CMP Journal 2025-06-10
Statistics
Nature: 1
Nature Nanotechnology: 2
Physical Review Letters: 7
Physical Review X: 2
arXiv: 97
Nature
Silicate clouds and a circumplanetary disk in the YSES-1 exoplanet system
Original Paper | Astrophysical disks | 2025-06-09 20:00 EDT
K. K. W. Hoch, M. Rowland, S. Petrus, E. Nasedkin, C. Ingebretsen, J. Kammerer, M. Perrin, V. D’Orazi, W. O. Balmer, T. Barman, M. Bonnefoy, G. Chauvin, C. Chen, R. J. De Rosa, J. Girard, E. Gonzales, M. Kenworthy, Q. M. Konopacky, B. Macintosh, S. E. Moran, C. V. Morley, P. Palma-Bifani, L. Pueyo, B. Ren, E. Rickman, J.-B. Ruffio, C. A. Theissen, K. Ward-Duong, Y. Zhang
Young exoplanets provide a critical link between understanding planet formation and atmospheric evolution1. Direct imaging spectroscopy allows us to infer the properties of young, wide orbit, giant planets with high signal-to-noise. This allows us to compare this young population to exoplanets characterized with transmission spectroscopy, which has indirectly revealed the presence of clouds2-4, photochemistry5, and a diversity of atmospheric compositions6-7. Direct detections have also been made for brown dwarfs8-9, but direct studies of young giant planets in the mid-infrared were not possible prior to JWST10. With two exoplanets around a solar type star, the YSES-1 system is an ideal laboratory for studying this early phase of exoplanet evolution. We report the first direct observations of silicate clouds in the atmosphere of the exoplanet YSES-1 c through its 9-11 µm absorption feature, and the first circumplanetary disk silicate emission around its sibling planet, YSES-1 b. The clouds of YSES-1 c are composed of either amorphous iron-enriched pyroxene or a combination of amorphous MgSiO3 and Mg2SiO4, with particle sizes of ≤0.1 μm at 1 millibar of pressure. We attribute the emission from the disk around YSES-1 b to be from submicron olivine dust grains, which may have formed through collisions of planet-forming bodies in the disk.
Astrophysical disks, Exoplanets
Nature Nanotechnology
Atomic manipulation of the emergent quasi-2D superconductivity and pair density wave in a kagome metal
Original Paper | Scanning probe microscopy | 2025-06-09 20:00 EDT
Xianghe Han, Hui Chen, Hengxin Tan, Zhongyi Cao, Zihao Huang, Yuhan Ye, Zhen Zhao, Chengmin Shen, Haitao Yang, Binghai Yan, Ziqiang Wang, Hong-Jun Gao
The unconventional charge density wave (CDW) order in layered kagome lattice superconductors AV3Sb5 (A = K, Cs or Rb) triggers the emergence of novel quantum states such as time-reversal symmetry breaking and electronic liquid crystal states. However, atomic-scale manipulation and control of such phases remains elusive. Here we observe the emergent superconductivity and a primary pair density wave at the 2 × 2 Cs reconstructed surface of CsV3Sb5 by means of low-temperature scanning tunnelling microscopy/spectroscopy paired with density functional theory calculations. This quasi-two-dimensional kagome superconducting state with a critical temperature of ~5.4 K is intertwined with the bulk CDW order and exhibits a unique vortex core spectrum and a 4 × 4 pair density wave modulation of the superconducting gap. The emergent phenomena happen at a π-phase-shift dislocation in the periodicity of the CDW along the stacking direction if the 2 × 2 Cs superstructures are out of phase with the bulk CDW. Furthermore, we switched on and off the quasi-two-dimensional superconductivity through tip-assisted atomic manipulation of the 2 × 2 Cs superstructure. Thus, control of the surface reconstruction permits the creation, manipulation and control of quantum many-body states at antiphase boundaries in kagome lattice superconductors and, potentially, in other correlated materials.
Scanning probe microscopy, Superconducting properties and materials
Modulation of SARS-CoV-2 spike binding to ACE2 through conformational selection
Original Paper | Biological physics | 2025-06-09 20:00 EDT
Prithwidip Saha, Ignacio Fernandez, Fidan Sumbul, Claire Valotteau, Dorota Kostrz, Annalisa Meola, Eduard Baquero, Arvind Sharma, James R. Portman, François Stransky, Thomas Boudier, Pablo Guardado-Calvo, Charlie Gosse, Terence Strick, Felix A. Rey, Felix Rico
The first step of SARS-CoV-2 infection involves the interaction between the viral trimeric spike protein (S) and the host angiotensin-converting enzyme 2 (ACE2). The receptor-binding domain (RBD) of S adopts two conformations: open and closed, respectively accessible and inaccessible to ACE2. Although these changes surely affect ACE2 binding, a quantitative description of the underlying mechanisms has remained elusive. Here we visualize RBD opening and closing using high-speed atomic force microscopy, gaining access to the corresponding transition rates. We also probe the S/ACE2 interaction at the ensemble level with biolayer interferometry and at the single-molecule level with atomic force microscopy and magnetic tweezers, evidencing that RBD dynamics hinder ACE2 binding but have no effect on unbinding. The resulting modulation is quantitatively predicted by a conformational selection model in which each S protomer behaves independently. Our work thus reveals a molecular mechanism by which RBD accessibility and binding strength can be tuned separately, providing hints to better understand the joint evolution of immune evasion and infectivity.
Biological physics, SARS-CoV-2
Physical Review Letters
Ultrabright Entanglement Based Quantum Key Distribution over a 404 km Optical Fiber
Research article | Optical quantum information processing | 2025-06-09 06:00 EDT
Shi-Chang Zhuang, Bo Li, Ming-Yang Zheng, Yi-Xi Zeng, Hui-Nan Wu, Guang-Bing Li, Quan Yao, Xiu-Ping Xie, Yu-Huai Li, Hao Qin, Li-Xing You, Feihu Xu, Juan Yin, Yuan Cao, Qiang Zhang, Cheng-Zhi Peng, and Jian-Wei Pan
Entangled photons are crucial resources for quantum information processing. Here, we present an ultrabright polarization-entangled photon source based on a periodically poled lithium niobate waveguide designed for practical quantum communication networks. Using a 780 nm pump laser, the source achieves a pair generation rate of $2.4\times{}{10}^{10}\text{ }\text{ }\mathrm{pairs}/\mathrm{s}/\mathrm{mW}$. Remarkably, the entangled photons are bright enough to be detected by a power meter, reaching a power of 17.9 nW under a pump power of 3.2 mW. We demonstrate the practicality of the source by conducting quantum key distribution experiments over long-distance fiber links. Wavelength-division multiplexing was employed to enhance the key generation, and nonlocal dispersion compensation was implemented to ensure precise timing coincidence measurements across a broad spectral range. By utilizing nine pairs of wavelength channels, the system achieved the applicable secure key rates of up to $440.80\text{ }\text{ }\mathrm{bits}/\mathrm{s}$ over 200 km with a 62 dB loss and extended the maximum secure key generation distance to 404 km. These results demonstrate the potential of wavelength-multiplexed polarization-entangled photon sources for high-speed, long-distance quantum communication, positioning them as key components for future large-scale quantum networks.
Phys. Rev. Lett. 134, 230801 (2025)
Optical quantum information processing, Quantum communication, Quantum cryptography, Quantum entanglement, Quantum networks
Evidence of Coherent Elastic Neutrino-Nucleus Scattering with COHERENT’s Germanium Array
Research article | Electroweak interaction | 2025-06-09 06:00 EDT
S. Adamski et al. (The COHERENT Collaboration)
We report the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) on natural germanium, measured at the Spallation Neutron Source at Oak Ridge National Laboratory. The Ge-Mini detector of the COHERENT collaboration employs large-mass, low-noise, high-purity germanium spectrometers, enabling excellent energy resolution, and an analysis threshold of 1.5 keV electron-equivalent ionization energy. We observe an on-beam excess of ${20.6}_{- 6.3}^{+7.1}$ counts with a total exposure of 10.22 GWhkg, and we reject the no-CEvNS hypothesis with $3.9\sigma $ significance. The result agrees with the predicted standard model of particle physics signal rate within $2\sigma $.
Phys. Rev. Lett. 134, 231801 (2025)
Electroweak interaction, Neutrino interactions, Nucleus-neutrino interactions, Semiconductors, Neutrino detection
Dual View of the ${\mathrm{Z}}_{2}$-Gauged XY Model in 3D
Research article | Fractionalization | 2025-06-09 06:00 EDT
Piers Coleman, Anatoly Kuklov, and Alexei Tsvelik
The ${Z}_{2}$-gauged XY model is of long-standing interest both in the context of nematic order, and the study of fractionalization and superconductivity. This Letter presents heuristic arguments that no deconfinement of the XY field occurs in this model and presents results of a large-scale Monte Carlo simulations on a cubic lattice that are consistent with this conclusion. The correlation radius determining the confinement is found to be growing rapidly as a function of the parameters in the phase featuring the nematic order. Thus, mesoscopic properties of the system can mimic deconfinement with high accuracy in some part of the phase diagram.
Phys. Rev. Lett. 134, 236001 (2025)
Fractionalization, Superconductivity
Structure and Strain Field of Surface Dislocations on Gold Determined by Surface X-Ray Diffraction
Research article | Disclinations & dislocations | 2025-06-09 06:00 EDT
Vincent Repain, Julien Durinck, Yves Garreau, Alessandro Coati, Yann Girard, Sylvie Rousset, Christophe Coupeau, and Amandine Bellec
Au(111) with its famous surface reconstruction has led to many studies, but its subsurface structure has never been determined. Here, we study the Au(677) surface which is a vicinal of Au(111) with steps and surface reconstruction, showing an array of surface dislocations. By using surface x-ray diffraction and atomistic simulations, we are able to quantitatively determine the complete structure and the strain fields associated with the surface reconstruction described in terms of surface dislocations, especially a stair-rod dislocation lying parallel to the surface step. The stair-rod dislocation strain field adds up to the one due to the step dipole, explaining the extraordinary regularity of the step array. We can also give new insights on the strain field associated with the Au(111) surface discommensuration lines ($22\times{}\sqrt{3}$ reconstruction) and find that it penetrates deeply into the bulk, in contrast with commonly used surface reconstruction models.
Phys. Rev. Lett. 134, 236201 (2025)
Disclinations & dislocations, Strain, Surface reconstruction, Surfaces, Molecular dynamics, Surface scattering
Moments of Entropy Production in Dissipative Devices
Research article | Fluctuation theorems | 2025-06-09 06:00 EDT
Jean-Charles Delvenne and Léopold Van Brandt
We characterize the possible moments of entropy production for overdamped stationary Markov processes. We find a general formulation of the problem, and derive a new necessary condition relating the second and third moments. We determine all possible first, second, and third moments of entropy production for a white noise process. As a consequence, we obtain a lower bound for the skewness of the current fluctuations in dissipative devices such as transistors, thereby demonstrating that the Gaussianity assumption widely used, e.g., in electronic engineering is thermodynamically inconsistent.
Phys. Rev. Lett. 134, 237101 (2025)
Fluctuation theorems, Fluctuations & noise, Noise, Stochastic processes, Stochastic thermodynamics, Markovian processes
Fully Independent Response in Disordered Solids
Research article | Elastic modulus | 2025-06-09 06:00 EDT
Mengjie Zu, Aayush Desai, and Carl P. Goodrich
Unlike in crystals, it is difficult to trace emergent material properties of amorphous solids to their underlying structure. Nevertheless, one can tune features of a disordered spring network, ranging from bulk elastic constants to specific allosteric responses, through highly precise alterations of the structure. This has been understood through the notion of independent bond-level response—the observation that, in many cases, different springs have different effects on different properties. While this idea has motivated inverse design in numerous contexts, it has not been formalized and quantified in a general context that not just informs but enables and predicts inverse design. Here, we show how to quantify independent response by linearizing the simultaneous change in multiple emergent features, and introduce the much stronger notion of fully independent response. Remarkably, we find that the mechanical properties of disordered solids are always fully independent across a wide array of scenarios, regardless of the target features, tunable parameters, system size, dimensionality, and class of interactions. Furthermore, our formulation quantifies the susceptibility of features to parameter changes, which is correlated with the maximum linear tunability. We also demonstrate the implications for multifeature inverse design beyond the linear regime. These results formalize our understanding of a key fundamental difference between ordered and disordered solids while also creating a practical tool to both understand and perform inverse design.
Phys. Rev. Lett. 134, 238201 (2025)
Elastic modulus, Inverse problems, Jamming, Learning, Self-assembly, Disordered systems, Glassy systems, Granular materials
Nonlinear Spontaneous Flow Instability in Active Nematics
Research article | Emergence of patterns | 2025-06-09 06:00 EDT
Ido Lavi, Ricard Alert, Jean-François Joanny, and Jaume Casademunt
Active nematics exhibit spontaneous flows through a well-known linear instability of the uniformly aligned quiescent state. Here, we show that even a linearly stable uniform state can experience a nonlinear instability, resulting in a discontinuous transition to spontaneous flows. In this case, quiescent and flowing states may coexist. Through a weakly nonlinear analysis and a numerical study, we trace the bifurcation diagram of striped patterns and show that the underlying pitchfork bifurcation switches from supercritical (continuous) to subcritical (discontinuous) by varying the flow-alignment parameter. We predict that the discontinuous spontaneous flow transition occurs for a wide range of parameters, including systems of contractile flow-aligning rods. Our predictions are relevant to active nematic turbulence and can potentially be tested in experiments on either cell layers or active cytoskeletal suspensions.
Phys. Rev. Lett. 134, 238301 (2025)
Emergence of patterns, Flow instability, Active liquid films, Active nematics
Physical Review X
Machine Learning to Select Experiments Driven by Fundamental Science and Applications for Targeted Nuclear Data Improvement
Research article | Fission | 2025-06-09 06:00 EDT
D. Neudecker, T. E. Cutler, M. Devlin, P. Brain, N. Gibson, M. J. Grosskopf, M. W. Herman, J. Hutchinson, T. Kawano, A. Khatiwada, N. Kleedtke, E. Leal-Cidoncha, R. C. Little, A. E. Lovell, A. Stamatopoulos, E. C. Thompson, S. A. Vander Wiel, and E. Williamson (PARADIGM Collaboration)
Machine learning identifies the optimal mix of fundamental science and applied experiments to refine nuclear data for plutonium-239, dramatically accelerating progress in basic science and nuclear technology.
Phys. Rev. X 15, 021086 (2025)
Fission, Models & methods for nuclear reactions, Neutron physics, Nuclear engineering, Nuclear reactions, Patterns in complex systems, 150 ≤ A ≤ 189, 190 ≤ A ≤ 219, 20 ≤ A ≤ 38, 39 ≤ A ≤ 58, 59 ≤ A ≤ 89, 6 ≤ A ≤ 19, 90 ≤ A ≤ 149, A ≥ 220, Artificial intelligence, Machine learning, Neutron capture, Neutron scattering, Nuclear data analysis & compilation
Nonlocal Moments and Mott Semimetal in the Chern Bands of Twisted Bilayer Graphene
Research article | Charge order | 2025-06-09 06:00 EDT
Patrick J. Ledwith, Junkai Dong (董焌锴), Ashvin Vishwanath, and Eslam Khalaf
A new framework explains how twisted bilayer graphene hosts both localized charge and delocalized states, revealing a semimetallic thermal state at neutrality and a spectrally imbalanced Mott state at other charge fillings.
Phys. Rev. X 15, 021087 (2025)
Charge order, Chern insulators, Doublon, Exotic phases of matter, Flat bands, Geometric & topological phases, Magnetic order, Methods in magnetism, Nematic order, Topological materials, Topological phases of matter, Twistronics, Mott insulators, Twisted bilayer graphene, Diagrammatic methods, Electron-correlation calculations, Finite temperature field theory, Wannier function methods
arXiv
On the role of secondary electrons in the color change of high-dose X-ray irradiated topaz
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
G. S. Elettivo, M. Ferraro, R. Filosa, A. Nicolino, B. Marmiroli, A. Turchet, R. G. Agostino
Owing to its high brightness, synchrotron light allows for investigating with extreme precision the physical properties of matter. The irradiation with high-dose X-ray beams may also lead to modification of the latter, thus allowing for material processing. Here we investigate the color change of topaz irradiated with synchrotron light, shedding light on the role played by secondary electrons in the formation of color centers. As a matter of fact, treatments of natural topaz to induce its color change are largely used in the jewelry industry. Nevertheless, the physical mechanisms behind the topaz’s color change have not yet been fully understood. To date, it has been shown that the combined action of high-energy beam irradiation (either electrons, neutrons, or {\gamma}-rays) and thermal annealing permits to provide colorless natural topaz with an artificial blue color, which is largely appealed in the gem market. Here we demonstrate that it is possible to irreversibly provide natural topaz with a blue color even by exploiting lower energy beams, such as X-rays, provided that enough dose is absorbed, thus paving the way for developing novel protocols for making artificially blue topazes.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Machine Learning-Assisted Analysis of Combustion and Ignition in As-milled and Annealed Al/Zr Composite Powders
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Michael R. Flickinger, Sreenivas Raguraman, Amee L. Polk, Colin Goodman, Megan Bokhoor, Rami Knio, Michael Kruppa, Mark A. Foster, Timothy P. Weihs
Micron-scale metal-based composite powders are promising for energetic applications due to their tailored ignition and combustion properties. In particular, ball-milled Al/Zr composites exhibit lower ignition thresholds than pure aluminum, driven by exothermic intermetallic formation reactions and have demonstrated enhanced combustion properties. However, the extent to which this heat release governs ignition and combustion remains unclear, especially when progressively removed through annealing. To systematically investigate this effect, we synthesized Al/Zr powders (3Al:Zr, Al:Zr, and Al:3Zr at%) via ball milling, annealed them in argon up to 1000 C to partially complete the formation reactions, and characterized their ignition and combustion behavior. Ignition thresholds were measured using a hot wire method across different environments, while high-speed hyperspectral imaging tracked single-particle burn durations and temperatures. A convolutional neural network (CNN)-based method was developed to quantify the frequency of microexplosions. Results show that annealing - and thus reducing available reaction heat - increases ignition thresholds, most significantly for Al-rich compositions. In contrast, Zr-rich powders exhibit little change in ignition thresholds due to oxidation aiding ignition. Despite removing the available heat that drives ignition, average combustion temperatures range from 2400-3000 K and increased with annealing for Al- and Zr-rich powders. Average maximum temperatures are 100 to 400 K higher. The frequency of microexplosions remains high (>46%) and increases with annealing for all but the Al-rich powders. These findings suggest that while homogeneous Al/Zr powders (e.g., atomized) may exhibit higher ignition thresholds, they can achieve comparable combustion performance once ignited.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
20 pages, 14 figures, 4 tables
Rheological Origin of Aging
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Most materials of practical applications age, and their properties change with time. The aging of materials is reflected in their mechanical responses to external stress and strain, which exhibit ubiquity in the form of logarithms and power laws, respectively. Such responses are usually described using complicated phenomenological models, including fractional viscoelastic models, but they lack physical insights. In this Letter, we postulate a linear time-varying rheological property whose constitutive relations are motivated from thermodynamic principles and experimental observations of the stick-slip-induced friction. The property satisfyingly explains the logarithmic relaxation and the three stages of universal creep behavior. Consequently, the fractional Maxwell model and the Mittag-Leffler function gain physical interpretation. Lastly, we show that viscosity emerges as a special case of the proposed property.
Soft Condensed Matter (cond-mat.soft)
13 pages, 3 figures
A high -quality and -throughput colloidal lithography by mechanical assembly and ice-based transfer
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Sivan Tzadka, Abed Al Kader Yassin, Esti Toledo, Jatin Jawhir Pandit, Angel Porgador, Mark Schvartzman
Colloidal lithography has emerged as a promising alternative to conventional nanofabrication techniques, offering the ability to create nanoscale patterns in a cost-effective and scalable manner. However, it has been so far limited by defects such as empty areas or multilayered regions, hindering its application. We introduce a novel “ice-assisted transfer” technique that combines rubbing-based particle assembly on elastomer substrates with ice-mediated transfer to achieve defect-free, high-quality polycrystalline particle monolayers. This approach eliminates foreign material contamination and enables precise control of particle arrangement and density. By optimizing process parameters, including surfactant concentration and water film thickness, we minimized defects and demonstrated the versatility of this method in fabricating functional nanoscale structures. We highlighted the benefits of this process through two applications: (1) antireflective “moth-eye” coatings, which achieved near-zero reflection in the mid-infrared spectrum due to improved particle monolayer quality; and (2) nanostructured surfaces for ligand-free T-cell activation, whose topography enhanced cell activation, showcasing potential for immunotherapy applications. The process achieves rapid, cost-efficient patterning without requiring specialized equipment, making it suitable for diverse fields requiring scalable nanostructuring. This work represents a significant advancement in colloidal lithography, addressing critical challenges and unlocking its potential for practical applications in optics, biotechnology, and beyond.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Anomalous Shear Stress Growth During Relaxation of a Soft Glass
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
We show experimentally that multiple soft glassy fluids are capable of storing directional rheological signatures from past shear history, evidenced during stress growth and overall nonmonotonic stress relaxation after small steps in strain. We illustrate theoretically that these responses can be reproduced without requiring thixotropy or shear-banding, which are typically implicated in time-dependent rheological complexities, but by using a simple elastoplastic rheological model with power-law yielding (EP-PLY) that incorporates a distribution of local strain states. Using insight from the model, we suggest a mechanism for the experimentally observed stress increase to be driven by residual anisotropy in strain states that are relaxed at different rates. We demonstrate that these effects persist even after material is stressed beyond the yield stress, indicating that past deformation may have more influence than previously thought.
Soft Condensed Matter (cond-mat.soft)
Momentum-space Metric Tensor from Nonadiabatic Evolution of Bloch Electrons
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
We reveal a fundamental geometric structure of momentum space arising from the nonadiabatic evolution of Bloch electrons. By extending semiclassical wave packet theory to incorporate nonadiabatic effects, we introduce a momentum-space metric tensor – the nonadiabatic metric. This metric gives rise to two velocity corrections, dubbed geometric and geodesic velocities, providing a unified and intuitive framework for understanding nonlinear and nonadiabatic transport phenomena beyond Berry phase effects. Furthermore, we show that the nonadiabatic metric endows momentum space with a curved geometry, recasting wave packet dynamics as forced geodesic motion. In this picture, the metric defines distances, the Berry connection acts as a gauge potential, band dispersion serves as a scalar potential, and the toroidal topology of the Brillouin zone imposes periodic boundary conditions. When the nonadiabatic metric is constant, it reduces to an effective mass, allowing electrons to behave as massive particles in flat bands. In a flat Chern band with harmonic attractive interactions, the two-body wave functions mirror the Landau-level wave functions on a torus.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Relativity and Quantum Cosmology (gr-qc)
8 pages, 3 figures; comments are welcome
Alignment and anisotropy of stresses in disordered granular media
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Aashish K. Gupta, Christopher Ness, Sina Haeri
Characterizing the degeneracy of local stress states is a central challenge in obtaining the complete statistical mechanics of disordered media. Here, we introduce a minimal force-balance model for isolated granular clusters to probe the structure of the stress space through principal stress orientation and stress anisotropy. We further show that when complemented by physically motivated pairwise constraints, the model produces predictions for the stress alignment in packings of repulsive hard spheres. We compare these predictions against simulation data for grains in hopper and simple shear flows, finding quantitative agreement. This demonstrates the promise of modeling bulk athermal disordered systems through the combinatorics of few primitive geometric motifs.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Dynamical thermalization, Rayleigh-Jeans condensate, vortexes and wave collapse in quantum chaos fibers and fluid of light
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-10 20:00 EDT
Leonardo Ermann, Alexei D. Chepelianskii, Dima L. Shepelyansky
We study analytically and numerically the time evolution of a nonlinear field described by the nonlinear Schrödinger equation in a chaotic $ D$ -shape billiard. In absence of nonlinearity the system has standard properties of quantum chaos. This model describes a longitudinal light propagation in a multimode D-shape optical fiber and also those in a Kerr nonlinear medium of atomic vapor. We show that, above a certain chaos border of nonlinearity, chaos leads to dynamical thermalization with the Rayleigh-Jeans thermal distribution and the formation of the Rayleigh-Jeans condensate in a vicinity of the ground state accumulating in it about 80-90% of total probability. Certain similarities of this phenomenon with the Fröhlich condensate are discussed. Below the chaos border the dynamics is quasi-integrable corresponding to the Kolmogorov-Arnold-Moser integrability. The evolution to the thermal state is characterized by an unusual entropy time dependence with an increase on short times and later significant decrease when approaching to the steady-state. This behavior is opposite to the Boltzmann H-theorem and is attributed to the formation of Rayleigh-Jeans condensate and presence of two integrals of motion, energy and norm. At a strong focusing nonlinearity we show that the wave collapse can take place even at sufficiently high positive energy being very different from the open space case. Finally for the defocusing case we establish the superfluid regime for vortex dynamics at strong nonlinearity.
System parameters for optical fiber experimental studies of these effects are also discussed.
Statistical Mechanics (cond-mat.stat-mech), Dynamical Systems (math.DS), Chaotic Dynamics (nlin.CD), Optics (physics.optics)
35 pages, 33 figures
Orbital Hall conductivity and orbital diffusion length of Vanadium thin films by Hanle magnetoresistance
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
M. Xochitl Aguilar-Pujol, Isabel C. Arango, Eoin Dolan, Marco Gobbi, Luis E. Hueso, Fèlix Casanova
In spintronics, the spin Hall effect has been widely used to generate and detect spin currents in materials with strong spin-orbit coupling such as Pt and Ta. Recently, its orbital counterpart has drawn attention as a new tool to generate and detect orbital currents and thus investigate orbital transport parameters. In this study, we investigate vanadium (V), a $ 3d$ transition metal with weak spin-orbit coupling but with a theoretically large orbital Hall conductivity. We measure a large Hanle magnetoresistance in V thin films with a magnitude comparable to that of heavy metals and at least one order of magnitude higher than the spin Hall magnetoresistance observed in a Y$ _3$ Fe$ _5$ O$ _{12}$ /V bilayer, pointing to the orbital Hall origin of the effect. A fit of the magnetic-field dependence and thickness dependence of the Hanle magnetoresistance to the standard diffusion model allows us to quantify the orbital diffusion length (2 nm) and the orbital Hall conductivity (78 ($ \hbar/2e$ ) $ \Omega^{-1}$ cm$ ^{-1}$ ) of V. The obtained orbital Hall conductivity is two orders of magnitude smaller than theoretical calculations of the intrinsic value, suggesting there is an important role of disorder.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 5 figures, Supplemental Material
Intrinsic defects explain n-type conductivity in CrSBr
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Timur Biktagirov, Wolf Gero Schmidt, Karl Jakob Schiller, Michele Capra, Jonah Elias Nitschke, Lasse Sternemann, Anna Isaeva, Mirko Cinchetti
Understanding and controlling native defects is essential for unlocking the full potential of two-dimensional magnetic semiconductors. Here, angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations are used to explore the electronic properties of bulk CrSBr. ARPES measurements reveal clear signatures of conduction band filling in as-grown crystals, indicative of unintentional doping. An analysis of intrinsic defects based on density functional theory (DFT) identifies chromium interstitials ($ Cr_i$ ) stabilized between CrSBr layers as the most favorable shallow donors. Bromine-on-sulfur antisites ($ Br_S$ ) and bromine vacancies ($ V_{Br}$ ) are also found to act as potential donors, albeit with deeper ionization energies. Our results shed light on the origin of unintentional $ \textit{n}$ -type doping of CrSBr and pave the way for new strategies for defect control and electronic property tuning in this van der Waals magnet.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Acoustic-Driven Surface Cleaning with Millimeter-Sized Bubbles at Translational Resonance
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Yan Jun Lin, Zhengyang Liu, Sunghwan Jung
Traditional surface cleaning methods often suffer from drawbacks such as chemical harshness, potential for surface damage, and high energy consumption. This study investigates an alternative approach: acoustic-driven surface cleaning using millimeter-sized bubbles excited at low, sub-cavitation frequencies. We identify and characterize a distinct translational resonance of these bubbles, occurring at significantly lower frequencies (e.g., 50 Hz for 1.3 mm diameter bubbles) than the Minnaert resonance for a bubble of the same size. Experiments reveal that at this translational resonance, stationary bubbles exhibit amplified lateral swaying, while bubbles sliding on an inclined surface display pronounced “stop-and-go” dynamics. The theoretical model treats the bubble as a forced, damped harmonic oscillator, where surface tension provides the restoring force and the inertia is dominated by the hydrodynamic added mass of the surrounding fluid. It accurately predicts the observed resonant frequency scaling with bubble size ($ \propto R_0^{-3/2}$ ). Cleaning efficacy, assessed using protein-based artificial soil on glass slides, was improved by approximately 90% when bubbles were driven at their translational resonant frequency compared to off-resonant frequencies or non-acoustic conditions. These findings demonstrate that leveraging translational resonance enhances bubble-induced shear and agitation, offering an effective and sustainable mechanism for surface cleaning.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
22 pages, 6 figures, presented at the 78th Annual Meeting of the APS Division of Fluid Dynamics
Imaging 3D polarization dynamics via deep learning 4D-STEM
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Jinho Byun, Keeyong Lee, Myoungho Jeong, Eunha Lee, Jeongil Bang, Haeryong Kim, Geun Ho Gu, Sang Ho Oh
Recent advances in ferroelectrics highlight the role of three-dimensional (3D) polar entities in forming topological polar textures and generating giant electromechanical responses, during polarization rotation. However, current electron microscopy methods lack the depth resolution to resolve the polarization component along the electron beam direction, which restricts full characterization. Here, we present a deep learning framework combined with four-dimensional scanning transmission electron microscopy to reconstruct 3D polarization maps in Ba0.5Sr0.5TiO3 thin-film capacitors with picometer-level accuracy under applied electric fields. Our approach enables observation of polar nanodomains consistent with the polar slush model and shows that switching occurs through coordinated vector rotation toward <111> energy minima, rather than magnitude changes. Furthermore, regions with higher topological density exhibit smaller polarization variation when the electric field changes, indicating topological protection. Our work reveals the value of 3D polarization mapping in elucidating complex nanoscale polar phenomena, with broad implications for emergent ferroelectrics.
Materials Science (cond-mat.mtrl-sci)
30 pages, 14 figures
Emergent Viscous Hydrodynamics From a Single Quantum Particle
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-10 20:00 EDT
Zhi-Li Zhou, Mauricio Hippert, Nicki Mullins, Jorge Noronha
We investigate an explicit example of how spatial decoherence can lead to hydrodynamic behavior in the late-time, long-wavelength regime of open quantum systems. We focus on the case of a single non-relativistic quantum particle linearly coupled to a thermal bath of noninteracting harmonic oscillators at temperature $ T$ , a la Caldeira and Leggett. Taking advantage of decoherence in the position representation, we expand the reduced density matrix in powers of the off-diagonal spatial components, so that high-order terms are suppressed at late times. Truncating the resulting power series at second order leads to a set of dissipative transient hydrodynamic equations similar to the non-relativistic limit of equations widely used in simulations of the quark-gluon plasma formed in ultrarelativistic heavy-ion collisions. Transport coefficients are directly determined by the damping constant $ \gamma$ , which quantifies the influence of the environment. The asymptotic limit of our hydrodynamic equations reduces to the celebrated Navier-Stokes equations for a compressible fluid in the presence of a drag force. Our results shed new light on the onset of hydrodynamic behavior in quantum systems with few degrees of freedom.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Nuclear Theory (nucl-th), Quantum Physics (quant-ph)
29 pages, 3 figures
Lithography defined semiconductor moires with anomalous in-gap quantum Hall states
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Wei Pan, D. Bruce Burckel, Catalin D. Spataru, Keshab R. Sapkota, Aaron J. Muhowski, Samuel D. Hawkins, John F. Klem, Layla S. Smith, Doyle A. Temple, Zachery A. Enderson, Zhigang Jiang, Komalavalli Thirunavukkuarasu, Li Xiang, Mykhaylo Ozerov, Dmitry Smirnov, Chang Niu, Peide D. Ye, Praveen Pai, Fan Zhang
Quantum materials and phenomena have attracted great interest for their potential applications in next-generation microelectronics and quantum-information technologies. In one especially interesting class of quantum materials, moire superlattices (MSL) formed by twisted bilayers of 2D materials, a wide range of novel phenomena are observed. However, there exist daunting challenges such as reproducibility and scalability of utilizing 2D MSLs for microelectronics and quantum technologies due to their exfoliate-tear-stack method. Here, we propose lithography defined semiconductor moires superlattices, in which three fundamental parameters, electron-electron interaction, spin-orbit coupling, and band topology, are designable. We experimentally investigate quantum transport properties in a moire specimen made in an InAs quantum well. Strong anomalous in-gap states are observed within the same integer quantum Hall state. Our work opens up new horizons for studying 2D quantum-materials phenomena in semiconductors featuring superior industry-level quality and state-of-the-art technologies, and they may potentially enable new quantum information and microelectronics technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
published by Nano Letters
Enhancing z spin generation in trivial spin Hall materials for scalable, energy-efficient, field-free, complete spin-orbit torque switching applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Despite the remarkable efforts in the past two decades, it has remained a major challenge to achieve switching of perpendicularly magnetized spin-orbit torque devices in a scalable, energy-efficient, field-free, integration-friendly, and complete manner. Here, we report giant enhancement of z spin generation in low-resistivity spin Hall metal/FeCoB devices by alloying the spin Hall metal Pt with Ti and by electric asymmetry engineering. The dampinglike spin torques of z spins and y spins are enhanced by 6 and 3 times relative to that of conventional Pt/FeCoB and enable complete, record-low-power, deterministic switching of FeCoB devices with strong perpendicular magnetic anisotropy and high coercivity. The Pt75Ti25/FeCoB heterostructure also exhibits relatively low resistivity, wafer-scale uniform sputter-deposition on silicon oxide, good compatibility with magnetic tunnel junctions, and excellent thermal stability of exceeding 400 C. These results unambiguously establish the Pt75Ti25/FeCoB as the most compelling candidate for solving the bottleneck of scalable, energy-efficient, field-free, integration-friendly, and complete spin-orbit torque switching technologies. This work also provides a universal strategy for developing high-performance generators of z spin current and will stimulate the exploration of exotic spin currents by alloying trivial spin Hall materials.
Materials Science (cond-mat.mtrl-sci)
Mobility edges and fractal states in quasiperiodic Gross-Pitaevskii chains
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-10 20:00 EDT
Oleg I. Utesov, Yeongjun Kim, Sergej Flach
We explore properties of a Gross-Pitaevskii chain subject to an incommensurate periodic potential, i.e., a nonlinear Aubry-Andre model. We show that the condensate crucially impacts the properties of the elementary excitations. In contrast to the conventional linear Aubry-Andre model, the boundary between localized and extended states (mobility edge) exhibits nontrivial branching. For instance, in the high-density regime, tongues of extended phases at intermediate energies penetrate the domain of localized states. In the low-density case, the situation is opposite, and tongues of localized phases emerge. Moreover, intermediate critical (fractal) states are observed. The low-energy phonon part of the spectrum is robust against the incommensurate potential. Our study shows that accounting for interactions, already at the classical level, lead to highly nontrivial behavior of the elementary excitation spectrum.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
11 pages, 7 figures
Atomistic Simulations of Cation Distribution and Defect Effects on the Performance of Substituted Ferrites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Jiahao Li, Kusma Kumari Cheepurupalli, Niall J. English, Sateesh Bandaru, Xuefeng Zhang
This study investigates Mn-Zn ferrites (nominal composition \ce{Mn_{0.5}Zn_{0.5}Fe2O4}, MZF) substituted with tetravalent (\ce{Si^{4+}}), trivalent (\ce{Co^{3+}}), and divalent (\ce{Ca^{2+}}, \ce{Mg^{2+}}, \ce{Sn^{2+}}) ions. We comprehensively analyze how substitutions at specific tetrahedral and octahedral crystallographic sites modulate the spinel lattice’s structural stability, electronic band structure, magnetic anisotropy, and electrical conductivity. Density functional theory (DFT) combined with Boltzmann transport theory is employed to probe the thermoelectric and phonon transport properties of pristine and doped MZF systems. Formation energy calculations indicate that substitutions with \ce{Si^{4+}}, \ce{Ca^{2+}}, and \ce{Mg^{2+}} enhance the thermodynamic stability of MZF, while \ce{Co^{3+}} and \ce{Sn^{2+}} substitutions exhibit slightly higher formation energies, indicating relatively lower stability. Electronic structure analyses confirm all substituted variants retain a finite band gap, preserving their semiconducting nature. Magnetic anisotropy energy (MAE) calculations reveal that ferrites with mixed octahedral/tetrahedral substitutions display a narrower MAE distribution, signifying more uniform magnetic anisotropy. Thermoelectric property analysis at 300 K demonstrates that multivalent ion doping at either crystallographic site reduces electrical conductivity ($ \sigma$ ) while concurrently enhancing the Seebeck coefficient ($ S$ ). This inverse correlation highlights a doping-induced trade-off, likely driven by increased carrier scattering at defect sites and modifications to the electronic density of states near the Fermi level.
Materials Science (cond-mat.mtrl-sci)
Quantization and quantum oscillations of the sublattice charge order in Dirac insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Arindam Tarafdar, Tigran A. Sedrakyan
We report the quantization, quantum oscillations, and singular behavior of sublattice symmetry-breaking sublattice charge order (SCO) in two-dimensional Dirac insulators at charge neutrality under perpendicular magnetic fields $ B$ . SCO is induced by staggered sublattice potentials, such as those originating from substrates, strains, hydrogenation, and chemical doping. In small non-quantizing magnetic fields that result in less than a flux quantum threading the system, and small sublattice symmetry breaking potentials, SCO exhibits perturbative singular magnetic field dependence, $ \sim |B|$ , originating from hopping between neighboring sites of the same sublattice. At intermediate magnetic fields, when the cyclotron gap between the zeroth Landau level and the first Landau level, $ \omega_c$ , is smaller than the sublattice potential, $ \omega_c\lesssim \Delta$ , SCO shows $ \textit{universally}$ quantized plateaus owing to discrete Landau-level degeneracy. As the magnetic flux increases by one flux quantum, one electron (per spin) is transferred from the sublattice with a higher chemical potential to the sublattice with a lower chemical potential. One electron transfer between sublattices per flux quantum results from the sublattice polarization of the zeroth Landau level in gapped Dirac materials, realizing the topological Thouless pump effect. At stronger magnetic fields, $ \omega_c\gtrsim \ \Delta$ , corresponding to integer quantum Hall regimes, SCO displays singularities based on the physics of quantum magneto-oscillations. Our findings suggest new ways to experimentally detect the presence of the energy gap in Dirac materials, irrespective of the gap size.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
17 pages, 13 figures
Intertwined nematic and d-wave superconductive orders in optimally-doped La1.84Sr0.16CuO4
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
Gangfan Chen, Yichi Zhang, Guangyu Xi, Jingyi Shen, Jie Wu
The anisotropy of the superconducting state and superconducting fluctuations in the CuO2 plane is directly related to the superconducting mechanism of copper oxide superconductors and is therefore pivotal for understanding high-temperature superconductivity. Here, we integrated the high-precision angle-resolved resistivity (ARR) measurement with a rotatable in-plane magnetic field to systematically study the angular dependence of superconducting fluctuations in optimally doped La1.84Sr0.16CuO4 (LSCO). By independently controlling the directions of the current and the magnetic field, we are able to isolate the magneto-resistivity contributed by the superconducting vortex motion and distinguish excitations from nematic superconductivity and d-wave superconductive order based on their respective C2 and C4 symmetries. Signatures of two intertwined superconductive orders are also evident in the measured angular dependence of the critical current. A T-B phase diagram of different types of superconducting fluctuations is determined. These findings are closely related to other intriguing phenomena, such as pair density wave and charge density wave.
Superconductivity (cond-mat.supr-con)
Electronic structure and transport in materials with flat bands: 2D materials and quasicrystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Guy Trambly de Laissardière, Somepalli Venkateswarlu, Ahmed Misssaoui, Ghassen Jemaï, Khouloud Chika, Javad Vahedi, Omid Faizy Namarvar, Jean-Pierre Julien, Andreas Honecker, Laurence Magaud, Jouda Jemaa Khabthani, Didier Mayou
In this review, we present our recent works on materials whose common point is the presence of electronic bands of very low dispersion, called “flat bands”, which are always the signature of an electronic confinement. A first part is devoted to the cases where this confinement is due to the long-range geometry of the defect-free structure. We have thus studied periodic approximant structures of quasiperiodic Penrose and octagonal tilings, and twisted bilayers of graphene or transition metal dichalcogenides (TMDs) whose rotation angle between the two layers assumes a special value, called “magic angle”. In these materials, the flat bands correspond to electronic states distributed over a very large number of atoms (several hundreds or even thousands of atoms) and are very sensitive to small structural distortions such as “heterostrain”. Their electronic transport properties cannot be described by usual Bloch-Boltzmann theories, because the interband terms of the velocity operator dominate the intraband terms as far as quantum diffusion is concerned. In twisted bilayer graphene, flat bands can induce a magnetic state and other electron-electron correlation effects. The second part focuses on 2D nanomaterials in the presence of local point defects that cause resonant electronic states (vacancies, adsorbed atoms or molecules). We present studies on monolayer graphene, twisted or Bernal bilayer graphene, carbon nanotubes, monolayer and multilayer black phosphorene, and monolayer TMDs. A recent result is the discovery that the selective functionalization of a Bernal bilayer graphene sublattice leads to a metallic or insulating behavior depending on the functionalized sublattice type. This result, which seems to be confirmed by very recent experimental measurements, suggests that functionalization can be a key parameter to control the electronic properties of two-dimensional materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
review
Polarized electroluminescence with magnetic spectral tuning in van der Waals magnet CrSBr
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Yilei Wang, Shiqi Yang, Leyan Huang, Yuqia Ran, Pingfan Gu, Xinyue Huang, Kenji Watanabe, Takashi Taniguchi, Zuxin Chen, Yu Ye
Polarized wavelength-tunable electroluminescence (EL) represents a critical on-demand functionality for next-generation optoelectronics. While conventional van der Waals (vdW) EL devices offer discrete wavelength switching constrained by fixed emission states, we report a novel platform enabling continuous spectral tuning combined with intrinsically polarized emission. By leveraging exciton-assisted inelastic tunneling in the anisotropic magnet CrSBr, our devices achieve uniform EL with a near unity degree of linear polarization ($ \approx$ 94.3$ %$ ). The strong magneto-electronic coupling in CrSBr facilitates continuous magnetic-field-controlled spectral tuning through spin canting-induced band renormalization. This work establishes vdW magnets as a versatile platform for developing reconfigurable polarized light sources with simultaneous spectral and polarization control.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
What Really Drives Thermopower: Specific Heat or Entropy as the Unifying Principle Across Magnetic, Superconducting, and Nanoscale Systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Morteza Jazandari, Jahanfar Abouie, Daryoosh Vashaee
Thermopower, a key parameter in thermoelectric performance, is often linked to either specific heat or entropy, yet the fundamental quantity that governs it has remained elusive. In this work, we present a unified theoretical framework that identifies entropy per carrier, not specific heat, as the universal driver of thermopower across both closed and open systems. Using thermodynamic identities and the Onsager-Kelvin relation, we show that thermopower is universally proportional to entropy per carrier, while its apparent proportionality to specific heat arises only in systems where the specific heat follows a continuous power-law temperature dependence. To extend this framework to magnetic systems, we derive a general expression for magnon-drag thermopower that holds in both Newtonian (massive, parabolic) and relativistic (massless, linear) magnon regimes. In particular, we reformulate the momentum balance using a relativistic energy-momentum tensor, resolving conceptual inconsistencies in prior models that relied on ill-defined magnon masses in antiferromagnets. Our framework is further illustrated through three representative systems: (i) magnetic materials, where magnon and paramagnon entropy sustain thermopower across TC and TN; (ii) superconducting Nb, where anomalous thermopower emerges from entropy carried by Bogoliubov quasiparticles near TC; and (iii) a single-molecule junction, where entropy from occupation-number fluctuations governs thermopower in an open quantum system. We validate our unifying principle by comparing it with experimental data: thermopower measurements of superconducting niobium reveal the role of quasiparticle entropy near the critical temperature, and literature-reported specific heat data from a wide range of ferromagnetic and antiferromagnetic materials demonstrate consistent entropy-based scaling across magnetic transitions.
Materials Science (cond-mat.mtrl-sci)
23 pages, 11 figures
Liquid and solid layers in a thermal deep learning machine
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-10 20:00 EDT
Gang Huang, Lai Shun Chan, Hajime Yoshino, Ge Zhang, Yuliang Jin
Based on deep neural networks (DNNs), deep learning has been successfully applied to many problems, but its mechanism is still not well understood – especially the reason why over-parametrized DNNs can generalize. A recent statistical mechanics theory on supervised learning by a prototypical multi-layer perceptron (MLP) on some artificial learning scenarios predicts that adjustable parameters of over-parametrized MLPs become strongly constrained by the training data close to the input/output boundaries, while the parameters in the center remain largely free, giving rise to a solid-liquid-solid structure. Here we establish this picture, through numerical experiments on benchmark real-world data using a thermal deep learning machine that explores the phase space of the synaptic weights and neurons. The supervised training is implemented by a GPU-accelerated molecular dynamics algorithm, which operates at very low temperatures, and the trained machine exhibits good generalization ability in the test. Global and layer-specific dynamics, with complex non-equilibrium aging behavior, are characterized by time-dependent auto-correlation and replica-correlation functions. Our analyses reveal that the design space of the parameters in the liquid and solid layers are respectively structureless and hierarchical. Our main results are summarized by a data storage ratio – network depth phase diagram with liquid and solid phases. The proposed thermal machine, which is a physical model with a well-defined Hamiltonian, that reduces to MLP in the zero-temperature limit, can serve as a starting point for physically interpretable deep learning.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
8 pages, 5 figures
Colloid-like scale-free cluster-cluster aggregation during polymer collapse
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Suman Majumder, Saikat Chakraborty
An extended polymer collapses to form a globule when subjected to a quench below the collapse transition temperature. The process begins with the formation of clusters of monomers or ``pearls’’. The nascent clusters merge, resulting in growth of the average cluster size $ C_s$ , eventually leading to a single globule. The aggregation of the clusters are known to be analogous to droplet coalescence. This suggests a striking resemblance between such an aggregation and cluster-cluster aggregation in colloidal self-assembly, which is characterized by a universal dynamic scaling behavior. Motivated by that, here, we verify the presence of such dynamic scaling during the collapse of a polymer with varying bending stiffness $ \kappa$ , using molecular dynamic simulations. We probe the dynamics via time evolution of the size distribution of clusters $ N_s(t)$ and growth of $ C_s(t)$ . Irrespective of $ \kappa$ , we observe the power-law scalings $ C_s(t)\sim t^z$ and $ N_s(t)\sim t^{-w} s^{-\tau}$ , of which only the cluster growth is universal with $ z\approx 1.65$ . Importantly, our results indeed show that $ N_s(t)$ exhibits a dynamic scaling of the form $ N_s(t)\sim s^{-2}f(s/t^z)$ , indicative of a scale-free cluster growth. Interestingly, for flexible and weakly stiff polymers the dynamic exponents obey the relation $ w=2z$ , as also found in diffusion-controlled cluster-cluster aggregation of particles. For $ \kappa \ge 5$ , the exponents show deviation from this relation, which grows continuously with $ \kappa$ . We identify the differences in local structures of the clusters formed, leading to variations in cluster-size dependence of the effective diffusion constant to be the origin of the above deviation. We also discuss potential experimental strategies to directly visualize the observed dynamic scaling in a collapsing polymer.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
12 pages, 10 figures
Optoelectronically Active GaAs/GeSn-MQW/Ge Heterojunctions Created via Semiconductor Grafting
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Jie Zhou, Haibo Wang, Yifu Guo, Alireza Abrand, Yiran Li, Yang Liu, Jiarui Gong, Po Rei Huang, Jianping Shen, Shengqiang Xu, Daniel Vincent, Samuel Haessly, Yi Lu, Munho Kim, Shui-Qing Yu, Parsian K. Mohseni, Guo-En Chang, Zetian Mi, Kai Sun, Xiao Gong, Mikhail A Kats, Zhenqiang Ma
Traditionally, advancements in semiconductor devices have been driven by lattice-matched heterojunctions with tailored band alignments through heteroepitaxy techniques. However, there is significant interest in expanding the capabilities of heterojunction devices, in particular utilizing extreme lattice mismatches. We demonstrate the manipulation of device behaviors and performance enhancement achievable through a lattice-mismatched, single-crystalline GaAs/GeSn-multi-quantum well (MQW)/Ge n-i-p heterojunction by employing advanced semiconductor grafting technology. With engineered band alignment and optical field distribution, the grafted GaAs/GeSn-MQW/Ge n-i-p photodiode achieved outstanding performance: a record-low dark current density of 1.22E10^-7 A/cm^2, an extended spectral response from ~0.5 to 2 um, and improved photoresponsivity of RVIS of 0.85 A/W and RNIR of 0.40 A/W at 520 and 1570 nm, respectively. The dark current density is at least 5 orders of magnitude lower than state-of-the-art GeSn photodiodes. The photoresponsivity demonstrates an approximately sevenfold enhancement in the VIS range and a threefold improvement in the NIR range compared to the reference epitaxial photodiode. This work presents a unique strategy for constructing lattice-mismatched semiconductor heterojunction devices. More importantly, the implications transcend the current GaAs/GeSn-MQW/Ge example, offering potential applications in other material systems and freeing device design from the stringent lattice-matching constraints of conventional heteroepitaxy.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
25 pages, 6 figures
Strain-Induced Half-Metallicity and Giant Wiedemann-Franz Violation in Monolayer NiI$_2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Strain engineering provides a powerful pathway to manipulate quantum transport in two-dimensional (2D) magnetic semiconductors. Here, we demonstrate that biaxial strain induces a semiconductor-to-half-metal transition in monolayer NiI$ _2$ , triggered by the selective closure of its spin-down band gap while maintaining a robust ferromagnetic ground state. This transition is accompanied by a dramatic and non-monotonic violation of the Wiedemann-Franz law, with the Lorenz number exceeding seven times the Sommerfeld limit ($ L/L_0 \approx 7.17$ ). The anomaly arises from the strain-sensitive hybridization between Ni-$ d$ and I-$ p$ orbitals, leading to a pronounced decoupling between charge and heat transport. These findings establish monolayer NiI$ _2$ as a tunable platform for spin-caloritronic functionalities and a model system for exploring non-Fermi-liquid behavior in low dimensions, thereby opening avenues for energy-efficient quantum devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
10 pages, 7 figures
Crossover between Solid-like and Liquid-like Behavior in Supercooled Liquids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
X. R. Tian, D. M. Zhang, B. Zhang, D. Y. Sun, X. G. Gong
In supercooled liquids, at a temperature between the glass transition temperature Tg and the melting point Tm, thermodynamic properties remain continuous, while dynamic behavior exhibits anomalies. The origin of such thermodynamics-dynamic decoupling has long been a puzzle in the field of glass researches. In this study, we show that the ratio of the alpha-relaxation time associated with the relative and center-of-mass coordinate of nearest-neighbor atomic pairs can effectively characterize the dynamic features of supercooled liquids. With this approach, supercooled liquids can be categorized into two distinct ‘states’ based on their dynamics: solid-like and liquid-like behaviors. We further propose four possible paths from the liquid to the final glass state, each exhibiting unique thermodynamic and dynamic behaviors. Two of these paths predict a characteristic temperature Tx between Tm and Tg, where a crossover between solid-like and liquid-like behaviors occurs in supercooled liquids. The molecular dynamics simulations of several supercooled liquids reveal that the actual path followed by all these systems undergo the crossover between solid-like and liquid-like behaviors. Tx is found to reside in a similar temperature range as the critical temperature Tc in the mode-coupling theory and the breakdown temperature Tb of the Stokes-Einstein relation. This crossover provides a new microscopic perspective for explaining macroscopic dynamic anomalies, and the absence of a typical thermodynamic phase transition at Tg.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn)
Towards a unified understanding of polymer cononsolvency: insights from the Flory-Huggins-Potts framework
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Satyen Dhamankar, Michael A. Webb
In polymer solutions, the phenomenon of cononsolvency describes when mixing two good solvents creates poor-solvent conditions for the polymer over some specific composition range. Observations of cononsolvency typically relate to either phase separation at the macroscopic level or chain collapse at the microscopic level. Despite its technological and biophysical relevance, the connection between the macroscopic and microscopic observations of cononsolvency and how these differ by mechanism remains unclear. In this work, we distinguish between different mechanisms of cononsolvency using various models and observations derived from a single theoretical framework for polymer solutions. We first use mean-field analysis to identify energetic regimes, which are defined by sets of effective $ \chi$ parameters, where changes in solvent/cosolvent composition induce phase separation. Next, to make a connection to the microscopic physics, we conduct Monte Carlo simulations of models with interactions that align with these effective $ \chi$ parameters from these different regimes and observe corresponding composition-induced coil-globule transitions. These transitions are elucidated with signatures associated with specific mechanisms of cononsolvency from the literature. Interestingly, systems with identical effective $ \chi$ parameters can display different mechanisms at the microscopic level. Ultimately, these results provide new insights into cononsolvency that may help to distinguish amongst mechanisms or inform strategies to control polymer solution behavior.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
34 pages, 7 figures, 1 table
Exact eigenvalues and experimental signatures of Heisenberg-Kitaev interactions in spin-1/2 quantum clusters
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Evan M. Wilson, Jian-Xin Zhu, Jason T. Haraldsen
We investigate the thermodynamics and energy eigenstates of a spin-1/2 coupled trimer, tetramer in a star configuration, and tetrahedron. Using a Heisenberg Hamiltonian with additional Kitaev interactions, we explore the thermodynamic signatures of the Kitaev interaction. Our results show that introducing a Kitaev interaction generates a second Schottky anomaly in the heat capacity for systems with a large K/J ratio. The Kitaev term also introduces nonlinear eigenvalues with respect to a magnetic field, pushing the clusters toward a regime similar to the incomplete Paschen-Back effect and triggering first and second-order quantum phase transitions along with robust thermodynamic behavior. Through this approach, we provide exact analytical solutions that offer insights into Kitaev interactions, both in molecular magnets and in extended systems such as honeycomb or Kagome lattices. Furthermore, we provide insight into experimental measurements for detecting Kitaev interactions in clusters.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 7 figures
Bose-Hubbard Model on a Honeycomb Superlattice: Quantum Phase Transitions and Lattice Effects
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-10 20:00 EDT
Wei-Wei Wang, Jin Yang, Jian-Ping Lv, Chao Zhang
We investigate the ground-state and finite-temperature phase diagrams of the Bose-Hubbard model on a honeycomb superlattice. The interplay between the superlattice potential depth $ \Delta/t$ and the onsite interaction $ U/t$ gives rise to three distinct quantum phases at zero temperature: a superfluid phase, a Mott insulator I phase with unit filling on each site, and a Mott insulator II phase characterized by density imbalance-double occupancy on one sublattice and vacancy on the other at unit filling. The SF-MI transitions are found to be continuous, consistent with second-order quantum phase transitions. We further extend our analysis to finite temperatures within the superfluid regime. Our work highlights how a honeycomb superlattice geometry enables access to interaction- and lattice-modulation-driven quantum phases, including a density-imbalanced Mott insulator and a robust superfluid regime, offering concrete theoretical predictions for cold-atom experiments.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
A Heuristic Study of Temperature: Quantum Circuitry in Thermal Systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-10 20:00 EDT
HongZheng Liu, YiNuo Tian, Zhiyue Wu
Classical thermodynamic singularities at phase transitions and in negative-temperature regimes arise because the equal-a-priori probability postulate overlooks the quantum dynamical complexity required to prepare microstates. We promote bounded dynamical complexity to a postulate and develop Complexity Windowed Thermodynamics (CWT). Introducing a finite complexity budget yields the windowed entropy, an entropy of ignorance that is smooth in energy and monotonically non-increasing in the budget. Smoothness guarantees a finite, continuous effective temperature and a non-negative complexity generation potential, thereby regularizing all classical singularities while recovering standard statistical mechanics as the complexity budget approaches infinity. CWT’s generalized first law unveils an information processing work term. From unitary channel geometry we derive universal bounds on action and time: the action consumed must be proportional to the optimal circuit complexity, while the minimum required time is inversely proportional to the effective temperature. The framework unifies phenomena from critical point smoothing to black hole information flow, and predicts that the universe’s total generatable complexity and its holographic entropy are of the same order bridging thermodynamics, quantum computation, and gravity.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Spin pumping driven by magnon-polaritons in a ferromagnet-coplanar superconducting resonator hybrid system
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Dinesh Wagle, Yi Li, Anish Rai, Tomas Polakovic, Valentine Novosad, M. Benjamin Jungfleisch
We demonstrate spin pumping driven by a strongly coupled magnon-photon system using a ferromagnet-coplanar superconducting resonator hybrid system at 1.4 K. Electrical readout via the inverse spin-Hall effect reveals characteristic coupling features, including mode splitting and linewidth broadening, demonstrating the electrical detection of strongly coupled microwave photons and magnons. The magnon-photon coupling strength obtained by combined spin pumping and inverse spin-Hall effect measurements is compared to microwave transmission experiments. Furthermore, microwave power-dependent measurements reveal a decrease in the coupling strength with increasing microwave power alongside the onset of nonlinearities of the superconducting resonator above a critical microwave power threshold.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Spin fluctuations, absence of magnetic order, and crystal electric field studies in the Yb$^{3+}$-based triangular lattice antiferromagnet Rb$_3$Yb(VO$_4$)$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Sebin J. Sebastian, R. Kolay, Abhidev. B, Q.-P. Ding, Y. Furukawa, R. Nath
We report a comprehensive experimental investigation of the structural, thermodynamic, static, and dynamic properties of a triangular lattice antiferromagnet Rb$ 3$ Yb(VO$ 4$ )$ 2$ . Through the analysis of magnetic susceptibility, magnetization, and specific heat, complemented by crystal electric field (CEF) calculations, we confirm the Kramers’ doublet with effective spin $ J{\rm{eff}}=1/2$ ground state. Magnetic susceptibility and isothermal magnetization analysis reveal a weak antiferromagnetic interaction among the $ J{\rm{eff}}=1/2$ spins, characterized by a small Curie-Weiss temperature ($ \theta{\text{CW}}^{\text{LT}}\simeq-0.26$ K) or a reduced exchange coupling ($ J/k_{\rm B} \simeq 0.18$ K). The $ ^{51}$ V NMR spectra and spin-lattice relaxation rate ($ 1/T_1$ ) show no evidence of magnetic long-range-order down to 1.6 K but reflect strong influence of CEF excitations in the intermediate temperatures. At low temperatures, $ 1/T_1(T)$ shows pronounced frequency dependence and $ 1/T_1$ vs field in different temperatures follows the scaling behaviour, highlighting the role of paramagnetic fluctuations. The CEF calculations using the point charge approximation divulge a large energy gap ($ \sim 18.61$ meV) between the lowest and second lowest energy doublets, further establishing Kramers’ doublet as the ground state. Our calculations also reproduce the experimental magnetization and specific heat data and indicate an in-plane magnetic anisotropy. These findings position Rb$ _3$ Yb(VO$ _4$ )$ _2$ as an ideal and disorder-free candidate to explore intrinsic quantum fluctuations and possible quantum spin-liquid physics in a Yb$ ^{3+}$ -based triangular lattice antiferromagnet.
Materials Science (cond-mat.mtrl-sci)
14 pages, 11 figures
Dynamic Fingerprint of Controlled Structural Disorder in Artificial Spin Lattices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Vinayak Shantaram Bhat, M. Benjamin Jungfleisch
Investigating the emergence of complexity in disordered interacting systems, central to fields like spin glass physics, remains challenging due to difficulties in systematic experimental tuning. We introduce a tunable artificial spin lattice platform to directly probe the connection between controlled structural disorder and collective spin-wave dynamics. By precisely varying positional and rotational randomness in Ni81Fe19 nanobar arrays from periodic to random, we map the evolution from discrete spectral modes to a complex, dense manifold. Crucially, we establish a quantitative correlation between information-theoretic measures of static disorder and the dynamic spectral complexity derived from the GHz spin-wave response. This correlation provides a dynamic fingerprint of an increasingly complex energy landscape resulting from tuned disorder. Furthermore, thermal probe via thermal Brillouin light scattering reveal significantly richer microstates diversity in disordered states than driven probe using broadband ferromagnetic resonance. Our work presents a unique experimental testbed for studying how the ingredients of glassy physics manifest in high-frequency dynamics, offering quantitative insights into the onset of complexity in interacting nanomagnet systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Tunability of Robust Exciton-Trion Polaritons in Atomically Thin WS2 Monolayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Xuguang Cao, Debao Zhang, Ji Zhou, Wanggui Ye, Changcheng Zheng, Kenji Watanabe, Takashi Taniguchi, Jiqiang Ning, Shijie Xu
Herein, we present an experimental demonstration of the robust exciton-trion polaritons (ETPs) by measuring and simulating the resonance reflectance spectra of various configurational WS2 monolayers with different dielectric screenings. Moreover, the oscillator strength and decoherent behavior of such hybrid ETPs can be tuned via utilizing dielectric screening effect. The effect is attributed to the regulation of the Coulomb coupling between excitons and trions by changing the surrounding dielectric constant. The demonstration and tunability of the robust ETPs offers a novel pathway for researching novel phases of quantum matter in a quantum many-body physics regime.
Materials Science (cond-mat.mtrl-sci)
Accelerating Two-Dimensional Materials Research via a Universal Interatomic Potential and Large Language Model Agent
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Haidi Wang, Yufan Yao, Haonan Song, Xiaofeng Liu, Zhao Chen, Weiwei Chen, Weiduo Zhu, Zhongjun Li, Jinlong Yang
Accurate interatomic potentials (IAPs) are essential for modeling the potential energy surfaces (PES) that govern atomic interactions in materials. However, most existing IAPs are developed for bulk materials and struggle to accurately and efficiently capture the diverse chemical environment of two-dimensional (2D) materials. This limitation poses a significant barrier to the large-scale design and simulation of emerging 2D systems. To address this challenge, we present a universal interatomic potential tailored for 2D materials. Our model is trained on a dataset comprising 327,062 structure-energy-force-stress mappings derived from 20,114 2D materials, spanning 89 chemical elements. The results show high predictive accuracy, with mean absolute errors of 6 meV/atom for energies, 80 meV/Åfor atomic forces, and 0.067 GPa for stress tensors. It demonstrates broad applicability across a range of atomistic tasks, including structural relaxation, lattice dynamics, molecular dynamics, material discovery, and so on. To further enhance usability and accessibility, we introduce an intelligent agent powered by a large language model (LLM), enabling natural language interaction for 2D materials property simulations. Our work provides not only a precise and universal IAP for 2D systems, but also an intelligent, user-friendly platform that enables high-throughput screening, property prediction, and theoretical exploration, thereby accelerating advances in 2D materials research.
Materials Science (cond-mat.mtrl-sci)
Dimensionless Hierarchical Topological Phononic States
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Joel R. Pyfrom, Kai Sun, Jihong A. Ma
Topological insulators exhibit unique boundary states that are protected by the topology of the bulk bands, a phenomenon that has now been extended to classical systems such as phononics and mechanics. Typically, nontrivial topology in an $ n$ -dimensional bulk leads to the emergence of $ (n-1)$ -dimensional topologically protected boundary states. However, these states can often be gapped out by breaking the symmetry that protects them, resulting in the possible creation of new in-gap higher-order topological modes. A notable example of this is the higher-order topological insulator (HOTI), where gapping out surface states leads to the formation of lower-dimensional topological modes, such as hinge or corner states. This process reduces the spatial dimensionality of the protected modes from $ (n-1)$ to $ (n-2)$ or even lower. In this work, we propose an alternative method to achieve higher-order topological modes using a one-dimensional Su-Schrieffer-Heeger model. Instead of relying on dimensional reduction, we manipulate the positions of domain walls to gap out the originally topologically protected domain-wall states, thereby inducing new higher-order topological states. These new higher-order topological states can be characterized using a generalized winding number calculation. This approach allows for the realization of multiple (and even infinite) topological orders within simple 1D lattices while maintaining the principle of bulk-boundary correspondence. Our study reveals a new mechanism that enriches topological hierarchies beyond conventional classifications. Such a mechanism could also be extended to higher dimensions, potentially creating intricate networks of topological states and advancing our control over wave phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
15 pages, 9 figures
All-optical control of antiferromagnetic domains via an inverse optical magnetoelectric effect
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Shingo Toyoda, Vilmos Kocsis, Yusuke Tokunaga, István Kézsmárki, Yasujiro Taguchi, Taka-hisa Arima, Yoshinori Tokura, Naoki Ogawa
Antiferromagnets are a promising platform for next-generation spintronics due to their ultrafast spin dynamics and robustness to external fields. All-optical control of antiferromagnetic order is essential to fully exploit their potential in energy-efficient and high-speed spintronic and memory applications. However, optical writing of antiferromagnetic domains remains a fundamental challenge, as conventional magneto-optical techniques rely on net magnetization, which is absent in antiferromagnets. In certain multiferroic antiferromagnets, the magnetic toroidal moment provides an additional degree of freedom through its inherent magnetoelectric coupling. This coupling at higher frequencies results in the optical magnetoelectric effect (OME), which manifests as a directional asymmetry in light propagation and enables optical probing of antiferromagnetic states. Here, we demonstrate all-optical writing of antiferromagnetic domains using the inverse optical magnetoelectric effect (IOME) in ferrotoroidic LiNiPO4. The writing process is nonvolatile, non-thermal, and deterministic, driven solely by reversing the light propagation direction. This directional control arises from a strong coupling between the photon linear momentum and the magnetic toroidal moment, enabling the repeatable switching between time-reversed domains with arbitrary light polarization. Our findings establish IOME as a distinct mechanism for manipulating antiferromagnetic order, opening a new paradigm in opto-magnetism driven by photon momentum.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Disorder and the Robustness of Superconductivity on the Flat Band
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
Si Min Chan, Benoît Grémaud, G. George Batrouni
We study the interplay between on-site disorder and fermion pairing on the quasi one-dimensional flat band Creutz lattice. Both disorder and flat bands localize particles, but an attractive interaction results in pair formation and delocalization giving rise to superconductivity. In this work, we examine the attractive Hubbard model on the Creutz lattice to study the competition between these two effects and elucidate the properties of the superconducting phase and the localization quantum phase transition as the disorder strength is increased. Our main result is that flat band superconductivity is robust against disorder: The critical disorder strength, $ W_c$ , required to localize the fermion pairs and destroy superconductivity, is finite at any interaction strength, $ U$ , and is proportional to the superconducting weight, $ D_s$ , of the clean system. Using large scale density matrix renormalization group computations, we show that this transition is of the BKT form. In addition, even at very small interaction strength, the localization is not due to single fermion localization but to pair localization. For completeness, we briefly study this disorder-induced localization with mean field theory and show that $ W_c$ can be accurately determined by using an appropriate scaling function.
Superconductivity (cond-mat.supr-con), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el)
Giant Enhancement of Phonon Electron Coupling in Graphene under Femtosecond Laser Heating at Room Temperature
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
In recent years, phonon electron carrier dragging has emerged as an innovative approach for modulating energy transfer in low dimensional systems. In this Letter, we explore the fundamental mechanisms of electron-phonon coupling and the role of thermal lag behavior in ultrafast heat transport. We present a theoretical investigation of non-equilibrium thermal dynamics in graphene under femtosecond laser excitation, emphasizing the role of phonon branch-resolved electron phonon coupling. This framework provides new insight into ultrafast energy transfer processes at femtosecond timescales and illustrates key deviations from the predictions of the classical two temperature model (TTM), particularly in spatially localized heat transport. Our results show that a 190 fs laser pulse induces a strong non-equilibrium state, followed by momentum redistribution among the excited carriers. This is then followed by effective cooling of the carrier distribution on a 450 fs timescale through phonon emission.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Revised version submitted to Journal of Physics D: Applied Physics (manuscript ID: JPhysD-139850.R1)
FeTaX2: A ferrimagnetic quantum anomalous Hall insulator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Yadong Jiang, Huan Wang, Jing Wang
We theoretically propose that the van der Waals layered ternary transition metal chalcogenide FeTaX$ _2$ (X = S, Se, Te) is a new family of ferrimagnetic quantum anomalous Hall insulators with sizable bulk gap and Chern number C = -2. The magnetic ordering originates predominantly from the Fe atoms, where strong ferromagnetic exchange interactions between them induce magnetic moments on the Ta sites, yielding a collinear ferrimagnetic ground state. The large topological gap arises from the deep sd-type band inversion between spin-down Ta d$ _{z^2}$ and d$ _{xy}$ orbitals near the Fermi level-a mechanism unique to d-orbital systems. Remarkably, the Curie temperature of monolayer FeTaX$ _2$ is predicted to significantly exceed that of monolayer MnBi$ _2$ Te$ _4$ . Furthermore, both the Curie temperature and topological gap scale positively with the spin orbit coupling strength of the $ d$ electrons, suggesting a common physical origin. These findings, if realized experimentally, could open new avenues for the research and application of topological quantum physics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Elastic turbulence in highly entangled polymers and wormlike micelles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Theo A. Lewy, Suzanne M. Fielding, Peter D. Olmsted, Rich R. Kerswell
We show theoretically that an initially homogeneous planar Couette flow of a concentrated polymeric fluid is linearly unstable to the growth of two-dimensional (2D) perturbations, within two widely used constitutive models: the Johnson-Segalman model and the Rolie-Poly model. We perform direct nonlinear simulations of both models in 2D to show that this instability leads to a state of elastic turbulence comprising several narrow shear bands that dynamically coalesce, split and interact. Importantly, we show that this 2D instability arises not only in fluids that have a non-monotonic constitutive curve, and therefore show shear banding in 1D calculations, but also in shear thinning fluids with a monotonic constitutive curve, for which an initially homogeneous base state is stable in 1D. For the former category, the high shear branch of the constitutive curve is unstable to 2D instability in both models, so that the high shear band may be turbulent. In the Rolie-Poly model, the low shear branch is also likewise unstable. Our work provides the first simulation evidence for elastic turbulence in highly entangled polymeric fluids. It also potentially explains rheo-chaotic states seen experimentally in shear banding wormlike micelles. We additionally demonstrate elastic turbulence within both models in the planar Poiseuille geometry.
Soft Condensed Matter (cond-mat.soft)
9 pages, 4 figures
Emergent gapless spiral phases and conformal Lifshitz criticality in the cluster Ising model with off-diagonal interactions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Wei-Lin Li, Dan-Dan Liang, Zhi Li, Xue-Jia Yu
We perform a comprehensive analytical study of the exotic quantum phases and phase transitions emerging from the cluster-Ising model with off-diagonal Gamma interactions. Specifically, we map out the ground-state phase diagram by analyzing both local and nonlocal order parameters, together with the energy spectra. The results reveal two pairs of gapped phases, namely and antiferromagnetic (AFM) long-range ordered phases, symmetry-protected topological (SPT) phases, as well as two distinct gapless spiral phases induced by the off-diagonal interactions, which are related by a duality transformation and are numerically confirmed through the long-distance behavior of various order parameters. Remarkably, four distinct phase transition lines emerge in the phase diagram. Two of them, which separate the distinct gapped or gapless phases, are described by the Ising and three copy Ising conformal field theories, respectively. In contrast, the remaining two transition lines, between the gapless spiral and gapped phases, belong to a nonconformal Lifshitz criticality with dynamical critical exponent $ z = 2$ . More importantly, the intersection of these four transition lines gives rise to a new Lifshitz multicritical point exhibiting emergent conformal symmetry, marking a fundamental departure from all previously known nonconformal Lifshitz points. This work provides a valuable reference for future investigations of exotic gapless phases and their transitions in exactly solvable many-body systems.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
14 pages, 11 figures
Dumbbell dimer dynamics in three-dimensional chiral fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Michalis Chatzittofi, Yuto Hosaka
We study the emergent orientational dynamics of a dumbbell dimer – two asymmetric monomers connected by a linking spring – in a three-dimensional chiral environment with odd viscosity. In classical systems with conserved parity symmetry, reciprocal oscillations of a dimer does not lead to rotational motion. Here, through an analytical calculation, we find that the presence of chirality in the system induces rotational dynamics as function of the expansion/contraction of the dimer. By incorporating thermal fluctuations, we further find that the rotational diffusivity is affected by the coupling between conformational fluctuations and rotational motion. Our results provide insights into problems where the parity symmetry is broken and can be used as a building block to study similar models at the collective level. These problems include multi-component molecular machines in odd-viscous fluids and systems with charged polymers where oddity is present through external magnetic fields.
Soft Condensed Matter (cond-mat.soft)
Thermodynamic Cost of Random-Time Protocols
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-10 20:00 EDT
We establish an information thermodynamics framework for feedback protocols that rely on temporal information. Using this framework, we show that random-time engines that appear to function as perpetuum mobile, such as stochastically stopped processes or heat engines with random-time protocols, actually satisfy the second law of thermodynamics. We illustrate the principles of temporal information thermodynamics on a random-time version of Szilard’s engine, which is a paradigmatic example of a temporal information engine. Our findings quantify the thermodynamic cost of random times in external protocols, such as, in stochastic resetting protocols or in heat engines with random-time protocols.
Statistical Mechanics (cond-mat.stat-mech)
6 pages, 4 figures
Nickel Doping Unlocks Ambient-condition Photostability in Individual Cesium Lead Bromide Perovskite Quantum Dots
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Jehyeok Ryu, Victor Krivenkov, Adam Olejniczak, Mikel Arruabarrena, Jozef Janovec, Aritz Leonardo, Virginia Martínez-Martínez, Andres Ayuela, Alexey Nikitin, Yury Rakovich
Developing efficient single-photon sources is fundamental to advancing photonic quantum technologies. In particular, achieving scalable, cost-effective, stable, high-rate, and high-purity single-photon emission at ambient conditions is paramount for free-space quantum communication. However, fulfilling all the requirements simultaneously under ambient conditions has remained a significant challenge. Here, the scalable, cost-effective ambient condition synthesis of nickel doped (Ni doped) CsPbBr3 perovskite quantum dots (NPQDs) is presented using a modified ligand-assisted reprecipitation (LARP) method. The resulting individual NPQDs demonstrate remarkable photostability, sustaining their performance for over 10 minutes under ambient conditions with environment humidity of 55%, and exhibit exceptional single-photon purity (>99%) with a narrow emission linewidth (70 meV). The remarkable photostability could be attributed to the spatial localization of exciton by Ni atoms on the surface of the nanocrystal, reducing its interaction with the environment. Our results demonstrated that NPQDs with outstanding combinations of quantum emitting properties can be both synthesized and operated at ambient conditions. These findings mark a significant step toward scalable, cost-effective quantum light sources for real-world applications, paving the way for robust quantum communication systems and devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Main text: 19 pages, 4 figures, Submitted to Advanced Materials
Physics of unraveling and micromechanics of hagfish threads
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Mohammad Tanver Hossain, Dakota Piorkowski, Andrew Lowe, Wonsik Eom, Abhishek Shetty, Sameh H. Tawfick, Douglas S. Fudge, Randy H. Ewoldt
Hagfish slime is a unique biological material composed of mucus and protein threads that rapidly deploy into a cohesive network when deployed in seawater. The forces involved in thread deployment and interactions among mucus and threads are key to understanding how hagfish slime rapidly assembles into a cohesive, functional network. Despite extensive interest in its biophysical properties, the mechanical forces governing thread deployment and interaction remain poorly quantified. Here, we present the first direct in situ measurements of the micromechanical forces involved in hagfish slime formation, including mucus mechanical properties, skein peeling force, thread-mucus adhesion, and thread-thread cohesion. Using a custom glass-rod force sensing system, we show that thread deployment initiates when peeling forces exceed a threshold of approximately 6.8 nN. To understand the flow strength required for unraveling, we used a rheo-optic setup to impose controlled shear flow, enabling us to directly observe unraveling dynamics and determine the critical shear rate for unraveling of the skeins, which we then interpreted using an updated peeling-based force balance model. Our results reveal that thread-mucus adhesion dominates over thread-thread adhesion and that deployed threads contribute minimally to bulk shear rheology at constant flow rate. These findings clarify the physics underlying the rapid, flow-triggered assembly of hagfish slime and inform future designs of synthetic deployable fiber-gel systems.
Soft Condensed Matter (cond-mat.soft)
Extreme-Band-Gap Semiconductors with Shallow Dopants and Mobile Carriers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Sieun Chae, Nocona Sanders, Kelsey A. Mengle, Amanda Wang, Xiao Zhang, Jon Lafuente Bartolome, Kaifa Luo, Yen-Chun Huang, Feliciano Giustino, John T. Heron, Emmanouil Kioupakis
The conventional distinction between semiconductors and insulators is often based on the magnitude of the band gap, with materials exhibiting gaps wider than 3 eV typically classified as insulators. However, the emergence of ultra-wide-band-gap (UWBG) semiconductors such as AlGaN, diamond, BN, and Ga2O3 challenges this paradigm for materials classification and raises fundamental questions about the upper bound of band gaps compatible with semiconducting behavior. Here we develop a computational-discovery strategy to identify semiconductors with band gaps exceeding that of AlN (6.2 eV), while retaining essential semiconducting properties such as shallow dopants and mobile charge carriers. We discover that materials composed of light elements in densely packed crystal structures exhibit wide band gaps and light carrier effective masses that enable shallow dopants, high mobility, and weak polaron binding. By applying the hydrogenic Bohr model and first-principles defect calculations - validated against available experimental data - to screen for materials with shallow dopants, we identify dopable compounds with gaps as wide as 9.5 eV that nonetheless host mobile charge carriers. Our findings demonstrate that semiconducting behavior persists even at extreme band gaps, far beyond conventional upper bounds traditionally associated with semiconductor materials.
Materials Science (cond-mat.mtrl-sci)
Gorkov-Hedin Equations for Quantum Many-Body Systems with Spin-Dependent Interactions
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
Driven by the need to understand and determine the presence of non-trivial superconductivity in real candidate materials, we present a generalized set of self-consistent Gorkov-Hedin equations in a vibrating lattice with spin dependent electron-electron and electron-phonon interactions. This extends Hedin’s original equations to treat quantum many-body systems where electronic and lattice correlations along with relativistic effects coexist on the same footing. Upon iterating this set of equations, the corresponding spin-dependent GW approximation and generalized ladder approximations are constructed.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 3 figures
Non-Abelian Magnon Gauge Interactions in Condensed Matter Physics
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
We discuss three different but closely related theories which could describe varieties of condensed matters, in particular the frustrated magnetic materials and the multi-gap (ferro)magnetic superconductors with or without the photon-magnon mixing, where the genuine non-Abelian magnon gauge interaction plays the central role. The charactristic features of these theories are the existence of long range magnetic order and the spin-spin interaction described by the exchange of the messenger bosons, not by the instantaneous action at a distance. These theories could play important roles in our understanding of non-Abelian condensed matters and make the non-Abelian gauge interaction a main stream in the low energy physics. We discuss the physical implications of our results.
Superconductivity (cond-mat.supr-con)
Traveling supersolid stripe patterns in spin-orbit-coupled Bose-Einstein condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-10 20:00 EDT
G. I. Martone, G. V. Shlyapnikov
We consider a traveling supersolid stripe pattern in a spin-orbit-coupled Bose gas. This configuration is associated with an unequal occupation of the two single-particle energy minima, giving rise to a chemical potential difference that sets the fringe velocity. Unlike stationary stripes, the moving pattern is spin-polarized, with decreasing contrast as momentum increases, eventually leading to stripe melting and transition to the uniform plane-wave phase. The Bogoliubov spectrum of the moving stripes exhibits asymmetry under inversion of the excitation quasimomentum. At high momentum, we identify energetic and dynamical instabilities in the spin-phonon mode which transforms to the roton mode of the plane-wave phase as the stripe structure vanishes.
Quantum Gases (cond-mat.quant-gas)
21 pages, 5 figures
High heating rate effects in sintering: A phase-field study of La-doped alumina
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
In recent years high heating rate sintering methods have become a hot topic for reasons of energy efficiency and microstructural optimization. This paper aims to shed light on the microstructural evolution these methods induce by means of phase-field modeling and simulations. A particle-based temperature model suited for the sintering process is developed and coupled with a multiphysics phase-field solver. It is shown that the coupled model exhibits many characteristics typical of high heating rate sintering. Furthermore, the occurrence of temperature and microstructural inhomogeneity as well as their interplay is simulatively explored.
Materials Science (cond-mat.mtrl-sci)
Dual-mode superconducting diode effect enabled by in-plane and out-of-plane magnetic field
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
Chengyu Yan, Huai Guan, Zhenyu Zhang, Yiheng Sun, Qiao Chen, Xinming Zhao, Chuanwen Zhao, James Jun He, Shun Wang
The discovery of the superconducting diode effect (SDE) has been cherished as a milestone in developing superconducting electronics. Tremendous efforts are being dedicated to realizing SDE in a wide variety of material platforms. Despite the diversity in the hosting materials and device designs, SDE is usually operated in a single mode which is enabled by either out-of-plane or in-plane magnetic field/magnetization. In this work, we report the realization of a dual-mode SDE in 2H-$ \mathrm{NbS_2}$ /2H-$ \mathrm{NbSe_2}$ heterostructures where both the out-of-plane magnetic field $ B_{\perp}$ and in-plane magnetic field $ B_{||}$ can independently generate and manipulate SDE. The two modes share similar diode efficiency but differ in two aspects: 1. $ B_{\perp}$ -induced SDE is activated by a field on the order of 1 mT while $ B_{||}$ -induced SDE requires a field on the order of 100 mT; 2. $ \eta$ of $ B_{\perp}$ -induced SDE exhibits a square-root like temperature dependence while $ \eta$ of $ B_{||}$ -induced SDE takes a more linear-like one. We demonstrate that the dual-mode SDE is most likely a result of mirror symmetry breaking along multiple orientations. Thanks to the two orders difference in the operational field for the two modes, we propose a dual-functionality device scheme to showcase the potential of the dual-mode SDE in realizing advanced superconducting architecture, where fast polarity-switching functionality is implemented with $ B_{\perp}$ -induced SDE and high-fidelity functionality is enabled with $ B_{\perp}$ -induced SDE.
Superconductivity (cond-mat.supr-con)
What holes in superconductors reveal about superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
We consider a type I superconducting body that contains one or more holes in its interior that undergoes a transition between normal and superconducting states in the presence of a magnetic field. We argue that unlike other thermodynamic systems that undergo first order phase transitions the system cannot reach its equilibrium thermodynamic state, and that this sheds new light on the physics of the Meissner effect. How the Meissner effect occurs has not been addressed within the conventional theory of superconductivity, BCS. The situation considered in this paper indicates that expulsion of magnetic field requires physical elements absent from Hamiltonians assumed to describe superconductors within BCS theory. These physical elements are essential components of the alternative theory of hole superconductivity.
Superconductivity (cond-mat.supr-con)
Scaling up the transcorrelated density matrix renormalization group
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Benjamin Corbett, Akimasa Miyake
Explicitly correlated methods, such as the transcorrelated method which shifts a Jastrow or Gutzwiller correlator from the wave function to the Hamiltonian, are designed for high-accuracy calculations of electronic structures, but their application to larger systems has been hampered by the computational cost. We develop improved techniques for the transcorrelated density matrix renormalization group (DMRG), in which the ground state of the transcorrelated Hamiltonian is represented as a matrix product state (MPS), and demonstrate large-scale calculations of the ground-state energy of the two-dimensional Fermi-Hubbard model. Our developments stem from three technical inventions: (i) constructing matrix product operators (MPO) of transcorrelated Hamiltonians with low bond dimension and high sparsity, (ii) exploiting the entanglement structure of the ground states to increase the accuracy of the MPS representation, and (iii) optimizing the non-linear parameter of the Gutzwiller correlator to mitigate the non-variational nature of the transcorrelated method. We examine systems of size up to $ 12 \times 12$ lattice sites, four times larger than previous transcorrelated DMRG studies, and demonstrate that transcorrelated DMRG yields significant improvements over standard non-transcorrelated DMRG for equivalent computational effort. Transcorrelated DMRG reduces the error of the ground state energy by $ 3\times$ -$ 17 \times$ , with the smallest improvement seen for a small system at half-filling and the largest improvement in a dilute closed-shell system.
Strongly Correlated Electrons (cond-mat.str-el), Chemical Physics (physics.chem-ph), Quantum Physics (quant-ph)
Zeeman-type spin splittings in strained d-wave altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Yahui Zhai, Longju Yu, Jian Lv, Wei Zhang, Hong Jian Zhao
Recently, altermagnetic materials have become rather attractive because such materials showcase combined advantages of ferromagnets (e.g., spin current) and antiferromagnets (e.g., low stray field and ultrafast spin dynamics). Symmetry arguments imply that d-wave altermagnets may host strain-induced nonrelativistic Zeeman-type spin splittings (ZSSs), but a theoretical, numerical, and experimental justification remains lacking. In the present work, we work with collinear spin point groups (SPGs) and use symmetry analysis to identify 15 SPGs that host strain-induced nonrelativistic ZSSs. These 15 SPGs coincide with the cases associated with d-wave altermagnetic spin splittings reported in literature. We further corroborate our analysis by first-principles numerical simulations, which indicate that a shear strain of 2% creates sizable nonrelativistic ZSSs of up to 177, 100, and 102 meV in CoF2, LiFe2F6 and La2O3Mn2Se2 d-wave altermagnetic semiconductors, respectively. Our work suggests an alternative route toward creating spin current in altermagnets, which may be used to design altermagnetic-based spintronic devices.
Materials Science (cond-mat.mtrl-sci)
8 pages, 4 figures, and 2 tables
Quantum dot transistors based on CVD-grown graphene nano islands
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Takumi Seo, Motoya Shinozaki, Akiko Tada, Yuta Kera, Shunsuke Yashima, Kosuke Noro, Takeshi Kumasaka, Azusa Utsumi, Takashi Matsumoto, Yoshiyuki Kobayashi, Tomohiro Otsuka
Graphene nanoislands (GNIs) are one of the promising building blocks for quantum devices owing to their unique potential. However, direct electrical measurements of GNIs have been challenging due to the requirement of metal catalysts in typical synthesis methods. In this study, we demonstrate electrical transport measurements of GNIs by using microwave plasma chemical vapor deposition, which is a catalyst-free method to deposit graphene directly on SiO$ _2$ substrates. This approach enables the fabrication of metal electrodes on GNIs, allowing us to measure their quantum transport properties. At low temperatures, one of our devices shows clear Coulomb diamonds with twofold degeneracy, indicating the formation of quantum dots and the vanishing of valley degeneracy. The charge state of the GNI is also modulated by a local side gate, and the tunneling coupling between leads and quantum dots is modulated by changing contact area and metal materials. These results provide device design guidelines toward GNI-based quantum devices for next-generation computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 4 figures
Structure-Informed Learning of Flat Band 2D Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Xiangwen Wang, Yihao Wei, Anupam Bhattacharya, Qian Yang, Artem Mishchenko
Flat electronic bands enhance electron-electron interactions and give rise to correlated states such as unconventional superconductivity or fractional topological phases. However, most current efforts towards flat-band materials discovery rely on density functional theory (DFT) calculations and manual band structures inspection, restraining their applicability to vast unexplored material spaces. While data-driven methods offer a scalable alternative, most existing models either depend on band structure inputs or focus on scalar properties like bandgap, which fail to capture flat-band characteristics. Here, we report a structure-informed framework for the discovery of previously unrecognized flat-band two-dimensional (2D) materials, which combines a data-driven flatness score capturing both band dispersion and density-of-states characteristics with multi-modal learning from atomic structure inputs. The framework successfully identified multiple flat-band candidates, with DFT validation of kagome-based systems confirming both band flatness and topological character. Our results show that the flatness score provides a physically meaningful signal for identifying flat bands from atomic geometry. The framework uncovers multiple new candidates with topologically nontrivial flat bands from unlabeled data, with consistent model performance across structurally diverse materials. By eliminating the need for precomputed electronic structures, our method enables large-scale screening of flat-band materials and expands the search space for discovering strongly correlated quantum materials.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Breathing-Driven Metal-Insulator Transition in Correlated Kagome Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Qingzhuo Duan, Zixuan Jia, Zenghui Fan, Runyu Ma, Jingyao Meng, Bing Huang, Tianxing Ma
Inspired by the recent discovery of breathing kagome materials (\rm Nb_3Cl_8) and (\rm Nb_3TeCl_7), we have explored the influence of the breathing effect on the Hubbard model of the kagome lattice. Utilizing the determinant quantum Monte Carlo method, we first investigated the average sign problem in the breathing kagome lattice, which is significantly affected by both the breathing strength and the interaction strength. Secondly, we calculated the electronic kinetic energy, the direct current conductivity, and the electronic density of states at the Fermi level to determine the critical interaction strength for the metal-insulator transition. Our results indicate that the breathing effect, in conjunction with the interaction strength, drives the kagome system from a metal to an insulator. Finally, we evaluated the magnetic properties and constructed a phase diagram incorporating both transport and magnetic properties. The phase diagram reveals that as the interaction strength increases, the system transitions from a paramagnetic metal to a Mott insulator. Our research provides a theoretical guidance for utilizing the breathing effect to control the band gaps, conductivity, and magnetic properties of kagome materials with electronic interactions.
Strongly Correlated Electrons (cond-mat.str-el)
7 Pages and 7 Figures
Si Intercalation Beneath Epitaxial Graphene: Modulating Mott States at the SiC(0001) Interface
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Niclas Tilgner, Zamin Mamiyev, Susanne Wolff, Philip Schädlich, Fabian Göhler, Christoph Tegenkamp, Thomas Seyller
Intercalation has proven to be a powerful tool for tailoring the electronic properties of freestanding graphene layers as well as for stabilizing the intercalated material in a two-dimensional configuration. This work examines Si intercalation of epitaxial graphene on SiC(0001) using three preparation methods. Dangling bond states at the interface were found to undergo a Mott-Hubbard metal-insulator transition as a result of a significant on-site repulsion. Comparing this heterostructure consisting of graphene and a Mott insulator with a similar system without graphene, reveals the screening ability of graphene’s conduction electrons on the on-site repulsion. The system presented here can serve as a template for further research on Mott insulators with variable band gap.
Materials Science (cond-mat.mtrl-sci)
Roles of Non-switchable Domains and Internal Bias in Electrocaloric and Pyroelectric effects
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Jun Usami, Yuki Okamoto, Hisashi Inoue, Takeshi Kobayashi, Hiroyuki Yamada
Solid-state cooling and energy harvesting via pyroelectric effect (PEE) and electrocaloric effect (ECE) in ferroelectric thin films could be enhanced beyond their intrinsic ferroelectric response by exploiting the recently observed direction-dependent enhancement of the PEE; however, its microscopic origin remains unknown. Herein, we report direct hysteresis measurements of pyrocurrent ($ I_{\rm p}$ ) and ECE-induced temperature change versus bias voltage in 1-$ \mu$ m-thick Pb(Zr$ _{0.65}$ Ti$ _{0.35}$ )O$ 3$ capacitors. Both hysteresis loops exhibit pronounced asymmetries along the voltage and response axes. By superimposing direct current voltage offsets, we isolate a residual $ I{\rm p}$ -axis shift, revealing a contribution of non-switchable ferroelectric polarization. This non-switchable polarization can be converted into switchable polarization via poling with bipolar triangular pulses, confirming the governing role of defect-induced domain pinning. After 100 pulses, time-dependent aging was observed for pyroelectric and electrocaloric responses, with the switchable contribution markedly decaying and the non-switchable component remaining nearly constant, indicating partial repinning. The change in voltage-axis shift agrees well with the ratio of non-switchable to switchable polarization, demonstrating that voltage shift also arises from pinned domains. These insights clarify the critical role of non-switchable polarization in the PEE and ECE performance, suggesting strategies to optimize the directional response in ferroelectric devices through controlled poling and defect engineering.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
9 pages, 4 figures
Beyond Scaling: Chemical Intuition as Emergent Ability of Universal Machine Learning Interatomic Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Shinnosuke Hattori, Kohei Shimamura, Aiichiro Nakano, Rajiv K. Kalia, Priya Vashishta, Ken-ichi Nomura
Machine Learning Interatomic Potentials (MLIPs) have successfully demonstrated scaling behavior, i.e. the power-law improvement in training performance, however the emergence of novel capabilities at scale remains unexplored. We have developed Edge-wise Emergent Decomposition (E3D) framework to investigate how an MLIP develops the ability to derive physically meaningful local representations of chemical bonds without explicit supervision. Employing an E(3)-equivariant network (Allegro) trained on molecular data (SPICE~2), we found that the trained MLIP spontaneously learned representations of bond dissociation energy (BDE) by decomposing the global potential energy landscape. The learned BDE values quantitatively agree with literature and its scalability are found to be robust across diverse training datasets, suggesting the presence of underlying representation that captures chemical reactions faithfully beyond given training information. Our E3D analysis utilizing Shannon’s entropy reveals a close interplay between the decomposability of potential energy learning, scalability of learning, and emergent chemical reactivity, thus providing novel insights of scaling limitations and pathways toward more physically interpretable and predictive simulations.
Materials Science (cond-mat.mtrl-sci)
12 pages, 5 figures,
Orbital Hall Effect Enables Field-Free Magnetization Reversal in Ferrimagnets without Additional Conversion Layer
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Zelalem Abebe Bekele, Kun Lei, Xiukai Lan, Xiangyu Liu, Hui Wen, Weihao Li, Yongcheng Deng, Wenkai Zhu, Kaiming Cai, Kaiyou Wang
The spin Hall effect (SHE) enables efficient electrical manipulation of magnetization through the spin Hall current \left(\mathbit{J}{\mathbit{SHE}}\right), advancing energy-efficient spintronics. In parallel, the orbital Hall effect (OHE) offers an alternative pathway to SHE for converting charge current into an angular momentum flow. In this study, we demonstrate field-free current-induced perpendicular ferrimagnetic deterministic switching within a Mo/CoGd device without an additional orbital-to-spin conversion layer. This is achieved by harnessing localized orbital Hall currents \left(\mathbit{J}{\mathbit{OHE}}\right) generated in the Mo layer. The in-plane symmetry breaking at the Mo/CoGd surface-interface layer, validated by a pronounced planar Hall effect, gives rise to a substantial unconventional z-polarized damping-like torque. The CoGd serves a dual role: not only as a converter that transforms the significant \mathbit{J}{\mathbit{OHE}} into \mathbit{J}{\mathbit{SHE}} but also as a ferrimagnetic self-switching mechanism. This dual functionality enables highly efficient field-free current-induced magnetization switching with a critical current density as low as \mathbf{2}.\mathbf{51}\ \times{\mathbf{10}}^\mathbf{6} A cm-2. Our work highlights the potential of orbital Hall currents for energy-efficient magnetization switching, making a notable contribution to the burgeoning field of orbitronics.
Materials Science (cond-mat.mtrl-sci)
Superconducting photocurrents induced by structured electromagnetic radiation
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
O. B. Zuev (Moscow Institute of Physics and Technology, L.D. Landau Institute for Theoretical Physics), M. V. Kovalenko (Moscow Institute of Physics and Technology, L.D. Landau Institute for Theoretical Physics), A. S. Mel’nikov (Moscow Institute of Physics and Technology, Institute for Physics of Microstructures)
We develop a phenomenological theory describing the interaction of superconducting condensate with a Bessel beam of twisted light characterized by a nonzero angular momentum $ m$ . Starting from the time-dependent Ginzburg-Landau model with the complex relaxation time we calculate the spatial profiles of dc photoinduced currents and magnetic fields as well as the second harmonic response. The photocurrents and magnetic fileds are shown to be determined both by the helicity of light and its orbital momentum $ m$ . Analyzing the half-space and thin film geometries we discuss possible experimental tests aimed to probe the superconducting photocurrents and magnetic fields.
Superconductivity (cond-mat.supr-con)
13 pages, 8 figures
Continuous-time multifarious systems – Part I: equilibrium multifarious self-assembly
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Jakob Metson, Saeed Osat, Ramin Golestanian
Multifarious assembly models consider multiple structures assembled from a shared set of components, reflecting the efficient usage of components in biological self-assembly. These models are subject to a high-dimensional parameter space, with only a finite region of parameter space giving reliable self-assembly. Here we use a continuous-time Gillespie simulation method to study multifarious self-assembly and find that the region of parameter space in which reliable self-assembly can be achieved is smaller than what was obtained previously using a discrete-time Monte Carlo simulation method. We explain this discrepancy through a detailed analysis of the stability of assembled structures against chimera formation. We find that our continuous-time simulations of multifarious self-assembly can expose this instability in large systems even at moderate simulation times. While we also observe our predicted instability in discrete-time simulations for small system sizes, discrete-time simulations of large systems show stability in the discrepant region even for long simulation times. For the remaining state space we find good agreement between the predictions of continuous- and discrete-time simulations. We present physical arguments that can help us predict the state boundaries in the parameter space, and gain a deeper understanding of multifarious self-assembly.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Continuous-time multifarious systems – Part II: non-reciprocal multifarious self-organization
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
Jakob Metson, Saeed Osat, Ramin Golestanian
In the context of self-assembly, where complex structures can be assembled from smaller units, it is desirable to devise strategies towards disassembly and reassembly processes that reuse the constituent parts. A non-reciprocal multifarious self-organization strategy has been recently introduced, and shown to have the capacity to exhibit this complex property. In this work, we study the model using continuous-time Gillespie simulations, and compare the results against discrete-time Monte Carlo simulations investigated previously. Furthermore, using the continuous-time simulations we explore important features in our system, namely, the nucleation time and interface growth velocity, which comprise the timescale of shape-shifting. We develop analytical calculations for the associated timescales and compare the results to those measured in simulations, allowing us to pin down the key mechanisms behind the observed timescales at different parameter values.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
Interacting Dirac magnons in honeycomb ferromagnets CrBr$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Saikat Banerjee, Stephan Humeniuk
We study the effects of magnon-magnon interactions in the two-dimensional van der Waals ferromagnet CrBr$ _3$ focusing on its honeycomb lattice structure. Motivated by earlier theoretical predictions of temperature-induced spectral shifts and van Hove singularities in the magnon dispersion\cite{PhysRevX.8.011010}, we go beyond the commonly used thermal magnon approximation by applying second-order perturbation theory in a fully numerical framework. Our analysis uncovers significant deviations from previous analysis: in particular, the predicted singularities are absent, consistent with recent inelastic neutron scattering measurements\cite{PhysRevLett.129.127201}. Moreover, we find that the temperature dependence of the renormalized magnon spectrum exhibits a distinct $ T^3$ behavior for the optical magnon branch, while retaining $ T^2$ behavior for the acoustic or down magnon band. This feature sheds new light on the collective dynamics of Dirac magnons and their interactions. We further compare the honeycomb case with a triangular Bravais lattice, relevant for ferromagnetic monolayer MnBi$ _2$ Te$ _4$ , and show that both systems lack singular features while displaying quite distinct thermal trends.
Materials Science (cond-mat.mtrl-sci)
14 pages + 11 Figures
Ferroelectric switching of quantum anomalous Hall effects in MnBi2Te4 films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Jiaheng Li, Quansheng Wu, Hongming Weng
The integration of ferroelectric and topological materials offers a promising avenue for advancing the development of quantum material devices. In this work, we explore the strong coupling between topological states and ferroelectricity in the heterostructure formed by interfacing MnBi2Te4 (MBT) thin films and monolayer In2Te3. Our first-principles calculations demonstrate that the polarization direction in In2Te3 can strongly alter electronic band structures in the MBT/In2Te3 heterostructure, and even induces a topological phase transition between quantum anomalous Hall (C = 1) and trivial (C = 0) insulating states, originating from the change of band order induced by the switch of out-of-plane polarization. Our work highlights the promising potential of ferroelectric-topological heterostructures in aiding the development of reconfigurable quantum devices, and creating new possibilities for progress in advanced microelectronic and spintronic systems
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Magnetic structure of the kagome metal YbFe6Ge6 in view of Bragg diffraction
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
A material in possession of localized 4f-electron magnetism and delocalized 3d-electron or band magnetism can often present enigmatic physical phenomena, and there has been a longstanding interest in the kagome metal YbFe6Ge6. More recently, because of an investigation of a so-called anomalous Hall effect, or topological Hall effect, underpinned by a thorough study of its magnetic structures using neutron diffraction and single crystals [W. Yao et al., Phys. Rev. Lett. 134, 186501 (2025)]. The authors endorse a magnetic structure of Fe ions in the low temperature phase originally mis-reported in their diffraction patterns. The orthorhombic magnetic space group inferred from the endorsed structure is P(parity)T(time)-symmetric (anti-inversion (-1’) a linear magneto-electric, like an altermagnet. Calculated Bragg diffraction patterns for future x-ray and neutron experiments are rich in Fe magnetic properties of orthorhombic YbFe6Ge6, including space-spin correlations, anapoles and Dirac quadrupoles familiar in high-Tc ceramic superconductors. Iron moments in the two-dimensional layers of a hexagonal nuclear structure undergo collinear antiferromagnetic order below a temperature = 500 K. The moments depart from the c axis in a spontaneous transition at = 63 K to an orthorhombic structure. The magnetism of Yb ions appears to behave independently, which can be confirmed using resonant x-ray diffraction enhanced by an Fe atomic resonance.
Strongly Correlated Electrons (cond-mat.str-el)
Spin-orbit interaction in tubular prismatic nanowires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Anna Sitek, Sigurdur I. Erlingsson, Andrei Manolescu
We theoretically study the spin-orbit interaction in the outer regions of core-shell nanowires that can act as tubular, prismatic conductors. The polygonal cross section of these wires induces non-uniform electron localization along the wire perimeter. In particular, low-energy electrons accumulate in the corner regions, and in the case of narrow shells, conductive channels form along the sharp edges. In contrast, higher-energy electrons are shifted toward the facets. These two groups of states may be separated by large energy gaps, which can exceed the room-temperature energy in the case of triangular geometries. We compare the impact of spin-orbit interaction on the corner and side states of hexagonal and triangular shells grown on hexagonal cores as well as on triangular shells grown on triangular cores. We find that the spin-orbit splitting, and thus the degeneracy of energy states at finite wave vectors, strongly depends on the tube’s geometry. We demonstrate that the weak spin-orbit coupling observed in clean wires can be significantly enhanced if the intermixing of core and shell materials takes place. Moreover, we show that the energy spectrum in the presence of spin-orbit interaction allows for estimating the interaction between states and shows that triangular shells can act as three independent wires in the low-energy regime, while they behave as interacting systems at higher energy ranges.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 13 figures, 60 references
Temperature-Noise Interplay in a Coupled Model of Opinion Dynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-10 20:00 EDT
Anna Chmiel, Julian Sienkiewicz
We consider a coupled system mimicking opinion formation under the influence of a group of $ q$ neighbors ($ q$ -lobby) that consists of an Ising part governed by temperature-like parameter $ T$ and a voter dynamics parameterized by noise probability $ p$ (independence of choice). Using rigorous analytical calculations backed by extensive Monte Carlo simulations, we examine the interplay between these two quantities. Based on the theory of phase transitions, we derive the relation between $ T$ and $ p$ at the critical line dividing the ordered and disordered phases, which takes a very simple and generic form $ T(p-a)=b$ in the high temperature limit. For specific lobby sizes, we show where the temperature are noise are balanced, and we hint that for large $ q$ , the temperature-like dynamics prevails.
Statistical Mechanics (cond-mat.stat-mech), Physics and Society (physics.soc-ph)
Spin Dynamics and Light-Induced Effects in EuZn$_2$P$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
M. Dutra, G. G. Vasques, P. C. Sabino, J. G. Dias, J. F. Oliveira, M. A. A. Heringer, M. Cabrera-Baez, E. Baggio-Saitovitch, A. R. V. Benvenho, M. A. Avila, J. Munevar
The magnetic spin dynamics and optical properties of EuZn$ _2$ P$ 2$ are studied. Single crystals grown by the Sn-flux method crystallize in the $ P\overline{3}m1$ (No.~164) space group and order antiferromagnetically at $ T_N=23.5$ ~K. $ ^{151}$ Eu Mössbauer spectroscopy confirms the presence of the Eu$ ^{2+}$ oxidation state only and the magnetic moment angle relative to the $ c$ -axis is $ \theta=46(3)$ \textdegree. Temperature-dependent electron spin resonance (ESR) measurements reveal that spin-spin interactions predominantly govern the spin relaxation mechanisms, as evidenced by the linewidth behavior ($ \Delta H$ ). Positive $ g$ -shifts ($ \Delta g)$ for $ H \parallel ab$ indicate the presence of local electron polarization. The ESR data support the formation of anisotropic magnetic polarons, which trap spin carriers and contribute to increased electrical resistance. Angular-dependent ESR spectra at room temperature display anisotropic behavior in both $ \Delta g(\phi)$ and $ \Delta H(\phi)$ , with a dominant three-dimensional component $ C{3D}$ , indicative of robust interlayer coupling and antiferromagnetic fluctuations. Under light illumination, a small broadening of $ \Delta H$ is observed. Furthermore, a photovoltaic effect is identified in EuZn$ _2$ P$ _2$ , with photodetector performance metrics suggesting promising capabilities for future optoelectronic devices.
Strongly Correlated Electrons (cond-mat.str-el)
11 pages, 8 figures
Generalized Symmetries Phase Transitions with Local Quantum Fields
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Symmetries are important guiding principle for phase transitions. We systematically construct field theory models with local quantum fields that exhibit the following phase transitions: (1) different symmetry protected topological (SPT) phases with generalized symmetries; (2) different symmetry enriched topological (SET) phases with generalized symmetries differ by symmetry fractionalizations; (3) spontaneously broken generalized symmetries, where the unbroken phases can have nontrivial SPT or SET. The models are ordinary gauge theories with bosons or fermions in 3+1d and 2+1d. We focus on one-form symmetries and symmetries generated by condensation defects, which do not act on local operators. The phase transitions are protected from local operator perturbations which do not change the asymptotic phases. In particular, we show that continuous gauge theories in 3+1d can have different phases distinguished by fractionalizations of unbroken one-form symmetries.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
30 pages, 9 figures
$d$-Wave Flat Fermi Surface in Altermagnets Enables Maximum Charge-to-Spin Conversion
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Junwen Lai, Tianye Yu, Peitao Liu, Long Liu, Guozhong Xing, Xing-Qiu Chen, Yan Sun
Altermagnets combine antiferromagnetic order with ferromagnet-like spin splitting, a duality that unlocks ultrafast spin-dependent responses. This unique property creates unprecedented opportunities for spin-current generation, overcoming the intrinsic limitations of conventional spin-transfer and spin-orbit torque approaches in magnetic memory technologies. Here, we establish a fundamental relationship between Fermi surface geometry and time-reversal-odd ($ \mathcal{T}$ -odd) spin currents in altermagnets through combined model analysis and first-principles calculations. We demonstrate that a $ d$ -wave altermagnet with a flat Fermi surface can achieve a theoretical upper limit of charge-to-spin conversion efficiency (CSE) of 100%. This mechanism is realized in the newly discovered room-temperature altermagnetic metal KV$ _2$ O$ _2$ Se, which exhibits a CSE of $ \sim$ 78% at the charge neutrality point, nearly double that of RuO$ _2$ , setting a new record for $ \mathcal{T}$ -odd CSE. Under electron doping, this efficiency further increases to $ \sim$ 98%, approaching the theoretical limit. Our work advances the fundamental understanding of $ \mathcal{T}$ -odd spin currents via Fermi surface geometry engineering and provides key insights for developing next-generation altermagnet-based memory devices.
Materials Science (cond-mat.mtrl-sci)
Unconventional S-orbital state of Tb and cooperative Ru(4d)-Tb(4f) spin-ordering in strongly correlated 4d-4f system, Ba3TbRu2O9
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
E. Kushwaha, G. Roy, A. M. dos Santos, M. Kumar, S. Ghosh, T. Heitmann, T. Basu
The 6H-perovskite Ba3RRu2O9 (R = rare-earth), composed of Ru2O9 dimers connected through RO6 octahedra, exhibits an intriguing variety of magnetic ground states, ranging from non-magnetic to ferromagnetic and antiferromagnetic, depending on the specific R ion. In this study, we investigate the compound Ba3TbRu2O9 using magnetic susceptibility measurements and time-of-flight neutron diffraction experiments. Our combined bulk and microscopic analyses reveal that the Tb4+ (4f7) electronic configuration results in an s-like state with an orbital moment L=0 and spin-only value of S=7/2, and Ru4+ exhibits a spin-only value of S=1 despite the presence of strong spin-lattice coupling in this compound, representing a sharp contrast to other reported members of this family. A cooperative 4d-4f spin ordering is observed below the Neel temperature (around 9.5 K), indicating strong Ru(4d)=Tb(4f) correlations in the system. The Tb-moments order antiferromagnetically in the bc-plane, whereas the Ru-moments are aligned antiferromagnetically along the b-axis. Furthermore, a collinear antiferromagnetic arrangement of spins is observed within the Ru2O9 dimers throughout the structure, unlike other reported members of this series (e.g., Ho and Nd).
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Generating phase singularities using surface exciton polaritons in an organic natural hyperbolic material
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Philip A. Thomas, William P. Wardley, William L. Barnes
Surface polaritons (SPs) are electromagnetic waves bound to a surface through their interaction with charge carriers in the surface material. Hyperbolic SPs can be supported by optically anisotropic materials where the in-plane and out-of-plane permittivies have opposite signs. Here we report what we believe to be the first experimental study of hyperbolic surface exciton polaritons (HSEPs). We study the intensity and phase response of HSEPs in the J-aggregate TDBC (a type-II natural hyperbolic material). HSEPs can be used to generate phase singularities; the behaviour of these phase singularities is a consequence of the hyperbolic nature of TDBC. The combined intensity and phase response of non-hyperbolic and hyperbolic SPs suggests that they are topologically distinct. We predict analogous effects for hyperbolic surface phonon polaritons in hexagonal boron nitride. Our work suggests that organic materials can provide a new platform for the exploration of hyperbolic surface polaritonics at visible frequencies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
26 pages, 14 figures
Universal Efimov spectra and fermionic doublets in highly mass-imbalanced cold-atom mixtures with van der Waals and dipole interactions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-10 20:00 EDT
We study the Efimov states in highly mass-imbalanced three-body systems composed of two identical heavy atoms and one light atom, focusing on the Er-Er-Li and Dy-Dy-Li cold-atom mixtures with strong dipole-dipole interactions between the heavy atoms. By solving the Born-Oppenheimer equation for varying $ s$ -wave scattering lengths between the heavy and light atoms, we demonstrate for both bosonic and fermionic systems that the Efimov spectra and hence the three-body parameters are universal even with the dipole interaction comparable in strength to the van der Waals interaction. While the bosonic systems exhibit Efimov states only in the $ M_z=0$ channel, the fermionic systems show a characteristic doublet of the Efimov states in the $ M_z=0$ and $ M_z = \pm 1$ channels due to the interplay of finite angular momentum and the anisotropy of the dipole interaction. Both numerical results and analytical formula obtained with the first-order perturbation show that the ratio of the three-body parameters between these two fermionic channels exhibits universality, particularly well in the limit of large mass imbalance. Leveraging this universality, we provide quantitative predictions for the values and ratios of the three-body parameters for experimentally relevant Er-Li and Dy-Li isotopes.
Quantum Gases (cond-mat.quant-gas)
10 pages, 4 figures
Interlayer Pairing in Bilayer Nickelates
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Thomas A. Maier, Peter Doak, Ling-Fang Lin, Yang Zhang, Adriana Moreo, Elbio Dagotto
The discovery of $ T_c\sim 80$ ~K superconductivity in pressurized La$ _3$ Ni$ 2$ O$ 7$ has launched a new platform to study high-temperature superconductivity. Using non-perturbative dynamic cluster approximation quantum Monte Carlo calculations, we characterize the magnetic and superconducting pairing behavior of a realistic bilayer two-orbital Hubbard-Hund model of this system that describes the relevant Ni $ e_g$ states with physically relevant interaction strengths. We find a leading $ s^\pm$ superconducting instability in this model and show that this state primarily arises from interlayer pairing in the $ d{3z^2-r^2}$ orbital that is driven by strong interlayer spin-fluctuations in that orbital. These results provide non-perturbative evidence supporting the picture that a simple single-orbital bilayer Hubbard model for the Ni $ d{3z^2-r^2}$ orbital provides an excellent low-energy effective description of the superconducting behavior of La$ _3$ Ni$ _2$ O$ _7$ .
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Interface Fragmentation via Horizontal Vibration: A Pathway to Scalable Monodisperse Emulsification
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
We present a scalable method for producing monodisperse microscale emulsions in a container holding two stably stratified layers of immiscible liquids by applying horizontal vibration. Our experiments and theoretical modelling show that the critical non-dimensional acceleration for regular droplet formation is governed by a shear-dominated breakup mechanism, which scales as $ N^{-1/2} \omega^{\ast3/2}$ , where $ N$ is the viscosity ratio and $ \omega^{\ast}$ is the frequency of forcing on the viscous-capillary scale. The droplet diameter can be easily controlled by varying the forcing parameters, thus demonstrating this vibrational configuration as a scalable alternative to microfluidics.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
6 pages, 6 figures
Erbium-implanted WS2 flakes with room-temperature photon emission at telecom wavelengths
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Guadalupe García-Arellano, Gabriel I. López Morales, Zav Shotan, Raman Kumar, Ben Murdin, Cyrus E. Dreyer, Carlos A. Meriles
Optically addressable spin impurities in crystals along with device engineering provide an attractive route to realizing quantum technologies in the solid state, but reconciling disparate emitter and host material constraints for a given target application is often challenging. Rare-earth ions in two-dimensional (2D) materials could mitigate this problem given the atomic-like transitions of the emitters and the versatile nature of van der Waals systems. Here we combine ion implantation, confocal microscopy, and ab-initio calculations to examine the photon emission of Er-doped WS2 flakes. Optical spectroscopy reveals narrow, long-lived photo-luminescence lines in the telecom band, which we activate after low-temperature thermal annealing. Spectroscopic and polarization-selective measurements show a uniform response across the ensemble, while the fluorescence brightness remains mostly unchanged with temperature, suggesting non-radiative relaxation channels are inefficient. Our results create opportunities for novel solid state devices coupling 2D-hosted, telecom-band emitters to photonic heterostructures separately optimized for photon manipulation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Nano Lett. 25, 9070 (2025)
Anomalous diffusion and directed coalescence of condensates in driven media
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-10 20:00 EDT
The formation of domains via phase transitions is ubiquitous across physical systems from metallic alloys to biomolecular condensates in cells. We show that when the boundaries between such domains are forced to move, for example by external electrical fields or concentration gradients, this motion internally generates dipole force fields. This translation-induced polarization leads to emergent dipole-dipole interactions that drive directed coalescence of domains, even in the absence of Brownian motion. We then ask how the stochastic motion of individual condensates is driven by active and passive stresses in viscoelastic media such as the cell cytoplasm. Our analysis reveals that active stirring can suppress or enhance the size dependence of diffusion. Together, these findings shed new light on the dynamics of condensates in viscoelastic media and conserved order parameters in general.
Soft Condensed Matter (cond-mat.soft)
Excitonic Properties and Optical Signatures in Quasi-1D Metal-Halide Perovskites with Tunable Octahedral Connectivity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Reducing the dimensionality of metal-halide perovskites enhances quantum and dielectric confinement, enabling tunable excitonic properties. In one dimension, the arrangement of metal-halide octahedra in chains with corner-, edge-, or face-sharing connectivity allows for additional structural flexibility. This not only expands material design possibilities but also reflects quasi-one-dimensional motifs that arise during perovskite formation but are poorly understood. Using first-principles many-body perturbation theory within the $ GW$ and Bethe-Salpeter Equation framework, we provide a comprehensive picture of how one-dimensional confinement, octahedral connectivity and dielectric screening affect optical absorption and exciton photophysics in these materials. Our calculations reveal that increasing octahedral connectivity leads to increased exciton binding and complex, anisotropic optical signatures. However, in experimental compounds, pronounced dielectric screening effects can shift exciton binding energies by several hundred meV, altering these trends. These findings offer insights and design principles for excitonic properties, and aid the interpretation of optical experiments on one-dimensional perovskites.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Vacancy-Controlled Superconductivity in Rock-Salt Carbides: Towards Predictive Modelling of Real-World Superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
Simone Di Cataldo, William Cursio, Lilia Boeri
We critically reexamine the superconducting properties of rock-salt transition-metal carbides (TMCs), often regarded as textbook conventional superconductors, combining first-principles electron-phonon calculations with variable-composition evolutionary structure prediction. Studying superconducting trends across the entire transition-metal series, we find that, when the rock-salt stoichiometric phase is dynamically or thermodynamically unstable, carbon-vacant structures identified through unbiased structure prediction permit to reconcile theoretical calculations with experimental trends. Our integrated use of structure prediction and electron-phonon calculations defines a general framework for realistic modelling of superconductors shaped by non-equilibrium synthesis routes and defect tolerance.
Superconductivity (cond-mat.supr-con)
11 pages, 5 figures, 1 table
Experiment and k$\cdot$p analysis of the luminescence from modulation-doped CdTe/(Cd,Mg)Te quantum wells at magnetic field
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
W. Solarska, M. Grymuza, M. Kubisa, K. Ryczko, P. Pfeffer, K. P. Korona, K. Karpierz, D. Yavorskiy, Z. Adamus, T. Wojtowicz, J. Łusakowski
In spite of a large quantity of papers devoted to the mangetoluminescence from CdTe/(Cd,Mg)Te, quantum wells there have been no attempts to analyze it on the basis of the band-structure calculations. This has been proposed in the present paper. Samples containing one or ten CdTe quantum wells with Cd$ _{0.7}$ Mg$ _{0.3}$ Te barriers are grown by a molecular beam epitaxy on a semi-insulating GaAs substrate. Each well is modulation-doped with iodine donors which leads to the creation of a two-dimensional electron gas in the wells. Polarization-resolved ($ \sigma^+/\sigma^-$ ) photoluminescence spectra are measured at liquid helium temperatures and magnetic fields up to 9 T. The results are interpreted on the basis of calculations of the energy of Landau levels in the conduction and valence bands. In the latter case, we use the Luttinger Hamiltonian while the conduction band is described within a three-level k$ \cdot$ p model. Both models, originally formulated for bulk materials, are adapted for two-dimensional structures. We have found that the majority of all observed transitions is well reproducede by this theory. However, some strong transitions are not which allows us to propose an enlarged scheme of selection rules of the photoluminescence transitions resulting from mixing of the conduction and valence bands. We observe transitions involving Landau levels in the valence band with the index up to 7. To understand the origin of occupation with photoexcited holes of these levels, lying deep in the valence band, we carry out time-resolved measurements which show that the photoexcited barrier is a source of long-lived holes tunneling into the quantum wells. Calculations of the conduction band electron effective g-factor show its strong variation with the electron’s energy and the external magnetic field.
Materials Science (cond-mat.mtrl-sci)
Enhanced Strain Transfer and Optoelectronic Performance in MoS2 Devices via Formvar Encapsulation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Simeon N. Vladimirov, Onur Cakiroglu, Carmen Munuera, Andres Castellanos-Gomez, Thiago L. Vasconcelos
We systematically investigate the influence of polyvinyl formal (PVFM), commonly known as Formvar, in comparison to polycarbonate (PC) and polymethyl methacrylate (PMMA), as encapsulation materials on the strain performance of MoS2 monolayer and bilayer flakes on flexible polypropylene (PP) substrates. Notably, optical differential reflectance measurements reveal that PVFM and PMMA encapsulation significantly enhances the mechanical and thermal strain gauge factors by approximately 2-fold (up to ~-50 meV/%) and 6-fold (up to ~-1.5 meV/°C), respectively, while PC shows a slightly lower enhancement. Moreover, all three polymers increase the maximum achievable strain from approximately 1.4% to 2.3%. Furthermore, devices fabricated on PP substrates exhibit improved optoelectronic performance when encapsulated with PVFM, including increased and faster photocurrent response and extended device lifetime.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
4 figures
2D Mater. 12 025013 (2025)
Linear-response theory in Floquet systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Ayan Pal, Erik G. C. P. van Loon, Ferdi Aryasetiawan
Nonequilibrium quantum physics greatly simplifies in the case of time-periodic Hamiltonians, since Floquet theory provides an analogue to Bloch’s theorem in the time domain. Still, the formal properties of Floquet many-body theory remain underexplored. Here, we develop linear response theory for Floquet systems, in the sense that we have a time-periodic potential of arbitrary strength and a perturbatively small but non-periodic probing field. As an application, we derive the analogy of Fermi’s Golden Rule and the photoemission spectrum of a many-electron system. As in the equilibrium case, the latter is related to the spectral function which is positive definite. We also analyze the parameter dependence of the controllable photoemission spectra by virtue of Floquet engineering.
Strongly Correlated Electrons (cond-mat.str-el)
Modulated Dirac bands and integer hopping ratios in a honeycomb lattice of phenalenyl-tessellation molecules
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Naoki Morishita, Kenshin Komatsu, Motoharu Kitatani, Koichi Kusakabe
A family of nanographene molecules called phenalenyl-tessellation molecules (PTMs) exhibits two types of zero modes: a $ \sqrt{3} \times \sqrt{3}$ type that spreads over the entire molecule and a vacancy-localized type. A periodic system of PTMs is expected to have low-energy bands that strongly reflect the properties of the zero modes of PTMs as effective atoms. In this study, we show that the low-energy Dirac bands in a class of honeycomb PTMs (H-PTM) can be represented by an effective honeycomb model which is determined only by the connections between neighboring effective this http URL hopping parameters of H-PTM in each direction take positive integer ratios according to the connection order between two this http URL structurally designing each PTM, we can change the connection order of the PTMs and hence modulate the energy gap and the Fermi velocity of the Dirac band of the H-PTM. Moreover, we confirm that Dirac bands coexist with vacancy-localized zero modes in the H-PTM with this http URL result indicates that the nanographene structure arranging PTMs as effective atoms extends material design freedom that effectively generates a modulated Dirac electron system with coexisting localized electron spins for graphene-based electronic and quantum devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
27 pages, 11 figures
Physical Review B 111 (2025) 235117
Predicting aqueous and electrochemical stability of 2D materials from extended Pourbaix analyses
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Stefano Americo, Ivano E. Castelli, Kristian S. Thygesen
A key challenge for computational discovery of electrocatalytic materials is the reliable prediction of thermodynamic stability in aqueous environment and under different electrochemical conditions. In this work, we first evaluate the electrochemical stability of more than 3000 two-dimensional (2D) materials using conventional Pourbaix diagrams (CPDs). Due to the complete neglect of thermodynamic barriers along the (often complex) reaction pathways, the vast majority of the materials are predicted to be unstable even though some are known to be stable in practice. We then introduce an analysis based on the surface Pourbaix diagram (SPD) including ‘early intermediate states’ that represent the first steps of the key surface passivation and dissolution reactions. The SPD framework is applied to the 2D materials MoS$ _2$ , phosphorene, and the MXene Ti$ _2$ C, all of which are predicted to be unstable by the CPD. For MoS$ _2$ , our approach reproduces the experimental pH-U stability window as well as the experimental desulphurization potential. For phosphorene and Ti2$ _C$ , the SPD approach is used to investigate the spontaneous degradation mechanism and the potential-dependent surface termination, respectively, again yielding good agreement with experiments. The SPD-based stability analysis emerges as a versatile and quantitative method for prediction of stability and investigation of surface structures in electrochemical environments.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
15 pages, 5 figures, 1 table
ACS Electrochemistry 1.5 (2025): 718-729
Supermodulation-driven evolution of the nodal structure of bismuth-based cuprate superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-10 20:00 EDT
Recent work has shown novel properties of twisted cuprates. In this paper, I point out that related phenomena occur intrinsically in bismuth-based cuprate superconductors due to the presence of the BiO supermodulation. As the ratio of the supermodulation potential to the superconducting energy gap increases, two critical points are found where semi-Dirac nodes form (that is, that have quadratic dispersion in one direction and liner dispersion in the orthogonal direction). The first critical point should be realized in Bi2212, the second in Bi2201. Implications of these findings are discussed.
Superconductivity (cond-mat.supr-con)
Landau theory of the density wave transition in trilayer Ruddlesden-Popper nickelates
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
This paper presents a Landau treatment of the incommensurate density wave transition observed in trilayer Ruddlesden-Popper nickelates and uses this to address the nature of the transition. The data are consistent with a spin driven transition with the distinct intertwining of charge and spin order due to being in or proximate to the first order transition region of the Landau phase diagram. From this approach, one also obtains an understanding of the variation of the transition temperature with rare earth size, pressure, and oxygen isotope substitution.
Strongly Correlated Electrons (cond-mat.str-el)
Recoil of a driven tracer in a correlated medium
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-10 20:00 EDT
Marcin Piotr Pruszczyk, Davide Venturelli, Andrea Gambassi
We study the stochastic dynamics of a Brownian particle after it is suddenly released from a harmonic trap moving with constant velocity through a fluctuating correlated medium, described by a scalar Gaussian field with relaxational dynamics and in contact with a thermal bath. We show that, after the release, the particle exhibits recoil, i.e., it moves in the direction opposite to the drag. As expected, this effect vanishes if the field equilibrates instantaneously. The final value of the average position of the particle is reached algebraically in time in the case of conserved dynamics of the field or for non-conserved dynamics at the critical point. Our predictions are expected to be relevant, at least qualitatively, to driven colloidal particles in liquid media close to critical points.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
Common origin of the photoplastic and electroplastic effect in ZnS
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Alexandra Fonseca Montenegro, Sevim Genlik Polat, Md Mohsinur Rahman Adnan, Maryam Ghazisaeidi, Roberto C. Myers
Dislocation motion – the atomic-scale mechanism of crystal plasticity – governs the strength and ductility of materials. In functional materials, external stimuli beyond mechanical stress can also affect dislocation glide. In the wide band gap semiconductor ZnS, optical illumination suppresses plasticity, whereas electric fields can enhance dislocation motion. Here, we show that the common underlying mechanism for these phenomena is the charged dislocations that respond to the changes in carrier concentration. Our prior theoretical work showed that locally charged dislocations in ZnS trap excess carriers, triggering core reconstructions that modify their mobility, with the positively charged Zn-rich core dislocations showing the most drastic change. Here, we validate this prediction experimentally by showing that either optical excitation or electronic doping selectively inhibits the glide of Zn-rich dislocations in epitaxially grown ZnS. First, imaging individual interface misfit dislocations under different optical excitation conditions shows that Zn-core glide is strongly reduced as optical power is increased, while the S-core dislocations show negligible sensitivity to light, marking the first, single dislocation imaging of the photoplastic effect. Next, we show that a similar behavior is observed with direct electron (n-type) doping of ZnS epitaxial layers grown beyond the critical thickness. As the n-type dopant density is increased, the resulting Zn-core dislocation density is reduced by more than one order of magnitude, while the S-core density remains essentially unchanged, causing a sign reversal of the strain-anisotropy with n-type doping. These results demonstrate a common origin for the opto-electronic sensitivity of dislocations in ZnS and provide a pathway for the engineering of dislocation content in compound semiconductors.
Materials Science (cond-mat.mtrl-sci)
9 pages, 5 figures
Disentangling contributions to longitudinal magnetoconductivity for Kramers-Weyl nodes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
We set out to compute the longitudinal magnetoconductivity for an isolated and isotropic Kramers-Weyl node (KWN), existing in chiral crystals, which forms an exotic cousin of the conventional Weyl nodes resulting from band-inversions. The peculiarities of KWNs are many, the principal one being the presence of two concentric Fermi surfaces at any positive chemical potential ($ \mu$ ) with respect to the nodal point. This is caused by a dominant quadratic-in-momentum dispersion, with the linear-in-momentum Dirac- or Weyl-like terms relegated to a secondary status. In a KWN, the chirally-conjugate node typically serves as a mere doppelgänger, being significantly separated in energy. Hence, when $ \mu$ is set near such a node, the signatures of a lone node are probed in the transport-measurements. The intrinsic topological quantities in the forms of Berry curvature and orbital magnetic moment contribute to the linear response, which we determine by exactly solving the semiclassical Bolzmann equations. Another crucial feature is that the two bands at the same KWN node carry actual spin-quantum numbers, thus providing an additional coupling to an external magnetic field ($ \boldsymbol B$ ), and affecting the conductivity. We take this into account as well, and demonstrate that it causes a linear-in-$ B$ dependence, on top of the usual $ B^2$ -dependence.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
12 pages, 4 figures; follow-up work of arXiv:2505.19636
First-principles characterization of native defects and oxygen impurities in GaAs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
We present an investigation of native point defects and oxygen impurities in gallium arsenide (GaAs) using hybrid density-functional calculations. Defects are characterized by their structural, electronic, and optical properties. Dominant native defects are Ga antisites (Ga$ _{\rm As}$ ), As antisites (As$ {\rm Ga}$ ), and/or Ga vacancies ($ V{\rm Ga}$ ) in which As$ {\rm Ga}$ and $ V{\rm Ga}$ are charge-compensating defects under As-rich conditions. On the basis of the calculated defect transition levels, the isolated As$ _{\rm Ga}$ may be identified with the EL2 center reported in experiments. The defect, however, has a negligible nonradiative electron capture cross section and thus cannot be the “main electron trap” as commonly believed. We find that GaAs can have multiple O-related defect centers when prepared under As-rich conditions. The quasi-substitutional O impurity (O$ _{\rm As}$ ) and its complex with two As$ _{\rm Ga}$ defects (O$ _{\rm As}$ -2As$ _{\rm Ga}$ ) have a metastable and paramagnetic middle (neutral) charge state. These two defects have large nonradiative electron capture cross sections and can be effective recombination centers.
Materials Science (cond-mat.mtrl-sci)
10 pages, 7 figures, 3 tables
Scalable Machine Learning Models for Predicting Quantum Transport in Disordered 2D Hexagonal Materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-10 20:00 EDT
Seyed Mahdi Mastoor, Amirhossein Ahmadkhan Kordbacheh
We introduce scalable machine learning models to accurately predict two key quantum transport properties, the transmission coefficient T(E) and the local density of states (LDOS) in two-dimensional (2D) hexagonal materials with magnetic disorder. Using a tight binding Hamiltonian combined with the Non-Equilibrium Green’s Function (NEGF) formalism, we generate a large dataset of over 400,000 unique configurations across graphene, germanene, silicene, and stanene nanoribbons with varying geometries, impurity concentrations, and energy levels. A central contribution of this work is the development of a geometrydriven, physically interpretable feature space that enables the models to generalize across material types and device sizes. Random Forest regression and classification models are evaluated in terms of accuracy, stability, and extrapolation ability. Regression consistently outperforms classification in capturing continuous transport behavior on in-domain data. However, extrapolation performance degrades significantly, revealing the limitations of tree-based models in unseen regimes. This study highlights both the potential and constraints of scalable ML models for quantum transport prediction and motivates future research into physics-informed or graph-based learning architectures for improved generalization in spintronic and nanoelectronic device design.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Stability of bound states in multi-component DFT in absolute coordinate systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-10 20:00 EDT
Homogeneous electron and nuclear gases are transformed to a localized trial density in absolute coordinates of the multi-component hamiltonian to determine the stability of forming bound states. Regions of stability were found both at the high density and low density regimes, where electron-nuclear correlations could play a critical role in the intermediate density regime. The use of Galilean coordinates is motivated for its use in density functional theory to develop kinetic and potential density functionals, from which suitable coordinate transformations to capture electron-nuclear correlations are applied.
Materials Science (cond-mat.mtrl-sci)
Microscopic Mechanism of Anyon Superconductivity Emerging from Fractional Chern Insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-10 20:00 EDT
Fabian Pichler, Clemens Kuhlenkamp, Michael Knap, Ashvin Vishwanath
Fractional quantum Hall (FQH) states and superconductors typically require contrasting conditions, yet recent experiments have observed them in the same device. A natural explanation is that mobile anyons give rise to superconductivity; however, this mechanism requires binding of minimally charged anyons to establish an unusual energy hierarchy. This scenario has mostly been studied with effective theories, leaving open the question of how anyon superconductivity can arise from repulsive interactions. Here, we show that such an energy hierarchy of anyons arises naturally in fractional Chern insulators (FCIs) at fillings $ \nu = 2/(4p \mp 1)$ when they are driven toward a quantum phase transition into a ``semion crystal’’ – an exotic charge-density-wave (CDW) insulator with semion topological order. Near the transition, Cooper-pair correlations are enhanced, so that a conventional charge-2e superconductor appears with doping. Guided by these insights, we analyze a microscopic realization in a repulsive Hubbard-Hofstadter model. Tensor network simulations at $ \nu = 2/3$ reveal a robust FCI that, with increasing interactions, transitions into the semion crystal. Finding a stable semion crystal in such a minimal model highlights it as a viable state competing with conventional CDW and FQH states. In the vicinity of this transition, we find markedly enhanced Cooper pairing, consistent with our theory that the 2e/3 anyon is cheaper than a pair of isolated e/3 anyons. Doping near the transition should in general lead to doping Cooper pairs and charge-2e superconductivity, with chiral edge modes of alternating central charge $ c = \pm2$ , which can coexist with translation symmetry breaking. Our framework unifies recent approaches to anyon superconductivity, reconciles it with strong repulsion and provides guidance for flat band moiré materials such as recent experiments in twisted MoTe$ _2$ .
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
19 pages main text + 7 pages Appendix and References; 7 + 2 figures