considerably as pressure increases. This decline in performance originates from fundamental limitations in the training data rather than in algorithmic constraints. In fact, we show that through targeted fine-tuning on high-pressure configurations, the robustness of the models can be easily increased. These findings underscore the importance of identifying and addressing overlooked regimes in the development of the next generation of truly universal interatomic potentials.
Materials Science (cond-mat.mtrl-sci)
X-ray magnetic circular dichroism originating from the $T_{z}$ term in collinear altermagnets under trigonal crystal field
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Norimasa Sasabe, Yuta Ishii, Yuichi Yamasaki
We investigate the microscopic origin and spectral features of X-ray magnetic circular dichroism (XMCD) in collinear antiferromagnets with trigonal crystal fields, using $ \alpha$ -MnTe as a prototypical example. Although such systems exhibit zero net magnetization, we demonstrate that XMCD can emerge from the anisotropic magnetic dipole operator $ T_{z}$ , arising from quadrupolar spin distributions. By constructing a complete multipole basis and analyzing the symmetry conditions under trigonal distortion, we identify specific spin and orbital configurations that enable a finite XMCD response. Further, we employ both one-electron and multi-electron models, including spin-orbit coupling and Coulomb interactions, to calculate the XMCD spectra for various $ d^n$ configurations. Our findings provide theoretical benchmarks for XMCD in altermagnets and highlight the key role of orbital symmetry and magnetic anisotropy in realizing observable dichroic effects.
Materials Science (cond-mat.mtrl-sci)
Kinetic contribution to the arbitrary order odd frequency moments of the dynamic structure factor
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-26 20:00 EDT
Panagiotis Tolias, Tobias Dornheim, Jan Vorberger
An exact expression is derived for the kinetic contribution to the odd (arbitrary order) frequency moments of the dynamic structure factor via a finite summation that features averages of even (all lower orders) powers of the momentum over the exact momentum distribution. The derivation is carried out for the non-interacting Fermi gas and generalized to the interacting case based on the conjecture that averages over the Fermi distribution can be substituted with averages over the exact distribution. The expression is validated against known results (first, third frequency moments) and new explicit calculations (fifth, seventh frequency moments).
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Plasma Physics (physics.plasm-ph)
10 pages, no figures
Theory of tunnel magnetoresistance in magnetic tunnel junctions with hexagonal boron nitride barriers: mechanism and application to ferromagnetic alloy electrodes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Ivan Kurniawan, Keisuke Masuda, Yoshio Miura
Hexagonal boron nitride ($ h$ -BN), with its strong in-plane bonding and good lattice match to hcp and fcc metals, offers a promising alternative barrier material for magnetic tunnel junctions (MTJs). Here, we investigate spin-dependent transport in hcp-Co$ _{1-x}$ Ni$ _{x}$ /$ h$ -BN$ /$ hcp-Co$ _{1-x}$ Ni$ _{x}$ (0001) MTJs with physisorption-type interfaces using first-principles calculations. We find that a high TMR ratio arises from the resonant tunneling of the down-spin surface states of the hcp-Co$ _{1-x}$ Ni$ _{x}$ , having a $ \Delta_1$ -like symmetry around the $ \Gamma$ point. Ni doping tunes the Fermi level and enhances this effect by reducing the overlap between up-spin and down-spin conductance channels in momentum space under the parallel configuration, thereby suppressing antiparallel conductance and increasing the TMR ratio. This mechanism is analogous to Brillouin zone spin filtering and is sensitive to the interfacial distance but not specific to $ h$ -BN barriers; similar behavior may emerge in MTJs with other two-dimensional insulators or semiconductors. These findings provide insight into surface-state-assisted tunneling mechanisms and offer guidance for the interface engineering of next-generation spintronic devices.
Materials Science (cond-mat.mtrl-sci)
Zeeman Ladders in Frustrated XYZ Spin Chains
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Catalin-Mihai Halati, Viola Romerio, Paul Steffens, J. Ross Stewart, Andrey Zheludev, Thierry Giamarchi
We investigate the nature of the excitations captured by the dynamical response of XYZ triangular spin-1/2 ladders. We complement experimental inelastic neutron scattering results on the compound $ \text{Cs}\text{2}\text{CoBr}\text{4}$ with numerically exact simulations based on time-dependent matrix product state methods. Our results show that bound states of spinon excitations can arise in XYZ beyond the requirement of strong Ising anisotropies. We analyze the role of the frustrated triangular couplings on the excitations giving rise to the spin dynamical structure factor and show how the features of the bound states manifest themselves in the different polarization channels.
Strongly Correlated Electrons (cond-mat.str-el)
Three-dimensional electronic domain correlations in 1T-TaS2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Corinna Burri, Henry G. Bell, Faris Dizdarević, Wenxiang Hu, Jan Ravnik, Jakub Vonka, Yasin Ekinci, Shih-Wen Huang, Simon Gerber, Nelson Hua
The interplay of nanoscale electronic domains underpins many emergent phenomena of quantum materials, including the competition between charge density waves (CDW) and superconductivity in high-Tc cuprates, or the storage of information in phase-change memory devices. Coupling to electronic domains provides an observable for pinpointing key interactions, e.g. affecting phase transitions. While the equilibrium phase diagram of 1T-TaS2 - characterized by unique transport properties and varying degrees of CDW commensurability - has been studied extensively, an understanding of how the electronic domains in the bulk behave across phase boundaries is lacking. We reveal the three-dimensional evolution of electronic domains in 1T-TaS2 using temperature-dependent X-ray diffraction and reciprocal space mapping, complemented by structure factor simulations based on the Hendricks-Teller method. With this methodology, we identify an increasing number of stacking faults near the phase transitions, and a growing fraction of dimerized layers in the commensurate phase upon cooling. We provide structural evidence that the CDW domains mediate the transport properties at phase boundaries, and that they also account for an anomalous intermediate electronic phase within the triclinic regime upon heating. As a paradigmatic material with potential in phase-change memory applications, our study underscores the importance of domain sizes and layer stacking in defining electronic behaviors of van der Waals materials.
Strongly Correlated Electrons (cond-mat.str-el)
Unveiling the landscape of Mottness and its proximity to superconductivity in 4Hb-TaS$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Ping Wu, Zhuying Wang, Yunmei Zhang, Ziyan Chen, Shuikang Yu, Wanru Ma, Min Shan, Zeyu Liang, Xiaoyu Wei, Junzhe Wang, Wanlin Cheng, Zuowei Liang, Xuechen Zhang, Tao Wu, Yoshinari Okada, Kun Jiang, Zhenyu Wang, Xianhui Chen
Mott physics is at the root of a plethora of many-body quantum phenomena in quantum materials. Recently, the stacked or twisted structures of van der Waals (vdW) materials have emerged as a unique platform for realizing exotic correlated states in the vicinity of the Mott transition. However, the definitive feature of Mottness and how it rules the low-energy electronic state remain elusive and experimentally inaccessible in many interesting regimes. Here, we quantitatively describe a filling-controlled Mott state and its interplay with superconductivity by scanning tunnelling spectroscopy in a vdW bulk heterostructure, 4Hb-TaS$ _2$ , that interleaves strongly correlated 1T-TaS$ _2$ layers with superconducting 1H-Ta$ _2$ layers. The fine tunability of electron doping induced by interlayer charge transfer allows us to continuously track the spectral function with unsurpassed energy resolution from a depleted narrow band (0.2 electrons per site) toward a Mott transition at half filling. The gradually emerging Mott-Hubbard bands, followed by the sharpening and vanishing of the central quasiparticle peak as predicted in the Brinkman-Rice scenario, unambiguously demonstrate the Mott physics at play. Importantly, the renormalization of the low-energy electrons acts destructively on the superconducting pairing potential, leaving behind nonsuperconducting, paramagnetic puddles at the nanoscale. Our results reveal a seminal system near the border of the Mott criterion that enables us to illustrate the predictive power of the Hubbard model, and set such heterostructures as promising ground for realizing new correlated states in the heavily doped Mott regime.
Superconductivity (cond-mat.supr-con)
15 pages, 4 figures
Symmetry Classification of Altermagnetism and Emergence of Type-IV Magnetism in Two Dimensions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Mu Tian, Chaoxi Cui, Zeying Zhang, Jingyi Duan, Wanxiang Feng, Run-Wu Zhang
Two-dimensional (2D) magnetism, particularly 2D altermagnetism (AM), has attracted considerable interest due to its exceptional physical properties and broad application potential. However, the classification of AM undergoes a fundamental paradigm shift when transitioning from three-dimensional (3D) to 2D symmetry-enforced fully compensated collinear magnetism$ -$ a shift that has remained largely overlooked. Here, by extending unconventional magnetism to 2D collinear systems, we identify the symmetry conditions and electronic band characteristics of a distinct magnetic phase: type-IV magnetism. This new class lies beyond the established descriptions of ferromagnetism, conventional antiferromagnetism, and AM. Type-IV magnetism supports the successive emergence of both nonrelativistic spin-degenerate and relativistic spin-splitting phenomena, belonging strictly to neither conventional antiferromagnetism nor standard AM. We further establish a universal symmetry classification framework for 2D type-IV magnets via a mapping from the collinear spin layer group to the magnetic layer group. Monolayer MgCr$ _2$ O$ _3$ and monolayer BaMn$ _2$ Ch$ _3$ (Ch=Se, Te) are showcased as representative materials, exhibiting gate-tunable reversible spin textures and the quantum electric Hall effect, respectively. Our work underscores the rich functional prospects of type-IV magnets, offering a new route toward spin manipulation and anomalous transport that promises innovative designs for high-performance spintronic devices.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Amorphous $CaSO_{4}$ nanocrystal deposits for friction and wear reduction at silicon interfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Tijn Vernooij, Tunç Çiftçi, Noushine Shahidzadeh, Bart Weber
When an object is placed on a surface, friction and wear cause uncertainty in its exact position, and thus challenge precision manufacturing. Here, we explore the development of a sacrificial nanocrystal deposit that can suppress friction and wear. Amorphous \ce{CaSO4} nancrystals are deposited through salt solution droplet deposition followed by evaporation. During droplet drying, a precursor film of the aqueous \ce{CaSO4} solution spreads onto a hydrophilic silicon wafer, thus nucleating evenly spread unfaceted amorphous nanocrystals of \ce{CaSO4} on the wafer surface. We used atomic force microscopy to study the extent, topography, and friction and wear behavior of the deposited nanocrystals. We find that the sacrificial layer of nanocrystals is easy to apply and remove, spreads over large (few cm) areas with a constant thickness of about 8 nm, and has favorable friction and wear behavior.
Soft Condensed Matter (cond-mat.soft)
General Learning of the Electric Response of Inorganic Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Bradley A. A. Martin, Alex M. Ganose, Venkat Kapil, Keith T. Butler
We present MACE-Field, a field-aware $ O(3)$ -equivariant interatomic potential that provides a compact, derivative-consistent route to dielectric properties (such as polarisation $ \mathbf P$ , Born effective charges $ Z^\ast$ and polarisability $ \boldsymbol\alpha$ ) and finite-field simulations across chemistry for inorganic solids. A uniform electric field is injected within each message-passing layer via a Clebsch-Gordan tensor-product which couples the field to latent spherical-tensor features, and perturbs them via an equivariant residual mixing. This plug-in design preserves the standard MACE readout and can inherit existing MACE foundation weights, turning pretrained models into field-aware ones with minimal change. To demonstrate, we train: (i) a cross-chemistry ferroelectric polarisation model (2.5k nonpolar$ !\to$ polar polarisation branches), (ii) a cross-chemistry BECs/polarisability model ($ \sim$ 6k Materials Project dielectrics spanning 81 elements), and (iii-iv) single-material molecular dynamics on BaTiO$ _3$ and $ \alpha$ -SiO$ 2$ . The models recover polarisation branches and spontaneous polarisation, predict $ Z^\ast$ and $ \boldsymbol\alpha$ (hence $ \varepsilon\infty$ ) across diverse chemistries, and reproduce BaTiO$ _3$ hysteresis and the IR/Raman and dielectric spectra of $ \alpha$ -quartz, benchmarking comparatively with Allegro-pol.
Materials Science (cond-mat.mtrl-sci)
16 pages, 6 figures, 32 equations
Hydrodynamic instabilities in driven chiral suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Seema Chahal, Brato Chakrabarti
Active Stokesian suspensions are conventionally understood to generate dipolar stresses that destabilize aligned states in the bulk and drive system-wide spatiotemporally chaotic flows. Here, we report dynamics in suspensions of torque-driven spinning chiral particles that exhibit a distinct and previously unrecognized route to collective dynamics. Using a mean-field kinetic theory, stability analysis, and nonlinear simulations, we demonstrate how flows driven by torque monopoles and self-propulsion resulting from microscopic chirality drive chaotic flows in three dimensions. Unlike the well-known alignment instability of dipolar active matter, the present dynamics is intrinsically tied to self-propulsion and relies on the emergent coupling between nematic and polar order. Our results establish a novel route to pattern formation, suggest strategies for designing torque-driven active suspensions, and provide a mechanistic framework to probe the rheology of chiral fluids.
Soft Condensed Matter (cond-mat.soft)
5 pages, 3 figures
Hyperfine interaction of electrons confined in CsPbI$_3$ nanocrystals with nuclear spin fluctuations
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Sergey R. Meliakov, Evgeny A. Zhukov, Vasilii V. Belykh, Kirill V. Kavokin, Mikhail O. Nestoklon, Elena V. Kolobkova, Maria S. Kuznetsova, Manfred Bayer, Dmitri R. Yakovlev
The coherent spin dynamics of electrons are investigated for CsPbI$ _3$ perovskite nanocrystals in a glass matrix using time-resolved Faraday ellipticity. In nanocrystals with a diameter of about 11 nm, the Larmor precession frequency has a linear dependence on magnetic field corresponding to the electron Landé $ g$ -factor of 2.07. We find a finite Larmor precession frequency at zero magnetic field, corresponding to the electron spin splitting of $ 0.8$ $ \mu$ eV. This splitting is explained by the hyperfine interaction with nuclear spin fluctuations. Our model analysis shows that the hyperfine interaction for the conduction band electrons is contributed both by the $ p$ -orbitals of the lead atoms and by the $ s$ -orbitals of the iodine atoms, with the leading contribution to the hyperfine field fluctuations coming from iodine. This fact agrees well with the 9% iodine contribution to the Bloch amplitude of the conduction band, obtained by DFT calculations. From these findings, the atomic hyperfine constant for the $ 5s$ -orbital of iodine is evaluated as 190 $ \mu$ eV.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Realizing an Atomtronic AQUID in a Rotating-Box Potential
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-26 20:00 EDT
Kaspar Görg, Ludwig Mathey, Vijay Pal Singh
Atomtronic devices are matter-wave circuits designed to emulate the functional behavior of their electronic counterparts. Motivated by superconducting quantum interference devices (SQUIDs), atomic quantum interference devices (AQUIDs) have been developed using Bose-Einstein condensates (BECs) confined in toroidal geometries. Here, we propose and numerically investigate an alternative implementation of an AQUID based on a BEC confined in a rotating box potential. A ring-like topology is established by introducing a central depletion region via a repulsive potential barrier. We observe the hallmark AQUID feature – quantized phase winding that increases in discrete steps with angular velocity. Centrifugal effects induced by rotation degrade phase coherence and impair AQUID performance, which we mitigate by applying a counteracting harmonic confinement. Phase slips are found to be mediated by a vortex propagating from the central depletion zone to the edge of the condensate. To characterize the voltage response, we induce a bias current by translating the box along its long axis while keeping the central barrier fixed. This generates a density imbalance between the two reservoirs, exhibiting a periodic dependence on angular velocity – analogous to the voltage-flux relation in electronic SQUIDs. Our results demonstrate that rotating box geometries provide a viable and flexible platform for realizing atomtronic AQUIDs with controllable dynamics and well-defined response characteristics.
Quantum Gases (cond-mat.quant-gas)
10 pages, 8 figures
Wurtzite MnSe as a barrier for CdSe quantum wells with built-in electric field
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
M. J. Grzybowski, W. Pacuski, J. Suffczyński
Altermagnetic materials have attracted a lot of attention recently due to the numerous effects, which have an application potential and occur due to the spin-split band structure coexisting with the compensated magnetic order. Incorporation of such intriguing compounds into low-dimensional structures represents an important avenue towards exploiting and enhancing their functionalities. Prominent examples of this group are semiconductors well suited to the band-gap engineering strategies. Here, we present for the first time visible-light-emitting CdSe quantum wells, in which wurtzite MnSe as an alermagnetic candidate plays the role of a barrier. Photoluminescence experiments with temporal resolution demonstrate that in such quantum wells, a built-in electric field is present and strongly influences the energies of the emitted photons, the dynamics of recombination, and excitation power dependence. Numerical simulations allow us to estimate that the magnitude of the electric field is 14MV/m. We anticipate that such quantum wells offer potential to probe the barrier properties and that wurtzite MnSe is an interesting platform to study the interplay of the altermagnetism and built-in electric field.
Materials Science (cond-mat.mtrl-sci)
Finite temperature single-particle Green’s function in the Lieb-Liniger model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-26 20:00 EDT
Riccardo Senese, Fabian H. L. Essler
We develop a Monte Carlo sampling algorithm to numerically evaluate the Lehmann representation for the finite temperature single-particle Green’s function in the repulsive Lieb-Liniger model. This allows us to determine the spectral function in the full range of temperatures and interactions, as well as in generalized Gibbs ensembles. We test our results against the known limit of infinite interaction strength and find excellent agreement.
Statistical Mechanics (cond-mat.stat-mech), Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
7 + 12 pages, 16 figures
Physical Embodiment Enables Information Processing Beyond Explicit Sensing in Active Matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Diptabrata Paul, Nikola Milosevic, Nico Scherf, Frank Cichos
Living microorganisms have evolved dedicated sensory machinery to detect environmental perturbations, processing these signals through biochemical networks to guide behavior. Replicating such capabilities in synthetic active matter remains a fundamental challenge. Here, we demonstrate that synthetic active particles can adapt to hidden hydrodynamic perturbations through physical embodiment alone, without explicit sensing mechanisms. Using reinforcement learning to control self-thermophoretic particles, we show that they learn navigation strategies to counteract unobserved flow fields by exploiting information encoded in their physical dynamics. Remarkably, particles successfully navigate perturbations that are not included in their state inputs, revealing that embodied dynamics can serve as an implicit sensing mechanism. This discovery establishes physical embodiment as a computational resource for information processing in active matter, with implications for autonomous microrobotic systems and bio-inspired computation.
Soft Condensed Matter (cond-mat.soft), Robotics (cs.RO)
Optimization of superconducting properties of F-doped SmFeAsO by cubic anvil high-pressure technique
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Mohammad Azam, Tatiana Zajarniuk, Hiraku Ogino, Shiv J. Singh
We optimize the synthesis conditions for SmFeAsO0.80F0.20 (Sm1111) bulks using a cubic-anvil high-pressure (CA-HP) apparatus through both ex-situ and in-situ processes, applying pressures of up to 4 GPa and heating temperatures of up to 1600°C. A comprehensive characterization has been performed, including structural, microstructural, transport, and magnetic measurements. Our findings indicate that a modest growth pressure of approximately 0.5 GPa is sufficient for the formation of the Sm1111 phase in the ex-situ process. In contrast, the in-situ process requires higher synthesis pressure (4 GPa) and temperature (1400 °C for 1 hour) to achieve the Sm1111 phase with enhanced superconducting properties. Notably, the optimized in-situ process significantly reduces the reaction time needed for the formation of the Sm1111 phase compared to conventional synthesis process at ambient pressure (CSP), leading to an increase in the transition temperature by 3 K and improvements in critical current density (Jc). Conversely, the optimized ex-situ process results in an onset transition temperature (Tc) of approximately 53 K, similar to that of CSP, though it enhances the Jc by an order of magnitude. Despite these advancements, a small amount of impurity phases, as observed during CSP, persists in all Sm1111 samples prepared through either the in-situ or ex-situ CA-HP processes. These results suggest that the in-situ process under optimized conditions (1400 °C, 4 GPa for 1 hour) can effectively improve the superconducting properties of Sm1111. Additionally, a comprehensive analysis comparing these results with high gas pressure techniques, spark plasma sintering, and CSP methods suggests that a small amount of impurity phases in Sm1111 is persistent and cannot be completely eliminated by various pressure techniques, even at the applied pressure of up to 4 GPa.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
44 pages, 15 figures
Graph atomic cluster expansion for foundational machine learning interatomic potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Yury Lysogorskiy, Anton Bochkarev, Ralf Drautz
Foundational machine learning interatomic potentials that can accurately and efficiently model a vast range of materials are critical for accelerating atomistic discovery. We introduce universal potentials based on the graph atomic cluster expansion (GRACE) framework, trained on several of the largest available materials datasets. Through comprehensive benchmarks, we demonstrate that the GRACE models establish a new Pareto front for accuracy versus efficiency among foundational interatomic potentials. We further showcase their exceptional versatility by adapting them to specialized tasks and simpler architectures via fine-tuning and knowledge distillation, achieving high accuracy while preventing catastrophic forgetting. This work establishes GRACE as a robust and adaptable foundation for the next generation of atomistic modeling, enabling high-fidelity simulations across the periodic table.
Materials Science (cond-mat.mtrl-sci)
Role of interlayer shear phonons on the lattice symmetry switch in a transition-metal dichalcogenide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Mizuki Akei, Takumi Fukuda, Yu Mizukoshi, Kazuhiro Kikuchi, Muneaki Hase
Coherent phonon control using ultrashort pulse trains is the key to realizing structural phase transitions in solids by non-thermal pathways. By combining double-pulse excitation and time-resolved second harmonic generation techniques under high-density electronic excitation in a 2D layered material, WTe$ _{2}$ , we demonstrate that the lattice symmetry switching from the Weyl semimetallic T$ _{d}$ to the semimetallic 1T$ ^{\prime}$ phases is independent of the amplitude of the coherent interlayer shear phonons. This finding provides new insights into the mechanisms for symmetry switching that electronic excitation-driven shear sliding plays a dominant role.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures, 6 supplemental figures, 1 supplemental table
Numerical investigations around the Gallavotti-Cohen Fluctuation Theorem on Log-lattices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-26 20:00 EDT
Guillaume Costa (CEA), Bérengère Dubrulle (CEA)
Using the recent concept of fluids projected onto Log-Lattices, we investigate the validity of the Gallavotti-Cohen Fluctuation Theorem (GCFT) in the context of fluid mechanics. The dynamics of viscous flows are inherently irreversible, which violates a fundamental assumption of the fluctuation theorem. To address this issue, Gallavotti introduced a new model, the Reversible Navier-Stokes Equation (RNS), which recovers the time-reversal symmetry of the Navier-Stokes (NS) equations while retaining the core characteristics of the latter. We show that for fluids on Log-Lattices, the GCFT holds for the RNS system. Furthermore, we show that this result can be extended, under certain assumptions, to the traditional, irreversible Navier-Stokes equations. Additionally, we show that the phase space contraction rate satisfies a large deviation relation which rate function can be estimated.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph), Fluid Dynamics (physics.flu-dyn)
Driving a stimuli-responsive wedge in the packing of phospholipid membranes using bolaamphiphile intercalants
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
Niki Baccile (LCMCP-SMiLES), Archan Vyas (UC Davis), Ramanujam Ramanujam (LCMCP-SMiLES), Daniel Hermida-Merino, Ingo Hoffmann (ILL), Lionel Porcar (ILL), Atul N. Parikh (UC Davis)
Bolaamphiphilesamphiphilic molecules with polar groups at each of the two ends of a hydrophobic tail with pH-sensitive spontaneous molecular curvaturesendow membranes of extremophiles with an exquisite balance between stability (or robustness) and adaptability (or plasticity). But how the presence (or real-time insertion) of bolaamphiphiles influences lamellar lipid membranes is poorly understood. Using a combination of time-resolved confocal fluorescence microscopy, in situ small angle X-ray and neutron scattering (SAXS, SANS), and neutron spin echo (NSE) measurements, we monitor here the pH-dependent interactions of nanoscopic vesicles of a representative bolaamphiphilea glucolipid consisting of a single glucose headgroup and a C18:1 (oleyl) fatty acid tail (G-C18:1)with the membranes of an essentially cylindrical, fluid-phase phospholipid (dioleoylphosphatidylcholine, DOPC). We find that the two mesophases interact spontaneously at all pH values, producing large-scale morphological remodeling. Under neutral and acidic conditions, when the bolaamphiphile assumes a cylindrical shape, vesicles fuse with one another, producing invaginations, inner tubulation and vesicle-in-vesicle aggregates. Under basic pH, by contrast, when the carboxylic acid is deprotonated and the molecule is inverted-conical in shape, the bolaamphiphile causes phospholipid membranes to undergo poration, budding, and vesiculation. This pH-dependent, environmentally sensitive membrane remodeling without the disruption of the essential bilayer motif illustrates how local, molecular-level packing perturbations can translate into global system-level morphological changes, enabling membranes to acquire environmental sensitivity and real-time adaptability. These results support the notion that molecular fluxeswhich add (or remove) amphiphilic molecules to biological membranescan endow de novo functionalities (e.g., pH sensitivity) and influence global morphologies of cell-sized vesicles.
Soft Condensed Matter (cond-mat.soft)
Antiferromagnetic Skyrmion Scattering Revealed by Direct Time-Resolved Imaging of Collective Dynamics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Mona Bhukta, Takaaki Dohi, Kilian Leutner, Maria-Andromachi Syskaki, Fabian Kammerbauer, Duc Minh Tran, Sebastian Wintz, Markus Weigand, Robert Frömter, Mathias Kläui
Scattering analysis offers a fundamental route to revealing particle interactions with direct implications for device technologies relying on ensembles of particles such as magnetic skyrmions. Here, we directly visualize, in real time, the nanosecond current-driven dynamics of an antiferromagnetic (AFM) skyrmion lattice using element-specific pump-probe X-ray microscopy. By tuning spin-orbit torque relative to local pinning potentials, we reveal two regimes: incoherent flow, where mobile skyrmions scatter from pinned ones, inducing recoil dynamics with 3-20 ns relaxation, and coherent flow, where the lattice translates uniformly. Quantification of the reproducible post-pulse relaxation trajectories via an inverse analyis method based on the Thiele equation yields the nanoscale AFM skyrmion-skyrmion scattering potential, which decays exponentially with a range of 30 nm, in full agreement with micromagnetic simulations. At higher current densities, the lattice exhibits coherent motion free from detectable Hall and inertial effects or dynamical deformation, enabling robust GHz operation. These findings establish a quantitative framework for AFM skyrmion interactions and demonstrate deterministic control of their collective dynamics over billions of cycles even in the incoherent flow regime, thereby paving the way for multi-skyrmion spintronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
21 pages, 5 figures
Ab initio study of anomalous temperature dependence of resistivity in V-Al alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
V$ _{1-x}$ Al$ _x$ is a representative example of highly resistive metallic alloys exhibiting a crossover to a negative temperature coefficient of resistivity (TCR), known as the Mooij correlation. Despite numerous proposals to explain this anomalous behavior,none have provided a satisfactory quantitative explanation thus far. In this work, we calculate the electrical conductivity using an ab initio methodology that combines the Kubo-Greenwood formalism with the coherent potential approximation (CPA). The temperature dependence of the conductivity is obtained within a CPA-based model of thermal atomic vibrations. Using this approach, we observe the crossover to the negative TCR behavior in V$ _{1-x}$ Al$ _x$ , with the temperature coefficient following the Mooij correlation, which matches experimental observations in the intermediate-to-high temperature this http URL of the results allows us to clearly identify a non-Boltzmann contribution responsible for this behavior and describe it as a function of temperature and composition.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Incompressible quantum liquid on the four-dimensional sphere
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Junwen Zhao, Xue Meng, Wei Zhu, Congjun Wu
The study of quantum Hall effect (QHE) is a foundation of topological physics, inspiring extensive explo- rations of its high-dimensional generalizations. Notably, the four-dimensional (4D) QHE has been experi- mentally realized in synthetic quantum systems, including cold atoms, photonic lattices, and metamaterials. However, the many-body effect in the 4D QHE system remains poorly understood. In this study, we explore this problem by formulating the microscopic wavefunctions inspired by Laughlin’s seminal work. Employing a generalized pseudo-potential framework, we derive an exact microscopic Hamiltonian consisting of two-body projectors that annihilate the microscopic wavefunctions. Diagonalizations on a small size system show that the quasi-hole states remain zero energy while the quasi-particle states exhibit a finite gap, in consistency with an incompressible state. Furthermore, the pairing distribution is calculated to substantiate the liquid-like nature of the wavefunction. Our work provides a preliminary understanding to the fractional topological states in high dimension.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other), Quantum Gases (cond-mat.quant-gas), High Energy Physics - Theory (hep-th)
7 pages,3 figures
Crystalline-to-Crystalline Phase Transition between Germanium Selenide Polymorphs with High Resistance Contrast
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Joonho Kim, Kihyun Lee, Joong-Eon Jung, Han Joo Lee, Seongil Im, Kwanpyo Kim
Understanding phase transitions between crystalline phases of a material is crucial for both fundamental research and potential applications such as phase-change memory. In this study, we investigate the phase transition between GeSe crystalline polymorphs induced by either global annealing at moderate temperatures or localized laser-induced heating. The highly conductive gamma-GeSe transforms into semiconducting, single-crystalline alpha-GeSe while preserving a well-aligned crystal orientation. The distinct structural and electronic properties at the gamma-GeSe/alpha-GeSe interface were investigated by transmission electron microscopy analysis. We propose that the clustering of Ge vacancies in the gamma-GeSe phase at elevated temperatures is a key mechanism driving the transition, leading to the formation of alpha-GeSe through the segregation of a minor GeSe2 phase. Furthermore, we observe a high electrical resistance contrast of approximately 10^7 between gamma-GeSe and alpha-GeSe, underscoring the potential of GeSe as a model polymorphic system for electronic applications, including phase-change memory.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
25 pages, 4 figures
Dispersion interaction of two graphene sheets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
The Casimir method for determining the dispersive force by varying zero vacuum energy fluctuations is applied to two graphene sheets in the approximation of the Drude model for surface conductivity. As an alternative, the Van Kampen summation method is used. The force is determined for small and for large distances between the sheets. The results of both models are quite similar. Precisely, at large distances, the attractive force decreases inversely proportional to the fourth power of the distance. At short distances, the force is a finite attractive one. With a small chemical potential, the force can have a minimum at distances of the order of 0.3 nm, then increases, reaches a maximum at distances of the order of 200 nm, and at large distances decreases inversely proportional to the fourth power of the distance. At a chemical potential of significantly more than 1 eV, a minimum is not observed.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
37 pages, figures. 1 table, 47 references
Room-temperature anisotropic in-plane spin dynamics in graphene induced by PdSe$_2$ proximity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Juan F. Sierra, Josef Světlík, Williams Savero Torres, Lorenzo Camosi, Franz Herling, Thomas Guillet, Kai Xu, Juan Sebastián Reparaz, Vera Marinova, Dimitre Dimitrov, Sergio O. Valenzuela
Van der Waals heterostructures offer a versatile platform for tailoring electrical, magnetic, optical, and spin transport properties of materials through proximity effects. Notably, hexagonal transition metal dichalcogenides have been shown to induce valley-Zeeman spin-orbit coupling (SOC) in graphene, resulting in significant spin lifetime anisotropy between in-plane and out-of-plane spin orientations. However, in-plane lifetimes remain isotropic due to the inherent threefold symmetry of the heterostructure. Here, we demonstrate that pentagonal PdSe$ _2$ , characterised by unique in-plane anisotropy, induces an unprecedented gate-tunable SOC in graphene. Our measurements reveal a remarkable 10-fold modulation of the spin lifetime for spins oriented within the graphene plane at room temperature. Moreover, the directional dependence of the spin lifetimes, along the three spatial directions, suggests the existence of a persistent in-plane spin texture component that dominates the spin dynamics. These findings deepen our understanding of spin dynamics in van der Waals heterostructures and open avenues for designing and engineering novel topological phases in graphene-based heterostructures within the strong SOC regime.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Nature Materials 24, 876-882 (2025)
Highly anisotropic 1D materials supported in exfoliable 2D coordination polymers with optical anisotropy switching via twist-engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Eleni C. Mazarakioti, Carla Boix-Constant, Iván Gómez-Muñoz, Diego López-Alcalá, Sergio Revuelta, Marco Ballabio, Vasileios Balos, José J. Baldoví, Enrique Cánovas, Josep Canet-Ferrer, Guillermo Mínguez Espallargas, Samuel Mañas-Valero, Eugenio Coronado
Van der Waals (vdW) materials provide a platform to study and control the physical properties of low-dimensional materials. While strategies developed for two-dimensional (2D) crystals are not directly transferable to one-dimensional (1D) systems, we can benefit from them by creating layers formed by interconnected chains. Here, we develop a molecular strategy to illustrate this concept consisting of assembling 1D materials in 2D metal-organic frameworks (MOFs). Crystals of [FeX(pzX)(bpy)] (X = Cl, F; pz = pyrazole; bpy = bipyridine) consist of iron chains along the b-axis, crosslinked via bpy ligands along the a-axis to form 2D layers, stacked along the c-axis via vdW forces. This structural anisotropy manifests itself in highly-anisotropic optical properties, as demonstrated by optical measurements in the visible and terahertz ranges, results which are supported by DFT calculations. Chemical substitution enables the tuning of the optical properties, as exemplified by the photoluminescence of the Cl-derivative, which is quenched for the F-derivative. Thin-layers are obtained by mechanical exfoliation, and their optical properties are further tuned through the fabrication of orthogonally-twisted vdW heterostructures, enabling to effectively switch-off the optical anisotropy. Our work highlights the chemical flexibility of vdW layered MOFs as a platform for designing and manipulating 1D architectures.
Materials Science (cond-mat.mtrl-sci)
24 pages, 5 figures
Optical formation of ultracold NaK$_2$ ground state molecules
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-26 20:00 EDT
Baraa Shammout, Leon Karpa, Silke Ospelkaus, Eberhard Tiemann, Olivier Dulieu
We study the rovibronic transitions in NaK$ _2$ between its electronic ground state $ 1^2A’$ and its second excited state $ 3^2A’$ , to identify possible pathways for the creation of ultracold ground-state triatomic molecules. Our methodology relies on the computation of potential energy surfaces and transition dipole moment surfaces for the relevant electronic states using ab initio methods. Rovibrational energy levels and wave functions are determined using the discrete variable representation approach. A double-well structure of the potential energy surface is identified for both states, and the related transition strengths between the rovibrational levels are derived. Our calculations show that the formation of ultracold ground-state NaK$ _2$ molecules is expected when starting from an excited electronic state of NaK$ _2$ , which can be created by photoassociation of NaK and K observed by optical means by Cao et al. (Phys. Rev. Lett. 2024, 132, 093403).
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Chemical Physics (physics.chem-ph)
Polarization- and time-resolved nonlinear multi-photon spectroscopy for confocal microscopy of semiconductor nanostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Nikita V. Siverin, Andreas Farenbruch, Dmitri R. Yakovlev, Daniel J. Gillard, Xuerong Hu, Alexander I. Tartakovskii, Manfred Bayer
We present a versatile confocal microscopy setup for optical second harmonic generation (SHG) and multi-photon spectroscopy that enables polarization-resolved studies of semiconductor bulk crystals and low-dimensional structures. The system offers full polarization control in both excitation and detection, spatial scanning with micrometer resolution, and spectrally tunable excitation over a broad energy range from 0.5 to 4.0 eV, using femtosecond and picosecond laser pulses. Samples are mounted in a helium-flow cryostat, allowing temperature control from 4 to 300 K. Magnetic fields up to 0.625 T can be applied in the Voigt geometry via an electromagnet. The nonlinear optical signals are analyzed using a high-resolution spectrometer with a spectral resolution of 60 $ \mu$ eV. We demonstrate the potential of the setup by means of SHG polarization tomography measurements on a Cu$ _2$ O crystal as well as through a SHG spectral scan of a ZnSe crystal over a wide energy range from 1.4 to 3.1 eV. Polarization-resolved confocal SHG mapping of various twisted mono- and bilayer MoS$ _2$ structures is also presented. In addition, time-resolved two-color pump-probe experiments are shown for a Cs$ _2$ AgBiBr$ _6$ crystal, illustrating the potential of the system for investigating coherent exciton and phonon dynamics.
Materials Science (cond-mat.mtrl-sci)
Numerical validation of an ultracold Hubbard quantum simluator
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-26 20:00 EDT
Ben Currie, John Sturt, Evgeny Kozik
We apply the formally exact Diagrammatic Monte Carlo (DiagMC) method to probe the unprecedentedly low-temperature regime recently achieved in an ultracold-atom quantum simulation of the 2D Hubbard model [Xu et al., Nature 642, 909 (2025)]. Computing the experimentally measured observables directly in the thermodynamic limit with a priori control of systematic errors, we find striking agreement with the experimental data across all accessible temperatures – including the lowest, where existing numerical benchmarks show significant deviations. This validates the quantum simulator’s control over systematic errors in this challenging regime and delivers unbiased benchmarks for future method development. Our results demonstrate that classical algorithms remain competitive with state-of-the-art analogue quantum simulators, and emphasise the importance of controlled numerical methods for continuing the development of these experiments.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures
Anomalous narrow-band correlation in a natural superconducting heterostructure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Xiupeng Sun, Zhiyuan Wei, Min Shan, Shuting Peng, Yang Luo, Jianchang Shen, Linwei Huai, Yu Miao, Zhipeng Ou, Mehmet Onbasli, Zhenyu Wang, Tao Wu, Junfeng He, Xianhui Chen
A new frontier in condensed matter physics is to stack atomically thin layered-materials with different properties and create intriguing phenomena which do not exist in any of the constituent layers. Transition metal dichalcogenide 4Hb-TaS$ _2$ , with an alternating stacking of a spin liquid candidate 1T-TaS$ _2$ and a superconductor 1H-TaS$ _2$ , is a natural heterostructure for such a purpose. Recently, rare phenomena are indeed observed, including chiral superconductivity, two-component nematic superconductivity, topological surface superconductivity and enigmatic magnetic memory. A widely proposed starting point to understand such a mysterious heterostructure requires strong electronic correlation, presumably provided by 1T-TaS$ _2$ layers with a narrow flat band near the Fermi level ($ E_F$ ). Here, by using angle-resolved photoemission spectroscopy, we reveal the theoretically expected flat band near $ E_F$ in the energy-momentum space for the first time. However, this flat band only exists on the 1T-TaS$ _2$ terminated surface layer with broken translational symmetry, but not on the 1T-TaS$ _2$ layers buried in the bulk. These results directly challenge the foundation of the current theoretical paradigm. On the 1T-TaS$ _2$ terminated surface layer, we further reveal a pseudogap and an anomalous doping effect. These phenomena and the dichotomy between surface and bulk layers also shed new light on the unusual coexistence of distinct electronic orders in this mysterious heterostructure.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
under review
Novel diamagnetic garnet-type substrate single crystals for ultralow-damping yttrium iron garnet Y3Fe5O12 films at cryogenic temperatures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
C. Guguschev, C. Dubs, R. Blukis, O. Surzhenko, M. Brützam, R. Koc, C. Rhode, K. Berger, C. Richter, C. Berryman, R. O. Serha, A. V. Chumak
Y3Sc2Ga3O12-Y3Sc2Al3O12 and Y3Sc2Ga3O12-Y3Al5O12 (YSGAG) solid solution single crystals with diameters up to 30 mm and total lengths up to about 100 mm were grown by the conventional Czochralski technique. Rocking curve measurements on polished sections revealed typical FWHM values of about 22 arcsec, which is indicative of relatively high structural quality for a solid-solution crystal. The grown substrate crystals are nearly lattice-matched with Y3Fe5O12 (YIG) to allow epitaxial growth of high-quality thin films. Single crystalline YIG films with thicknesses between 100 nanometer and 2.9 micrometer were successfully grown on epi-polished YSGAG substrates using liquid phase epitaxy (LPE). Selected magnetic and microwave properties of the epitaxial films, which still exhibit small lattice misfits to the substrates, were then studied at room temperature. In addition, initial low-temperature investigations confirm that the YIG/YSGAG system is superior to the conventional YIG/GGG (Gd3Ga5O12) system at temperatures below 10 K, as the ferromagnetic resonance (FMR) linewidth does not increase with decreasing temperature. Therefore, the novel diamagnetic substrates are better suited for microwave applications at low temperature, as excessive damping losses induced by paramagnetic substrates can be avoided. It therefore seems to be a suitable pathway to achieve scalable microwave components for hybrid-integrated quantum systems based on ultralow-damping YIG films that can operate efficiently at millikelvin temperatures.
Materials Science (cond-mat.mtrl-sci)
25 pages, 16 figures, 4 tables
Growth optimization of Ruddlesden-Popper nickelate high-temperature superconducting thin films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Wei Lv, Zihao Nie, Heng Wang, Haoliang Huang, Qikun Xue, Guangdi Zhou, Zhuoyu Chen
The discovery of ambient-pressure nickelate high-temperature superconductivity provides a new platform for probing the underlying superconducting mechanisms. However, the thermodynamic metastability of Ruddlesden-Popper nickelates Lnn+1NinO3n+1 (Ln = lanthanide) presents significant challenges in achieving precise control over their structure and oxygen stoichiometry. This study establishes a systematic approach for growing phase-pure, high-quality Ln3Ni2O7 thin films on LaAlO3 and SrLaAlO4 substrates using gigantic-oxidative atomic-layer-by-layer epitaxy. The films grown under an ultrastrong oxidizing ozone atmosphere are superconducting without further post annealing. Specifically, the optimal Ln3Ni2O7/SrLaAlO4 superconducting film exhibits an onset transition temperature (Tc,onset) of 50 K. Four critical factors governing the crystalline quality and superconducting properties of Ln3Ni2O7 films are identified: 1) precise cation stoichiometric control suppresses secondary phase formation; 2) complete atomic layer-by-layer coverage coupled with 3) optimized interface reconstruction minimizes stacking faults; 4) accurate oxygen content regulation is essential for achieving a single superconducting transition and high Tc,onset. These findings provide valuable insights for the layer-by-layer epitaxy growth of diverse oxide high-temperature superconducting films.
Superconductivity (cond-mat.supr-con)
Gapless Edge Gravitons and Quasiparticles in Fractional Quantum Hall Systems with Non-Local Confinement
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
Daniel Spasic-Mlacak, Nigel R. Cooper
One of the central tenets of the theory of the fractional quantum Hall effect is that the bulk quantized Hall response requires the existence of a gapless chiral edge mode. The field theoretical arguments for this rely on locality. While locality is typically met in standard experimental settings, it need not always apply. Motivated by experimental capabilities of photonic platforms, we study confining potentials that are step-like in angular momentum, and thus non-local in position. We show that this non-local potential does not host conventional chiral edge modes. These are replaced by gapless spin-2 edge states, which we show are connected to the collective ‘graviton’ excitations that are gapped in the bulk. Furthermore, we show that FQH states host gapless (charged) quasiparticles on their edges, even in the absence of conventional edge modes. The edge state energies vanish as a power-law in system size, with an exponent that characterises the bulk topological order.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Symmetry-induced magnetism in fullerene monolayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Jiaqi Wu, Leonard Werner Pingen, Bo Peng
Using molecular orbital theory, we introduce magnetism in pure-carbon, charge-neutral fullerene monolayers which are otherwise non-magnetic. By controlling either molecular or lattice symmetry, we can realise highly-tuneable magnetic fullerene monolayers. We demonstrate a general design principle based on group theory analysis and explain the origin of magnetism using two representative systems with $ S_4$ and $ C_3$ molecular symmetries. Moreover, for building blocks that lack appropriate molecular symmetry, we can enforce crystalline symmetry to induce magnetism as well. Finally, we discuss the experimental feasibility of realising our proposed magnetic fullerene monolayers by examining a previously synthesised C$ _{60}$ system. Our work opens a new direction in introducing magnetism in non-magnetic building blocks by enforcing either molecular or lattice symmetry.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Atomic and Molecular Clusters (physics.atm-clus), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Evaluating Moment Tensor Potential in Ag-Cu Alloy: Accuracy, Transferability, and Phase Diagram Fidelity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Mashroor S. Nitol, Marco J. Echeverría Iriarte, Doyl E. Dickel, Saryu J. Fensin
A Moment Tensor Potential (MTP) has been developed for the Cu-Ag binary alloy and its accuracy, transferability, and thermodynamic fidelity evaluated. The model was trained on a diverse dataset encompassing solid, liquid, and interfacial configurations derived from density functional theory (DFT) calculations. Benchmarking against experiment and DFT data demonstrated significant improvements over the widely used classical Embedded Atom Method (EAM) potential, particularly in predicting defect energetics, surface properties, and the eutectic phase diagram. Despite a slight underestimation of Ag’s melting point, the MTP model achieved consistent accuracy across elemental and binary systems without direct fitting to high-temperature phase transitions. The predicted eutectic temperature and composition were found in close agreement with experimental observations. These results establish MTP as a robust framework for modeling immiscible metallic systems and pave the way for its integration into large-scale atomistic simulations where both fidelity and generalizability are essential.
Materials Science (cond-mat.mtrl-sci)
Investigating the Electrical Transport Properties and Electronic Structure of Zr2CuSb3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Eoghan Downey, Soumya S. Bhat, Shane Smolenski, Ruiqi Tang, Carly Mistick, Aaron Bostwick, Chris Jozwiak, Eli Rotenberg, Demet Usanmaz, Na Hyun Jo
The checkerboard lattice has been proposed to host topological flat bands as a result of destructive interference among its various electronic hopping terms. However, it has proven challenging to realize experimentally due to the difficulty of isolating this structure from any significant out-of-plane bonding while maintaining structural integrity. Here, single crystals of Zr2CuSb3, a potential candidate for the checkerboard lattice, were synthesized using the solution (self-flux) method, and their structure was confirmed via X-ray diffraction. Electrical transport measurements indicate metallic behavior with electron-dominated carriers. Angle-resolved photoemission spectroscopy reveals multiple electron pockets and significant kz broadening due to its large c-axis and low dispersion features in k z. Density functional theory calculations further disentangle the contributions from each high-symmetry plane, providing a comprehensive characterization of electronic behavior.
Materials Science (cond-mat.mtrl-sci)
Asymmetric stress engineering of dense dislocations in brittle superconductors for strong vortex pinning
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-26 20:00 EDT
Meng Han, Chiheng Dong, Chao Yao, Zhihao Zhang, Qinghua Zhang, Yue Gong, He Huang, Dongliang Gong, Dongliang Wang, Xianping Zhang, Fang Liu, Yuping Sun, Zengwei Zhu, Jianqi Li, Junyi Luo, Satoshi Awaji, Xiaolin Wang, Jianxin Xie, Hideo Hosono, Yanwei Ma
Large lossless currents in high-temperature superconductors (HTS) critically rely on dense defects with suitable size and dimensionality to pin vortices, with dislocations being particularly effective due to their one-dimensional geometry to interact extensively with vortex lines. However, in non-metallic compounds such as HTS with rigid lattices, conventional deformation methods typically lead to catastrophic fracture rather than dislocation-mediated plasticity, making it a persistent challenge to introduce dislocations at high density. Here, we propose an asymmetric stress field strategy using extrusion to directly nucleate a high-density of dislocations in HTS by activating shear-driven lattice slip and twisting under superimposed hydrostatic compression. As demonstrated in iron-based superconductors (IBS), atomic displacements of nearly one angstrom trigger the formation of tilted dislocation lines with a density approaching that of metals. With further structural refinement, these dislocations serve as strong pinning centers that lead to a fivefold enhancement in the current-carrying capacity of IBS at 33 T, along with low anisotropy and a large irreversibility field. This work not only establishes a scalable route to engineer pinning landscapes in HTS, but also offers a generalizable framework for manipulating dislocation structures in rigid crystalline systems.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
27 pages, 5 figures
Adv. Mater. (2025): e13265
Optical Signatures of Band Flatness and Anisotropic Quantum Geometry in Magic-Angle Twisted Bilayer Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-26 20:00 EDT
We study the degree of band flatness and the anisotropic quantum geometry in magic-angle twisted bilayer graphene by varying the twist angle and the parameters of lattice relaxation using optical conductivity. We show that the degree of band flatness and its quantum geometry can be revealed through optical absorption and its resulting optical bounds, which are based on the trace condition in quantum geometry. More specifically, the narrow and isolated peak of optical absorption in the low-energy region provides information about the bandwidth of the two flat bands. When this value is smaller than the electron interaction, it serves as a critical condition for the emergence of flat band superconductivity. Furthermore, optical absorption also provides the gap value between the flat band and the dispersive band, and when this gap is larger than the electron interaction, it facilitates the realization of fractional Chern insulating phases. We show that the narrow and isolated peak of optical bound near zero energy decreases as lattice relaxation increases. Meanwhile, we demonstrate that the imaginary part of (generalized) optical Hall conductivity reveals the vanishing of the negative part of Berry curvature, which is enforced by the refined trace-determinant inequality. Accordingly, we show that the total amount of the negative part and component of the Berry curvature approaches zero in the single ideal flat-band case. In contrast, when considering all occupied bands, the total amount of the negative component is slightly different from zero. Lastly, we demonstrate that the vanishing of flat band velocity and the emergent chiral symmetry are sufficient conditions for the saturation of the trace condition, which pertains to the isotropic case. In contrast, the determinant condition can only be saturated in anisotropic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 6 figures
Broadband, Flexible, Skin-Compatible Carbon Dots/Graphene Photodetectors for Wearable Applications
New Submission | Other Condensed Matter (cond-mat.other) | 2025-08-26 20:00 EDT
Nouha Loudhaief, Petr Rozhin, Ilaria Bertuol, Ali Raza, Leonardo Viti, Subhankar Roy, Enrico Cavarzerani, Luca Sbuelz, Matteo Brilli, Andrea Serinolli, Jacopo Nicoletti, Riccardo Piccoli, Sebastián Castilla, Simone Dal Zilio, Miriam Serena Vitiello, Maurizio Selva, Flavio Rizzolio, Alvise Perosa, Giovanni Antonio Salvatore, Domenico De Fazio
The development of wearable photodetectors demands a unique combination of broadband optical sensitivity, mechanical flexibility, and skin-compatibility, with these requirements rarely met simultaneously by existing technologies. Here, we present photodetectors that combine all of these performances. This is achieved by integrating carbon dots, engineered for extended ultraviolet-to-near-infrared absorption, with single-layer graphene transferred onto a plastic substrate. Unlike traditional quantum dot systems, our carbon dots achieve a broad ultraviolet-to-near-infrared response without toxic heavy metals. Graphene provides an efficient channel for charge transport, while a biocompatible chitosan-glycerol electrolyte enables efficient, low-voltage carrier modulation, with peak performance at approximately 0.5 V gate bias. The resulting photodetectors exhibit a broadband photoresponse with responsivities of approximately 0.19 A/W at 406 nm, 0.32 A/W at 642 nm, and 0.18 A/W at 785 nm. They maintain consistent performance at a bending radius of 0.8 cm with negligible degradation after repeated cycles. Furthermore, skin-compatibility assessments using the SkinEthic model confirm the non-toxic nature and suitability of our devices for direct skin contact. The combination of broadband absorption (400-800 nm), flexibility, and skin-compatibility, along with low-voltage operation ($ <$ 1.5 V), positions our photodetectors as promising building blocks for next-generation wearable optoelectronics.
Other Condensed Matter (cond-mat.other)
Jerky chiral active particles
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-26 20:00 EDT
We introduce jerky chiral active Brownian particles (jcABPs), a generalization of conventional chiral active Brownian particles (cABPs) subjected to jerk, the time derivative of acceleration, and analytically derive their mean displacement and mean squared displacement (MSD). Our results show that jerk induces anomalous fluctuations and oscillatory behavior on the standard circular swimming of chiral active particles. The interplay of jerk, chirality and persistence produces a family of mean trajectories including damped and exploding Lissajous patterns alongside the well-known spira mirabilis (logarithmic spirals). Our work on jerky chiral active particles opens a new route to explore rich dynamical effects in active matter.
Statistical Mechanics (cond-mat.stat-mech)
18 pages, 8 figures
Geometry and dynamics of spring networks of spherical topology
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-26 20:00 EDT
The spring network model constitutes the backbone in the representations of a host of physical systems. In this work, we report the disturbance-driven microscopic dynamics of an isolated, closed spring network of spherical topology in mechanical equilibrium. The system permits self-intersection. We first show the lowest-energy configurations of the closed spring networks as packings of regular triangles. The dynamics of the disturbed spring network is analyzed from the multiple perspectives of energetics, structural instability, and speed distribution. We reveal the crumpling transition of strongly disturbed spring networks and the rapid convergence of the speed distribution toward the Maxwell-Boltzmann distribution. This work demonstrates the rich physics arising from the interplay of flexibility and dynamics. The results may yield insights into the shape fluctuation and structural instability of deformable membranes from the dynamical perspective.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Classical Physics (physics.class-ph), Computational Physics (physics.comp-ph)
11 pages, 6 figures
Phys. Rev. E 112, 025504 (2025)
Self-consistent dynamical Hubbard functional for correlated solids
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-26 20:00 EDT
Tommaso Chiarotti, Matteo Quinzi, Andrea Pintus, Mario Caserta, Andrea Ferretti, Nicola Marzari
Many-body functionals of the Green’s function can provide fundamental advances in electronic-structure calculations, due to their ability to accurately predict both spectral and thermodynamic properties, such as angle-resolved photoemission spectroscopy (ARPES) experiments and total energies of materials. However, fully first-principles, self-consistent calculations with these dynamical functionals remain a major challenge, ultimately limiting their application to thermodynamic quantities, and restricting spectral predictions to one-shot calculations. In this paper, we present a fully self-consistent treatment of the electronic structure of solids using a dynamical functional. Our approach leverages the so-called dynamical Hubbard functional, which generalizes the DFT+$ U$ correction by incorporating frequency-dependent screening, augmenting the static density functional to accurately describe both spectral and thermodynamic properties of materials with $ d$ - or $ f$ -localized orbitals near the Fermi level. To enable this, we employ the algorithmic-inversion method based on a sum-over-poles representation, resulting in a numerically accurate self-consistent scheme for frequency-integrated properties, while keeping real-axis spectral resolution for dynamically-resolved quantities. Using this framework, we study the paradigmatic correlated solid SrVO$ _3$ , accurately reproducing its spectral features, essentially confirming previous one-shot predictions, and improving the description of its equilibrium properties, such as the equilibrium volume and bulk modulus, bringing these significantly closer to experimental measurements.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Atomistic Structure of Transient Switching States in Ferroelectric AlScN
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-26 20:00 EDT
Jiawei Huang, Jinyang Li, Xinyue Guo, Tongqi Wen, David J. Srolovitz, Zhen Chen, Zuhuang Chen, Shi Liu
We resolve the microscopic mechanism of polarization switching in wurtzite ferroelectric AlScN by integrating advanced thin-film fabrication, ferroelectric switching dynamics characterizations, high-resolution scanning transmission electron microscopy (STEM), and large-scale molecular dynamics simulations enabled by a deep neural network-based interatomic potential. Contrary to earlier interpretations proposing a transient nonpolar intermediate phase, we demonstrate that the broad transitional regions previously observed in STEM images are projection artifacts resulting from the intrinsic three-dimensional zigzag morphology of 180$ ^\circ$ domain walls, which are a characteristic form of inversion domain boundary. This is further confirmed by STEM imaging of strategically prepared, partially switched Al$ _{0.75}$ Sc$ _{0.25}$ N thin films. Our simulations reveal that switching proceeds through collective, column-by-column atomic displacements, directly explaining the emergence of zigzag-shaped domain walls, and is consistent with the nucleation-limited switching behavior observed in experimental switching dynamic measurements. Furthermore, we show that increasing Sc content systematically lowers domain wall energy and associated nucleation barrier, thereby reducing the switching field in agreement with experimental trends. These findings establish a direct connection between local domain wall structure, switching kinetics, and macroscopic ferroelectric behavior.
Materials Science (cond-mat.mtrl-sci)