CMP Journal 2025-08-19
Statistics
Nature Materials: 1
Nature Nanotechnology: 1
Nature Physics: 2
Physical Review Letters: 2
Physical Review X: 2
arXiv: 86
Nature Materials
Signatures of magnetism in zigzag graphene nanoribbons embedded in a hexagonal boron nitride lattice
Original Paper | Electronic properties and devices | 2025-08-18 20:00 EDT
Chengxin Jiang, Hui Shan Wang, Chenxi Liu, Chen Chen, Lingxiu Chen, Xiujun Wang, Yibo Wang, Ziqiang Kong, Yuhan Feng, Yixin Liu, Yu Feng, Yu Zhang, Zhipeng Wei, Maosen Guo, Aomei Tong, Gang Mu, Yumeng Yang, Kenji Watanabe, Takashi Taniguchi, Wangzhou Shi, Haomin Wang
Zigzag edges of graphene are predicted to host magnetic electronic states, critical for spintronics, but an experimental confirmation of these magnetic conduction channels remains elusive. Here we report the signatures of magnetism in zigzag graphene nanoribbons (zGNRs) embedded in hexagonal boron nitride. Hexagonal boron nitride provides crucial edge stabilization, enabling the direct probing of this intrinsic magnetism. Scanning nitrogen-vacancy-centre microscopy initially confirmed magnetism in zGNR. Subsequently, an 9-nm-wide zGNR transistor was fabricated with a sub-50-nm channel length. Magnetotransport measurements at 4 K revealed distinct Fabry-Pérot-like interference patterns, indicating coherent transport. A large, anisotropic magnetoresistance (175 Ω, ~1.3%) was observed, persisting well above room temperature. These findings strongly corroborate the existence of robust magnetic ordering in the zGNR edge state. This hexagonal-boron-nitride-embedded zGNR system offers an effective platform for future graphene-based spintronic devices.
Electronic properties and devices, Magnetic properties and materials
Nature Nanotechnology
An energy metabolism-engaged nanomedicine maintains mitochondrial homeostasis to alleviate cellular ageing
Original Paper | Drug delivery | 2025-08-18 20:00 EDT
Liyuan Chen, Yijie Fan, Nan Jiang, Xiaoshuai Huang, Min Yu, He Zhang, Zhengren Xu, Danqing He, Yu Wang, Chengye Ding, Xiaolan Wu, Chang Li, Shiying Zhang, Hangbo Liu, Xinmeng Shi, Fanghui Zhang, Ting Zhang, Dan Luo, Cunyu Wang, Yan Liu
Energy restriction is closely related to cellular senescence and species longevity. Here, based on the structure and function of ATP synthase, a key enzyme for energy generation, we develop energy metabolism-engaged nanomedicines (EM-eNMs) to rejuvenate aged stromal/stem cells, and help to prevent skeletal ageing. We show that EM-eNMs infiltrate the mitochondria of aged bone marrow mesenchymal stromal/stem cells (BMMSCs), driving mitochondrial fission, mitophagy, glycolysis and maintaining BMMSC stemness and multifunction. The EM-eNMs directly bind to the ATP synthase and promote mitophagy through induction of the dynamin-related protein 1 (DRP1) gene. Remarkably, EM-eNMs selectively target bone tissues through systemic delivery and significantly reverse osteoporotic bone loss in aged mice by enhancing mitochondrial fission and mitophagy, while simultaneously restoring the stemness and osteogenic potential of aged BMMSCs in situ. Taken together, our findings highlight the potential of the EM-eNMs as a targeted therapy to alleviate cellular senescence and age-related diseases.
Drug delivery, Nanoparticles, Nanostructures, Tissue engineering and regenerative medicine
Nature Physics
Coherent control of magnon-polaritons using an exceptional point
Original Paper | Electronic and spintronic devices | 2025-08-18 20:00 EDT
N. J. Lambert, J. J. Longdell, H. G. L. Schwefel, A. Schumer, S. Rotter
In a non-Hermitian system, the amplitude of resonant oscillations can either grow or decay in time, corresponding to a mode with either gain or loss. When two coupled modes have a specific gain-loss imbalance, an exceptional point emerges at which both eigenfrequencies and eigenmodes of the system coalesce. Exceptional points have qualitative effects on the dynamics of systems due to their topological properties, and have been used to control systems including optical microcavities, the lasing of a parity-time-symmetric waveguide and terahertz pulse generation. A challenging open problem is the fully deterministic and direct manipulation of the systems’ loss and gain on timescales relevant to the coherent control of excitations. Here we demonstrate the rapid manipulation of the complex frequency of magnon-polaritons on durations much shorter than their decay rate, allowing us to exploit non-Hermitian physics for coherent control. By dynamically encircling an exceptional point, we demonstrate population transfer between coupled magnon-polariton modes. We then drive the system directly through an exceptional point, and demonstrate that this allows the coupled system to be prepared in an equal superposition of eigenmodes. These findings establish a highly controllable hybrid platform for exploring the rich dynamical properties of non-Hermitian systems.
Electronic and spintronic devices, Quantum information
Image-guided treatment of mouse tumours with radioactive ion beams
Original Paper | Applied physics | 2025-08-18 20:00 EDT
Daria Boscolo, Giulio Lovatti, Olga Sokol, Tamara Vitacchio, Martina Moglioni, Francesco Evangelista, Emma Haettner, Walter Tinganelli, Christian Graeff, Uli Weber, Christoph Schuy, Munetaka Nitta, Daria Kostyleva, Sivaji Purushothaman, Peter G. Thirolf, Andreas Bückner, Jonathan Bortfeldt, Christoph Scheidenberger, Katia Parodi, Marco Durante
Charged particle therapy with protons or heavier ions is one of the most effective radiotherapy techniques, but uncertainties in the beam range can limit its efficacy. Radioactive ion beams are ideal for image-guided particle therapy because isotopes that undergo β+ decay can be visualized with positron emission tomography. This allows spatial localization of the particle distribution in vivo, which can be correlated with the expected dose deposition for online beam range verification. Here we report the successful treatment of a mouse osteosarcoma using a radioactive 11C-ion beam. The tumour was located in the neck, close to the spinal cord, where deviations of even a few millimetres in the beam range could lead to unintended dose deposition in the spine and radiation-induced myelopathy, an injury to the spinal cord. We achieved complete tumour control with the highest dose of 20 Gy while avoiding paralysis. Low-grade neurological side effects were correlated to the activity measured by positron emission tomography in the spine. The biological washout of the activity from the tumour volume was dependent on the dose, indicating a potential component of vascular damage at high doses. This experiment marks a step towards future clinical applications of radioactive ion beams.
Applied physics, Biological physics, Computational biophysics, Experimental nuclear physics, Imaging techniques
Physical Review Letters
Emergent Self-Propulsion of Skyrmionic Matter in Synthetic Antiferromagnets
Research article | Nonequilibrium statistical mechanics | 2025-08-18 06:00 EDT
Clécio C. de Souza Silva, Matheus V. Correia, and J. C. Piña Velásquez
Pairs of skyrmions–tiny whirlpools that emerge in some magnetic materials–might be able to self-propel, a behavior reminiscent of that of active-matter systems such as motile bacteria.
Phys. Rev. Lett. 135, 086701 (2025)
Nonequilibrium statistical mechanics, Skyrmions, Spin dynamics, Topological phases of matter, Active Brownian particles, Living matter & active matter, Synthetic antiferromagnetic multilayers
Optimal Closed-Loop Control of Active Particles and a Minimal Information Engine
Research article | Fluctuations & noise | 2025-08-18 06:00 EDT
Rosalba Garcia-Millan, Janik Schüttler, Michael E. Cates, and Sarah A. M. Loos
We study the elementary problem of moving an active particle by a trap with minimum work input. We show analytically that (open-loop) optimal protocols are not affected by activity, but work fluctuations are always increased. For closed-loop protocols, which rely on initial measurements of the self-propulsion, the average work has a minimum for a finite persistence time. Using these insights, we derive an optimal periodic active information engine, which is found to have higher precision and information efficiency when operated with a run-and-tumble particle than for an active Ornstein-Uhlenbeck particle and, we argue, than for any other type of active particle.
Phys. Rev. Lett. 135, 088301 (2025)
Fluctuations & noise, Nonequilibrium & irreversible thermodynamics, Stochastic thermodynamics, Self-propelled particles, Langevin equation
Physical Review X
Fermi Surface of ${\mathrm{RuO}}_{2}$ Measured by Quantum Oscillations
Research article | Fermi surface | 2025-08-18 06:00 EDT
Zheyu Wu, Mengmeng Long, Hanyi Chen, Shubhankar Paul, Hisakazu Matsuki, Oleksandr Zheliuk, Uli Zeitler, Gang Li, Rui Zhou, Zengwei Zhu, Dave Graf, Theodore I. Weinberger, F. Malte Grosche, Yoshiteru Maeno, and Alexander G. Eaton
Quantum oscillation measurements reveal that RuO2 lacks the bulk magnetic properties expected of an altermagnet, suggesting previous signals arose from surface effects and underscoring the need for bulk-sensitive probes in spintronics research.
Phys. Rev. X 15, 031044 (2025)
Fermi surface, High magnetic fields, Magnetic order, Density functional theory, Quantum oscillation techniques, Radio frequency techniques, Torque magnetometry
Nonreciprocal Breathing Solitons
Research article | Emergence of patterns | 2025-08-18 06:00 EDT
Jonas Veenstra, Oleksandr Gamayun, Martin Brandenbourger, Freek van Gorp, Hans Terwisscha-Dekker, Jean-Sébastien Caux, and Corentin Coulais
Breathing solitons can persist in energy-losing systems by leveraging nonreciprocal dynamics, enabling stable wave motion for efficient signaling, energy transport, and adaptive materials.
Phys. Rev. X 15, 031045 (2025)
Emergence of patterns, Mechanical metamaterials, Non-reciprocal propagation, Non-Hermitian systems, Solitons
arXiv
Quasiparticle Interference in LiFeAs: Signature of Inelastic Tunneling through Spin Fluctuations
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-19 20:00 EDT
Shun Chi, Carolina A. Marques, Walter N. Hardy, Ruixing Liang, Pinder Dosanjh, Doug A. Bonn, Sarah A. Burke, Peter Wahl
Quasi-particle interference (QPI) is a powerful tool to characterize the symmetry of the superconducting order parameter in unconventional superconductors, by mapping the spatial dependence of elastic tunneling of electrons between the tip of a scanning tunneling microscope and a sample. Here, we consider the influence of inelastic tunneling on quasi-particle interference, exemplarily for the iron-based superconductor LiFeAs. We clearly observe replica features in both experimental QPI maps and the dispersion extracted from QPI, which from comparison with theoretical model calculations can be attributed to inelastic tunneling. Analysis of the QPI dispersion shows that the inelastic mode that gives rise to these replica features exhibits a resonance between 8 and 10 meV. Comparison of the energy scale of the resonance energy estimated from QPI with inelastic neutron scattering indicates that the replica features arise from interaction with spin fluctuations.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
18 pages and 6 figures including supplementary
Andreev crystals in hybrid Josephson junction arrays
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Anders Enevold Dahl, Andrea Maiani, Max Geier, Javad Shabani, Karsten Flensberg
Andreev bound states are superpositions of electrons and holes in a metal that form by coherent reflection from a superconductor. When the length of the superconductor is comparable to the superconducting coherence length, Andreev bound states at opposite edges hybridize by quasiparticle tunneling. In a periodic array, these hybridized bound states form a band at energies below the superconducting gap. In this paper, we derive a theoretical framework for the transport properties of these Andreev crystals. We demonstrate that at high interface transparency and constant phase bias between neighboring superconductors, these bands are {\it directional}: one band consists only of right – while the other only of left-moving electronic states. This property enables the application of this device as a flux- and bias-voltage tunable filter that permits signal transmission in only one direction.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
14 pages, 7 figures
Electro-thermal Co-design of High-power Vertical \b{eta}-Ga2O3 Schottky Diodes with High-permittivity Dielectric Field-plate
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Ahsanul Mohaimeen Audri, Chung-Ping Ho, Jingjing Shi, Esmat Farzana
This work presents electrothermal co-design of vertical \b{eta}-Ga2O3 Schottky barrier diodes (SBDs) to enhance both heat dissipation and high field management in high-power applications. Here, we demonstrate device-level thermal management tailored for two vertical \b{eta}-Ga2O3 SBD structures that employed different edge termination techniques, such as field-plate and deep etch with sidewall field-plate, where the field-plate was formed with high-permittivity dielectric (BaTiO3). The localized thermal hot spots were detected at the Schottky contact edges near BaTiO3 dielectric based field-plate. However, a substantial reduction of the thermal hotspots was observed by forming the field-plate with BaTiO3 and thermally-conductive AlN insulator, where the AlN can effectively decrease Joule heating at interface and the high permittivity of BaTiO3 contributes to high field reduction. The deep etch and sidewall field-plate SBD structure further reduced accumulated heat and electric field near the critical anode edge by removing lateral depletion regions. We also analyzed thermal transport at dielectric/\b{eta}-Ga2O3 interfaces using Landauer approach that revealed significantly higher thermal boundary conductance (TBC) enabled by AlN compared to BaTiO3, attesting to the superior heat dissipation ability by BaTiO3/AlN field-plate than the BaTiO3-only configuration. Experimental investigation with vertical metal/AlN/\b{eta}-Ga2O3 diodes also extracted a high breakdown field (~11 MV/cm) of AlN, significantly exceeding the material breakdown field of \b{eta}-Ga2O3. This indicates that AlN can be an excellent choice for field-plate dielectric in vertical \b{eta}-Ga2O3 SBDs to provide both enhanced high field sustainability and improved heat dissipation in high-power applications.
Materials Science (cond-mat.mtrl-sci)
Effect of Magnetic Field on Neutral Bath Containing Charged Brownian Particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Jana Tothova, Jan Busa, Vladimir Lisy
Based on the Zwanzig-Caldeira-Legget theory generalized to systems under the influence of a static magnetic field, we obtain equations of motion for the Brownian particle (BP) and oscillators constituting the bath in which the BP is embedded. The equations are of the type of a generalized Langevin equation, which accounts for the frictional memory of the system. The BP is assumed to be charged while the bath particles are neutral. They thus do not directly respond to the external field, but their interaction with the BP leads to changes in the bath state. Using the solution of the equations found, we calculate the average bath angular momentum and show that it persists for long times when the system is assumed to reach equilibrium. This indicates a possible violation of the Bohr-van Leeuwen theorem for baths consisting of charged particles. However, this must be confirmed by a substantial generalization of the presented model when the bath particles feel the external field, which affects the memory in the dynamics of the system.
Soft Condensed Matter (cond-mat.soft)
The work presented at the 18th Czech and Slovak Conference on Magnetism, High Tatras, Slovakia, July 7-11, 2025
Collective ballistic motion explains fast aggregation in adhesive active matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Emanuel F. Teixeira, Pablo de Castro, Carine P. Beatrici, Heitor C. M. Fernandes, Leonardo G. Brunnet
Inspired by motile cells during tissue formation, we identify a mechanism by which active systems of self-aligning adhesive particles undergo ballistic aggregation via a flocking transition. This kinetic regime emerges when the cluster persistence length grows faster with cluster mass than the intercluster distance does. We also characterize and explain the emergence of distinct non-collective kinetic regimes, including long-lived transients relevant to biological systems. Our results provide a unified framework consistent with the broad range of aggregation exponents experimentally observed in cellular systems and uncover physical principles which may enable timely tissue organization
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Computational Physics (physics.comp-ph)
Ideal Fermi gas in the Dunkl formalism
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-19 20:00 EDT
Djamel Eddine Zenkhri, Abdelhakim Benkrane
This paper investigates the thermodynamic properties of an ideal Fermi gas within the framework of the Dunkl formalism, which incorporates deformation effects through reflection symmetric differential operators. The formalism is applied to reformulate the creation and annihilation operators, leading to modified expressions for the fundamental thermodynamic quantities while preserving the underlying Fermi Dirac statistics. We derived modified expressions for the main thermodynamic quantities. In both the non degenerate and degenerate limits, we examined the effects of the Dunkl parameter on the internal energy, Helmholtz free energy, entropy, and heat capacity. Furthermore, we analyzed how the Dunkl deformation influences the isothermal compressibility, the average velocity of particles, and the Pauli paramagnetism.
Quantum Gases (cond-mat.quant-gas), Mathematical Physics (math-ph)
Comprehensive Structural Characterization of Charged Polymers Involved in Moisture-Driven Direct Air Capture
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Gayathri Yogaganeshan, Rui Zhang, Raimund Fromme, Sharang Sharang, Jamie Ford, Douglas M Yates, Marlene Velazco Medel, Martin Uher, Justin Flory, Jennifer Wade, Petra Fromme
The rise in atmospheric carbon dioxide (CO2) levels has led to urgent calls for effective carbon capture methods, with direct air capture (DAC) emerging as a promising solution. This study focuses on the structural characterization of commercially available alkaline anion-exchange membrane (AEM) polymers, Fumasep FAA-3 and IRA 900, for use in low-energy, moisture-driven DAC applications. A combination of X-ray diffraction, small and wide-angle X-ray scattering (SAXS/WAXS), atomic force microscopy (AFM), focused ion beam-scanning electron microscopy (FIB-SEM), and transmission electron microscopy (TEM) were employed to explore the structural features of these materials. X-ray scattering analysis revealed molecular ordering and large-scale structural organization in both materials, while humidity-induced changes highlighted the impact of moisture on structural properties. AFM surface analysis further indicated the presence of clustering, porosity, and swelling, which were corroborated by FIB-SEM and TEM imaging. These structural insights offer a deeper understanding of the behavior of AEM-DAC materials during CO2 capture and release, emphasizing the role of moisture in these processes. This work lays the foundation for the development of more energy-efficient DAC polymers, paving the way for improved CO2 capture technologies.
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
27 pages (18 page manuscript and 9 page SI) 15 figures (6 figures in manuscript and 9 figures in SI)
Control of magnetic transition, metal-semiconductor transition, and magnetic anisotropy in noncentrosymmetric monolayer Cr$_2$Ge$_2$Se$_3$Te$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Rui-Qi Wang, Tengfei Cao, Tian-Min Lei, Xie Zhang, Yue-Wen Fang
Recent advances in two-dimensional materials have greatly expanded the family of ferromagnetic materials. The well-known 2D ferromagnets, such as CrI$ _3$ , Cr$ _2$ Ge$ _2$ Te$ _6$ , and Fe$ _3$ GeTe$ _2$ monolayers, are characterized by centrosymmetric crystal structures. In contrast, ferromagnetic ordering in 2D noncentrosymmetric materials remains an underexplored area. Here we report a Janus ferromagnet, Cr$ _2$ Ge$ _2$ Se$ _3$ Te$ _3$ with inversion symmetry breaking, through first-principles calculations. This monolayer can undergo a ferromagnetic-antiferromagnetic transformation and a metal-semiconductor transition under different strains. Additionally, the strength of magnetocrystalline anisotropy energy (MAE) can be modulated by electric field or strain. In particular, the magnetization easy axis can be altered from in-plane to out-of-plane under strain. We find that Te$ _3$ atoms play a key role in determining the MAE, where contributions are primarily from $ p_z / p_y$ and $ p_x / p_y$ orbitals. This study of Janus ferromagnetic materials has provided a promising platform for the research on the control of magnetism by strain or electric field.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
11 pages, 5 figures in main text and 5 figures in supplementary
Applied Physics Letters, 127(8), 2025
Granular focused jet
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Kazuya U. Kobayashi, Pradipto, Yoshiyuki Tagawa
We investigated the formation of granular focused jets defined as narrow upward ejections of grains triggered by impulsive forces and shaped by kinematic focusing on a concave free surface. The jets were generated from nonfluidized granular beds, in contrast to existing granular Worthington jets that originate from fluidized layers. To elucidate the jet dynamics, we performed experiments in which a test tube partially filled with dry glass beads was dropped onto a flat rigid floor, systematically varying the granular pile height$ L_{\rm G}$ , drop height $ H$ , and particle size. The resulting jet formation in granular media was driven by the same kinematic focusing mechanism responsible for jetting in liquids. By conducting parallel experiments using low-viscosity silicone oil under identical conditions, we directly compared the granular and liquid jets. At low pile heights, the granular jet velocity quantitatively agreed with the liquid jet velocity. However, at high pile heights, contrasting trends emerged. Specifically, the granular jet velocity decreased with increasing $ L_{\rm G}$ , while the liquid jet velocity increased due to cavitation. Discrete element method simulations confirmed that the velocity reduction in granular jets arose from energy dissipation via grain–grain contacts during impact force propagation. These findings highlight common mechanisms and distinctive dissipation behaviors in granular and liquid focused jets.
Soft Condensed Matter (cond-mat.soft)
Mn4Al11: A Half-Semimetal Candidate with Anomalous Electronic Behaviors
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
Shanshan Han, Rongsheng Li, Xingxing Jiang, Ming Lu, Shuxiang Xu, Jiang Zeng, Dong Wu, Nanlin Wang
Half-semimetals, characterized by their spin-polarized electronic states, hold significant promise for spintronic applications but remain scarce due to stringent electronic and magnetic criteria. Through a combination of transport measurements and optical spectroscopy, we investigated the intermetallic compound Mn4Al11, which features an exceptionally low carrier concentration and undergoes a magnetic phase transition near 68 K. Transport measurements reveal anomalies that deviate from typical metallic behavior at low temperatures. Optical spectroscopy indicates a small, nearly frequency-independent optical conductivity in the far-infrared region, with spectral weight decreasing as the temperature drops from 300 K to 50 K. These behaviors suggest a temperaturedependent carrier density and significant scattering of charge carriers. Combining experimental findings with calculated electronic band structures, we propose that Mn4Al11 is a novel half-semimetal candidate exhibiting a ferrimagnetic ground state.
Strongly Correlated Electrons (cond-mat.str-el)
Colloidal hydrodynamic interactions in viscoelastic fluid
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Dae Yeon Kim, Sachit G. Nagella, Saksham Malik, Nayeon Park, Jaewook Nam, Eric S.G. Shaqfeh, Sho C. Takatori
The motion of suspended colloidal particles generates fluid disturbances in the surrounding medium that create interparticle interactions. While such colloidal hydrodynamic interactions (HIs) have been extensively studied in viscous Newtonian media, comprehensive understanding of HIs in viscoelastic fluids is lacking. We develop a framework to quantify HIs in viscoelastic fluids with high spatiotemporal precision by trapping colloids and inducing translation-rotation hydrodynamic coupling. Using solutions of wormlike micelles (WLMs) as a case study, we discover that HIs are strongly time-dependent and depend on the structural memory generated in the viscoelastic fluid, in contrast to “instantaneous” HIs in viscous Newtonian fluids. We directly measure time-dependent HIs between a stationary probe and a driven particle during transient start-up, developing on the WLM relaxation timescale. Following the sudden cessation of the driven particle, we observe an intriguing flow reversal in the opposing direction, lasting for a time about ten times larger than the WLM relaxation time. We corroborate our observations with analytical microhydrodynamic theory, direct numerical solutions of a continuum model, and particle-based Stokesian dynamics simulations. We find that the structural recovery of the WLMs from a nonlinear strain can generate anisotropic and heterogeneous stresses that produce flow reversals and hydrodynamic attraction among colloids. Measured heterogeneities indicate a breakdown of standard continuum models for constitutive relations when the size of colloids is comparable to the length scales of the polymeric constituents and their entanglement lengths.
Soft Condensed Matter (cond-mat.soft)
22 pages, 7 figures. Supplementary Information and videos available as ancillary files
Stable crack propagation in dislocation-engineered oxide visualized by double cleavage drilled compression test
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Oliver Preuß, Zhangtao Li, Enrico Bruder, Philippe Carrez, Yinan Cui, Jürgen Rödel, Xufei Fang
Understanding crack tip - dislocation interaction is critical for improving the fracture resistance of semi-brittle materials like room-temperature plastically deformable ceramics. Here, we use a modified double cleavage drilled compression (DCDC) specimen geometry, which facilitates stable crack propagation, to achieve in situ observation of crack tip - dislocation interaction. MgO specimens, furnished with dislocation-rich barriers, were employed to study how dislocations influence crack propagation. Crack progression was clearly observed to decelerate within dislocation-rich regions, slowing to 15% of its velocity as compared to the pristine crystal. Upon exiting these regions, cracks reaccelerated until reaching the next dislocation-rich barrier. Coupled phase field and crystal plasticity modeling replicates the experimental observations and provides mechanistic insight into crack tip - dislocation interactions. The aligned experiment and simulation results underscore the robustness of the technique and its potential to inform the design of more fracture-resistant ceramics via dislocations.
Materials Science (cond-mat.mtrl-sci)
Accelerating Amorphous Alloy Discovery: Data-Driven Property Prediction via General-Purpose Machine Learning Interatomic Potential
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Xuhe Gong, Hengbo Zhao, Xiao Fu, Jingchen Lian, Qifan Yang, Ran Li, Ruijuan Xiao, Tao Zhang, Hong Li
While traditional trial-and-error methods for designing amorphous alloys are costly and inefficient, machine learning approaches based solely on composition lack critical atomic structural information. Machine learning interatomic potentials, trained on data from first-principles calculations, offer a powerful alternative by efficiently approximating the complex three-dimensional potential energy surface with near-DFT accuracy. In this work, we develop a general-purpose machine learning interatomic potential for amorphous alloys by using a dataset comprising 20400 configurations across representative binary and ternary amorphous alloys systems. The model demonstrates excellent predictive performance on an independent test set, with a mean absolute error of 5.06 meV/atom for energy and 128.51 meV/Å for forces. Through extensive validation, the model is shown to reliably capture the trends in macroscopic property variations such as density, Young’s modulus and glass transition temperature across both the original training systems and the compositionally modified systems derived from them. It can be directly applied to composition-property mapping of amorphous alloys. Furthermore, the developed interatomic potential enables access to the atomic structures of amorphous alloys, allowing for microscopic analysis and interpretation of experimental results, particularly those deviating from empirical this http URL work breaks the long-standing computational bottleneck in amorphous alloys research by developing the first general-purpose machine learning interatomic potential for amorphous alloy systems. The resulting framework provides a robust foundation for data-driven design and high-throughput composition screening in a field previously constrained by traditional simulation limitations.
Materials Science (cond-mat.mtrl-sci)
Off-Diagonal dipolar interactions in the mixed Ising–XY magnet $LiHo_{x}Er_{1-x}F_4$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
Tomer Dollberg, Moshe Schechter
We theoretically investigate the influence of off-diagonal dipolar interactions in the mixed-anisotropy magnet $ LiHo_{x}Er_{1-x}F_4$ . Motivated by experimental observations showing an unexpectedly rapid suppression of the ferromagnetic transition temperature $ T_c$ upon substitution of Ho by Er ions, we use Monte Carlo simulations incorporating off-diagonal dipolar terms to elucidate the underlying physical mechanism. Our results reveal that, unlike in the diluted magnet $ LiHo_{x}Y_{1-x}F_4$ , where dilution weakens the effect of these interactions, substitution by planar Er ions amplifies it. This leads to a pronounced reduction of $ T_c$ , closely matching experimental data, thereby resolving discrepancies with mean-field predictions. The findings underscore the essential role of off-diagonal dipolar interactions in determining the magnetic properties of mixed-anisotropy dipolar systems.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 5 figures
Domain Wall-mediated Interfacial Ferroelectric Switching
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Hao-Wen Xu, Wen-Cheng Fan, Jun-Ding Zheng, Cheng-Shi Yao, Ni Zhong, Wen-Yi Tong, Chun-Gang Duan
Interfacial ferroelectricity offers a promising platform for ultrafast, low-power memory devices. While previous studies have attributed polarization switching to full-layer sliding, the symmetry constraints pose fundamental limitations. By integrating first-principles calculations, machine learning methods, and experimental validations, we show that domain walls within in-plane polarization break C3 symmetry, enabling polarization switching under out-of-plane electric fields. Local polarization vectors deviate to response to the field, leading to local reconstruction, and ultimately drives the migration of domain walls. This mechanism bears clear resemblance to that in traditional ferroelectrics. Notably, different domain wall types result in distinct switching behaviors, which play a crucial role in determining the reversibility of polarization switching. We then propose strategies beyond ideal conditions to achieve non-volatile ferroelectric switching, successfully realized by our experiments. These insights clarify the microscopic switching mechanism in hexagonal interfacial ferroelectrics, providing a basis for future nanoelectronics applications.
Materials Science (cond-mat.mtrl-sci)
Voltage-tunable field-free Josephson diode
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Sjoerd Telkamp, Junting Zhao, Saulius Vaitiekėnas
We report a gate-tunable Josephson diode effect in hybrid nanowire junctions consisting of a spin-orbit-coupled semiconductor core coated with epitaxial ferromagnetic insulator and superconductor shells. The wires display a hysteretic superconducting window as a function of axial magnetic field. In the superconducting regime, the devices exhibit nonreciprocal supercurrent transport, with the diode efficiency showing a strong dependence on back-gate voltage. The effect persists in a remanent magnetization state following a controlled demagnetization procedure, establishing zero-field operation. These findings demonstrate a voltage-controlled Josephson diode in a single junction and suggest a route toward probing intrinsically broken inversion and time-reversal symmetries in hybrid materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 4+5 figures
Generalized invariants meet constitutive neural networks: A novel framework for hyperelastic materials
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Denisa Martonová, Alain Goriely, Ellen Kuhl
The major challenge in determining a hyperelastic model for a given material is the choice of invariants and the selection how the strain energy function depends functionally on these invariants. Here we introduce a new data-driven framework that simultaneously discovers appropriate invariants and constitutive models for isotropic incompressible hyperelastic materials. Our approach identifies both the most suitable invariants in a class of generalized invariants and the corresponding strain energy function directly from experimental observations. Unlike previous methods that rely on fixed invariant choices or sequential fitting procedures, our method integrates the discovery process into a single neural network architecture. By looking at a continuous family of possible invariants, the model can flexibly adapt to different material behaviors. We demonstrate the effectiveness of this approach using popular benchmark datasets for rubber and brain tissue. For rubber, the method recovers a stretch-dominated formulation consistent with classical models. For brain tissue, it identifies a formulation sensitive to small stretches, capturing the nonlinear shear response characteristic of soft biological matter. Compared to traditional and neural-network-based models, our framework provides improved predictive accuracy and interpretability across a wide range of deformation states. This unified strategy offers a robust tool for automated and physically meaningful model discovery in hyperelasticity.
Soft Condensed Matter (cond-mat.soft), Artificial Intelligence (cs.AI)
Scaling Behaviors in Active Model B+ via the Functional Renormalization Group
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
Gergely Fejős, Zsolt Szép, Naoki Yamamoto
We study the scaling behaviors of the Active Model B+ using the functional renormalization group (FRG) approach, based on the nonequilibrium effective action formulated via the Martin-Siggia-Rose path-integral formalism. We derive the $ \beta$ functions for all couplings of the system in generic $ d$ dimensions, revealing regulator independence in various contributions to the RG flow at specific values for $ d$ . After identifying specific regions of the parameter space that define submodels closed under RG transformations, we determine all fixed points of potential physical relevance. We confirm the existence of a bicritical fixed point, which was conjectured within the perturbative momentum-shell RG method for being responsible for the transition from bulk phase separation to microphase separation in active systems. We argue that, within the FRG approach, global flows significantly differ from those obtained in its perturbative counterpart.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), High Energy Physics - Theory (hep-th)
16 pages, 4 figures
High-root topological edge-state bands
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
R. G. Dias, L. Madail, A. M. Marques
This paper presents a complex band analysis of one-dimensional (1D) square and high-root topological insulators (HRTIs). We show that edge-state bands of HRTIs are sliced sections of impurity bands of a uniform tight-binding chain. A simplified topological characterization of HRTIs with generalized boundary conditions is carried out based on the existence of edge-state bands in the infinite HRTI and the restrictions imposed by the boundary conditions. Edge states in finite or semi-infinite 1D HRTIs are shown to be a subset of evanescent states of the infinite system and mapped onto impurity states of the uniform chain with effective energy-dependent edge potentials. The latter result allows the determination of the edge state levels without needing the diagonalization of real space or bulk Hamiltonians.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 7 figures
Phys. Rev. B 112, 075125 (2025)
Dynamic-Kinetic Duality of Particulate and Multiphase Systems
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
The evolution of particulate and multiphase systems can transition from dynamic regimes, governed by classical transport equations with well-defined damping coefficients, to anomalously slow relaxation described by rate equations when the system is critically close to equilibrium. This regime crossover has been both theoretically predicted and experimentally observed in diverse multiphase systems relevant to numerous technological applications, including nanoparticle adhesion at interfaces and liquid imbibition under microscale confinement, and it is attributed to the presence of small nanoscale features of physical or chemical nature at liquid-solid interfaces. This article presents a theoretical framework to more accurately predict and control, advancing or delaying, the dynamic-to-kinetic regime crossover, and highlights strategies for harnessing this phenomenon to enhance or suppress different transport processes in confined multiphase systems.
Soft Condensed Matter (cond-mat.soft)
21 pages, 5 figures
Diode Effect for Skyrmions Interacting with Linear Protrusion Defects
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
J. C. Bellizotti Souza, C. J. O. Reichhardt, C. Reichhardt, N. P. Vizarim, P. A. Venegas
We simulate collectively interacting skyrmions in a channel with periodic asymmetry, and find a strong diode effect for the skyrmion flow. There is also an asymmetry in the skyrmion annihilation rate for currents applied along the hard or easy substrate asymmetry direction, with a higher annihilation rate for hard direction currents. We map out the diode efficiency as a function of magnetic field and substrate asymmetry angle. We also show that the Magnus force impacts the diode motion and annihilation rate asymmetry by forcing skyrmions into corners of the protrusion geometry.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 8 figures
Strong overlap of deterministic and stochastic dynamics in a super-diffusive regime
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
Muhammad Tayyab, Jahanzeb Tariq
We consider deterministic dynamics, known as the slicer map (SM), which exhibits normal and anomalous diffusion by varying a single parameter. The statistics of the position moments and the low-order position autocorrelation function (PACF) of the SM closely overlap with those of a stochastic process called the Lévy-Lorentz gas (LLg), particularly in the normal and strongly superdiffusive anomalous regimes. However, matching low-order statistics alone cannot fully characterize the microscopic dynamics or distinguish underlying process classes. To demonstrate how these dynamics strongly overlap, we focus on the scaling of higher-order PACF, which provides a more detailed characterization. In this paper, we analytically derive the generalized PACF of the SM and explore its scaling forms under different temporal relationships. Specifically, we derive several scalings of the 3-point PACF by analyzing intriguing relations between three times. We compare these scalings with the power-law tails of the numerically estimated 3-point PACF of the LLg. This comparison provides a detailed description of the correlation scalings of the SM, demonstrating that the SM shares key features with the LLg. Our findings establish the SM as a deterministic analog of the LLg, enabling efficient prediction of multi-time position correlations in superdiffusive systems.
Statistical Mechanics (cond-mat.stat-mech)
22 pages, 5 figures
Quantized nonlinear kink movement through topological boundary state instabilities
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Markus Bestler, Oded Zilberberg
Thouless pumping is a paradigmatic example of topologically protected, directed transport in linear systems. Recent extensions to nonlinear pumps often overlook the need to reassess the conventional framework of linear topology. In this work, we study a nonlinear dimer-chain model that exhibits quantized transport of kinks under a periodic modulation of a pumping parameter. Crucially, linear excitations in the system map to a Rice-Mele model and display topological boundary modes localized at these kinks. Using methods from nonlinear dynamics, we show that instabilities in these boundary modes are the driving mechanism behind the observed kink motion. While the transport resembles that of a linear Thouless pump, it cannot be fully captured by conventional topological indices. Instead, the behavior is more akin to a topological ratchet: robust, directional, and reproducible, yet fundamentally nonlinear. Furthermore, by introducing multiple pumping parameters, we demonstrate fine control over multiple kink trajectories, as well as soliton motion, suggesting applications in information transport. Our results unify concepts from linear topology and nonlinear dynamics to establish a framework for quantized transport in nonlinear media.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Pattern Formation and Solitons (nlin.PS), Optics (physics.optics), Quantum Physics (quant-ph)
11 pages, 7 figures; comments are welcome
Microscopic model of the operation of the Single-chalcogenide X-point Memory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
P. Fantini, A. Ghetti, E. Varesi, A. Pirovano, F. Pellizzer, D. Baratella, C. Ribaldone, S. Caravati, D. Campi, M. Bernasconi, R. Bez
Ovonic threshold switching is the key process for several applications of chalcogenide alloys including phase change memories and selector elements in cross-points arrays. Very recently, it has been shown that the threshold switching voltage VT depends on the polarity of the applied field. This feature has been already exploited in the realization of the Single Chalcogenide X-point Memory (SXM) in which a single film of a chalcogenide alloy can serve as both a memory and selector unit. In this work, we provide a microscopic understanding of the polarity-dependent VT by leveraging electrical and physical measurements, numerical simulations based on technology computer aided design (TCAD) and electronic structure calculations based on density functional theory (DFT). We developed a Graded Band Gap (GBG) model in which an inhomogeneous distribution of localized electronic states in the gap is established by the opposite effect of a strong electric field at the cathode and a high density of electrons in the conduction band at the anode. The model is suitable to reproduce several features of the programming window, including its dependence on temperature, thickness and composition of the chalcogenide alloy. The microscopic understanding that we gained on the SXM operation lays the foundation for important improvements in the memory design and in the selection of better performing alloys for applications in enabling memory technologies.
Materials Science (cond-mat.mtrl-sci)
17 pages + 6 pages of Supplementary Information
Dual-species atomic absorption image reconstruction using deep neural networks
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-19 20:00 EDT
Optical imaging plays an instrumental role in understanding the behavior of trapped neutral atoms. In this work, we describe a deep learning-based online image completion protocol that reduces interference fringes in optical absorption signals for a dual-species atomic system. Regardless of the distinct nature of the task for two different atomic species, 6Li and 23Na, the method displays a robust solution for suppressing fringes. To incorporate this into daily operations, a transfer learning scheme is required that incrementally updates the previously learned parameters. We outline an online image completion method that efficiently adapts to drifting experimental conditions. Our method can be easily integrated into lab settings, where transfer learning can accelerate image analysis.
Quantum Gases (cond-mat.quant-gas)
Universal Thermodynamics of Dunkl-Deformed Bose Gases: From Power-Law Traps to Physical Bounds
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-19 20:00 EDT
M. Medani, M. Benarous, A. Hocine, F. Merabtine
We study an ideal Bose gas confined by a $ D$ -dimensional power-law potential within the framework of the Dunkl formalism. By analyzing the combined effects of spatial dimensionality and trap geometry, we derive universal expressions for the thermodynamic quantities, which depend solely on a single parameter. This reduction reveals the existence of universality classes that apply to any power-law potential, regardless of its specific form.
Quantum Gases (cond-mat.quant-gas)
15 pages, 5 figures
About carrier’s self-trapping and dynamical Rashba splitting in the two-dimensional hybrid perovskite (BA)$_2$(MA)$_2$Pb$3$I${10}$
New Submission | Other Condensed Matter (cond-mat.other) | 2025-08-19 20:00 EDT
W. Qi, S. Ponzoni, G. Huitric, V. Gorelov, A. Pramanik, Y. Laplace, M. Marsi, E. Papalazarou, S. F. Maehrlein, E. Deleporte, N. Mallik, A. Taleb Ibrahimi, A. Bendounan, K. Zheng, T. Pullerits, L. Perfetti
Time- and Angle-Resolved Photoelectron Spectroscopy is employed to monitor photoexcited electrons in the two-dimensional (BA)$ _2$ (MA)$ _2$ Pb$ _3$ I$ _{10}$ . ARPES intensity maps are in good agreement with ab-initio calculations of the band structure. The effective mass is $ -0.18 \pm 0.02 m_e$ and $ 0.12 \pm 0.02 m_e$ for holes and electrons, respectively. In the photoexcited state, spin-orbit splitting of the conduction band cannot be resolved. This sets the upper bound of photoinduced Rashba coupling to $ \alpha_C<2.5$ eVÅ. The correlated electron-hole plasma evolves in Wannier excitons with Bohr radius of 2.5 nm, while no sign of self-trapping in small polarons is found within the investigated time window of up to 120 ps following photoexcitation.
Other Condensed Matter (cond-mat.other)
Comparative study of magnetic exchange parameters and magnon dispersions in NiO and MnO from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Flaviano José dos Santos, Luca Binci, Guido Menichetti, Ruchika Mahajan, Nicola Marzari, Iurii Timrov
Spin-wave excitations are fundamental to understanding the behavior of magnetic materials and hold promise for future information and communication technologies. Yet, modeling these accurately in transition-metal compounds remains challenging, starting from the self-interaction errors affecting localized and partially filled $ d$ -orbitals in density-functional theory (DFT) with (semi-)local functionals. In this work, we compare three advanced first-principles approaches for computing magnetic exchange parameters and magnon dispersions in NiO and MnO, all based on a common DFT+$ U$ ground state with ab initio Hubbard $ U$ values obtained from density-functional perturbation theory. Two methods extract exchange parameters directly: one via total-energy differences using the four-state mapping ($ \Delta E$ ), and the other via the magnetic force theorem (MFT) using infinitesimal spin rotations. Magnon dispersions are then obtained from a Heisenberg Hamiltonian through linear spin-wave theory (LSWT). The third approach, time-dependent density-functional perturbation theory with $ U$ (TDDFPT+$ U$ ), yields magnon dispersions directly from the dynamical spin susceptibility, with exchange parameters fitted a posteriori, for comparison, via LSWT. Our results show that TDDFPT+$ U$ and the Heisenberg model based on $ \Delta E$ -derived parameters align well with experimental neutron scattering data, whereas the MFT-based approach shows larger discrepancies, possibly due to some inherent approximations and limitations of the particular implementation used. This study benchmarks the accuracy of state-of-the-art first-principles techniques for spin-wave modeling and contributes to advancing reliable computational tools for the study and design of magnetic materials.
Materials Science (cond-mat.mtrl-sci)
Critical Importance of Grain Boundaries to the Conductivity of Polycrystalline Molecular Crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Shujit Chandra Paul, William A. Goddard III, Michael J. Zdilla, Prabhat Prakash, Stephanie L. Wunder
Soft-solid molecular crystals consist of crystalline grains and fluid grain boundaries (GB) that enhance the grain binding and transport of Li+ ions between the grains. The total ionic conductivity consists of ion migration in both the grains and GBs. To unravel these contributions in adiponitrile (Adpn)-LiPF6 molecular crystals, the GB volume fraction was varied by changing the size of the crystals and the adiponitrile/LiPF6 molar ratio. Molecular dynamic (MD) simulations indicate that ion motion was sub-diffusive in the grains and well-diffusive in the GBs, with GBs characterized as disordered nano-confined regions of higher charge carrier concentration (1M) than in saturated LiPF6-Adpn solutions (0.04M), and ions predominantly solvated by -CN groups with few contact ion pairs. The diffusivity in the GBs is at least an order of magnitude higher than in the crystalline grains. The emergent picture is the grains as a reservoir of ions that migrate to the fast-conducting GBs.
Materials Science (cond-mat.mtrl-sci)
Novel SuperLattice Plasmon Mode in a Grating of 2D Electron Strips
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
V. M. Muravev, K. R. Dzhikirba, A. A. Zabolotnykh, A. Shuvaev, M. S. Ryzhkov, D. A. Khudaiberdiev, A. S. Astrakhantseva, I. V. Kukushkin, A. Pimenov
We investigate GaAs/AlGaAs heterostructure membranes with a metasurface made up of a grating of two-dimensional electron system (2DES) strips. Experiments have revealed a strong plasma resonance in the transmission of the metasurface. We have found that a collective effect from the superlattice, along with lateral screening between the strips, leads to the emergence of a new plasmon mode in the metasurface under study. Furthermore, we develop an analytical approach that accurately describes the behavior of the discovered superlattice plasmon mode, providing new insights into the fundamental physics of plasmonic metasurface systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Bridging Molecular Simulation and Process Modeling for Predictive Multicomponent Adsorption
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
Sunghyun Yoon, Jui Tu, Li-Chiang Lin, Yongchul G. Chung
Accurate and efficient prediction of multicomponent adsorption equilibria across pressures, temperatures, and compositions remain a central challenge for designing energy-efficient adsorption-based separation processes. Traditional approaches, including model fitting and ideal adsorbed solution theory (IAST), often fail to balance accuracy, computational efficiency, and transferability under process-relevant conditions. Here, we introduce a material-to-process modeling framework that integrates macrostate probability distributions (MPDs) from flat-histogram Monte Carlo simulations with rigorous cyclic process optimization. MPDs directly capture the joint occupancy distributions of adsorbates, producing reweightable landscape that enable high-fidelity mixture adsorption equilibria without repeated simulations or model assumptions. We show that coupling this statistical mechanical foundation with process modeling delivers accurate and computationally efficient evaluations for binary and ternary gas mixture separations. This integration establishes MPD-based modeling as a generalized method for predictive multicomponent adsorption equilibria, accelerating the discovery and design of adsorbent materials for carbon capture and other separation challenges.
Statistical Mechanics (cond-mat.stat-mech), Materials Science (cond-mat.mtrl-sci)
Steering chiral active Brownian motion via stochastic position-orientation resetting
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Guiding active motion is important for targeted delivery, sensing, and search tasks. Many active systems exhibit circular swimming, ubiquitous in chemical, physical, and biological systems, that biases motion and reduces transport efficiency. We show that stochastic position-orientation resetting can overcome these limitations in two-dimensional chiral active Brownian particles by interrupting circular motion, resulting in tunable dynamics. When resets are infrequent compared to chiral rotation, the steady-state mean-squared displacement varies non-monotonically with rotational diffusion. Steady state excess kurtosis and orientation autocorrelation yields spatiotemporal state diagram comprising three states: an activity-dominated chiral state, and two resetting-dominated states with and without chirality; in contrast, the achiral counterpart supports only the resetting-dominated state. Chirality thus enriches the dynamical landscape, enabling tunable transitions between transport modes absent in achiral systems. A simple reset protocol can thus transform chiral active dynamics and offer a practical strategy for optimizing search and transport in circle swimmers.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
15 pages, 9 figures
Ultrafast Nonequilibrium Enhancement of Electron-Phonon Interaction in 2H-MoTe$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Nina Girotto Erhardt, Sotirios Fragkos, Dominique Descamps, Stéphane Petit, Michael Schüler, Dino Novko, Samuel Beaulieu
Understanding nonequilibrium electron-phonon interactions at the microscopic level and on ultrafast timescales is a central goal of modern condensed matter physics. Combining time- and angle-resolved extreme ultraviolet photoemission spectroscopy with constrained density functional perturbation theory, we demonstrate that photoexcited carrier density can serve as a tuning knob to enhance electron-phonon interactions in nonequilibrium conditions. Specifically, nonequilibrium band structure mapping and valley-resolved ultrafast population dynamics in semiconducting transition-metal dichalcogenide 2H-MoTe$ _2$ reveal band-gap renormalizations and reduced population lifetimes as photoexcited carrier densities increase. Through theoretical analysis of photoinduced electron and phonon energy and linewidth renormalizations, we attribute these transient features to nonequilibrium modifications of electron-phonon coupling matrix elements. The present study advances our understanding of microscopic coupling mechanisms enabling control over relaxation pathways in driven solids.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Optics (physics.optics)
Photocatalytic CO2 Reduction Enhanced by Synergetic Interactions among Photon Phonon and Molecule
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Photocatalytic CO2 reduction is limited by inefficient CO2 activation and poor solar spectrum utilization. Here, we discovered and revealed the vibration coupling mechanism among photons, phonons, and molecules, which remarkably enhances photocatalytic catalysis of CO2 into fuels. We designed the nitrogen-doped Cu2O-based catalyst loaded onto the quartz optical substrate. The N-doping Cu2O converts linearly geometry of adsorbed CO2 molecules, which efficiently lowers the activation barrier and facilitates CO2 dissociation. Once the Cu-based catalyst is combined with a micro-pillar quartz film, the system induces vibrational strong coupling (VSC) between the asymmetric CO2 stretching mode and surface phonon polariton resonances. These resonances arise from the photothermal conversion of incident solar photons on the micro-pillars. The resonant coupling phenomena were further verified by Fourier-transform infrared spectroscopy using Synchrotron Radiation Source (SRS), which directly confirmed the interactions between molecular vibrations and photonic-phononic modes. The synergetic functions originated from this hybrid architecture achieve a CO yield of 167.7 umol h-1 g-1 under pure water conditions, which is the highest reported yield for Cu2O-based photocatalysts with 46% enhancement over non-VSC systems. This work uncovers a novel photo-thermal mechanism. It further provides a new strategy to control bond activation in photocatalytic CO2 conversion through light-vibration-matter coupling.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Atom-surface interaction induced by quenched monopolar charge disorder
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
We study the modification to the energy level shifts of an atom induced by the quenched monopolar charge disorder inside the bulk of neighboring dielectric slabs as well as their surfaces. By assuming that the charge disorder follows Gaussian statistics with a zero mean, we find that the disorder generally results in a downward shift of the energy levels, which corresponds to an attractive force that can compete with and overcome the nonresonant Casimir-Polder force for sufficiently large atom-surface separations $ z_0$ . For an atom near a single semi-infinite slab with bulk (surface) charge disorder, the shift decays as $ z_0^{-1}$ ($ z_0^{-2}$ ). For both surface and bulk disorder, the shift is proportional to the variance of the charge disorder density. In addition, we investigate the behavior of the charge disorder-induced energy level shift for an atom confined to a vacuum gap between two coplanar and semi-infinite slabs of the same dielectric material, finding that the position of net zero disorder-induced force occurs closer to the surface of the slab with the smaller charge disorder variance.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Atomic Physics (physics.atom-ph)
16 pages, 7 figures, 5 appendices
Phase transitions driven by solute concentration, temperature, and pressure in uranium-6wt % niobium alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Yanwen Liao, Yongfeng Huang, Kun Wang, Wenjun Zhu, Wu-Xing Zhou, Yi Liao, Songlin Yao
An angular-dependent potential for the U-Nb system is developed based on an existing ADP for U and a new EAM potential for Nb through fitting flexible cross-interaction functions and alloy parameters to experimental and first-principles data, enabling accurate prediction of phase transitions (alpha to gamma driven by solute concentration; alpha-prime to gamma under temperature in U-6Nb alloy), elastic properties, defect energetics, and mixed enthalpy. The potential reliably reproduces melting points of U-Nb solid solutions and captures lattice parameter expansion of gamma U-6Nb. Notably, it correctly predicts Hugoniot relations and equations of state up to about 90 GPa and resolves the alpha-prime to gamma transition under static high pressure. Combined with atomic simulations, we reveal a twinning-coupled alpha-prime to gamma transition of U-6Nb under high pressures: {112}gamma twins form via nanosecond-scale twinning precursors generated during the transient adiabatic compressions. The static phase transition pressure is predicted to be 54.5 GPa, comparable to 67.2 GPa by first-principles calculations. Besides, our result suggests that U-6Nb single-crystal would experience a nonlinear elastic relaxation before yielding plastically at 3.1 GPa (shear stress: 0.9 GPa). The results in this work help resolve long-standing discrepancies in understanding the abnormal shear stress relaxation mechanisms under high-pressure shock loading.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
36 pages, 16 figures
Enhancement of the energy storage and electrocaloric effect performances in 0.4 BCZT 0.6 BSTSn medium entropy ceramic prepared by sol gel method
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
S. Khardazi, Z. Gargar, A. Lyubchyk, O. Zakir, D. Mezzane, M. Amjoud, A. Alimoussa, Z. Kutnjak
Based on the traditional polycrystalline ferroelectric Ba0.85Ca0.15Zr0.10Ti0.90O3, the 0.4 Ba0.85Ca0.15Zr0.10Ti0.90O3 0.6 Ba0.9Sr0.1Ti0.9Sn0.1O3 medium entropy material with good energy storage and electrocaloric effect performances is designed and synthesized by the solgel method. The structural, dielectric, energy storage and electrocaloric effect properties of the prepared sample were studied. The findings demonstrate that the 0.4 Ba0.85Ca0.15Zr0.10Ti0.90O3 0.6 Ba0.9Sr0.1Ti0.9Sn0.1O3 ceramic simultaneously has a significant recoverable energy storage density of 255.4 mJ/cm3, an efficiency of 67.9%, a large ECE temperature change of 1.36 K, and a high ECE responsivity of 0.453 this http URL under a low electric field of 30 kV/cm. Moreover, excellent temperature stability of Wrec (less than 10%) was achieved in the investigated sample 0.4BCZT 0.6BSTSn.
Materials Science (cond-mat.mtrl-sci)
Topological Dissipation as the Missing Link in Multiscale Polymer Dynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Xu-Ze Zhang, Rui Shi, Ming-Ji Fang, Zhong-Yuan Lu, Hu-Jun Qian
We identify topological dissipation – momentum transport along the polymer backbone with Ising-type exponential decay ($ \sim \exp(-\Delta n/n_\text{d})$ ) – as the missing link connecting atomistic and mesoscale dynamics. Simulations of four polymers reveal that dynamical correlation length $ n_\text{d} \approx n_\text{k}/3$ (Kuhn length $ n_\text{k}$ ), enabling a coarse-grained framework that \emph{explicitly separates} topological (intrachain) and spatial (interchain) dissipation channels without temporal memory kernels. The approach quantitatively reproduces dynamics from segmental relaxation to chain diffusion, solving the long-standing memory preservation challenge in Markovian coarse-graining. Our results establish topology-mediated dissipation as a key mechanism for polymer dynamics.
Soft Condensed Matter (cond-mat.soft)
5 pages, 5 figures
Non-Hermitian Chiral Superfluids with a Complex Interaction
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-19 20:00 EDT
Recently, the influence of dissipation on a quantum system has attracted much attention, particularly on how the non-Hermitian terms modify the energy spectrum, band topology, and phase transition point. Motivated by the recent investigation of non-Hermitian $ s$ -wave superfluidity, we study the non-Hermitian chiral $ p+ip$ superfluid (SF) with a complex-valued interaction, originating from inelastic scattering between fermions. We reformulate the non-Hermitian mean-field theory for chiral SFs and derive the gap equation in the path integral approach. By numerically solving the gap equation, we obtain the phase diagram of the non-Hermitian $ p+ip$ SF, characterized by the reentrant SF transition and dissipation-induced SF phase, as a result of the evolution of the exceptional lines. The method can be extended to higher partial-wave chiral SFs, such as $ d+id$ and $ f+if$ -wave SFs. We further consider such a chiral $ p+ip$ SF on a square lattice, to investigate the influence of dissipation on topology. We find that the non-Hermitian skin effect is absent in the specific cylinder geometry, in which the topology associated with the edge modes and Chern number is robust to dissipation. Besides, we find that the energies at the robust point nodes and line nodes are pure real. We further verify the conditions of zero winding number in (quasi-) one-dimensional systems, and prove an associated ``no-go’’ theorem, which is hopefully applied to explore the geometry dependent skin effect.
Superconductivity (cond-mat.supr-con)
18 pages, 8 figures
Chiral quantum magnets with optically and catalytically active spin ladders
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Bum Chul Park, Sung-Chul Kim, Dae Beom Lee, Young Kwang Kim, Bomin Kim, Sonny H. Rhim, Eunsoo Lee, Yongju Hong, Kwangyeol Lee, Sang Hyun Lee, Jessica Ma, Michal Sawczyk, Jun Lu, Jason Manassa, Nishkarsh Agarwal, Robert Hovden, Sung Ok Won, Min Jun Ko, Minkyu Park, Jiung Cho, Xiaoming Mao, Kai Sun, Young Keun Kim, Nicholas A. Kotov
Chiral quantum magnets with spin-states separated by a large energy gap are technologically attractive but difficult to realize. Geometrically frustrated topological states with nanoscale chirality may offer a chemical pathway to such materials. However, room temperature spin misalignment, weakness of Dzyaloshinskii-Moriya interactions, and high energy requirements for lattice distortions set high physicochemical barriers for their realization. Here, we show that layered iron oxyhydroxides (LIOX) address these challenges due to chirality transfer from surface ligands into spin-states of dimerized FeO6 octahedra with zig-zag stacking. The intercalation of chiral amino acids induces angular displacements in the antiferromagnetic spin pairs with a helical coupling of magnetic moments along the screw axis of the zig-zag chains, or helical spin-ladders. Unlike other chiral magnets, the spin states in LIOX are chemically and optically accessible, they display strong optical resonances with helicity-matching photons and enable spin-selective charge transport. The static rather than dynamic polarization of spin ladders in LIOX makes them particularly suitable for catalysis. Room-temperature spin pairing, field-tunability, environmental robustness, and synthetic simplicity make LIOX and its intercalates a uniquely practical family of quantum magnets.
Materials Science (cond-mat.mtrl-sci)
24 pages, 5 figures
Structural contribution to light-induced gap suppression in Ta$_2$NiSe$_5$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Chen Zijing, Xu Chenhang, Xie Chendi, Tang Weichen, Liu Qiaomei, Wu Dong, Xu Qing, Jiang Tao, Zhu Pengfei, Zou Xiao, Li Jun, Wang Zhiwei, Wang Nanlin, Qian Dong, Zong Alfred, Xiang Dao
An excitonic insulator is a material that hosts an exotic ground state, where an energy gap opens due to spontaneous condensation of bound electron-hole pairs. Ta$ _2$ NiSe$ _5$ is a promising candidate for this type of material, but the coexistence of a structural phase transition with the gap opening has led to a long-standing debate regarding the origin of the insulating gap. Here we employ MeV ultrafast electron diffraction to obtain quantitative insights into the atomic displacements in Ta$ _2$ NiSe$ _5$ following photoexcitation, which has been overlooked in previous time-resolved spectroscopy studies. In conjunction with first-principles calculations using the measured atomic displacements, we find that the structural change can largely account for the photoinduced reduction in the energy gap without considering excitonic effects. Our work illustrates the importance of a quantitative reconstruction of individual atomic pathways during nonequilibrium phase transitions, paving the way for a mechanistic understanding of a diverse array of phase transitions in correlated materials where lattice dynamics can play a pivotal role.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Charge-4$e$ Anyon Superconductor from Doping $\text{SU}(4)_1$ chiral spin liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
Lu Zhang, Ya-Hui Zhang, Xue-Yang Song
Previous studies have shown that $ \text{SU}(4)1$ chiral spin liquid can emerge in the SU($ 4$ ) Hubbard model on triangular lattice. A natural question then arises: What is the phase upon doping? In this work, we show the possibility that hole doping can give rise to an anyon superconductor and propose that both spinons and holons form integer quantum Hall states with opposite chiralities. Using topological field theory we demonstrate that the phase is a topological charge-$ 4e$ superconductor with chiral central charge $ c-=4$ . We further identify the deconfined excitations and anyonic excitations bound to the vortex. This unusual superconductor may be realized in moir’e bilayer and detected through quantized thermal Hall effect and spin quantum Hall effect.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
9 pages, 1 figures
CoRuTiGe: A Possible Spin Gapless Semiconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Ravinder Kumar, Tufan Roy, Baisali Ghadai, Rakesh Kumar, Sucheta Mondal, Anil Kumar, Archana Lakhani, Devendra Kumar, Masafumi Shirai, Sachin Gupta
We report experimental and theoretical investigations on the quaternary Heusler alloy CoRuTiGe, synthesized using the arc melting technique. Crystal structure analysis reveals a tetragonal structure at room temperature. Magnetization measurements as a function of temperature and magnetic field indicate ferromagnetic nature with a saturation magnetization of 0.681 mB/f.u. at 5 K. The temperature dependence of electrical resistivity shows a nearly linear decrease in the high-temperature range, indicating the spin gapless semiconductor like behavior of the material. This SGS nature is further supported by the temperature-independent carrier concentration and mobility. Hall effect analysis reveals that the anomalous Hall effect in CoRuTiGe arises from both intrinsic and extrinsic mechanisms. Additionally, a well-defined symmetric negative magnetoresistance is observed at low temperatures. These findings suggest that CoRuTiGe holds significant promise for spintronic applications.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 12 figures
Transport evidence of current-induced nematic Dirac valleys in a parity-time-symmetric antiferromagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
H. Sakai, Y. Miyamoto, M. Kimata, H. Watanabe, Y. Yanase, M. Ochi, M. Kondo, H. Murakawa, N. Hanasaki
Itinerant antiferromagnets with broken time-reversal symmetry have recently attracted attention, since their spin-split bands enable large magnetotransport responses comparable to ferromagnets despite the negligible spontaneous magnetisation. When the inversion symmetry is further broken by the antiferromagnetic order, the emerging odd-parity multipole order renders the bands spin-degenerate but asymmetric in the momentum space. For such parity-time-symmetric antiferromagnets, it has been predicted that electronic nematicity is induced by current, allowing unconventional nonlinear transport phenomena. However, their experimental evidence has been lacking. Here, we report nonreciprocal angular magnetoresistance in the layered Dirac material SrMnBi$ _2$ with parity-time-symmetric antiferromagnetic order in its Mn-Bi layers. By quantitatively modelling the angular and field dependencies using a phenomenological framework, we reveal that the observed nonreciprocal interlayer resistivity arises from the broken four-fold symmetry of the Dirac valleys in the Bi square net adjacent to the Mn-Bi layer. Furthermore, we demonstrate the alignment of parity-time-symmetric antiferromagnetic domains via current-field cooling, achieving electric-magnetic control of the $ f$ -wave polarity in momentum space. The observed switchable nonreciprocal transport associated with current-induced valley symmetry breaking paves the way for novel antiferromagnetic spintronic and valleytronic applications.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
17 pages, 4 figures
Machine Learning Prediction of Magnetic Proximity Effect in van der Waals Heterostructures: From Atoms to Moiré
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Lukas Cvitkovich, Klaus Zollner, Jaroslav Fabian
We introduce a machine learning framework that efficiently predicts large-scale proximity-induced magnetism in van der Waals heterostructures, overcoming the high computational cost of density functional theory (DFT). We apply it to graphene/Cr$ _2$ Ge$ _2$ Te$ _6$ , which exhibits a previously unrecognized dichotomy. Unlike the spin polarization at the Fermi level, which follows the pseudospin, the proximity-induced magnetic moments vary across carbon atoms, defying analytical modeling. To address this, we develop a Random Forest model trained on DFT data and employ Smooth Overlap of Atomic Positions descriptors to map the local ($ \sim 2,$ nm$ ^2$ ) atomic-scale geometry to the carbon magnetic moments. Besides demonstrating locality, the model reveals rich magnetic moiré textures. Crucially, this method can be broadly applied to orbital and spin proximity effects that are highly sensitive to local atomic environments and are beyond analytical description.
Materials Science (cond-mat.mtrl-sci)
Bulk photovoltaic effects in the Haldane model
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
The bulk photovoltaic effect (BPVE) refers to the direct current generation in a noncentrosymmetric material under illumination and can be applied to solar energy technology. BPVE includes injection and shift currents, led by the change of velocity and displacement of wave packet during optical transitions, respectively. We derive the constraints on the conductivity tensors imposed by mirror-time ($ \mathcal{MT}$ ) symmetry for two-dimensional systems. For the Haldane model, we show that linearly polarized light can induce shift and injection currents, which vanish under circularly polarized light as constrained by the three-fold rotation and $ \mathcal{MT}$ symmetry. Additionally, due to the presence of $ \mathcal{MT}$ symmetry, a separation of responses is observed in the Haldane model: one direction exhibits a time-reversal symmetry-allowed response, whereas another manifests a parity-time symmetry-allowed response. Across the topological phase transition, the injection current does not change sign, whereas shift current shows a sign flip. The vector field of the Hermitian connection in the Brillouin zone possesses vortices in the topological phase, but not in the trivial phase. Furthermore, we calculate the related quantum geometry, including Berry curvature, quantum metric and Hermitian connection, and demonstrate the microscopic quantum origin of the BPVE.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Non-Abelian Statistics for Bosonic Symmetry-Protected Topological Phases
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
Hong-Yu Wang, Bao-Zong Wang, Jian-Song Hong, Xiong-Jun Liu
Symmetry-protected non-Abelian (SPNA) statistics opens new frontiers in quantum statistics and enriches the schemes for topological quantum computing. In this work, we propose a novel type of SPNA statistics in one-dimensional strongly correlated bosonic symmetry-protected topological (SPT) phases and reveal its exotic universal features through a comprehensive investigation. Specifically, we show a universal result for a wide range of bosonic SPT phases described by real Hamiltonians: the SPNA statistics of topological zero modes fall into two distinct classes. The first class exhibits conventional braiding statistics of hard-core bosons. Furthermore, we discover a second class of unconventional braiding statistics, featuring a fractionalization of the first class and reminiscent of the non-Abelian statistics of symmetry-protected Majorana pairs. The two distinct classes of statistics have a topological origin in the classification of non-Abelian Berry phases in braiding processes of real-Hamiltonian systems, distinguished by whether the holonomy includes a reflection operation.. To illustrate, we focus on a specific bosonic SPT phase with particle number conservation and particle-hole symmetry, and demonstrate that both classes of braiding statistics can be feasibly realized in a tri-junction of the SPT phase with the aid of a controlled local defect. In this example, the zero modes are protected by unitary symmetries and are therefore immune to dynamical symmetry breaking. Numerical results support our theoretical predictions. Based on the tri-junction implementation, we demonstrate how to encode logical qubits and implement both single- and two-qubit gates using the two classes of SPNA statistics. We further propose feasible experimental schemes to realize these SPNA statistics and identify the parameter regimes that ensure high-fidelity braiding results.
Strongly Correlated Electrons (cond-mat.str-el)
21 pages, 10 figures
Nonadiabaticity under compression in metastable carbon monoxide-nitroxide mixtures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Reetam Paul, Jonathan C. Crowhurst, Stanimir Bonev
Carbon monoxide (CO) and nitrous oxide (N2O) both undergo profound structural and chemical transformations when compressed. While their individual high-P/T phase diagrams have been mapped in considerable detail, comparatively little attention has been paid to the mixtures in which the two species can couple through oxygen transfer, charge redistribution, and nonadiabatic dissociation pathways. Here we use comprehensive ab initio adiabatic/nonadiabatic molecular dynamics simulations, essentially a diabatic trajectory stitching approach, that chart the evolution of CO-N2O mixtures from van-der-Waals fluids to extended amorphous network solids over the range 0-160 GPa and 300-1500 K. We emphasize on (i) the sequence of gas to molecular crystal to polymerized amorphous solid reactive transitions that arise from an interplay between thermal and compression effects in metastable C-N-O mixtures, (ii) the role of N2O unimolecular dissociation in lowering the onset pressure for CO polymerization, and (iii) the emergence of nonadiabatic pathways, via thermal unimolecular dissociation of N2O, accompanied by spin-transition in oxygen atoms that can make C-N-O systems deviate from Born-Oppenheimer dynamics. This dominates the chemistry once the mixture enters the regime of bond-breaking temperatures (T>900 K).
Materials Science (cond-mat.mtrl-sci)
Operando Electron Microscopy of Nanoscale Electronic Devices on Non-Conductive Substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Menglin Zhu, Michael Xu, Zishen Tian, Colin Gilgenbach, Daniel Drury, Bridget R. Denzer, Ching-Che Lin, Deokyoung Kang, Lane W. Martin, James M. LeBeau
Achieving operating conditions comparable to ``bulk’’ electronic devices, such as thin film capacitors, during \textit{operando} electron microscopy remains challenging, particularly when devices are grown on non-conductive substrates. Limited precision of focused ion beam milling for sample preparation often necessitates the use of conductive substrates or artificially thick layers that differ from actual device architectures. These modifications can alter native strain, electrostatic boundary conditions, and ultimately device response. Here, we present a generic and versatile workflow for \textit{operando} biasing of thin-film capacitors in the (scanning) transmission electron microscope, including sample fabrication and device operation. By introducing a patterned insulating barrier adjacent to the bulk-characterized capacitors, our approach enables sample preparation without altering the original film structure. As a case study, we apply the method to a piezoelectric thin-film capacitor grown on an insulating substrate, and demonstrate that it preserves the boundary-condition-sensitive domain switching at the atomic scale under applied electric fields. Overall, the process can help to establish a foundation for systematic \textit{operando} studies of complex thin-film systems under representative bulk testing geometries.
Materials Science (cond-mat.mtrl-sci)
Dopant site occupancy determined by core-loss-filtered, position-averaged convergent beam electron diffraction
New Submission | Other Condensed Matter (cond-mat.other) | 2025-08-19 20:00 EDT
Michael Deimetry, Timothy C. Petersen, Matthew Weyland, Scott D. Findlay
In the elastic scattering regime, probe position-averaged convergent beam electron diffraction (PACBED) patterns have proven robust for estimating specimen thickness and mistilt. Through simulation, we show that core-loss-filtered PACBED patterns can be used to measure the site occupancy of a small concentration of dopants in an otherwise known crystal structure. By leveraging the reciprocity between scanning and conventional transmission electron microscopy, we interpret core-loss PACBED patterns using a strategy traditionally used for determining dopant concentrations via energy dispersive X-ray spectroscopy. We show that differences in the interaction range of different elements hinder a purely measurement-based quantification strategy, but that this can be overcome through comparison with simulations that generalize the Cliff-Lorimer k-factors.
Other Condensed Matter (cond-mat.other), Applied Physics (physics.app-ph)
Robust Topological Conduction in Bi2 Bi2Se3 Superlattices at Ambient Conditions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Lakshan Don Manuwelge Don, Md. Sakauat Hasan Sakib, Gracie Pillow, Sara McGinnis, Seth Shields, Joseph P. Corbett
Topologically protected surface states have garnered significant attention due to their robustness against perturbations and potential applications in optoelectronics. Bi2 Bi2Se3 is a topological semimetal composed of a 2D bismuthene sheet and a Bi2Se3 quintuple layer, forming an intrinsic superlattice. This study investigates the electronic structure and edge states of Bi2 Bi2Se3 [001] oriented films under ambient conditions through conducting atomic force microscopy (C-AFM). Point I-V spectroscopy and current imaging are used to characterize the surface and local transport properties of bismuthene and Bi2Se3 terminated layers. Our measurements reveal force dependent shifts in conduction mechanisms in both bismuthene and Bi2Se3, transitioning from direct tunneling (DT) at low forces and low biases, to Fowler Nordheim tunneling (FNT) at low forces and high biases, and eventually to a more ohmic like behavior at the highest forces. Under DT conditions on the bismuthene termination, we observed the Dirac cone in the dI/dV spectroscopy. Edge states are observed along the perimeter of the (001) terraces for both terminations, and are observed to have higher conductivity than the local terrace. Force-dependent imaging revealed an increase in the width of the edge state as force increased, until the conductive edge state appeared to cover the entire terrace. Furthermore, terrace heights display a force dependent distortion from the high tip forces, which indicates that the transition to the ohmic-like contact regime on either termination results from a complex interplay between strain and tip induced effects. All measurements were performed under ambient conditions, which demonstrates the robustness of the topological and edge states to ambient conditions.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Understanding high photocatalytic activity of the TiO2 high-pressure columbite phase by experiments and first-principles calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Jacqueline Hidalgo-Jimenez, Taner Akbay, Tatsumi Ishihara, Kaveh Edalati
The clean production of hydrogen as a zero-emission fuel can be done using photocatalysis, with TiO2 being one of the most promising photocatalysts. However, the activity of TiO2 anatase and rutile phases is still limited. In this study, an oxygen-deficient high-pressure phase of TiO2, columbite, is stabilized by a high-pressure torsion method. The phase is utilized as an active photocatalyst for hydrogen production, and the mechanism of its high activity is examined using density functional theory (DFT). The activity of columbite appears to be experimentally higher than that of the anatase phase. DFT calculations revealed that columbite does not have a narrow electronic bandgap, but its optical bandgap and light absorbance are improved by oxygen vacancies more significantly compared to anatase. Moreover, the water adsorption energy is higher and the surface activation energy for water splitting on the (101) atomic plane of columbite is lower than that for the active planes of anatase. In conclusion, although columbite is not a low-bandgap semiconductor, its large light absorbance and high surface catalytic activity make it a promising candidate for photocatalytic reactions.
Materials Science (cond-mat.mtrl-sci)
A multiple occupancy cell fluid model with competing attraction and repulsion interactions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
R. V. Romanik, O. A. Dobush, M. P. Kozlovskii, I. V. Pylyuk, M. A. Shpot
An analytically solvable cell fluid model with unrestricted cell occupancy, infinite-range Curie-Weiss-type attraction and short-range intra-cell repulsion is studied within the grand-canonical ensemble. Building on an exact single-integral representation of the grand partition function, we apply Laplace’s method to obtain asymptotically exact expressions for the pressure, density and equation of state. The model exhibits a hierarchy of first-order transitions, each terminating at a critical point. We determine the coordinates of the first five such points. Recasting the formalism in dimensionless variables highlights the explicit temperature dependence of all thermodynamic functions. This enables us to derive a closed-form expression for the entropy. The results reveal pronounced entropy minima around integer cell occupancies and reproduce density-anomaly isotherm crossings analogous to those in core-softened models.
Statistical Mechanics (cond-mat.stat-mech)
Hubbard energy dependence of electronic structures in rare-earth monoxides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Mizuki Tago, Tsukasa Kurachi, Takayuki Makino
To realize the significant potential of optical materials such as strongly electron-correlated open-shell rare-earth monoxides, understanding the electron-localization Hubbard parameters ($ U$ ) is of central importance. The Hubbard energy is believed to be material specific and constant. However, it has recently been pointed out that even subtle structural changes can induce changes in $ U$ parameters. For LuO, we theoretically evaluated $ U$ energy dependence of the differential transmission and reflectivity spectra to assess the impact of $ U$ energy on the optical properties. In addition to the conventional derivative-like contribution, we observed the influence of the Drude tail owing to $ U$ -induced plasma energy modulation. Given the typical detection sensitivity of differential spectroscopy ($ \sim 1 \times 10^{-4}$ ), even a few meV modulations in $ U$ are sufficient for a detectable spectral response.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
13 pages, 6 figures, accepted for publication in Jpn. J. Appl. Phys (this https URL)
Structural, optical, and dielectric properties of Cr-doped ZnO films via DC magnetron sputtering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Men Guo, Gilad Orr, Paul Ben Ishai, Xia Zhao, Shlomo Glasser
Cr-doped ZnO films were fabricated by a new but feasible method, that is, annealing Cr-Zn layers deposited via DC magnetron sputtering in air. Microstructures of the films were investigated using X-ray diffraction, scanning electron microscopy, and atomic force microscopy, intrinsic point defects were identified via photoluminescence spectroscopy, and optical and dielectric properties were analyzed using a UV-vis spectrophotometer and dielectric spectrometer, respectively. It was found that the average grain sizes decrease (56.34 - 39.50 nm), the band gap increases (from 3.18 to 3.23 eV), and the transmittance (at 600 nm) decreases (from 91% to 83%) with increasing Cr. Two activation energies of conduction increase after doping Cr, indicating enhanced temperature stability. At optimal Cr levels, ZnO films exhibit high transmittance and conductivity, exhibiting potential for transparent electrode development. This method can be extended to other doped ZnO films, such as Al-doped ZnO transparent electrodes, to achieve simultaneous improvements in transmittance, conductivity, and stability for flexible and wearable applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
20 pages including references and Supplemental Information, 13 figures, and 2 tables
Fabry-Perot interference in three dimensional second-order topological insulator constrictions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
The gapless chiral hinge states of three dimensional second-order topological insulators (SOTIs) support a quantized conductance plateau on thick nanowire. Here, we numerical study the conductance of SOTI constrictions. According to finite size effects, the hinge states in narrow region could be hybridized, which will induce reflection at the two ends of constrictions. The conductance exists the Fabry-Perot oscillation pattern because of multiple reflections. We also study the impact of the magnetic field on the Fabry-Perot interference. We show the dimensional effect that the magnetic field leads to the electrons being localized on two hinges. Our results are robust against moderate disorder so that we expect these Fabry-Perot patterns could be observed in experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Anomalous Nernst Effect and Its Implications for Time-Reversal Symmetry Breaking in Kagome Metal ScV6Sn6
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
Yazhou Li, Saizheng Cao, Jiaxing Liao, Jiajun Ma, Yuwei Zhang, Tao Li, Jialu Wang, Chenchao Xu, Jianhui Dai, Chao Cao, Yu Song, Peijie Sun, Yuke Li
The nonmagnetic kagome metal ScV6Sn6 displays an unconventional charge order (CO) accompanied by signatures of an anomalous Hall effect, hidden magnetism, and multiple lattice instabilities. In this study, we report the observation of unconventional anomalous thermoelectric properties. Notably, unexpected anomalous transverse Nernst signals reach a peak value of ~4 {\mu}V/K near the TCDW ~92 K in ScV6Sn6, and these signals persist in the charge-ordered state as the temperature decreases to 10 K. Furthermore, both thermopower and thermal conductivity exhibit significant changes under magnetic fields, even in the nonmagnetic ground state. These observations strongly suggest the emergence of time-reversal symmetry breaking in ScV6Sn6, as supported by muon spin relaxation ({\mu}SR) measurements. While hidden magnetism represents the most plausible origin, alternative mechanisms involving orbital currents and chiral charge order remain possible.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 4 figures, to appear in SCIENCE CHINA Physics, Mechanics and Astronomy
Waveguiding in two-dimensional Floquet non-Abelian topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Yujie Zhou, Changsen Li, Xiumei Wang, Xingping Zhou
Topological phases characterized by non-Abelian charges have garnered increasing attention recently. Although Floquet (periodic-driving) higher-order topological phases have been explored at the single-particle level, the role of interactions in non-Abelian topological insulators with multiple entangled energy gaps remains incompletely understood. In this work, we extend previous research by investigating higher-order topological phases featuring non-Abelian charges through Floquet engineering. Here we construct a model for two-dimensional non-Abelian higher-order topological phases on a square lattice subjected to two-step periodic driving. We find that the corner and edge states emerge and appear in all energy gaps despite the quaternion charge being trivial. Moreover, spatially exchanging the driving generates exotic interface modes-a hallmark of non-Abelian dynamics, namely non-commutativity. Notably, the non-zero composite Chern number demonstrates the non-triviality of the Floquet non-Abelian system with. We further reveal that the configuration of these quaternion-charge edge states is entirely determined by the quadruple degenerate phase-band singularities in the time evolution. Our work provides a platform for studying higher-order topological states and non-equilibrium quantum dynamics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Effects of Defects on Thermal Transport across Solid/Solid Heterogeneous Interfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Ershuai Yin, Wenzhu Luo, Lei Wang, Qiang Li
During the fabrication of heterogeneous structures inside chips, impurities and defects are inevitably introduced. However, the mechanism by which defects affect interfacial heat transport remains unclear. In this work, a microscale thermal transport model is developed by combining first-principles calculations with Monte Carlo simulations, explicitly accounting for the effects of defects. The effects of defect concentration and location on thermal transport characteristics are investigated for four heterointerfaces: Si/SiC, GaN/SiC, Si/Diamond, and GaN/Diamond. Temperature distribution, spectral thermal conductance, average phonon scattering numbers, and interfacial thermal conductance (ITC) are compared under different conditions. The results show that, for Si/SiC, Si/Diamond, and GaN/Diamond interfaces, introducing defects weakens heat transport. Higher defect concentration leads to lower ITC. Furthermore, when defects are in SiC or Diamond, which have broader phonon spectral distributions, their impact on ITC is weaker. For the GaN/SiC interface, defects in GaN reduce ITC, while defects in SiC enhance ITC. At a defect concentration of 0.05, ITC decreases by 54.1% when defects are present in GaN, but increases by 57.2% when defects are present in SiC. This behavior arises from defect-induced phonon energy redistribution near the interface. The redistribution increases the population of low-frequency phonons, which are more capable of crossing the interface, thus enhancing heat transfer. This study enriches the fundamental understanding of thermal transport across semiconductor heterointerfaces and guides the design and fabrication of high-ITC heterostructures.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
18 pages, 11 figures
High-field NMR study of field-induced states in Pb(TiO)Cu$_4$(PO$_4$)$_4$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
Y. Ihara, T. Kanda, Y. Kato, Y. Motome, K. Matsui, K. Kindo, Y. Kohama, T. Kimura, K. Kimura
The square cupola antiferromagnet Pb(TiO)Cu$ _4$ (PO$ _4$ )$ _4$ exhibits the intriguing magnetoelectric responses arising from the consecutive change in the magnetic quadrupolar-type configuration of magnetic moments under external magnetic fields higher than 15 T. To clarify the high-field magnetic structures in Pb(TiO)Cu$ _4$ (PO$ _4$ )$ _4$ , an NMR measurement was performed in pulsed fields up to 32.2 T significantly extending the field range accessible by superconducting magnets. The double-peak structure of NMR spectra emerging above 29 T applied along the [001] direction evidences the successive magnetic transitions. The field dependence of NMR spectra was analyzed on the basis of cluster mean-field theory, which allows us to propose possible magnetic structures for the high-field magnetic states.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
9 pages, 6 figures
Chiral Altermagnetic Second-Order Topological Phases and Sign-Reversible Transport
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Chengwu Xie, Zhenzhou Guo, Wenhong Wang, Weizhen Meng, Xiaotian Wang, Zhenxiang Cheng, Xiaodong Zhou
Chiral materials are rare in nature, yet they play a fundamental role in modern physics due to their unconventional topological properties and transport responses. While chiral charge and structural orders have been extensively studied, chiral magnetic order – particularly in altermagnets (AMs) – remains largely unexplored. Here, we demonstrate that the experimentally well-characterized three-dimensional metal-organic framework K[Co(HCOO)$ _3$ ] represents the first realization of a chiral second-order topological insulator with altermagnetic order. This system hosts $ \emph{g}$ -wave spin-split bands, controllable second-order topological states, and chirality-locked anomalous transport properties. Its second-order topological phase manifests as alternating spin-up and spin-down hinge modes along the boundaries of hexagonal nanotubes. Remarkably, these spin-polarized hinge states can be switched through lattice chiral inversion. Simultaneously, the anomalous Hall effect and magneto-optical effects exhibit reversed signs in left/right-handed enantiomers, substantiating a universal chirality-controlled response across both electronic and optical channels. Our results establish chiral AMs as a promising platform for non-volatile topological spintronics, opening new avenues for manipulating quantum transport via lattice chirality.
Materials Science (cond-mat.mtrl-sci)
Extraction of classical ergotropy
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
Finding the time dependent perturbation that extracts the maximal amount of energy (a.k.a. ergotropy) from a thermally isolated quantum system is a central, solved, problem in quantum thermodynamics. Notably, the same problem has been long studied for classical systems as well, e.g., in the field of plasma physics, but a general solution is still missing there. By building on the analogy with the quantum solution, we provide the classical ergotropy extraction driving: it consists of an instantaneous quench followed by an adiabatic return. We illustrate how the solution, which is valid under an ergodic assumption, is instrumental to finding the ergotropy extracting driving in more general cases. We also show that, just like in the quantum case, the classical ergotropy splits into a coherent and an incoherent part. The presented results open new ways for practical energy recovery in the classical regime while suggesting that there is nothing genuinely quantum in the quantum ergotropy problem.
Statistical Mechanics (cond-mat.stat-mech), Plasma Physics (physics.plasm-ph), Quantum Physics (quant-ph)
7 pages, 1 figure
Controlling quantum scars and engineering subharmonic responses with a two frequency drive
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-19 20:00 EDT
Pinaki Dutta, Kamal L Panigrahi, Vishwanath Shukla
We demonstrate that a continuous two frequency drive is a versatile and robust protocol to control the lifetime of quantum many body scars and to engineer non-equilibrium phases of driven quantum matter. By modulating the frequency ratio $ c$ (any rational number), we systematically explore prethermal features across a broad frequency range. For small integer values of $ c$ , we observe ergodicity breaking even at moderately low frequencies, signaling long-lived scarred dynamics. By continuously increasing $ c$ , one can generate non-monotonic transitions between ergodic and non-ergodic dynamics. These observations are consistent with the predictions of an effective Floquet Hamiltonian based approach. Furthermore, we exploit this tunability to engineer fractional subharmonic responses, highlighting the potential of two-frequency driving as a theoretical platform for controlling scars, prethermalization, and time crystal-like behavior.
Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
13 pages, 13 figures
Strongly correlated stochastic systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
This thesis develops exact analytical tools to study strongly correlated stochastic systems, with a focus on extreme value statistics, gap statistics, and full counting statistics in multi-particle processes. A central contribution is the universal characterization of conditionally independent identically distributed variables-random variables that become independent upon conditioning on latent parameters. This structure arises naturally in systems with stochastic resetting, a mechanism that generates strong long-range correlations while retaining analytical tractability.
Using this framework, we derive universal closed-form expressions for several observables across diverse models, including Brownian motion, Levy flights, ballistic particles, and Dyson Brownian motion, under various resetting protocols. In particular, we demonstrate that resetting induces analytically tractable non-equilibrium steady states.
Theoretical predictions are supported by numerical comparisons and experimental comparisons in systems such as diffusive particles in switching harmonic traps. Applications to search optimization are also explored, identifying regimes where resetting enhances or impairs first-passage efficiency, and proposing rescaling-based protocols that outperform traditional resetting.
Statistical Mechanics (cond-mat.stat-mech)
Doctoral Thesis
Fermi velocity and magic angle renormalization in twisted bilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Miguel Sánchez Sánchez, José González, Tobias Stauber
We discuss the Fermi-velocity renormalization in twisted bilayer graphene due to Coulomb exchange interaction within an atomistic tight-binding model. Adopting the Slater-Koster parametrization for the hopping parameters obtained from first principles, our results only depend on the effective dielectric constant $ \epsilon$ and the Hubbard-interaction $ U$ . The Fermi velocity of graphene increases twist-angle independent by $ ~25%$ for $ \epsilon=10$ and $ U=4eV$ , leading to an increase by more than $ 100%$ of the flat bandwidth at twist-angle $ \theta=1.4^\circ$ . Including also the renormalization of the out-of-plane hopping terms, we further observe a shift of the magic angle from $ 1.02^\circ$ to $ 0.96^\circ$ . Our results offer a microscopic explanation of the critical temperature, $ T_c$ , as function of the twist angle where the largest $ T_c$ is found at $ \theta_{max}=1.1^\circ$ . For $ \theta>\theta_{max}$ , $ T_c$ is obtained from the Bethe-Salpeter equation of the Cooper channel. For $ \theta<\theta_{max}$ , the discussion is based on the critical line of the Berezinskii-Kosterlitz-Thouless phase transition.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
11 pages, 9 figures
Entropy-driven phase transition in a non-collinear antiferromagnet due to higher-order exchange interactions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Leo Kollwitz, Moritz A. Goerzen, Bjarne Beyer, Hendrik Schrautzer, Stefan Heinze
The triple-Q state arises due to the superposition of three symmetry equivalent spin spirals stabilized by higher-order exchange interactions. It has been predicted more than 20 years ago but was only recently discovered in a Mn monolayer on the Re(0001) surface. To date little is known about the thermodynamic properties of this intriguing non-coplanar spin state. Here, we reveal a low-temperature phase transition between the triple-Q and the row-wise antiferromagnetic state in this system via Monte Carlo simulations based on an atomistic spin model parametrized by density functional theory. By modeling the free energy landscape in terms of thermal excitations we derive an analytical expression of the partition function, which allows us to prove that the phase transition is driven by entropy. The predicted phase transition is not unique to Mn/Re(0001) but appears for a wide range of magnetic interaction parameters and is expected to occur also for other multi-Q states.
Materials Science (cond-mat.mtrl-sci)
Quantum nature of gravity in self-bound quantum droplets
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-08-19 20:00 EDT
Asma Tahar Taiba, Abdelaali Boudjemaa
We explore the possibility of testing the quantum nature of the gravitational field with an ultracold self-bound quantum droplet of one-dimensional Bose-Bose mixtures. To this end, we solve variationally and numerically the underlying generalized Gross-Pitaevskii equation which includes the effects of quadratic and cubic nonlinearities. We derive the associated generalized uncertainty principle and its corresponding minimal length. The obtained modified uncertainty relation enables us to search for the quantum gravity signatures in both small and large droplets. We place bounds on the parameter using existing experimental data from recent experiment of dilute droplets of potassium. Improved upper bounds on the generalized uncertainty principle parameters are found from our analysis.
Quantum Gases (cond-mat.quant-gas), High Energy Physics - Theory (hep-th)
6 pages, 5 figures
Edge-state competition in a 2D topological insulator-semiconductor heterostructure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Wei Li, Pier Philipsen, Thomas Brumme, Thomas Heine
Quantum spin Hall edge transport in two-dimensional transition-metal dichalcogenides depends on whether their one-dimensional edge channels are preserved under realistic substrates and device boundaries. Here we implement spin-orbit coupling in DFTB and GFN-xTB within the Amsterdam Modeling Suite, and apply it to 1T$ ‘$ /2H WSe$ _2$ heterostructures. Edge-projected spectra reveal robust edge states in 1T$ ‘$ ribbons; and these states remain robust against a laterally infinite 2H substrate, which only shifts the Dirac point via long-wavelength corrugation without introducing additional in-gap states. By contrast, terminated 2H edges generate trivial dispersion branches in the same energy window that hybridize only weakly with the topological edge modes. In the bulk, Fermi-level states are 1T$ ‘$ -derived; at the small twist angle, lattice-relaxation-induced strain drives miniband reconstruction, whereas at the large twist angle, the layers become electronically decoupled. These findings suggest the conditions – controlled twist angle and avoidance of terminated 2H edges – for achieving quantized conductance and unambiguous spectroscopic
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Precision and cost of feedback cooling
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
Andreas Dechant, Jakob Hüpfl, Shuta Kobayashi, Sosuke Ito, Stefan Rotter
We investigate the consequences of information exchange between a system and a measurement-feedback apparatus that cools the system below the environmental temperature. A quantitative relationship between entropy pumping and information acquired about the system is derived, showing that, independent of the concrete realization of the feedback, the latter exceeds the former by a positive amount of excess information flow. This excess information flow satisfies a trade-off relation with the precision of the feedback force, which places strong constraints on both the information-theoretic cost of feedback cooling and the required magnitude of the feedback force. From these constraints, a fundamental lower bound on the energetic cost of optical feedback cooling is derived. Finally, the results are demonstrated for feedback cooling by coherent light scattering. We show that measurement precision is the major factor determining the attainable temperature. Precise measurements can also be leveraged to reduce the required feedback force, leading to significantly more energy-efficient cooling close to the fundamental bound for realistic parameter values.
Statistical Mechanics (cond-mat.stat-mech), Optics (physics.optics)
11+11 pages, 5 figures
Theoretical Investigation of Performance-Improved Ferroelectric Tunnel Junction Based on Trap-Assisted Tunneling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
CMOS-compatible HfO2-based ferroelectric tunnel junction (FTJ) has attracted significant attention as a promising candidate for in-memory computing (IMC) due to its extremely low power consumption. However, conventional FTJs face inherent challenges and hinder their practical applications. Insufficient current density (JON) and limited on-off current ratios in FTJs are primarily constrained by their dependence on direct tunneling (DT) and Fowler-Nordheim (FN) tunneling mechanisms. Building on previous experimental results, this paper proposes a trap-assisted tunneling (TAT)-based FTJ that leverages the TAT mechanism to overcome these limitations. A comprehensive FTJ model integrating ferroelectric (FE) switching, DT, FN tunneling, and TAT mechanisms is developed, enabling detailed analyses of the trap conditions and their impact on performance. Through systematic optimization of trap parameters and device structure, the TAT-based FTJ achieves ultra-high JON and a remarkable on-off current ratio, meeting the nanoscale IMC requirements. The results highlight the potential of TAT-based FTJs as high-performance memory solutions for IMC applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Frequency Domain Berry Curvature Effect on Time Refraction
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Shiyue Deng, Yang Gao, Qian Niu
We demonstrate that there exist frequency domain Berry curvature in the wave function of photons in dispersive optical systems. This property arises from the frequency dispersion of its dielectric function, which makes Maxwell equations a non-standard eigenvalue equation, with the eigenvalue (frequency) appearing inside the operator itself. We study this new Berry curvature effect on time refraction of magnetoplasmon-polariton as an example. It can induce deflection in the trajectory of a photon and make the ray swing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Inertia Tames Fluctuations in Autonomous Stationary Heat Engines
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-08-19 20:00 EDT
Enrique P. Cital, Viktor Holubec
Thermodynamic uncertainty relations (TURs) provide fundamental constraints on the interplay between power fluctuations, entropy production, and efficiency in overdamped stationary autonomous heat engines. However, their validity in underdamped regimes remains limited and less explored. Here, we analytically and numerically study a physically realizable autonomous heat engine composed of two underdamped continuous degrees of freedom coupled to a two-level system. We show that this nonlinear setup can robustly violate TUR-based trade-offs by exploiting resonant coupling, effectively using one underdamped mode as an internal periodic drive. When this coupling is suppressed, the system recovers TUR-like bounds consistent with overdamped theory. Importantly, we demonstrate that the strongest suppression of current fluctuations occurs in a resonance regime that can be directly inferred from mean current measurements - a quantity typically much easier to access experimentally than fluctuations. Our results reveal new pathways to circumvent classical TUR constraints in underdamped systems and provide practical guidelines for designing efficient, precise microscopic engines and autonomous clocks.
Statistical Mechanics (cond-mat.stat-mech)
14 pages, 7 figures
A collisional model of odd fluids: from Boltzmann equation to chiral hydrodynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Ege Eren, Michel Fruchart, Vincenzo Vitelli
When the time-reversal and parity symmetries in a fluid are broken, transverse transport coefficients can arise in response to perturbations, an example being odd viscosity. We refer to these systems as odd fluids. While much progress has been made in the continuum theory of odd-viscous fluids, and non-collisional models for odd viscous fluids have been proposed, a classical microscopic description in which the transverse responses originate from collisions is lacking. In this paper, we show that a dilute granular gas of rough and inelastic particles driven by a constant torque is a minimal microscopic model of an odd fluid. By applying the methods of Boltzmann kinetic theory, we obtain a hydrodynamic description of the microscopic model. Then, using the method of adiabatic elimination, we numerically compute all the response coefficients of the model, explicitly showing that the model has many odd response terms. Our theory predicts that certain odd response coefficients can change sign even when the direction of the external torque is fixed. While we choose a particular case, the procedure we present can be applied to any collisional model. We also present a semi-quantitative method to determine the hydrodynamic variables of the theory by observing the eigenvalue spectrum of the linear collision operator.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
27 pages, 7 figures
Thermoelectricity evidence for quantum criticality in clean infinite-layer nickelate films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-08-19 20:00 EDT
Xu Zhang, Chihao Li, Mingwei Yang, Yan Zhao, Zhitong An, Danfeng Li, Liang Qiao, Haichao Xu, Rui Peng, Donglai Feng, Shiyan Li
We investigate the Seebeck coefficient ($ S$ ) in infinite-layer nickelate films with different disorder levels. The disordered NdNiO$ _{2}$ film exhibits a flat $ S/T$ curve, whereas cleaner samples display a logarithmic divergence with decreasing temperature, followed by a pronounced hump'' near 25 K. These distinct behaviors reveal a disorder-driven transition from band-structure-dominated transport to quantum-critical-dominated transport. Below the hump’’ temperature, four-fold symmetry breaking is observed in the in-plane angular magnetoresistance, indicating the presence of short-range antiferromagnetic order in parent infinite-layer nickelate films. Furthermore, the logarithmic divergence in $ S/T$ is also observed in a clean superconducting Sm$ _{0.73}$ Ca$ _{0.05}$ Eu$ _{0.22}$ NiO$ _{2}$ film, where it coexists with linear-in-temperature resistivity over the same temperature range. These findings demonstrate the existence of quantum criticality over a wide doping range in clean infinite-layer nickelate films, similar to cuprates, which highlights the central role of antiferromagnetic spin correlations in their superconducting pairing mechanisms.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 4 figures
Likelihood-Based Heterogeneity Inference Reveals Non-Stationary Effects in Biohybrid Cell-Cargo Transport
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Jan Albrecht, Lara S. Dautzenberg, Manfred Opper, Carsten Beta, Robert Großmann
Variability of motility behavior in populations of microbiological agents is an ubiquitous phenomenon even in the case of genetically identical cells. Accordingly, passive objects introduced into such biological systems and driven by them will also exhibit heterogeneous motion patterns. Here, we study a biohybrid system of passive beads driven by active ameboid cells and use a likelihood approach to estimate the heterogeneity of the bead dynamics from their discretely sampled trajectories. We showcase how this approach can deal with information-scarce situations and provides natural uncertainty bounds for heterogeneity estimates. Using these advantages we particularly uncover that the heterogeneity in the system is time-dependent.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
9 pages, 4 figures
Observation of Altermagnetic Spin Splitting in an Intercalated Transition Metal Dichalcogenide
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Milo Sprague, Mazharul Islam Mondal, Anup Pradhan Sakhya, Resham Babu Regmi, Surasree Sadhukhan, Arun K. Kumay, Himanshu Sheokand, Igor I. Mazin, Nirmal J. Ghimire, Madhab Neupane
Altermagnetism is a novel magnetic phase combining characteristics of both antiferromagnetism and ferromagnetic ordering. Despite growing theoretical interest in altermagnetic materials, reports of experimentally verified high Neel temperature layered compounds are limited or remain to be firmly established. Here, we present an angle resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) study of Co1/4TaSe2, a compound we identify as a layered altermagnetic material. Magnetic susceptibility measurements confirm type A antiferromagnetic ordering with a Neel temperature of 178 K. Our ARPES measurements reveal an electronic band structure in excellent agreement with DFT calculations, demonstrating clear signatures of altermagnetic spin splitting at the Fermi surface. Furthermore, temperature dependent ARPES reveals a reconstructed valence band structure, with observable band shifts and the closing of energy gaps upon heating above the Neel temperature (TN), consistent with the suppression of altermagnetic order. These findings establish Co1/4TaSe2 as a promising platform for exploring altermagnetic phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7 pages, 3 figures
Skyrmion Lattice Domain Formation in a Non-Flat Energy Landscape
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Raphael Gruber, Jan Rothörl, Simon M. Fröhlich, Maarten A. Brems, Tobias Sparmann, Fabian Kammerbauer, Maria-Andromachi Syskaki, Elizabeth M. Jefremovas, Sachin Krishnia, Asle Sudbø, Peter Virnau, Mathias Kläui
Magnetic skyrmions are chiral spin structures with non-trivial topology that comprise two-dimensional quasi-particles and are promising information carriers for data storage and processing devices. Skyrmion lattices in magnetic thin films exhibit Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) phase transitions and have garnered significant interest for studying emergent 2D phase behavior. In experimental skyrmion lattices, the main factor limiting the quasi-long-range order in thin films has been the non-flat energy landscape - often referred to as pinning effects. We demonstrate direct control of the skyrmion lattice order by effectively tuning the energy landscape employing magnetic field oscillations. By quantifying lattice order and dynamics, we explore how domain boundaries form and evolve due to pinning effects in Kerr microscopy experiments and in Brownian dynamics simulations, offering a pathway to control and study emergent skyrmion lattice properties and 2D phase behavior.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Neutralizing Optical Defects in GeSn
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Nirosh M. Eldose, Dinesh Baral, Diandian Zhang, Fernando Maia de Oliveira, Hryhorii Stanchu, Mohammad Zamani-Alavijeh, Yuriy I. Mazur, Wei Du, Shui-Qing Yu, Gregory J. Salamo
Reports of photoluminescence from GeSn grown on Ge substrates by molecular beam epitaxy have been limited. We find that one limiting factor to observing photoluminescence is due to localized defect states marked by photoluminescence at 2400 nm and originating from the Ge substrate and buffer layer. In this study, we report on an optical study utilizing doped Ge(001) substrates to effectively suppress defect-related photoluminescence in GeSn layers by filling localized defect trap states. For this experiment, a GeSn layer with Sn content up to 10.5% was grown on a doped Ge(001) substrate. Analysis of the physics of the photoluminescence spectrum collected from the GeSn thin film shows an emission at the expected wavelength of 2300 nm for 10.5% Sn content and the absence of the typically observed defect related signal at 2400 nm. This understanding is further confirmed using short pulse optical excitation of the GeSn grown on undoped Ge substrates.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
16 pages, 5 figures, original manuscript
Macroscopic coherence and vorticity in room-temperature polariton condensate confined in a self-assembled perovskite microcavity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Martin Montagnac, Yesenia A. García Jomaso, Emiliano Robledo Ibarra, Rodrigo Sánchez-Martínez, Moroni Santiago García, César L. Ordóñez-Romero, Hugo A. Lara-García, Arturo Camacho-Guardian, Giuseppe Pirruccio
Exciton-polariton Bose-Einstein condensation at room temperature offers a promising pathway toward quantum photonic technologies that can operate under ambient conditions. A key challenge in this field is to engineer a controlled platform where strong confinement, nonlinear interactions, and structural disorder coexist, unlocking access to rich collective behavior and unconventional condensate dynamics. We demonstrate polariton condensation in CsPbBr$ _3$ microplatelets that self-assemble into whispering gallery mode microresonators featuring tight lateral photon confinement finely balanced with intrinsic disorder. The system exhibits hallmark signatures of out-of-equilibrium condensation, including a non-linear increase in emission intensity, spectral narrowing, and interaction-induced blueshift. Intrinsic disorder subtly reshapes the cavity energy landscape, inducing condensate fragmentation and enabling direct optical access to the condensate wavefunction. Interferometric measurements reveal extended phase coherence, whereas characteristic fork-shaped fringe dislocations confirm the presence of quantized vortices pinned by the disordered potential. These topological excitations underscore the rich physics driven by the interplay of gain, loss, confinement, and disorder. Our work establishes a scalable platform for investigating driven-dissipative quantum fluids of light at room temperature, where the intrinsic disorder balances optical confinement and provides a window into condensate wavefunction, coherence, and vortex phenomena. This study system opens new opportunities for exploring many-body physics and potentially advancing topological photonics in integrable microcavity architectures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Optics (physics.optics)
10 pages and 5 figures (main text). 7 pages and 12 figures (Supplementary Information). Comments are very welcome
Magnetic Order in Pulsed Laser Deposited (Fe,Ni)5GeTe2 Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-08-19 20:00 EDT
Tamal Kumar Dalui, John Derek Demaree, Thomas Parker, Ramesh C. Budhani
We report the successful growth of highly textured thin films of (Fe,Ni)5GeTe2 two-dimensional ferromagnet on c-plane sapphire using pulsed laser deposition. Structural characterization via X-ray diffraction confirms preferential orientation along the (000l) direction, indicative of a high crystallographic texture. These films of van der Waals (vdW) type interplanar bonding exhibit robust ferromagnetism with a Curie temperature reaching = 495 K. Electrical transport measurements reveal a clear anomalous Hall effect, with an anomalous Hall conductivity and Hall angle (%) of = 20 ohm-1cm-1 and = 0.90, respectively. Furthermore, the magnetoresistance displays a pronounced dependence on film thickness, highlighting the tunability of spin-dependent transport in these vdW ferromagnetic thin films.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Noise signatures of a charged Sachdev-Ye-Kitaev dot in mesoscopic transport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Andrei I. Pavlov, Mikhail N. Kiselev
We investigate quantum noise in a mesoscopic quantum dot serving as a realization of the charged Sachdev-Ye-Kitaev (SYK) model weakly coupled to a fermionic lead via a tunnel contact. We find noise signatures under voltage and temperature biases that can serve as clear markers of the SYK physics in experiments with related setups. We develop a linear response theory that treats all types of noise on the same footing and generalizes a concept of transport coefficients for charge and heat currents, as well as relations between them, to equilibrium noise power. Within this theory, we find characteristic scaling of the noise coefficients with temperature in all regimes that can be relevant for experimental realizations of the SYK dots, find a set of universal constants, with their values being unique to the SYK physics, that connect these coefficients, and characterize noise manifestations of the Coulomb blockade. Beyond SYK systems, these results may serve as a general framework for identification of non-Fermi-liquid signatures in mesoscopic transport and provide additional observables for experiments on thermoelectric phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
SO(n) Affleck-Kennedy-Lieb-Tasaki states as conformal boundary states of integrable SU(n) spin chains
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-08-19 20:00 EDT
Yueshui Zhang, Ying-Hai Wu, Meng Cheng, Hong-Hao Tu
We construct a class of conformal boundary states in the $ \mathrm{SU}(n)_1$ Wess-Zumino-Witten (WZW) conformal field theory (CFT) using the symmetry embedding $ \mathrm{Spin}(n)_2 \subset \mathrm{SU}(n)_1$ . These boundary states are beyond the standard Cardy construction and possess $ \mathrm{SO}(n)$ symmetry. The $ \mathrm{SU}(n)$ Uimin-Lai-Sutherland (ULS) spin chains, which realize the $ \mathrm{SU}(n)_1$ WZW model on the lattice, allow us to identify these boundary states as the ground states of the $ \mathrm{SO}(n)$ Affleck-Kennedy-Lieb-Tasaki spin chains. Using the integrability of the $ \mathrm{SU}(n)$ ULS model, we analytically compute the corresponding Affleck-Ludwig boundary entropy using exact overlap formulas. Our results unveil intriguing connections between exotic boundary states in CFT and integrable lattice models, thus providing deep insights into the interplay of symmetry, integrability, and boundary critical phenomena.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
22 pages, 3 figures
Negative drag force on beating flagellar-shaped bodies in active fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-08-19 20:00 EDT
Timo Knippenberg, Robin Bebon, Thomas Speck, Clemens Bechinger
We experimentally investigate the drag force exerted by a suspension of light-induced active particles (APs) on a translating and beating idealized flagellum-shaped object realized through negative phototactic interactions with the APs. We observe both positive and negative drag forces, depending on the beating frequency and translational velocity, driven by the dynamic redistribution of APs in response to the object’s motion. These findings are supported by numerical simulations and an analytical model, extendable to a range of slender geometries. Our results illustrate the complex interplay between geometric body changes and the density distribution in active baths, which may also be relevant for microrobotic applications.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
to appear in PRL
Topological invariant for finite systems in the presence of disorder
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Robert Eissele, Binayyak B. Roy, Sumanta Tewari, Tudor D. Stanescu
Topological invariants, rigorously defined only in the thermodynamic limit, have been generalized to topological indicators applicable to finite-size disordered systems. However, in many experimentally relevant situations, such as semiconductor-superconductor (SM-SC) hybrid nanowires hosting Majorana zero modes, the interplay between strong disorder and finite-size effects renders these indicators (e.g., the so-called topological visibility) biased and ill-defined, significantly limiting their usefulness. In this paper, we propose the topological invariant rigorously defined for an infinite system constructed by periodically repeating the original finite disordered system, as a topological indicator. Using the one-dimensional SM-SC hybrid nanowire as an example, we show that this general and transparent approach yields faithful topological indicators free from the biases affecting commonly used finite-size indicators, capturing the nature (topological or trivial) of the phase at generic points in parameter space, and providing a reliable tool for interpreting experimental results.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Strain-induced Ettingshausen effect in spin-orbit coupled noncentrosymmetric metals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
Gautham Varma K, Azaz Ahmad, Gargee Sharma
Elastic deformations couple with electronic degrees of freedom in materials to generate gauge fields that lead to interesting transport properties. Recently, it has been well studied that strain-induced chiral magnetic fields in Weyl semimetals lead to interesting magnetotransport induced by the chiral anomaly (CA). Recent studies have revealed that CA is not necessarily only a Weyl-node property, but is rather a Fermi surface property, and is also present in a more general class of materials, for example, in spin orbit-coupled noncentrosymmetric metals (SOC-NCMs). The interplay of strain, CA, and charge and thermomagnetic transport in SOC-NCMs, however, remains unexplored. Here we resolve this gap. Using a tight-binding model for SOC-NCMs, we first demonstrate that strain in SOC-NCMs induces anisotropy in the spin-orbit coupling and generates an axial electric field. Then, using the quasi-classical Boltzmann transport formalism with momentum-dependent intraband and interband scattering processes, we show that strain in the presence of external magnetic field can generate temperature gradients via the Nernst-Ettingshausen effect, whose direction and behavior depends the on interplay of multiple factors: the angle between the applied strain and magnetic field, the presence of the chiral anomaly, the Lorentz force, and the strength of interband scattering. We further reveal that time-reversal symmetry breaking in the presence of an external magnetic field generates the Berry-curvature-driven anomalous Ettingshausen effect, which is qualitatively distinct from the conventional Lorentz-force-driven counterpart. In light of recent and forthcoming theoretical and experimental advances in the field of SOC-NCMs, we find our study to be particularly timely and relevant.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 8 figures
Magnetic Interactions of Wigner Crystal in Magnetic Field and Berry Curvature: Multi-Particle Tunneling through Complex Trajectories
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-08-19 20:00 EDT
We study how a weak perpendicular magnetic field $ B$ and a Berry curvature $ \Omega$ modify the magnetic interactions of a two-dimensional Wigner crystal (WC), using the semi-classical large-$ r_s$ expansion. When only a magnetic field is present, various ring-exchange interactions arise from electron tunneling along {\it complex} trajectories, which constitute {\it complex instanton} solutions of the coordinate-space path integral. To leading order in $ B$ , each ring-exchange constant acquires an Aharonov-Bohm (AB) phase equal to the magnetic flux enclosed by the real tunneling trajectory of the $ B=0$ problem. This effect is directly relevant to two-dimensional electron systems with a small $ g$ -factor ($ g \ll 1$ ). In the presence of a Berry curvature, multi-particle tunneling must be considered in a (complexified) phase space $ ({\bf r}, {\bf k})$ . To leading order in $ \Omega$ , the exchange constants acquire the Berry phase enclosed by a {\it purely imaginary} trajectory in a momentum space. Finally, when both $ B$ and $ \Omega$ are non-zero, in addition to having the AB and Berry phase factors, the magnitude of the exchange constant can also be renormalized by an effective-mass correction. These effects may be relevant for the WC and its proximate phases recently observed in tetra- and penta-layer rhombohedral graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
6 pages; comments welcome!