CMP Journal 2025-09-16
Statistics
Nature: 1
Nature Materials: 1
Nature Physics: 2
Nature Reviews Physics: 1
Physical Review Letters: 25
Physical Review X: 2
arXiv: 90
Nature
Delta-type glutamate receptors are ligand-gated ion channels
Original Paper | Cryoelectron microscopy | 2025-09-15 20:00 EDT
Haobo Wang, Fairine Ahmed, Jeffrey Khau, Anish Kumar Mondal, Edward C. Twomey
Delta-type ionotropic glutamate receptors (iGluRs), or GluDs, are members of the iGluR ligand-gated ion channel family, yet their function remains enigmatic1. Although GluDs are widely expressed in the brain, play key roles in synaptic organization, and harbor disease-linked mutations, whether they retain iGluR-like channel function is debated as currents have not been directly observed2,3. Here, we define GluDs as ligand-gated ion channels that are tightly regulated in cellular contexts by purifying human GluD2 (hGluD2) and directly characterizing its structure and function using cryo-electron microscopy (cryoEM) and bilayer recordings. We show that hGluD2 is activated by D-serine and γ-aminobutyric acid (GABA), with augmented activation at physiological temperatures. We reveal that hGluD2 contains an ion channel directly coupled to clamshell-like ligand-binding domains (LBDs), which are coordinated by the amino terminal domain (ATD) above the ion channel. Ligand binding triggers channel opening via an asymmetric mechanism, and a cerebellar ataxia point mutation in the LBD rearranges the receptor architecture and induces leak currents. Our findings demonstrate that GluDs possess the intrinsic biophysical properties of ligand-gated ion channels, reconciling prior conflicting observations to establish a framework for understanding their cellular regulation and for developing therapies targeting GluD2.
Cryoelectron microscopy, Ion channels in the nervous system, Ligand-gated ion channels
Nature Materials
Molecular afterglow imaging for biomedical applications
Review Paper | Fluorescent probes | 2025-09-15 20:00 EDT
Cheng Xu, Yan Zhang, Gaolin Liang, Kanyi Pu
Afterglow imaging is an emerging optical modality using agents that emit long-lasting luminescence after excitation ceases to eliminate tissue autofluorescence and improve signal-to-background ratios, achieving high imaging sensitivity and deep tissue penetration. Here we review recent advances in molecular afterglow imaging for biomedical applications, highlighting the materials and mechanisms involved in afterglow imaging modalities induced by light, ultrasound and ionizing radiation, termed photoafterglow, sonoafterglow and radioafterglow, respectively. We describe strategies to modulate the lifetime, intensity and wavelength of afterglow materials and principles for designing afterglow imaging probes that feature biomarker-activatable signal readouts and optimal biophysical properties for in vivo applications. We also highlight the applications of afterglow materials in disease diagnosis, imaging-guided therapy and in vitro diagnostics, and discuss the current challenges in the clinical translation of these technologies.
Fluorescent probes, Imaging techniques
Nature Physics
Constant-overhead magic state distillation
Original Paper | Computational science | 2025-09-15 20:00 EDT
Adam Wills, Min-Hsiu Hsieh, Hayata Yamasaki
Most schemes for realistic quantum computing require access to so-called magic states to allow universal quantum computing. Because the preparation process may be noisy, magic state distillation methods are needed to improve their accuracy and suppress any potential errors. Unfortunately, magic state distillation is resource-intensive and often considered a bottleneck to scalable quantum computation. Here, the cost is defined by the overhead: the ratio of noisy input magic states to cleaner outputs. This is known to scale as ({\mathcal{O}}({\log }^{\gamma }(1/\epsilon ))) as \epsilon → 0, where \epsilon is the output error rate and γ is some constant. Reducing this overhead, corresponding to smaller γ, is highly desirable to remove the bottleneck. However, identifying the smallest achievable exponent γ for distilling magic states of qubits has proved challenging. Here, we resolve this problem by demonstrating protocols with the optimal exponent γ = 0, thus corresponding to magic state distillation with a constant overhead, and we show that this is achievable for the most important magic states such as (\left\vert {\mathsf{T}}\right\rangle) and (\left\vert {\mathsf{CCZ}}\right\rangle). This is achieved by using algebraic geometry constructions to build the first asymptotically good quantum codes with transversal non-Clifford gates, for which we also construct an efficient decoder with linear decoding radius.
Computational science, Information theory and computation, Quantum information
Observation of the Yamaji effect in a cuprate superconductor
Original Paper | Electronic properties and materials | 2025-09-15 20:00 EDT
Mun K. Chan, Katherine A. Schreiber, Oscar E. Ayala-Valenzuela, Eric D. Bauer, Arkady Shekhter, Neil Harrison
The pseudogap state of high-temperature superconducting cuprates, known for its partial gapping of the Fermi surface above the superconducting transition temperature, is believed to hold the key to understanding the origin of Planckian relaxation and quantum criticality. However, the nature of the Fermi surface in the pseudogap state has remained a fundamental open question. Here we report the observation of the Yamaji effect, which appears as a peak in the c-axis resistivity at a specific angle of the applied magnetic field, in angle-dependent magnetoresistivity measurements above the critical temperature in the cuprate HgBa2CuO4+δ. The observation of the Yamaji peak is evidence for small Fermi-surface pockets in the normal state of the pseudogap phase. The small size of the pockets, each estimated to occupy only 1.3% of the Brillouin zone area, is not expected given the absence of long-range broken translational symmetry.
Electronic properties and materials, Superconducting properties and materials
Nature Reviews Physics
Artificial gauge fields in photonics
Review Paper | Photonic crystals | 2025-09-15 20:00 EDT
Wange Song, Yi Yang, Zhiyuan Lin, Xuanyu Liu, Shengjie Wu, Chen Chen, Yongguan Ke, Chaohong Lee, Wei Liu, Shining Zhu, Yuri Kivshar, Tao Li, Shuang Zhang
Structured photonic systems, from photonic crystals to metamaterials and metasurfaces, provide a broad platform for photonic gauge fields. This artificial version of the real gauge fields in electrodynamics can induce a range of exotic functionalities in many branches of optical physics, enabling the manipulation of light and its interactions with various photonic structures in new and interesting ways. In this Review, we provide a viewpoint on how the concept of artificial gauge fields can connect seemingly unrelated optical effects. Artificial gauge fields in photonics can be either vectorial or scalar, Abelian or non-Abelian, real or complex. They apply not only to conventional real and momentum spaces, but also to spaces spanned by other synthetic dimensions, and are applicable to both semiclassical and quantum systems. In this Review, leveraging the wide applicability of the artificial gauge field, we connect different optical branches, including topological photonics, non-Abelian physics and non-Hermitian photonics. We discuss the current progress and next steps of research on optical gauge fields as well as their potential for future applications.
Photonic crystals, Topological defects, Transformation optics
Physical Review Letters
Illuminating Black Hole Shadows with Dark Matter Annihilation
Article | Cosmology, Astrophysics, and Gravitation | 2025-09-16 06:00 EDT
Yifan Chen, Ran Ding, Yuxin Liu, Yosuke Mizuno, Jing Shu, Haiyue Yu, and Yanjie Zeng
The morphology of black hole shadows observed by the Event Horizon Telescope places new constraints on dark matter annihilation.
Phys. Rev. Lett. 135, 121001 (2025)
Cosmology, Astrophysics, and Gravitation
TeV Solar Gamma Rays as a Probe for the Solar Internetwork Magnetic Fields
Article | Plasma and Solar Physics, Accelerators and Beams | 2025-09-16 06:00 EDT
Kenny C. Y. Ng, Andrew Hillier, and Shin’ichiro Ando
Recently, solar gamma rays produced by cosmic rays interacting with the solar atmosphere have been detected in the GeV to TeV energy range, revealing that cosmic rays are significantly affected by magnetic fields in the solar atmosphere. However, much of the observations remain unexplained by existi…
Phys. Rev. Lett. 135, 125201 (2025)
Plasma and Solar Physics, Accelerators and Beams
Quantum Monte Carlo Pair Orbital Wave Functions for Periodic Systems
Article | Condensed Matter and Materials | 2025-09-16 06:00 EDT
Lubos Mitas
We derive many-body single and multireference wave functions for quantum Monte Carlo of periodic systems with an antisymmetric portion that explicitly integrates over the Brillouin zone of one-particle Bloch states. The wave functions are BCS-like determinants for singlets and Pfaffians for polarize…
Phys. Rev. Lett. 135, 126401 (2025)
Condensed Matter and Materials
Topological Valley Transport in Bilayer Graphene Induced by Interlayer Sliding
Article | Condensed Matter and Materials | 2025-09-16 06:00 EDT
Jie Pan, Huanhuan Wang, Lin Zou, Xiaoyu Wang, Lihao Zhang, Xueyan Dong, Haibo Xie, Yi Ding, Yuze Zhang, Takashi Taniguchi, Kenji Watanabe, Shuxi Wang, and Zhe Wang
Sliding one layer of bilayer graphene over the other provides a powerful way to tune the material's electronic properties.
Phys. Rev. Lett. 135, 126603 (2025)
Condensed Matter and Materials
Genuine Topological Anderson Insulator from Impurity Induced Chirality Reversal
Article | Condensed Matter and Materials | 2025-09-16 06:00 EDT
Avedis Neehus, Frank Pollmann, and Johannes Knolle
We investigate a model of Dirac fermions with mass impurities that open a global topological gap even in the dilute limit. Surprisingly, we find that the chirality of this mass term, i.e., the sign of the Chern number, can be reversed by tuning the magnitude of the single-impurity scattering. Conseq…
Phys. Rev. Lett. 135, 126604 (2025)
Condensed Matter and Materials
Vertical Soliton-Assisted Current Switching in Extremely Thick FeGd Ferrimagnets
Article | Condensed Matter and Materials | 2025-09-16 06:00 EDT
Teng Xu, Zhengde Xu, Yiqing Dong, Yang Cheng, Ledong Wang, Hongmei Feng, Hao Bai, Kun Xu, Xinyu Shu, Pu Yu, Heng-An Zhou, Enlong Liu, Shikun He, Chuanying Xi, Guoqiang Yu, Xuepeng Qiu, Se Kwon Kim, Jing Zhu, Zhifeng Zhu, and Wanjun Jiang
Current-induced spin-orbit torques (SOTs) can electrically switch magnetic films. The thickness of these films is usually limited to a few tenths of nanometers. Toward stable spintronic nanodevices, it is important to explore the upper thickness limit and to identify the associated SOT switching mec…
Phys. Rev. Lett. 135, 126703 (2025)
Condensed Matter and Materials
Limitations of Gaussian Measurements in Quantum Imaging
Article | Quantum Information, Science, and Technology | 2025-09-15 06:00 EDT
Yunkai Wang and Sisi Zhou
Imaging thermal sources naturally yields Gaussian states at the receiver, raising the question of whether Gaussian measurements can perform optimally in quantum imaging. In this Letter, we establish no-go theorems on the performance of Gaussian measurements for imaging thermal sources in the limit o…
Phys. Rev. Lett. 135, 120201 (2025)
Quantum Information, Science, and Technology
Geometric Phase Transition of the Three-Dimensional ${\mathbb{Z}}_{2}$ Lattice Gauge Model
Article | Quantum Information, Science, and Technology | 2025-09-15 06:00 EDT
Ramgopal Agrawal, Leticia F. Cugliandolo, Lara Faoro, Lev B. Ioffe, and Marco Picco
After fifty years of lattice gauge theories (LGTs), the nature of the transition between their topological phases (confinement or deconfinement) remains challenging due to the absence of a local order parameter. In this work, we conduct a percolation analysis of Wegner's three-dimensional lattice…
Phys. Rev. Lett. 135, 120601 (2025)
Quantum Information, Science, and Technology
Universality Class of the First Levels in Low-Dimensional Gravity
Article | Particles and Fields | 2025-09-15 06:00 EDT
Alexander Altland, Jeremy van der Heijden, Tobias Micklitz, Moshe Rozali, and Joaquim Telles de Miranda
We investigate the physics of a small group of quantum states defined above the sharply defined ground state of a chaotic ensemble. This "universality class of the first levels" is realized in the majority of "synthetic" random matrix models but, for all we know, in only one microscopically defined …
Phys. Rev. Lett. 135, 121601 (2025)
Particles and Fields
Measurement of Reactor Antineutrino Oscillation at $\mathrm{SNO}+$
Article | Particles and Fields | 2025-09-15 06:00 EDT
M. Abreu et al. ()
Collaboration reports its second spectral analysis of reactor antineutrino oscillation using 286 ton-yr of new data. The measured energies of reactor antineutrino candidates were fitted to obtain the second-most precise determination of the neutrino mass-squared difference
Phys. Rev. Lett. 135, 121801 (2025)
Particles and Fields
Search for Millicharged Particles in Proton-Proton Collisions at $\sqrt{s}=13.6\text{ }\text{ }\mathrm{TeV}$
Article | Particles and Fields | 2025-09-15 06:00 EDT
S. Alcott et al.
We report on a search for elementary particles with charges much smaller than the electron charge using a data sample of proton-proton collisions provided by the CERN Large Hadron Collider in 2023-24, corresponding to an integrated luminosity of at a center-of-mass energy of 13.6 TeV. Th…
Phys. Rev. Lett. 135, 121802 (2025)
Particles and Fields
Inclusive Semileptonic Decays of the ${D}_{s}$ Meson: Lattice QCD Confronts Experiments
Article | Particles and Fields | 2025-09-15 06:00 EDT
Alessandro De Santis, Antonio Evangelista, Roberto Frezzotti, Giuseppe Gagliardi, Paolo Gambino, Marco Garofalo, Christiane Franziska Groß, Bartosz Kostrzewa, Vittorio Lubicz, Francesca Margari, Marco Panero, Francesco Sanfilippo, Silvano Simula, Antonio Smecca, Nazario Tantalo, and Carsten Urbach
Standard model prediction for the semileptonic decay of meson using state-of-the-art lattice QCD calculation agrees well with the experimental determinations.
Phys. Rev. Lett. 135, 121901 (2025)
Particles and Fields
Host-Dependent Frequency Offsets in $^{229}\mathrm{Th}$ Nuclear Clockwork
Article | Atomic, Molecular, and Optical Physics | 2025-09-15 06:00 EDT
U. C. Perera, H. W. T. Morgan, Eric R. Hudson, and Andrei Derevianko
Host-dependent variations of Thorium-229 nuclear clock frequencies in solid-state hosts are predicted using a combination of advanced methods.
Phys. Rev. Lett. 135, 123001 (2025)
Atomic, Molecular, and Optical Physics
Phase Transitions in Nonreciprocal Driven-Dissipative Condensates
Article | Atomic, Molecular, and Optical Physics | 2025-09-15 06:00 EDT
Ron Belyansky, Cheyne Weis, Ryo Hanai, Peter B. Littlewood, and Aashish A. Clerk
We investigate the influence of boundaries and spatial nonreciprocity on nonequilibrium driven-dissipative phase transitions. We focus on a one-dimensional lattice of nonlinear bosons described by a Lindblad master equation, where the interplay between coherent and incoherent dynamics generates nonr…
Phys. Rev. Lett. 135, 123401 (2025)
Atomic, Molecular, and Optical Physics
Correlated Quasiparticle Poisoning from Phonon-Only Events in Superconducting Qubits
Article | Atomic, Molecular, and Optical Physics | 2025-09-15 06:00 EDT
E. Yelton, C. P. Larson, K. Dodge, K. Okubo, and B. L. T. Plourde
Errors that are correlated across a qubit array pose an obstacle to quantum error correction. We observe elevated correlated poisoning rates in superconducting qubit arrays at the start of a cooldown followed by power-law reductions in time, while the rate of offset charge shifts remains constant, e…
Phys. Rev. Lett. 135, 123601 (2025)
Atomic, Molecular, and Optical Physics
Influence of Collisional Effects on Ion-Acoustic Wave Properties in Non-Maxwellian Laser-Driven Plasmas
Article | Plasma and Solar Physics, Accelerators and Beams | 2025-09-15 06:00 EDT
R. Capdessus, C. Ruyer, A. Debayle, P. Loiseau, and P. E. Masson-Laborde
Collisional effects significantly influence inertial confinement fusion hohlraum plasmas, where non-Maxwellian inverse bremsstrahlung heating and collision-induced anisotropy alter the kinetic plasma response. We derived the linear ion-acoustic wave (IAW) dispersion relation, revealing the necessity…
Phys. Rev. Lett. 135, 125101 (2025)
Plasma and Solar Physics, Accelerators and Beams
Eliminating Defect States in Monolayer Tungsten Diselenide by Coupling with a c-Plane Sapphire Surface
Article | Condensed Matter and Materials | 2025-09-15 06:00 EDT
Chen Huang, Jinhuan Wang, Yilin Chen, Zuo Feng, Yuexing Xia, Guangjie Yao, Mengze Zhao, Guodong Xue, Si Zhou, Xiaozhi Xu, Xinfeng Liu, Enge Wang, Ji Chen, Kaihui Liu, and Hao Hong
Selenium vacancies are repaired by oxygen atoms transferred from the highly active c-plane in sapphire showing that defect states can be eliminated below the optical spectrum-detectable level.
Phys. Rev. Lett. 135, 126201 (2025)
Condensed Matter and Materials
Entropy Spectroscopy of a Bilayer Graphene Quantum Dot
Article | Condensed Matter and Materials | 2025-09-15 06:00 EDT
C. Adam, H. Duprez, N. Lehmann, A. Yglesias, A. O. Denisov, S. Cances, M. J. Ruckriegel, M. Masseroni, C. Tong, W. Huang, D. Kealhofer, R. Garreis, K. Watanabe, T. Taniguchi, K. Ensslin, and T. Ihn
We measure the entropy change of charge transitions in an electrostatically defined quantum dot in bilayer graphene. Entropy provides insights into the equilibrium thermodynamic properties of both ground and excited states beyond transport measurements. For the one-carrier regime, the obtained entro…
Phys. Rev. Lett. 135, 126202 (2025)
Condensed Matter and Materials
Disorder-Induced Suppression of Superconductivity in Infinite-Layer Nickelates
Article | Condensed Matter and Materials | 2025-09-15 06:00 EDT
Abhishek Ranna, Romain Grasset, Martin Gonzalez, Kyuho Lee, Bai Yang Wang, Edgar Abarca Morales, Florian Theuss, Zuzanna H. Filipiak, Michal Moravec, Marcin Konczykowski, Harold Y. Hwang, Andrew P. Mackenzie, and Berit H. Goodge
The pairing symmetry of superconducting infinite-layer nickelates is a fundamental yet experimentally challenging question. We employ high-energy electron irradiation to induce disorder in superconducting thin films, examine the impact of pair-breaking defects on superconductivity…
Phys. Rev. Lett. 135, 126501 (2025)
Condensed Matter and Materials
Three-Dimensional Topological Valley Photonics
Article | Condensed Matter and Materials | 2025-09-15 06:00 EDT
Wenhao Li, Qiaolu Chen, Ning Han, Xinrui Li, Fujia Chen, Junyao Wu, Yuang Pan, Yudong Ren, Hongsheng Chen, Haoran Xue, and Yihao Yang
Topological valley photonics, which exploits valley degrees of freedom to manipulate electromagnetic waves, offers a practical and effective pathway for various classical and quantum photonic applications across the entire spectrum. Current valley photonics, however, has been limited to two dimensio…
Phys. Rev. Lett. 135, 126601 (2025)
Condensed Matter and Materials
Dimensional Hierarchy of Topological Bound States in the Continuum
Article | Condensed Matter and Materials | 2025-09-15 06:00 EDT
Shunda Yin, Zhenyu Wang, Liping Ye, Hailong He, Manzhu Ke, Weiyin Deng, Jiuyang Lu, and Zhengyou Liu
Bound states in the continuum (BICs), with the ability of trapping and manipulating waves within the radiation continuum, have gained significant attention for their potential applications in optics and acoustics. However, challenges arise in reducing wave leakage and noise from fabrication imperfec…
Phys. Rev. Lett. 135, 126602 (2025)
Condensed Matter and Materials
Spin Demons in $d$-Wave Altermagnets
Article | Condensed Matter and Materials | 2025-09-15 06:00 EDT
Pieter M. Gunnink, Jairo Sinova, and Alexander Mook
Demons are a type of plasmons, which consist of out-of-phase oscillations of electrons in different bands. Here, we show that -wave altermagnets, a recently discovered class of collinear magnetism, naturally realize a spin demon, which consists of out-of-phase movement of the two spin species. The …
Phys. Rev. Lett. 135, 126701 (2025)
Condensed Matter and Materials
Strong Coupling of Chiral Magnons in Altermagnets
Article | Condensed Matter and Materials | 2025-09-15 06:00 EDT
Zhejunyu Jin, Tianci Gong, Jie Liu, Huanhuan Yang, Zhaozhuo Zeng, Yunshan Cao, and Peng Yan
Altermagnets have recently been identified as a new class of magnets that break time-reversal symmetry without exhibiting net magnetization. The role of the dipole-dipole interaction (DDI) on their dynamical properties, however, is yet to be addressed. In this work, we show that the DDI can induce t…
Phys. Rev. Lett. 135, 126702 (2025)
Condensed Matter and Materials
Universal Scale-Free Decay of Tracer-Bath Correlations in $d$-Dimensional Interacting Particle Systems
Article | Statistical Physics; Classical, Nonlinear, and Complex Systems | 2025-09-15 06:00 EDT
Davide Venturelli, Pierre Illien, Aurélien Grabsch, and Olivier Bénichou
Quantifying the correlations between the position of a tagged tracer and the density of surrounding bath particles is crucial for understanding tracer diffusion in interacting particle systems, and for characterizing the response properties of the bath. We address this problem analytically for both …
Phys. Rev. Lett. 135, 127101 (2025)
Statistical Physics; Classical, Nonlinear, and Complex Systems
Activation Volume Facilitating Chemical Reaction under Mechanical Stress
Article | Polymers, Chemical Physics, Soft Matter, and Biological Physics | 2025-09-15 06:00 EDT
Yilong Jiang, Junyu Bin, Junhui Sun, Seong H. Kim, Linmao Qian, Lei Chen, and Yang Wang
First-principles calculations confirm the validity a new model of activation volume based on inherent stress difference and effective volume change, making possible to devise engineering strategies to regulate mechanochemical effects in chemical reactions.
Phys. Rev. Lett. 135, 128001 (2025)
Polymers, Chemical Physics, Soft Matter, and Biological Physics
Physical Review X
Learning Geometric Models for Developmental Dynamics
Article | | 2025-09-15 06:00 EDT
Addison Howe and Madhav Mani
A neural network model that learns a "developmental landscape" linked to underlying genes provides a framework for understanding tissue formation and differentiation.
Phys. Rev. X 15, 031070 (2025)
Anticoncentration in Clifford Circuits and Beyond: From Random Tensor Networks to Pseudomagic States
Article | | 2025-09-15 06:00 EDT
Beatrice Magni, Alexios Christopoulos, Andrea De Luca, and Xhek Turkeshi
An analysis of how evenly quantum states spread out in Clifford circuits and tensor networks provides new insights for quantum sampling, benchmarking, and computational quantum advantage.
Phys. Rev. X 15, 031071 (2025)
arXiv
Crystal Systems Classification of Phosphate-Based Cathode Materials Using Machine Learning for Lithium-Ion Battery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Yogesh Yadav, Sandeep K Yadav, Vivek Vijay, Ambesh Dixit
The physical and chemical characteristics of cathodes used in batteries are derived from the lithium-ion phosphate cathodes crystalline arrangement, which is pivotal to the overall battery performance. Therefore, the correct prediction of the crystal system is essential to estimate the properties of cathodes. This study applies machine learning classification algorithms for predicting the crystal systems, namely monoclinic, orthorhombic, and triclinic, related to Li P (Mn, Fe, Co, Ni, V) O based Phosphate cathodes. The data used in this work is extracted from the Materials Project. Feature evaluation showed that cathode properties depend on the crystal structure, and optimized classification strategies lead to better predictability. Ensemble machine learning algorithms such as Random Forest, Extremely Randomized Trees, and Gradient Boosting Machines have demonstrated the best predictive capabilities for crystal systems in the Monte Carlo cross-validation test. Additionally, sequential forward selection (SFS) is performed to identify the most critical features influencing the prediction accuracy for different machine learning models, with Volume, Band gap, and Sites as input features ensemble machine learning algorithms such as Random Forest (80.69%), Extremely Randomized Tree (78.96%), and Gradient Boosting Machine (80.40%) approaches lead to the maximum accuracy towards crystallographic classification with stability and the predicted materials can be the potential cathode materials for lithium ion batteries.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
21 Pages, 12 Figures, Submitted to Physica B: Condensed Matter Journal
Nanosculpting lateral weak link junctions in superconducting Fe(Te,Se)/Bi2Te3 with focused Si++ ions and implications on vortex pinning
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-16 20:00 EDT
Debarghya Mallick, Sujoy Ghosh, An Hsi Chen, Qiangsheng Lu, Liam Collins, Sangsoo Kim, Gyula Eres, Ivan Kravchenko, Stephen Jesse, Steven J. Randolph, Scott T. Retterer, Matthew Brahlek, Robert G. Moore
Superconductor-normal-superconductor (SC-N-SC) weak links enable Cooper-pair tunneling and serve as Josephson junctions (JJs) used in modern superconducting qubits. Conventional JJs rely on vertically stacked Al-AlOx-Al trilayers that are difficult to fabricate and are sensitive to ambient exposure. Here, we demonstrate an all-in-plane alternative by “nanosculpting” ~100 nm-wide channels into thin films of FeTe0.75Se0.25/Bi2Te3 (FTS/BT), a candidate topological superconductor, with a Si++ focusses ion beam (FIB). Systematic irradiation shows that increasing the ion dose, while keeping the beam energy constant, progressively suppresses both the critical temperature (Tc) and critical current (Ic), confirming the creation of a controllable weak link even though a Fraunhofer interference pattern is not observed. Kelvin prove force microscopy , atomic force microscopy and scanning electron microscopy corroborate the structural and electronic modification of the irradiated region. Ic (B) measurements reveal a slower field-induced decay of Ic at higher doses, indicating that irradiation-induced defects act as vortex-pinning centers that mitigate vortex motion and associated dissipation, By tuning beam energy and dose, the process shifts from SC-N-SC regime toward a superconductor-insulator-superconductor (SC-I-SC) geometry, offering a simple scalable pathway to JJ fabrication. These results established FIB pattering as a versatile platform for engineering robust, scalable fault-tolerant qubits.
Superconductivity (cond-mat.supr-con)
Finite-Size Spectral Signatures of Order by Quantum Disorder: A Perspective from Anderson’s Tower of States
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Subhankar Khatua, Griffin C. Howson, Michel J. P. Gingras, Jeffrey G. Rau
In frustrated magnetic systems with a subextensive number of classical ground states, quantum zero-point fluctuations can select a unique long-range ordered state, a celebrated phenomenon referred to as \emph{order by quantum disorder} (ObQD). For frustrated spin-$ \frac{1}{2}$ systems, unbiased numerical methods able to expose ObQD are necessary. We show that ObQD can be identified from exact diagonalization (ED) calculations through an analysis akin to the Anderson tower of states associated with spontaneous symmetry breaking. By defining an effective quantum rotor model, we describe the competition between ObQD-induced localization of the rotor and its tunneling between symmetry-related ground states, identifying the crossover lengthscale from the finite-size regime where the rotor is delocalized, to the infinite system-size limit where it becomes localized. This rotor model relates the characteristic splittings in the ED energy spectrum to the ObQD selection energy scale, providing an estimate that can be compared to spin wave calculations. We demonstrate the general applicability of this approach in one-, two- and three-dimensional frustrated spin models that exhibit ObQD.
Strongly Correlated Electrons (cond-mat.str-el)
Main text (7 pages including 4 figures), 1 page End Matter including 2 figures, and supplemental material (6 pages including 3 figures )
Terahertz electrodynamics in a zero-field Wigner crystal
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Su-Di Chen, Ruishi Qi, Ha-Leem Kim, Qixin Feng, Ruichen Xia, Dishan Abeysinghe, Jingxu Xie, Takashi Taniguchi, Kenji Watanabe, Dung-Hai Lee, Feng Wang
In clean two-dimensional (2D) systems, electrons are expected to self-organize into a regular lattice, a Wigner crystal, when their mutual Coulomb repulsion overwhelms kinetic energy. Understanding the Wigner crystal at zero magnetic field is a long-sought goal in physics, thanks to its fundamental simplicity and possible connection to the density-driven metal-insulator transition. To date, evidence for such a crystal has been reported across various platforms. However, the AC conductivity of a zero-field Wigner crystal, a key observable characterizing its electrodynamics, has never been measured. Here, we develop an ultrasensitive on-chip terahertz (THz) spectroscopy technique to probe the AC conductivity in electrostatically gated monolayer MoSe2 encapsulated in hexagonal boron nitride. We observe a sub-THz resonance corresponding to the pinning mode of a zero-field Wigner crystal, whose frequency is orders of magnitude higher than those under high magnetic fields. Using the pinning mode as an indicator, we reveal that moderate disorder notably stabilizes the Wigner crystal. With increasing density towards melting, we find that the pinning mode of the Wigner crystal coexists with a growing Drude component characteristic of an electron liquid, and the competition between these two components in the conductivity spectra leads to the insulator-metal transition of the 2D electron system. Our findings not only elucidate the low-energy electrodynamics of a zero-field Wigner crystal, but also establish on-chip THz spectroscopy as a powerful probe for correlated quantum phases in two-dimensional materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Observation of Anomalous Thermal Hall Effect in a Kagome Superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-16 20:00 EDT
Hiroki Yoshida, Hikaru Takeda, Jian Yan, Yui Kanemori, Brenden R. Ortiz, Yuzki M. Oey, Stephen D. Wilson, Marcin Konczykowski, Kota Ishihara, Takasada Shibauchi, Minoru Yamashita
Broken time-reversal symmetry (TRS) in superconductors can induce not only spontaneous magnetization by the finite angular momentum of Cooper pairs, but also anomalous thermal Hall effects (ATHEs), whose detection has been extremely challenging. Here we report the successful observation of an ATHE developing below the superconducting transition temperature at zero magnetic field in the kagome-lattice superconductor CsV3Sb5. This finding is verified by the absence of a signal in a conventional type-II superconductor using the same setup and by ruling out the trapped-vortex effects through micro-Hall array measurements. Remarkably, both the temperature dependence and the magnitude of the observed anomalous thermal Hall conductivity are quite different from those expected for the quantized thermal edge current of an intrinsic ATHE, but consistent with extrinsic impurity-induced ATHEs in chiral superconductivity. Our study of ATHE offers an alternative approach to probe TRS breaking in the superconducting states.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 5 figures, and Supplementary Materials, to appear in Science Advances
Inverse design of drying-induced assembly of multicomponent colloidal-particle films using surrogate models
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
Mayukh Kundu, Michaela Bush, Chris A. Kieslich, Michael P. Howard
The properties of films assembled by drying colloidal-particle suspensions depend sensitively on both the particles and the processing conditions, making them challenging to engineer. In this work, we develop and test an inverse-design strategy based on surrogate modeling to identify conditions that yield a target film structure. We consider a two-component hard-sphere colloidal suspension whose designable parameters are the particle sizes, the initial composition of particles, and the drying rate. Film drying is simulated approximately using Brownian dynamics. Surrogate models based on Gaussian process regression (GPR) and Chebyshev polynomial interpolation are trained on a loss function, computed from the simulated film structures, that guides the design process. We find the surrogate models to be effective for both approximation and optimization using only a small number of samples of the loss function. The GPR models are typically slightly more accurate than polynomial interpolants trained using comparable amounts of data, but the polynomial interpolants are more computationally convenient. This work has important implications not only for designing colloidal materials but also more broadly as a strategy for engineering nonequilibrium assembly processes.
Soft Condensed Matter (cond-mat.soft)
A new skyrmion topological transition driven by higher-order exchange interactions in Janus MnSeTe
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Megha Arya, Moritz A. Goerzen, Lionel Calmels, Rémi Arras, Soumyajyoti Haldar, Stefan Heinze, Dongzhe Li
Two-dimensional (2D) van der Waals magnets offer a promising platform for pushing skyrmion technology to the single-layer limit with high tunability. While Dzyaloshinskii-Moriya interaction (DMI) is often recognized as central to skyrmion formation, their stability, collapse, and topological transition in 2D materials remain largely unexplored. In particular, the effect of higher-order exchange interactions (HOI) on these phenomena is unknown. Here, using first-principles calculations and atomistic spin simulations, we report a new topological transition generated by HOI, which we term ‘ferric transition’, in single-layer MnSeTe. Surprisingly, skyrmion stability and collapse remain largely unaffected by HOI due to the dominant role of DMI near the saddle point, whereas the Bloch point is strongly modified, giving rise to this novel transition. This mechanism is fundamentally distinct from the well-known radial and chimera transitions. Moreover, we predict that Janus MnSeTe exhibits remarkably high skyrmion energy barriers due to its strong DMI, among the highest reported for intrinsic 2D magnets. Our findings unveil an unexpected role of HOI in skyrmion topological transitions and establish Janus MnSeTe as a robust platform for 2D skyrmionics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 Figures
Localization and Wetting of 4He Inside Pre-plated Nanopores
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Sutirtha Paul, Taras Lakoba, Paul E. Sokol, Adrian Del Maestro
Low dimensional quantum fluids, where one can probe the effects of enhanced thermal and quantum fluctuations on macroscopic quantum wavefunctions, can be experimentally realized through transverse physical confinement of superfluid helium on scales smaller than the coherence length. Reaching this scale is difficult, requiring confinement in single or multiple pores with nanometer radii. Porous silicates such as MCM-41 have a pore radius larger than the coherence length of 4He, and in this work we systematically explore the possibility of pre-plating pores with different elements to reduce the pore size without localizing the confined superfluid. Through a direct solution of the few-body Schrodinger equation combined with quantum Monte Carlo simulations, we explore the behavior of helium confined inside cylindrical nanopores for a range of pre-plating elements, including rare gases and alkali metals. For rare gases, we find that helium remains strongly attracted to the pore walls and any atoms in the core form an incompressible liquid. For alkali metals such as Cs, weak interactions between helium and the pre-plating material prevent localization near the walls and enable delocalization in the pore center. Our results extend previous results for helium wetting on flat two dimensional coated substrates to the curved geometry inside nanopores, and demonstrate that alkali pre-plated nanopores may enable a tunable one-dimensional confined quantum liquid of helium.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 10 figures. For associated data and code repository see: this https URL
Metastable phase separation and information retrieval in multicomponent mixtures
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Rodrigo Braz Teixeira, Izaak Neri, Pablo Sartori
Liquid mixtures can separate into phases with distinct composition. This phenomenon has recently come back to prominence due to its role in complex biological liquids, such as the cytoplasm, which contain thousands of components. For simple two-component mixtures phase-separated states are global free energy minima. However, local free energy minima, i.e. metastable states, are known to play a dominant role in complex systems with many components. For example, Hopfield neural networks can retrieve information from partial cues via relaxation to metastable states. Under what conditions can phase separated states be metastable, and what are the implications for information processing in multicomponent liquids? In this work we develop the general thermodynamic formalism of metastable phase separation. We then apply this formalism to an illustrative toy example inspired by recent experiments, binary mixtures with high-order interactions. Finally, as core application of the formalism, we study metastability in Hopfield liquids, a class of multicomponent mixtures capable of storing information on the composition of phases. We show that these phases can be retrieved from partial cues via metastable phase separation. Spatial simulations of liquids with a large number of components match our analytical solution. Our work suggests that complex biological mixtures can perform information retrieval through metastable phase separation.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
26 pages, 8 figures, 16 pages of supplement
Programmable Beam Control for Electron Energy-Loss Spectroscopy and Ptychography
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Mariana Palos, Liam Spillane, Geri Topore, Yaqi Li, David Pesquera, Colin Ophus, Stephanie M. Ribet, Michele Shelly Conroy
Programmable electron-beam scanning offers new opportunities to improve dose efficiency and suppress scan-induced artifacts in scanning transmission electron microscopy. Here, we systematically benchmark the impact of non-raster trajectories, including spiral and multi-pass sequential patterns, on two dose sensitive techniques: electron energy-loss spectroscopy (EELS) and ptychography. Using DyScO3 as a model perovskite, we compare spatial resolution, spectral fidelity, and artifact suppression across scan modes. Ptychographic phase reconstructions consistently achieve atomic resolution and remain robust to large jumps in probe position. In contrast, atomic-resolution EELS maps show pronounced sensitivity to probe motion, with sequential and spiral scans introducing non-uniform elemental contrast. Finally, spiral scanning applied under cryogenic conditions in BaTiO3 thin films improves dose uniformity and mitigates drift related distortions. These results establish practical guidelines for the implementation of programmable scan strategies in low-dose 4D-STEM and highlight the inherent resilience of ptychography to trajectory-induced artifacts.
Materials Science (cond-mat.mtrl-sci)
11 pages long, 5 figures in main text and 4 in supporting infomration
Design and Optimization of Spin Dynamics in Ge Quantum Dots: g-Factor Modulation, Dephasing Sweet Spots, and Phonon-Induced Relaxation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Accurate modeling of spin dynamics in hole-based quantum dot qubits demands high-fidelity simulations that capture realistic device geometries, material interfaces, and self-consistent electrostatics. Here, we present a comprehensive three-dimensional study of gate-defined quantum dot hole spin qubits in strained Si$ _{0.2}$ Ge$ _{0.8}$ /Ge heterostructures. In contrast to prior work relying on idealized confinement or decoupled Poisson-Schrödinger treatments, our approach combines self-consistent electrostatics with a four-band Luttinger-Kohn Hamiltonian to resolve spin-orbit interactions, wavefunction asymmetries, and g-tensor anisotropies in realistic device structures. We quantify the impact of device size and gate bias on wavefunction localization, electric-field-induced g-factor modulation, and identify “sweet spots” in vertical electric field where g-factor sensitivity to charge noise is minimized, enhancing spin dephasing times. Spin relaxation due to phonon coupling is also modeled, revealing size-dependent T1 behavior consistent with strong Rashba-type spin-orbit coupling and a magnetic-field scaling near $ B^{-8}$ . This work establishes a predictive modeling framework for optimizing spin coherence in planar Ge quantum dots and provides quantitative design guidance for scalable, electrically controlled hole spin qubits in group-IV semiconductors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Direct Observation of the Lindhard Continuum using Resonant Inelastic X-ray Scattering
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Eder G. Lomeli, Sarbajaya Kundu, Yi-De Chuang, Zengqing Zhuo, Ke Chen, Xiaoxing Xi, Lingjia Shen, Georgi L. Dakovski, Stephan Geprägs, Brian Moritz, Thomas P. Devereaux, John Vinson, Matthias F. Kling, Edwin W. Huang, Daniel Jost
Understanding the excitations of quantum materials is essential for unraveling how their microscopic constituents interact. Among these, particle-hole excitations form a particularly important class, as they govern fundamental processes such as screening, dissipation, and transport. In metals, the continuum of electron-hole excitations is described by the Lindhard function. Although central to the theory of Fermi liquids, the corresponding Lindhard continuum has remained experimentally elusive. Here, we report its direct observation in the weakly correlated metal MgB$ _{2}$ using ultra-soft resonant inelastic X-ray scattering (RIXS). We resolve a linearly dispersing excitation with velocity comparable to the Fermi velocity and find quantitative agreement with simulations of the non-interacting charge susceptibility. A detailed analysis and decomposition of the simulations reveal the intra-band origin of this low-energy excitation, confirming it as the Lindhard continuum. Our results establish ultra-soft RIXS as a momentum-resolved probe of the fermiology in metals and call for deeper investigations of continuum features in RIXS and related spectroscopy of other materials beyond MgB$ _{2}$ .
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
A Snapshot of Time-Dependent Density-Functional Theory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Time-dependent density-functional theory (TDDFT) is an extension of ground-state density-functional theory which allows the treatment of electronic excited states and a wide range of time-dependent phenomena in the linear and nonlinear regime, including coupled electron-nuclear dynamics. TDDFT is a vibrant field with many exciting applications in physics, (bio)chemistry, materials science and other areas. This perspective gives an overview of recent developments and successes, formal and computational challenges, and hot topics in TDDFT.
Materials Science (cond-mat.mtrl-sci)
28 pages, 13 figures
Achieving fully-compensated ferrimagnetism through two-dimensional heterojunctions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
San-Dong Guo, Junjie He, Yee Sin Ang
In addition to altermagnets, fully-compensated ferrimagnets are another category of collinear magnetic materials that possess zero-net total magnetic moment and exhibit spin-splitting, making them promising for low-energy spintronics, high-density data storage and high-sensitivity sensors. Although many methods, such as alloying, external electric field, Janus engineering, ferroelectric field and spin ordering, have been proposed to achieve fully-compensated ferrimagnetism, these approaches either face experimental difficulties or produce a small spin-splitting or are volatile. Here, we propose to form vertical heterostructures by stacking two different but equally magnetized two-dimensional ferromagnetic materials. If an A-type antiferromagnetic ordering is satisfied, a fully compensated ferrimagnet can be formed. This vertical heterostructure approach is insensitive to lattice matching and stacking manner, thus being more conducive to experimental realization. Through first-principles calculations, we verify our proposal with several examples, focusing in particular on $ \mathrm{CrI_3}$ /$ \mathrm{CrGeTe_3}$ heterojunction composed of experimentally synthesized $ \mathrm{CrI_3}$ and $ \mathrm{CrGeTe_3}$ monolayers. The calculations show that $ \mathrm{CrI_3}$ /$ \mathrm{CrGeTe_3}$ is a fully-compensated ferrimagnet, with pronounced spin-splitting, and that tensile strain is more favorable for achieving fully-compensated ferrimagnetism. Our work provides an experimentally feasible strategy for realizing fully-compensated ferrimagnetism, thereby further advancing the development of this field.
Materials Science (cond-mat.mtrl-sci)
7 pages, 5 figures
RKKY interaction mediated by a spin-polarized 2D electron gas with Rashba and altermagnetic coupling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Magnetic interactions between impurity spins play a crucial role in determining magnetic configurations in spintronic systems. Using a Green’s function formalism, we investigate Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange interactions between two localized spins mediated by a two-dimensional electron gas arising from two spin-polarized bands with Rashba spin-orbit coupling (RSOC) and altermagnetic dispersion. We analyze two distinct regimes: (a) strong out-of-plane ferromagnetic order, and (b) weak in-plane order. For out-of-plane magnetization, the Heisenberg, Ising, and Dzyaloshinskii-Moriya (DM) exchange interaction terms exhibit oscillatory spatial modulations and asymptotically decay as $ 1/R^{2}$ with impurity separation. Besides, all exchange terms display beating-like patterns that can be tuned via the exchange coupling strength between conduction electrons and ferromagnetic ordering. The DM vector lies within the two-dimensional plane, with the DM interaction being odd in the RSOC strength, oscillatory, and increasing in magnitude with RSOC strength. In contrast, it is even in the out-of-plane Zeeman field strength and oscillatory. Furthermore, the Heisenberg interaction exhibits a non-linear dependence on the altermagnetic band parameter. In the case of weak in-plane order, the Heisenberg exchange interaction shows a non-linear dependence on the in-plane exchange coupling strength.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
15 pages, 10 figures
Topology-Driven Vibrations in a Chiral Polar Vortex Lattice
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Eric R. Hoglund, Harrison A. Walker, Peter Meisenheimer, Thomas W. Pfeifer, Niels De Vries, Dipanjan Chaudhuri, Ting-Ran Liu, Steven C. Quillin, Sandhya Susarla, De-Liang Bao, Patrick E. Hopkins, Andrew R. Lupini, Peter Abbamonte, Yu-Tsun Shao Ramamoorthy Ramesh, Sokrates T. Pantelides, Jordan A. Hachtel
The ordering of magnetic or electric dipoles leading to real-space topological structures is at the forefront of materials research as their quantum mechanical nature often lends itself to emergent properties. Atomic lattice vibrations (phonons) are often a key contributor to the formation of long-range dipole textures based on ferroelectrics and impact the properties of the emergent phases. Here, using monochromated, momentum-resolved electron energy-loss spectroscopy (qEELS) with nanometer spatial resolution and meV-spectral-precision, we demonstrate that polar vortex lattices in PbTiO$ _3$ spatially modulate the material’s vibrational spectrum in patterns that directly reflect the overlying symmetry of the topological patterns. Moreover, by combining experiments with molecular dynamics simulations using machine learned potentials we reveal how these structures modify phonon modes across the vibrational spectrum. Beyond simple intensity modulation, we find that the chirality of the vortex topology imparts its unique symmetry onto phonons, producing a distinctive asymmetrical spectral shift across the vortex unit cell. Finally, the high spatial resolution of the technique enables topological defects to be probed directly, demonstrating a return to trivial PbTiO$ _3$ modes at vortex dislocation cores. These findings establish a fundamental relationship between ferroelectric-ordering-induced topologies and phonon behavior, opening new avenues for engineering thermal transport, electron-phonon coupling, and other phonon-mediated properties in next-generation nanoscale devices.
Materials Science (cond-mat.mtrl-sci)
16 pages main text, 4 figures, 6 pages of methods, 3 pages of references, 1 extended figure, 7 supporting figures
An Orbit-qubit Quantum Processor of Ultracold Atoms
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-16 20:00 EDT
Ming-Gen He, Wei-Yong Zhang, Zhen-Sheng Yuan, Jian-Wei Pan
It is challenging to build scalable quantum processors capable of both parallel control and local operation. As a promising platform to overcome this challenge, optical lattices offer exceptional parallelism. However, it has been struggling with precise local operations due to relatively narrow lattice spacings. Here, we introduce a new quantum processor incorporating orbit-qubit encoding and internal states (as auxiliary degrees of freedom) to achieve spatially selective operations together with parallel control. With this processor, we generate one-dimensional and two-dimensional cluster states using minimal layers of controlled-Z gates. We experimentally detect the multipartite entanglement of a two-dimensional cluster state involving 123 orbit qubits through direct stabilizer measurements, verifying the full bipartite non-separability. Furthermore, we demonstrate measurement-based quantum computation by implementing single-qubit and two-qubit logical gates, highlighting the flexibility of orbit-qubit operations. Our results establish orbit-qubit optical lattices as a scalable quantum processing architecture, opening new pathways for quantum computation applications.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
9+8 pages, 5+4 figures
Gaussian fixed lines of $S=1/2$ XXZ chain with next-nearest neighbor interaction and $sl_2$ loop algebra
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Daiki Yomatsu, Kiyohide Nomura
Spin systems are important to understand various physical properties in quantum many-body systems. We numerically study the Gaussian fixed lines (GFLs) of the $ S=1/2$ XXZ chain with next-nearest neighbor (NNN) interaction in the XY phase. The GFLs are the set of points where the coefficient of the umklapp scattering vanishes. We show that the GFLs pass through the ``special points’’, which are defined as the points where the $ sl_2$ loop algebra symmetry governs in low-energy physics. In addition, we have discussed the Tomonaga-Luttinger parameter K, and the metamagnetism influences the shape of the GFLs.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
9 pages, 9 figures
Measuring pulse heating in Si quantum dots with individual two-level fluctuators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Feiyang Ye, Lokendra S. Dhami, John M. Nichol
To encode quantum information in semiconductor spin qubits, voltage pulses are necessary for initialization, gate operation, and readout. However, these pulses dissipate heat, shifting spin-qubit frequencies and reducing gate fidelities. The cause of this pulse heating in quantum-dot devices is unknown. Here, we measure pulse heating using charged two-level fluctuators (TLFs) in Si/SiGe quantum dots. We find that the TLFs are susceptible to pulse heating. The amount of heating depends on the pulse amplitude and frequency, but not on the distance between the pulsed gates and the TLFs. The amount of heating also generally depends on the idling voltage of the pulsed gates, suggesting that electrons accumulated under or near the gates contribute to the heating. We hypothesize that reducing the area of the gates with electrons nearby could mitigate the heating.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Sinusoidal Displacement Describes Disorder in CsPbBr3 Nanocrystal Superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Umberto Filippi, Stefano Toso, Matheus G. Ferreira, Lorenzo Tallarini, Yurii P. Ivanov, Francesco Scattarella, Vahid Haghighat, Huaiyu Chen, Megan O. Hill Landberg, Giorgio Divitini, Jesper Wallentin, Cinzia Giannini, Liberato Manna, Dmitry Baranov
Disorder is an intrinsic feature of all solids, from crystals of atoms to superlattices of colloidal nanoparticles. Unlike atomic crystals, in nanocrystal superlattices a single misplaced particle can affect the positions of neighbors over long distances, leading to cumulative disorder. This elusive form of collective particle displacement leaves clear signatures in diffraction, but little is known about how it accumulates and propagates throughout the superlattice. Here we rationalize propagation and accumulation of disorder in a series of CsPbBr3 nanocrystal superlattices by using synchrotron grazing incidence small- and wide-angle X-ray scattering. CsPbBr3 nanocrystals of colloidal softness S in the range of 0.3-0.7 were obtained by preparing particles with different sizes and ligand mixtures, consisting of oleic acid and primary amines of variable lengths. Most diffraction patterns showed clear signatures of anisotropic disorder, with multilayer diffraction characteristics of high structural coherence visible only for the {100} axial directions and lost in all other directions. As the softness decreased, the superlattices transitioned to a more ordered regime where small-angle diffraction peaks became resolution-limited, and superlattice multilayer diffraction appeared for the (110) diagonal reflections. To rationalize these anisotropies in structural coherence and their dependence on superlattice softness, we propose a sinusoidal displacement model where longitudinal and transverse displacements modulate nanocrystal positions. The model explains experimental observations and advances the understanding of disorder in mesocrystalline systems as they approach the limits of structural perfection.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft)
Partition function of the Kitaev quantum double model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Anna Ritz-Zwilling, Benoît Douçot, Steven H. Simon, Julien Vidal, Jean-Noël Fuchs
We compute the degeneracy of energy levels in the Kitaev quantum double model for any discrete group $ G$ on any planar graph forming the skeleton of a closed orientable surface of arbitrary genus. The derivation is based on the fusion rules of the properly identified vertex and plaquette excitations, which are selected among the anyons, i.e., the simple objects of the Drinfeld center $ \mathcal{Z}(\mathrm{Vec}_G)$ . These degeneracies are given in terms of the corresponding $ S$ -matrix elements and allow one to obtain the exact finite-temperature partition function of the model, valid for any finite-size system.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
39 pages, 15 figures
Carrier Density Dependence of Superconducting Transition Temperature in Electron-doped $\rm{SrTiO_3}$ Based on the First-principles Calculations
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-16 20:00 EDT
Riku Ikaida, Kazuhiro Sano, Yoshimi Masuda, Takuya Sekikawa, Yoshiaki Ōno
Electron-doped strontium titanate $ \rm{SrTiO_3}$ , known to be one of the most dilute superconductors, is investigated on the basis of the first-principles calculations. When the carrier density n decreases, the frequencies of the ferroelectric optical phonons near the $ \Gamma$ -point monotonically decreases in the overdoped regime with $ n<10^{20}/\rm{cm}^{3}$ , while unphysical imaginary phonon frequencies due to ferroelectric instabilities appear in the underdoped regime with $ n>10^{20}/\rm{cm}^{3}$ . We estimate the superconducting transition temperature $ T_{\rm{c}}$ by using the McMillan equation in the overdoped regime and find that $ T_{\rm{c}}$ increases with decreasing n as consistent with experiments in the overdoped regime. Detailed analysis of the Eliashberg function reveals that the increases in $ T_{\rm{c}}$ with decreasing n in the overdoped regime is mainly due to the contributions from the ferroelectric soft-mode optical phonons.
Superconductivity (cond-mat.supr-con)
R. Ikaida, K. Sano, Y. Masuda, T. Sekikawa, Y. Ono J. Phys. Soc. Jpn 94, 103701 (2025)
Electroluminescence of NV Color Centers in Diamond p-i-n Diodes mediated by Charge-state Dynamics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Ruirong Bai, Menglin Huang, Shanshan Wang, Shiyou Chen, Yu-Ning Wu
As the electroluminescence (EL) of NV color centers in diamond has been realized in p-i-n diodes,the underlying mechanism remains a puzzle for longer than a decade. In this study,using first-principles approaches,the electronic configurations and the possible transitions are comprehensively investigated. Based on the calculated carrier cross sections and transition rates,the mechanism of the EL of NV centers and the charge-state dynamics are revealed. The continuous EL is maintained by the cycle of NV0 ground (GNV0),NV+ metastable (MNV+) and NV0 excited state (ENV0). The weaker EL intensity compared to photoluminescence (PL) is explained by the bottleneck transition from MNV+ to ENV0 and another non-luminescent transition cycle. Additionally,our results also explain the disappearance of the luminescence of NV- as a result of unbalanced transitions between NV- and NV0. This study not only reveal the mechanism of electroluminescence of NV centers and explain experimental observations,but also provide first-principles insights to understand the charge-dynamics of other color centers under electric and optical field.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Spontaneous Twirls and Structural Frustration in Moiré Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Jingtian Shi, Gaurav Chaudhary, Allan H. MacDonald, Ivar Martin
Structural twirls form spontaneously in the domain wall networks of some moiré materials. We show that in heterobilayers, neighboring twirl chiralities tend to anti-align, forming staggered patterns that are well described by antiferromagnetic lattice $ \phi^4$ theories. In moiré systems with triangular domains, this leads to frustration in the chirality configuration of the structural twirls and to hysteresis with respect to variation of the average twist angle and possibly other control parameters.
Materials Science (cond-mat.mtrl-sci)
Fine Particle Percolation Dynamics in Porous Media
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
Dhairya R. Vyas, Richard M. Lueptow, Julio M. Ottino, Paul B. Umbanhowar
The influences of restitution coefficient, $ e_n$ , inter-particle friction, $ \mu$ , and size ratio, $ R$ , on gravity-driven percolation of fine particles through static beds of larger particles in the free-sifting regime ($ R \gtrsim 6.5$ ) remain largely unexplored. Here we use discrete element method simulations to study the fine particle percolation velocity, $ v_p$ , and velocity fluctuations, $ v_{rms}$ , for $ 7 \le R \le 50$ and a range of $ e_n$ and $ \mu$ . Increasing $ e_n$ increases velocity fluctuations and reduces percolation velocity. Increasing $ \mu$ decreases $ v_{rms}$ but its influence on $ v_p$ varies with $ v_{rms}$ , decreasing $ v_p$ for low $ v_{rms}$ and increasing $ v_p$ for high $ v_{rms}$ . Although the influence of size ratio is weaker, larger values of $ R$ increase both $ v_p$ and $ v_{rms}$ . We also assess the influence of different excitation mechanisms, specifically using static, randomly excited, and sheared beds, finding that an inverse correlation between $ v_p$ and $ v_{rms}$ persists across all cases and is well-described by the Drude model, where increased scattering reduces mobility, when $ v_{rms}$ is large. However, for weakly excited particles with low $ v_{rms}$ , the Drude analogy breaks down. In this regime, we introduce a staircase-inspired model that accounts for the gravitationally dominated percolation behavior. These findings provide fundamental insight into the mechanisms governing percolation dynamics in porous media and granular systems.
Soft Condensed Matter (cond-mat.soft)
Correlated interlayer quantum Hall state in alternating twisted trilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Dohun Kim, Gyeoul Lee, Nicolas Leconte, Seyoung Jin, Takashi Taniguchi, Kenji Watanabe, Jeil Jung, Gil Young Cho, Youngwook Kim
Trilayer graphene allows systematic control of its electronic structure through stacking sequence and twist geometry, providing a versatile platform for correlated states. Here we report magnetotransport in alternating twisted trilayer graphene with a twist angle of about 5$ ^{\circ}$ . The data reveal an electron-hole asymmetry that can be captured by introducing layer-dependent potential shifts. At charge neutrality ($ \nu_{\mathrm{tot}}=0$ ), three low-resistance states appear, which Hartree-Fock mean-field analysis attributes to emerging spin-resolved helical edge modes similar to those of quantum spin Hall insulators. At $ \nu_{\mathrm{tot}}=-1$ , we also observe suppressed resistance when the middle and bottom layers are each half filled while the top layer remains inert at $ \nu=-2$ , consistent with an interlayer excitonic quantum Hall state. These results demonstrate correlated interlayer quantum Hall phases in alternating twisted trilayer graphene, including spin-resolved edge transport and excitonic order.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Interaction-Driven Asymmetry in the Breakdown of the $ν$ = 1 Quantum Hall State
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Hoai Anh Ho, Jian Huang, L. N. Pfeiffer, K. W. West
We report real-time detection of longitudinal and transverse transport responses across distinct frequency bands in a ferromagnetic filling factor $ \nu$ = 1 integer quantum Hall state. By tuning $ \nu$ , we simultaneously access the evolution of the screening environment and bulk excitation structure. The resulting asymmetric breakdown, for $ \nu>1$ and $ \nu<1$ , reveals that interaction effects, rather than a single-particle band picture, dominate the transport instability. Our findings highlight the indispensability of electron-electron interactions even in integer quantum Hall phases, suggesting that distinct many-body entanglement structures underlie both integer and fractional topological phases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Amorphization-Mediated Si-I to Si-V Phase Transition and Reversible Amorphous-Si-V Phase Memory in Silicon Nanoparticles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Ziye Deng, Reza Namakian, Wei Gao
Molecular dynamics simulations using a Gaussian Approximation Potential (GAP) reveal a stress triaxiality driven, two-step Si-I (diamond cubic) to Si-V (simple hexagonal) phase transition pathway in a spherical Si nanoparticle with a 10 nm diameter under triaxial compression. A transient amorphous phase first forms at the surface and propagates inward around Si-I core, where stress triaxiality is low (shear-dominated). Within the amorphous shell, the material recrystallizes into Si-V at locations of elevated stress triaxiality and hydrostatic pressure. The resulting Si-V structure transforms into a fully amorphous state upon unloading. A subsequent loading-unloading cycle applied to this amorphous nanoparticle reveals a reversible amorphous to Si-V transformation, demonstrating a nanoscale phase memory effect.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Large Chern-Number Quantum Anomalous Hall Effect from Canted Antiferromagnetic Order in $d$-Electron System on Kagome Lattice
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Waquar Ahmed, Steffen Schaeffer, Pierre Lombardo, Roland Hayn, Imam Makhfudz
Electrons of $ d$ -symmetry in a kagome lattice are considered which interact with non-collinear antiferromagnetic order in the absence of spin-orbit coupling. The non-collinearity of spin texture gives rise to non-relativistic spin splitting and the associated intrinsic Berry curvature. The integral of the latter over the Brillouin zone becomes nontrivial for non-coplanar (canted) non-collinear spin order even without explicit on-site or transfer spin-orbit coupling. That gives rise to a nonzero (scalar) spin chirality, and a record value for the Chern number of $ C=\pm 5$ can appear when the Fermi level is in an appropriate gap for isotropic electron hopping integrals, or nearly isotropic ones. The numerical results for this topological quantum anomalous Hall effect are supported by an analytical formula. It is possible to split the $ C=\pm 5$ plateau into different possible nonzero values for the Chern number by varying the onsite energies. The topological phase transitions between Hall plateaus can be driven by flipping the Zeeman-like exchange field or controlling the onsite energies, alluding to the potential of this system to quantum information.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
6 pages main text + 8 pages supplementary materials
Bridging Structure and Activity in Nanocatalysts via Machine Learning and Global Structure Representations
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Sofia Zinzani, Francesca Baletto, Kevin Rossi
Establishing a mapping between nanocatalysts structure and their catalytic properties is essential for efficient design. To this end, we demonstrate the accuracy of a general machine learning framework on a representative and challenging application: predicting the mass activity of Pt nanoparticles for the electrochemical oxygen reduction reaction, estimated via a microkinetic model. Accurate models are obtained when leveraging either a nanocatalyst’s structure representation accessible at the computational level, namely the surface site generalized coordination number distributions, or one accessible experimentally, namely the nanoparticle’s pair distance distribution function. Building on this result, we demonstrate that our machine learning model, in tandem with Bayesian optimization, efficiently identifies the Top-10 and Top-100 most active structures out of a large pool of candidates comprising more than 50000 different structures, after probing the activity only of a few thousand structures. These findings provide a robust blueprint for accelerated theoretical and experimental identification of active nanocatalysts.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Absence of detectable spin and orbital pumping from Ni to Nb by out-of-plane ferromagnetic resonance
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Omolara A. Bakare, Galen T. Street, Sachli Abdizadeh, Rachel E. Maizel, Christoph Klewe, Satoru Emori
Excited ferromagnets can pump spin angular momentum, along with possibly orbital angular momentum. Among elemental ferromagnets, Ni has been proposed to exhibit substantial orbital pumping relative to spin pumping. Here, we search for a signature of orbital pumping by Ni, specifically by comparing out-of-plane ferromagnetic resonance in heterostructures without Ni (FeV/Nb) and with Ni (FeV-Ni/Nb). The FeV/Nb series shows a clear increase in Gilbert damping with the Nb sink thickness, attributed to spin pumping from FeV to Nb. Surprisingly, the FeV-Ni/Nb series exhibits no such damping increase, revealing no significant spin or orbital pumping from Ni to Nb. Our results offer a fresh perspective on angular-momentum transfer in Ni-based heterostructures, suggesting that the interpretation of some strong orbitronic effects may require further consideration.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Interplay between Hubbard interaction and charge transfer energy in three-orbital Emery model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
We use the numerically unbiased determinant quantum Monte Carlo (DQMC) method to systematically investigate the three-orbital Emery model in the normal state in a wide range of local interactions, charge transfer energy, and doping levels. We focus on the influence of the onsite Hubbard $ U_{dd}$ and charge transfer energy scale $ \epsilon_p$ on the electronic properties via the orbital occupancies, local moments, spin correlations, and spectral properties. Rich features of the orbital-resolved local and momentum-dependent spectra are revealed to associate with the possible Zhang-Rice singlet (ZRS) breakdown reflected by the peak splitting near the Fermi level in the heavily overdoped regime. Moreover, the pseudogap features at small charge transfer energy scale (relevant to cuprates) are shown to diminish at larger $ \epsilon_p$ , which implies the weakening or absence of the pseudogap in the infinite-layer nickelates. Besides, an optimal value of $ \epsilon_p$ is identified for maximizing the antiferromagnetic (AFM) spin correlations. Our large-scale simulations provide new insights on the well-established Emery model, particularly in the regime of heavily overdoped and/or large charge transfer energy scale.
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 8 figures
A Machine Learning Closure for Polymer Integral Equation Theory
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
Zhihao Feng, Christian T. Randolph, Tyler B. Martin, Thomas E. Gartner III
Polymer reference interaction site model (PRISM) theory, a descendent of Ornstein-Zernike liquid state theory, is a powerful tool to predict the structure and thermodynamics of equilibrium polymer systems, but its accuracy and applicability can be limited in some important cases. Typically, these shortcomings are traced to the analytical closure relationships used to solve the integral equations. Here, we propose a machine learning (ML)-based closure relation trained on a dataset of coarse-grained molecular dynamics simulations of homopolymer melts and solutions. PRISM theory with the ML closure outperforms traditional atomic closures (e.g., Percus-Yevick) in predicting the structure of typical coarse-grained model systems. We also use the ML closure to accurately model the results of small-angle neutron scattering experiments. This ML-enhanced PRISM theory can therefore enable rapid soft materials discovery and design efforts.
Soft Condensed Matter (cond-mat.soft)
15 pages, 3 figures. Includes supporting information with 10 additional figures
Planar Ballistic Electron Emission Spectroscopy for Single-Shot Probing of Energy Barrier Inhomogeneity at Junction Interface
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Jiwan Kim, Jaehyeong Jo, Jungjae Park, Hyunjae Park, Eunseok Hyun, Jisang Lee, Sejin Oh, Kibog Park
We propose an experimental methodology for probing the energy barrier inhomogeneity at the metal/semiconductor interface without the need for time-consuming microscopic survey. It is based on the known statistical nature of the interfacial energy barrier and the use of planar tunnel junction as an array of parallelly-connected ballistic electron emission microscopy (BEEM) tips. In order to analyze a lump of local BEEM signals, we incorporate the Tung model into the Bell-Kaiser theory. To validate our theoretical strategies, we investigate the interfacial energy barrier inhomogeneity of Pt/4H-SiC(0001) junction as a model system.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
17 pages, 8 figures
Topological excitonic insulators in electron bilayers modulated by twisted hBN
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Yongxin Zeng, Allan H. MacDonald, Nemin Wei
Equilibrium interlayer exciton condensation is common in bilayer quantum Hall systems and is characterized by spontaneous phase coherence between isolated layers. It has been predicted that similar physics can occur in the absence of a magnetic field in some two-dimensional semiconductor bilayers. In this work we consider the case of two transition metal dichalcogenide (TMD) monolayers separated by a twisted hexagonal boron nitride (hBN) bilayer or multilayer. The hBN layers suppress tunneling between the TMD layers so that phase coherence is spontaneous when it is present. When twisted, the hBN layers also form a ferroelectric moiré pattern that applies opposite triangular-lattice modulation potentials to the two TMD layers. We show via mean-field theory that at total hole filling per moiré unit cell $ \nu=1$ , this geometry can favor a chiral p-wave exciton condensate state in which the quantum anomalous Hall effect coexists with counter-flow superfluidity. We present a mean-field phase diagram for TMD hole bilayers modulated by twisted hBN, discuss the conditions needed for the realization of the p-wave condensate state, and propose experiments that could confirm its presence.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Synergetic Enhancement of Power Factors and Suppression of Lattice Thermal Conductivities via Biaxial Strain in ScAgSe$_2$ and TmAgTe$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Wu Xiong, Zhongjuan Han, Zhonghao Xia, Zhilong Yang, Jiangang He
The challenge of achieving high thermoelectric (TE) performance is mainly from the entanglement among Seebeck coefficient ($ S$ ), electrical conductivity ($ \sigma$ ), and lattice thermal conductivity ($ \kappa_{\mathrm{L}}$ ). In this work, we propose a synergetic strategy of enhancing power factor (PF, $ S^2\sigma$ ) and suppressing $ \kappa_{\mathrm{L}}$ by applying a biaxial tensile strain in two silver chalcogenides ScAgSe$ _2$ and TmAgTe$ _2$ with TlCdS$ 2$ -type structure. The forbidden $ p$ -$ d$ orbital coupling at the $ \Gamma$ point and allowed $ p$ -$ d$ orbital coupling at the A point and the middle of $ \Lambda$ line leads to high electronic band dispersion along the $ \Gamma$ -A direction and a high-degeneracy valence band valley ($ \Lambda_2$ ). The elongation of the Ag-Se bond under tensile strain weakens the orbital coupling between Ag-$ d$ and Se/Te-$ p$ orbitals and reduces the band energy at the A point, which aligns the valence band and achieving a high band degeneracy. Concurrently, the weaker Ag-Se/Ag-Te bond under a small tensile strain leads to lower phonon group velocity and strong three- and four phonon scatterings, leading to lower $ \kappa{\mathrm{L}}$ . Our first-principles calculations combined with electron-phonon coupling analysis as well as phonon and electron Boltzmann transport equations show that applying a 3% (2%) tensile strain can enhance the PF along the $ c$ -axis of ScAgSe$ _2$ (TmAgTe$ 2$ ) by 243% (246%) at a carrier concentration of 3$ \times$ 10$ ^{20}$ cm$ ^{-3}$ and reduce the $ \kappa{\mathrm{L}}$ by 37% (26%) at 300 K. Consequently, 2 $ \sim$ 4 times of $ ZT$ enhancement is obtained by 3% or 1% tensile strain in ScAgSe$ _2$ (TmAgTe$ _2$ ) at 300 K, achieving a maximum $ ZT$ of 3.10 (3.62) at 800 K. Our material design strategy based on molecular orbital analysis reveals an effective route to boosting TE performance, and can be extended to other systems as well.
Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures
Antiferromagnetic ordering and critical behavior induced giant magnetocaloric effect in distorted kagome lattice Gd$_3$BWO$_9$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Zhuoqun Wang, Xueling Cui, Tim Treu, Jiesen Guo, Xinyang Liu, Marvin Klinger, Christian Heil, Nvsen Ma, Xianlei Sheng, Zheng Deng, Xingye Lu, Xiancheng Wang, Wei Li, Philipp Gegenwart, Changqing Jin, Kan Zhao
We synthesize the high-quality Gd$ _3$ BWO$ 9$ single crystal and investigate its lowtemperature magnetic and thermodynamic properties. Below $ T\rm{N}$ = 1.08 K, the anisotropic behavior of magnetic susceptibilities reveals that the Gd$ ^{3+}$ moments exhibit the dominant antiferromagnetic coupling along the $ c$ -axis, while displaying a ferromagnetic arrangement in kagome plane. With pronounced magnetic frustration, in adiabatic demagnetization refrigeration experiments starting from initial conditions of 9 T and 2 K, Gd$ _3$ BWO$ 9$ polycrystal reaches a minimum temperature of 0.151 K, significantly lower than its $ T\rm{N}$ . Due to the high density of Gd$ ^{3+}$ ions ($ S$ =7/2), the maximum magnetic entropy change reaches over 50 J kg$ ^{-1}$ K$ ^{-1}$ under fields up to 7 T in Gd$ _3$ BWO$ _9$ , nearly 1.5 times as large as commercial sub-Kelvin magnetic coolant Gd$ _3$ Ga$ _5$ O$ _{12}$ (GGG). The H-T phase diagram of Gd$ _3$ BWO$ _9$ under $ H$ //$ c$ exhibits field-induced critical behavior near the phase boundaries. This observation aligns with the theoretical scenario in which a quantum critical point acts as the endpoint of a line of classical second-order phase transitions. Such behavior suggests the importance of further investigations into the divergence of magnetic Grüneisen parameter in the vicinity of critical field at ultralow temperatures.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
This manuscript contains 5 figures, to appear in Phys. Rev. Mater soon
Entropic active particle transport in pulsating 3D geometries
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
Rahul Sinha, Ankit Gupta, P. S. Burada
We study the transport of active Brownian particles (ABPs) in three-dimensional (3D) oscillatory geometries, which are spatially periodic. We establish a generalized Fick-Jacobs approach, which reduces a 3D system to an effective 1D system based on the assumption that a fast equilibration of particles along the transversal directions of the geometry. The transport characteristics of ABPs are computed semi-analytically and corroborated by numerical simulations. At the optimal frequency of the geometry oscillation, particles exhibit higher average velocity $ \langle v \rangle$ and effective diffusion coefficient $ D_{\text{eff}}$ , resembling the phenomena of stochastic resonance. This effect is further enhanced by the self-propelled velocity of ABPs and the amplitude of geometry oscillations. These findings have significant implications for the development of micro- and nanofluidic devices with enhanced control over particle transport and precise manipulation of small-scale biomedical devices.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
Dynamical Transitions in Trapped Superfluids Excited by Alternating Fields
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-16 20:00 EDT
The paper presents a survey of some dynamical transitions in nonequilibrium trapped Bose-condensed systems subject to the action of alternating fields. Nonequilibrium states of trapped systems can be realized in two ways, resonant and nonresonant. Under resonant excitation, several coherent modes are generated by external alternating fields, whose frequencies are tuned to resonance with some transition frequencies of the trapped system. A Bose system of trapped atoms with Bose-Einstein condensate can display two types of the Josephson effect, the standard one, when the system is separated into two or more parts in different locations or when there are no any separation barriers, but the system becomes nonuniform due to the coexistence of several coherent modes interacting with each other, which is termed internal Josephson effect. The mathematics in both these cases is similar. We concentrate on the internal Josephson effect. Systems with nonlinear coherent modes demonstrate rich dynamics, including Rabi oscillations, Josephson effect, and chaotic motion. Under Josephson effect, there exist dynamic transitions that are similar to phase transitions in equilibrium systems. The bosonic Josephson effect is shown to be realizable not only for weakly interacting systems, but also in superfluids, with not necessarily weak interactions. Sufficiently strong nonresonant excitation can generate several types of nonequilibrium states comprising vortex germs, vortex rings, vortex lines, vortex turbulence, droplet turbulence, and wave turbulence. Nonequilibrium states can be characterized and distinguished by effective temperature, effective Fresnel number, and dynamic scaling laws.
Quantum Gases (cond-mat.quant-gas)
30 pages, review
Physics 7 (2025) 41
Dislocation response to electric fields in strontium titanate: A mesoscale indentation study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Alexander Frisch, Daniel Isaia, Oliver Preuß, Xufei Fang
Dislocations in perovskite oxides have drawn increasing research interest due to their potential of tuning functional properties of electroceramics. Open questions remain regarding the behavior of dislocations concerning their stability under strong externally applied electric fields. In this study, we investigate the dielectric breakdown strength of nominally undoped SrTiO3 crystals after the introduction of high-density dislocations. The dislocation-rich samples are prepared using the Brinell scratching method, and they consistently exhibit lower dielectric breakdown strength as well as a larger scatter in the breakdown probability. We also study the impact of electric field on the introduction and movement of dislocations in SrTiO3 crystals using Brinell indentation coupled with an electric field of 2 kV/mm. No changes on the dislocation plastic zone size, depth, and dislocation distribution are observed under this electric field. Based on the charge state of the dislocations in SrTiO3 as well as the electrical and thermal conductivity modified by dislocations, we discuss the forces induced by the electric field to act on the dislocations to underline the possible mechanisms for such dislocation behavior.
Materials Science (cond-mat.mtrl-sci)
“Adiabatic” Elastic Constants in Hubbard-Corrected Density-Functional Theory DFT+U: case UO$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Mahmoud Payami, Samira Sheykhi
Since in DFT+U there are multiple self-consistent electronic solutions, the so called metastable states, the elastic constants computed from stress-vs-strain will be incorrect if some of the strained configurations fall into a different local electronic minimum than the equilibrium non-strained state. So, it is crucial to carefully take steps to keep the same electronic Hubbard occupation branch when computing the stresses for small strained geometries. In this work, we have explained this “adiabatic” method of calculation for elastic constants and applied for UO$ _2$ crystal described within two different unit cells of cubic 12-atom and tetragonal 6-atom basis sets. The calculation results for the two different unit cells are the same within 0.1 GPa, and agreement with experiment is excellent.
Materials Science (cond-mat.mtrl-sci)
5 pages, 3 figures, two-column RevTex
Viscous flow in glass-forming liquids: The twice-activation analysis and the bond wave model
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
The twice-activation method for analysis of experimental viscosity-temperature data reveals a set of interconnected parameters describing the state of the flowing glass-forming liquid in terms of convergation point which describes an infinite set of viscosity-temperature relations for the liquid considered. The observed uncertainty in the viscosity-temperature behavior permits to consider glass-forming liquid as the self-organizing system realizing by the bonds wave as dissipative pattern. The acoustic bond wave and the switching bond wave are considered generally and in different groups of glass-formers: inorganic, organic and polymers. The demonstrated correlation between two coordinates of convergation point and kinetic and thermodynamic measures of fragility permits to resolve the problem of the measures discrepancy.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
12 pages, 20 figures, 3 tables
Frustration-Enhanced Quantum Annealing Correction Models with Additional Inter-replica Interactions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Quantum annealing correction (QAC) models provide a promising approach for mitigating errors in quantum annealers. Previous studies have established that QAC models are crucial for ensuring the robustness of the ground state of the Ising model on hardware. In this work, the effects of QAC models incorporating replicas with additional interactions, specifically, the penalty spin model and the stacked model, are investigated for problems characterized by a small energy gap between the ground and first excited states during quantum annealing, a well-known bottleneck to reaching the ground state. The results demonstrate that these QAC models can obtain the optimal solution within short annealing times by exploiting diabatic transitions, even for problems with a small energy gap. These findings highlight the potential of QAC models as practical near-term algorithms for hardware subject to runtime limitations and control noise.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Glimpsing at Electron’s Form Factor through Quasiparticle Interference in Twisted Bilayer Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
D.-H.-Minh Nguyen, Francisco Guinea, Dario Bercioux
We show that characteristics of the electron’s form factor in two-dimensional materials are observable in quasiparticle interference (QPI) spectrum. We study QPI in twisted bilayer graphene using real-space tight-binding calculations combined with the kernel polynomial method, which agrees excellently with the form factor norm obtained from the continuum Hamiltonian. The QPI signals, displaying a chiral structure, reveal all distinct interference processes between states near the Dirac points. We propose pseudospin textures of twisted bilayer graphene to explain all the interference mechanisms. Our results provide microscopic insights into electronic eigenstates of twisted bilayer graphene and suggest QPI as a potential method for probing the form factor, which governs the material’s quantum geometry and many-body states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
16 pages, 10 figures
Intrinsic Quantum Clusters in Kagome Weyl Semimetal Co3Sn2S2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Yuqing Xing, Hui Chen, Li Huang, Roger Guzman, Qi Zheng, Senhao Lv, Jinan Shi, Haitao Yang, Wu Zhou, Hong-Jun Gao
Impurities and intrinsic point defects, which profoundly influence spin, charge, and topological degrees of freedom, are crucial parameters for tuning quantum states in quantum materials. The magnetic Weyl semimetal Co3Sn2S2 with its strong spin-orbit coupling, intrinsic ferromagnetism, and kagome lattice of correlated electrons, provides a compelling platform for studying impurity excited states. Yet, the role of intrinsic impurities in shaping its quantum states remains elusive. Here, we uncover intrinsic quantum clusters-localized intrinsic point defects that act as tunable quantum perturbations capable of reshaping electronic states and order parameters, on the surface of Co3Sn2S2 via scanning tunneling microscopy/spectroscopy and non contact atomic force microscopy, combined with scanning transmission electron microscopy/electron energy loss spectroscopy. These clusters are identified as native oxygen defects that dominate the intrinsic defect landscape on both cleaved surface terminations. On the Sn-terminated surface, oxygen impurities occupy hollow sites between three Sn atoms, and tune the flat band near the Fermi level, which exhibits orbital magnetism induced unconventional Zeeman effect under an applied magnetic field. On the S-terminated surface, oxygen interstitials reside slightly off center relative to the S lattice and generate occupied impurity states that retain sixfold symmetry at higher energies but reduce to C2 symmetry at lower energies. In contrast, these impurity states show no measurable magnetic response. Our findings establish that intrinsic oxygen-related quantum clusters act as tunable local perturbations in a topological kagome magnet, offering a versatile platform to probe and engineer impurity-driven phenomena in correlated and topological systems.
Materials Science (cond-mat.mtrl-sci)
Achieving DFT accuracy in short range ordering and stacking fault energy using moment tensor potential for CoCrFeNi and CoCrNi
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Mashroor S. Nitol, Artur Tamm, Subah Mubassira, Shuozhi Xu, Saryu J. Fensin
Medium-entropy alloys (MEAs) such as CoCrFeNi and CoCrNi are promising structural materials owing to their outstanding mechanical and thermal properties, which arise from complex chemical disorder and atomic-scale interactions. Although density functional theory (DFT) has provided fundamental insights into these systems, its high computational cost limits exploration of large-scale phenomena. Classical interatomic potentials have been used to address this gap but often lack the fidelity needed to capture many-body interactions and chemical short-range ordering (CSRO) effects. In this work, we developed a machine-learned Moment Tensor Potential (MTP) to bridge accuracy and efficiency. The MTP was trained on a comprehensive DFT database spanning unary to quaternary configurations and reproduces energies, forces, and stresses with near-DFT accuracy across diverse structural and chemical environments. It accurately predicts elastic properties and recovers compositional trends in bulk and shear moduli in agreement with DFT. Hybrid Monte Carlo/molecular dynamics simulations capture CSRO, reproducing key DFT-reported features including Cr-Cr and Fe-Fe repulsion and Ni-Cr ordering. Stacking fault energetics were modeled, yielding ISF energies near 54 mJ/m2 for CoCrNi and 36 mJ/m2 for CoCrFeNi, consistent with DFT predictions. Local chemical environment effects on stacking faults were also resolved: Co-rich planes reduce, whereas Cr- or Fe-rich planes increase, the stacking fault energy. By enabling large-scale, high-fidelity simulations at a fraction of DFT’s cost, the developed MTP provides a robust framework for predictive modeling of thermodynamic stability, defect behavior, and mechanical response of FCC MEAs.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Realization of large magnetocaloric effect in the Kagome antiferromagnet Gd3BWO9 for Sub-Kelvin cryogenic refrigeration
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Fangyuan Song, Xinyang Liu, Chao Dong, Jin Zhou, Xinlong Shi, Yuyan Han, Langsheng Ling, Huifen Ren, Songliu Yuan, Shun Wang, Junsen Xiang, Peijie Sun, Zhaoming Tian
Rare-earth (RE) based frustrated magnets have attracted great attention as excellent candidates for magnetic refrigeration at sub-Kelvin temperatures, while the experimental identification on systems exhibiting both large volumetric cooling capacity and reduced working temperatures far below 1 K remain to be a challenge. Here, through the ultra-low temperature magnetism and thermodynamic characterizations, we unveil the large magnetocaloric effect (MCE) realized at sub-Kelvin temperatures in the frustrated Kagome antiferromagnet Gd3BWO9 with TN1.0 K. The isothermal magnetization curves indicate the existence of field (B) induced anisotropic magnetic phase diagrams, where four distinct magnetic phases for B // c-axis and five magnetic phases for B // ab-plane are identified at T< TN. The analysis of magnetic entropy S(B, T) data and direct adiabatic demagnetization tests reveal a remarkable cooling performance at sub-Kelvin temperatures featured by a large volumetric entropy density 502.2 mJ/K/cm3 and a low attainable minimal temperature Tmin168 mK from the initial cooling condition of 2 K and 6 T, surpassing most of Gd-based refrigerants previously documented in temperature ranges of 0.25-4 K. The realized Tmin~168 mK far below TN ~ 1.0 K in Gd3BWO9 is related to the combined effects of magnetic frustration and criticality-enhanced MCE, which together leave a substantial magnetic entropy at reduced temperatures by enhancing spin fluctuations.
Strongly Correlated Electrons (cond-mat.str-el)
Weak-coupling theory for partial condensation of mobile excitons
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
We studied formation of charge density wave between valleys in a system with a double-well-like dispersive valence band relevant for the rhombohedral graphene trilayer. In a regime with 2 Fermi surfaces, electron- and hole-like: one of radius $ p_i$ , another of $ p_o$ , an instability in particle-hole channel appears at $ q=q_c+\delta q$ , where $ q_c=p_o-p_i$ . In a weak coupling regime ($ x/\epsilon_F\ll 1$ ) presence of an additional energy scale $ \propto m q_c\delta q$ gives rise to several regimes with distinct spectrum and transport properties: in a regime with small order parameter $ x\lessapprox m p_F \delta q$ Fermi arcs show up and substantially change conductance. At larger values of the order parameter Fermi arcs are gapped out. Regimes are also distinguished by different effective exponents $ \gamma$ in conductance correction $ \sigma\propto \tau_D^\gamma$ where $ \tau_D$ is scattering time off disorder and $ 1\leq\gamma\leq 2$ .
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Mean first-passage time of a run-and-tumble particle with exponentially-distributed tumble duration in the presence of a drift
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
We consider a run-and-tumble particle on a finite interval $ [a,b]$ with two absorbing end points. The particle has an internal velocity state that switches between three values $ v,0,-v$ at exponential times, thus incorporating positive tumble times. Moreover, a constant drift is added to the run-and-tumble motion at all times. The combination of these two features constitutes the main novelty of our model. The densities of the first-passage time through $ a$ (given the initial position and velocity states) satisfy certain forward Fokker–Planck equations. The Laplace transforms of these equations induce evolution equations for the exit probabilities and the mean first-passage times of the particle. We solve these equations explicitly for all possible initial states. We consider the limiting regimes of instantaneous tumble and/or the limit of large $ b$ tend to infinity to confirm consistency with existing results in the literature. In particular, in the limit of a half-line (large $ b$ ), the mean first-passage time conditioned on the exit through $ a$ is an affine function of the initial position if the drift is positive, as in the case of instantaneous tumble.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
49 pages, 4 figures
Optimizing optimal transport: Role of final distributions in finite-time thermodynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Kaito Tojo, Rihito Nagase, Ken Funo, Takahiro Sagawa
Performing thermodynamic tasks within finite time while minimizing thermodynamic costs is a central challenge in stochastic thermodynamics. Here, we develop a unified framework for optimizing the thermodynamic cost of performing various tasks in finite time for overdamped Langevin systems. Conventional optimization of thermodynamic cost based on optimal transport theory leaves room for varying the final distributions according to the intended task, enabling further optimization. Taking advantage of this freedom, we use Lagrange multipliers to derive the optimal final distribution that minimizes the thermodynamic cost. Our framework applies to a wide range of thermodynamic tasks, including particle transport, thermal squeezing, and information processing such as information erasure, measurement, and feedback. Our results are expected to provide design principles for information-processing devices and thermodynamic machines that operate at high speed with low energetic costs.
Statistical Mechanics (cond-mat.stat-mech)
17pages, 3 figures
Electron Hydrodynamics in Graphene : Experimental and Theoretical Status
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Subhalaxmi Nayak, Cho Win Aung, Thandar Zaw Win, Ashutosh Dwibedi, Sabyasachi Ghosh, Sesha Vempati
The present work comprehensively reviews electron hydrodynamics in graphene, highlighting both experimental observations and theoretical developments. Key experimental signatures such as negative vicinity resistance, Poiseuille flow, and significant violation of the Wiedemann-Franz (WF) law have been discussed, with special emphasis on Lorenz ratio measurements. In the theoretical direction, recent efforts have focused on developing hydrodynamic frameworks for calculating the thermodynamic and transport coefficients of electrons in graphene. The present work has briefly addressed the theoretical framework adopted by our group.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Pristine and transition metal doped 2D AlSb as high performance electrocatalyst for selective CO2 reduction: A first-principles study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Md. Mostaqul Islam, Ahmed Zubair
Electrochemical CO2 reduction reaction (CO2RR) using 2D nanomaterials has emerged as a sophisticated approach to mitigate industrial CO2 emissions. In this work, the potential application of pristine as well as strategically Fe, Co, Ni-doped 2D AlSb was examined as a CO2RR electrocatalyst. The recation pathways of CO2RR intermediate complexes, overpotential, stability, efficiency, and selectivity were studied using density functional theory (DFT). Outstanding overpotentials were achieved with pristine and doped 2D AlSb: Ni-doped 2D AlSb was selective for HCOOH (0.12eV) and CH4 (0.28eV), and Fe-doped 2D AlSb for HCHO (0.31eV) and CH3OH (0.31eV). The opposing effects of hydrogen evolution reaction (HER) was mitigated with the application of electric potential and solution pH. The main reasons for the enhancement of catalytic effect due to doping with Fe, Co, and Ni are bandgap reduction and creation of states at the edge of the valence band due to the 3d orbitals of these dopants. Interestingly, the Fe-doped 2D AlSb catalyst exhibited the highest catalytic activity. Excellent electrocatalytic properties of pristine and doped 2D AlSb make them suitable as CO2RR catalysts contributing towards a green and sustainable energy ecosystem.
Materials Science (cond-mat.mtrl-sci)
Localizing Individual Exciton on a Quantum Hall Antidot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Rui Pu, Naomi Mizuno, Fernando Camino, Runchen Li, Kenji Watanabe, Takashi Taniguchi, Dmitri Averin, Xu Du
Quantum Hall systems host quasiparticles demonstrating correlated electron physics and non-trivial quantum statistics. Excitonic phases, archetypical for interaction effect, have attracted significant interest in recent years in double-layer quantum Hall systems where spatially separated electrons and holes form bosonic condensate through Coulomb interaction. Here, employing the approach of quantum Hall antidot with two spatially separated edge channels, we demonstrate a new type of quantum Hall quasiparticle exciton which represents a quantum-coherent bound state of an electron and a hole situated on their corresponding edges coupled through intralayer tunneling and Coulomb interaction. Quantum-coherent dynamics of the exciton is reflected in the observed evolution of the position and magnitude of the antidot conductance peaks around the electron-hole resonance. The quantum Hall antidot setup allows localization and electrical tuning of individual quantum Hall excitons. Quantum superposition of vacuum- and electron-hole pairing states is observed through the gate-dependent tunneling conductance of the antidot. Modeling the electron-hole pair as a coupled two-level system, semi-quantitative understanding of experimental observations is achieved. This work opens avenues for creating quantum systems of multiple quantum Hall quasiparticles.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Si-Substituted MAX Phases and In-Situ Formation of Si-coated MXene Composites via Chlorosilane Etching
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Xudong Wang, Qian Fang, Mian Li, Zhifang Chai, Qing Huang
Silicon-based MAX phases are a promising class of layered ceramics with superior thermal and chemical stability. However, their synthesis remains challenging due to inherent thermodynamic instability at high temperatures. Herein, we develop a general top-down strategy to synthesize a broad family of Si-substituted MAX phases (M = Ti, V, Nb, Ta, Cr; X = C, N) by reacting Al-based MAX precursors with SiCl4 vapor. This approach not only circumvents traditional high-temperature limitations but also enables precise A-site defect engineering, resulting in phases with controlled vacancy concentrations (e.g., Nb2Si3/4C and Nb2Si1/2C). Furthermore, we introduce a redox potential-based model that rationalizes the reaction pathway. Using Tin+1AlXn etched with SiCl4 as an example, the process simultaneously forms Cl-terminated MXene (Mn+1XnCl2) and amorphous nano-Si, enabling the one-step synthesis of Si-coated MXene composites. This methodology provides new avenues for designing advanced MAX phases and MXene-based hybrids with tailored functionalities for applications in energy storage and catalysis.
Materials Science (cond-mat.mtrl-sci)
Phases and phase transitions of an $S=3/2$ chain on metallic and semi-metallic surfaces
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Motivated by recent scanning tunneling microscopy experiments on chains of Co adatoms on Cu surfaces, we investigate the physics of a spin-$ 3/2$ Heisenberg chain with single-ion anisotropy ($ D$ ) on metallic and semi-metallic surfaces. In the strong Kondo coupling ($ J_k$ ) limit, a perturbative analysis maps the system onto a Haldane spin-1 chain with single-ion anisotropy, ferromagnetically coupled to the metallic surface. This Haldane state, arising from underscreening of the $ S=3/2$ chain, is stable against small $ D$ and characterized by topological edge modes. The nature of the $ D$ -driven transitions out of this state depends on the environment. Coupling to a metal (semi-metal) is a relevant (irrelevant) perturbation at the decoupled fixed point between the spin-1 chain and the two-dimensional electron gas. In the large positive $ D$ limit, the system maps onto an anisotropic spin-$ 1/2$ Kondo system. For large negative $ D$ , in the Ising phase, spins are frozen. For small $ J_k$ , the nature of the metallic phase dominates. On a two-dimensional semi-metal, the Kondo coupling is irrelevant at the decoupled fixed point ($ J_k= 0$ ), leading to a Kondo breakdown phase at weak coupling, irrespective of $ D$ . In contrast, on a two-dimensional metal, the resulting dissipative Ohmic bath is a marginally relevant perturbation, inducing antiferromagnetic ordering along the chain. In this case, $ D$ drives a spin-flop transition between Ising and XY ordered phases. At $ D=0$ , we observe continuous transitions between the Kondo breakdown or dissipation-induced long-range ordered phases and the underscreened Haldane phase. These phase diagrams are supported by scaling arguments and sign-free auxiliary-field quantum Monte Carlo simulations.
Strongly Correlated Electrons (cond-mat.str-el)
21 pages, 27 figures
Nonreciprocal constitutive laws for oriented active solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
Balázs Németh, Takuya Kobayashi, Ronojoy Adhikari
We present an overdamped continuum description of oriented active solids in which interactions respect the symmetries of space but do not obey the principle of action and reaction. Taking position and orientation as kinematic variables, we examine the conservation of the linear and angular momentum variables in an elementary volume. We find that nonreciprocal interactions yield, in addition to the areal stresses and moment stresses of classical elasticity, volumetric forces and torques that act as local sources of momentum and angular momentum. Since, by symmetry, these can only depend on the strains, nonreciprocity requires the extension of constitutive modeling to strain-dependent volumetric forces and torques. Using Cartan’s method of moving frames and Curie’s principle, we derive the materially linear constitutive law that underpins the nonreciprocal, geometrically nonlinear elasticity of the continuum. We study this constitutive law exhaustively for a one-dimensional active solid and identify striking nonreciprocal effects - traveling waves, linear instabilities, spontaneous motion of and about the center of mass - that are absent in a passive, reciprocally interacting solid. Numerical simulations of a particulate active solid model, consisting of a linear assembly of hydrodynamically interacting active particles, yields long-wavelength behavior that is in excellent agreement with theory. Our study provides the foundation for a principled macroscopic mechanics of oriented active solids with symmetry-invariant, nonreciprocal microscopic interactions.
Soft Condensed Matter (cond-mat.soft)
25 pages, 8 figures
Geometric Analysis of Magnetic Labyrinthine Stripe Evolution via U-Net Segmentation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Vinícius Yu Okubo, Kotaro Shimizu, B.S. Shivaran, Gia-Wei Chern, Hae Yong Kim
Labyrinthine stripe patterns are common in many physical systems, yet their lack of long-range order makes quantitative characterization challenging. We investigate the evolution of such patterns in bismuth-doped yttrium iron garnet (Bi:YIG) films subjected to a magnetic field annealing protocol. A U-Net deep learning model, trained with synthetic degradations including additive white Gaussian and Simplex noise, enables robust segmentation of experimental magneto-optical images despite noise and occlusions. Building on this segmentation, we develop a geometric analysis pipeline based on skeletonization, graph mapping, and spline fitting, which quantifies local stripe propagation through length and curvature measurements. Applying this framework to 444 images from 12 annealing protocol trials, we analyze the transition from the “quenched” state to a more parallel and coherent “annealed” state, and identify two distinct evolution modes (Type A and Type B) linked to field polarity. Our results provide a quantitative analysis of geometric and topological properties in magnetic stripe patterns and offer new insights into their local structural evolution, and establish a general tool for analyzing complex labyrinthine systems.
Materials Science (cond-mat.mtrl-sci), Computer Vision and Pattern Recognition (cs.CV)
15 pages, 13 figures. This manuscript has been submitted to IEEE Access for possible publication. It has not yet been peer reviewed or accepted
Electro-nuclear quantum phase transition in TmVO$_4$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Mark P. Zic, Chao Huan, Nicolas Silva, Yuntian Li, Mark W. Meisel, Ian R. Fisher
Hyperfine interactions couple nuclear and electronic degrees of freedom. The present work explores how hyperfine coupling within the Tm ions in TmVO$ _4$ single crystals affects an electronic ferroquadrupole ordered ground state and its associated field-tuned quantum phase transition. For temperatures below the hyperfine energy scale, the nuclear moments reduce the critical field for the electronic order, resulting in a dramatic back-bending of the phase boundary delineating the ferroquadrupole order. This behavior is well described by a single-ion semiclassical mean-field model. Moreover, analysis of the effective Hamiltonian leads to a prediction of spontaneous nuclear magnetic order mediated by 4$ f$ electrons, which in principle persists with the application of orthogonal antisymmetric strain, yielding a proposed electro-nuclear tetracritical point.
Strongly Correlated Electrons (cond-mat.str-el)
Generalization of the Affleck-Kennedy-Lieb-Tasaki Model for Quantum Ferromagnetism
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
We generalize the Affleck-Kennedy-Lieb-Tasaki model to a spin-(S) ferromagnetic model with exactly-written ground states, known as the partially-magnetized valence bond solid (VBS) states with magnetization $ m=(S-1)/S$ .
We find that the VBS state and an antiferromagnetic ground state with magnetization $ m=0$ are degenerate for $ S=3/2$ and $ S=2$ by using the Lanczos method and the density matrix renormalization group method (DMRG).
However, increasing $ S$ , the magnetization of the ground states is uniquely determined as the fraction $ m=(S-1)/S$ .
This is not just a ferromagnet, but a quantum ferromagnet due to quantum entanglement inherent in VBS states.
In the low-energy excitation spectrum, we find the coexistence of the Haldane gap and Goldstone-like ferromagnetic magnon excitation.
This ``magnetic chimera’’ clearly appears under a finite magnetic field.
Finally, we discuss an application to the measurement-based quantum computation and an extension of the Haldane’s conjecture.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
Evidence for the Meissner effect in the nickelate superconductor La3Ni2O7-delta single crystal using diamond quantum sensors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-16 20:00 EDT
Lin Liu, Jianning Guo, Deyuan Hu, Guizhen Yan, Yuzhi Chen, Lunxuan Yu, Meng Wang, Xiao-Di Liu, Xiaoli Huang
Quantum sensing with nitrogen-vacancy (NV) centers in diamond enables the characterization of magnetic properties in the extreme situation of tiny sample with defects. Recent studies have reported superconductivity in La3Ni2O7-delta under pressure, with zero-resistance near 80 K, though the Meissner effect remains debated due to low superconducting volume fractions and limited high-pressure magnetic measurement techniques. In this work, we use diamond quantum sensors and four-probe detection to observe both zero resistance and the Meissner effect in the same La3Ni2O7-delta single crystal. By mapping the Meissner effect, we visualized superconducting regions and revealed sample inhomogeneities. Our combined magnetic and electrical measurements on the same crystal provide dual evidence of superconductivity, supporting the high-temperature superconductivity of La3Ni2O7-delta. This study also offers insights into its structural and magnetic properties under high pressure.
Superconductivity (cond-mat.supr-con)
16 pages, 5 figures
Orbital Hybridization-Driven Stabilization and Reactivity on an Asymmetrically Reconstructed Polar CeO2(100) Surface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Songda Li, Chen Zou, Liuxi Chen, Zhong-Kang Han, Wentao Yuan, Hangsheng Yang, David J. Wales, Yong Wang
Understanding and controlling the atomic structure of polar oxide surfaces is essential for unraveling surface reactivilty and designing advanced catalytic materials. Among these, the polar CeO2(100) surface is a prototypical and industrially important system in heterogeneous catalysis. However, due to the vast complexity of the surface configurations, its reconstruction behavior remains an open question. Here, we report a previously unidentified asymmetric (1x2) reconstructed structure on the CeO2(100) surface, discovered through an integrated approach that combines global structure search algorithms, machine learning-based atomic potential models, density functional theory (DFT) calculations, and in situ scanning transmission electron microscopy (STEM). The reconstructed surface is both thermodynamically and kinetically stable, characterized by an alternating arrangement of Ce3+ and Ce4+ ions, increased interlayer spacing, and reconfigured surface oxygen atoms. Importantly, the formation of localized Ce3+ polarons introduces occupied 4f states that strongly hybridize with surface O 2p orbitals, resulting in new occupied electronic states below the Fermi level. This orbital hybridization activates the O 2p states, enhances their electron-donating capacity, and facilitates the dissociation of adsorbed molecules such as H2O. These findings reveal a fundamental orbital-mediated mechanism by which surface reconstruction governs electronic structure and reactivity, offering critical insights and a new design strategy for tuning catalytic performance on polar oxide surfaces.
Materials Science (cond-mat.mtrl-sci)
23 pages, 9 figures. Under review at Physical Review Letters
Resetting Induces Memory Loss in Non-Markovian Processes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Stochastic resetting is a powerful strategy known to accelerate the first-passage time statistics of stochastic processes. While its effects on Markovian systems are well understood, a general framework for non-Markovian dynamics is still lacking, mostly due to its mathematical complexity. Here, we present an analytical and numerical framework to study non-Markovian processes under resetting, focusing on the first-passage properties of escape kinetics from metastable states. We show that resetting disrupts the inherent time correlation, inducing Markovianity, thereby leading to an efficient escape mechanism. This work, therefore, provides a much needed theoretical approach for incorporating resetting into complex chemical and biological processes, which follow non-Markovian dynamics.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
29 pages, 6 figures
Direct imaging reveals electromechanical ionic memory in 2D nanochannels
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Kalluvadi Veetil Saurav, Nathan Ronceray, Baptiste Coquinot, Agustin D. Pizarro, Ashok Keerthi, Theo Emmerich, Aleksandra Radenovic, Boya Radha
Nanofluidic memristors promise brain-inspired information processing with ions, yet their microscopic origin remains debated. So far, ionic memory has been attributed to ion-specific interactions, dynamic wetting, chemical reactions or mechanical deformations, yet typically without direct evidence. Here, by combining operando interferometric imaging with electrokinetic measurements, we directly visualize voltage-induced blistering of the confining walls of two-dimensional (2D) nanochannels, as key origin of memristive hysteresis. We identify two distinct classes of blisters: unidirectional, driven by electrostatic forces on surface charges, and bidirectional, arising from osmotic pressure due to concentration polarization. This mechanistic framework explains device evolution and device-to-device variability, and reframes stochastic blistering as a functional design element. Our results constitute a direct proof of electromechanical coupling as a robust pathway to ionic memory in 2D nanochannels and open routes toward high-performance ionic memristors and electrically actuated nanofluidic valves.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft)
Schrödinger-invariance in the voter model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Malte Henkel, Stoimen Stoimenov
Exact single-time and two-time correlations and the two-time response function are found for the order-parameter in the voter model with nearest-neighbour interactions. Their explicit dynamical scaling functions are shown to be continuous functions of the space dimension $ d>0$ . Their form reproduces the predictions of non-equilibrium representations of the Schrödinger algebra for models with dynamical exponent $ \mathpzc{z}=2$ and with the dominant noise-source coming from the heat bath. Hence the ageing in the voter model is a paradigm for relaxations in non-equilibrium critical dynamics, without detailed balance, and with the upper critical dimension $ d^\ast=2$ .
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph)
Latex 2e, 1 + 27 pages, 4 figures
Improving the efficiency of finite-time memory erasure with potential barrier shaping
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Erasure of the binary memory, 0 or 1, is an essential step for digital computation as it involves irreversible logic operations. In the classical case, the erasure of a bit of memory is accompanied by the evolution of a minimum amount of heat set by the Landauer bound kTln2, which can be achieved in the asymptotic limit. However, the erasure of memory needs to be completed within a finite time for practical and effective computational processes. It is observed that the higher the speed of erasure, the greater the amount of heat released, which leads to unfavorable environmental conditions. Therefore, this is a fundamental challenge to reduce the evolved heat related to finite-time memory erasure. In the present work, we address this crucial aspect in the field of information thermodynamics, where the two memory states correspond to the two wells of a bistable potential, as in the conventional cases. However, the potential is asymmetric in terms of the width of the two wells. Moreover, the two memory states are separated by a barrier that is asymmetric in structure. We examine in detail the effect of the degree of asymmetry on the success rate of the erasure process and the work done or heat released associated with it. We find that the asymmetry in the potential barrier partitioning the two memory states plays a very significant role in improving the efficiency of the erasure process, in view of the success rate and the thermodynamic costs.
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 15 figures
Exchange and spin-orbit proximity driven topological and transport phenomena in twisted graphene/CrI$_3$ heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
M. Jafari, M. Gmitra, A. Dyrdał
We present results of comprehensive first-principles and kp-method studies of electronic, magnetic, and topological properties of graphene on a monolayer of CrI$ _3$ . First, we identify a twist angle between the graphene and CrI$ _3$ , that positions the graphene Dirac cones within the bandgap of CrI$ _3$ . Then, we derive the low-energy effective Hamiltonian describing electronic properties of graphene Dirac cones. Subsequently, we examine anomalous and valley Hall conductivity and discuss possible topological phase transition from a quantum anomalous Hall insulator to a trivial insulating state, concomitant a change in the magnetic ground state of CrI$ _3$ . These findings highlight the potential of strain engineering in two-dimensional van der Waals heterostructures for controlling topological and magnetic phases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
10 pages, 6 figures
Dual-mode operation of ring-shaped spin Hall magnetoresistance sensor with biaxial sensing capability
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Jiayi Xu, Yuxin Si, Jiaqi Wang, Tingxuan Zhang, Zhenfei Hou, Yihong Wu
We present a spin Hall magnetoresistance sensor based on a NiFe/Pt multiring bridge structure, which exhibits high sensitivity and good linearity in two perpendicular directions within the sensor plane. Under DC excitation, it responds linearly to magnetic field perpendicular to the current direction, whereas AC excitation enables a linear response with near-zero offset to magnetic field aligned with the current direction, driven by spin-orbit torque effect. Moreover, the AC excitation effectively mitigates low-frequency 1/f noise down to sub-microvolt per sqrt(Hz) at 1 Hz. Systematic investigations have been performed to optimize the NiFe thickness while keeping the Pt thickness at 2 nm. The biaxial sensing capability offers a promising approach for multidimensional magnetic field detection in advanced sensing applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
On Magnetic and Crystal Structures of NiO and MnO
New Submission | Other Condensed Matter (cond-mat.other) | 2025-09-16 20:00 EDT
The magnetic and crystal structures of manganese and nickel monoxides have been studied by high-resolution neutron diffraction. The known 1$ k$ -structures based on the single propagation vector $ \left[\tfrac{1}{2}\ \tfrac{1}{2}\ \tfrac{1}{2}\right]$ for the parent paramagnetic space group $ Fm\bar{3}m$ are forced to have monoclinic magnetic symmetry and are not possible in rhombohedral symmetry. However, the monoclinic distortions from the rhombohedral $ R\bar{3}m$ metric allowed by symmetry are very small, and the explicit monoclinic splittings of the diffraction peaks have not been experimentally observed. We analyze the magnetic crystallographic models metrically compatible with our experimental data in full detail by using the isotropy subgroup representation approach, including rhombohedral solutions based on the propagation vector star $ \left{ \left[\tfrac{1}{2}\ \tfrac{1}{2}\ \tfrac{1}{2}\right],\ \left[-\tfrac{1}{2}\ \tfrac{1}{2}\ \tfrac{1}{2}\right],\ \left[\tfrac{1}{2}\ -\tfrac{1}{2}\ \tfrac{1}{2}\right],\ \left[\tfrac{1}{2}\ \tfrac{1}{2}\ -\tfrac{1}{2}\right] \right}$ . Although the full star rhombohedral $ R\bar{3}c$ structure can equally well fit our diffraction data for NiO, we conclude that the best solution for the crystal and magnetic structures for NiO and MnO is the 1$ k$ -monoclinic model with the magnetic space group $ C_c2/c$ (BNS 15.90, UNI symbol $ C2/c.1’_c[C2/m]$ ).
Other Condensed Matter (cond-mat.other), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Acta Cryst. (2024). B80, 385-392
Controlled growth of polar altermagnets via chemical vapor transport
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Hiraka Haruhiro, Raktim Datta, Poonam Yadav, Anzar Ali, Suheon Lee, Matthias J. Gutmann, Duhee Yoon, Dirk Wulferding, Xianghan Xu, Moon-Ho Jo, Sang-Wook Cheong, Sungkyun Choi
Altermagnetic properties have been recently proposed in polar magnetic oxides, M$ _{2}$ Mo$ _{3}$ O$ _{8}$ (M = Mn, Fe, Co, Ni), where improved characteristics of stronger magnetoelectric coupling and higher magnetic transition temperatures were observed. Thus, understanding their microscopic origins is of fundamental and technological importance. However, the difficulty in growing large single crystals hinders detailed experimental studies. Here, we report the successful growth of large single crystals of the pyroelectric antiferromagnet using two representative compounds, Fe$ _{2}$ Mo$ _{3}$ O$ _{8}$ and NiZnMo$ _{3}$ O$ _{8}$ . Growth was optimized using various parameters, finding the transport agent density as a primary factor, which depends strongly on the position of the pellet, the starting powder form, and the volume of the ampule. We demonstrated a controlled growth method by manipulating the convection and diffusion kinetics. High-quality crystals were characterized by using single-crystal X-ray diffraction, Laue diffraction, magnetic susceptibility, and Raman spectroscopy. Manipulation of magnetic properties through nonmagnetic Zn doping was shown in NiZnMo$ _{3}$ O$ _{8}$ . Our results enable the detailed investigation and manipulation of their unconventional altermagnetic and multiferroic properties. This study provides crucial insight into the controlled growth of other functional quantum materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 8 figures, 1 Table
Cryst. Growth Des. 25, 4991 (2025)
Ultrafast cooperative electronic, structural, and magnetic switching in an altermagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
Tiangao Lu, Ao Wu, Junxiang Li, Meng Zeng, Di Cheng, Chang Liu, Jiangbin Gong, Xinwei Li
Femtosecond laser control of antiferromagnetic order is a cornerstone for future memory and logic devices operating at terahertz clock rates. The advent of altermagnets – antiferromagnets with unconventional spin-group symmetries – creates new opportunities in this evolving field. Here, we demonstrate ultrafast laser-induced switching in altermagnetic $ \alpha$ -MnTe that orchestrates the concerted dynamics of charge, lattice, and spin degrees of freedom. Time-resolved reflectivity and birefringence measurements reveal that the transient melting of spin order is accompanied by pronounced structural and electronic instabilities, as evidenced by phonon nonlinearity and accelerated band gap shrinkage. Theoretical modeling highlights the key roles of robust magnetic correlations and spin-charge coupling pathways intrinsic to this altermagnet.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures
Generic continuum model formalism for moiré superlattice systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Bo Xie, Jianqi Huang, Jianpeng Liu
The moiré superlattice system provides an excellent platform for exploring various novel quantum phenomena. To theoretically tackle the diverse correlated and topological states emerging from moiré superlattices, one usually adopts an effective low-energy continuum model based on which the electron-electron effects are further considered. However, the construction of an accurate continuum model remains a challenging task, particularly for complex moiré superlattices such as twisted transition metal dichalcogenides. In this work, we develop a formalism for constructing generic continuum models that are in principle applicable for arbitrary moiré superlattices and are extrapolatable to any twist angles. Our key insight is that the microscopic electronic properties are intrinsic properties of the system, which should remain invariant across all twist angles; the lattice relaxations act as external inputs that vary with twist angles and are coupled with the electrons, and the coupling coefficients are characterized by intrinsic parameters. This partition enables a universal description of the angle variation of the continuum model using a single set of model parameters. To extract the model parameters, we design a numerical workflow based on data from first principles density functional theory calculations. We apply this framework to twisted bilayer MoTe$ _{2}$ , and obtain a single set of model parameters that accurately reproduce first-principles results, including electronic band structures, charge density distributions and Chern numbers, at three different twist angles. Furthermore, the model extrapolates robustly to smaller twist angles. Our work not only provides a more precise understanding of the microscopic properties of moiré superlattices, but also lays a foundation for future theoretical studies of low-energy electronic properties in generic moiré superlattice systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
21 pages, 6 figures
Non-Hermitian quantum geometric tensor and nonlinear electrical response
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
We demonstrate that the non-Hermitian quantum geometric tensor (QGT) governs nonlinear electrical responses in systems with a spectral line gap. The quantum metric, which is a component of the QGT and takes complex values in non-Hermitian systems, generates an intrinsic nonlinear conductivity independent of the scattering time, while the complex Berry curvature induces a wavepacket-width-dependent response. Using one-dimensional and two-dimensional non-Hermitian models, we establish a universal link between nonlinear dynamics and the QGT, thereby connecting quantum state geometry to observable transport phenomena. Crucially, our analysis indicates that the wavepacket width significantly affects non-Hermitian transport – a feature absent in Hermitian systems. This framework unifies non-Hermitian response theory by revealing how geometric degrees of freedom encode transport in open and synthetic quantum matter. Our results bridge fundamental quantum geometry with emergent functionality, offering pathways to exploit geometric effects in topological devices and engineered materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Bose-Einstein condensates in a spin-twisted harmonic trap
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-16 20:00 EDT
Huaxin He, Fengtao Pang, Xianchao Zhang, Yongping Zhang, Chunlei Qu
We investigate the ground-state phases and spin-scissors dynamics of binary Bose-Einstein condensates confined in a twisted two-dimensional harmonic trap. The ground state hosts three distinct phases-phase-separated, polarized, and phase-mixed-determined by the Rabi coupling, interaction ratio G (between inter-component and intra-component interactions), and spin-twisting which induces edge-localized polarization through position-dependent detuning. In the phase-mixed regime, the ground state is characterized by a finite spin-scissors susceptibility and can be accurately described using local density approximation. In the dynamics, the system exhibits stable periodic beating in the phase-mixed state for G<1. For G>1, its evolution progresses from beat damping (phase-separated state) to polarized relaxation (polarized state), finally reaching stable periodic beating (phase-mixed state) after a finite waiting time. The dependence of the waiting time contrasts sharply with the monotonic behavior of one-dimensional spin-dipole dynamics, revealing qualitatively distinct mechanisms governed by geometry and interactions. In summary, these results establish a unified link between ground-state properties and nonequilibrium responses in twisted spinor condensates, offering a versatile platform for exploring spin-related quantum many-body phenomena.
Quantum Gases (cond-mat.quant-gas)
Variational Gaussian Approximation in Replica Analysis of Parametric Models
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-09-16 20:00 EDT
We revisit the replica method for analyzing inference and learning in parametric models, considering situations where the data-generating distribution is unknown or analytically intractable. Instead of assuming idealized distributions to carry out quenched averages analytically, we use a variational Gaussian approximation for the replicated system in grand canonical formalism in which the data average can be deferred and replaced by empirical averages, leading to stationarity conditions that adaptively determine the parameters of the trial Hamiltonian for each dataset. This approach clarifies how fluctuations affect information extraction and connects directly with the results of mathematical statistics or learning theory such as information criteria. As a concrete application, we analyze linear regression and derive learning curves. This includes cases with real-world datasets, where exact replica calculations are not feasible.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
24 pages, 2 figures
On the magnetic contribution of itinerant electrons to neutron diffraction in the topological antiferromagnet CeAlGe
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-09-16 20:00 EDT
V. Pomjakushin, A. Podlesnyak, P. Puphal, S. Shin, J. S. White, E. Pomjakushina
We report a neutron diffraction study of the magnetic structure of CeAlGe, a candidate topological semimetal that hosts a non-collinear, multi-$ \mathbf{k}$ magnetic phase. By measuring both low- and high-momentum-transfer magnetic Bragg peaks within a single experimental setup, we refine a magnetic structure model based solely on localized Ce moments. This model, which differs from that obtained using only high-$ Q$ data, quantitatively reproduces the observed intensities, including the $ (000)$ zeroth-order magnetic satellites that are especially sensitive to subtle components of the modulation. While a contribution from itinerant electrons to the zeroth satellite cannot be definitively excluded, our analysis reveals no unambiguous evidence for such effects within experimental uncertainty. The refined magnetic structures exhibit topologically nontrivial winding patterns, derived from the fitted magnetic parameters, that support localized, particle-like spin textures with half-integer topological charges. These features provide a natural microscopic origin for the observed topological Hall effect, establishing CeAlGe as a model system where magnetism and topology are intimately linked.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Accepted in Physical Review B
Stochastic restarting with multiple restart conditions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Johannes Aspman, Daniel Mastropietro, Jakub Marecek
We consider the mean first passage time (MFPT) for a diffusive particle in a potential landscape with the extra condition that the particle is reset to its original position with some rate r. We study non-smooth and non-convex potentials and focus on the case where the restart rate depends on the space coordinate. There, we show that it is beneficial to restart at a lower rate once you are closer to your intended target.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR)
Effects of training machine-learning potentials for radiation damage simulations using different pseudopotentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
A. Fellman, J. Byggmästar, F. Granberg, F. Djurabekova, K. Nordlund
Machine learning (ML) has become a commonplace approach in the development of interatomic potentials for molecular dynamics simulations, and its use also for radiation effect modelling is increasing. In this work, we investigate the effects of training ML potentials to density functional theory data calculated with different pseudopotentials in nickel. We look in detail at the differences that appear in radiation damage simulations. The use of a “harder” pseudopotential with semicore electrons has a direct impact on the short-range interactions, which in turn has implications on the radiation damage simulations. We find that despite these differences, the average threshold displacement energy is quite similar (40-50 eV for Ni). However, we find significant differences in the cumulative damage predicted by massively overlapping cascade simulations and compare them with Rutherford Backscattering Spectroscopy/channeling experiments. We also investigate approaches to modify the repulsive pair interactions after training the potentials and discuss the feasibility of such approaches.
Materials Science (cond-mat.mtrl-sci)
Ferroelectric Fluids for Nonlinear Photonics: Evaluation of Temperature Dependence of Second-Order Susceptibilities
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
Matija Lovšin, Luka Cmok, Calum J. Gibb, Jordan Hobbs, Richard J. Mandle, Alenka Mertelj, Irena Drevenšek-Olenik, Nerea Sebastian
Ferroelectric nematic fluids are promising materials for tunable nonlinear photonics, with applications ranging from second harmonic generation to sources of entangled photons. However, the few reported values of second-order susceptibilities vary widely depending on the molecular architecture. Here, we systematically measure second-order NLO susceptibilities of five different materials that exhibit the ferroelectric nematic phase, as well as the more recently discovered layered smectic A ferroelectric phase. The materials investigated include archetypal molecular architectures as well as mixtures showing room-temperature ferroelectric phases. The measured values, which range from 0.3 to 20 pm/V, are here reasonably predicted by combining calculations of molecular-level hyperpolarizabilities and a simple nematic potential, highlighting the opportunities of modelling-assisted design for enhanced NLO ferroelectric fluids.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Descriptor and Graph-based Molecular Representations in Prediction of Copolymer Properties Using Machine Learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Elaheh Kazemi-Khasragh, Rocío Mercado, Carlos Gonzalez, Maciej Haranczyk
Copolymers are highly versatile materials with a vast range of possible chemical compositions. By using computational methods for property prediction, the design of copolymers can be accelerated, allowing for the prioritization of candidates with favorable properties. In this study, we utilized two distinct representations of molecular ensembles to predict the seven different physical polymer properties copolymers using machine learning: we used a random forest (RF) model to predict polymer properties from molecular descriptors, and a graph neural network (GNN) to predict the same properties from 2D polymer graphs under both a single- and multi-task setting. To train and evaluate the models, we constructed a data set from molecular dynamic simulations for 140 binary copolymers with varying monomer compositions and configurations. Our results demonstrate that descriptors-based RFs excel at predicting density and specific heat capacities at constant pressure (Cp) and volume (Cv) because these properties are strongly tied to specific molecular features captured by molecular descriptors. In contrast, graph representations better predict expansion coefficients ({\gamma}, {\alpha}) and bulk modulus (K), which depend more on complex structural interactions better captured by graph-based models. This study underscores the importance of choosing appropriate representations for predicting molecular properties. Our findings demonstrate how machine learning models can expedite copolymer discovery with learnable structure- property relationships, streamlining polymer design and advancing the development of high-performance materials for diverse applications.
Materials Science (cond-mat.mtrl-sci)
31 pages
Signatures of Chiral Phonons in MnPS$_3$ from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Banhi Chatterjee, Peter Kratzer
Two-dimensional (2D) materials may host circular phonons, considered as chiral if the presence of a substrate breaks mirror symmetry. In 2D transition metal dichalcogenide (TMDC) monolayers lacking inversion symmetry, phonons with a given chirality can be observed in the non-equilibrium state triggered by optical excitations using circularly polarized light. Backed by first-principles calculations, we present the antiferromagnetic semiconductor MnPS$ _3$ with a hexagonal crystal structure and bandstructure similar to TMDCs, but a larger unit cell, as a novel candidate material that may allow for excitation of circular phonons. Using DFT+U and the finite displacement method we obtain in-plane chiral phonon modes at the valley points of a monolayer MnPS$ _3$ . These modes can be classified according to the Mn or S atoms performing circular motions about their equilibrium positions. In each case, the quantized angular momentum of the phonons is calculated. Moreover, we point out ways to populate the chiral phonons selectively via optical excitation with circularly polarized light.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
10 pages, 6 figures
Orchestration of Heterogeneous Experimental Machines via ROS2 for Automated Bulk Intermetallic Synthesis
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Wei-Sheng Wang, Kensei Terashima, Yoshihiko Takano
With advances in informatics applied to materials science, predicting the physical properties of numerous materials has become increasingly feasible, creating a growing demand for their experimental validation. It has been expected that the integration of robotic systems into experimental materials science excels at efficiently performing repetitive and time-consuming tasks without the need for human intervention, thus significantly increasing throughput and reducing the risk of human error, while there have been a limited number of reports tackled the synthesis process of solid bulk material so far possibly because of the complex as well as a wide variety of processes to deal with. In this paper, we report an automated arc melting system controlled by a robot operating system2 (ROS2). Taking advantage of ROS2, we have constructed a machine that can handle multiple experimental apparatuses simultaneously with flexibility for future expansion of functions. The constructed machine is capable of not only performing repeated operation of a specific process but also dealing with multiple elements for synthesis of intermetallic compounds. The system is expected to accelerate experimental validation of data-driven materials exploration.
Materials Science (cond-mat.mtrl-sci)
13 pages, 5 figures
A shortcut through the macroscopic fluctuation theory: a generalised Fick law
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-09-16 20:00 EDT
Théotim Berlioz, Olivier Bénichou, Aurélien Grabsch
The macroscopic fluctuation theory is a powerful tool to characterise the large scale dynamical properties of diffusive systems, both in- and out-of-equilibrium. It relies on an action formalism in which, at large scales, the dynamics is fully determined by the minimum of the action. Within this formalism, the analysis of the statistical properties of a given observable reduces to solving the Euler-Lagrange equations with the appropriate boundary conditions. One must then compute the action at its minimum to deduce the cumulant generating function of the observable. This typically involves computing multiple integrals of cumbersome expressions. Recently, a simple formula has been conjectured to shortcut this last step, and compute the cumulant generating function of different observables (integrated current or position of a tracer) without the need to compute any integral. In this work, we prove this simple formula, and extend it to more general observables. We then illustrate the efficiency of this approach by applying it to compute the variance of a generalised current in the semi-infinite symmetric exclusion process and the joint properties of two occupation times in any diffusive system. In the case of the integrated current, our formula can be interpreted as a generalisation of Fick’s law to obtain all the cumulants of the current beyond the average value.
Statistical Mechanics (cond-mat.stat-mech)
28 pages
Tuning the Magnetic Anisotropy Energy of MoS$2$-supported Mn${12}$ complexes by Electric Field: A First-Principles Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Shuanglong Liu, Adam V. Bruce, Dmitry Skachkov, James N. Fry, Hai-Ping Cheng
In this work, we examine low-energy adsorption configurations of four dodecanuclear manganese single-molecule magnets [Mn$ _{12}$ O$ _{12}$ (O$ _2$ CR)$ _{16}$ (H$ _2$ O)$ _4$ ] (Mn$ _{12}$ ), where the ligand R being H, CH$ _3$ , CHCl$ _2$ or C$ _6$ H$ _5$ , on a molybdenum disulfide (MoS$ _2$ ) monolayer using force field and density functional theory calculations. The van der Waals interaction is shown to be crucial for determining the adsorption energy. Some electrons transfer from the substrate to the molecules upon surface adsorption, resulting in a reduction of the magnetic anisotropy energy of Mn$ _{12}$ . Since the lowest unoccupied molecular orbital of Mn$ _{12}$ is close to the valence band of MoS$ _2$ , a negative electric field is more effective in modulating charge transfer and energy band alignment, and thus altering the magnetic anisotropy energy, compared with a positive electric field. A significant increase in the magnetic anisotropy energy of Mn$ _{12}$ with the ligand R=CHCl$ _2$ or R=C$ _6$ H$ _5$ under a sufficiently high electric field has been predicted. Our calculations show that the molecules remain intact on the surface both before and after the electric field is applied. Finally, a two-level system formed by different adsorption configurations is evaluated, and the tunability of its energy barrier under an electric field is demonstrated. Our study sheds light on tuning the properties of single-molecule magnets using an electric field, when the molecules are supported on a surface.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Detective quantum efficiency based comparison of HRTEM and ptychography phase imaging
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-09-16 20:00 EDT
Felix Bennemann, Angus I. Kirkland, David A. Muller, Peter Nellist
High-resolution transmission electron microscopy (HRTEM) is an important method for imaging beam sensitive materials often under cryo conditions. Electron ptychography in the scanning transmission electron microscope (STEM) has been shown to reconstruct low-noise phase data at a reduced fluence for such materials. This raises the question of whether ptychography or HRTEM provides a more fluence-efficient imaging technique. Even though the transfer function is a common metric for evaluating the performance of an imaging method, it only describes the signal transfer with respect to spatial frequency, irrespective of the noise transfer. It can also not well defined for methods, such as ptychography, that use an algorithm to form the final image. Here we apply the concept of detective quantum efficiency (DQE) to electron microscopy as a fluence independent and sample independent measure of technique performance. We find that, for a weak-phase object, ptychography can never reach the efficiency of a perfect Zernike phase imaging microscope but that ptychography is more robust to partial coherence.
Materials Science (cond-mat.mtrl-sci)
Radio-frequency charge detection on graphene electron-hole double quantum dots
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Katrin Hecker, Samuel Möller, Hubert Dulisch, Şiyar Duman, Leon Stecher, Lucca Valerius, Tobias Deußen, Saketh Ravuri, Kenji Watanabe, Takashi Taniguchi, Florian Libisch, Christian Volk, Christoph Stampfer
High-fidelity detection of charge transitions in quantum dots (QDs) is a key ingredient in solid state quantum computation. We demonstrate high-bandwidth radio-frequency charge detection in bilayer graphene quantum dots (QDs) using a capacitively coupled quantum point contact (QPC). The device design suppresses screening effects and enables sensitive QPC-based charge readout. The QPC is arranged to maximize the readout contrast between two neighboring, coupled electron and hole QDs. We apply the readout scheme to a single-particle electron-hole double QD and demonstrate time-resolved detection of charge states as well as magnetic field dependent tunneling rates. This promises a high-fidelity readout scheme for individual spin and valley states, which is important for the operation of spin, valley or spin-valley qubits in bilayer graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Manuscript: 8 pages, 5 figures; Supplementary Material: 3 pages, 2 figures
Predicting Structural Relaxation in Supercooled Small Molecules via Molecular Dynamics Simulations and Microscopic Theory
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-09-16 20:00 EDT
Anh D. Phan, Ngo T. Que, Nguyen T. T. Duyen
Understanding and predicting the glassy dynamics of small organic molecules is critical for applications ranging from pharmaceuticals to energy and food preservation. In this work, we present a theoretical framework that combines molecular dynamics simulations and Elastically Collective Nonlinear Langevin Equation (ECNLE) theory to predict the structural relaxation behavior of small organic glass-formers. By using propanol, glucose, fructose, and trehalose as model systems, we estimate the glass transition temperature (Tg) from stepwise cooling simulations and volume-temperature analysis. These computed Tg values are then inserted into the ECNLE theory to calculate temperature-dependent relaxation times and diffusion coefficients. Numerical results agree well with experimental data in prior works. This approach provides a predictive and experimentally-independent route for characterizing glassy dynamics in molecular materials.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
10 pages, 6 figures, accepted for publication in Chemical Physics
Mutual synchronization of two asymmetric-nano-constriction-based spin-Hall nano-oscillators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
Roman V. Ovcharov, Roman S. Khymyn, Akash Kumar, Johan Åkerman
We propose an asymmetric-nanoconstriction (ANC) design of spin-Hall nano-oscillators (SHNOs) and investigate mutual synchronization of a pair of such devices using micromagnetic simulations. The ANC geometry enables strong dipolar coupling at sub-50 nm separations while preserving independent current bias for each oscillator. We first characterize the auto-oscillation of a single ANC-SHNO, revealing a broad frequency tuning range and a field-controlled crossover between negative and positive nonlinearities. We then demonstrate that two such oscillators can mutually synchronize solely via dipolar stray fields, without electrical or spin-wave coupling. Depending on the bias conditions, the coupled pair exhibits robust in-phase (0°) or out-of-phase (180°) locking. Notably, we find a bias-dependent amplitude correlation: when the oscillators sustain comparable amplitudes, both in-phase and out-of-phase synchronization are accessible, whereas amplitude imbalance drives the system into an out-of-phase state accompanied by suppression of the weaker oscillator. By combining strong conservative coupling with independent frequency and gain control, the ANC-SHNO platform provides a scalable route toward phased oscillator arrays, neuromorphic computing architectures, and experimental exploration of non-Hermitian spintronic dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 5 figures
Many-body skyrmion interactions in helimagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-09-16 20:00 EDT
N. P. Vizarim, J. C. Bellizotti Souza, Raí M. Menezes, Clécio C. de Souza Silva, P. A. Venegas, M. V. Milošević
Many-body interactions strongly influence the structure, stability, and dynamics of condensed-matter systems, from atomic lattices to interacting quasi-particles such as superconducting vortices. Here, we investigate theoretically the pairwise and many-body interaction terms among skyrmions in helimagnets, considering both the ferromagnetic and conical spin backgrounds. Using micromagnetic simulations, we separate the exchange, Dzyaloshinskii-Moriya, and Zeeman contributions to the skyrmion-skyrmion pair potential, and show that the binding energy of skyrmions within the conical phase depends strongly on the film thickness. For small skyrmion clusters in the conical phase, three-body interactions make a substantial contribution to the cohesive energy, comparable to that of pairwise terms, while four-body terms become relevant only at small magnetic fields. As the system approaches the ferromagnetic phase, these higher-order contributions vanish, and the interactions become essentially pairwise. Our results indicate that realistic models of skyrmion interactions in helimagnets in the conical phase must incorporate many-body terms to accurately capture the behavior of skyrmion crystals and guide strategies for controlling skyrmion phases and dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 9 figures
From hidden order to skyrmions: Quantum Hall states in an extended Hofstadter-Fermi-Hubbard model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-09-16 20:00 EDT
Fabian J. Pauw, Ulrich Schollwöck, Nathan Goldman, Sebastian Paeckel, Felix A. Palm
The interplay between topology and strong interactions gives rise to a variety of exotic quantum phases, including fractional quantum Hall (FQH) states and their lattice analogs - fractional Chern insulators (FCIs). Such topologically ordered states host fractionalized excitations, which for spinful systems are often accompanied by ferromagnetism and skyrmions. Here, we study a Hofstadter-Hubbard model of spinful fermions on a square lattice, extended by nearest-neighbor interactions. Using large-scale density matrix renormalization group (DMRG) simulations, we demonstrate the emergence of a spin-polarized $ \frac{1}{3}$ -Laughlin-like FCI phase, characterized by a quantized many-body Chern number, a finite charge gap, and hidden off-diagonal long-range order. We further investigate the quantum Hall ferromagnet at $ \nu=1$ and its skyrmionic excitations upon doping. In particular, we find that nearest-neighbor repulsion is sufficient to stabilize both particle- and hole-skyrmions in the ground state around $ \nu=1$ , whereas we do not find such textures around $ \nu=\frac{1}{3}$ . The diagnostic toolbox presented in this work, based on local densities, correlation functions, and spin-resolved observables, is directly applicable in quantum gas microscopy experiments. Our results open new pathways for experimental exploration of FCIs with spin textures in both ultracold atom and electronic systems.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
15 pages, 15 figures
Spin-polarization and diode effect in thermoelectric current through altermagnet-based superconductor heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-09-16 20:00 EDT
Debika Debnath, Arijit Saha, Paramita Dutta
The recent advent of a new class of magnetic material named as altermagnet (AM), characterized by a combination of momentum-dependent spin-splitting with zero net magnetization, has opened up promising prospects for spintronic applications. We theoretically explore how the altermagnetic spin-splitting affects the thermoelectric quasiparticle current in AM-based superconducting heterostructures. Our setup comprises of a bilayer system where a $ d$ -wave AM is proximity coupled to an ordinary $ s$ -wave superconductor (SC). We calculate the thermoelectric current carried by the quasiparticles applying a finite thermal bias accross the junction. The behavior of the thermoelectric current with the system’s base temperature and chemical potential is very similar to that in traditional SC heterostructures. Remarkably, the dissipative thermoelectric current found in the AM junction is spin-split and thus generates finite spin-polarization in the AM-based junction, which can approach $ 100%$ spin-polarization in the strong altermagnetic phase. We further investigate the thermoelectric current in AM-based Josephson junction (JJ) and illustrate how to achieve the diode effect in this AM-based JJ. The efficiency of our proposed thermoelectric diode reaches upto $ \sim 80%$ and changes its sign depending on the strength of the AM, enhancing the potential for spin-calotronics applications.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
16 pages, 12 figures and comments are welcome