CMP Journal 2025-06-23
Statistics
Nature: 2
Nature Materials: 1
Nature Nanotechnology: 3
Nature Reviews Materials: 1
arXiv: 124
Nature
Modular arene functionalization by differential 1,2-diborylation
Original Paper | Homogeneous catalysis | 2025-06-22 20:00 EDT
Jingfeng Huo, Yue Fu, Melody J. Tang, Ya Su, Shengkun Hu, Peng Liu, Guangbin Dong
Aromatic rings, also known as arenes, containing two or more adjacent different substituents are ubiquitously found in small molecule drugs1. Strategies that can rapidly introduce diverse vicinal substituents to readily available precursors would greatly benefit generation of analogues of bioactive compounds2, which, however, remain challenging to realize to date. The existing approaches for preparing vicinal difunctionalized arenes lack modularity, or regioselectivity, or generality. Here we report a nickel-catalyzed vicinal diborylation method that can directly install two chemically differentiated boryl groups in a regio- and site-selective manner using readily available aryl triflates or chlorides as substrates. This reaction operates under simple and mild conditions and is scalable. It also shows a broad substrate scope and excellent functional group tolerance. Given that each boryl group can be independently transformed into various functional groups, this method offers a modular, regioselective, and divergent approach to access diverse vicinal difunctionalized arenes, showing promise for constructing analogue libraries. The combined experimental and computational mechanistic studies reveal a highly unusual reaction pathway, involving the formation of a dearomatized gem-diboryl species and 1,2-boron migration. The site- and regioselectivity of this reaction are proposed to be controlled by steric interactions of the boryl groups with the nickel catalyst. The mechanistic insights gained in this investigation could have broad implications on developing other boron-mediated functionalization reactions.
Homogeneous catalysis, Synthetic chemistry methodology
Gating and noelin clustering of native Ca2+-permeable AMPA receptors
Original Paper | Cryoelectron microscopy | 2025-06-22 20:00 EDT
Chengli Fang, Cathy J. Spangler, Jumi Park, Natalie Sheldon, Laurence O. Trussell, Eric Gouaux
AMPA-type ionotropic glutamate receptors (AMPARs) are integral to fast excitatory synaptic transmission and play vital roles in synaptic plasticity, motor coordination, learning, and memory1. While extensive structural studies have been conducted on recombinant AMPARs and native calcium impermeable (CI)-AMPARs alongside their auxiliary proteins2-5, the molecular architecture of native calcium permeable (CP)-AMPARs has remained undefined. To elucidate the subunit composition, physiological architecture, and gating mechanisms of CP-AMPARs, here we present the first visualization of these receptors, immunoaffinity purified from rat cerebella, and resolve their structures using cryo-electron microscopy (cryo-EM). Our results indicate that the predominant assembly consists of GluA1 and GluA4 subunits, with the GluA4 subunit occupying the B and D positions, while auxiliary subunits, including TARPs, are located at the B’/D’ positions and CNIHs or TARPs at the A’/C’ positions. Furthermore, we resolved the structure of the Noelin 1-GluA1/A4 complex, wherein Noelin 1 (Noe 1) specifically binds to the GluA4 subunit at the B and D positions. Notably, Noe 1 stabilizes the amino-terminal domain (ATD) layer without affecting receptor gating properties. Noe 1 contributes to AMPAR function by forming dimeric-AMPAR assemblies that likely engage in extracellular networks, clustering receptors within synaptic environments and modulating receptor responsiveness to synaptic inputs.
Cryoelectron microscopy, Ion channels in the nervous system, Synaptic transmission
Nature Materials
Sub-2-nm-droplet-driven growth of amorphous metal chalcogenides approaching the single-layer limit
Original Paper | Electrocatalysis | 2025-06-22 20:00 EDT
Zude Shi, Wen Qin, Zhili Hu, Mingyu Ma, Hong Liu, Zhiwen Shu, Yubing Jiang, Hang Xia, Wenyan Shi, Chao Yue Zhang, Xiaoru Sang, Cui Guo, Yunxin Li, Chengzhi Liu, Chengshi Gong, Hong Wang, Song Liu, Levente Tapasztó, Caitian Gao, Fucai Liu, Pengyi Tang, Yuan Liu, Huigao Duan, Erqing Xie, Zhuhua Zhang, Zheng Liu, Yongmin He
Atom-thin amorphous materials (for example, amorphous monolayer carbon) offer a designable material platform for fundamental studies of the disorder system, as well as the development of various applications. However, their growth at a single layer remains challenging since their thermodynamically favourable grains are neither two dimensional nor layered. Here we demonstrate the growth of 1-nm-thick, amorphous metal chalcogenides at a wafer scale using a nanodroplet-driven nanoribbon-to-film strategy. Metal clusters are initially liquified into 1-2 nm droplets at 120 °C, and they then orchestrate the growth of amorphous single-layer nanoribbons, which eventually merge into a continuous centimetre-scale film. Phase-field simulations, combined with our characterizations, suggest a non-equilibrium kinetic growth mechanism, which can be applicable to various films, for example, PtSex, IrSex, PdSex and RhSex. The synthesized films exhibit a range of unique properties, including tunable conductivity through disorder modulation, high work functions and remarkable catalytic activity, making them promising candidates for hole-injection contacts in p-type transistors and hydrogen production applications. This work opens a pathway for the synthesis of non-layered materials approaching the single-layer limit.
Electrocatalysis, Electronic devices, Glasses, Two-dimensional materials
Nature Nanotechnology
Tailoring the adjuvanticity of lipid nanoparticles by PEG lipid ratio and phospholipid modifications
Original Paper | Drug delivery | 2025-06-22 20:00 EDT
Máté Vadovics, Wenchen Zhao, Emily F. Daley, Kieu Lam, Owen Daly, Khalid Rashid, Hailey R. Lee, Petra Schreiner, Kendall A. Lundgreen, Brian T. Gaudette, Vladimir V. Shuvaev, Evguenia Arguiri, Hiromi Muramatsu, András Sárközy, Thandiswa Mdluli, Junchao Xu, Xuexiang Han, Nina De Luna, Diana Castaño, Emily Bettini, Edit Ábrahám, Zoltan Lipinszki, Giuseppe Carlucci, Avinash Haridas Bansode, Katelyn Nguyen, Thuc M. Le, Tony Luu, Vladimir R. Muzykantov, Paul Bates, David Allman, Michael J. Mitchell, Michela Locci, Caius G. Radu, James Heyes, Norbert Pardi
Lipid nanoparticles (LNPs) represent the leading delivery platform for mRNA vaccines with advantageous biocompatibility, scalability, adjuvant activity and often an acceptable safety profile. Here we investigate the physicochemical characteristics and adjuvanticity of four-component LNPs. Previous vaccine studies have demonstrated that altering the ionizable lipid influences the adjuvanticity of an LNP; however, the impact of the polyethylene glycol lipid and phospholipid has received less attention. Our mRNA-LNP vaccine formulations utilized different phospholipids and varying ratios of polyethylene glycol lipid, whereas the ionizable lipid and cholesterol remained approximately constant. We demonstrate that such modifications impact the magnitude and quality of the vaccine-elicited immune responses. We also dissect the underlying mechanisms and show that the biodistribution and cellular uptake of LNPs correlate with the magnitude and quality of the immune responses. These findings support the rational design of novel LNPs to tailor immune responses (cellular or humoral focused) based on the vaccine application.
Drug delivery, Virology
Nonlinear Nernst effect in trilayer graphene at zero magnetic field
Original Paper | Electronic properties and devices | 2025-06-22 20:00 EDT
Hao Liu, Jingru Li, Zhifan Zhang, Jinfeng Zhai, Min Zhang, Hua Jiang, X. C. Xie, Pan He, Jian Shen
The Nernst effect, that is, the generation of a transverse voltage in response to a temperature gradient, enables thermoelectric energy conversion. In the absence of an external magnetic field, the linear Nernst effect is forbidden in non-magnetic materials because of time-reversal symmetry constraints, but the recently predicted nonlinear Nernst effect (NNE) is allowed. Here we report the experimental observation of the NNE in non-magnetic ABA trilayer graphene, even in the absence of an external magnetic field. This effect is detected via electric harmonic measurements under an alternating temperature gradient at temperatures below 12 K. The NNE exhibits a quadratic dependence on the temperature gradient. It is notably enhanced near the charge neutrality point and reaches a giant effective Nernst coefficient of up to 300 µV K-1 at 2 K, surpassing the linear coefficients of magnetic materials. Moreover, we establish a scaling law between the NNE and the linear Seebeck effect, confirming the dominance of a skew scattering mechanism in driving the NNE. Our findings demonstrate an alternative approach for thermoelectric energy harvesting and cooling applications via nonlinear thermoelectric responses, which may, in the long run, offer alternative approaches towards the development of advanced thermoelectric devices.
Electronic properties and devices, Electronic properties and materials
Mesoscale dynamics of electrosorbed ions in fast-charging carbon-based nanoporous electrodes
Original Paper | Electrochemistry | 2025-06-22 20:00 EDT
Peiyao Wang, Ke Zhang, Jinsha Liao, Xiao Wang, George P. Simon, Jefferson Zhe Liu, Dan Li
Electrosorption, the accumulation of electrolyte ions at charged interfaces, is a common phenomenon across various electrochemical systems. Its impact is particularly pronounced in nanoporous electrodes owing to their high surface-to-volume ratios. Although electrosorption alters the ion distribution at the electrode-electrolyte interface through the formation of an electrical double layer, the effects of electrosorbed ions on the charge storage dynamics in nanoporous electrodes and their ability to improve charging processes have often been overlooked. Here we use a multilayered reduced graphene oxide-based membrane as a model nanoporous electrode material, integrating numerical simulations with experimental insights. We monitor the spatiotemporal distribution of electrosorbed ions and electrical potentials across the nanopore network during fast charging of symmetrical laboratory-scale cells using aqueous and non-aqueous electrolyte solutions. This method allowed us to quantitatively assess how features of the nanoporous electrode mesostructure, such as nanoslit size, the distribution of nanoslit sizes and electrode thickness, dynamically influence ion electrosorption and the local electrical and chemical potentials across the network. Our findings reveal that the mesostructure of nanoporous electrodes influences how migration and diffusion currents, mediated by electrosorbed ions, respond to charging rates.
Electrochemistry, Porous materials, Structural properties, Supercapacitors, Theoretical chemistry
Nature Reviews Materials
Materials design and integration strategies for soft bioelectronics in digital healthcare
Review Paper | Biomedical materials | 2025-06-22 20:00 EDT
Hye Jin Kim, Ja Hoon Koo, Seunghwan Lee, Taeghwan Hyeon, Dae-Hyeong Kim
Advancements in bioelectronics are revolutionizing traditional healthcare by shifting the focus from in-hospital disease diagnosis and treatment to at-home continuous preventive care. This transformation integrates real-time health monitoring and point-of-care interventional therapies and enables artificial intelligence-based health management strategies. However, the mechanical mismatch between rigid bioelectronic devices and soft biological tissues presents important challenges, particularly in long-term applications, including poor adhesion, tissue degeneration, high noise level, signal interference and device instability. To address these challenges, soft bioelectronics – leveraging high-performance, tissue-mimicking and mechanically soft materials – has emerged as a disruptive solution. This Review highlights advancements in materials design and system-level integration strategies for soft bioelectronics, driving the development of next-generation digital healthcare technologies. We categorize materials design approaches, introduce fabrication techniques for soft bioelectronics and explore integration methods. Furthermore, we showcase applications of wearable and implantable soft bioelectronics, demonstrating their potential for continuous health monitoring and therapeutic interventions, ultimately enabling closed-loop health management.
Biomedical materials, Drug delivery, Implants, Nanoscience and technology
arXiv
On the theory of supermodulation of the superconducting order parameter by supermodulation of the apex distance in optimally doped Bi$_2$Sr$_2$CaCu$2$O${8+x}$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Albert M. Varonov, Todor M. Mishonov
Recently using Scanning Josephson Tunneling Microscopy (SJTM) in the group of Séamus Davis a super-modulation of the superconducting order parameter induced by super-modulation of the distance $ \delta$ between planar Cu and apical O was observed in [O’Mahony et al, On the electron pairing mechanism of copper-oxide high temperature superconductivity, PNAS Vol. 119(37), e2207449119 (2022)]. The authors conclude: “concurrence of prediction from strong correlation theory… with these observations indicates that… super-exchange is the electron pairing mechanism of Bi$ 2$ Sr$ 2$ CaCu$ 2$ O$ {8+x}$ .” Additionally, the charge transfer energy $ \mathcal{E}$ , probably between O2$ p_z$ and Cu$ 3d{x^2-y^2}$ levels was studied by SJTM, too. In our current theoretical study we use LCAO approximation and Hilbert space spanned on 5 atomic orbitals: Cu$ 4s$ , Cu$ 3d{x^2-y^2}$ , O2$ p_x$ , O2$ p_y$ , O2$ p_z$ . For the only super-exchange amplitude $ J{sd}$ we use the Kondo double electron exchange between Cu$ 4s$ and Cu$ 3d{x^2-y^2}$ orbitals and its anti-ferromagnetic sign is determined by adjacent to the copper ion in-plane oxygen orbitals. Within this approximations we have calculated: “Measured dependence of… electron-pair density $ n_p$ on the displacement $ \delta$ of the apical O atoms from the planar Cu atoms” on [O’Mahony et al., Fig. 5C] and obtained an excellent accuracy. We discuss that the correlation between the shape of Fermi contour and the critical temperature of optimally hole-doped cuprates can be considered as an analogue of the isotope effect of phonon superconductors. The analyzed SJTM experiment is one of the best confirmations of the [J. Röhler, Plane dimpling and Cu4s hybridization in YBa$ _2$ Cu$ _3$ O$ _{7-x}$ , Physica B: Cond. Matt. Vol. 284-288, 1041 (2000)] idea that the hybridization of Cu$ 4s$ with conduction band leads to increasing of $ T_c$ .
Superconductivity (cond-mat.supr-con)
7 pages, 2 figures, 1 table, 29 refs
Thermodynamics and Legendre Duality in Optimal Networks
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Amilcare Porporato, Shashank Kumar Anand, Salvatore Calabrese, Luca Ridolfi, Lamberto Rondoni
Optimality principles in nonequilibrium transport networks are linked to a thermodynamic formalism based on generalized transport potentials endowed with Legendre duality and related contact structure. This allows quantifying the distance from non-equilibrium operating points, analogously to thermodynamic availability as well as to shed light on optimality principles in relation to different imposed constraints. Extremizations of generalized dissipation and entropy production appear as special cases that require power-law resistances and – for entropy production – also isothermal conditions. Changes in stability of multiple operating points are interpreted as phase transitions based on non-equilibrium equations of state, while cost-based optimization of transport properties reveals connections to the generalized dissipation in the case of power law costs and linear resistance law, but now with typically unstable operating points which give rise to branched optimal transport.
Statistical Mechanics (cond-mat.stat-mech), Adaptation and Self-Organizing Systems (nlin.AO), Applied Physics (physics.app-ph)
Two Types of Temporal Symmetry in the Laws of Nature
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
This work explores the implications of assuming time symmetry and applying bridge-type, time-symmetric temporal boundary conditions to deterministic laws of nature with random components. The analysis, drawing on the works of Kolmogorov and Anderson, leads to two forms of governing equations, referred to here as symmetric and antisymmetric. These equations account for the emergence of characteristics associated with conventional thermodynamics, the arrow of time, and a form of antecedent causality. The directional properties of time arise from the mathematical structure of Markov bridges, without requiring any postulates that impose a preferred direction of time.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
22 pages 2 figures
Entropy 2025, 27(5), 466
Breakdown of the thermodynamic limit in quantum spin and dimer models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Jeet Shah, Laura Shou, Jeremy Shuler, Victor Galitski
The thermodynamic limit is foundational to statistical mechanics, underlying our understanding of many-body phases. It assumes that, as the system size grows infinitely at fixed density of particles, unambiguous macroscopic phases emerge that are independent of the system’s boundary shape. We present explicit quantum spin and dimer Hamiltonians whose ground states violate this principle. Our construction relies on the previous mathematical work on classical dimers on the Aztec diamond and the square-octagon fortress, where geometry-dependent phase behaviors are observed in the infinite-size limit. We reverse engineer quantum spin Hamiltonians on the square and the square-octagon lattices whose ground states at the Rokhsar-Kivelson points are described by classical dimer coverings. On diamond-shaped domains, we find macroscopic boundary regions exhibiting distinct quantum phases from those on square-shaped domains. We study the nature of these phases by calculating the dimer-dimer and vison correlators and adapt Kasteleyn matrix based analytical and numerical methods for computing the vison correlator, which are significantly more efficient than standard Monte Carlo techniques. Our results show that the square-octagon lattice supports a single gapped short-range entangled phase, with exponentially decaying dimer correlators and a constant vison correlator. When the same model is considered on a diamond-shaped domain, an additional ordered phase emerges near the corners, where the dimers are in a staggered pattern.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
23 + 6 pages, 20 + 2 figures
Probing the pseudogap and beyond: examining single-particle properties of the hole- and electron-doped Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Wen O. Wang, Edwin W. Huang, Brian Moritz, Thomas P. Devereaux
We compute high-resolution angle-resolved photoemission spectroscopy of the Hubbard model using the unbiased determinant quantum Monte Carlo algorithm, revealing an asymmetry between electron and hole doping. Electron doping exhibits more coherent quasiparticles and stronger antiferromagnetic correlations compared to hole doping. At low doping, a nodal-antinodal dichotomy on the Fermi surface is observed, similar to cuprate experiments. The dichotomy reflects the momentum dependence of the Mott gap, as manifested in both the spectral function and the self-energy. For hole doping, we observe a transition towards the pseudogap, without signature of pocket formation. The simulated nuclear magnetic resonance pseudogap temperatures do not necessarily agree with the temperature determined by spectroscopy. These findings collectively suggest the pseudogap is a smooth crossover driven by strong correlations.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
16 pages, 14 figures. Appendix: 9 pages, 11 figures
Inhibition of whisker growth by crafting more decomposition-resistant Ti2SnC MAX phase through vanadium solid solution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Haifeng Tang, Xiaodan Yin, Peigen Zhang, Victor Karpov, Vamsi Borra, Zhihua Tian, Wei Zheng, Jianxiang Ding, ZhengMing Sun
The exceptional synergy of ceramic and metallic properties within MAX phases positions them as highly promising for a wide array of applications. However, their stability has been threatened by the phenomenon of A-site metal whisker growth. Herein, we have significantly mitigated tin whisker growth in Ti2SnC by incorporating vanadium solutes at its M-site. With an increase in vanadium concentration, there is a marked reduction in the degree of decomposition of the M-site solid solution when subjected to the same level of externally destructive treatments, thereby inhibiting whisker proliferation. Both experimental outcomes and theoretical calculations reveal that the vanadium solid solution augments the hardness, Pughs ratio, and Poissons ratio of Ti2SnC, enhancing its mechanical strength and toughness. The incorporation of V atoms introduces stronger V C and V Sn bonds, as evidenced by its electronic density of states and bulk modulus, thus significantly bolstering the resistance of MAX phases against decomposition and effectively curtailing whisker growth. Additionally, the phenomenon reported in this paper also conforms to the electrostatic theory of whisker growth. This work for the first time achieves the suppression of A-site whisker growth through an M-site solid solution, thereby extending their potential for applications where durability and reliability are paramount.
Materials Science (cond-mat.mtrl-sci)
20 Pages
Mean first passage time of active Brownian particles in two dimensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Sarafa A. Iyaniwura, Zhiwei Peng
The mean first passage time (MFPT) is a key metric for understanding transport, search, and escape processes in stochastic systems. While well characterized for passive Brownian particles, its behavior in active systems-such as active Brownian particles (ABPs)-remains less understood due to their self-propelled, nonequilibrium dynamics. In this paper, we formulate and analyze an elliptic partial differential equation (PDE) to characterize the MFPT of ABPs in two-dimensional domains, including circular, annular, and elliptical regions. For annular regions, we analyze the MFPT of ABPs under various boundary conditions. Our results reveal rich behaviors in the MFPT of ABPs that differ fundamentally from those of passive particles. Notably, the MFPT exhibits non-monotonic dependence on the initial position and orientation of the particle, with maxima often occurring away from the domain center. We also find that increasing swimming speed can either increase or decrease the MFPT depending on the geometry and initial orientation. Asymptotic analysis of the PDE in the weak-activity regime provides insight into how activity modifies escape statistics of the particles in different geometries. Finally, our numerical solutions of the PDE are validated against Monte Carlo simulations.
Soft Condensed Matter (cond-mat.soft)
First-Principles Thermodynamics of Al$_{10}$V: An Analytical Treatment of Localized Anharmonic Modes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Hassan Y. Albuhairan, Marek Mihalkovič, Michael Widom
Many complex intermetallic structures possess cage-like environments that can host additional guest atoms. In Al$ _{10}$ V, these atoms give rise to low-frequency, localized vibrations (Einstein modes) that dominate the thermodynamic response at low temperature. They become imaginary under volume expansion as temperature rises, invalidating the harmonic approximation. We develop a framework to incorporate these strongly anharmonic vibrational modes into first-principles thermodynamic calculations. By explicitly modeling the cage potential and solving the associated Schrödinger equation numerically, we compute the full anharmonic free energy contribution and demonstrate its impact on thermodynamic phase stability. Our results reproduce key experimental signatures, including the anomalous rise in the thermal expansion coefficient and specific heat at low temperatures, and reveal that the presence of guest atoms is essential to stabilizing the Al$ _{10}$ V phase at elevated temperatures.
Materials Science (cond-mat.mtrl-sci)
Generalized Spectral Statistics in the Kicked Ising model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
The kicked Ising model has been studied extensively as a model of quantum chaos. Bertini, Kos, and Prosen studied the system in the thermodynamic limit, finding an analytic expression for the spectral form factor, $ K(t)$ , at the self-dual point with periodic boundary conditions. The spectral form factor is the 2nd moment of the trace of the time evolution operator, and we study the higher moments of this random variable in the kicked Ising model. A previous study of these higher moments by Flack, Bertini, and Prosen showed that, surprisingly, the trace behaves like a real Gaussian random variable when the system has periodic boundary conditions at the self dual point. By contrast, we investigate the model with open boundary conditions at the self dual point and find that the trace of the time evolution operator behaves as a complex Gaussian random variable as expected from random matrix universality based on the circular orthogonal ensemble. This result highlights a surprisingly strong effect of boundary conditions on the statistics of the trace. We also study a generalization of the spectral form factor known as the Loschmidt spectral form factor and present results for different boundary conditions.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Chaotic Dynamics (nlin.CD), Quantum Physics (quant-ph)
23 pages. Watch a 4-minute video abstract at this https URL
Mean-field theory of the electromagnon resonance
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Pavel A. Andreev, Mariya Iv. Trukhanova
We present the analytical theory of the electromagnon resonance for the multiferroics of spin origin. We consider the spin density evolution under the influence of magnetoelectric coupling in the presence of the electromagnetic wave. The dielectric permeability is found for the eigen-wave perturbations accompanied by perturbations of the electric field. The imaginary part of the dielectric permeability is found as the function of the applied electric field frequency, while the frequency of the eigen-waves is found from the dispersion equation as the function of the wave vector and parameters of the system. The result shows the existence of two peaks. One sharp peak is associated with the magnon resonance, while the second wide peak at the approximately four times smaller frequency is interpreted as the electromagnon resonance in accordance with existing experimental data.
Materials Science (cond-mat.mtrl-sci)
5 pages, 1 figure, 6 pages of Supplementary materials
A new Surrogate Microstructure Generator for Porous Materials with Applications to the Buffer Layer of TRISO Nuclear Fuel Particles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Philipp Eisenhardt, Ustim Khristenko, Barbara Wohlmuth, Andrei Constantinescu
We present a surrogate material model for generating microstructure samples reproducing the morphology of the real material. The generator is based on Gaussian random fields, with a Matérn kernel and a topological support field defined through ellipsoidal inclusions clustered by a random walk algorithm. We identify the surrogate model parameters by minimizing misfits in a list of statistical and geometrical descriptors of the material microstructure. To demonstrate the effectiveness of the method for porous nuclear materials, we apply the generator to the buffer layer of Tristructural Isotropic Nuclear Fuel (TRISO) particles. This part has been shown to be failure sensitive part of TRISO nuclear fuel and our generator is optimized with respect to a dataset of FIB-SEM tomography across the buffer layer thickness. We evaluate the performance by applying mechanical modeling with problems of linear elastic homogenization and linear elastic brittle fracture material properties and comparing the behaviour of the dataset microstructure and the surrogate microstructure. This shows good agreement between the dataset microstructure and the generated microstructures over a large range of porosities.
Materials Science (cond-mat.mtrl-sci)
33 pages
Characterizing Spin-Orbit Torques by Tensorial Spin Hall Magnetoresistance
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Magnetoresistance (MR) provides a crucial tool for experimentally studying spin torques. While MR is well established in the device geometry of the spin Hall effect (SHE), as exemplified by the magnet/heavy-metal heterostructures, its role and manifestation beyond the SHE paradigm remain elusive. Here we propose a previously unknown form of MR where the underlying charge-to-spin conversion and its inverse process violate the simple geometry of the SHE, calling for tensorial descriptions. This novel MR can generate a series of unique harmonic responses essential for the experimental characterization of unconventional spin-orbit torques in non-SHE materials. Our results are demonstrated in semimetal WTe$ _2$ thin films.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Unveiling defect motifs in amorphous GeSe using machine learning interatomic potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Minseok Moon, Seungwoo Hwang, Jaesun Kim, Yutack Park, Changho Hong, Seungwu Han
Ovonic threshold switching (OTS) selectors play a critical role in non-volatile memory devices because of their nonlinear electrical behavior and polarity-dependent threshold voltages. However, the atomic-scale origins of the defect states responsible for these properties are not yet fully understood. In this study, we use molecular dynamics simulations accelerated by machine-learning interatomic potentials to investigate defects in amorphous GeSe. We begin by benchmarking several potential architectures-including descriptor-based models and graph neural network (GNN) models-and show that faithfully representing amorphous GeSe requires capturing higher-order interactions (at least four-body correlations) and medium-range structural order. We find that GNN architectures with multiple interaction layers successfully capture these correlations and structural motifs, preventing the spurious defects that less expressive models introduce. With our optimized GNN potential, we examine twenty independent 960-atom amorphous GeSe structures and identify two distinct defect motifs: aligned Ge chains, which give rise to defect states near the conduction band, and overcoordinated Ge chains, which produce defect states near the valence band. We further correlate these electronic defect levels with specific structural features-namely, the average alignment of bond angles in the aligned chains and the degree of local Peierls distortion around overcoordinated Ge atoms. These findings provide a theoretical framework for interpreting experimental observations and deepen our understanding of defect-driven OTS phenomena in amorphous GeSe.
Materials Science (cond-mat.mtrl-sci)
21 pages, 11 figures, Supplementary information included as ancillary file (+12 pages)
$La_3Pd_2NaO_9$: A High-Valent Insulating Palladate
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Qingqing Yang, Ning Guo, Tieyan Chang, Zheng Guo, Xiaoli Wang, Chuanyan Fan, Chao Liu, Lu Han, Feiyu Li, Tao He, Qiang Zheng, Yu-Sheng Chen, Junjie Zhang
A high-valent palladate, $ La_3Pd_2NaO_9$ , has been synthesized for the first time. Single crystals with dimensions of 20 $ {\mu}$ m on edge were successfully grown using the flux method at 420 $ ^o$ C and 70 bar oxygen pressure. Energy dispersive spectroscopy (EDS) and inductively coupled plasma mass spectroscopy (ICP) measurements show that the atomic ratio of La: (Pd+Na) is 3: 3 and Pd: Na is 2: 1. X-ray photoelectron spectroscopy (XPS) measurements show that the oxidation state of Pd is dominated by +4. Synchrotron X-ray single-crystal diffraction measurements revealed that this material crystallizes in the monoclinic $ P2_1/c$ space group with charge ordering of Na and Pd. Real-space imaging via scanning transmission electron microscopy (STEM) confirmed the crystal structure and revealed excellent sample homogeneity. Electrical resistivity measurements show an insulating behavior. Magnetic measurements show an unexpected paramagnetic behavior, which probably originate from a small fraction of high-spin Pd$ ^{2+}$ evidenced by XPS. The successful growth of $ La_3Pd_2NaO_9$ single crystals with a high-valent oxidation state of Pd offers an approach for exploring interesting palladates, including potential bilayer Ruddlesden-Popper palladates analogous to the high temperature superconducting $ La_3Ni_2O_7$ .
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
19 pages, 8 figures. This document is the unedited author’s version of a Submitted Work that was subsequently accepted for publication in Inorganic Chemistry, copyright American Chemical Society after peer review. To access the final edited and published work, a link will be provided soon
Unifying renormalized and bare viscosity in two-dimensional molecular dynamics simulations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Kazuma Yokota, Masato Itami, Shin-ichi Sasa
Fluctuating hydrodynamics provides a framework connecting mesoscopic fluctuations with macroscopic transport behavior. To bridge mesoscopic and macroscopic transport from microscopic dynamics, we introduce a wavenumber-dependent viscosity, defined via the equilibrium correlation of time-averaged Fourier components of the fine-grained shear stress field, as a finite-wavevector extension of the Green–Kubo formula. Two-dimensional molecular dynamics simulations reveal its small-wavenumber divergence characteristic of the renormalized viscosity, while its large-wavenumber behavior determines the bare viscosity, thereby establishing a link between mesoscopic and macroscopic transport based on microscopic dynamics.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 7 figures
Anti-Sisyphus driving in a matter-wave swing
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Wen L. Liu, Jun Jian, Ning X. Zheng, Hui Tang, Ji Z. Wu, Yu Q. Li, Wen X. Zhang, Jie Ma, Suo T. Jia
Dilute-gas Bose-Einstein condensates are an exceptionally versatile testbed for the investigation of physics phenomenon especially the well-known classical system. Here we use a degenerate Bose gas of sodium atoms confined in an optical dipole trap to simulate the matter-wave on the swing. Under the driving of Anti-Sisyphus process, the swing was excited successfully. Moreover, the spin echo like behavior and collective-mode excitation appear during the oscillation of matter-wave swing, manifesting the quantum nature of the system beyond its classical counterpart. Our work lays the foundation for matter-wave on the swing and more generally points to a future of practical applications for the motional quantum states linked with quantum information science.
Quantum Gases (cond-mat.quant-gas)
Exceedingly large in-plane critical field of finite-momentum pairing state in bulk superlattices
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Junfa Lin, Ziqiao Wang, Hongyi Yan, Xiaoping Ma, Zihan Cui, Yu Zhang, Yuxuan Lei, Jie Liu, Rao Li, Chuanying Xi, Zengwei Zhu, Huakun Zuo, Yanzhao Liu, Huaixin Yang, Tian-Long Xia, Haiwen Liu, Yi Liu, Jian Wang
Magnetic flux profoundly influences the phase factor of charge particles, leading to exotic quantum phenomena. A recent example is that the orbital effect of magnetic field could induce finite-momentum pairing state in nanoflakes, which offers a new pathway to realize the spatially modulated superconductivity distinct from the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state induced by Zeeman effect. However, whether such intriguing state can exist in the bulk materials under extremely large magnetic field remains elusive. Here we report the orbital effect induced finite-momentum pairing state with exceedingly large in-plane critical field in a bulk superconducting superlattice. Remarkably, the in-plane critical field shows a pronounced upturn behavior, exceeding eight times the Pauli limit which is comparable to monolayer Ising superconductor. Under high in-plane magnetic fields, significant anisotropic transport behavior between the interlayer and intralayer directions is detected, highlighting the critical role of suppressed interlayer coherence in the orbital effect induced finite-momentum pairing state. Crucially, this finite-momentum pairing state remains robust against moderate disorder. Our findings suggest that van der Waals superlattices, with strong Ising spin-orbit coupling and tunable interlayer coherence, offer new avenues for constructing and modulating unconventional superconducting states.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Band engineering aided by topological edge state proximity effects: Inducing anti-chirality in graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Ricardo Y. Díaz-Bonifaz, Carlos Ramírez
In this work we analyze infinite graphene nanoribbons subjected to non-uniform magnetic fields that produce topological domain walls in the quantum Hall regime. We show how the proximity between edge states from neighboring domains modifies the band structure due to the state coupling near the domain walls. The proximity-induced band deformations produce phenomena such as bulk-like dispersion that coexist with Landau levels and valley-polarized current paths. It is shown that edge state coupling can be enhanced by continuously varying the magnetic field between two non-trivial topological phases. The mechanism by which neighboring edge states modify the band structure is addressed by tracking their wave-functions over isolated bands and by analyzing the magnetic confinement potential near the domain wall. By calculating the local current density, we show that the coexistence of topological edge states with bulk-like dispersion can lead to the appearance of anti-chirality, in which co-propagating currents appear in the edges while the rest of the nanoribbon is occupied with bulk states. The appearance of anti-chirality is justified by comparing the proposed non-uniform magnetic field profile with an anti-chiral modified Haldane model.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
22 pages, 9 figures
Ultrafast dynamics of three-dimensional Kane plasmons in the narrow-bandgap Hg${0.8}$Cd${0.2}$Te
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Xiaoyue Zhou, Yi Chan, Siyuan Zhu, Fu Deng, Wei Bai, Jingdi Zhang
We report on an ultrafast terahertz spectroscopic study on the dynamics of free carriers and the pertinent bulk plasmons in Hg$ _{0.8}$ Cd$ _{0.2}$ Te (MCT) film, a narrowband semiconductor accommodating three dimensional massless Kane fermions. The ultrabroadband terahertz source enables the investigation of the lightly doped equilibrium state in the presence of plasmon-phonon hybridization through the heavily doped excited state, primarily dominated by plasmons. Without the recourse to the resource consuming cryogenic high magnetic field spectroscopy that hinges on observable related to the interband transition, we show that the massless band dispersion can instead be conveniently perceived by the room temperature study of the intraband transition through the determination of the plasmon carrier density relationship. We found the plasma frequency in MCT scales with the cube root of carrier density, in contrast with the square root scaling in the conventional massive fermion system of parabolic band dispersion. This work also answers the curious question of whether the MCT can maintain its massless Kane fermion character in case the strict gapless condition is deviated from. The method presented herein provides a convenient approach to identifying the landscape of both massless and massive band dispersion.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Shift current in 2D Janus Transition-Metal Dichalcogenides: the role of excitons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Yuncheng Mao, Ju Zhou, Myrta Grüning, Claudio Attaccalite
We study the shift current in two two-dimensional (2D) Janus transition metal dichalcogenides: molybdenum diselenide (MoSSe) and tungsten diselenide (WSSe). The shift current is evaluated using a real-time approach, in which the coupling with an external field is described in terms of a dynamical Berry phase. This approach incorporates electron-hole interactions and quasiparticle band structure renormalization through an effective Hamiltonian derived from many-body perturbation theory. We find that the shift current is strongly enhanced in correspondence of C excitons. An analysis in terms of the electron-hole pairs reveals that electron and hole are localized on different atoms, and thus following an optical excitation, the center of the electron charge is shifted thus giving rise to a significant photocurrent. These results highlight the role played by excitons in the shift-current response of Janus TMDs and demonstrate that these materials are promising building blocks for future photovoltaic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Superfluid dome in the spatially modulated two-dimensional XY model
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Feng-Feng Song, Aditya Chugh, Hanggai Nuomin, Naoki Kawashima, Alexander Wietek
In strongly correlated electron systems, superconductivity and charge density waves often coexist in close proximity, suggesting a deeper relationship between these competing phases. Recent research indicates that these orders can intertwine, with the superconducting order parameter coupling to modulations in the electronic density. To elucidate this interplay, we study a two-dimensional XY model with a periodic modulation of the coupling strength in one spatial direction. Using a combination of tensor network methods and Monte Carlo simulations, we reveal a non-monotonic, dome-like dependence of $ T_c$ on the modulation wavelength, with the peak $ T_c$ shifting to longer wavelengths as the modulation strength grows. The origin of this phenomenon is traced back to an effective pinning of vortices in the valleys of the modulation, confirmed by a comparison to modulated $ q$ -state clock models. These findings shed new light on the phase behavior of intertwined superconducting and charge-ordered states, offering a deeper understanding of their complex interactions.
Superconductivity (cond-mat.supr-con), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 5 figures + 14 pages, 9 figures
Microstates : Do the outliers worth
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
This note addresses the relevance of rare events in system dynamics, inspired by Jill North reflections on the origin of the arrow of time in thermodynamics. After identifying the existence of rare events, characterized by a Pareto distribution, within a simple gas particle simulation, we investigate their impact on entropy evolution. These rare events are associated with microstates that locally decrease entropy, in contrast to the overall entropy increase observed in the bulk of the system. We present numerical simulations of gas particles, both without and with a gravity-like attractive force, to explore the fate of these rare events. Our results show that, while rare events can transiently generate local decreases in entropy, global entropy may continue to increase in accordance with the second law of thermodynamics. The introduction of gravity-like attraction stabilizes these low-entropy configurations, allowing them to persist longer. This study highlights the interplay between rare statistical fluctuations and macroscopic thermodynamic behavior, providing new insights into the emergence and stability of order in complex systems.
Statistical Mechanics (cond-mat.stat-mech), History and Philosophy of Physics (physics.hist-ph)
8 pages, 6 figures, short note
Finite Thickness Effects on Metallization Vs. Chiral Majorana Fermions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Xin Yue, Guo-Jian Qiao, C. P. Sun
In heterostructures composed of quantum anomalous Hall insulators and \textit{s}-wave superconductors (SCs), metallization hinders the identification of chiral Majorana fermions (CMFs). In this Letter, we study how the thickness of SC affects the competition between metallization and CMFs by a holistic approach previously developed for hybrid nanowire systems [Phys. Rev. Lett. 133, 266605 (2024)]. We predict three types of structures that vary with thickness of SC: (i) Periodic structure of metallization. For thin SCs ($ \sim$ 10,nm), the metallization region exhibits oscillations as the thickness of SC changes, with the oscillation period corresponding to the Fermi wavelength of SC. (ii) Periodic structure of CMFs. For intermediate thicknesses ($ \sim$ 100,nm), the window width for observing CMFs exhibits a periodic behavior, oscillating with the same period. (iii) Stable structure of CMFs. For thick SCs ($ \sim$ 1000,nm), the behavior of CMFs becomes uniform as the thickness varies. Optimizing the thickness of SC may thus improve data quality and provide clearer evidence for CMFs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Coherent Spin Waves in Curved Ferromagnetic Nanocaps of a 3D-printed Magnonic Crystal
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Huixin Guo, Kilian Lenz, Mateusz Gołębiewski, Ryszard Narkowicz, Jürgen Lindner, Maciej Krawczyk, Dirk Grundler
Coherent magnon modes in a truly three-dimensional (3D) magnonic crystal have not yet been investigated. This scientific gap exists despite the numerous theoretical predictions about miniband formation and edge modes with topological protection. Such properties are key to advance nanomagnonics for ultrafast data processing. In this work, we use a scalable nanotechnology and integrate a 3D magnonic crystal to an on-chip microresonator. It was fabricated by two-photon lithography of a 3D woodpile structure and atomic layer deposition of 30-nm-thick nickel. Operated near 14 and 24~GHz, the microresonator output revealed numerous coherent magnons with distinct angular dependencies reflecting the underlying face-centred cubic lattice. Micromagnetic simulations show that the edge modes are localised in curved nanocaps and robust against changes in field orientation. Along an edge, they exhibit an unexpected phase evolution. Our findings advance functional microwave circuits with 3D magnonic crystals and fuel their visionary prospects of edge-dominated magnon modes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph)
Advancing atomic electron tomography with neural networks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Accurate determination of three-dimensional (3D) atomic structures is crucial for understanding and controlling the properties of nanomaterials. Atomic electron tomography (AET) offers non-destructive atomic imaging with picometer-level precision, enabling the resolution of defects, interfaces, and strain fields in 3D, as well as the observation of dynamic structural evolution. However, reconstruction artifacts arising from geometric limitations and electron dose constraints can hinder reliable atomic structure determination. Recent progress has integrated deep learning, especially convolutional neural networks, into AET workflows to improve reconstruction fidelity. This review highlights recent advances in neural network-assisted AET, emphasizing its role in overcoming persistent challenges in 3D atomic imaging. By significantly enhancing the accuracy of both surface and bulk structural characterization, these methods are advancing the frontiers of nanoscience and enabling new opportunities in materials research and technology.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
12 pages, 4 figures
Appl. Microsc. 55, 7 (2025)
Extracting the singularity of the logarithmic partition function
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Zhe Wang, Yi-Ming Ding, Zenan Liu, Zheng Yan
In principle, the logarithm of the partition function and its derivatives can be used to rigorously determine the nature of phase transitions. However, in practice, this approach is often ineffective in numerical calculations, since resolving the singularities of the logarithmic partition function requires extremely high precision data especially when distinguishing between weakly first order phase transitions and deconfined quantum critical points. Based on the finite size scaling hypothesis, we propose that the singular contribution to the logarithmic partition function in quantum phase transitions can be extracted by eliminating the leading volume-law term. This is achieved by computing the Renyi thermal entropy (RTE) and its derivative (DRTE). We have derived the scaling relations for RTE and DRTE, which successfully determine the phase transition points and critical exponents through data collapse in various quantum many body systems. Notably, beyond their utility in locating quantum critical points, we find that DRTE is remarkably effective in detecting weakly first order phase transitions, such as in $ JQ $ models, which were initially thought to be continuous deconfined quantum phase transitions. The discontinuity of these transitions is challenging to detect using traditional local physical quantities. This work provides a new and powerful paradigm for studying quantum many body phase transitions.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages,2figures
Pseudo anomalous Hall effect in semiconductors and semimetals: A classical perspective
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
We demonstrate that the non-linear field dependence in the Hall effect, often indistinguishable from the anomalous Hall effect, can be realized entirely within the classical mechanism due to the Lorentz force by analyzing multi-valley models for semiconductors and semimetals. The non-linear component in the Hall resistivity $ \rho_H^{\rm NL}$ originates from carrier mobility anisotropy or the coexistence of different charges. Since $ \rho_H^{\rm NL}$ is inversely proportional to the carrier difference between electrons and holes $ \Delta n$ , it exceeds its zero-field value near charge neutrality. As a practical example, we show that the magnitude of the classical non-linear Hall response in ZrTe$ _5$ is comparable to the experimental values, underscoring the importance of accounting for classical contributions before attributing non-linear Hall effects to quantum mechanisms.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Bi2Te3-Sb2Te3-Bi2Te3 Lateral Heterostructures Grown by Molecular Beam Epitaxy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Puspendu Guha, Sangmin Lee, Eunsu Lee, Hyeonhu Bae, Hoonkyung Lee, Miyoung Kim, Gyu-Chul Yi
Lateral in-plane heterostructures enable precise control of electronic properties and quantum effects in 2D materials. However, their periodic synthesis is challenging because it requires precise control to maintain sharp, coherent interfaces and compatible growth conditions across different domains. Herein, we report the successful heteroepitaxial growth of Bi2Te3-Sb2Te3-Bi2Te3 and periodic lateral heterostructures on hexagonal boron nitride (hBN) through in-situ multiple growth steps at different stages using a molecular beam epitaxy (MBE) system. These trilateral heterostructures are fabricated by growing triangular or hexagonal Bi2Te3 islands at the very beginning, with typical sizes of several hundred nanometers, on the single-crystalline hBN, followed by the lateral growth of Sb2Te3 to form bilateral heterostructures, and finally growing Bi2Te3 on the side facets of the bilateral heterostructures. The electron microscopy results confirm the core area as Bi2Te3, the intermediate layer as Sb2Te3, and the outermost region as Bi2Te3. The resulting heterostructures are approximately 4-8 nm thick and several hundred nanometers in lateral dimensions. These heterostructures are found to grow epitaxially on hBN (< +-4 deg misalignment), and the individual layers are strongly epitaxially aligned with each other. The in-plane heterojunctions are analyzed using the aberration-corrected (Cs-corrected) high-angle annular dark-field scanning transmission electron microscopy technique. We have explored and established the plasmonic properties of these fabricated Bi2Te3-Sb2Te3-Bi2Te3 lateral heterostructures. In addition, the electronic states and the topological properties of the few quintuple layers (QLs) (2- to 4-QLs) Bi2Te3-Sb2Te3 lateral periodic heterostructures are investigated by first-principles calculations.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Electric-field control of zero-dimensional topological states in ultranarrow germanene nanoribbons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Lumen Eek, Esra D. van ‘t Westende, Dennis J. Klaassen, Harold J. W. Zandvliet, Pantelis Bampoulis, Cristiane Morais Smith
Symmetry-protected zero-dimensional (0D) modes, such as corner and end states with fractionalized charge, promise robust qubits and efficient electronics. Yet, reversible, electric-field manipulation and control of these modes has remained elusive. Here, we show theoretically and experimentally electric-field-driven on/off switching of 0D topological end modes in two- and three-hexagon wide germanene nanoribbons in a vertical tunnel junction set-up. We demonstrate the annihilation and restoration of end states in topological samples, but also the induction of 0D topological modes in initially trivial ribbons. The process is reversible, and the system operates at 77 Kelvin. This atomic-scale platform realizes a proof-of-principle for a 0D topological field-effect device, opening an unexpected path for ultra-small memory, quantum computing, and neuromorphic architectures.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Superconducting critical temperature and dimensionality tuning of RbV$_3$Sb$_5$ via biaxial strain
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Tsz Fung Poon, King Yau Yip, Ying Kit Tsui, Lingfei Wang, Kai Ham Yu, Wei Zhang, Zheyu Wang, Taketo Nakatani, Chishiro Michioka, Hiroaki Ueda, Siu Tung Lam, Kwing To Lai, Swee K. Goh
Kagome metal AV$ _3$ Sb$ _5$ (A=K, Rb, Cs) has emerged as an intriguing platform for exploring the interplay between superconductivity and other quantum states. Among the three compounds, RbV$ 3$ Sb$ 5$ has a notably lower superconducting critical temperature ($ T_c$ ) at ambient pressure, posing challenges in exploring the superconducting state. For instance, the upper critical field ($ H{c2}$ ) is small and thus difficult to measure accurately against other control parameters. Hence, enhancing superconductivity would facilitate $ H{c2}$ measurements, providing insights into key superconducting properties such as the dimensionality. In this letter, we report the tuning of the $ T_c$ in RbV$ _3$ Sb$ _5$ through the application of biaxial strain. Utilizing a negative thermal expansion material ZrW$ 2$ O$ 8$ as a substrate, we achieve a substantial biaxial strain of $ \epsilon=1.50%$ , resulting in a remarkable 75% enhancement in $ T_c$ . We investigate the $ H{c2}$ as a function of temperature, revealing a transition from multi-band to single-band superconductivity with increasing tensile strain. Additionally, we study the $ H{c2}$ as a function of field angle, revealing a plausible correlation between the $ T_c$ enhancement and the change in dimensionality of the superconductivity under tensile strain. Further analysis quantitatively illustrates a transition towards two-dimensional superconductivity in RbV$ _3$ Sb$ _5$ when subjected to tensile strain. Our work demonstrates that the application of biaxial strain allows for the tuning of both the $ T_c$ and superconducting dimensionality in RbV$ _3$ Sb$ _5$ .
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
APL Mater. 13, 061121 (2025)
Vibrational properties of epitaxial graphene buffer layer on silicon carbide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Guillaume Radtke (IMPMC), Michele Lazzeri (IMPMC)
The vibrational properties of semiconducting graphene buffer layer epitaxially grown on hexagonal silicon carbide are determined using first-principles calculations on a realistic structural model. Despite the important chemical and structural disorder associated with the partial covalent bonding with the substrate, the buffer-layer carbon atoms still display quasidispersive phonons mimicking those of graphene. The related frequency softening and broadening provide a natural interpretation of the measured Raman signal. The vibrations determining thermal conduction are found to delocalize completely on the SiC substrate, leading to an effective spatial separation between material components determining, respectively, electronic and thermal transport properties. This situation opens perspectives for thermoelectric applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Physical Review B, 2025, 111 (22), pp.L220303
Validity of generalized Gibbs ensemble in a random matrix model with a global $\mathbb{Z}_2$-symmetry
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
$ \mathbb{Z}_2$ symmetry is ubiquitous in quantum mechanical systems where it drives various phase transitions and emergent physics. To understand the role of $ \mathbb{Z}_2$ symmetry in the thermalization of a local observable in a disordered system, we consider random symmetric centrosymmetric (SC) matrices where the exchange symmetry is conserved. Such a conservation law splits the Hilbert space into decoupled subspaces such that the energy spectrum of a SC matrix is a superposition of two pure spectra. After discussing the known results on the correlations of such mixed spectrum, we consider different initial states and analytically compute the entire time evolution of their survival probability and associated timescales. We show that there exist certain initial states which do not decay over a very long timescales such that a measure zero fraction of random SC matrices exhibit spontaneous symmetry breaking. Later, we show that thermalization is violated for a generic local observable in case of the SC matrices, where the generalized Gibbs ensemble accurately captures the equilibrium expectation values.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
8 pages, 4 figures
Crystal structures and electronic and magnetic properties of Janus bilayer Cl3Cr2I3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Suqi Liu, Feng Sun, Aijun Hong
Two-dimensional (2D) magnetic material CrI3 has aroused extensive attention, because it could provide a new platform for investigating the relations between crystal structures and electronic and magnetic properties. Here, we study crystal structures and electronic and magnetic properties of three configurations (Cl-Cl I-I and Cl-I) of Janus bilayer Cl3Cr2I3 with two stacking orders (AB and AA1=3) by using the first principles approach incorporating the spin-orbit coupling (SOC) effect and the dipole correction. It is found that the spin polarization and the SOC effect can expand the lattice constant and the interlayer distance (ID) of the three configurations. Especially, the ID of the I-I configuration is 1 Å larger than that of the Cl-Cl configuration. The total energy calculation results show that the atomic configuration, the SOC effect and the stacking order play an important role in determining the magnetic ground states of the Janus layers. Our results indicate the atomic configurations of the Janus bilayers are not conducive to the increase of critical temperature. Interestingly, the Cl-I configuration has a vertical dipole moment, and its AFM state has large spin splitting. It is revealed that the non-periodic structure, the symmetry breaking of the average potential and the weak interlayer interaction lead to the vertical dipole moment and the abnormal AFM state that is not the most stable state.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quantum disordered ground state and relative proximity to an exactly solvable model in the frustrated magnet CeMgAl${11}$O${19}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
G. Bastien, A. Eliáš, V. Anderle, A. Kancko, C. A. Corrêa, S. Kumar, P. Proschek, J. Prokleška, L. Nádherný, D. Sedmidubský, T. Treu, P. Gegenwart, M. Kratochvílová, M. Žonda, R. H. Colman
The magnetic properties of the triangular magnet CeMgAl$ _{11}$ O$ {19}$ were investigated by magnetization and specific heat measurements down to $ T=0.03,$ K on single crystals grown by the floating zone method. The formation of effective spins $ S\mathrm{eff}= 1/2$ below $ T < 10$ ,K was confirmed both by DFT calculations and specific heat measurements. No magnetic order was found down to $ T=0.03,$ K despite the formation of magnetic correlations observed in specific heat. The measured magnetization was compared with DMRG computation and their agreement supports the proposal of a strongly anisotropic magnetic interaction antiferromagnetically coupling the spin components in the $ ab$ plane and ferromagnetically coupling the spin component along the $ c$ axis. However, our quantitative study of the magnetization indicates a weaker proximity to quantum criticality between ferromagnetism and antiferromagnetism than the previous inelastic neutron scattering study. Finally, we propose that the absence of magnetic order in CeMgAl$ _{11}$ O$ _{19}$ would most probably be related to the structural disorder revealed by single-crystal X-ray diffraction.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures, 8 supplimentary materials pages, 5 supplimentary materials figures
High-speed quantitative nanomechanical mapping by photothermal off-resonance atomic force microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Hans Gunstheimer, Gotthold Fläschner, Jonathan D. Adams, Hendrik Hölscher, Bart W. Hoogenboom
Atomic force microscopy (AFM) is widely used to measure surface topography of solid, soft, and living matter at the nanoscale. Moreover, by mapping forces as a function of distance to the surface, AFM can provide a wealth of information beyond topography, with nanomechanical properties as a prime example. Here we present a method based on photothermal off-resonance tapping (PORT) to increase the speed of such force spectroscopy measurements by at least an order of magnitude, thereby enabling high-throughput, quantitative nanomechanical mapping of a wide range of materials. Specifically, we use photothermal actuation to modulate the position of the AFM probe at frequencies that far exceed those possible with traditional actuation by piezo-driven z scanners. Understanding and accounting for the microscale thermal and mechanical behavior of the AFM probe, we determine the resulting probe position at sufficient accuracy to allow rapid and quantitative nanomechanical examination of polymeric and metallic materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft)
Main manuscript and supplementary information
Microcanonical simulated annealing: Massively parallel Monte Carlo simulations with sporadic random-number generation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
M. Bernaschi, L.A. Fernandez, I. González-Adalid Pemartín, E. Marinari, V. Martin-Mayor, G. Parisi, F. Ricci-Tersenghi, J.J. Ruiz-Lorenzo, D. Yllanes
Numerical simulations of models and theories that describe complex experimental systems $ \unicode{x2014}$ in fields like high-energy and condensed-matter physics$ \unicode{x2014}$ are becoming increasingly important. Examples include lattice gauge theories, which can describe, among others, quantum chromodynamics (the Standard Model description of strong interactions between elementary particles), and spin-glass systems. Beyond fundamental research, these computational methods also find practical applications, among many others, in optimization, finance, and complex biological problems. However, Monte Carlo simulations, an important subcategory of these methods, are plagued by a major drawback: they are extremely greedy for (pseudo) random numbers. The total fraction of computer time dedicated to random-number generation increases as the hardware grows more sophisticated, and can get prohibitive for special-purpose computing platforms. We propose here a general-purpose microcanonical simulated annealing (this http URL) formalism that dramatically reduces such a burden. The algorithm is fully adapted to a massively parallel computation, as we show in the particularly demanding benchmark of the three-dimensional Ising spin glass. We carry out very stringent numerical tests of the new algorithm by comparing our results, obtained on GPUs, with high-precision standard (i.e., random-number-greedy) simulations performed on the Janus II custom-built supercomputer. In those cases where thermal equilibrium is reachable (i.e., in the paramagnetic phase), both simulations reach compatible values. More significantly, barring short-time corrections, a simple time rescaling suffices to map the this http URL off-equilibrium dynamics onto the results obtained with standard simulations.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Hardware Architecture (cs.AR), Computational Physics (physics.comp-ph)
16 pages, 5 figures, 3 tables
Mesoscale FEM Model of Concrete: Statistical Assessment of Inherent Stress Concentrations in Dependence on Phase Heterogeneity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Jan Mašek (1 and 2), Petr Miarka (1 and 2) ((1) Institute of Physics of Materials, Czech Academy of Sciences, Brno, Czech Republic (2) Institute of Structural Mechanics, Faculty of Civil Engineering, Brno University of Technology, Brno, Czech Republic)
Concrete heterogeneity originates from its production process, which involves bonding aggregates with a binder matrix. This study presents a mesoscale finite element model (MFEM) that offers detailed insights into the fracture process at the aggregate-cement matrix interface, focusing on one of concrete’s key properties: its mechanical response. Unlike discrete models, which often average out critical stress concentrations within the mesostructure, the MFEM approach captures detailed stress distributions, revealing localized effects crucial for understanding damage evolution. Although computationally more demanding, the MFEM leverages modern high-performance computing (HPC) to provide a detailed description of the stress field and material damage across different phases and interfaces. Various matrix-to-aggregate stiffness ratios are considered to evaluate the influence of material heterogeneity on the stress field. The results are based on a statistical evaluation of stress concentrations arising from variations in material stiffness. The model is applied to investigate the impact of using recycled crushed bricks as aggregates in concrete, with particular emphasis on the stiffness mismatch between the matrix and aggregates. The study examines how this stiffness contrast affects stress distribution and ultimately influences the composite’s failure mechanisms.
Materials Science (cond-mat.mtrl-sci), Numerical Analysis (math.NA)
Nano-silica based Aqueous Colloidal Gels as Eco-friendly Thixotropic Lubricant
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Arun Kumar, Vivek Kumar, Yogesh M. Joshi, Manjesh K. Singh
The environmental risks posed by traditional oil and grease-based lubricants can be significantly mitigated by adopting water-based alternatives engineered with superior rheological performance. In this work, we present a fundamentally new and environmentally sustainable aqueous thixotropic colloidal gel of silica nanoparticles formed in the presence of NaCl. We conducted a systematic and detailed investigation of their rheological and tribological characteristics. The tribological performance was evaluated against dry and water-lubricated conditions for steel-steel interface. Our experiments demonstrate that the tribological performance of the formulated nanoparticle gel can be optimized by tuning its rheological properties. A combination of super-low friction and negligible wear was observed. The friction coefficient reduced by up to 97.46% (from 0.63 to 0.016) compared to dry sliding, and by 97.04% (from 0.541 to 0.016) compared to water lubrication. Similarly, the specific wear rate decreased by up to 99.62% and 96.10% under dry conditions and water lubrication respectively. This performance is attributed to a thixotropic, chemically robust gel formed via van der Waals interactions between silica flocs, enabling self-repairing properties, continuous tribo-film formation, and a nano-bearing effect from silica nanoparticles. These attributes enable the gel to maintain and regain its structure during periods of non-shear while also forming a thin film with sufficiently low viscosity to slip into the interfacial contact zone and continuously replenish it with lubricant.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
10 figures, supporting information
Correcting systematic errors in the likelihood optimization of underdamped Langevin models of molecular dynamics trajectories
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
David Daniel Girardier, Hadrien Vroylandt, Sara Bonella, Fabio Pietrucci
Since Kramers’ pioneering work in 1940, significant efforts have been devoted to studying Langevin equations applied to physical and chemical reactions projected onto few collective variables, with particular focus on the inference of their parameters. While the inference for overdamped Langevin equations is well-established and widely applied, a notable gap remains in the literature for underdamped Langevin equations, which incorporate inertial effects and velocities. This gap arises from the challenge of accessing velocities solely through finite differences of positions, resulting in spurious correlations. In this letter, we propose an analytical correction for these correlations, specifically designed for a likelihood-maximization algorithm that exploits short, non-ergodic trajectories that can be obtained at reasonable numerical cost. The accuracy and robustness of our approach are tested across a benchmark case and a realistic system. This work paves the way for applying generalized Langevin equation inference to chemical reactions.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
Full-Gap Superconductivity in BaAs/Ferropnictide Heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Ming-Qiang Ren, Qiang-Jun Cheng, Hui-Hui He, Ze-Xian Deng, Fang-Jun Cheng, Yong-Wei Wang, Cong-Cong Lou, Qinghua Zhang, Lin Gu, Kai Liu, Xu-Cun Ma, Qi-Kun Xue, Can-Li Song
Interfacial interactions often promote the emergence of unusual phenomena in two-dimensional systems, including high-temperature superconductivity. Here, we report the observation of full-gap superconductivity with a maximal spectroscopic temperature up to 26 K in a BaAs monolayer grown on ferropnictide Ba(Fe$ _{1-x}$ Co$ _x$ )$ _2$ As$ 2$ (abbreviated as BFCA) epitaxial films. The superconducting gap remains robust even when the thickness of underlying BFCA is reduced to the monolayer limit, in contrast to the rapid suppression of $ T\textrm{c}$ in standalone BFCA thin films. We reveal that the exceptional crystallinity of the BaAs/BFCA heterostructures, featured by their remarkable electronic and geometric uniformities, is crucial for the emergent full-gap superconductivity with mean-field temperature dependence and pronounced bound states within magnetic vortices. Our findings open up new avenues to unravel the mysteries of unconventional superconductivity in ferropnictides and advance the development of FeAs-based heterostructures.
Superconductivity (cond-mat.supr-con)
6 pages, 4 figures
Phys. Rev. Lett. 134, 246203 (2025)
Atomic-scale imaging of electronic nematicity in ferropnictides
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Qiang-Jun Cheng, Yong-Wei Wang, Ming-Qiang Ren, Ze-Xian Deng, Cong-Cong Lou, Xu-Cun Ma, Qi-Kun Xue, Can-Li Song
Electronic nematicity, a correlated state characterized by broken rotational symmetry, has been recognized as a ubiquitous feature intertwined with unconventional electron pairing in various iron-based superconductors. Here we employ spectroscopic-imaging scanning tunneling microscopy to visualize atomic-scale electronic nematicity directly on FeAs planes of a prototypical ferropnictide BaFe$ 2$ As$ 2$ . Spatially, the nematic order appears as 4$ a{\textrm{Fe}}$ -spaced stripes ($ a{\textrm{Fe}} \sim $ 0.28 nm is the in-plane Fe-Fe distance) within homogeneously and orthogonally oriented nano-domains. The energy-resolved conductance maps reveal a pronounced energy-dependence of the nematic order parameter that experiences a sign change at approximately 30 meV. This characteristic behavior coincides with energy-dependent orbital splitting previously identified in momentum space, but is remarkably visualized in real space for the first time in our study. Moreover, the electronic nematicity exhibits pronounced sensitivity to single impurities and is notably suppressed by cobalt substitution for Fe atoms, promoting optimal superconductivity when nematic fluctuations are strongest. Our results provide pivotal experimental insights for developing a microscopic model of nematic order, thus paving the way to study its complex relationship with unconventional superconductivity.
Superconductivity (cond-mat.supr-con)
25 pages, 12 figures
Universally enhanced superconductivity and coexisting ferroelectricity at oxide interfaces
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Meng Zhang, Ming Qin, Yanqiu Sun, Siyuan Hong, Yanwu Xie
The coexistence of superconductivity and ferroelectricity is rare due to their conflicting requirements: superconductivity relies on free charge carriers, whereas ferroelectricity typically occurs in insulating systems. At LaAlO3/KTaO3 interfaces, we demonstrate the coexistence of two-dimensional superconductivity and ferroelectricity, enabled by the unique properties of KTaO3 as a quantum paraelectric. Systematic gating and poling experiments reveal a universal enhancement of the superconducting transition temperature (Tc) by 0.2-0.6 K and bistable transport properties, including hysteresis, strongly suggesting the existence of switchable ferroelectric polarization in the interfacial conducting layer. Hysteresis loops indicate robust ferroelectricity below 50 K. The Tc enhancement is attributed to ferroelectric polarization-induced reduction in dielectric constant, which narrows the interfacial potential well, confining carriers closer to the interface. The bistability arises from switchable ferroelectric polarization, which modulates the potential well depending on polarization direction. These findings establish a straightforward mechanism coupling ferroelectricity and superconductivity, providing a promising platform for exploring their interplay.
Superconductivity (cond-mat.supr-con)
Endoreversible Stirling cycles: plasma engines at maximal power
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Gregory Behrendt, Sebastian Deffner
Endoreversible engine cycles are a cornerstone of finite-time thermodynamics. We show that endoreversible Stirling engines operating with a one-component plasma as working medium run at maximal power output with the Curzon-Ahlborn efficiency. As a main result, we elucidate that this is actually a consequence of the fact that the caloric equation of state depends only linearly on temperature and only additively on volume. In particular, neither the exact form of the mechanical equation of state, nor the full fundamental relation are required. Thus, our findings immediately generalize to a larger class of working plasmas, far beyond simple ideal gases. In addition, we show that for plasmas described by the photonic equation of state the efficiency is significantly lower. This is in stark contrast to endoreversible Otto cycles, for which photonic engines have an efficiency larger than the Curzon-Ahlborn efficiency.
Statistical Mechanics (cond-mat.stat-mech), Plasma Physics (physics.plasm-ph)
7 pages, 4 figures
Quantum dynamical signatures of non-Hermitian boundary modes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Fan Yang, Maria Zelenayova, Paolo Molignini, Emil J. Bergholtz
The non-Hermitian bulk-boundary correspondence features an interplay between the non-Hermitian skin effect and anomalous boundary-mode behavior. Whereas the skin effect is known to manifest itself in quantum dynamics in the form of chiral damping, it has remained less clear what impact the boundary modes may have. Here we derive experimentally accessible signatures of the boundary modes. We also establish clear criteria, based on the effective generalized Brillouin zone, that determine when bulk and boundary effects can be dynamically discerned using the Liouvillian separation gap. This leads to telltale signatures in both stable regimes – where particle number remains finite – and in the unstable regimes – where a macroscopic boundary mode population occurs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Optics (physics.optics), Quantum Physics (quant-ph)
21 pages, 7 figures
Direct imaging of quantum interference and Non-Abelian entanglement in Hopfion: an magnetic soliton possess loop-like anyonic properties
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Jiawei Dong, Xin Zhang, Hailong Shen, Haoyu Wu, Zhenyu Ma, Yong Deng, Wenyu Hu, Wenbin Qiu, Bo Liu, Xiaoyi Wang, Yihan Wang, Longqing Chen, Yang Qiu, Jian Ma, Xudong Cui, Kun Zhang, Pierre Ruterana
This work provides the first experimental elucidation of quantum topological effects in individual hopfions, establishing their potential as building blocks for three-dimensional topological quantum spintronics. The observed Non-Abelian characteristics suggest pathways toward fault-tolerant quantum operations through controlled hopfion braiding in engineered magnetic metamaterials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other)
Statistical theory of charged particle systems including triple bound states – and the Collaboration Lviv-Rostock
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Honoring the hundredth anniversary of the birthday of Ihor R. Yuknovskii we analyze new developments in the statistical thermodynamics of Coulomb systems. The basic idea of this work is to demonstrate that the exponential potential used in the first papers of Yukhnovskii is an appropriate reference system for a description of classical and quantum charged particle systems. We briefly discuss the collaboration between the groups of Ihor R. Yuknovskii in Lviv and Günter Kelbg in Rostock and analyze several approaches based on pair correlation functions and cluster expansion in the classical as well as in the quantum case. Finally, we discuss the progress in the statistical description of bound states of three particles as in helium plasmas and in MgCl$ _2$ -solutions in the classical case and present new results regarding the influence of three-particle bound states. In particular, we give new expressions for the cluster integrals and the mass action functions of helium atoms and ionic triple associates as well as for the equation of state (EoS).
Soft Condensed Matter (cond-mat.soft)
28 pages, 9 figures
Preferred Synthesis of Armchair SnS2 Nanotubes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Abid, Luneng Zhao, Ju Huang, Yongjia Zheng, Yuta Sato, Qingyun Lin, Zhen Han, Chunxia Yang, Tianyu Wang, Bill Herve Nduwarugira, Yicheng Ma, Lingfeng Wang, Yige Zheng, Hang Wang, Salman Ullah, Afzal Khan, Qi Zhang, Wenbin Li, Junfeng Gao, Bingfeng Ju, Feng Ding, Yan Li, Kazu Suenaga, Shigeo Maruyama, Huayong Yang, Rong Xiang
In this work, we present the synthesis of tin disulfide (SnS2) nanotubes (NTs) with preferred chiral angle. A sacrificial template is used to create channels of boron nitride nanotubes (BNNTs) with an optimized diameter of 4-5 nm, inside of which SnS2 NTs are formed with the high yield and structural purity. Atomic resolution imaging and nano-area electron diffraction reveal that these synthesized SnS2 NTs prefer to have an armchair configuration with a probability of approximately 85%. Calculations using density functional theory (DFT) reveal a negligible difference in the formation energy between armchair and zigzag NTs, suggesting that structural stability does not play a key role in this chirality-selective growth. However, a detailed TEM investigation revealed that some SnS2 nanoribbons are found connected to the ends of SnS2 NTs, and that these nanoribbons primarily have a zigzag configuration. Subsequent DFT and machine learning potential molecular dynamic simulations verify that nanoribbons with zigzag configurations are more stable than armchair ones, and indeed zigzag nanoribbons aligned along the BNNT axis tend to roll up to form an armchair SnS2 NTs. Finally, this “zigzag nanoribbon to armchair nanotube” transition hypothesis is verified by in-situ high-resolution transmission electron microscopy, in which the transformation of SnS2 nanoribbons into a nanotube is reproduced in real time. This work is the first demonstration of preferred-chirality growth of transition metal dichalcogenide nanotubes.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Electron-optical phonon scattering in quantum wells in a tilted quantizing magnetic field
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
M.P. Telenkov, Yu.A. Mityagin, D.S.Korchagin
The electron scattering with longitudinal polar optical phonons in a quantizing magnetic field tilted to the plane of quantum well layers is studied. The scattering rate’s behavior at variation of the magnetic field magnitude and orientation is established.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
arXiv admin note: text overlap with arXiv:2505.08028
The many faces of rotating quantum turbulence
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Julian Amette Estrada, Marc E. Brachet, Pablo D. Mininni
Quantum turbulence shares many similarities with classical turbulence in the isotropic and homogeneous case, despite the inviscid and quantized nature of its vortices. However, when quantum fluids are subjected to rotation, their turbulent dynamics depart significantly from the classical expectations. We explore the phenomenology of rotating quantum turbulence, emphasizing how rotation introduces new regimes with no classical analogs. We review recent theoretical, experimental, and numerical developments, and present new numerical results that map out distinct dynamical regimes arising from the interplay of rotation, quantization, non-linearities, and condensed matter regimes. In particular, we show the importance of distinguishing the dynamics of rotating quantum fluids in the slowly rotating, rapidly rotating, and low Landau level regimes. The findings have implications for the dynamics of liquid helium, atomic Bose-Einstein condensates, and neutron stars, and show how rotating quantum fluids can serve as a unique platform bridging turbulence theory and condensed matter physics revealing novel states of out-of-equilibrium quantum matter.
Quantum Gases (cond-mat.quant-gas)
Orbital Order and Superconductivity in Bilayer Nickelate Compounds
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Giniyat Khaliullin, Jiří Chaloupka
We propose a theory for bilayer nickelate materials, where a large tetragonal field - intrinsic or induced by epitaxial strain - lifts the orbital degeneracy and localizes the $ 3z^2-r^2$ orbital states. These states host local spins $ S=1/2$ bound into singlets by strong interlayer coupling, and their dynamics is described by weakly dispersive singlet-triplet excitations (“triplons”). The charge carriers occupy the wide bands of $ x^2-y^2$ symmetry, and their Cooper pairing is mediated by the high-energy triplon excitations. As the $ x^2-y^2$ band filling increases, i.e. moving further away from the Ni$ ^{3+}$ valence state, the indirect Ruderman-Kittel-Kasuya-Yosida interactions between local spins induce spin-density-wave order via triplon condensation. Implications of the model for compressively strained La$ _3$ Ni$ _2$ O$ _7$ films and electron doped oxychloride Sr$ _3$ Ni$ _2$ O$ _5$ Cl$ _2$ are discussed.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures
Superconductivity in the spin-state crossover materials: Nickelates with planar-coordinated low-spin Ni$^{2+}$ ions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Jiří Chaloupka, Giniyat Khaliullin
We theoretically study quasi-two-dimensional nickel compounds, where the nickel ions assume Ni$ ^{2+}$ $ d^8$ valence state and feature a low-spin $ S=0$ ground state quasidegenerate with $ S=1$ ionic excitations. Such a level structure is supported by square-planar coordination of nickel ions or a suitable substitution of apical oxygens. We construct the corresponding singlet-triplet exchange model and explore its phase diagram and excitation spectrum. By hole doping, we further introduce mobile Ni$ ^{3+}$ $ d^7$ ionic configurations with effective spins $ S=1/2$ , and analyze their interactions with the $ d^8$ singlet-triplet background. The interplay with the triplet excitations in the $ d^8$ sector is found to have a deep impact on the propagation of the doped hole-like charge carriers and is identified as a powerful source of Cooper pairing among them.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 6 figures
Real-space visualization of orbital-selective superconductivity in FeSe
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Sang Yong Song, Gábor B. Halász, Jiaqiang Yan, Benjamin J. Lawrie, Petro Maksymovych
We investigate the orbitally resolved superconducting properties of bulk FeSe using scanning tunneling microscopy (STM). We find that the spectral weights of both the large $ \Delta_1$ and small $ \Delta_2$ superconducting gaps remain nearly unchanged at the top Se sites as the STM tip approaches atomic contact. In contrast, the spectral weight of $ \Delta_2$ increases significantly at the Fe and bottom Se sites. These results suggest that the gap $ \Delta_2$ is localized in the xy-plane and likely associated with the dxy orbital band. Furthermore, we observe a long-range suppression of the large gap $ \Delta_1$ near one-dimensional (1D) defects such as twin boundaries, wrinkles, and step edges, whereas $ \Delta_2$ remains robust. This indicates that the two superconducting gaps respond differently to such 1D defects. High-resolution measurement using a Pb-coated tip reveals localized in-gap states near 1D defects, indicating possible defect-induced magnetism. Our findings highlight the contrasting behaviors of gap $ \Delta_1$ and gap $ \Delta_2$ in response to local electronic and magnetic environments and provide real-space evidence for orbital-selective superconductivity.
Superconductivity (cond-mat.supr-con)
From toroids to helical tubules: Kirigami-inspired programmable assembly of two-periodic curved crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Mason Price, Daichi Hayakawa, Thomas E. Videbæk, Rupam Saha, Botond Tyukodi, Michael F. Hagan, Seth Fraden, Gregory M. Grason, W. Benjamin Rogers
Biology is full of intricate molecular structures whose geometries are inextricably linked to their function. Many of these structures exhibit varying curvature, such as the helical structure of the bacterial flagellum, which is critical for their motility. Because synthetic analogues of these shapes could be valuable platforms for nanotechnologies, including drug delivery and plasmonics, controllable synthesis of variable-curvature structures of various material systems, from fullerenes to supramolecular assemblies, has been a long-standing goal. Like two-dimensional crystals, these structures have a two-periodic symmetry, but unlike standard two-dimensional crystals, they are embedded in three dimensions with complex, spatially-varying curvatures that cause the structures to close upon themselves in one or more dimensions. Here, we develop and implement a design strategy to program the self-assembly of a complex spectrum of two-periodic curved crystals with variable periodicity, spatial dimension, and topology, spanning from toroids to achiral serpentine tubules to both left- and right-handed helical tubules. Our design strategy uses a kirigami-based mapping of 2D planar tilings to 3D curved crystals that preserves the periodicity, two-fold rotational symmetries, and subunit dimensions via the arrangement of disclination defects. We survey the modular geometry of these curved crystals and infer the addressable subunit interactions required to assemble them from triangular subunits. To demonstrate this design strategy, we program the self-assembly of toroids, helical- and serpentine-tubules from DNA origami subunits. A simulation model of the assembly pathways reveals physical considerations for programming the geometric specificity of angular folds in the curved crystal required to avoid defect-mediated misassembly.
Soft Condensed Matter (cond-mat.soft)
12 Pages, 5 Figures, Supplement 32 Pages, 26 Figures, 9 Tables
Pseudocriticality in antiferromagnetic spin chains
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Sankalp Kumar, Sumiran Pujari, Jonathan D’Emidio
Weak first-order pseudocriticality with approximate scale invariance has been observed in a variety of settings, including the intriguing case of deconfined criticality in 2+1 dimensions. Recently, this has been interpreted as extremely slow flows (“walking behavior”) for real-valued couplings in proximity to a bona fide critical point with complex-valued couplings, described by a complex conformal field theory (CFT). Here we study an SU($ N$ ) generalization of the the Heisenberg antiferromagnet, which is a familiar model for deconfined criticality in 2+1 dimensions. We show that in 1+1 dimensions the model is located near a complex CFT, whose proximity can be tuned as a function of $ N$ . We employ state-of-the-art quantum Monte Carlo simulations for continuous $ N$ along with an improved loop estimator for the Rényi entanglement entropy based on a nonequilibrium work protocol. These techniques allow us to track the central charge of this model in detail as a function of $ N$ , where we observe excellent agreement with CFT predictions. Notably, this includes the region $ N>2$ , where the CFT moves into the complex plane and pseudocritical drifts enable us to recover the real part of the complex central charge with remarkable accuracy. Since the present model with $ N=3$ is also equivalent to the spin-1 biquadratic model, our work sheds new light on the dimerized phase of the spin-1 chain, demonstrating that it is pseudocritical and proximate to a complex CFT.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Lattice (hep-lat), High Energy Physics - Theory (hep-th)
4+11 pages, 3+7 figures
Unraveling the nature of excitons in the 2D magnetic semiconductor CrSBr
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Maciej Smiertka, Michal Rygala, Katarzyna Posmyk, Paulina Peksa, Mateusz Dyksik, Dimitar Pashov, Kseniia Mosina, Zdenek Sofer, Mark van Schilfgaarde, Florian Dirnberger, Michal Baranowski, Swagata Acharya, Paulina Plochocka
Excitonic effects dominate the optoelectronic properties of van der Waals semiconductors, a characteristic equally true for recently discovered 2D magnetic semiconductors. This brings new possibilities for investigating fundamental interactions between excitons and a correlated spin environment, particularly pronounced in CrSBr. Here, we demonstrate that CrSBr hosts both localised Frenkel-like and delocalised Wannier-Mott-like excitons a duality rare among other magnetic or nonmagnetic 2D materials. Our combined theoretical and experimental high magnetic field studies reveal that these two exciton types exhibit strikingly different responses to magnetic and lattice perturbations. We show that the high-energy exciton (XB) is an order of magnitude more sensitive to magnetic order changes than XA, establishing XB as a highly effective optical probe of the magnetic state. The presented self-consistent many-body perturbation theory provides detailed insight into their electronic and spatial structure, quantitatively explaining the observed differences, based on their relative Wannier-Mott and Frenkel characters. By probing the diamagnetic response in magnetic fields up to 85 T, we estimate the relative spatial extent of the two excitons, with results aligning well with the predictions of our many-body perturbation theory. Furthermore, we observe exceptionally distinct coupling of the two excitons to lattice vibrations: a strong temperature dependent redshift for XB between antiferromagnetic and ferromagnetic phases, which is almost temperature-invariant for XA. This is attributed to XBs tendency for out-of-plane delocalisation in the FM phase, leading to enhanced coupling with Ag phonon modes. These findings provide a detailed microscopic understanding of both types of excitons and their distinct magneto-exciton coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Excluded volume effect of surfactant ligands on the shape of nascent nanocrystal
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
A. Baumketner, D. Anokhin, Ya. Patsahan
We investigate the effect of the excluded volume of surfactant ligands on the shape of incipient quantum dots (QDs) to which they are attached. We consider a model in which ligands are represented by hard-sphere particles that are bound to the surface of a nanoparticle (NC) that is cast in the shape of a prism. It is found in Monte Carlo simulations that the ensemble of relevant NC conformations consists of a small number of specific states that take on the form of nanoplates and nanorods. The shape of these states can be well described by the derived theoretical models. At increasing ligand density, the free energy of different states is seen to be approximately the same, suggesting that excluded volume interactions among ligands acts to narrow down the conformational space accessible to an NC without creating a statistical preference for any particular configuration.
Soft Condensed Matter (cond-mat.soft)
13 pages, 5 figures
Method of canonical transformations in the theory of quantum gases interacting with radiation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
M. S. Bulakhov, A. S. Peletminskii, P. P. Kostrobij, I. A. Ryzha, Yu. V. Slyusarenko
An approach to the theoretical study of effects and phenomena in quantum gases interacting with radiation is proposed. The approach is based on a modification of the canonical transformation method, which was once used to diagonalize Hamiltonians describing the interaction of electrons with phonons in a solid. The capabilities of the method are demonstrated by studying the influence of photons on the spectral characteristics of atoms of quantum gases interacting with radiation. Within the framework of the developed approach, the effect of “dressing” atoms of quantum gases by a cloud of virtual photons is investigated and expressions for the energy characteristics of such dressed atoms - quasiparticles are obtained. The problem of defining the concept of the effective mass of such quasiparticles is discussed.
Statistical Mechanics (cond-mat.stat-mech)
13 pages
A General Framework for Linking Free and Forced Fluctuations via Koopmanism
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Valerio Lucarini, Manuel Santos Gutierrez, John Moroney, Niccolò Zagli
The link between forced and free fluctuations for nonequilibrium systems can be described via a generalized version of the celebrated fluctuation-dissipation theorem. The use of the formalism of the Koopman operator makes it possible to deliver an intepretable form of the response operators written as a sum of exponentially decaying terms, each associated one-to-one with a mode of natural variability of the system. Here we showcase on a stochastically forced version of the celebrated Lorenz ‘63 model the feasibility and skill of such an approach by considering different Koopman dictionaries, which allows us to treat also seamlessly coarse-graining approaches like the Ulam method. Our findings provide support for the development of response theory-based investigation methods also in an equation-agnostic, data-driven environment.
Statistical Mechanics (cond-mat.stat-mech), Chaotic Dynamics (nlin.CD), Data Analysis, Statistics and Probability (physics.data-an)
18 pages, 3 figures
Antiferromagnetism and Tightly Bound Cooper Pairs Induced by Kinetic Frustration
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Yixin Zhang, Cristian Batista, Yang Zhang
Antiferromagnetism and superconductivity are often viewed as competing orders in correlated electron systems. Here, we demonstrate that kinetic frustration in hole motion facilitates their coexistence within the square-lattice repulsive Hubbard model. Combining exact analytical solutions on tailored geometries with large-scale numerical simulations, we reveal a robust pairing mechanism: holes on opposite sublattices behave as if they carry opposite effective charges due to spin singlet formation from kinetic frustration. This emergent property suppresses phase separation and fosters a coherent $ d$ -wave superconducting channel embedded within a long-range antiferromagnetic background. Our findings establish a minimal yet broadly applicable framework for stabilizing strong-coupling superconductivity in doped Mott insulators.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
8+11 pages, 7+15 figures
Compressibility measurement of the thermal MI–BG transition in an optical lattice
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Phil Russ, Mi Yan, Nicholas Kowalski, Laura Wadleigh, Vito W. Scarola, Brian DeMarco
Disorder can be applied to transform conducting to insulating states by localizing individual quantum particles. The interplay between disorder and interactions in many-particle systems leads to a richer tapestry of quantum phase transitions. Here, we report the measurement in an ultracold lattice gas of a disorder-induced transition from a state with small disorder-independent compressibility to a state for which compressibility increases with disorder. At zero temperature this is the transition from a Mott insulator (MI) to a Bose glass (BG), both of which are insulating states. This transformation is observed using measurements of core compressibility. By determining how double occupancy changes with atom number, we identify the threshold disorder strength required to switch from disorder-independent MI-like to disorder-dependent BG-like compressible behavior.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
6 pages, 4 figures
Jamming as a topological satisfiability transition with contact number hyperuniformity and criticality
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Jin Shang, Yinqiao Wang, Deng Pan, Yuliang Jin, Jie Zhang
The jamming transition between flow and amorphous-solid states exhibits paradoxical properties characterized by hyperuniformity (suppressed spatial fluctuations) and criticality (hyperfluctuations), whose origin remains unclear. Here we model the jamming transition by a topological satisfiability transition in a minimum network model with simultaneously hyperuniform distributions of contacts, diverging length scales and scale-free clusters. We show that these phenomena stem from isostaticity and mechanical stability: the former imposes a global equality, and the latter local inequalities on arbitrary sub-systems. This dual constraint bounds contact number fluctuations from both above and below, limiting them to scale with the surface area. The hyperuniform and critical exponents of the network model align with those of frictionless jamming, suggesting a new universality class of non-equilibrium phase transitions. Our results provide a minimal, dynamics-independent framework for jamming criticality and hyperuniformity in disordered systems.
Soft Condensed Matter (cond-mat.soft)
13 pages, 9 figures, 1 table
Nucleation and propagation of fracture in viscoelastic elastomers: A complete phase-field theory
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Farhad Kamarei, Evan Breedlove, Oscar Lopez-Pamies
This paper presents a macroscopic theory, alongside its numerical implementation, aimed at describing, explaining, and predicting the nucleation and propagation of fracture in viscoelastic materials subjected to quasistatic loading conditions. The focus is on polymers, in particular, on elastomers. To this end, the starting point of this work is devoted to summarizing the large body of experimental results on how elastomers deform, nucleate cracks, and propagate cracks when subjected to mechanical loads. When viewed collectively, the experiments make it plain that there are three basic ingredients that any attempt at a complete macroscopic theory of fracture in elastomers ought to account for: i) the viscoelasticity of the elastomer; ii) its strength; and iii) its fracture energy. A theory is then introduced that accounts for all these three basic ingredients by extending the phase-field theory initiated by Kumar, Francfort, and Lopez-Pamies (J. Mech. Phys. Solids 112 (2018), 523–551) for elastic brittle materials to seamlessly incorporate viscous energy dissipation by deformation, a generalized strength surface that is a hypersurface in stress-deformation space (and not just in stress space as for elastic brittle materials), and the pertinent Griffith criticality condition for materials that dissipate energy not just by the creation of surface but also by deformation, in this case, by viscous deformation (Shrimali and Lopez-Pamies (2023) Extreme Mech. Lett. 58, 101944). From an applications point of view, the proposed theory amounts to solving an initial-boundary-value problem comprised of two nonlinear PDEs coupled with a nonlinear ODE for the deformation field, a tensorial internal variable, and the phase field. A robust scheme is presented to generate solutions for these equations.
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph)
Transfer-matrix approach to the Blume-Capel model on the triangular lattice
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Dimitrios Mataragkas, Alexandros Vasilopoulos, Nikolaos G. Fytas, Dong-Hee Kim
We investigate the spin-$ 1$ Blume-Capel model on an infinite strip of the triangular lattice using the transfer-matrix method combined with a sparse-matrix factorization technique. Through finite-size scaling analysis of numerically exact spectra for strip widths up to $ L = 19$ , we accurately locate the tricritical point improving upon recent Monte Carlo estimates. In the first-order regime, we observe exponential scaling of the spectral gap, reflecting the linear growth of interfacial tension as the temperature decreases below the tricritical point. Finally, we validate our tricritical point estimate through precise agreement with conformal field theory predictions for the tricritical Ising universality class. Our results underscore the continued utility of the transfer-matrix approach for studying phase transitions in complex lattice models.
Statistical Mechanics (cond-mat.stat-mech)
9 pages, 7 figures, APS style
Lattice-dependent orientational order in active crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Via mechanisms not accessible at equilibrium, self-propelled particles can form phases with positional order, such as crystals, and with orientational order, such as polar flocks. However, the interplay between these two types of order remains relatively unexplored. Here, we address this point by studying crystals of active particles that turn either towards or away from each other, which can be experimentally realised with phoretic or Janus colloids or with elastically-coupled walker robots. We show that, depending on how these interactions vary with interparticle distance, the particles align along directions determined by the underlying crystalline lattice. To explain the results, we map the orientational dynamics of the active crystal onto a lattice of spins that interact via (anti-)ferromagnetic alignment with each other plus nematic alignment with the lattice directions. Our findings indicate that orientational and positional order can be strongly coupled in active crystals, thus suggesting strategies to control orientational order by engineering the underlying crystalline lattice.
Soft Condensed Matter (cond-mat.soft)
Mixed phases in a Fermi–Hubbard model describing altermagnetism
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
We study an extension of the 2D Fermi–Hubbard model, which was recently introduced in [Das et al., Phys. Rev. Lett. 132, 263402 (2024)] and shown to describe altermagnetism that can be studied in cold atom systems. Using an updated Hartree–Fock method that can detect instabilities towards phase separation, we show that the model is in a mixed phase in large parts of the parameter regime at half-filling. We argue that the occurrence of a mixed phase is an indication of exotic physics which, in this model, occurs in parameter regimes accessible in cold atom experiments.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), Mathematical Physics (math-ph)
5 pages
Superconductivity in a Chern band: effect of time-reversal-symmetry breaking on superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Bernhard E. Lüscher, Mark H. Fischer
Time-reversal-symmetry breaking is generally understood to be detrimental for superconductivity. However, recent experiments found superconductivity emerging out of a normal state showing a finite anomalous Hall effect, indicative of time-reversal-symmetry breaking, in diverse systems from kagome metals, $ 1T’$ -WS$ _2$ , to twisted MoTe$ 2$ and rhombohedral graphene. Motivated by these findings, we study the stability of superconducting orders and the mechanisms that suppress superconductivity in the prototypical anomalous Hall system, the Haldane model, where complex hopping parameters result in loop-current order with a compensated flux pattern. We find that neither spin-singlet nor spin-triplet states are generically suppressed, but the real-space sublattice structure plays a crucial role in the stability of the orders. Interestingly, the nearest-neighbor chiral states of $ d\pm id$ or $ p\pm i p$ symmetry couple linearly to the flux, such that the two otherwise degenerate chiralities split under finite flux. As an experimental probe to distinguish the various orders in this system, we study the anomalous thermal Hall effect, $ \kappa{xy} / T$ , which vanishes at zero temperature for topologically trivial superconducting states, but reaches a finite value corresponding to the Chern number in a topologically non-trivial superconducting state. Our results illustrate that broken time-reversal symmetry through a finite flux is neither generically destructive for superconductivity, nor does it imply non-trivial topological order of the emerging superconducting state. However, in the case of multiple competing pairing channels, the loop-current order can favor a chiral superconducting state.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 7 figures
Formation of ultracold $^{39}$K$^{133}$Cs Feshbach molecules
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Charly Beulenkamp, Krzysztof P. Zamarski, Robert C. Bird, C. Ruth Le Sueur, Jeremy M. Hutson, Manuele Landini, Hanns-Christoph Nägerl
We report the creation of an ultracold gas of bosonic $ ^{39}$ K$ ^{133}$ Cs molecules. We first demonstrate a cooling strategy relying on sympathetic cooling of $ ^{133}$ Cs to produce an ultracold mixture. From this mixture, weakly bound molecules are formed using a Feshbach resonance at 361.7 G. The molecular gas contains $ 7.6(10)\times 10^3$ molecules with a lifetime of about 130 ms, limited by two-body decay. We perform Feshbach spectroscopy to observe several new interspecies resonances and characterize the bound state used for magnetoassociation. Finally, we fit the combined results to obtain improved K-Cs interaction potentials. This provides a good starting point for the creation of ultracold samples of ground-state $ ^{39}$ K$ ^{133}$ Cs molecules.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
Ultrastable jammed sphere packings with a wide range of particle dispersities
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
We show that for a standard continuously-polydisperse model with particle-diameter distribution $ P(\sigma) \propto \sigma^{-3}$ and polydispersity index $ \Delta$ , employing a combination of standard SWAP moves and transient degree of freedom (TDOF) moves during a Lubachevsky-Stillinger-like particle-growth process dramatically increases the generated packings’ jamming densities $ \phi_{\rm J}(\Delta)$ and coordination numbers $ Z_{\rm J}(\Delta)$ , for a wide range of $ \Delta$ . We find that the fractional increase in $ \phi_{\rm J}(\Delta)$ obtained by employing these moves first increases rapidly with $ \Delta$ , then plateaus at $ 6-7%$ over the range $ 0.10 \lesssim \Delta \leq 50$ ; the obtained $ \phi_{\rm J}$ are as high as $ 0.747$ (for $ \Delta = 0.50$ ). These density increases are achieved without producing crystallization or fractionation. SWAP and TDOF moves also reduce packings’ rattler populations by as much as 96% and increase their bulk moduli by as much as 154%.
Soft Condensed Matter (cond-mat.soft)
Thin active nematohydrodynamic layers: asymptotic theories and instabilities
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Mehrana R. Nejad, L. Mahadevan
Starting from a three-dimensional description of an active nematic layer, we employ an asymptotic theory to derive a series of low-dimensional continuum models that capture the coupled dynamics of flat and curved films, including variations in film thickness, shape deformations, internal velocity fields, and the dynamics of orientational order.
Using this asymptotic theory, we investigate instabilities driven by activity in both the nematic and isotropic phases for cylindrical and flat films. In the flat case, we demonstrate that incorporating shape and thickness variations fundamentally alters the bend and splay nature of instabilities compared to conventional two dimensional nematic instabilities. In the isotropic phase, we find that both extensile and contractile activity can induce nematic order, in contrast with active nematics on fixed surfaces, where only extensile activity leads to ordering. For the case of curved geometries such as a cylindrical film, we reveal that thickness and shape instabilities are inherently coupled. In the isotropic phase, the emergence of nematic order triggers both thickness and shape instabilities. In the nematic phase, contractile activity induces thickness instabilities, which in turn drive geometric deformations. Our results highlight the crucial interplay between activity, thickness variations, and curvature, providing new insights into the behavior of active nematic films beyond the conventional two dimensional paradigm that has been studied to date.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Update of Hartree–Fock theory for Hubbard-like models
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
We show that the standard textbook description of (restricted) Hartree–Fock theory for (Fermi) Hubbard-like models is in need of an update, and we present such an update allowing us to correct basic and established results in the condensed matter physics literature that are qualitatively wrong. Our update amounts to adding a test which reliably checks the thermodynamic stability of solutions of Hartree–Fock equations. This stability test makes it possible to detect, by simple means and with certainty, regions in phase space where the model exhibits mixed phases where two conventional phases coexist and translation invariance is broken in complicated ways; in such a mixed phase, unconventional physics is to be expected. Our results show that mixed phases are ubiquitous in Hubbard-like models in arbitrary dimensions.
Strongly Correlated Electrons (cond-mat.str-el), Mathematical Physics (math-ph)
31 pages
Mott metal-insulator transition in a modified periodic Anderson model: Insights from entanglement entropy and role of short-range spatial correlations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
The Mott-Hubbard metal-insulator transition is a paradigmatic phenomenon where Coulomb interactions between electrons drive a metal-insulator phase transition. It has been extensively studied within the Hubbard model, where a quantum critical transition occurs at a finite temperature second-order critical point. This work investigates the Mott metal-insulator transition in a modified periodic Anderson model that may be viewed as a three-orbital lattice model including an interacting, localized orbital coupled to a delocalized conduction orbital via a second conduction orbital. This model could also be viewed as a bilayer model involving a conventional periodic Anderson model layer coupled to a metallic layer. Within the dynamical mean field theory, this model possesses a strictly zero temperature quantum critical point separating a Fermi liquid and a Mott insulating phase. By employing a simplified version of the dynamical mean field theory, namely, the two-site or linearized dynamical mean field theory, we provide an analytical estimate of the critical parameter strengths at which the transition occurs at zero temperature. We also provide an analytical estimate of the single-site von Neumann entanglement entropy. This measure can be used as a robust identifier for the phase transition. We extend these calculations to their cluster version to incorporate short-range, non-local spatial correlations and discuss their effects on the transition observed in this model.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 8 figures, 3 appendices
Crystal Nucleation Kinetics and Mechanism: Influence of Interaction Potential
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Porhouy Minh, Steven W. Hall, Ryan S. DeFever, Sapna Sarupria
Modulating liquid-to-solid transitions and the resulting crystalline structure for tailored properties is much desired. Colloidal systems are exemplary to this end, but the fundamental knowledge gaps in relating the influence of intermolecular interactions to crystallization behavior continue to hinder progress. In this study, we address this knowledge gap by studying nucleation and growth in systems with modified Lennard-Jones potential. Specifically, we study the commonly used 12-6 potential and a softer 7-6 potential. The thermodynamic state point for the study is chosen such that both systems are investigated at the same level of supercooling and pressure. Under these conditions, we find that the nucleation rate for both systems is comparable. Interestingly, the nucleation pathways and resulting crystal structures are different. In the 12-6 system, nucleation and growth occur predominantly through the FCC structure. Softening the potential alters the critical nucleus composition and introduces two distinct nucleation pathways. One pathway predominantly leads to the nucleus with a body-centered cubic (BCC) structure, while the other favors the face-centered cubic (FCC) arrangement. Our study illustrates that polymorph selection can be achieved through modifications to intermolecular interactions without impacting nucleation kinetics. The results have significant implications in designing approaches for polymorph selection and modulating self-assembly mechanisms.
Statistical Mechanics (cond-mat.stat-mech)
67 pages, 30 figures
Flat Midgap Topological Surface and Hypersurface Bands without Parameter Tuning
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
The Su-Schrieffer-Heeger model is extended to the three and higher dimensional systems. Nearly or absolutely flat midgap surface and hypersurface bands are predicted based on the topological analysis, which do not require fine tuning of parameters. By adding the on-site Coulomb interaction for the three dimensional systems, we computationally show that the large difference in the band widths between the surface and the bulk leads to the strongly correlated phenomena, specifically magnetism, confined only on the surface. Possible experimental realizations in solid state materials and metamaterials are discussed.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
About 4 pages of main text (excluding the reference list) and 4 pages of supplemental material
Optimizing Time-resolved Magneto-optical Kerr Effect for High-fidelity Magnetic Characterization
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Yun Kim, Dingbin Huang, Deyuan Lyu, Haoyue Sun, Jian-Ping Wang, Paul A. Crowell, Xiaojia Wang
Spintronics has emerged as a key technology for fast and non-volatile memory with great CMOS compatibility. As the building blocks for these cutting-edge devices, magnetic materials require precise characterization of their critical properties, such as the effective anisotropy field ($ H_{\rm{k,eff}}$ , related to magnetic stability) and damping ($ \alpha$ key factor in device energy efficiency). Accurate measurements of these properties are essential for designing and fabricating high-performance spintronic devices. Among advanced metrology techniques, Time-resolved Magneto-Optical Kerr Effect (TR-MOKE) stands out for its superb temporal and spatial resolutions, surpassing traditional methods like ferromagnetic resonance (FMR). However, the full potential of TR-MOKE has not yet been fully pledged due to the lack of systematic optimization and robust operational guidelines. In this study, we address this gap by developing experimentally validated guidelines for optimizing TR-MOKE metrology across materials with perpendicular magnetic anisotropy (PMA) and in-plane magnetic anisotropy (IMA). Our work identifies the optimal ranges of the field angle to simultaneously achieve high signal amplitudes and improve measurement sensitivities to $ H_{\rm{k,eff}}$ and $ \alpha$ . By suppressing the influence of inhomogeneities and boosting sensitivity, our work significantly enhances TR-MOKE capability to extract magnetic properties with high accuracy and reliability. This optimization framework positions TR-MOKE as an indispensable tool for advancing spintronics, paving the way for energy-efficient and high-speed devices that will redefine the landscape of modern computing and memory technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Submitted to Appl. Phys. Lett. Manuscript: 16 pages, 5 figures; Supplementary Materials: 18 pages, 12 figures
Magnetoelastic dynamics of the “spin Jahn-Teller” transition in CoTi${2}$O${5}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
K. Guratinder, R. D. Johnson, D. Prabhakaran, R. A. Taylor, F. Lang, S. J. Blundell, L. S. Taran, S. V. Streltsov, T. J. Williams, S. R. Giblin, T. Fennell, K. Schmalzl, C. Stock
CoTi$ _{2}$ O$ _{5}$ has the paradox that low temperature static magnetic order is incompatible with the crystal structure owing to a mirror plane that exactly frustrates magnetic interactions. Despite no observable structural distortion with diffraction, CoTi$ _{2}$ O$ {5}$ does magnetically order below $ T{\rm N}$ $ \sim$ 25 K with the breaking of spin ground state degeneracy proposed to be a realization of the spin Jahn-Teller effect in analogy to the celebrated orbital Jahn-Teller transition. We apply neutron and Raman spectroscopy to study the dynamics of this transition in CoTi$ _{2}$ O$ _{5}$ . We find anomalous acoustics associated with a symmetry breaking strain that characterizes the spin Jahn-Teller transition. Crucially, the energy of this phonon coincides with the energy scale of the magnetic excitations, and has the same symmetry of an optic mode, observed with Raman spectroscopy, which atypically softens in energy with decreasing temperature. Taken together, we propose that the energetics of the spin Jahn-Teller effect in CoTi$ _{2}$ O$ _{5}$ are related to cooperative magnetoelastic fluctuations as opposed to conventional soft critical dynamics which typically drive large measurable static displacements.
Strongly Correlated Electrons (cond-mat.str-el)
to be published in Physical Review Letters
Observation of a spin-textured nematic Kondo lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Yu-Xiao Jiang, Zi-Jia Cheng, Qiaozhi Xu, Md Shafayat Hossain, Xian P. Yang, Jia-Xin Yin, Maksim Litskevich, Tyler A. Cochran, Byunghoon Kim, Eduardo Miranda, Sheng Ran, Rafael M. Fernandes, M. Zahid Hasan
The Kondo lattice mode, as one of the most fundamental models in condensed matter physics, has been employed to describe a wide range of quantum materials such as heavy fermions, transition metal dichalcogenides and two-dimensional Moire systems. Discovering new phases on Kondo lattice and unveiling their mechanisms are crucial to the understanding of strongly correlated systems. Here, in a layered Kondo magnet USbTe, we observe a spin-textured nematic state and visualize a heavy electronic liquid-crystal phase. Employing scanning tunneling microscopy and spectroscopy (STM/STS), we visualize a tetragonal symmetry breaking of heavy electronic states around the Fermi level. Through systematically investigating the temperature and energy dependence of spectroscopic data, we find that the nematic state coincides with the formation of heavy quasi-particles driven by band hybridization. Remarkably, using spin polarized STM, we demonstrate that the nematic state is spin polarized, which not only suggests its intrinsically electronic nature, but also represents the unique magnetic texture of nematic heavy fermions. Our findings unveil a novel correlation-mediated order whose mechanism is inherently tied to Kondo-lattice physics. The observation of heavy nematic states enriches the phase diagram of correlated systems and provides a rare platform to explore the interplay of Kondo physics, spontaneous symmetry breaking and quantum criticality.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
A unifying perspective on measuring transient planar extensional viscosity from exponential shear
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
L.A. Kroo, R.A. Nicholson, M.W Boehm, S.K. Baier, G.H. McKinley
Here we present an experimentally practical and robust method to compute the transient extensional viscosity from exponential shear on a wide variety of viscoelastic complex fluids. To achieve this, we derive an analytical, frame-invariant continuum solution for the exponential shear material function, valid over all Weissenberg numbers. Specifically, we amend the original framework of Doshi and Dealy proposed in 1987 to explicitly address the effect of rotation of material elements, due to the presence of vorticity. Modern strain-controlled rheometers can access a wide range of effective Hencky strain rates in exponential shear (approximately within a range of 0.01 to 7 s^-1) and up to an effective Hencky strain of approximately 6 – sufficient range to observe finite extensibility for many polymeric fluids. We quantify the kinematic, transducer-based, and instability-related experimental limitations of the method, establishing firm windows of data validity.
The new material function is tested on a number of different example fluids. We show that these exponentially increasing strain histories are capable of producing “strong flow” – generating stress-growth dynamics consistent with coil-stretch conformational changes in polymer solutions exhibited in extensional flows (Wi > 0.5). We then demonstrate that the method can reach finite extensibility for a 0.3 % wt. PIB solution. The method is then quantitatively validated (with no fitted parameters) against a traditional extensional technique, Capillary Break-Up Extensional Rheometry (CaBER) using the same PIB solution. Questions related to generality of this approach are addressed, including discussions on multi-mode relaxation and shear thinning.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
XHEMTs on Ultrawide Bandgap Single-Crystal AlN Substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Eungkyun Kim, Yu-Hsin Chen, Naomi Pieczulewski, Jimy Encomendero, David Anthony Muller, Debdeep Jena, Huili Grace Xing
AlN has the largest bandgap in the wurtzite III-nitride semiconductor family, making it an ideal barrier for a thin GaN channel to achieve strong carrier confinement in field-effect transistors, analogous to silicon-on-insulator technology. Unlike SiO$ _2$ /Si/SiO$ _2$ , AlN/GaN/AlN can be grown fully epitaxially, enabling high carrier mobilities suitable for high-frequency applications. However, developing these heterostructures and related devices has been hindered by challenges in strain management, polarization effects, defect control and charge trapping. Here, the AlN single-crystal high electron mobility transistor (XHEMT) is introduced, a new nitride transistor technology designed to address these issues. The XHEMT structure features a pseudomorphic GaN channel sandwiched between AlN layers, grown on single-crystal AlN substrates. First-generation XHEMTs demonstrate RF performance on par with the state-of-the-art GaN HEMTs, achieving 5.92 W/mm output power and 65% peak power-added efficiency at 10 GHz under 17 V drain bias. These devices overcome several limitations present in conventional GaN HEMTs, which are grown on lattice-mismatched foreign substrates that introduce undesirable dislocations and exacerbated thermal resistance. With the recent availability of 100-mm AlN substrates and AlN’s high thermal conductivity (340 W/m$ \cdot$ K), XHEMTs show strong potential for next-generation RF electronics.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Crystal Growth of Chalcogenides and Oxy-Chalcogenides Using Chloride Exchange Reaction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Shantanu Singh, Boyang Zhao, Christopher E. Stevens, Mythili Surendran, Tzu-Chi Huang, Bi-Hsuan Lin, Joshua R. Hendrickson, Jayakanth Ravichandran
Chalcogenides and oxy-chalcogenides, including complex chalcogenides and transition metal dichalcogenides, are emerging semiconductors with direct or indirect band gaps within the visible spectrum. These materials are being explored for various photonic and electronic applications, such as photodetectors, photovoltaics, and phase-change electronics. Understanding the fundamental properties of these materials is crucial for optimizing their functionalities. Therefore, the availability of large, high-quality single crystals of chalcogenides and oxy-chalcogenides is essential for a better comprehension of their structure and properties. In this study, we present a novel crystal growth method that utilizes the exchange reaction between BaS and ZrCl$ _4$ / HfCl$ _4$ . By carefully controlling the stoichiometric ratio of the binary sulfide to the chloride, we can grow single crystals of several materials, such as ZrS$ _2$ , HfS$ _2$ , BaZrS$ _3$ , and ZrOS. This method results in large single crystals with a short reaction time of 24 to 48 hours. High-resolution thin film diffraction and single-crystal X-ray diffraction confirm the quality of the crystals produced through this exchange reaction. We also report the optical properties of these materials investigated using photoluminescence and Raman measurements. The chloride exchange reaction method paves the way for the synthesis of single crystals of chalcogenides and oxy-chalcogenide systems with a short reaction time but with low mosaicity and can be an alternative growth technique for single crystals of materials that are difficult to synthesize using conventional growth techniques.
Materials Science (cond-mat.mtrl-sci)
Quaternionic description of semiconductor position-based qubits
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Wojciech Nowakowski, Krzysztof Pomorski
The quaternionic description of semiconductor single-electron devices is given in the single-electron regime. The conversion scheme of complex value Hamiltonian into a quaternion is formulated for the case of single-electron semiconductor qubit and many electrostatically interacting qubits. In particular, the quantum evolution operator is presented in quaternion form for the case of one and many electrostatically interacting quantum bodies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 3 figures
Mean-field and Monte Carlo Analysis of Multi-Species Dynamics of agents
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Eduardo Velasco Stock, Roberto da Silva, Sebastian Gonçalves
We propose a mean-field (MF) approximation for the recurrence relation governing the dynamics of $ m$ species of particles on a square lattice, and we simultaneously perform Monte Carlo (MC) simulations under identical initial conditions to emulate the intricate motion observed in environments such as subway corridors and scramble crossings in large cities. Each species moves according to transition probabilities influenced by its respective static floor field and the state of neighboring cells. To illustrate the methodology, we analyze statistical fluctuations in the spatial distribution for $ m = 1$ , $ m = 2$ , and $ m = 4$ and for different regimes of average density and biased movement. A numerical comparison is conducted to determine the best agreement between the MC simulations and the MF approximation considering a renormalization exponent $ \beta$ that optimizes the fit between methods. Finally, we report a phenomenon we term “Gaussian-to-Gaussian” behavior, in which an initially normal distribution of particles becomes distorted due to interactions among same and opposing species, passes through a transient regime, and eventually returns to a Gaussian-like profile in the steady state, after multiple rounds of motion under periodic boundary conditions.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph), Physics and Society (physics.soc-ph)
20 pages, 7 figures
Rotating Quantum Droplets in Low Dimensions
New Submission | Other Condensed Matter (cond-mat.other) | 2025-06-23 20:00 EDT
Kevin Hernández, Elías Castellanos
Quantum droplets formed by rubidium, lithium, and sodium atoms have been analyzed in this paper by using a logarithmic-type Gross-Pitaevskii equation. Variational methods and numerical techniques were employed to solve the corresponding nonlinear equations. A disk-shaped Bose-Einstein condensate was analyzed to assess its radial evolution. Additionally, free expansion under rotation of the BEC was studied. Compression and expansion around the equilibrium radius were observed in different scenarios, predicting self-confinement, which implies the formation of quantum droplets originating from a BEC state. Briefly, the physical aspects of the system and the possible formation of Bose-nova effects are discussed.
Other Condensed Matter (cond-mat.other)
21 pages, 10 figures
Symmetry-breaking motility of an active hinge in a crowded channel
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Leonardo Garibaldi Rigon, Yongjoo Baek
A recent experiment [Son et al., Soft Matter, 2024, 20,2777-2788] showed that self-propelled particles confined within a circular boundary filled with granular medium spontaneously form a motile cluster that stays on the boundary. This cluster exhibits persistent (counter)clockwise motion driven by symmetry breaking, which arises from a positive feedback between the asymmetry of the cluster and those of the surrounding granular medium. To investigate this symmetry-breaking mechanism in broader contexts, we propose and analyze the dynamics of an active hinge moving through a crowded two-dimensional channel. Through extensive numerical simulations, we find that the lifetime of the hinge’s motile state varies nonmonotonically with both the packing fraction of the granular medium and the strength of self-propulsion. Furthermore, we observe an abrupt transition in the configuration of passive particles that sustain hinge motility as the hinge’s maximum angle relative to the channel wall increases. These findings point to the possibility of designing superstructures composed of passive granular media doped with a small number of active elements, whose dynamics modes can be switched by tuning the properties of their components.
Soft Condensed Matter (cond-mat.soft)
8 pages, 12 figures
A Kaleidoscope of Topological Structures in Dipolar Bose-Einstein Condensates with Weyl-Like Spin-Orbit Coupling in Anharmonic Trap
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Dipole-dipole interaction (DDI) possesses characteristics different from the conventional isotropic s-wave interaction in Bose-Einstein condensates (BECs), the interplay of DDI with spin-orbit coupling (SOC) and rotation may induce novel quantum properties. We systematically analyze the effects of the DDI, Weyl-like SOC, rotation and trap anharmonicity in the ground state of two-componen BECs. The interplay of these factors leads to a kaleidoscope of quantum states of quantum defects and quantum droplets in lattice, wheel and ring forms of distributions, with transitions of topology of density and a critical behavior in varying the parameters. We also show a bunch of exotic spin topological structures, including centric vortex surrounded by layers of spin flows, compound topological structure of edge defect, and various coexistence states of skyrmions with different topological charge. In particular, we find quarter skyrmions and other possible fractional skyrmions. Rashba-type SOC and Weyl-like SOC are compared as well. Our study implies that one can manipulate both the density topology and the spin topological structure via these tunable parameters in BECs. The abundant variations of the topological structures and particularly the revealed critical behavior may provide various quantum resources for potential applications in quantum metrology.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
11 pages, 7 figures
Measuring Cyclic Tensile Properties of Fluids with Composite Harmonic Exponential Waveforms (CHEW)
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
L.A. Kroo, R.A. Nicholson, M.W Boehm, S.K. Baier, P.A. Underhill, G.H. McKinley
Building off recent advances on how to practically use exponential shear in a torsional rheometer to compute transient planar extensional viscosity (Kroo et al. 2025a), we extend the technique to cyclic tensile measurements in complex fluids and soft solids. An novel input strain waveform provides a unifying approach that smoothly interpolates between exponential shear (ES) and oscillatory shear (SAOS/MAOS/LAOS) as a flow type parameter is varied. Analogous to cyclic tensile fatigue tests in solids, or the process of chewing in the oral cavity, this complex strain history is used to quantify the evolution of extensional material properties at large strains over sequential cycles of stretch. In the limit of large Hencky strain rates, the waveform locally increases exponentially and generates a period of strong material stretching. This allows for the direct computation of a transient planar extensional viscosity within specific domains of the periodic function. We demonstrate this technique on a set of model fluids, and then apply it to complex multiphase materials that mutate. These latter fluids exhibit progressive evolution in their rheological properties over repeated cycles of extensional deformation. Here we focus on two examples: a delicate foodstuff material (melted provolone cheese) which systematically decreases its extensional response over successive stretching cycles, mutating at a rate that is directly dependent on the effective Hencky strain rate. We contrast this with a PVA-borax solution which exhibits precisely the opposite effect during successive stretching cycles: increasing its planar extensional response over successive cycles, as interchain associative interactions (controlled via stretching) build structure within the fluid. These results highlight a promising new approach to study bulk extensional properties during cyclical stretching of complex fluids.
Soft Condensed Matter (cond-mat.soft)
Giant Magneto-Optical Effects in Two-Dimensional Flat-Band Antiferromagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Ping Yang, Wanxiang Feng, Siyuan Liu, Shan Guan, Liwei Wen, Wei Jiang, Gui-Bin Liu, Yugui Yao
In this work, we reveal giant magneto-optical responses in two-dimensional(2D) antiferromagnets with nearly flat electronic bands, based on first-principles calculations and group-theoretical analysis. We identify a record-large second-order magneto-optical Schafer-Hubert(SH) effect, featuring a polarization rotation angle of 28 degree, in monolayer antiferromagnetic RuOCl2, driven by flatband-enhanced interband optical transitions. Both the valence and conduction bands exhibit pronounced directional flatness, giving rise to highly anisotropic optical absorption and broadband hyperbolic frequency windows spanning the entire visible spectrum. This anisotropy leads to an exceptionally strong linear dichroism (LD) reaching 50%, far exceeding values reported in other 2D magnetic systems. Remarkably, the giant SH effect and LD appear at distinct photon energies, reflecting a momentum-direction-dependent crossover between flat and dispersive bands. Both responses are further amplified with increasing RuOCl2 film thickness. Our results establish flat-band antiferromagnets as a fertile platform for realizing giant nonlinear magneto-optical effects and open new avenues for 2D opto-spintronic device applications.
Materials Science (cond-mat.mtrl-sci)
6 pages, 3 figures
Negative capacitance overcomes Schottky-gate limits in GaN high-electron-mobility transistors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Asir Intisar Khan, Jeong-Kyu Kim, Urmita Sikder, Koushik Das, Thomas Rodriguez, Rohith Soman, Srabanti Chowdhury, Sayeef Salahuddin
For high-electron-mobility transistors based on two-dimensional electron gas (2DEG) within a quantum well, such as those based on AlGaN/GaN heterostructure, a Schottky-gate is used to maximize the amount of charge that can be induced and thereby the current that can be achieved. However, the Schottky-gate also leads to very high leakage current through the gate electrode. Adding a conventional dielectric layer between the nitride layers and gate metal can reduce leakage; but this comes at the price of a reduced drain current. Here, we used a ferroic HfO2-ZrO2 bilayer as the gate dielectric and achieved a simultaneous increase in the ON current and decrease in the leakage current, a combination otherwise not attainable with conventional dielectrics. This approach surpasses the conventional limits of Schottky GaN transistors and provides a new pathway to improve performance in transistors based on 2DEG.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Machine Learning Potentials for Alloys: A Detailed Workflow to Predict Phase Diagrams and Benchmark Accuracy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Siya Zhu, Doguhan Sariturk, Raymundo Arroyave
High-entropy alloys (HEAs) have attracted increasing attention due to their unique structural and functional properties. In the study of HEAs, thermodynamic properties and phase stability play a crucial role, making phase diagram calculations significantly important. However, phase diagram calculations with conventional CALPHAD assessments based on experimental or ab-initio data can be expensive. With the emergence of machine-learning interatomic potentials (MLIPs), we have developed a program named PhaseForge, which integrates MLIPs into the Alloy Theoretic Automated Toolkit (ATAT) framework using our MLIP calculation library, MaterialsFramework, to enable efficient exploration of alloy phase diagrams. Moreover, our workflow can also serve as a benchmarking tool for evaluating the quality of different MLIPs.
Materials Science (cond-mat.mtrl-sci)
Omnidirectionally manipulated skyrmions in an orientationally chiral system
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Jiahao Chen, Wentao Tang, Xingzhou Tang, Yang Ding, Jie Ni, Yuxi Chen, Bingxiang Li, Rui Zhang, Juan de Pablo, Yanqing Lu
Skyrmions, originally from condensed matter physics, have been widely explored in various physical systems, including soft matter. A crucial challenge in manipulating topological solitary waves like skyrmions is controlling their flow on demand. Here, we control the arbitrary moving direction of skyrmions in a chiral liquid crystal system by adjusting the bias of the applied alternate current electric field. Specifically, the velocity, including both moving direction and speed can be continuously changed. The motion control of skyrmions originates from the symmetry breaking of the topological structure induced by flexoelectric-polarization effect. The omnidirectional control of topological solitons opens new avenues in light-steering and racetrack memories.
Soft Condensed Matter (cond-mat.soft)
Non-collinear magnetism contra frustration: Magnetic order and anisotropy in hexagonal MnPtGa
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Gerhard H. Fecher, Roshnee Sahoo, Claudia Felser
MnPtGa is a hexagonal intermetallic compound with a rich variety of magnetic order. Its magnetic state is reported to range from collinear ferromagnetism, to non-collinear skyrmion type order. MnPtGa is a system with strongly localized magnetic moments at the Mn atoms as was demonstrated using calculations for disordered local moments. The magnetic moments at the Mn sites stay at about 3.9 bohr even above the calculated magnetic transition temperatures (TN = 220 K or TC = 285 K). In the present work, a special emphasis was focused on the possible non-collinear magnetic order using first principles calculations. The investigations included magnetic anisotropy, static noncollinear order in form of spin canting and dynamic non-collinearity in spin spirals. It is found that the energy differences between ferromagnetic, antiferromagnetic, canted, or spiral magnetic order are in the order of not more than 30 meV, which is in the order of thermal energies at ambient temperature. This hints that a particular magnetic state - including skyrmions, antiskyrmions or spin glass transitions - may be forced when an external field is applied at finite temperature.
Materials Science (cond-mat.mtrl-sci)
Topological characterization of magnon-polaron bands and thermal Hall conductivity in a frustrated kagome antiferromagnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Shreya Debnath, Kuntal Bhattacharyya, Saurabh Basu
Spin-phonon coupling and its efficacy in inducing multiple topological phase transitions in a frustrated kagome antiferromagnet have not been addressed in the literature. To this end, we study the ramifications of invoking optical phonons in a non-collinear antiferromagnet via two different kinds of coupling mechanisms, namely, a local and a non-local one, which are distinct in their macroscopic origin. In the case of a local spin-phonon coupling, a single phonon mode affects the magnetic interactions, whereas in the non-local case, two neighbouring phonon modes are involved in the energy renormalization, and it would be worthwhile to compare and contrast the two. To tackle these phonons, we propose an analytical approach through a canonical spin-Peierls transformation applied to magnons, that renders a hybridization between the magnons and the phonon modes and yields a magnon-polaron quasiparticle state. In both the coupling regimes, the robust support of the topological signatures is derived systematically from the bulk and edge spectral properties of the magnon-polaron bands that are characterized by their corresponding Chern numbers. Thereafter, we witness transitions from one topological phase to another solely via tuning the spin-phonon coupling strength. Moreover, these transitions significantly impact the behavior of the thermal Hall conductivity, which aid in discerning distinct topological phases. Additionally, the explicit dependencies on the temperature and the external magnetic field are explored in inducing topological phase transitions associated with the magnon-polaron bands. Thus, our work serves as an ideal platform to probe the interplay of frustrated magnetism and polaronic physics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
20 pages, 12 figures. Comments are welcome
Electron-phonon coupling in Kekulé-ordered graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Breaking the intrinsic chirality of quasiparticles in graphene enables the emergence of new and intriguing phases. One such paradigmatic example is the bond density wave, which leads to a Kekulé-ordered structure and underpins exotic electronic states where electron-phonon interactions can play a fundamental role. Here, it is shown that the relevant physics of these correlations can be resolved locally, according to the behavior of interatomic characteristics. For this purpose a robust distance-dependent framework for describing electronic structure of graphene with Kekulé bond order is presented. Given this insight, the strength of electron-phonon interactions is found to scale linearly with the electronic coupling, contributing to a uniform picture of this relationship in distorted graphene structures. Moreover, it is shown that the introduced distortion yields a strongly non-uniform spatial distribution of the pairing strength that eventually leads to the induction of periodically distributed domains of enhanced electron-phonon coupling. These findings help elucidate certain peculiar aspects of phonon-mediated phenomena in graphene, particularly the associated superconducting phase, and offer potential pathways for their further engineering.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
7 pages, 4 figures
Effective Field Theory of a Noncollinear Altermagnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
We derive an effective field theory for a noncollinear altermagnet and magnons on top of the noncollinear ground state from an altermagnetic Heisenberg model. We obtain the ground-state phase diagram, revealing a noncollinear phase and four distinct collinear phases. The ground state of the noncollinear phase fully breaks the spin rotational symmetry, while the ground state of the collinear phases possesses unbroken $ \mathrm{SO}(2)$ symmetry. The resulting effective field theory for the noncollinear phase is an $ \mathrm{SO}(3)$ sigma model in which the magnonic excitation has three independent degrees of freedom and exhibits the $ d$ -wave-like anisotropic linear dispersion. We also discuss possible topological solitons, including $ \mathbb{Z}_2$ vortices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
17 pages, 4 figures
Double Supersolid Phase in a Bosonic t-J-V Model with Rydberg Atoms
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Kuangjie Chen, Yang Qi, Zheng Yan, Xiaopeng Li
Recent advances in Rydberg tweezer arrays bring novel opportunities for programmable quantum simulations beyond previous capabilities. In this work, we investigate a bosonic t-J-V model currently realized with Rydberg atoms. Through large-scale quantum Monte Carlo simulations, we uncover an emergent double supersolid (DSS) phase with the coexistence of two superfluids and crystalline order. Tunable long-range tunneling and repulsive hole-hole interactions enable a rich phase diagram featuring a double superfluid phase, a DSS phase, and an antiferromagnetic insulator. Intriguingly, within the DSS regime we observe an unconventional thermal enhancement of crystalline order. Our results establish the bosonic t-J-V model as a promising and experimentally accessible platform for exploring exotic quantum phases in Rydberg atom arrays.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 5 figures
Hop-Decorate: An Automated Atomistic Workflow for Generating Defect Transport Data in Chemically Complex Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Peter Hatton, Blas Pedro Uberuaga, Danny Perez
Chemically complex materials (CCMs) exhibit extraordinary functional properties but pose significant challenges for atomistic modeling due to their vast configurational heterogeneity. We introduce Hop-Decorate (HopDec), a high-throughput, Python-based atomistic workflow that automates the generation of defect transport data in CCMs. HopDec integrates accelerated molecular dynamics with a novel redecoration algorithm to efficiently sample migration pathways across chemically diverse local environments. The method constructs a defect-state graph in which transitions are associated with distributions of kinetic and thermodynamic parameters, enabling direct input into kinetic Monte Carlo and other mesoscale models. We demonstrate HopDec’s capabilities through applications to a Cu-Ni alloy and the spinel oxide (Fe,Ni)Cr2O4, revealing simple predictive relationships in the former and complex migration behaviors driven by cation disorder in the latter. These results highlight HopDec’s ability to extract physically meaningful trends and support reduced-order or machine-learned models of defect kinetics, bridging atomic-scale simulations and mesoscale predictions in complex material systems.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Local symmetry breaking and orbital glass behaviour in CoFe2O4
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Soumya Shephalika Behera, Isha, Arvind Kumar Yogi, V R Rao Medicherla, Parasmani Rajput, Archana Sagdeo, Jaspreet Singh, Vasant Sathe, R J Choudhary
The structural distortions, orbital correlations, and electronic states in cobalt ferrite (CoFe2O4) were investigated using complementary characterisation techniques, including SR-XRD, HAXPES, XANES, EXAFS, and Raman spectroscopy. SR-XRD confirms phase purity and reveals a temperature-dependent superlattice reflection between 200 K and 100 K, consistent with the emergence of short-range orbital ordering driven by cooperative Jahn-Teller distortion (JTD). The disappearance of this feature below 100 K signals orbital freezing and the onset of a glass-like orbital state. HAXPES measurements show multiplet splitting and charge-transfer satellite features in the Co and Fe 2p core levels, indicating mixed valence states and strong electron correlations. XANES analysis reveals hybridized p-d states and local coordination distortions. Temperature-dependent EXAFS measurements indicate increasing local disorder-particularly in Fe-O and Fe-Fe octahedral bonds as evidenced by enhanced Debye-Waller factors. These distortions, attributed to cation redistribution and oxygen vacancies, are static and asymmetric, primarily affecting the octahedral sublattice. Notably, signatures of cooperative Jahn-Teller distortions emerge in the intermediate temperature range (200-100 K) and disappear upon further cooling. Raman spectroscopy further supports these findings, revealing phonon anomalies and enhanced spin-phonon coupling in the same temperature range. Magnetic measurements indicate spin reorientation and exchange interaction anomalies that align with the orbital behaviour. Together, these results hint at a frustrated orbital state in CoFe2O4 possibly involving cooperative Jahn-Teller distortions, disrupted long-range coherence, and orbital glass behaviour offering new insights into the coupling of orbital, spin, and lattice degrees of freedom in spinel systems.
Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 13 fugures, 3 tables
An investigation of the two-dimensional non-Hermitian Su-Schrieffer-Heeger Model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Udai Prakash Tyagi, Partha Goswami
This communication presents an examination of a two-dimensional, non-Hermitian Su -Schrieffer-Heeger (SSH) model, which is differentiated from its conventional Hermitian counterpart by incorporating gain and/or loss terms, mathematically represented by imaginary on-site potentials. The time-reversal symmetry is disrupted due to these on-site potentials. Exceptional points in a non-Hermitian system feature eigenvalue coalescence and non-trivial eigenvector degeneracies. Utilization of the rank-nullity theorem and graphical analysis of the phase rigidity factor enable identification of true exceptional points. Furthermore, this investigation achieves vectorized Zak phase quantization and examines a topolectric RLC circuit to derive the corresponding topological boundary resonance condition and the quantum Hall susceptance. Although Chern number quantization is not feasible, staggered hopping amplitudes corresponding to unit-cell lattice sites lead to broken inversion symmetry with non-zero Berry curvature, resulting in finite anomalous Nernst conductivity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
25 pages, 6 Figures
Spin-polarized edge modes between different magnet-superconductor-hybrids
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Felix Zahner, Felix Nickel, Roberto Lo Conte, Tim Drevelow, Roland Wiesendanger, Stefan Heinze, Kirsten von Bergmann
The interplay of magnetism and superconductivity can lead to intriguing emergent phenomena. Here we combine two different two-dimensional antiferromagnetic magnet-superconductor hybrids (MSH) and study their properties using spin-polarized scanning tunneling microscopy. Both MSHs show the characteristics of a topological nodal point superconducting phase with edge modes to the trivial substrate superconductor. At the boundary between the two MSHs we find low-energy modes which are spin-polarized. Based on a tight-binding model we can explain the experimental observations by considering two different topological nodal point superconductors. This gives rise to spin-polarized chiral edge modes that connect topological nodal points of the two different MSH. We demonstrate via the complex band structure that due to an asymmetric lateral decay these edge modes are spin-polarized, regardless of the details of the spin structure at the boundary. The presence of spin-polarized edge states between different topological superconductors enables advanced functional design for the exploitation of MSHs as a platform for topology-based applications.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
12 pages, 9 figures
Optical signatures of quantum skyrmions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Sanchar Sharma, Christina Psaroudaki
Magnets have recently emerged as promising candidates for quantum computing, particularly using topologically-protected nanoscale spin textures. While the quantum dynamics of such spin textures has been theoretically studied, direct experimental evidence of their non-classical behavior remains an open challenge. To address this, we propose to employ Brillouin light scattering (BLS) as a method to probe the quantum nature of skyrmions in frustrated magnets. We show that, for a specific geometry, classical skyrmions produce symmetric sidebands in the BLS spectrum, whereas quantum skyrmions exhibit a distinct asymmetry arising from vacuum fluctuations of their rotation. By studying the photon-skyrmion interaction, we calculate the BLS spectrum using a quantum master equation and show that sideband asymmetry serves as a robust witness of energy level quantization. We find that this asymmetry is pronounced at low temperatures, and can be controlled by input laser power. These findings establish a concrete protocol for the optical detection of non-classical features in spin textures, paving the way for exploring their role in quantum applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Winding-Control Mechanism of Non-Hermitian Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Non-Hermitian quantum systems exhibit various interesting and inter-connected spectral, topological, and boundary-sensitive features. By introducing conditional boundary conditions (CBCs) for non-Hermitian quantum systems, we explore a winding-control mechanism that selectively collapses specific periodic boundary condition (PBC) spectra onto their open boundary condition (OBC) counterparts, guided by their specific winding numbers, together with a composite reconstruction of the Brillouin zone (BZ) and generalized Brillouin zone (GBZ). The corresponding eigenstates also manifest nontrivial skin effects or extended behaviors arising from the interplay between BZ and GBZ structures. Furthermore, we can generalize our control by incorporating similarity transformations and holomorphic mappings with the boundary controls. We demonstrate the winding control numerically within various models, which enriches our knowledge of non-Hermitian physics across the spectrum, topology, and bulk-boundary correspondence.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 10 figures
A Josephson wormhole in coupled superconducting Yukawa-SYK metals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Aravindh S. Shankar, Jasper Steenbergen, Stephan Plugge, Koenraad Schalm
We show that two Yukawa-SYK models with a weak tunneling contact can have an exotic hybrid superconducting thermofield-double-like state that is holographically dual to a traversable wormhole connecting two black holes with charged scalar hair. The hybrid superconducting thermo-field-double/wormhole state is distinguishable by anomalous scaling of revival oscillations in the fermionic Green’s function, but also in a unique Andreev-revival in the anomalous Green’s function. The existence of this TFD/wormhole state surprisingly shows that the some quantum critical effects can survive the phase transition to superconductivity. This Andreev-revival is in principle an accessible signature of the transition to the TFD/wormhole phase detectable in the ac-Josephson current.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con), High Energy Physics - Theory (hep-th)
8 pages, 8 figures, comments welcome
Single-shot thermometry of simulated Bose–Einstein condensates using artificial intelligence
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Jack Griffiths, Steven A. Wrathmall, Simon A. Gardiner
Precise determination of thermodynamic parameters in ultracold Bose gases remains challenging due to the destructive nature of conventional measurement techniques and inherent experimental uncertainties. We demonstrate an artificial intelligence approach for rapid, non-destructive estimation of the chemical potential and temperature from single-shot, in situ imaged density profiles of finite-temperature Bose gases. Our convolutional neural network is trained exclusively on quasi-2D `pancake’ condensates in harmonic trap configurations. It achieves parameter extraction within fractions of a second. The model also demonstrates zero-shot generalisation across both trap geometry and thermalisation dynamics, successfully estimating thermodynamic parameters for toroidally trapped condensates with errors of only a few nanokelvin despite no prior exposure to such geometries during training, and maintaining predictive accuracy during dynamic thermalisation processes after a relatively brief evolution without explicit training on non-equilibrium states. These results suggest that supervised learning can overcome traditional limitations in ultracold atom thermometry, with extension to broader geometric configurations, temperature ranges, and additional parameters potentially enabling comprehensive real-time analysis of quantum gas experiments. Such capabilities could significantly streamline experimental workflows whilst improving measurement precision across a range of quantum fluid systems.
Quantum Gases (cond-mat.quant-gas), Artificial Intelligence (cs.AI), Computational Physics (physics.comp-ph)
Space Group Symmetry of Chiral Fe-deficient van der Waals Magnet $\text{Fe}{\text{3-x}}\text{GeTe}{\text{2}}$ Probed by Convergent Beam Electron Diffraction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
S. Subakti (1), D. Wolf (1), O. Zaiets (1 and 2), S. Parkin (3), A. Lubk (1 and 2 and 4) ((1) Leibniz Institute for Solid State and Materials Research Dresden, Germany, (2) Institute of Solid State and Materials Physics, TU Dresden, Germany, (3) Department for Nano-Systems from Ions, Spins, and Electrons (NISE), Max Planck Institute of Microstructure Physics, Germany, (4) Würzburg–Dresden Cluster of Excellence <a href=”http://ct.qmat“ rel=”external noopener nofollow” class=”link-external link-http”>this http URL</a>, TU Dresden, Germany)
Crystal structure symmetry of Fe-deficient $ \text{Fe}{\text{2.9}}\text{GeTe}{\text{2}}$ at room temperature has been investigated by a combination of selected-area electron diffraction (SAED) and convergent-beam electron diffraction (CBED). By symmetry analysis of CBED patterns along different zone axis, the space group of $ \text{Fe}{\text{2.9}}\text{GeTe}{\text{2}}$ at room-temperature has been identified as $ P6_3mc$ (No.186), which derives from the high-symmetry parent system $ \text{Fe}{\text{3}}\text{GeTe}{\text{2}}$ ($ P6_3/mmc$ ) by breaking the mirror symmetry along the six-fold rotation axis. The $ P3m1$ (No.156) space group previously reported for $ \text{Fe}{\text{2.9}}\text{GeTe}{\text{2}}$ is a subgroup of $ P6_3mc$ suggesting further possible symmetry breaks in this non-stochiometric system.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Role of hydrogen dynamics and deposition conditions in photochromic YHO/MoO$_3$ bilayer films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Edvards Strods, Martins Zubkins, Viktors Vibornijs, Dmitrii Moldarev, Anatolijs Sarakovskis, Karlis Kundzins, Emija Letko, Daniel Primetzhofer, Juris Purans
Oxygen-containing yttrium hydride (YHO) and molybdenum trioxide (MoO$ _3$ ) bilayer films (YHO/MoO$ _3$ ) are produced using reactive magnetron sputtering, and their photochromic properties are investigated in relation to the thickness and density of the MoO$ _3$ layer. Compared to single YHO films, the YHO/MoO$ _3$ films exhibit faster coloration and larger contrast, with both parameters adjustable by varying the thickness or deposition pressure of the MoO$ _3$ layer. Transparent YHO/MoO$ _3$ films (~75% at 550 nm) demonstrate a photochromic contrast of up to 60%, significantly higher than the 25-30% contrast observed for single YHO films after 20 hours of UVA-violet light exposure. This enhancement arises from hydrogen intercalation from the (200)-textured polycrystalline YHO film into the X-ray amorphous MoO$ _3$ , leading to the formation of molybdenum bronze (HxMoO$ _3$ ), as confirmed by X-ray photoelectron and optical spectroscopies. However, the darkened YHO/MoO$ _3$ films do not fully recover to their initial transparency after illumination due to the irreversible nature of the coloured MoO$ _3$ layer. Most of the hydrogen intercalated into MoO$ _3$ originates from the YHO layer during the initial darkening process. Furthermore, the bilayer films are chemically unstable, exhibiting gradual darkening over time even without intentional UV illumination, as confirmed by nuclear reaction analysis.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
28 pages, 8 figures
Solar Energy Materials & Solar Cells 292 (2025) 113789
Band-like Exact Zero-energy Andreev Bound States and Superconducting Diode Effect in Mixed ${s+p}$-wave Josephson Junctions
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Topological Josephson junctions enable nonreciprocal transport involving Majorana fermions (MFs). Here we examine a topological Josephson junction with mixed $ s$ +$ p$ -wave pairing, where topological phase transition can be driven by adjusting the ratio between the pairing components. There exist two exact symmetrically positioned zero-energy level crossings for the Andreev-bound states, which can be shifted by external fields, and can be destroyed or recreated in pairs by a time-reversal breaking Zeeman field or inhomogeneities, exhibiting band-like structure. The dependence of the shift on the Zeeman field is linear when the two $ p$ -wave $ \boldsymbol{d}$ -vectors on both sides are identical while quadratic when they are distinct. Near the topological phase transition, the topological $ p$ -wave dominant junctions host MF-induced pronounced superconducting diode effect with high efficiency factor $ Q$ up to 30 %, in contrast to the trivial $ s$ -wave dominant junctions possessing relatively small $ Q$ .
Superconductivity (cond-mat.supr-con)
Influence of the Effective Mass on ab initio Phonon-limited Electron Mobility of GaAs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Mohammad Dehghani, Dominic Waldhoer, Angus Gentles, Pedram Khakbaz, Rainer Minixhofer, Michael Waltl
We present a comprehensive ab initio study of the influence of band structure corrections, particularly the electron effective mass, on the phonon-limited electron drift and Hall mobilities of GaAs. Our approach is based on the DFT+$ U$ method, combined with an iterative solution of the linearized Boltzmann transport equation using the Wannier interpolation technique. We show how this framework allows for accurate refinements of the electronic band structure and phonon dispersion, leading to improved predictions for transport properties. In particular, by varying the Hubbard parameters to purposefully tune the conduction band features, allowing us to reproduce bands with different electron effective mass, we systematically investigate the relationship between mobility and effective mass. In this context, our results show close agreement with semi-empirical relations that follow a power-law dependence. Moreover, this approach can be used to indirectly incorporate temperature effects into the band structure, enabling efficient evaluation of temperature-dependent electron mobilities. Our mobility results exhibit good agreement with experimental data and are comparable to previously reported values obtained using the computationally expensive GW method.
Materials Science (cond-mat.mtrl-sci)
Line Tension Reshapes Nucleation at Surface Edges: A Generalized Theory for Nanopore Activation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Yanchen Wu, Martin Z. Bazant, Allan S. Myerson, Richard D. Braatz
Heterogeneous nucleation at surface edges is pervasive across nature and industry, yet the role of line tension, arising from asymmetric capillary interactions at geometric singularities, remains poorly understood. Herein we develop a generalized nucleation theory that explicitly incorporates line tension induced by edge pinning, thereby extending classical frameworks to account for nanoscale confinement and interfacial asymmetry. Through analytical treatment of droplet formation within geometrically defined nanopores, we derive a closed-form expression for the edge-pinned line tension as a function of Laplace pressure, pore geometry, and wettability. This formulation reveals that line tension can significantly reshape the nucleation energy landscape, introducing nontrivial dependencies on contact angle and pore morphology. Our results uncover a tunable, geometry-mediated mechanism for controlling nucleation barriers, offering predictive insight into phase transitions in confined environments and suggesting new strategies for design in applications ranging from nanofluidics to crystallization control.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Nuclear Theory (nucl-th)
Probing dynamical axion quasiparticles with two-photon correlations
New Submission | Other Condensed Matter (cond-mat.other) | 2025-06-23 20:00 EDT
Dynamical axion (quasi) particles are emergent collective excitations in topological magnetic insulators that break parity and time reversal invariance or in Weyl semimetals. They couple to electromagnetism via a topological Chern-Simons term, leading to their decay into two photons. We extend the Weisskopf-Wigner formulation of atomic spontaneous emission to the quantum field theory of dynamical axion quasiparticles, allowing us to obtain the quantum two-photon state emerging from axion decay in real time. This state features \emph{hyperentanglement} in momentum and polarization with a distinct polarization pattern, a consequence of the parity and time reversal breaking of the axion-photon interaction. Polarization aspects of this two-photon state are studied by introducing quantum Stokes operators. Whereas the two-photon quantum state features vanishing \emph{averages} of the degree of polarization and polarization asymmetry, there are non-trivial momentum correlations of the Stokes operators. In particular momentum correlations of the \emph{polarization asymmetry} can be obtained directly from coincident momentum and polarization resolved two photon detection. Correlations of Stokes operators are directly related to momentum and polarization resolved Hanbury-Brown Twiss second order coherences. This relationship suggests two-photon correlations as a direct probe of dynamical axion quasiparticles. Similarities and differences with parametrically down converted photons and other systems where spontaneous emission yield hyperentangled two photon states are recognized, suggesting experimental avenues similar to tests of Bell inequalities to probe dynamical axion quasiparticles with coincident two photon detection.
Other Condensed Matter (cond-mat.other), High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
35 pages 4 figures. arXiv admin note: text overlap with arXiv:2503.04533
Simulating Correlated Electrons with Symmetry-Enforced Normalizing Flows
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-23 20:00 EDT
Dominic Schuh, Janik Kreit, Evan Berkowitz, Lena Funcke, Thomas Luu, Kim A. Nicoli, Marcel Rodekamp
We present the first proof of principle that normalizing flows can accurately learn the Boltzmann distribution of the fermionic Hubbard model - a key framework for describing the electronic structure of graphene and related materials. State-of-the-art methods like Hybrid Monte Carlo often suffer from ergodicity issues near the time-continuum limit, leading to biased estimates. Leveraging symmetry-aware architectures as well as independent and identically distributed sampling, our approach resolves these issues and achieves significant speed-ups over traditional methods.
Strongly Correlated Electrons (cond-mat.str-el), Machine Learning (cs.LG), High Energy Physics - Lattice (hep-lat)
9 pages, 7 figures
Nanosculpted 3D helices of a magnetic Weyl semimetal with switchable nonreciprocity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
Max T. Birch, Yukako Fujishiro, Ilya Belopolski, Masataka Mogi, Yi-Ling Chiew, Xiuzhen Yu, Naoto Nagaosa, Minoru Kawamura, Yoshinori Tokura
The emergent properties of materials are defined by the symmetries of their underlying atomic, spin and charge order. The explorations of symmetry breaking effects are therefore usually limited by the intrinsic properties of known, stable materials. In recent years, advances in focused ion beam (FIB) fabrication have enabled the nanostructuring of bulk crystals into ultraprecise transport devices [1-4], facilitating the investigation of geometrical effects on mesoscopic length scales. In this work, we expand such explorations into three-dimensional (3D), curvilinear shapes, by sculpting helical nanostructure devices from single crystals of the high-mobility, centrosymmetric magnetic Weyl semimetal Co$ _3$ Sn$ _2$ S$ _2$ [5,6]. The combination of the imposed chiral geometry and intrinsic ferromagnetism yields nonreciprocal electron transport [7-9]. The high coercivity results in an anomalous, reversable diode effect remnant under zero applied magnetic field, which is orders of magnitude larger than can be explained by a classical self-field mechanism. We argue the enhancement originates from the high carrier mobility and the resulting quasi-ballistic transport: the conduction electron mean free path approaches the length scale of the curvature, resulting in increased asymmetrical scattering at the boundaries. We further demonstrate the inverse effect of the nonreciprocal transport: the field-free, current-induced switching of the magnetisation. The results establish the vast potential of 3D nanosculpting to explore and enrich the functionality of quantum materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Multistability and Noise-Induced Transitions in Dispersively-Coupled Nonlinear Nanomechanical Modes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-23 20:00 EDT
David Allemeier, İsmet İnönü Kaya, M. Selim Hanay, Kamil L. Ekinci
We study the noisy dynamics of two coupled bistable modes of a nanomechanical beam. When de-coupled, each driven mode obeys the Duffing equation of motion, with a well-defined bistable region in the frequency domain. When both modes are driven, intermodal dispersive coupling emerges due to the amplitude dependence of the modal frequencies and leads to coupled states of the two modes. We map out the dynamics of the system by sweeping the drive frequencies of both modes in the presence of added noise. The system then samples all accessible states at each combination of frequencies, with the probability of each stable state being proportional to its occupancy time at steady state. In the frequency domain, the system exhibits four stable regions – one for each coupled state – which are separated by five curves. These curves are reminiscent of coexistence curves in an equilibrium phase diagram: each curve is defined by robust inter-state transitions, with equal probabilities of finding the system in the two contiguous states. Remarkably, the curves intersect in two triple points, where the system now transitions between three distinct contiguous states. A physical analogy can be made between this nonequilibrium system and a multi-phase thermodynamic system, with possible applications in computing, precision sensing, and signal processing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chaotic Dynamics (nlin.CD), Applied Physics (physics.app-ph)
A many-body characterization of the fundamental gap in monolayer CrI$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
Daniel Staros, Abdulgani Annaberdiyev, Kevin Gasperich, Anouar Benali, Panchapakesan Ganesh, Brenda Rubenstein
The many-body fixed-node and fixed-phase spin-orbit Diffusion Monte Carlo (DMC) methods are applied to accurately predict the fundamental gap of monolayer CrI$ _3$ - the first experimentally-realized 2D material with intrinsic magnetism. The fundamental gap obtained, 2.9(1)~eV, agrees well with the highest peak in optical spectroscopy measurements and a previous $ GW$ result. We numerically show that as expected in DMC the same value of the fundamental gap is obtained in the thermodynamic limit using both neutral promotions and the standard quasiparticle definition of the gap based on the ionization potential and electron affinity. Additional analysis of the differences between density matrices formed in different bases using configuration interaction calculations explains why a single-reference trial wave function can produce an accurate excitation. We find that accounting for electron correlation is more crucial than accounting for spin-orbit effects in determining the fundamental gap. These results highlight how DMC can be used to benchmark 2D material physics and emphasize the importance of using beyond-DFT methods for studying 2D materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
13 pages, 7 figures
Phase Transition of the Ising Model on a 3-Dimensional Fractal Lattice
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Jozef Genzor, Roman Krčmár, Hiroshi Ueda, Denis Kochan, Andrej Gendiar, Tomotoshi Nishino
The critical behavior of the classical Ising model on a three-dimensional fractal lattice with Hausdorff dimension $ d_H = \ln32 / \ln4 = 2.5$ is investigated using the higher-order tensor renormalization group (HOTRG) method. We determine the critical temperature $ T_c \approx 2.65231$ and the critical exponents for magnetization $ \beta \approx 0.059$ and field response $ \delta \approx 35$ . Unlike a previously studied 2D fractal with $ d_H \approx 1.792$ , the specific heat for this 3D fractal exhibits a divergent singularity at $ T_c$ . The results are compared with those for regular lattices and other fractal structures to elucidate the role of dimensionality in critical phenomena.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 5 figures, 2 tables
Electric field control of superconducting fluctuations and quasiparticle interference at oxide interfaces
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Graham Kimbell (1), Ulderico Filippozzi (2), Stefano Gariglio (1), Marc Gabay (3), Andreas Glatz (4 and 5), Andrey Varlamov (6 and 7), Andrea Caviglia (1) ((1) Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland, (2) Kavli Institute of Nanoscience, Delft University of Technology, Delft, Netherlands, (3) Laboratoire de Physique des Solides, Universite Paris Saclay, CNRS UMR 8502, Orsay Cedex, France, (4) Materials Science Division, Argonne National Laboratory, Argonne, Illinois, USA, (5) Department of Physics, Northern Illinois University, DeKalb, Illinois, USA, (6) Institute of Superconductivity and Innovative Materials (CNR-SPIN) Rome, Italy, (7) Lombard Institute ‘’Academy of Sciences and Letters’’, Milan, Italy)
We investigate tunable superconducting transitions in (111)$ \mathrm{LaAlO}_3/\mathrm{KTaO}_3$ field-effect devices. Large increases in conductivity, associated with superconducting fluctuations, are observed far above the transition temperature. However, the standard Aslamazov-Larkin paraconductivity model significantly underestimates the effect observed here. We use a model that includes conductivity corrections from normal state quasiparticle interference together with all contributions from superconducting fluctuations evaluated at arbitrary temperatures and in the short-wavelength limit. Through analysis of the magnetoconductance and resistive transitions, we find that the large conductivity increase can be explained by a combination of weak anti-localization and Maki-Thompson superconducting fluctuations. Both contributions are enabled by a strong temperature dependence of the electron’s decoherence time compatible with an electron-phonon scattering scenario. We find that conductivity corrections are modulated by the electrostatic field effect, that governs a competition between normal-state quasiparticle interference and superconducting fluctuations.
Superconductivity (cond-mat.supr-con)
Quantum droplets in rapidly rotating two-dimensional Bose-Einstein condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Zhen Cao, Siying Li, Zhendong Li, Xinyi Liu, Zhigang Wu, Mingyuan Sun
Recent experiments demonstrate that rapidly rotating Bose-Einstein condensates (BECs) near the lowest Landau level can self-organize into interaction-driven persistent droplet arrays. Inspired by this discovery, we investigate the formation and dynamics of single droplet and droplet arrays in rapidly rotating BECs. Guided by a rigorous theorem on localized many-body states for 2D interacting systems in a magnetic field, we construct single droplet and droplet arrays states which are shown to be stationary solutions to the Gross-Pitaevskii equation in the rotating frame. The single droplet is shown to be dynamically stable, which underpins its role as the basic unit in a droplet array. The stability of the droplet arrays is demonstrated by their dynamic formation from a phase engineered initial condensate. Our study sheds light onto the nature of the droplet state in a rapidly rotating BEC and offers a new approach for generating and manipulating quantum droplet arrays through designing the initial condensate phase.
Quantum Gases (cond-mat.quant-gas)
6 pages, 6 figures
Two dimensional sub-wavelength topological dark state lattices
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-23 20:00 EDT
Domantas Burba, Gediminas Juzeliūnas
We present a general framework for engineering two-dimensional (2D) sub-wavelength topological optical lattices using spatially dependent atomic dark states in a $ \Lambda$ -type configuration of the atom-light coupling. By properly designing the spatial profiles of the laser fields inducing coupling between the atomic internal states, we show how to generate sub-wavelength Kronig-Penney-like geometric scalar potential accompanied by narrow and strong patches of the synthetic magnetic field localized in the same areas as the scalar potential. These sharply peaked magnetic fluxes are compensated by a smooth background magnetic field of opposite sign, resulting in zero net flux per unit cell while still enabling topologically nontrivial band structures. Specifically, for sufficiently narrow peaks, their influence is minimum, and the behavior of the system in a remaining smooth background magnetic field resembles the Landau problem, allowing for the formation of nearly flat energy bands with unit Chern numbers. Numerical analysis confirms the existence of ideal Chern bands and the robustness of the topological phases against non-adiabatic effects and losses. This makes the scheme well-suited for simulating quantum Hall systems and fractional Chern insulators in ultracold atomic gases, offering a new platform for exploring strongly correlated topological phases with high tunability.
Quantum Gases (cond-mat.quant-gas), Other Condensed Matter (cond-mat.other), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
11 pages, 8 figures
Instabilities in Colloidal Crystals on Fluid Membranes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Sanjay Dharmavaram, Basant Lal Sharma
The complex physics of self-assembly in colloidal crystals on deformable interfaces and surfaces poses interesting possibilities for the designability and synthesis of next-generation metamaterials. The goal of this article is to characterize instabilities arising in colloidal crystals assembled on fluid membranes. The colloidal particles are modeled as pair-wise interacting point particles, constrained to lie on a fluid membrane and yet free to reorganize, and the membrane’s elastic energy is modeled via the Helfrich energy. We find that when a collection of particles is arranged on a planar membrane in some regular fashion – such as periodic lattice – then the regular configuration admits bifurcations to non-planar configurations. Using the Bloch-wave anstaz for the mode of instabilities, we present a parameteric analysis of the boundary between the stable and unstable regimes. We find that instabilities can occur through two distinct kinds of modes, when the parameters belong in certain physically interesting regimes, referred to as long-wavenumber modes ($ L$ modes) and short-wavenumber modes ($ S$ modes) in the article. We discuss some connections between these results and recent experiments, as well as the open problem of budding in biomembranes.
Soft Condensed Matter (cond-mat.soft)
21 pages
Axion electrodynamics of Weyl superconductors with broken time-reversal symmetry
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Vira Shyta, Jeroen van den Brink, Flavio S. Nogueira
The low-energy effective description of Weyl semimetals is defined by the axion electrodynamics, which captures the effects arising due to the presence of nodes of opposite chirality in the electronic structure. Here we explore the magnetoelectric response of time-reversal breaking (TRB) Weyl superconductors in the London regime. The influence of the axion contribution leads to an increase in the London penetration depth$ -$ a behavior that can be anticipated by first considering the photon spectrum of a TRB Weyl semimetal. Moreover, we find that both the Meissner state and the vortex phase feature an interplay between the electric and magnetic fields. This leads to a nonvanishing electromagnetic angular momentum, which we calculate for a number of geometrical configurations.
Superconductivity (cond-mat.supr-con), High Energy Physics - Phenomenology (hep-ph), High Energy Physics - Theory (hep-th)
12 pages, 2 figures
Quantitative correlation between structural (dis-)order and diffuseness of phase transition in lead scandium tantalate
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-23 20:00 EDT
T. Granzow, A. Aravindhan, Y. Nouchokgwe, V. Kovacova, S. Glinsek, S. Hirose, T. Usui, H. Uršič, I. Goričan, W. Jo, C.-H. Hong, E. Defay
Ferroelectrics show a phase transition to a paraelectric phase at a well-defined transition temperature. Introducing disorder makes this transition diffuse, and the system becomes a relaxor. Since the degree of (dis-)order is usually manipulated by varying the chemical composition, it is difficult to establish a direct relationship between disorder and the degree of diffuseness. Perovskite structured lead scandium tantalate (Pb[Sc$ _{1/2}$ Ta$ _{1/2}$ ]O$ _3$ , PST) offers the opportunity to tune the character of the transition by thermal annealing without changing the stoichiometry. Here it is demonstrated that there is a linear correlation between the structural ordering, quantified by the intensity ratio $ S$ of the pseudocubic (111)/(200) x-ray diffraction peaks, and the diffuseness parameter $ \gamma$ deduced from temperature-dependent dielectric spectroscopy. The relation is universal, independent of whether the sample is a thin film, multilayer capacitor or bulk ceramic, and also independent of the absolute value of the dielectric permittivity.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
12 pages, 4 figures
Cascade at local yield strain for silica and metallic glass
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-23 20:00 EDT
Nandlal Pingua, Himani Rautela, Roni Chatterjee, Smarajit Karmakar, Pinaki Chaudhuri, Shiladitya Sengupta
We report observations of unusal \emph{first} plastic events in silica and metallic glasses in the shear startup regime at applied strain two orders of magnitude smaller than yield strain. The (non-Affine) particle displacement field during these events have complex real space structure with multiple disconnected cores of high displacement appearing at the \emph{same} applied strain under athermal quasistatic simple shear deformation, and identified by a cell based cluster analysis'' method. By monitoring the stress relaxation during the first plastic event by Langevin dynamics simulation, we directly show the cascade nature of these events. Thus these first plastic events are reminiscent of avalanches in the post-yielding steady state, but unlike the steady state avalanches, we show that these events are not system spanning. To understand the nature of these events, we tune three factors that are known to affect brittleness of a glass. These are (i) sample preparation history, (ii) inter-particle interactions and (iii) rigidity of the background matrix applying a soft matrix’’ probe recently developed by some of us. In each case we show that such first plastic events are more probable in more ductile glasses. Our observations are consistent with the picture that more ductile materials are softer, implying that understanding the role of softness may be a promising route to develop microscopic quantifiers of brittleness and thus clarifying the physical origin of brittle-to-ductile transition.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
J. Chem. Phys. 162, 214504 (2025)
Unraveling the Robust Superconductivity Phenomenon of High-Entropy Alloy
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-23 20:00 EDT
Adam D. Smith, Wenjun Ding, Yogesh K. Vohra, Cheng-Chien Chen
Recent experiments demonstrate a “robust superconductivity phenomenon” in niobium-based alloys, where the superconducting state remains intact and the critical temperature ($ T_c$ ) is largely unaffected by external pressure well above tens of gigapascal (GPa) into the megabar regime ($ \ge 100 GPa$ ). Motivated by these observations, we perform first-principles electron-phonon calculations for body-centered cubic Nb and NbTi crystals, as well as for special quasi-random structures of Nb$ _{0.5}$ Ti$ _{0.5}$ and (NbTa)$ _{0.7}$ (HfZrTi)$ _{0.3}$ high-entropy alloy (HEA). The calculations unravel the underlying mechanism of robust superconductivity, stemming from a compensation effect between varying electronic and phonon properties under pressure. The results also reveal how structural and chemical disorders modify the superconducting state. The first-principles $ T_c$ values agree quantitatively with the experiments throughout the entire pressure range under study. Our work thereby paves the way for exploring superconducting HEAs under pressure via advanced first-principles simulations.
Superconductivity (cond-mat.supr-con)
Main document: 18 pages, 3 figures; SI document: 6 pages, 4 figures
Partition function for several Ising model interface structures
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Alessio Squarcini, Piotr Nowakowski, Douglas B. Abraham, Anna Maciołek
We employ a procedure that enables us to calculate the excess free energies for a finite Ising cylinder with domain walls analytically. This procedure transparently covers all possible configurations of the domain walls under given boundary conditions and allows for a physical interpretation in terms of coarse-grained quantities such as surface and point tensions. The resulting integrals contain all the information about finite-size effects; we extract them by careful asymptotic analysis using the steepest descent method. To this end, we exactly determine the steepest descent path and analyse its features. For the general class of integrals, which are usually found in the study of systems with inclined domain walls, knowledge of the steepest descent path is necessary to detect possible intersections with poles of the integrand in the complex plane.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
27 pages, 14 figures
How universal is the mean-field universality class for percolation in complex networks?
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-23 20:00 EDT
Clustering and degree correlations are ubiquitous in real-world complex networks. Yet, understanding their role in critical phenomena remains a challenge for theoretical studies. Here, we provide the exact solution of site percolation in a model for strongly clustered random graphs, with many overlapping loops and heterogeneous degree distribution. We systematically compare the exact solution with mean-field predictions obtained from a treelike random rewiring of the network, which preserves only the degree sequence. Our results demonstrate a nontrivial interplay between degree heterogeneity, correlations and network topology, which can significantly alter both the percolation threshold and the critical exponents predicted by the mean-field. These findings highlight the need for new approaches, beyond the heterogeneous mean-field theory, to accurately describe phase transitions in complex networks with realistic topological features.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
6 pages, 2 figures + supplementary material
Tensor network calculation of boundary and corner magnetization
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-23 20:00 EDT
Roman Krcmar, Jozef Genzor, Andrej Gendiar, Tomotoshi Nishino
The Corner Transfer Matrix Renormalization Group (CTMRG) algorithm is modified to measure the magnetization at the boundary of the system, including the corners of the square-shaped lattice. Using automatic differentiation, we calculate the magnetization’s first derivative, allowing us to determine the boundary critical exponent $ \beta$ accurately.
Statistical Mechanics (cond-mat.stat-mech)