CMP Journal 2025-05-13
Statistics
Nature Materials: 1
Nature Nanotechnology: 1
Nature Reviews Materials: 1
Physical Review Letters: 13
Physical Review X: 3
arXiv: 108
Nature Materials
Unveiling high-mobility hot carriers in a two-dimensional conjugated coordination polymer
Original Paper | Coordination polymers | 2025-05-12 20:00 EDT
Shuai Fu, Xing Huang, Guoquan Gao, Petko St. Petkov, Wenpei Gao, Jianjun Zhang, Lei Gao, Heng Zhang, Min Liu, Mike Hambsch, Wenjie Zhang, Jiaxu Zhang, Keming Li, Ute Kaiser, Stuart S. P. Parkin, Stefan C. B. Mannsfeld, Tong Zhu, Hai I. Wang, Zhiyong Wang, Renhao Dong, Xinliang Feng, Mischa Bonn
Hot carriers, inheriting excess kinetic energy from high-energy photons, drive numerous optoelectronic applications reliant on non-equilibrium transport processes. Although extensively studied in inorganic materials, their potential in organic-based systems remains largely unexplored. Here we demonstrate highly mobile hot carriers in crystalline two-dimensional conjugated coordination polymer Cu3BHT (BHT, benzenehexathiol) films. Leveraging a suite of ultrafast spectroscopic and imaging techniques, we map the microscopic charge transport landscape in Cu3BHT films following non-equilibrium photoexcitation across temporal, spatial and frequency domains, revealing two distinct high-mobility transport regimes. In the non-equilibrium regime, hot carriers achieve an ultrahigh mobility of ~2,000 cm2 V-1 s-1, traversing grain boundaries up to ~300 nm within a picosecond. In the quasi-equilibrium regime, free carriers exhibit Drude-type, band-like transport with a remarkable mobility of ~400 cm2 V-1 s-1 and an intrinsic diffusion length exceeding 1 μm. These findings position two-dimensional conjugated coordination polymers as versatile platforms for advancing organic-based hot carrier applications.
Coordination polymers, Electronic materials, Metal-organic frameworks
Nature Nanotechnology
Paddle-like self-stirring nanoreactors with multi-chambered mesoporous branches for enhanced dual-dynamic cascade reactions
Original Paper | Heterogeneous catalysis | 2025-05-12 20:00 EDT
Yuzhu Ma, Peiting Guo, Bing Ma, Hongjin Zhang, Jinying Li, Linlin Duan, Wei Zhang, Shenghong Guo, Aixia Wang, Xin Pu, Jia Jia, Yan Ai, You-Liang Zhu, Zhongyuan Lu, Xiaomin Li, Jian Liu, Dongyuan Zhao
Developing artificial nanomaterial systems that can convert external stimuli to achieve nanoscale self-sustainable motion (for example, self-rotation), and simultaneously integrate and deploy the spatial localization of multiple active sites to unravel the intraparticle diffusion patterns of molecules, is of great importance for green synthetic chemistry. Here we show a paddle-like self-stirring mesoporous silica nanoreactor system with separated chambers and controllable proximity of active sites. The nanoreactors are designed by encapsulating magnetic Fe3O4 (~20 nm) in the first chamber, and meantime, Au and Pd nanocrystals are spatially isolated in different domains. Such a nanoreactor generates nanoscale rotation under the rotating magnetic fields and exhibits an order of magnitude activity enhancement in the cascade synthesis of 5,6-dimethylphenanthridinium (96.4% selectivity) compared with conventional macro-stirring. Meanwhile, we quantitatively uncovered the rotation-induced enhancement in sequential and reverse transfer of reactive intermediates, consequently revealing the relevance of self-rotation and proximity effects in controlling the catalytic performance.
Heterogeneous catalysis, Structural properties
Nature Reviews Materials
Plasmonic lattice lasers
Review Paper | Lasers, LEDs and light sources | 2025-05-12 20:00 EDT
Francisco Freire-Fernández, Sang-Min Park, Max J. H. Tan, Teri W. Odom
Plasmonic lattice lasers offer a promising alternative to compact sources such as vertical-cavity surface-emitting lasers. These lasers have an open-cavity design consisting of periodic lattices of metallic nanoparticles that facilitate integration with both liquid-state and solid-state gain nanomaterials. Recent advances have enabled real-time control over lasing wavelength, tunable multimodal lasing, and design of complex polarization and intensity profiles. In this Review, we summarize key developments in plasmonic lattice lasers over the past 5 years, with a focus on unconventional lattice cavities and how they can facilitate tailored lasing characteristics. We discuss strategies for realizing multicolour and multidirectional emission, the advantages of different gain materials and the challenges of reducing lasing thresholds. Although substantial progress has been made, open questions regarding fabrication precision, threshold engineering and the realization of electrically driven plasmonic lasers remain. Plasmonic lattice lasers are poised to play a critical part in next-generation technologies for optical communication, sensing and quantum applications.
Lasers, LEDs and light sources, Nanophotonics and plasmonics
Physical Review Letters
Tsirelson’s Inequality for the Precession Protocol is Maximally Violated by Quantum Theory
Research article | Quantum foundations | 2025-05-12 06:00 EDT
Lin Htoo Zaw, Mirjam Weilenmann, and Valerio Scarani
The precession protocol involves measuring ${P}{3}$, the probability that a uniformly precessing observable (like the position of a harmonic oscillator or a coordinate undergoing spatial rotation) is positive at one of three equally spaced times. Tsirelson’s inequality, which states that ${P}{3}\le 2/3$ in classical theory, is violated in quantum theory by certain states. In this Letter, we address some open questions about the inequality: What is the maximum violation of Tsirelson’s inequality possible in quantum theory? Might other theories do better? By considering the precession protocol in a theory-independent manner for systems with finitely many outcomes, we derive a general bound for the maximum possible violation. This theory-independent bound must be satisfied by any theory whose expectation values are linear functions of observables—which includes classical, quantum, and all general probabilistic theories—and depends only on the minimum positive and negative measurement outcomes. Given any such two values, we prove by construction that quantum theory always saturates this bound. Some notable examples include the angular momentum of a spin-$3/2$ particle and a family of observables that outperform the quantum harmonic oscillator in the precession protocol. Finally, we also relate our findings to the recently introduced notion of constrained conditional probabilities.
Phys. Rev. Lett. 134, 190201 (2025)
Quantum foundations, Quantum information theory
Generalized Quantum Repeater Graph States
Research article | Photonics | 2025-05-12 06:00 EDT
Bikun Li, Kenneth Goodenough, Filip Rozpędek, and Liang Jiang
All-photonic quantum repeaters are essential for establishing long-range quantum entanglement. Within repeater nodes, reliably performing entanglement swapping is a key component of scalable quantum communication. To tackle the challenge of probabilistic Bell state measurement in linear optics, which often leads to information loss, various approaches have been proposed to ensure the loss tolerance of distributing a single ebit. We have generalized previous work regarding repeater graph states with elaborate connectivity, enabling the efficient establishment of exploitable ebits at a finite rate with high probability. We demonstrate that our new scheme significantly outperforms the previous work with much flexibility and discuss the generation overhead of such resource states. These findings offer new insights into the scalability and reliability of loss-tolerant quantum networks.
Phys. Rev. Lett. 134, 190801 (2025)
Photonics, Quantum communication, Quantum error correction, Quantum networks, Quantum optics, Quantum repeaters
$\mathcal{I}$-Extremization with Baryonic Charges
Gauge-gravity dualities | 2025-05-12 06:00 EDT
Seyed Morteza Hosseini and Alberto Zaffaroni
We propose an entropy function for ${\mathrm{AdS}}{4}$ BPS black holes in M theory with general magnetic charges, resolving in particular a long-standing puzzle about baryonic charges. The entropy function is constructed from a gravitational block defined solely in terms of topological data of the internal manifold. We show that the entropy of twisted black holes can always be reformulated as an $\mathcal{I}$-extremization problem—even in cases where existing large-$N$ field theory computations fail to provide an answer. Furthermore, we correctly reproduce the entropy for a class of known black holes with purely baryonic magnetic charges. Our results offer both a conjecture for the general gravitational block for ${\mathrm{AdS}}{4}$ black holes in M theory and a prediction for the large-$N$ limit of several partition functions whose saddle points have yet to be found.
Phys. Rev. Lett. 134, 191601 (2025)
Gauge-gravity dualities, Quantum aspects of black holes, Supergravity
Observation of an Axial-Vector State in the Study of the Decay $\psi (3686)\rightarrow \phi \eta {\eta }^{‘ }$
Research article | Hadron production | 2025-05-12 06:00 EDT
M. Ablikim et al. (BESIII Collaboration)
Using $(2712.4\pm{}14.3)\times{}{10}^{6}$ $\psi (3686)$ events collected with the BESIII detector at BEPCII, a partial wave analysis of the decay $\psi (3686)\rightarrow \phi \eta {\eta }^{‘ }$ is performed with the covariant tensor approach. In addition to the established states ${h}{1}(1900$) and $\phi (2170)$, an axial-vector state with a mass near $2.3\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is observed for the first time. Its mass and width are measured to be $2316\pm{}{9}{\mathrm{stat}}\pm{}3{0}{\mathrm{syst}}\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and $89\pm{}1{5}{\mathrm{stat}}\pm{}2{6}{\mathrm{syst}}\text{ }\text{ }\mathrm{MeV}$, respectively. The product branching fractions of $\mathcal{B}[\psi (3686)\rightarrow X(2300){\eta }^{‘ }]\mathcal{B}[X(2300)\rightarrow \phi \eta ]$ and $\mathcal{B}[\psi (3686)\rightarrow X(2300)\eta ]\mathcal{B}[X(2300)\rightarrow \phi {\eta }^{‘ }]$ are determined to be $(4.8\pm{}{1.3}{\mathrm{stat}}\pm{}{0.7}{\mathrm{syst}})\times{}{10}^{- 6}$ and $(2.2\pm{}{0.7}{\mathrm{stat}}\pm{}{0.7}{\mathrm{syst}})\times{}{10}^{- 6}$, respectively. The branching fraction $\mathcal{B}[\psi (3686)\rightarrow \phi \eta {\eta }^{‘ }]$ is measured for the first time to be ($3.14\pm{}0.1{7}{\mathrm{stat}}\pm{}0.2{4}_{\mathrm{syst}})\times{}{10}^{- 5}$. The first uncertainties are statistical and the second are systematic.
Phys. Rev. Lett. 134, 191901 (2025)
Hadron production, Particle production, Exotic mesons, Quarkonia
QED Corrections to the Parity-Violating Asymmetry in High-Energy Electron-Nucleus Collisions
Research article | Equations of state of nuclear matter | 2025-05-12 06:00 EDT
Xavier Roca-Maza and D. H. Jakubassa-Amundsen
The parity-violating asymmetry, including leading-order QED corrections to the Coulomb potential, is calculated nonperturbatively by solving the Dirac equation. At GeV collision energies and forward scattering angles, QED effects enhance the asymmetry by approximately 5% for the recently measured nuclei $^{27}\mathrm{Al}$, $^{48}\mathrm{Ca}$, and $^{208}\mathrm{Pb}$. The corrections result in a shift of the estimated neutron radius, leading to an increase in the inferred neutron skin thicknesses of these nuclei and, thus, to the pressure neutrons feel around nuclear saturation density.
Phys. Rev. Lett. 134, 192501 (2025)
Equations of state of nuclear matter, Nuclear structure & decays, Parity
Spin Response of Neutron Matter in Ab Initio Approach
Research article | Neutrino interactions | 2025-05-12 06:00 EDT
J. E. Sobczyk, W. Jiang, and A. Roggero
We propose a general method embedded in the ab initio nuclear framework to reconstruct linear response functions and calculate sum rules. Within our approach, based on the Gaussian integral transform, we consistently treat the ground state and the excited spectrum. Crucially, the method allows for a robust uncertainty estimation of the spectral reconstruction. We employ it to obtain the spin response in neutron matter. Our calculations are performed using state-of-the-art many-body coupled-cluster method and Hamiltonians derived in the chiral effective field theory, emphasizing the analysis of finite-size effects. Our findings reveal that the spin response exhibits a strong dependence on both nuclear interactions and many-body wave functions, offering a new avenue for exploring nuclear correlations and dynamics in infinite systems. This work serves as a stepping stone toward further studies of neutrino interactions in astrophysical environments from first principles.
Phys. Rev. Lett. 134, 192701 (2025)
Neutrino interactions, Nuclear astrophysics, Nuclear many-body theory, Nuclear matter in neutron stars, Neutrinos
Quantum States Imaging of Magnetic Field Contours Based on Autler-Townes Effect in Ytterbium Atoms
Research article | Atomic & molecular processes in external fields | 2025-05-12 06:00 EDT
Tanaporn Na Narong, Hongquan Li, Joshua Tong, Mario Dueñas, and Leo Hollberg
An intercombination transition in Yb enables a novel approach for rapidly imaging magnetic field variations with excellent spatial and temporal resolution and accuracy. This quantum imaging magnetometer reveals ‘’dark stripes’’ that are contours of constant magnetic field visible by eye or capturable by standard cameras. These dark lines result from a combination of Autler-Townes splitting and the spatial Hanle effect in the $^{1}{\mathrm{S}}{0}\text{- }^{3}{\mathrm{P}}{1}$ transition of Yb when driven by multiple strong coherent laser fields (carrier and AM/FM modulation sidebands of a single-mode 556 nm laser). We show good agreement between experimental data and our theoretical model for the closed, 4-level Zeeman shifted V system and demonstrate scalar and vector magnetic field measurements at video frame rates over spatial dimensions of 5 cm with 0.1 mm resolution. Additionally, the $^{1}{\mathrm{S}}{0}\text{- }^{3}{\mathrm{P}}{1}$ transition allows for $\sim \mathrm{\mu }\mathrm{s}$ response time and a large dynamic range (from microtesla to many tesla).
Phys. Rev. Lett. 134, 193201 (2025)
Atomic & molecular processes in external fields, Magnetometry, Strong electromagnetic field effects, Zeeman effect, Atoms, Electric moment
Nonmonotonic Radiative Heat Transfer in the Transition from Far Field to Near Field
Research article | Heat radiation | 2025-05-12 06:00 EDT
Victor Guillemot, Riccardo Messina, Valentina Krachmalnicoff, Rémi Carminati, Philippe Ben-Abdallah, Wilfrid Poirier, and Yannick De Wilde
We present high precision measurements of the radiative heat transfer of a glass microsphere immersed in a thermal bath in vacuum facing three different planar substrates (${\mathrm{SiO}}_{2}$, SiC, and Au), which exhibit very different optical behaviors in the infrared region. Using a thermoresistive probe on a cantilever, we show the nonmonotonic behavior of the radiative flux between the microsphere and its environment when the microsphere is brought closer to the substrate in the far-field to near-field transition regime. We demonstrate that this unexpected behavior is related to the singularities of dressed emission mechanisms in this three-body system sphere-substrate bath with respect to the separation distance.
Phys. Rev. Lett. 134, 193801 (2025)
Heat radiation, Precision measurements
Spontaneous Capillary-Inertial Dewetting at the Microscopic Scale
Research article | Contact line dynamics | 2025-05-12 06:00 EDT
Yile Wang, Yakang Jin, Youquan Jia, Elmar Bonaccurso, Huali Yu, Xu Deng, Zhigang Li, and Longquan Chen
We resolve the dewetting dynamics of water films on partially wetting surfaces at the microscopic scale and highlight its distinctions from liquid wetting. Fast dewetting occurring at the millisecond scale is dominated by capillary and inertial forces, obeying a power law with a wettability-independent exponent, which is different from the capillary-inertial dynamic wetting. Molecular-level inspections of moving contact lines further reveal that liquid molecules retract from solid surfaces through a rolling motion, whereas dynamic wetting proceeds mainly with the sliding motion. These distinct hydrodynamic behaviors and molecular kinetics explicitly suggest that dynamic dewetting is not simply the reverse of dynamic wetting, which has significant implications for interfacial fluid physics.
Phys. Rev. Lett. 134, 194001 (2025)
Contact line dynamics, Drop interactions, Interfacial flows, Surface & interfacial phenomena, Surface tension effects, Wetting, Drop & bubble phenomena, Thin films, Confocal imaging, Imaging & optical processing, Molecular dynamics
Quartic Scaling of Sound Attenuation with Frequency in Vitreous Silica
Research article | Mesoscopics | 2025-05-12 06:00 EDT
Peng-Jui Wang, Agnès Huynh, Jinn-Kong Sheu, Xavier Lafosse, Aristide Lemaître, Benoit Rufflé, René Vacher, Bernard Perrin, Chi-Kuang Sun, and Marie Foret
Many theories predict a quartic increase of the acoustic damping at sub-THz frequencies in glassy media, related to the excess vibrational modes known as the boson peak anomaly. Here by introducing phase-sensitive acoustic spectroscopy techniques with a THz bandwidth, we investigate the acoustic properties of vitreous silica at 15 and 300 K in the crucial but unexplored sub-THz gap region below the boson peak. Our results indicate a negative dispersion below the THz range and the onset of an athermal quartic frequency scaling acoustic attenuation term, which appears above all other thermal losses.
Phys. Rev. Lett. 134, 196101 (2025)
Mesoscopics, Phonons, Thermodynamics, Transport phenomena, Glasses
Vortical Currents and Reciprocal Relations for Transport Coefficients in the Electron Hydrodynamic Regime
Research article | Berry curvature | 2025-05-12 06:00 EDT
Nisarg Chadha and Subroto Mukerjee
We investigate the hydrodynamic regime in metals with momentum-conserving electron-electron scattering. The conservation of momentum results in well-defined dynamics whose effects we investigate via the relevant continuity equations. We find anomalous contributions to the charge and heat transport currents arising from gradients of the velocity field in a semiclassical treatment with a Berry curvature. These contributions are nonvanishing for systems lacking inversion symmetry, and the corresponding transport coefficients do not obey the standard Onsager reciprocity relations. Instead, we show that the response coefficients relating the currents to the stress tensor obey independent reciprocity relations with the stress tensor and thus exhibit cross-tensor effects of charge and heat transport with the momentum transport. The Berry curvature contribution to the stress magnetization tensor is also derived.
Phys. Rev. Lett. 134, 196301 (2025)
Berry curvature, Topological materials, Hydrodynamics
Fractional Quantum Anomalous Hall Effect in a Singular Flat Band
Research article | Flat bands | 2025-05-12 06:00 EDT
Wenqi Yang, Dawei Zhai, Tixuan Tan, Feng-Ren Fan, Zuzhang Lin, and Wang Yao
In the search of fractional quantum anomalous Hall (FQAH) effect, the conventional wisdom is to start from a flat Chern band isolated from the rest of the Hilbert space by band gaps, so that many-body interaction can be projected to a landscape that mimics a Landau level. Singular flat bands (SFB), which share protected touching points with other dispersive bands, represent another type of flat landscapes differing from Landau levels and Chern bands in topological and geometric properties. Here we report the finding of FQAH phases in a SFB, which emerges in the bipartite limit of the nearest-neighbor tight-binding model of twisted bilayer ${\mathrm{MoTe}}_{2}$. At $1/3$ and $2/3$ filling of the SFB, FQAH effects are demonstrated using density matrix renormalization group calculations with all bands, as well as exact diagonalization calculations with the two touching bands. Gapping the band touching can turn the SFB into a nearly flat Chern band, but counterintuitively this suppresses the FQAH effect, as the gap opening introduces strong inhomogeneity to the quantum geometry. An optical scheme to realize such SFB for cold atoms is provided. Our findings uncover a new arena for the exploration of fractional quantum Hall physics beyond the Landau level and Chern insulator paradigms.
Phys. Rev. Lett. 134, 196501 (2025)
Flat bands, Fractional quantum Hall effect, Optical lattices & traps, Quantum anomalous Hall effect, Chern insulators, Strongly correlated systems, Density matrix renormalization group, Mean field theory, Tight-binding model
Multifractional Brownian Motion with Telegraphic, Stochastically Varying Exponent
Research article | Brownian motion | 2025-05-12 06:00 EDT
Michał Balcerek, Samudrajit Thapa, Krzysztof Burnecki, Holger Kantz, Ralf Metzler, Agnieszka Wyłomańska, and Aleksei Chechkin
The diversity of diffusive systems exhibiting long-range correlations characterized by a stochastically varying Hurst exponent calls for a generic multifractional model. We present a simple, analytically tractable model which fills the gap between mathematical formulations of multifractional Brownian motion and empirical studies. In our model, called telegraphic multifractional Brownian motion, the Hurst exponent is modeled by a smoothed telegraph process which results in a stationary beta distribution of exponents as observed in biological experiments. We also provide a methodology to identify our model in experimental data and present concrete examples from biology, climate, and finance to demonstrate the efficacy of our approach.
Phys. Rev. Lett. 134, 197101 (2025)
Brownian motion, Diffusion, Stochastic processes, Non-Markovian processes, Time series analysis
Physical Review X
Superconductivity in the Parent Infinite-Layer Nickelate ${\mathrm{NdNiO}}_{2}$
Research article | Electrical conductivity | 2025-05-12 06:00 EDT
C. T. Parzyck, Y. Wu, L. Bhatt, M. Kang, Z. Arthur, T. M. Pedersen, R. Sutarto, S. Fan, J. Pelliciari, V. Bisogni, G. Herranz, A. B. Georgescu, D. G. Hawthorn, L. F. Kourkoutis, D. A. Muller, D. G. Schlom, and K. M. Shen
Undoped NdNiO2 exhibits superconductivity up to 11 K, challenging the assumption that doping is essential in layered nickelate superconductors.
Phys. Rev. X 15, 021048 (2025)
Electrical conductivity, Superconductivity, Nickelates, Oxides, Resonant inelastic x-ray scattering, X-ray absorption spectroscopy
Beyond-Hubbard Pairing in a Cuprate Ladder
Research article | Spin fluctuations | 2025-05-12 06:00 EDT
Hari Padma, Jinu Thomas, Sophia F. R. TenHuisen, Wei He, Ziqiang Guan, Jiemin Li, Byungjune Lee, Yu Wang, Seng Huat Lee, Zhiqiang Mao, Hoyoung Jang, Valentina Bisogni, Jonathan Pelliciari, Mark P. M. Dean, Steven Johnston, and Matteo Mitrano
High-resolution resonant inelastic x-ray scattering reveals yet-unobserved magnetic excitations in doped cuprate ladders, indicating strong hole pairing beyond Hubbard model predictions.
Phys. Rev. X 15, 021049 (2025)
Spin fluctuations, Superconductivity, Cuprates, Strongly correlated systems, Resonant inelastic x-ray scattering
Thermodynamics of Active Matter: Tracking Dissipation across Scales
Research article | Nonequilibrium statistical mechanics | 2025-05-12 06:00 EDT
Robin Bebon, Joshua F. Robinson, and Thomas Speck
A new theory links microscopic energy use to large-scale behavior in active matter, revealing how dissipation links to pattern formation and offering tools to infer energy flow in synthetic and living systems.
Phys. Rev. X 15, 021050 (2025)
Nonequilibrium statistical mechanics, Active Brownian particles, Dry active matter, Coarse graining
arXiv
Modeling the time evolution of a camphor rotor perturbed by a stationary camphor source
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Jerzy Gorecki, Yuki Koyano, Hiroyuki Kitahata
A self-propelled motion resulting from the dissipation of camphor molecules on the water surface has been attracting scientific attention for more than 200 years. A generally accepted description of the phenomenon includes equations for the object motion coupled with the hydrodynamics of Marangoni flows and the time evolution of camphor surface concentration. The solution of such equations is a numerically complex problem. In recent publications, an alternative approach based on Hamiltonian including the potential term representing Marangoni interactions has been applied to simulate the time evolution of camphor rotors. Such a model represents a significant numerical simplification if compared to the standard description. Here, we comment on the applicability of Hamiltonian approach by applying it to a single camphor rotor perturbed by a camphor disk fixed on the water surface. We demonstrate that in such a case, the approach leads to the results qualitatively different from the experimental ones. Therefore, we doubt in its applicability to describe the time evolution of interacting camphor rotors. We also show that the approximation of the Marangoni forces by a potential gives more realistic results if used together with the equation of motion that includes the hydrodynamic friction. Still, a better agreement with experiments can be obtained by considering an additional equation for the time evolution of camphor surface concentration.
Soft Condensed Matter (cond-mat.soft), Adaptation and Self-Organizing Systems (nlin.AO)
17 pages, 5 figures
Observing structural disorder induced interacting topological phase in an atom array
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-13 20:00 EDT
Zongpei Yue, Yu-Feng Mao, Xinhui Liang, Zhen-Xing Hua, Peiyun Ge, Yu-Xin Chao, Kai Li, Chen Jia, Meng Khoon Tey, Yong Xu, Li You
Topological phases of matter can appear in noninteracting systems, as in band topology, or interacting systems, such as in spin models, with their defining features typically robust against weak disorder. Intriguingly, disorder itself can also induce topological phases–exemplified by the Anderson topological insulator in noninteracting systems. Experimental studies on disorder induced topology have so far been limited to band topology. Here we report direct observations of structural disorder induced many-body interacting topological phase in an atom array at half-filling, whereby random offsets to tweezer locations forming a lattice implement structural disorder, causing fluctuating long-range dipolar interactions between tweezer confined single atoms. The ground state degeneracy in disordered configurations is detected and compared to a regular lattice. The induced topological phase is also vindicated by the spatially resolved atom-atom correlation functions for different forms of dimer compositions. By probing the quench dynamics of a highly excited state, we observe markedly slower decay of edge spin magnetization in comparison to the bulk spin one, consistent with the presence of topologically protected edge modes in disordered lattices. Our experiments open a new direction for studying the interplay between structural disorder and strongly interacting topological matter in Rydberg atom arrays.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Manipulating the topological spin of Majoranas
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Stijn R. de Wit, Emre Duman, A. Mert Bozkurt, Alexander Brinkman, Inanc Adagideli
The non-Abelian exchange statistics of Majorana zero modes make them interesting for both technological applications and fundamental research. Unlike their non-Abelian counterpart, the Abelian contribution $ e^{i \theta}$ , where $ \theta$ is directly related to the Majorana’s topological spin, is often neglected. However, the Abelian exchange phase and hence the topological spin can differ from system to system. For vortices in topological superconductors, the Abelian exchange phase is interpreted as an Aharonov-Casher phase arising from a vortex encircling an $ e/4$ charge. In this work, we show how this fractional charge and hence the topological spin can be manipulated, introducing an additional knob for braiding operations in topological quantum computing. To probe this effect, we propose a vortex interference experiment that reveals the effect of this fractional charge through measurable shifts in the critical current.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
6 pages, 5 figures
Emergent magnetism and spin liquids in an extended Hubbard description of moiré bilayers
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Zhenhao Song, Urban F. P. Seifert, Leon Balents, Hong-Chen Jiang
Motivated by twisted transition metal dichalcogenides (TMDs), we study an extended Hubbard model with both on-site and off-site repulsive interactions, in which Mott insulating states with concomitant charge order occur at fractional fillings. To resolve the charge ordering as well as the fate of the local moments formed thereby, we perform large-scale density matrix renormalization group calculations on cylindrical geometries for several filling fractions and ranges of interaction strength. Depending on the precise parameter regime, both antiferromagnetically ordered as well as quantum-disordered states are found, with a particularly prominent example being a quantum spin liquid-type ground state on top of charge-ordering with effective Kagomé geometry. We discuss the different mechanisms at play in stabilizing various electronic and magnetic states. The results suggest that moiré TMDs are a promising venue for emergent quantum magnetism of strongly interacting electrons.
Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 13 figures
Simulating the non-unitary Yang-Lee conformal field theory on the fuzzy sphere
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Ruihua Fan, Junkai Dong, Ashvin Vishwanath
The fuzzy sphere method has enjoyed great success in the study of (2+1)-dimensional unitary conformal field theories (CFTs) by regularizing them as quantum Hall transitions on the sphere. Here, we extend this approach to the Yang-Lee CFT-the simplest non-unitary CFT. We use an Ising quantum-Hall ferromagnet Hamiltonian with a transverse field and an imaginary longitudinal field, the latter breaks the Hermiticity of the Hamiltonian and thus the unitarity of the associated quantum field theory. Non-unitary conformal field theories-particularly the Yang-Lee CFT-pose significant challenges to conventional fuzzy sphere approaches. To overcome these obstacles, here we utilize a different method for determining critical points that requires no a priori knowledge of CFT scaling dimensions. Our method instead leverages the state-operator correspondence while utilizing two complementary criteria: the conformality of the energy spectrum and its consistency with conformal perturbation theory. We also discuss a new finite-size scaling on the fuzzy sphere that allows us to extract conformal data more reliably, and compare it with the conventional analysis using the (1+1)-dimensional Yang-Lee problem as an example. Our results show broad agreement with previous Monte-Carlo and conformal bootstrap results. We also uncover one previously unknown primary operator and several operator product expansion coefficients.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th)
10 pages, 6 figures, 2 tables
Operator Spreading, Duality, and the Noisy Long-Range FKPP Equation
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-13 20:00 EDT
Tianci Zhou, Éric Brunet, Xiaolin Qi
Operator spreading provides a new characterization of quantum chaos beyond the semi-classical limit. There are two complementary views of how the characteristic size of an operator, also known as the butterfly light cone, grows under chaotic quantum time evolution: A discrete stochastic population dynamics or a stochastic reaction-diffusion equation in the continuum. When the interaction decays as a power function of distance, the discrete population dynamics model features superlinear butterfly light cones with stretched exponential or power-law scaling. Its continuum counterpart, a noisy long-range Fisher-Kolmogorov-Petrovsky-Piscunov (FKPP) equation, remains less understood. We use a mathematical duality to demonstrate their equivalence through an intermediate model, which replaces the hard local population limit by an equilibrium population. Through an algorithm with no finite size effect, we demonstrate numerically remarkable agreements in their light cone scalings.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
4+17 pages, 6 figures
Fractional Chern Insulators and Competing States in a Twisted MoTe$_2$ Lattice Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Yuchi He, S.H. Simon, S.A. Parameswaran
We construct an interacting lattice model for twisted $ \mathrm{MoTe}_{2}$ bilayers at a twist angle of approximately 3.7\degree. We use the infinite density matrix renormalization group (iDMRG) in a cylinder geometry to identify a variety of competing integer and fractional Chern insulators and charge density wave (CDW) states that emerge upon the spontaneous breaking of time reversal symmetry by valley polarization. We use finite-size analysis to establish the robustness of Chern insulating states even in geometries that admit competing CDWs, and explore the phase transitions between these states driven by increasing sublattice potential or interaction strength. Our work highlights the crucial role played by direct spin exchange in stabilizing the parent valley-polarized Chern ferromagnet band, and by the mixing with higher bands in destabilizing CIs/FCIs in favor of CDW orders.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
5+9pages, 4+7 figures
Soft Electromechanical Elastomers Impervious to Instability
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Daniel Katusele, Carmel Majidi, Kaushik Dayal, Pradeep Sharma
Soft dielectric elastomers that can exhibit extremely large deformations under the action of an electric field enable applications such as soft robotics, biomedical devices, energy harvesting among others. A key impediment in the use of dielectric elastomers is failure through instability mechanisms or dielectric breakdown. In this work, using a group-theory based approach, we provide a closed-form solution to the bifurcation problem of a paradigmatical elastomer actuator and discover an interesting result: at a critical electric field, the elastomer becomes impervious to Treloar-Kearsley instability. This limit is reached prior to the typical dielectric breakdown threshold. Our results thus establish a regime of electrical and mechanical loads where the dielectric elastomer is invulnerable to all common failure modes.
Soft Condensed Matter (cond-mat.soft)
To appear in Journal of Applied Mechanics
Defects in vibrated monolayers of equilateral triangular prisms
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Jorge Vega, Enrique Velasco, Yuri Martinez-Raton
We present experimental results in which a quasimonolayer of grains, shaped as equilateral triangular prisms, is vertically vibrated within circular and square confining cavities. The system exhibits a fluid phase characterized by sixfold orientational order. However, the specific geometries of the cavities frustrate this order, leading to the excitation of topological defects that adhere to topological principles. We analyze the distribution of topological charges of these defects and their evolution as a function of the container geometry. In particular, we find that in the circular cavity, both the number and charge of defects remain constant in the steady-state regime, with only defects of charge $ +1$ being excited. In contrast, within the square cavity, with the same topology as the circular cavity, some defects become pinned to the corners of the cavity, developing charges of $ +1$ or $ +2$ . Additionally, free defects with charges of $ \pm 1$ can be excited. Notably, dynamic events occur, such as the fusion of two defects or the creation of two defects from a single one. These events are governed by the conservation of total charge within the cavity and give rise to various system configurations, with rapid transitions between them. The observed dynamic fluctuations in topological charge are remarkable, influenced by both particle shape and cavity geometry. This system of vertically vibrated (dissipative) granular monolayers presents a unique and simple platform for studying topological phenomena, with potential implications for topological effects in equilibrium-oriented fluids.
Soft Condensed Matter (cond-mat.soft)
16 pages, 12 figures
From continuum excitations to sharp magnons via transverse magnetic field in the spin-1/2 Ising-like triangular lattice antiferromagnet Na2BaCo(PO4)2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Leonie Woodland, Ryutaro Okuma, J. Ross Stewart, Christian Balz, Radu Coldea
We report high-resolution inelastic neutron scattering measurements of the excitation spectrum in large single crystals of the spin-1/2 triangular lattice Ising-like antiferromagnet Na2BaCo(PO4)2 in magnetic fields applied transverse to the Ising axis. In the high-field polarized phase above a critical field $ B_{C}$ we observe sharp magnons, as expected in the case of no exchange disorder. Through simultaneous fits to the dispersions including data in polarizing field along the Ising axis, we obtain an excellent match to an Ising-like XXZ Hamiltonian and rule out previously proposed Kitaev exchanges. In the intermediate-field phase below $ B_{C}$ , we observe three dispersive modes, out of which only the lowest energy one is sharp and the others are broad and overlap with continuum scattering. We propose that the broadening effects are due to magnon decays into two-magnon excitations and confirm that such processes are kinematically allowed. The continuum scattering becomes progressively stronger upon lowering field and, at 0.25 T and zero field, it dominates the complete spectrum with no clear evidence for even broadened magnon modes. We discuss the relevance of the continuous manifold of mean-field degenerate ground states of the refined Hamiltonian for capturing the observed spectrum in zero field, and compare the data with the one- and two-magnon spectrum averaged over this manifold. We also propose a model of the interlayer couplings to explain the observed finite interlayer magnetic propagation vector of the zero-field magnetic order; this requires the breaking of the mirror symmetry in the nominal P-3m1 space group and through refinement of x-ray diffraction data on an untwinned single crystal, we indeed confirm a rotation of the CoO6 octahedra around the c-axis, which lowers the symmetry to P-3.
Strongly Correlated Electrons (cond-mat.str-el)
24 pages, 17 figures
Viscous flow model of ion-induced pattern formation: consistency between theory and experiment
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Tyler P. Evans, Scott A. Norris
It is known that ion-irradiation can lead surfaces to spontaneously develop patterns with characteristic length scales on the order of only a few nanometers. Pattern formation typically occurs only for irradiation angles beyond a critical angle, which varies with projectile, target, and irradiation energy. To date, there is no completely unifying physical theory. However, since predictions of the critical angle can be extracted from linear stability analysis of a given model, the ability to explain critical angle selection is a simple but important test of model validity. In this paper, we survey all existing critical angle, wavelength, and in-plane stress data for noble gas broad beam ion-irradiation of silicon and germanium by argon, krypton and xenon at energies from 250eV to 2keV. While neglecting the effects of erosion and redistribution, which are widely regarded as key contributors to ion-induced pattern formation, we find that a viscous flow model is capable of explaining these three types of experimental data simultaneously using only parameters within a physically-reasonable range, and in a manner consistent with the defect kinetics of the amorphous layer. This bolsters the case for viscous flow and stress-driven instabilities as important components of an eventual, unifying model of nanoscale pattern formation under ion bombardment.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft)
Magnetothermal Properties with Sampled Effective Local Field Estimation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Nicholas Brawand, Nima Leclerc, Emiko Zumbro
We introduce a first-principles method for predicting the magnetothermal properties of solid-state materials, which we call Sampled Effective Local Field Estimation. This approach achieves over two orders of magnitude improvement in sample efficiency compared to current state-of-the-art methods, as demonstrated on representative material systems. We validate our predictions against experimental data for well-characterized magnetic materials, showing excellent agreement. The method is fully automated and requires minimal computational resources, making it well suited for integration into high-throughput materials discovery workflows. Our method offers a scalable and accurate predictive framework that can accelerate the design of next-generation materials for magnetic refrigeration, cryogenic cooling, and magnetic memory technologies.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
Phase field model for viscous inclusions in anisotropic networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Aakanksha Gubbala, Anika M. Jena, Daniel P. Arnold, Sho C. Takatori
The growth of viscous two-dimensional lipid domains in contact with a viscoelastic actin network was recently shown to exhibit unusual lipid domain ripening due to the geometry and anisotropy of the actin network [Arnold & Takatori. Langmuir. 40, 26570-26578 (2024)]. In this work, we interpret previous experimental results on lipid membrane-actin composites with a theoretical model that combines the Cahn-Hilliard and Landau-de Gennes liquid crystal theory. In our model, we incorporate fiber-like characteristics of actin filaments and bundles through a nematic order parameter, and elastic anisotropy through cubic nematic gradients. Numerical simulations qualitatively agree with experimental observations, by reproducing the competition between the thermodynamic forces that coarsen lipid domains versus the elastic forces generated by the surrounding actin network that resist domain coarsening. We observe a significant decrease in the growth of domain sizes in the range of $ R(t) \sim t^{0.05-0.25}$ for different actin network stiffness, in sharp contrast to the $ \sim t^{1/3}$ scaling for diffusive growth of domains in the absence of the actin network. Our findings may serve as a foundation for future developments in modeling elastic ripening in complex systems.
Soft Condensed Matter (cond-mat.soft)
Main text is 9 pages with 4 figures. Additional material includes a supplemental appendix and 2 videos
Nodeless Hybridization as Proof of Trivial Topology in Samarium Hexaboride
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
E. D. L. Rienks, P. Hlawenka, J. Sánchez-Barriga, E. Schierle, M. Jugovac, P. Perna, I. Cojocariu, Kai Chen, K. Siemensmeyer, E. Weschke, A. Varykhalov, N. Y. Shitsevalova, V. B. Filipov, S. Gabáni, K. Flachbart, O. Rader
Calculations unanimously predict samarium hexaboride to be a topological Kondo insulator, the first topological insulator driven by strong electron correlation. As of today it appears also experimentally established as the only representative of this material class. Here, we investigate the three-dimensional band structure of SmB$ _6$ and show that it is incompatible with a topological Kondo insulator which must have hybridization nodes at high-symmetry points. In addition we clarify the remaining questions concerning the nature of the surface states with new data. We address consequences for the search for correlated topological insulators.
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 4 figures
Multiple Scattering of Elastic Waves in Polycrystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Anubhav Roy, Christopher M. Kube
Elastic waves that propagate in polycrystalline materials attenuate due to scattering of energy out of the primary propagation direction in addition to becoming dispersive in their group and phase velocities. Attenuation and dispersion are modeled through multiple scattering theory to describe the mean displacement field or the mean elastodynamic Green’s function. The Green’s function is governed by the Dyson equation and was solved previously (Weaver, 1990) by truncating the multiple scattering series at first-order, which is known as the first-order smoothing approximation (FOSA). FOSA allows for multiple scattering but places a restriction on the scattering events such that a scatterer can only be visited once during a particular multiple scattering process. In other words, recurrent scattering between two scatterers is not permitted. In this article, the Dyson equation is solved using the second-order smoothing approximation (SOSA). The SOSA permits scatterers to be visited twice during the multiple scattering process and, thus, provides a more complete picture of the multiple scattering effects on elastic waves. The derivation is valid at all frequencies spanning the Rayleigh, stochastic, and geometric scattering regimes without additional approximations that limit applicability in strongly scattering cases (like the Born approximation). The importance of SOSA is exemplified through analyzing specific weak and strongly scattering polycrystals. Multiple scattering effects contained in SOSA are shown to be important at the beginning of the stochastic scattering regime and are particularly important for transverse (shear) waves. This step forward opens the door for a deeper fundamental understanding of multiple scattering phenomena in polycrystalline materials.
Materials Science (cond-mat.mtrl-sci), Mathematical Physics (math-ph)
Machine Learning Tool to Analyse Spectroscopic Changes in High-Dimensional Data
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-13 20:00 EDT
Alberto Martinez-Serra, Gionni Marchetti, Francesco D’Amico, Ivana Fenoglio, Barbara Rossi, Marco P. Monopoli, Giancarlo Franzese
Fibrinogen is an abundant protein found in human blood plasma that plays crucial roles in various physiological processes. When nanoparticles (NPs) are introduced into a biological solution, layers of biomolecules form on their surface, creating a corona. Understanding how the structure of the protein evolves into the corona is essential for evaluating the safety and toxicity of nanotechnology. However, the influence of NP properties on protein conformation is not well understood. In this study, we propose a new method that addresses this issue by analyzing multi-component spectral data using Machine Learning (ML). We apply the method to fibrinogen at blood concentrations while interacting with hydrophobic carbon or hydrophilic silicon dioxide NPs, revealing striking differences in the temperature dependence of the protein structure between the two cases. Our unsupervised ML method a) does not suffer from the challenges associated with the curse of dimensionality, and b) simultaneously handles spectral data from various sources. The method provides a deeper understanding of the correlation between protein structure and NP interactions, which could support the development of nanomedical tools to treat various conditions.
Statistical Mechanics (cond-mat.stat-mech), Quantitative Methods (q-bio.QM)
30 pages, 9 figures
Microscopic lattice model for quartic semi-Dirac fermions in two dimensions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Mohamed M. Elsayed, Valeri N. Kotov
We propose a lattice model for the realization of exotic quartic semi-Dirac fermions, i.e. quasiparticles exhibiting a dispersion with quartic momentum dependence in a given direction, and a linear dependence in the perpendicular direction. A tight binding model is employed, allowing for hopping between up to fourth nearest neighbors and anisotropic hopping parameters. In addition, we introduce the effects of electron-electron interactions (both long-range Coulomb, and short range) which are necessary to stabilize the quartic semi-Dirac phase; without interactions the lattice is unstable towards formation of anisotropic Dirac cones.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 6 figures
Band topology and dynamic multiferroicity induced from dynamical Dzyaloshinskii-Moriya interactions in centrosymmetric lattices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
We develop a theory of a dynamical Dzyaloshinskii-Moriya interaction (dDMI) in centrosymmetric crystals by generally considering the vibration of both cations and anions. It gives rise to an antisymmetric spin-lattice coupling, inducing magnon-phonon hybridized topological excitations. Moreover, we find that this dDMI naturally exhibits a magnetoelectric feature, leading to the presence of dynamic multiferroicity with finite toroidal moment distribution in the momentum space. By comparing the toroidal moments with the band skyrmion structure, we reveal the intrinsic connection between band topology and dynamic multiferroicity through the dDMI.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Transient size segregation of binary granular mixtures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Soniya Kumawat, Anurag Tripathi
Transient size segregation of a bi-disperse granular mixture flowing over a periodic chute is studied using DEM simulations and theory. A recently developed particle force-based size segregation model has been shown to successfully predict the steady state behavior of binary granular mixtures [1]. This promising model is used to predict the time-dependent segregation of different size binary mixtures in this work. A one dimensional continuum model is developed to solve the convection-diffusion equation by incorporating a mixture segregation model along with rheological model. The inter-coupling of segregation with rheology is accounted to predict evolution of species concentration. We also investigate the effect of different initial configurations (Large near base (LNB), Small near base (SNB) and well-mixed) on the transient evolution of the flow and segregation. The particle force-based segregation model is able to predict the evolution of the concentration profile for all three initial configurations for smallest size ratio of 1.25. Significant deviations, however, are observable for larger size ratios, suggesting the need to account for the evolution of the velocity field in the model.
Soft Condensed Matter (cond-mat.soft)
General First-Principles Approach to Crystals in Finite Magnetic Fields
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Chengye Lü, Yingwei Chen, Yuzhi Wang, Zhihao Dai, Zhong Fang, Xin-Gao Gong, Quansheng Wu, Hongjun Xiang
We introduce a general first-principles methodology for computing electronic structure in a finite uniform magnetic field which allows for an arbitrary rational magnetic flux and nonlocal pseudopotentials, at a comparable time complexity of conventional plane-wave pseudopotential approaches in zero-field conditions. The versatility of this method is demonstrated through comprehensive applications to both molecular and crystalline systems, including calculations of magnetizabilities, magnetically induced currents, and magnetic energy bands. Furthermore, we provide rigorous proofs of two fundamental properties for crystals in uniform magnetic fields: the “strong translational symmetry” and “magnetic bands shift” phenomena.
Materials Science (cond-mat.mtrl-sci)
17 pages, 3 figures
Protected Symmetrical Superconducting Qubit Based on Quantum Flux Parametron
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-13 20:00 EDT
Kian Rafati Sajedi, Mojtaba Hosseinpour Choubi, Mehdi Fardmanesh
Conventional Quantum Flux Parametrons (QFPs) have historically been used for storing classical bits in Josephson junction-based computers. In this work, we propose a novel QFP-based topology dubbed “Degenerium” qubit, to process and compute quantum information. Degenerium combines principles from the 0-$ \pi$ qubit and flux qubit to create ideally degenerate quantum ground states, while significantly simplifying the 0-$ \pi$ qubit structure. The symmetrical design of Degenerium enables easier qubit control and fabrication. We demonstrate that due to the inherent symmetry of Degenerium, our designed qubit is insensitive to fabrication-induced variations in critical current ($ I_c$ ) of the Josephson junctions. Our calculations of depolarization and dephasing rates due to charge, flux, and critical current noise sources result in depolarization and dephasing times of 1.25 s and 90 $ \mu$ s, respectively. Further parameter tuning and optimization is possible to meet specific application demands.
Superconductivity (cond-mat.supr-con)
Optically induced spin Hall current in Janus transition-metal dichalcogenides
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Tomoaki Kameda, Katsunori Wakabayashi
Monolayer Janus transition-metal dichalcogenides (TMDCs), such as WSeTe, exhibit Rashba-type spin-orbit coupling (SOC) due to broken out-of-plane mirror symmetry. Here, we theoretically demonstrate that pure spin Hall currents can be generated under light irradiation based on a tight-binding model. Rashba-type SOC plays a crucial role in determining the spin polarization direction and enhancing the generation efficiency of pure spin Hall currents. Our findings establish Janus TMDCs as promising materials for next-generation optospintronic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 8 figures
Interface-Bound States and Majorana Zero Modes in Lateral Heterostructures of Bi$_2$Se$_3$ and Sb$_2$Te$_3$ with Proximity-Induced Superconductivity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
We present a comprehensive investigation into the emergence of interface-bound states, particularly Majorana zero modes (MZMs), in a lateral heterostructure composed of two three-dimensional topological insulators (TIs), Bi$ _2$ Se$ _3$ and Sb$ _2$ Te$ _3$ , under the influence of proximity-induced superconductivity from niobium (Nb) contacts. We develop an advanced two-dimensional Dirac model for the topological surface states (TSS), incorporating spatially varying chemical potentials and s-wave superconducting pairing. Using the Bogoliubov-de Gennes (BdG) formalism, we derive analytical solutions for the bound states and compute the local density of states (LDOS) at the interface, revealing zero-energy modes characteristic of MZMs. The topological nature of these states is rigorously analyzed through winding numbers and Pfaffian invariants, and their robustness is explored under various physical perturbations, including gating effects. Our findings highlight the potential of this heterostructure as a platform for topological quantum computing, with detailed predictions for experimental signatures via tunneling spectroscopy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
30 pages, 3 figures
Doping Topological Dirac Semimetal with magnetic impurities: electronic structure of Mn-doped Cd$_3$As$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
H. Ness, I. Leahy, A. Rice, D. Pashov, K. Alberi, M. van Schilfgaarde
The prospect of transforming a Dirac topological semimetal (TSM) into a Weyl TSM phase, following doping by magnetic impurities, is central to TSM applications. The magnetic field from polarized $ d$ levels of magnetic impurities produces a field with a sharp local structure. To what extent magnetic impurities act in the same manner as an applied field and what are the effects of such a field on the electronic structure of a Dirac TSM is the subject of this paper. We present electronic structure calculations of bulk Cd$ _3$ As$ _2$ with substitutional doping of Mn impurities in the dilute alloy range. Quasi-particle $ GW$ (QS$ GW$ ) ab-initio electronic structure calculations are used in conjunction with $ k \cdot p$ model Hamiltonian calculations. As expected, we observe the splitting of the Dirac points into pairs of Weyl points following the doping with Mn. We also show that the electronic structure of Mn-doped Cd$ _3$ As$ _2$ can be emulated by the electronic structure of pristine Cd$ _3$ As$ _2$ with an appropriate external magnetic field. Some properties of the conductivity of bulk Cd$ _3$ As$ _2$ for different magnetic field orientations are also investigated. Our results inform future opportunities for unique device functionality based on band structure tuning not found in conventional magnetic Weyl TSM.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Critical States of Fermions with ${\mathbb{Z}}_2$ Flux Disorder
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-13 20:00 EDT
Hiranmay Das, Naba P. Nayak, Soumya Bera, Vijay B. Shenoy
Motivated by many contemporary problems in condensed matter physics where matter particles experience random gauge fields, we investigate the physics of fermions on a square lattice with $ \pi$ -flux (that realizes Dirac fermions at low energies), subjected to flux disorder arising from a random $ {\mathbb{Z}}_2$ gauge field that results from the presence of flux defects (plaquettes with zero flux). At half-filling, where the system possesses BDI symmetry, we show that a new class of critical phases is realized, with the states at zero energy showing a multifractal character. The multifractal properties depend on the concentration $ \mathfrak{c}$ of the $ \pi$ -flux defects and spatial correlations between the flux defects. These states are characterized by the singularity spectrum, Lyapunov exponents, and transport properties. For any concentration of flux defects, we find that the multi-fractal spectrum shows termination, but $ \textit{not freezing}$ . We characterize this class of critical states by uncovering a relation between the conductivity and the Lyapunov exponent, which is satisfied by the states irrespective of the concentration or the local correlations between the flux defects. We demonstrate that renormalization group methods, based on perturbing the Dirac point, fail to capture this new class of critical states. This work not only offers new challenges to theory, but is also likely to be useful in understanding a variety of problems where fermions interact with discrete gauge fields.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
16 pages, 18 figures
Fluxon cotunneling in coupled Josephson junctions: Perturbation theory
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-13 20:00 EDT
Andrew G. Semenov, Alex Latyshev, Andrei D. Zaikin
We investigate the effects of fluxon cotunneling and quantum Coulomb drag in a system of two small Josephson junctions coupled by means of mutual capacitance $ C_m$ . Depending on the value of $ C_m$ we identify three different regimes of strong, intermediate and weak coupling. Focusing our attention on the last two regimes we develop a perturbation theory in the interaction and explicitly derive fluxon cotunneling amplitudes at sufficiently small mutual capacitance values. We demonstrate that the Coulomb drag effect survives at any non-zero $ C_m$ and evaluate the non-local voltage response that is in general determined by a trade off between two different cotunneling processes. Our predictions can be straightforwardly generalized to bilinear Josephson chains and directly verified in future experiments.
Superconductivity (cond-mat.supr-con)
7 pages, 4 figures
Topological properties of a chain of interacting electrons
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Igor N.Karnaukhov, E. E. Krasovskii
Within the framework of a one-dimensional model of interacting electrons, the ground state of an electron liquid is studied. Using the exact solution of the model, the ground state phase diagram and zero-energy Majorana edge functions in a finite chain are calculated. The winding number invariant reflects the topological nature of the electron liquid. The phase diagram includes two topological phases with different winding number invariants, the topologically trivial Mott insulator phase, and three critical phase transition points. Numerical calculations confirm and illustrate the analytical results.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 5 figures
Supersonic Flow Past an Obstacle in a Quasi-Two-Dimensional Lee-Huang-Yang Quantum Fluid
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-13 20:00 EDT
G. H. dos Santos, L. F. Calazans de Brito, A. Gammal, A. M. Kamchatnov
A supersonic flow past an obstacle can generate a rich variety of wave excitations. This paper investigates, both analytically and numerically, two types of excitations generated by the flow of a Lee-Huang-Yang quantum fluid past an obstacle: linear radiation and oblique dark solitons. We show that wave crests of linear radiation can be accurately described by the proper modification of the Kelvin original theory, while the oblique dark soliton solution is obtained analytically by transformation of the 1D soliton solution to the obstacle’s reference frame. A comparison between analytical predictions and numerical simulations demonstrates good agreement, validating our theoretical approach.
Quantum Gases (cond-mat.quant-gas), Pattern Formation and Solitons (nlin.PS)
8 pages, 5 figures
Self-organization of active rod suspensions on fluid membranes and thin viscous films
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Arijit Mahapatra, Ronit Freeman, Ehssan Nazockdast
Many biological processes involve transport and organization of inclusions in thin fluid interfaces. A key aspect of these assemblies is the active dissipative stresses applied from the inclusions to the fluid interface, resulting in long-range active interfacial flows. We study the effect of these active flows on the self-organization of rod-like inclusions in the interface. Specifically, we consider a dilute suspension of Brownian rods of length $ L$ , embedded in a thin fluid interface of 2D viscosity $ \eta_m$ and surrounded on both sides with 3D fluid domains of viscosity $ \eta_f$ . The momentum transfer from the interfacial flows to the surrounding fluids occurs over length $ \ell_0=\eta_m/\eta_f$ , known as Saffman-Delbrück length. We use zeroth, first and second moments of Smoluchowski equation to obtain the conservation equations for concentration, polar order and nematic order fields, and use linear stability analysis and continuum simulations to study the dynamic variations of these fields as a function of $ L/\ell_0$ , the ratio of active to thermal stresses, and the dimensionless self-propulsion velocity of the embedded particles. We find that at sufficiently large activities, the suspensions of active extensile stress (pusher) with no directed motion undergo a finite wavelength nematic ordering, with the length of the ordered domains decreasing with increasing $ L/\ell_0$ . The ordering transition is hindered with further increases in $ L/\ell_0$ . In contrast, the suspensions with active contractile stress (puller) remain uniform with variations of activity. We notice that the self-propulsion velocity results in significant concentration fluctuations and changes in the size of the order domains that depend on $ L/\ell_0$ . Our research highlights the role of hydrodynamic interactions in the self-organization of active inclusions on biological interfaces.
Soft Condensed Matter (cond-mat.soft)
Superradiance Enhanced Light-Matter Interaction in Spatially Ordered Shape and Volume Controlled Single Quantum Dots: Enabling On-Chip Photonic Networks
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Lucas Jordao, Qi Huang, Swarnabha Chattaraj, Siyuan Lu, Jiefei Zhang, Anupam Madhukar
On-chip photonic networks require adequately spatially ordered matter-photon interconversion qubit sources with emission figures-of-merit exceeding the requirements that would enable the desired functional response of the network. The mesa-top single quantum dots (MTSQDs) have recently been demonstrated to meet these requirements. The substrate-encoded size-reducing epitaxy (SESRE) approach underpinning the realization of these quantum emitters allows control on the shape, size, and strain (lattice-matched or mismatched) of these epitaxial single quantum dots. We have exploited this unique feature of the MTSQDs to reproducibly create arrays of quantum dots that exhibit single photon superradiance, characteristic of a delicate balance between the confinement potential volume, depth, and the resulting binding energy of the center of mass motion of the exciton and the exciton binding energy. In the exciton’s weak confinement regime, direct enhancement of the quantum dot oscillator strength to ~30 is demonstrated for emitters in large arrays. Our findings provide compelling incentive for investigations of the potential of SESRE based tailored MTSQDs of lattice matched and mismatched material combinations for fabricating and studying interconnected networks enabled by these unique matter qubit-light qubit interconversion units.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
24 pages, 4 figures
Observation of returning Thouless pumping
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Zheyu Cheng, Sijie Yue, Yang Long, Wentao Xie, Zixuan Yu, Hau Tian Teo, Y. X. Zhao, Haoran Xue, Baile Zhang
Introduced by David Thouless in 1983, Thouless pumping exemplifies topological properties in topological systems, where the transported charge is quantized by the Chern number. Recently, returning Thouless pumping was theoretically proposed, in which quantized charge is pumped during the first half of the cycle but returns to zero in the second half. This mechanism leads to crystalline symmetry-protected delicate topological insulators. Unlike conventional topological bands, a delicate topological band is Wannierizable but not atomically obstructed, which features multicellular Wannier functions extending beyond a single unit cell. Here, by replacing the second dimension with a synthetic dimension, we realize a two-dimensional delicate topological insulator via a set of one-dimensional acoustic crystals with fine-tuned geometric parameters. Through acoustic bands and wavefunction measurements, we directly observe returning Thouless pumping and symmetric multicellular Wannier functions, followed by establishing the bulk-boundary correspondence between sub-Brillouin zone Chern numbers and gapless boundary modes. As enriched by crystalline symmetries, our experimental demonstration of returning Thouless pumping expands the current understanding of topological phases of matter.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Classical Physics (physics.class-ph)
7 pages, 3 figures
Electroforming Kinetics in HfOx/Ti RRAM: Mechanisms Behind Compositional and Thermal Engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Manasa Kaniselvan, Kevin Portner, Donato Francesco Falcone, Valeria Bragaglia, Jente Clarysse, Laura Bégon-Lours, Marko Mladenović, Bert J. Offrein, Mathieu Luisier
A critical issue affecting filamentary resistive random access memory (RRAM) cells is the requirement of high voltages during electroforming. Reducing the magnitude of these voltages is of significant interest, as it ensures compatibility with Complementary Metal-Oxide-Semiconductor (CMOS) technologies. Previous studies have identified that changing the initial stoichiometry of the switching layer and/or implementing thermal engineering approaches has an influence over the electroforming voltage magnitude, but the exact mechanisms remain unclear. Here, we develop an understanding of how these mechanisms work within a standard a-HfO$ _x$ /Ti RRAM stack through combining atomistic driven-Kinetic Monte Carlo (d-KMC) simulations with experimental data. By performing device-scale simulations at atomistic resolution, we can precisely model the movements of point defects under applied biases in structurally inhomogeneous materials, which allows us to not only capture finite-size effects but also to understand how conductive filaments grow under different electroforming conditions. Doing atomistic simulations at the device-level also enables us to link simulations of the mechanisms behind conductive filament formation with trends in experimental data with the same material stack. We identify a transition from primarily vertical to lateral ion movement dominating the filamentary growth process in sub-stoichiometric oxides, and differentiate the influence of global and local heating on the morphology of the formed filaments. These different filamentary structures have implications for the dynamic range exhibited by formed devices in subsequent SET/RESET operations. Overall, our results unify the complex ion dynamics in technologically relevant HfO$ _x$ /Ti-based stacks, and provide guidelines that can be leveraged when fabricating devices.
Materials Science (cond-mat.mtrl-sci)
Magnetization Dependent In-plane Anomalous Hall Effect in a Low-dimensional System
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
I-Hsuan Kao, Ravi Kumar Bandapelli, Zhenhong Cui, Shuchen Zhang, Jian Tang, Tiema Qian, Souvik Sasmal, Aalok Tiwari, Mei-Tung Chen, Rahul Rao, Jiahan Li, James H. Edgar, Kenji Watanabe, Takashi Taniguchi, Ni Ni, Su-Yang Xu, Qiong Ma, Shubhayu Chatterjee, Jyoti Katoch, Simranjeet Singh
Anomalous Hall Effect (AHE) response in magnetic systems is typically proportional to an out-of-plane magnetization component because of the restriction imposed by system symmetries, which demands that the magnetization, applied electric field, and induced Hall current are mutually orthogonal to each other. Here, we report experimental realization of an unconventional form of AHE in a low-dimensional heterostructure, wherein the Hall response is not only proportional to the out-of-plane magnetization component but also to the in-plane magnetization component. By interfacing a low-symmetry topological semimetal (TaIrTe4) with the ferromagnetic insulator (Cr2Ge2Te6), we create a low-dimensional magnetic system, where only one mirror symmetry is preserved. We show that as long as the magnetization has a finite component in the mirror plane, this last mirror symmetry is broken, allowing the emergence of an AHE signal proportional to in-plane magnetization. Our experiments, conducted on multiple devices, reveal a gate-voltage-dependent AHE response, suggesting that the underlying mechanisms responsible for the Hall effect in our system can be tuned via electrostatic gating. A minimal microscopic model constrained by the symmetry of the heterostructure shows that both interfacial spin-orbit coupling and time-reversal symmetry breaking via the exchange interaction from magnetization are responsible for the emergence of the in-plane AHE. Our work highlights the importance of system symmetries and exchange interaction in low-dimensional heterostructures for designing novel and tunable Hall effects in layered quantum systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Geometric Quantum Thermodynamic Engine under an Isothermal Operation: An Application of a Thouless Pumping
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-13 20:00 EDT
Ryosuke Yoshii, Hisao Hayakawa
We present a geometric formalism for the non-equilibrium thermodynamics of a small system coupled to external isothermal reservoirs as an application of Thouless pumping, where the electrochemical potentials of the reservoirs and parameters in the system’s Hamiltonian are adiabatically controlled. By analyzing the quantum master equation for the Anderson model of a quantum dot under the wide-band approximation, we obtain the work and effective efficiency of the thermodynamic engine as functions of the phase difference between the externally controlled electrochemical potentials after the system reaches a geometric cyclic state. Since the entropy production is negligible in adiabatic operations, the process we consider is reversible, analogous to the Carnot cycle.
Statistical Mechanics (cond-mat.stat-mech)
23 pages, 10 figures. arXiv admin note: substantial text overlap with arXiv:2112.12370
Eigenstate Thermalization Hypothesis correlations via non-linear Hydrodynamics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-13 20:00 EDT
Jiaozi Wang, Ruchira Mishra, Tian-Hua Yang, Luca V. Delacrétaz, Silvia Pappalardi
The thermalizing dynamics of many-body systems is often described through the lens of the Eigenstate Thermalization Hypothesis (ETH).
ETH postulates that the statistical properties of observables, when expressed in the energy eigenbasis, are described by smooth functions,
that also describe correlations among the matrix elements. However, the form of these functions is usually left undetermined. In this work, we investigate the structure of such smooth functions by focusing on their Fourier transform, recently identified as free cumulants. Using non-linear hydrodynamics, we provide a prediction for the late-time behavior of time-ordered free cumulants in the thermodynamic limit. The prediction is further corroborated by large-scale numerical simulations of a non-integrable spin-$ 1$ Ising model, which exhibits diffusive transport behavior. Good agreement is observed in both infinite and finite-temperature regimes and for a collection of local observables. Our results indicate that the smooth multi-point correlation functions within the ETH framework admit a universal hydrodynamic description at low frequencies.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
12 pages, 9 figures
Ultraslow Growth of Domains in a Random-Field System With Correlated Disorder
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-13 20:00 EDT
Subhanker Howlader, Prasenjit Das, Manoj Kumar
We study domain growth kinetics in a random-field system in the presence of a spatially correlated disorder $ h_{i}(\vec r)$ after an instantaneous quench at a finite temperature $ T$ from a random initial state corresponding to $ T=\infty$ . The correlated disorder field $ h_{i}(\vec r)$ arises due to the presence of magnetic impurities, decaying spatially in a power-law fashion. We use Glauber spin-flip dynamics to simulate the kinetics at the microscopic level. The system evolves via the formation of ordered magnetic domains. We characterize the morphology of domains using the equal-time correlation function $ C(r,t)$ and structure factor $ S(k,t)$ . In the large-$ k$ limit, $ S(k, t)$ obeys Porod’s law: $ S(k, t)\sim k^{-(d+1)}$ . The average domain size $ L(t)$ asymptotically follows \textit{double logarithmic growth behavior}.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn)
17 Pages, 10 Figures, Accepted in Physica A
Determining Linker Ratios of Mixed Metal-Organic Frameworks via Magnetic Susceptibility Measurements
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Na Du, Miao Miao Zhao, Xintian Wang, Yan Zhao, Yang Yang, Yu Ying Zhu, Ruo Tong Wang, Peng Ren, Fei Yen
Partial replacement of the organic linkers of metal-organic frameworks (MOFs) often optimizes their functionalities, however, accurate characterization of their molar ratios in many cases is challenging. This work presents a method of determining such linker ratios via measurements of the magnetic susceptibility of small quantities of powdered samples. The main presumption is taking the diamagnetic and paramagnetic contributions to the molar magnetic susceptibility of the two parent MOFs to be additive. To verify this, four examples are provided with commonly used MOFs to represent the cases when both parent MOFs are either paramagnetic or diamagnetic but with different linkers with the following systems: [MIL-101(Cr)-SO$ _3$ H]$ _{(1-\delta)}$ [MIL-101(Cr)-NO$ _2$ ]$ _{\delta}$ , [EuMOF]$ _{(1-\delta)}$ [EuPDCA]$ _{\delta}$ , [UiO-66-COOH]$ _{(1-\delta)}$ [UiO-66]$ _{\delta}$ and [MIL-101(Cr) F Free]$ _{(1-\delta)}$ [MIL-53(Al)]$ _{\delta}$ , where 1-$ \delta$ : $ \delta$ are the ratios to be determined. Depending on whether the systems were strictly paramagnetic, strictly diamagnetic or mixed, the experimental error of $ \delta$ ranged between 0.00002 and 0.012, respectively. We expect the presented method to be widely employed since samples only need to be in powdered form and because there is a lack of characterization tools in the area of MOF linker ratios. The presented method is also applicable to resolving the ratios of mixed ordinary paramagnetic systems as well as other types of non-magnetic composite materials such as tapes, zeolites and thin films.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Please note that equations 0, 1 and 2 in this submitted version were re-labelled to 1, 2 and 3 in the galley proofs, respectively. To appear in ACS Applied Materials & Interfaces
Neuromodulation via Krotov-Hopfield Improves Accuracy and Robustness of RBMs
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-13 20:00 EDT
Başer Tambaş, A. Levent Subaşı, Alkan Kabakçıoğlu
In biological systems, neuromodulation tunes synaptic plasticity based on the internal state of the organism, complementing stimulus-driven Hebbian learning. The algorithm recently proposed by Krotov and Hopfield \cite{krotov_2019} can be utilized to mirror this process in artificial neural networks, where its built-in intra-layer competition and selective inhibition of synaptic updates offer a cost-effective remedy for the lack of lateral connections through a simplified attention mechanism. We demonstrate that KH-modulated RBMs outperform standard (shallow) RBMs in both reconstruction and classification tasks, offering a superior trade-off between generalization performance and model size, with the additional benefit of robustness to weight initialization as well as to overfitting during training.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Submitted for publication
Spontaneous Enhancement of Dzyaloshinskii-Moriya Interaction via Field-Cooling-Induced Interface Engineering in 2D van der Waals Ferromagnetic ternary Tellurides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Shian Xia, Yan Luo, Iftikhar Ahmed Malik, Xinyi Zhou, Keying Han, Yue Sun, Haoyun Lin, Hanqing Shi, Yingchun Cheng, Vanessa Li Zhang, Yi Du, Sheng Liu, Chao Zhu, Ting Yu
The emergence of two-dimensional (2D) van der Waals (vdW) ferromagnets has opened new avenues for exploring topological spin textures and their applications in next-generation spintronics. Among these materials, Fe3GaTe2 (FGaT) emerges as a model system due to its room-temperature skyrmion phases, which are stabilized by strong Dzyaloshinskii-Moriya interaction (DMI). However, the atomistic origins of DMI in centrosymmetric vdW lattices remain elusive. Here, we report a spontaneous DMI enhancement mechanism driven by FC in FGaT and its analog Fe3GeTe2 (FGeT). Combining Raman spectroscopy and scanning transmission electron microscopy (STEM), we have observed the irreversible precipitation of FeTe2 in annealed FGaT. The resulting FeTe2/FGaT heterostructure is considered to break the symmetry and significantly enhance the DMI. Furthermore, similar phenomenon has been observed in the family ferromagnetic material FGeT as well. Additionally, the precipitation of FeTe2 varies significantly with different thicknesses of FGaT, aligning closely with the reported behavior of skyrmions. This discovery provides new insights into the mechanisms behind the origin of the DMI in ternary tellurides, paving the way for advanced spintronic applications.
Materials Science (cond-mat.mtrl-sci)
Strong Crystalline Thermal Insulating Induced by Extended Antibonding States
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Ruihuan Cheng, Chen Wang, Niuchang Ouyang, Xingchen Shen, Yue Chen
Crystalline solids with extreme insulation often exhibit a plateau or even an upward-sloping tail in thermal conductivity above room temperature. Herein, we synthesized a crystalline material AgTl$ _2$ I$ _3$ with an exceptionally low thermal conductivity of 0.21 $ \rm W m^{-1} K^{-1}$ at 300 K, which continues to decrease to 0.17 $ \rm W m^{-1} K^{-1}$ at 523 K. We adopted an integrated experimental and theoretical approach to reveal the lattice dynamics and thermal transport properties of AgTl$ _2$ I$ _3$ . Our results suggest that the Ag-I polyhedron enables extended antibonding states to weaken the chemical bonding, fostering strong lattice anharmonicity driven by the rattling vibrations of Ag atoms and causing lattice softening. Experimental measurements further corroborate the large atomic thermal motions and low sound velocity. These features impede particle-like phonon propagation, and significantly diminish the contribution of wave-like phonon tunneling. This work highlights a strategy for designing thermal insulating materials by leveraging crystal structure and chemical bonding, providing a pathway for advancing the development of thermal insulators.
Materials Science (cond-mat.mtrl-sci)
Surface hopping simulations show valley depolarization driven by exciton-phonon resonance
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Monolayer MoS$ _2$ has long served as a prototypical material exhibiting valleytronic behavior, yet it remains unclear exactly how phonons induce a valley depolarization of its excitonic states. Here, we apply a mixed quantum–classical simulation framework to study the phonon-induced mechanisms affecting valley polarization at short times. Our framework combines reciprocal-space surface hopping with microscopic models of the quasiparticle band structure as well as the electron-hole and carrier-phonon interactions, parametrized against ab initio calculations, while retaining explicit information on transient phonon occupancies. By means of such occupancies, our simulations show a resonance between the lowest exciton band and the dominant optical phonon branch to largely drive valley depolarization, by activating a Maialle-Silva-Sham mechanism. Resulting valley polarization times are consistent with experimental measurements across temperatures.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph), Quantum Physics (quant-ph)
9 pages, 5 figures
Driving electronic features of twisted bilayer zigzag-graphene nanoribbons
New Submission | Other Condensed Matter (cond-mat.other) | 2025-05-13 20:00 EDT
Kevin J. U. Vidarte, A. B. Felix, A. Latgé
Novel physical properties have been reported recently by stacking graphene-like systems in different configurations. Here, we explore the nature of emergent localized states at the edges of twisted bilayer graphene nanoribbons. Based on an extended tight-binding Hamiltonian, which includes hopping energy within a wide atomic neighborhood, we investigate the nature of the electronic states responsible for the transport along the four graphene nanoribbon terminals. The emphasis is on discussing the role of the stacking region symmetries, the twisted angle between the crossed zigzag nanoribbons, and also the width of the ribbons in the electronic and transport responses of the four terminals. Our findings show a direct connection between the number of non-equivalent sites on the edge of the stacking region and the localized states, in accordance with reported scanning tunneling spectroscopy measurements. Within the parameters explored, the twist angle was revealed to be the most powerful tool to control transport responses in the investigated 4-terminal devices, including special electronic beam splitter phenomena.
Other Condensed Matter (cond-mat.other)
Excitons in fractionally-filled moiré superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Junghwan Kim, Hanan Dery, Dinh Van Tuan
Long-range Coulomb forces give rise to correlated insulating states when charge particles populate a moiré superlattice at certain fractional filling factors. Such behavior is characterized by a broken translation symmetry wherein particles spontaneously form a Wigner crystal. Focusing on the experimental findings of Xu et al. [Nature \textbf{587}, 214 (2020)], we present a theory that captures the correlated insulating state of a fractionally-filled moiré superlattice through the energy shift and change in oscillator strength of the exciton absorption resonance. The theory shows that the experimental findings can only be supported if the electrons reside in a charge-ordered state (i.e., electrons are not randomly distributed among the sites of the moiré superlattice). Furthermore, we explain why the energy shifts of exciton resonances are qualitatively different in cases that the superlattice is nearly empty compared with a superlattice whose sites are doubly occupied.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Excited-State Trions in a Quantum Well
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Sourabh Jain, Mikhail Glazov, Ashish Arora
We report on the observation of an excited 2s state of a trion in a 4.2 nm wide doped GaAs/Al(0.3)Ga(0.7)As quantum well (QW) using magneto-optical Kerr effect (MOKE) spectroscopy under out-of-plane magnetic fields up to 6 T. This resonance appears slightly below the 2s exciton in energy. Strikingly, the 2s trion is found to be bound only for magnetic fields larger than 1 T. The signature of the 2s trion is absent in the magneto-reflectance spectra, while it is detectable in the MOKE spectra signifying the importance of the powerful technique. Similar to the 1s states, the 2s trion shows an opposite degree of magnetic-field-induced polarization compared to its exciton counterpart, in agreement with our theoretical calculations. This transfer of oscillator strength between the complexes establishes an optical fingerprint of the 2s excited trion.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages and 5 figures in the main manuscript file, 2 pages and 2 figures in the supplementary materials
Probing quantum phase transition in a staggered Bosonic Kitaev chain via layer-resolved localization-delocalization transition
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-13 20:00 EDT
The bosonic statistics, which allow for macroscopic multi-occupancy of single-particle states, pose significant challenges for analyzing quantum phase transitions in interacting bosonic systems, both analytically and numerically. In this work, we systematically investigate the non-Hermitian Bloch core matrix of a Hermitian staggered bosonic Kitaev chain, formulated within the Nambu framework. We derive explicit analytic conditions for the emergence of exceptional points (EPs) in the $ 4\times 4$ Bloch core matrix, with each EP marking the onset of complex-conjugate eigenvalue pairs. By mapping the full many-body Hamiltonian onto an effective tight-binding network in Fock-space and introducing layer-resolved inverse participation ratio, we demonstrate that these EPs coincide precisely with sharp localization–delocalization transitions of collective eigenstates. Comprehensive numerical analyses across hopping amplitudes, pairing strengths, and on-site potentials confirm that the EP of effective Hamiltonian universally capture the global many-body phase boundaries. Our results establish an analytically tractable, EP-based criterion for detecting critical behavior in interacting bosonic lattices, with direct relevance to photonic and cold-atom experimental platforms.
Quantum Gases (cond-mat.quant-gas), Superconductivity (cond-mat.supr-con)
Ab-initio density-matrix approach to exciton coherence: phonon scattering, Coulomb interactions and radiative recombination
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Tomer Amit, Guy Vosco, Mauro Del Ben, Sivan Refaely-Abramson
Relaxation processes following light excitation in semiconductors are key in materials-based quantum technology applications. These processes are broadly studied in atomically thin transition metal dichalcogenides (TMDs), quasi-two-dimensional excitonic semiconductors in which atomistic design allows for tunable excited-state properties, such as relaxation lifetimes and photo-induced coherence. In this work, we present a density-matrix-based approach to compute exciton relaxation within a many-body ab initio perspective. We expand our previously developed Lindblad density-matrix formalism to capture multi-channel electron-hole pair relaxation processes, including phonon and Coulomb scattering as well as radiative recombination, and study their effect on the time-resolved excited-state propagation. Using monolayer MoSe$ _2$ as a prototypical example, we examine many-body effects on the time-dependent dynamics of photoactive excitations, exploring how the electron-hole pair interactions are reflected in variations of the excitation energy, spectral signature, and state coherence. Our method supplies a detailed understanding of exciton relaxation mechanisms in realistic materials, offering a previously unexplored pathway to study excited-state dynamics in semiconductors from first principles.
Materials Science (cond-mat.mtrl-sci)
Temperature chaos may emerge many thermodynamic states in spin glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-13 20:00 EDT
We present a large-scale simulation of the three-dimensional and mean-field spin glasses down to a very low but finite temperature. We extrapolate pertinent observables, e.g., the disorder-averaged central weight to zero temperature, finding that many thermodynamic states at a finite temperature and two ground states at zero temperature are fully compatible. While the disorder-averaged central weight monotonically decreases with decreasing temperature, this is far from true for individual samples. This motivates us to link this behaviour with the well-known temperature chaos. At an observing temperature, a sample may or may not have pure state coexistence depending on whether it is undergoing temperature chaos, which is a random process. Therefore, temperature chaos is likely responsible for the emergence of many pure states, providing a natural and intuitive explanation for the coexistence of expensive domain-wall excitations and many pure states at the disorder-averaged level.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
7 pages, 3 figures
Estimating critical disorder strength of an AAH system via thermal response
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Sanchita Nandi, Santanu K. Maiti
The Aubry-André-Harper (AAH) model provides a paradigmatic platform to study localization phenomena, where a transition from a conducting to an insulating phase occurs at a critical disorder strength equal to twice the nearest-neighbor hopping amplitude, $ 2t$ . While this transition has been explored extensively through various probes, here we propose a fundamentally new approach based on thermal response. Specifically, we demonstrate that the electronic specific heat exhibits a distinctive signature across the transition, directly reflecting the anomalous evolution of the density of states with disorder strength. Our findings, supported by numerical analysis, establish specific heat measurement as a powerful and sensitive probe for detecting the critical point. This thermal characterization opens a new avenue for exploring disorder-induced phase transitions and paves the way for experimental realization in engineered quantum systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn)
5 pages, 6 figures (comments are welcome)
Fermi liquid theory of $d$-wave altermagnets: demon modes and Fano-demon states
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Habib Rostami, Johannes Hofmann
We develop a Fermi liquid theory of $ d$ -wave altermagnets and apply it to describe their collective excitation spectrum. We predict that in addition to a conventional undamped plasmon mode, where both spin components oscillate in phase, there is an acoustic plasmon (or {\em demon}) mode with out-of-phase spin dynamics. By analyzing the dynamical structure factor, we reveal a strong dependence of the demon’s frequency and spectral weight both on the Landau parameters and on the direction of propagation. Notably, as a function of the propagation angle, we show that the acoustic mode evolves from a {\em hidden state}, which has zero spectral weight in the density excitation spectrum, to a weakly damped propagating demon mode and then to a {\em Fano-demon mixed state}, which is marked by a strong hybridization with particle-hole excitations and a corresponding asymmetric line shape in the structure factor. Our study paves the way for applications of altermagnetic materials in opto-spintronics by harnessing itinerant electron spin oscillations beyond traditional magnon spin waves.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 3 figures
Hydrogen-rich hydrate at high pressures up to 104 GPa
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Alexander F. Goncharov, Elena Bykova, Iskander Batyrev, Maxim Bykov, Eric Edmund, Amol Karandikar, Mahmood Mohammad, Stella Chariton, Vitali Prakapenka, Konstantin Glazyrin, Mohamed Mezouar, Gaston Garbarino, Jonathan Wright
Gas hydrates are considered fundamental building blocks of giant icy planets like Neptune and similar exoplanets. The existence of these materials in the interiors of giant icy planets, which are subject to high pressures and temperatures, depends on their stability relative to their constituent components. In this study, we reexamine the structural stability and hydrogen content of hydrogen hydrates, (H2O)(H2)n, up to 104 GPa, focusing on hydrogen-rich materials. Using synchrotron single-crystal X-ray diffraction, Raman spectroscopy, and first-principles theoretical calculations, we find that the C2-filled ice phase undergoes a transformation to C3-filled ice phase over a broad pressure range of 47 - 104 GPa at room temperature. The C3 phase contains twice as much molecular H2 as the C2 phase. Heating the C2-filled ice above approximately 1500 K induces the transition to the C3 phase at pressures as low as 47 GPa. Upon decompression, this phase remains metastable down to 40 GPa. These findings establish new stability limits for hydrates, with implications for hydrogen storage and the interiors of planetary bodies.
Materials Science (cond-mat.mtrl-sci), Earth and Planetary Astrophysics (astro-ph.EP)
14 pages, 10 figs., 1 table. Supplementary information
Regimes of optical transparency and instabilities of collinear dielectric ferromagnetic materials in the presence of the dynamic magnetoelectric effect
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
The contribution of the polarization associated with the noncollinear parts of spins in the dielectric permeability tensor of multiferroic materials is considered. As the equilibrium state, we consider the systems of parallel spins, so we have zero equilibrium polarization. Dynamical polarization appears due to the spin evolution via the magnetoelectric coupling. The regime of frequencies, where the refractive index goes to 1 is found for the high (in comparison with the characteristic frequency of the anisotropic energy or the cyclotron frequency) left/right circularly polarized electromagnetic wave propagating parallel to the equilibrium spin direction. Moreover, the signs of the imaginary part of the dielectric permeability, the refractive index, and the frequency show the instability of the parallel spin configuration at the propagation of the linearly polarized electromagnetic wave due to the effective magnetoelectric interaction.
Materials Science (cond-mat.mtrl-sci)
7 pages
Buckling of residually stressed cylindrical tubes under compression
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Tao Zhang, Luis Dorfmann, Yang Liu
We evaluate the loss of stability of axially compressed slender and thick-walled tubes subject to a residual stress distribution. The nonlinear theory of elasticity, when used to analyze the underlying deformation, shows that the residual stress induces preferred directions in the reference configuration. The incremental theory, given in Stroh form, is used to derive an exact bifurcation condition. The critical stretch and the associated critical buckling mode are identified for axisymmetric and asymmetric increments in the deformation. Mode transitions are illustrated as the tube slenderness varies. For slender tubes, Euler buckling is energetically favorable, and the effect of residual stress is negligible. However, for short and thick-walled tubes where barreling mode is dominant, the residual stress significantly affects the buckling behavior and may eliminate barreling instability. We show that, depending on its magnitude and direction, residual stress can either accelerate or delay instability. Phase diagrams for various modes are obtained and provide insight into pattern selection across different tube geometries.
Soft Condensed Matter (cond-mat.soft)
24 pages, 12 figures
Stabilization of the skyrmion in a hybrid magnetic-superconducting nanostucture
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Julia Kharlan, Mateusz Zelent, Konstantin Guslienko, Vladimir O. Golub, Jaroslaw W. Klos
Stabilization of skyrmions in a magnetic material without the Dzyaloshinskii-Moriya exchange interaction requires using of an inhomogeneous magnetic field, such as a demagnetization field or an Oersted field. To control and tune the local magnetic field in magnetic material we propose to exploit superconducting nanorings. The field stabilizes the skyrmion through the presence of persistent current induced by the pulses of external field. We analyze the conditions for the stabilization of Neel skyrmion in ferromagnetic layers with out-of-plane anisotropy, as a function of the nanoring size and induced superconducting current. We show that the superconducting current should exceed a critical value for the skyrmion to become stable. The paper presents consistent results from both analytical and micromagnetic calculations for Co and Ga:YIG thin magnetic films.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 4 figures. Additionally supplementary materials 2 pages, 2 figures
Optimizing spin polarization in quantum dot vertical-gain structures through pump wavelength selection
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Najm Alhosiny, Sami S. Alharthi, J. Doogan, E. Clarke, T. Ackemann
Spintronic applications require an efficient injection of spin-polarized carriers. We study the maximally achievable spin polarization in InAs quantum dots in a vertical-cavity gain structure to be used in telecoms-wavelength vertical-external-cavity surface-emitting lasers via measurement of the Stokes parameter of the photoluminescence emission around 1290 nm. Using five pump wavelengths between 850 and 1070 nm, the observed spin polarization depends strongly on the pump wavelength with the highest polarization of nearly 5% found for excitation at 980 nm. This corresponds to an effective spin lifetime of 40 ps and is attributed to the dominant excitation of heavy holes only.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
12 pages, 4 figures. The following article has been accepted by Applied Physics Letters
Unified theory of photovoltaic Hall effect by field- and light-induced Berry curvatures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Yuta Murotani, Tomohiro Fujimoto, Ryusuke Matsunaga
Photovoltaic Hall effect is an interesting platform of Berry curvature engineering by external fields. Floquet engineering aims at generation of light-induced Berry curvature associated with topological phase transition in solids, which may manifest itself as a light-induced anomalous Hall effect. However, recent studies have pointed out an important role of the bias electric field, which adds a field-induced circular photogalvanic effect to the photovoltaic Hall effect. Except for numerical studies, the two mechanisms have been described by different theoretical frameworks, hindering a coherent understanding. Here, we develop a unified theory of the photovoltaic Hall effect capable of describing both mechanisms on an equal footing. We reveal that the bias electric field alters the interband transition dipole moment, transition energy, and intraband velocity, all contributing to the field-induced circular photogalvanic effect in nonmagnetic materials. The first process can be expressed as a manifestation of the electric field-induced Berry curvature. Shift vector plays an essential role in determining the transition energy shift. We also clearly distinguish the anomalous Hall effect by light-dressed states within the density matrix calculation using the length gauge. Our theory unifies a number of nonlinear optical processes in a physically transparent way and reveals their geometric aspect.
Materials Science (cond-mat.mtrl-sci)
25 pages, 4 figures
Growth of ultra-clean single crystals of RuO2
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Shubhankar Paul, Giordano Mattoni, Hisakazu Matsuki, Thomas Johnson, Chanchal Sow, Shingo Yonezawa, Yoshiteru Maeno
We report the details of the growth of ultra-clean single crystals for RuO2, a candidate material for altermagnetism. By using a crystal-growth tube with a necking structure and precisely controlling the conditions of the sublimation transport method, it is possible to control the morphology of the crystals. We obtained crystals in mainly three kinds of morphology: thick plate-like crystals typically 5 x 3 x 2mm3 and up to 10 x 5 x 2mm3 with a large (101) facet, rhombohedral columnar crystals elongating along the [001] direction, and fiber and needle crystals of length up to 8 mm and the width of 0.1-0.4 mm. These crystals show residual resistivity of about 30 nOhmcm and a residual resistivity ratio (RRR) up to 1200. The crystals do not exhibit any signs of magnetic ordering down to low temperatures.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Quantum spin excitations in a dual-core magnetic molecule
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Wenbin Li (1), Wenwen Shi (2), Xiaoxiao Xiao (3), Haiyan Zhu (4), Cai Cheng (5 and 6), Dongfei Wang (7), Lan Chen (8 and 9), Masahiro Haze (1), Huixia Fu (4), Xiao Zheng (10), Yang Guo (11), Zhendong Li (3), Yukio Hasegawa (1)
Magnetic excitations are important quantum phenomena in magnetic systems and have been widely studied in individual magnetic atoms and molecules as well as their assembled structures over the past few decades. Using scanning tunneling microscopy/spectroscopy (STM/S) combined with density functional theory (DFT) and the state-of-the-art ab initio wavefunction calculations, we investigated the properties of a novel dual-core Cr2Br6 molecule, which consists of two Cr ions coupled via superexchange through a single near-90° Cr-Br-Cr scissors bond. Under zero magnetic field, we observed a Fano peak with multi-steps through STS. When an external magnetic field is applied, some steps exhibit additional splitting, while others change little. We find that the Cr2Br6, exhibits a spin-degenerate ground state, and the complex peak splitting arises from the coexistence of vibrational and magnetic excitations in the molecule. Our results reveal rich quantum spin behavior in a well-defined two-core magnetic trihalide complex at the atomic scale, offering not only a minimal model for superexchange-coupled multi-spin quantum excitations but also a possible foundational unit for future molecule-based quantum functionalities.
Materials Science (cond-mat.mtrl-sci), Atomic and Molecular Clusters (physics.atm-clus)
18 pages, 3 figues and 2 tables
Generation of magnetic chiral solitons, skyrmions, and hedgehogs with electric fields
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Teruya Nakagawara, Minoru Kanega, Shunsuke C. Furuya, Masahiro Sato
Electric-field controls of Dzyaloshinskii-Moriya interactions (DMIs) have recently been discussed from the microscopic viewpoint. Since the DMI plays a critical role in generating topological spin textures (TSTs) such as the chiral soliton, the magnetic skyrmion, and the magnetic hedgehog, electric-field controls of these TSTs have become an important issue. This paper shows that such electric-field-induced DMI indeed creates and annihilates TSTs by numerically solving the Landau-Lifshitz-Gilbert (LLG) equation for many-body spin systems at finite temperatures. We show that when a strong electric field is applied in a proper way to one- or two-dimensional ferromagnets, the Hamiltonians are changed into the well-known spin models for the chiral soliton or the skyrmion lattice, and the TST states emerge. We utilize a machine-learning method to count the number of generated TSTs. In the three-dimensional (3D) case, we demonstrate the electric-field induction of a magnetic hedgehog structure as follows: Applying a strong enough electric field along a proper direction to a skyrmion-string state (a triple-$ \boldsymbol{q}$ state) at low but finite temperatures, we find that the field-induced DMI can drive a quadruple-$ \boldsymbol{q}$ state with hedgehog-antihedgehog pairs. This result indicates that we have succeeded in constructing a simple 3D short-range interacting spin model hosting a magnetic hedgehog structure.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
Pseudo-Goldstone Modes at Finite Temperature
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Goldstone’s theorem and its extension to pseudo-Goldstone (PG) modes have profound implications across diverse areas of physics, from quantum chromodynamics to quantum magnetism. PG modes emerge from accidental degeneracies lifted by quantum and thermal fluctuations, leading to a finite gap–a phenomenon known as “order by disorder.” In this paper, we derive a general curvature formula for the PG gap at finite temperature, applicable to both collinear (e.g., ferromagnets and anti-ferromagnets) and noncollinear magnetic orders (e.g., coplanar orders in frustrated magnetic systems). After validating our formula against known models, we apply it to the XXZ model on the triangular lattice, which hosts coplanar magnetic orders in equilibrium and is relevant to materials such as Na2BaCo(PO4)2 and K2Co(SeO3)2, known for their supersolid phases and giant magnetocaloric effects. Our results reveal a distinct scaling behavior: a linear decrease of the PG gap with temperature, driven by entropy effects from magnon scattering across multiple bands. This stands in stark contrast to the high-temperature scaling recently proposed for systems with a single magnon band. This work establishes a general framework for investigating PG modes at finite temperatures and opens an avenue to explore rich quantum phases and dynamics in frustrated systems with noncollinear magnetic orders.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Superconducting Dome and Quantum Criticality in Two-Dimensional NbO2 Triangular Lattice
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-13 20:00 EDT
Takuto Soma, Kohei Yoshimatsu, Akira Ohtomo
The emergence of superconductivity with strong correlation is one of the most attracted issues in condensed-matter physics, as seen in various unconventional superconductors. Here we show a new strongly correlated superconductor Li1-xNbO2 with rich characteristics such as two-dimensional, geometrically frustrated, and triangular NbO2 lattice and correlated flat-band-like electronic states. We revealed the electronic phase diagram by implementing Li-ion electrochemical cells with LiNbO2 epitaxial films. The Li-ion deintercalation increased the hole-doping level in NbO2 layer, along which a band insulator LiNbO2 underwent to a Fermi-liquid (FL) metal and superconductor associated with non-Fermi liquid (NFL) characters. The evolution of the NFL state coincided with the suppression of the Kondo-singlet formation near the superconducting dome, which linked superconductivity with quantum criticality. The obtained phase diagram involves general aspects of strongly correlated superconductors and bridges the gap between various systems.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 4 figures
Topological surface states induced by magnetic proximity effect in narrow-gap semiconductor alpha-Sn
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Soichiro Fukuoka, Le Duc Anh, Masayuki Ishida, Tomoki Hotta, Takahiro Chiba, Yohei Kota, Masaaki Tanaka
The combination of magnetism and topological properties in one material platform is attracting significant attention due to the potential of realizing low power consumption and error-robust electronic devices. Common practice is to start from a topological material with band inversion and incorporates ferromagnetism via chemical doping or magnetic proximity effect (MPE). In this work, we show that a topological material is not necessary and that both ferromagnetism and band inversion can be established simultaneously in a trivial insulating material by MPE from a neighbouring ferromagnetic layer. This novel route is demonstrated using quantum transport measurements and first principles calculations in a heterostructure consisting of 5 nm thick FeOx/1 monolayer of FeAs/ 3 nm thick alpha Sn. The Shubnikov de Haas oscillations show that there is linear band dispersion with high mobility in the heterostructure even though a 3 nm thick alpha Sn single layer is a trivial semiconductor. Furthermore, first principles calculations reveal that band inversion indeed occurs in this heterostructure, suggesting that the observed linear band is a topological surface state within this inverted gap. This work significantly expands the foundation for realizing magnetic topological materials in a myriad of trivial narrow gap semiconductors.
Materials Science (cond-mat.mtrl-sci)
Interplay between timescales governs the residual activity of a harmonically bound active Brownian particle
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Active microparticles in confining potentials manifest complex and intriguing dynamical phenomena, as their activity competes with confinement. The steady-state position distributions of harmonically bound active Brownian particles (HBABPs) exhibit a crossover from Boltzmann-like to bimodal, commonly recognized as passive to active transition, upon variation of the activity and the confinement strength. By studying optically trapped phoretically active Janus colloids, along with simulations and analytical calculations of HBABPs, we provide a comprehensive dynamical description emphasizing the resultant velocity to examine this understanding. Our results establish that the crossover is instead from active to passive-like, and is governed solely by the interplay between the persistence time $ \tau_{\rm R}$ , and the equilibration time in harmonic potential $ \tau_k$ . When $ \tau_{\rm R} < \tau_k$ , despite a Boltzmann-like position distribution, the HBABP retains a substantial resultant or residual active velocity, denoting an activity-dominated regime. In contrast, at $ \tau_{\rm R} > \tau_k$ , the restoring force fully counterbalances propulsion at a radial distance, where the HBABP exhibits harmonically bound Brownian particle (HBBP)-like dynamics, and the position distribution becomes bimodal. We further provide a quantitative measure of the residual activity, which decreases monotonically with $ \tau_{\rm R} / \tau_k$ , eventually converging to a nominal value corresponding to HBBP as $ \tau_{\rm R} / \tau_k$ exceeds 1, corroborating our conclusions.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
18 pages, 5 main figures, 7 extra figures, and supplementary
Crossed pseudopotential$-$functional calculations made simple: An extended Kohn-Sham framework
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Kuiyu Ye, Jiale Shen, Haitao Liu, Yuanchang Li
Modern density-functional-theory (DFT) calculations rely heavily on pseudopotentials, yet their impact on accuracy is barely addressed. In this work, we derive from the Kohn-Sham equation that the use of pseudopotentials invariably introduces a ``dropping” error, which leads to a deviation from the Hohenberg-Kohn theorem. Crossed pseudopotential-functional calculations provide a pragmatic way to balance accuracy and efficiency, enabling the right results for the right reasons. This paradigm goes beyond the (generalized) Kohn-Sham framework, which we name the extended Kohn-Sham framework. We support our assertion with a bandgap study on 54 monovalent-Cu semiconductors. The crossed calculations, compared to consistent ones, not only remove all 11 erroneous metal predictions, but also drastically reduce the mean relative error from 80% to 20%. The accuracy even exceeds that of the hybrid functionals and GW due to the role of pseudopotentials in modelling the external potentials of Cu-valence electrons that cannot be compensated by exchange-correlation.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Current-induced Nonequilibrium Phase Transition Accompanied by Giant Gap Reduction in Vanadium Dioxide
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Akitoshi Nakano, Masato Imaizumi, Ichiro Terasaki
We investigated nonlinear conduction in bulk single crystals of VO2 with precise temperature control. Two distinct nonequilibrium phenomena were identified: a gradual reduction of the charge gap and a current-induced insulator-metal transition. The electric field required to drive the nonlinear conduction is two to three orders of magnitude smaller than that reported for VO2 thin films or nanobeams, strongly indicating an intrinsic electronic origin rather than a temperature increase due to self heating. Notably, our results suggest that the application of a steady current to the frozen insulating state can induce a nonequilibrium steady-state metallic phase – effectively melting the electronic ice. This highlights a novel route to controlling electronic states via nonthermal, current-driven mechanisms.
Strongly Correlated Electrons (cond-mat.str-el)
Nitrogen and oxygen transport and reactions during plasma nitridation of zirconium thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Luc Pichon (UP, PPrime [Poitiers]), A. Straboni, T. Girardeau, M. Drouet, P. Widmayer
Zirconium nitride (ZrN) is a refractory material with good mechanical and thermal properties. It is therefore a good candidate for hard surface treatment at high temperature. In this work, we report the growth and characterization of ZrN by plasma assisted thermal nitridation of zirconium films in a NH3 atmosphere. The process was monitored by in situ monochromatic ellipsometry and the nitrides grown were profiled and analyzed by Auger electron spectroscopy. By using temperatures in the 700–800___{\textdegree}C range, the material obtained is quite close to ZrN, but, depending on experimental conditions, residual oxygen (impurities) can be easily incorporated by reaction with zirconium. The analysis of the ellipsometric data has shown that the nitridation did not occur by simple growth of nitride on zirconium. Auger profiles confirmed the presence of an oxidized zirconium layer localized between the nitrided surface and the remaining metal. This oxidation was observed to occur preferentially during temperature ramping, that is, in the low temperature regime. At high temperature, nitridation is dominant and the incorporated oxygen is exchanged with nitrogen. Oxygen is then partly rejected by diffusion out of the film through the ZrN surface layer and partly by diffusion in the deep zirconium sublayer. By using these observations, a new model of growth with a layered ZrN/ZrOx/Zr film was used to describe in situ ellipsometric data. By comparing the pure thermal and the plasma treatments, the advantages of the plasma assisted treatment become clearly: complete nitridation of the zirconium layer was achieved and the oxygen amounts in the film were substantially reduced.
Materials Science (cond-mat.mtrl-sci)
Journal of Applied Physics, 2000, 87 (2), pp.925-932
Directional entanglement of spin-orbit locked nitrogen-vacancy centers by magnons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Zhiping Xue, Ji Zou, Chengyuan Cai, Gerrit E. W. Bauer, Tao Yu
We address that the stray magnetic field emitted by the excited quantum states of the nitrogen-vacancy (NV) centers is spin-momentum locked, such that the spin transfer to nearby ferromagnetic nanostructures is unidirectional. This may allow the controlled excitation of propagating magnons by NV centers in diamond. A pair of NV spin qubits exchange virtual magnons in a magnetic nanowire in a chiral manner that leads to directional quantum entanglement. A magnon-based ``quantum-entanglement isolator” should be a useful device in future quantum information technology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 7 figures
Nonrelativistic Piezomagnetic Effect in an Organic Altermagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Makoto Naka, Yukitoshi Motome, Tsuyoshi Miyazaki, Hitoshi Seo
We theoretically study the piezomagnetic effect on the altermagnetic state in $ \kappa$ -type molecular conductors, focusing on its nonrelativistic mechanism. By introducing shear stress as a monoclinic distortion, we evaluate variations in the effective tight-binding model using first-principles calculations. Using the derived parameters, we investigate the Hubbard model and its effective Heisenberg model on the two-dimensional (distorted) $ \kappa$ -type lattice within mean-field approximation. We show that the system exhibits the piezomagnetic effect, i.e., a net magnetization induced at finite temperatures in the undoped insulating state and both in the ground state and at finite temperatures upon doping. In a real-space picture, this uniform magnetization arises from the ferrimagnetic spin structure due to inequivalent spin sites induced by lattice distortion. Meanwhile, in a momentum-space picture, it stems from the {\it s}-wave spin splitting of the electron and magnon bands, independent of spin-orbit coupling. We find that this nonrelativistic piezomagnetism remains finite, but becomes smaller in the limit of strong dimerization where the energy gap between the bonding and antibonding orbitals is infinitely large and the {\it d}-wave altermagnetic spin splitting is absent, highlighting the importance of the multi-orbital nature.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages, 3 figures, 2 tables
Kinetic theory of point vortices at order $1/N$ and $1/N^{2}$
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-13 20:00 EDT
Jean-Baptiste Fouvry, Pierre-Henri Chavanis
We investigate the long-term relaxation of a distribution of $ N$ point vortices in two-dimensional hydrodynamics, in the limit of weak collective amplification. Placing ourselves within the limit of an average axisymmetric distribution, we stress the connections with generic long-range interacting systems, whose relaxation is described within angle-action coordinates. In particular, we emphasise the existence of two regimes of relaxation, depending on whether the system’s profile of mean angular velocity (frequency) is a non-monotonic [resp. monotonic] function of radius, which we refer to as profile (1) [resp. profile (2)]. For profile (1), relaxation occurs through two-body non-local resonant couplings, i.e. $ 1/N$ effects, as described by the inhomogeneous Landau equation. For profile (2), the impossibility of such two-body resonances submits the system to a kinetic blocking''. Relaxation is then driven by three-body couplings, i.e. $ 1/N^{2}$ effects, whose associated kinetic equation has only recently been derived. For both regimes, we compare extensively the kinetic predictions with large ensemble of direct $ N$ -body simulations. In particular, for profile (1), we explore numerically an effect akin to resonance broadening’’ close to the extremum of the angular velocity profile. Quantitative description of such subtle nonlinear effects will be the topic of future investigations.
Statistical Mechanics (cond-mat.stat-mech)
19 pages, 15 figures, submitted to APS
Variational Quantum Monte Carlo investigations of the superconducting pairing in La$_3$Ni$_2$O$_7$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-13 20:00 EDT
Yi-Qun Liu, Da Wang, Qiang-Hua Wang
We investigate the pairing symmetry in the novel superconductor La$ _3$ Ni$ 2$ O$ 7$ under pressure by the non-perturbative variational quantum Monte Carlo. Within the bilayer Hubbard model and extended $ t-J$ model with two orbitals in the $ E_g$ doublet, we find the local strong correlation triggers $ s\pm$ -wave Cooper pairing, with sign change of the gap function among the various Fermi pockets, while the $ d{x^2-y^2}$ -wave pairing is generically disfavored. This is in agreement with the results from functional renormalization group applied in the weak up to moderate correlation limit. We find the 3d$ _{3z^2-r^2}$ orbital plays a leading role in the superconducting pairing. We also demonstrate the finite intra-orbital double occupancy even in the strong correlation limit, shedding light on the itinerant versus local moment picture of the electrons in this material.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 7 figures
Unraveling the Reaction Mechanisms in a Chemically Amplified EUV Photoresist from a Combined Theoretical and Experimental Approach
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Laura Galleni, Dhirendra P. Singh, Thierry Conard, Geoffrey Pourtois, Paul van der Heide, John Petersen, Kevin M. Dorney, Michiel J. van Setten
Extreme ultraviolet (EUV) lithography has revolutionized high-volume manufacturing of nanoscale components, enabling the production of smaller, denser, and more energy efficient integrated circuit devices. Yet, the use of EUV light results in ionization driven chemistry within the imaging materials of lithography, the photoresists. The complex interplay of ionization, generation of primary and secondary electrons, and the subsequent chemical mechanisms leading to image formation in photoresists has been notoriously difficult to study. In this work, we deploy photoemission spectroscopy with a 92 eV EUV light source combined with first-principles simulations to unravel the chemical changes occurring during exposure in a model chemically amplified photoresist. The results reveal a surprising chemical reaction pathway, namely the EUV-induced breakdown of the photoacid generator (PAG), which is a critical component in the EUV mechanism. This previously unobserved reaction mechanism manifests as changes in intensity of the valence band peaks of the EUV photoemission spectrum, which are linked to degradation of the PAG via an advanced atomistic simulation framework. Our combined experimental and theoretical approach shows that EUV photoemission can simultaneously resolve chemical dynamics and the production of primary and secondary electrons, giving unique insights into the chemical transformation of photoresist materials. Our results pave the way for utilizing accessible, table-top EUV spectroscopy systems for observing EUV photoresist chemical dynamics, with the potential for time-resolved measurements of photoemission processes in the future.
Materials Science (cond-mat.mtrl-sci)
Proc. SPIE 13428, Advances in Patterning Materials and Processes XLII, 134281D (22 April 2025)
All-optical electric field sensing with nanodiamond-doped polymer thin films
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Roy Styles, Mengke Han, Toon Goris, James Partridge, Brett C. Johnson, Blanca del Rosal, Amanda N. Abraham, Heike Ebendorff-Heidepriem, Brant C. Gibson, Nikolai Dontschuk, Jean-Philippe Tetienne, Philipp Reineck
The nitrogen-vacancy (NV) center is a photoluminescent defect in diamond that exists in different charge states, NV$ ^-$ and NV$ ^0$ , that are sensitive to the NV’s nanoscale environment. Here, we show that photoluminescence (PL) from NV centers in fluorescent nanodiamonds (FNDs) can be employed for all-optical voltage sensing based on electric field-induced NV charge state modulation. More than 95% of FNDs integrated into a capacitor device show a transient increase in NV$ ^-$ PL intensity of up to 31% within 0.1 ms after application of an external voltage, accompanied by a simultaneous decrease in NV$ ^0$ PL. The change in NV$ ^-$ PL increases with increasing applied voltage from 0 to 100 V, corresponding to an electric field of 0 to 625 kV cm$ ^ {-1}$ in our devices. The electric field sensitivity of a single FND is 19 V cm$ ^{-1}$ Hz$ ^ {-1/2}$ . We investigate the NV charge state photodynamics on the millisecond timescale and find that the change in NV PL strongly depends on the rate of photoexcitation. We propose a model that qualitatively explains the observed changes in NV PL based on an electric field-induced redistribution of photoexcited electrons from substitutional nitrogen defects to NV centers, leading to a transient conversion of NV$ ^0$ to NV$ ^-$ centers upon application of an external voltage. Our results contribute to the development of FNDs as reliable, all-optical, nanoscale electric field sensors in solid-state systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Inverse Bauschinger Effect in Active Ultrastable Glasses
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Rashmi Priya, Smarajit Karmakar
Memory effects in amorphous materials have been widely studied because of their possible widespread future applications. We show here that ultrastable glasses can exhibit a transient reversible memory effect when subjected to both a local driving force via Run-and-tumble active particles and global shear. We investigate the system’s response across different yielding regimes by selectively switching the shear direction at different strains. We analyze how changes in shear direction influence yielding, post-yield behavior, and structural evolution in active amorphous solids. Our model active system exhibits an enhanced anisotropic response, displaying both conventional and inverse Bauschinger effects, depending on the deformation history. The results indicate that activity-induced shear band networks create structural memory, enabling the system to heal upon shear reversal due to the transient nature of this phenomenon. Additionally, we observe that shear softening under cyclic loading produces an irreversible, stable, and less branched network structure with increasing cycles. These findings provide novel insights into how activity and shear collectively contribute to mechanical response, including memory formation in ultrastable disordered systems.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
Charge transfer between van der Waals coupled metallic 2D layers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Bharti Matta, Philipp Rosenzweig, Craig Polley, Ulrich Starke, Kathrin Küster
Van der Waals heterostructures have become a rapidly growing field in condensed matter research, offering a platform to engineer novel quantum systems by stacking different two-dimensional (2D) materials. A diverse range of material combinations, including hexagonal boron nitride, transition metal dichalcogenides and graphene, with electronic properties spanning from insulating to semiconducting, metallic, and semimetallic, have been explored to tune the properties of these heterostacks. However, understanding the interactions and charge transfer between the stacked layers remains challenging, particularly when more than two layers are involved. In this study, we investigate the charge transfer in a potassium-adlayer/graphene/lead-monolayer heterostructure stacked on a SiC substrate. Using synchrotron-based angle-resolved photoemission spectroscopy, we analyze the band structure of each layer, focusing on the charge transfer from K to the underlying 2D layers. Since K forms a $ (2 \times 2)$ overlayer with respect to graphene, the amount of charge carriers donated by K can be determined. Our findings reveal that adsorption of K not only leads to a significant $ n$ -doping of the adjacent graphene layer but also to an electron transfer into the Pb monolayer. Remarkably, $ \approx 44%$ of the electrons donated by the K adlayer are transferred into its second nearest neighbouring layer, i.e. Pb, while $ \approx 56%$ remain in the graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Correlated electronic structure of the alternating single-layer bilayer nickelate La${5}$Ni${3}$O$_{11}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Harrison LaBollita, Antia S. Botana
The recent discovery of superconductivity under pressure in Ruddlesden-Popper (RP) nickelates has attracted a great deal of attention. Here, using density-functional theory plus dynamical mean-field theory, we study the correlated electronic structure of the latest superconducting member of the family: the alternating single-layer bilayer nickelate La$ _{5}$ Ni$ _{3}$ O$ _{11}$ . Due to its alternating single-layer and bilayer structural motif, this hybrid RP nickelate exhibits layer-selective physics with the single-layer neighboring a Mott instability, rendering the bilayer the dominant contributor to its low-energy physics, both at ambient and high pressure. The electronic structure of La$ _{5}$ Ni$ _{3}$ O$ _{11}$ ultimately resembles that of the bilayer compound La$ _{3}$ Ni$ _{2}$ O$ _{7}$ , pointing to the presence of universal features in the family of superconducting RP nickelates. Thus, La$ _{5}$ Ni$ _{3}$ O$ _{11}$ provides a new platform to disentangle the key degrees of freedom underlying superconductivity in pressurized RP nickelates, underscoring the central role of the bilayer structural motif.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 4 figures
Role of non-reciprocity in spin-wave channeling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Jean-Paul Adam, Nathalie Bardou, Aurélie Solignac, Joo-Von Kim, Thibaut Devolder
The extent to which non-reciprocal waves can be guided in arbitrary directions is an interesting question. We address one aspect of this problem by studying the propagation of acoustic spin waves in a narrow physical conduit made of a synthetic antiferromagnet. Through a combination of Brillouin Light Scattering microscopy and modeling, we demonstrate that even when attempting to guide waves in the reciprocal direction of the material, the system still exhibits strong signatures of non-reciprocity. This includes the excitation of high wavevector waves in the direction perpendicular to the intended channeling, as well as energy transfer in directions that often neither aligns with the physical conduit nor with the symmetry axes of the magnetic properties. These findings have implications for the modeling of propagating wave spectroscopy in non-reciprocal materials and their potential applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Empirical approaches to Frohlich excitonic polarons in polar semiconductors with application to 3D halide perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Jacky Even, Simon Thebaud, Aseem Kshirsagar, Laurent Pedesseau, Marios Zacharias, Claudine Katan
Short abstract: The paper reviews the physics of Frohlich excitonic polarons from the viewpoint of empirical approaches with some original developments. Models for excitonic polarons in ionic semiconductors in the spirit of the Lee Low and Pines (LLP) model for free polarons were initiated by Toyozawa and Hermanson and extended by Pollman and Buttner (PB). The dominant electron-hole interaction with the lattice introduced by Frohlich is represented by a long-range effective interaction with a single longitudinal optical polar mode. The properties of the excitonic polarons are characterized by various physical quantities such as effective dielectric constants, effective masses, virtual phonon populations, carrier self-energies and binding energies, and effective electron-hole interactions mediated by the lattice. In 3D perovskites, the excitonic polarons deviate from the simplified picture of weakly interacting (almost free) polarons, with sizeable effects of electron-hole correlations on all the physical properties.
Materials Science (cond-mat.mtrl-sci)
Integrating Machine Learning with Triboelectric Nanogenerators: Optimizing Electrode Materials and Doping Strategies for Intelligent Energy Harves
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Guanping Xu, Zirui Zhao, Zhong Lin Wang, Hai-Feng Li
The integration of machine learning techniques with triboelectric nanogenerators (TENGs) offers a transformative pathway for optimizing energy harvesting technologies. In this study, we propose a comprehensive framework that utilizes graph neural networks to predict and enhance the performance of TENG electrode materials and doping strategies. By leveraging an extensive dataset of experimental and computational results, the model effectively classifies electrode materials, predicts optimal doping ratios, and establishes robust structure-property relationships. Key findings include a 65.7% increase in energy density for aluminum-doped PTFE and an 85.7% improvement for fluorine-doped PTFE, highlighting the critical influence of doping materials and their concentrations. The model further identifies PTFE as a highly effective negative electrode material, achieving a maximum energy density of 1.12 J/cm$ ^2$ with 7% silver (Ag) doping when copper (Cu) is used as the positive electrode. This data-driven approach not only accelerates material discovery but also significantly reduces experimental costs, providing novel insights into the fundamental factors influencing TENG performance. The proposed methodology establishes a robust platform for intelligent material design, advancing the development of sustainable energy technologies and self-powered systems.
Materials Science (cond-mat.mtrl-sci)
Morphology and Strain Engineering of Cu-based Materials by Chemical Dealloying for Electrochemical CO Reduction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Yuxiang Zhou, Ayman A. El-Zoka, Oliver R. Waszkiewicz, Benjamin Bowers, Rose P. Oates, James Murawski, Anna Winiwarter, Guangmeimei Yang, Oleg Konovalov, Maciej Jankowski, Ifan E. L. Stephens, Mary P. Ryan
Nanoporous Cu (NPC), synthesized by chemical dealloying of brass, holds significant potential for catalysis of electrochemical CO2 and CO reduction, owing to the optimal binding energy of Cu with \astCO and \astH intermediates, and the abundance of surface under-coordinated atoms inherent to the nanoporous structure. However, further optimization of NPC morphology and chemistry for CO reduction can only be made possible by understanding the dealloying process. Hence overcoming challenges concerning the direct measurement of atomic scale chemistry and under-coordinated atoms in NPC nano-ligaments is vital. In this study, NPC with tunable ligament sizes between nanometer and micrometer range were synthesized by varying the temperature of Cu20Zn80 (atomic ratio) chemical dealloying in concentrated phosphoric acid. The evolution of chemistry and structure of nano-ligaments during dealloying were probed for the first time using in situ synchrotron X-ray diffraction (XRD) and cryo-atom probe tomography (APT) revealing the phase transformations and complex chemistry in nano-ligaments. A method based on the asymmetricity of synchrotron XRD peaks of NPC samples was also proposed to estimate the quantity of under-coordinated atoms on nano-ligaments, as ligament surface strain. Finally, CO reduction using electrochemistry mass spectrometry (EC-MS) demonstrated the promising performance of NPC compared to polycrystalline Cu. An optimal ligament surface strain value was also observed for the CO reduction on NPC, which provides more mechanistic insights into the complicated CO reduction process and an alternative strategy for Cu-based catalysts engineering. This work also shows how the application of synchrotron X-ray diffraction and EC-MS facilitates more efficient and accurate optimization of copper-based catalysts for electrochemical CO reduction.
Materials Science (cond-mat.mtrl-sci)
Thermoelectric processes of quantum normal-superconductor interfaces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
L. Arrachea, A. Braggio, P. Burset, E. J. H. Lee, A. Levy Yeyati, R. Sánchez
Superconducting interfaces have recently been demonstrated to contain a rich variety of effects that give rise to sizable thermoelectric responses and unexpected thermal properties, despite traditionally being considered poor thermoelectrics due to their intrinsic electron-hole symmetry. We review different mechanisms driving this response in hybrid normal-superconducting junctions, depending on the dimensionality of the mesoscopic interface. In addition to discussing heat to power conversion, cooling and heat transport, special emphasis is put on physical properties of hybrid devices that can be revealed by the thermoelectric effect.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
Review paper. 14 pages + references, 6 figures. Comments are welcome
Interaction Effects on the Electronic Floquet Spectra: Excitonic Effects
New Submission | Other Condensed Matter (cond-mat.other) | 2025-05-13 20:00 EDT
Teng Xiao, Tsan Huang, Changhua Bao, Zhiyuan Sun
Floquet engineering of electronic states by light is a central topic in modern experiments. However, the impact of many-body interactions on the single-electron properties remains unclear in this non-equilibrium situation. We propose that interaction effects could be reasonably understood by performing perturbative expansion in both the pump field and the electron-electron interaction when computing physical quantities. As an example, we apply this approach to semiconductors and show analytically that excitonic effects, i.e., effects of electron-hole interaction, lead to dramatic corrections to the single-electron Floquet spectra even when the excitons are only virtually excited by the pump light. We compute these effects in phosphorene and monolayer MoS$ _2$ for time- and angle-resolved photoemission spectroscopy (Tr-ARPES) and ultrafast optical experiments.
Other Condensed Matter (cond-mat.other), Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech), Optics (physics.optics), Quantum Physics (quant-ph)
Majorana edge modes in one-dimensional Kitaev chain with staggered $p$-wave superconducting pairing
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Xiao-Jue Zhang, Rong Lü, Qi-Bo Zeng
We introduce a new type of one-dimensional Kitaev chain with staggered $ p$ -wave superconducting pairing. We find three physical regimes in this model by tuning the $ p$ -wave pairing and the chemical potential of the system. In the topologically nontrivial phase, there are two Majorana zero modes localized at the opposite ends of the lattice, which are characterized and protected by nonzero topological invariants. More interestingly, we also find a regime where the system can hold four unprotected nonzero-energy edge modes in the trivial phase, which is analogous to a weak topological phase. The third regime is also trivial but holds no edge modes. The emergence of zero- and nonzero-energy edge modes in the system are analyzed by transforming the lattice model into a ladder consisting of Majorana fermions, where the competition between intra- and inter-leg couplings leads to the rich phase diagram. We further investigate the properties of edge modes under the influences of dissipation, which is represented by introducing a imaginary part in the chemical potential. Our work unveils the exotic properties induced by the staggered $ p$ -wave pairing and provides a new platform for further exploration of Majorana edge modes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn)
9 pages, 6 figures
DiffCrysGen: A Score-Based Diffusion Model for Design of Diverse Inorganic Crystalline Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Sourav Mal, Subhankar Mishra, Prasenjit Sen
Crystal structure generation is a foundational challenge in materials discovery, particularly in designing functional inorganic crystalline materials with desired properties. Most existing diffusion-based generative models for crystals rely on complex, hand-crafted priors and modular architectures to separately model atom types, atomic positions, and lattice parameters. These methods often require customized diffusion processes and conditional denoising, which can introduce additional model complexities and inconsistencies. Here we introduce DiffCrysGen, a fully data-driven, score-based diffusion model that jointly learns the distribution of all structural components in crystalline materials. With crystal structure representation as unified 2D matrices, DiffCrysGen bypasses the need for task-specific priors or decoupled modules, enabling end-to-end generation of atom types, fractional coordinates, and lattice parameters within a single framework. Our model learns crystallographic symmetry and chemical validity directly from large-scale datasets, allowing it to scale to complex materials discovery tasks. As a demonstration, we applied DiffCrysGen to the design of rare-earth-free magnetic materials with high saturation magnetization, showing its effectiveness in generating stable, diverse, and property-aligned candidates for sustainable magnet applications.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Unraveling the impact of competing interactions on non-equilibrium colloidal gelation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-13 20:00 EDT
Joeri Opdam, Michio Tateno, Hajime Tanaka
Competing interactions stabilize exotic mesoscopic structures, yet the microscopic mechanisms by which they influence non-equilibrium processes leading to disordered states remain largely unexplored, despite their critical role in self-assembly across a range of nanomaterials and biological systems. Here, we numerically investigate the structural evolution in charged colloidal model systems, where short-range attractions and long-range repulsions compete. We reveal that these two interaction scales drive sequential ordering within clusters, from tetrahedra motifs to linear aggregates with chiral order. This process disrupts early-stage percolated networks, resulting in reentrant behavior – a dynamic transition from disordered cluster to network to chiral rigid cluster. On the other hand, the cluster-elastic network boundary in the final state is governed by isostatic percolation, which slows structural rearrangements, preserves branching points, and sustains a long-lived network. The resulting structure consist of rigid Bernal spiral-like branches connected through flexible branching points lacking order. These insights advance our microscopic understanding of out-of-equilibrium ordering driven by competing interactions, particularly phenomena like temporally delayed frustration reflecting different length scales of competing interactions. The mechanisms identified here may play a crucial role in mesoscale self-organization across soft materials, from nanoparticle assemblies to biological gels and cytoskeletal networks. Understanding how competing interactions regulate structure and dynamics could guide the design of adaptive materials with tunable mechanical properties and offer new perspectives on biological processes such as cytoplasmic organization and cellular scaffolding.
Soft Condensed Matter (cond-mat.soft)
This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in ACS Nano, copyright 2025 American Chemical Society after peer review. To access the final edited and published work see this https URL
Optimized flux single-crystal growth of the quantum spin liquid candidate NdTa$7$O${19}$ and other rare-earth heptatantalates, ErTa$7$O${19}$ and GdTa$7$O${19}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Lia Šibav, Matic Lozinšek, Zvonko Jagličić, Tina Arh, Panchanana Khuntia, Andrej Zorko, Mirela Dragomir
Single crystals are essential for characterizing a wide range of magnetic states, including exotic ones such as quantum spin liquids. This study reports a flux method for growing single crystals of NdTa$ _7$ O$ _{19}$ , the first quantum spin liquid candidate on a triangular spin lattice with dominant Ising like spin correlations. Purple NdTa$ _7$ O$ _{19}$ single crystals with hexagonal morphology were successfully grown using a K$ _2$ Mo$ _3$ O$ _{10}$ -B$ _2$ O$ _3$ flux. With lateral sizes up to 3.5 mm and a thickness up to 2 mm, these are the largest dimensions reported to date. The chemical composition was confirmed by powder and single-crystal X-ray diffraction along with scanning electron microscopy with energy dispersive X-ray spectroscopy. Aiming for an accurate determination of the magnetic anisotropy and its effect on the magnetic properties, NdTa$ _7$ O$ _{19}$ crystals were additionally analyzed by magnetic susceptibility, revealing a substantial anisotropy without long-range magnetic ordering down to 2 K. Single crystals of two novel rare-earth heptatantalates, ErTa$ _7$ O$ _{19}$ and GdTa$ _7$ O$ _{19}$ , were also grown and their magnetic properties investigated. The magnetic anisotropy of ErTa$ _7$ O$ _{19}$ closely resembles that of isostructural NdTa$ _7$ O$ _{19}$ , indicating a possibility of a similar exotic magnetic ground state. In contrast, GdTa$ _7$ O$ _{19}$ shows paramagnetic behavior, consistent with previous results obtained for polycrystalline samples.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
24 pages, 11 figures, supplementary material
Low-energy effective Hamiltonian and end states of an inverted HgTe nanowire
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
The band inversion transition in a cylindrical HgTe nanowire is inducible via varying the nanowire radius. Here we derive the low-energy effective Hamiltonian describing the band structure of the HgTe nanowire close to the fundamental band gap. Because both the $ E_{1}$ and $ H_{1}$ subbands have quadratic dependence on $ k_{z}$ when the gap closes, we need to consider at least three subbands, i.e., the $ E_{1}$ , $ H_{1}$ , and $ H_{2}$ subbands, in building the effective Hamiltonian. The resulted effective Hamiltonian is block diagonal and each block is a $ 3\times3$ matrix. End states are found in the inverted regime when we solve the effective Hamiltonian with open boundary condition.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 4 figure
Beyond the Octupole Approximation in Non-Collinear Antiferromagnetic Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Freya Johnson, Jan Zemen, Geri Topore, Michele Shelly Conroy, Shanglong Ning, Jiahao Han, Shunsuke Fukami, Chiara Ciccarelli, Lesley F. Cohen
Noncollinear antiferromagnets offer much promise for antiferromagnetic spintronics and neuromorphic applications with a plethora of functional properties surpassing many competing magnetic systems. Films grown on mismatched substrates can relieve strain by the creation of slip-plane defects - and recently we have shown that these defects can manipulate global physical properties important for application. Here we demonstrate that post growth annealing results in near-defect-free, structurally robust films that allow the magnetic order thermal evolution to change as a function of film thickness. Strong spin-lattice coupling ensures that substrate clamping limits the ability of thinner films to transform as they are cooled to low temperature. However, beyond a certain thickness, films no longer suffer this constraint, revealing the extraordinary transformations that provide the pathway for spin to reach the lowest energy state. We show that this transition cannot be explained by the previously established mechanism of spin rotations in the (111) plane, and we calculate that rotations along the chirality-inverting [1-10] direction may be preferable under certain conditions. Our work suggests that chirality inverting rotations in these materials may have been previously overlooked in studies adopting the so-called octupole approximation of the net magnetic moment. This enriches the field of antiferromagnetic spintronics, raising the possibility of device designs with thickness engineered to exploit switching of chirality.
Materials Science (cond-mat.mtrl-sci)
14 pages, 5 figures
Topological characterization of Hopfions in finite-element micromagnetics
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Louis Gallard, Riccardo Hertel
Topological magnetic structures, such as Hopfions, are central to three-dimensional magnetism, but their characterization in complex geometries remains challenging. We introduce a robust finite-element method for calculating the Hopf index in micromagnetic simulations of three-dimensional nanostructures. By employing the Biot-Savart form for the vector potential, our approach ensures gauge-invariant results, even in multiply connected geometries like tori. A novel variance-based correction scheme significantly reduces numerical errors in highly inhomogeneous textures, achieving accurate Hopf index values with fast mesh-dependent convergence. We validate the method using an analytically defined Hopfion structure and demonstrate its ability to detect topological transitions through a simulation of a Hopfion’s field-induced destruction into a toron, marked by an abrupt change in the Hopf index. This method enables precise quantification of topological features in complex three-dimensional magnetic textures forming in finite-element micromagnetic simulations, offering a powerful tool for advancing topological magnetism studies in general geometries.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 8 figures. The following article has been submitted to Journal of Applied Physics. After it is published, it will be found at this https URL
Melting of Charge Density Waves in Low Dimensions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Jeremy M. Shen, Alex Stangel, Suk Hyun Sung, Ismail El Baggari, Kai Sun, Robert Hovden
Charge density waves (CDWs) are collective electronic states that can reshape and melt, even while confined within a rigid atomic crystal. In two dimensions, melting is predicted to be distinct, proceeding through partially ordered nematic and hexatic states that are neither liquid nor crystal. Here we measure and explain how continuous, hexatic melting of incommensurate CDWs occurs in low-dimensional materials. As a CDW is thermally excited, disorder emerges progressively$ \unicode{x2013}$ initially through smooth elastic deformations that modulate the local wavelength, and subsequently via the nucleation of topological defects. Experimentally, we track three hallmark signatures of CDW melting$ \unicode{x2013}$ azimuthal superlattice peak broadening, wavevector contraction, and integrated intensity decay.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 7 figures (includes supplemental)
Oxyfluoride glasses obtained through incorporation of CaF$_2$ into photovoltaic cover glass melts
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Rafaela Valcarenghi, Brenno Greatti Silva, Robson Ferrari Muniz, Vitor Santaella Zanuto, Anna Paulla Simon, Ricardo Schneider, Raquel Dosciatti Bini, Márcio Antônio Fiori, Maxence Vigier, Emmanuel Veron, Mathieu Allix, Marcelo Sandrini, Marcos Paulo Belançon
The glass industry has limited options to mitigate its environmental footprint, and the demand for cover glass to produce photovoltaic panels is increasing. Currently, the majority of this special type of glass is not being recycled, and in this work, we propose to reuse it as raw material to obtain oxyfluoride glasses. The incorporation of CaF$ _2$ and the increasing Na$ _2$ CO$ _3$ content resulted in a melting temperature of about 1200$ ^o$ C, significantly lower than in soda-lime glasses, which adds up to the environmental benefits of reusing end-of-life cover glass. The obtained samples show high transparency and thermal stability, allowing the cover glass to make up to 80% of its weight. XRF analysis was employed to determine the elemental composition of the samples, while XRD and Raman indicated that by adding CaF$ _2$ , the glass network was depolymerized. In situ XRD as a function of temperature showed the formation of a few crystalline phases in these oxyfluoride samples, evidencing that it can be explored as a matrix to obtain different glass-ceramics. The combination of the glass properties indicates that this method and the resulting material can contribute to reducing the environmental impact of the glass industry, by creating new glass or glass-ceramic materials that can be obtained at a reduced temperature compared to the soda-lime glass, while cover glass being the primary raw material could reduce the need to extract minerals from nature.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph)
21 pages, 7 figures
Gate modulation and interface engineering on Coulomb blockade in open superconducting islands
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Huading Song, Dong Pan, Runan Shang, Zhaoyu Wang, Ke He, Jianhua Zhao, Hao Zhang
Mesoscopic Coulomb blockade (MCB) is recognized as a phase-coherent variant of the conventional Coulomb blockade that arises in systems with open contacts. In open quantum dots, MCB is enhanced by a decrease in background conductance. This occurs because the reduction in coupling strength between the quantum dot and the outer reservoir renders the system more closed, thereby facilitating the emergence of conventional Coulomb blockade. In this work, we demonstrate that the MCB in open superconducting islands exhibits an different correlation with coupling strength compared to open quantum dots. Specifically, a decrease in background conductance may result in a weakening of the MCB. This observation indicates that the MCB in superconducting islands originates from the presence of superconducting-normal interfaces.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Explosive growth of bistability in a cavity magnonic system
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Meng-Xia Bi, Huawei Fan, Wenting Wu, Jing-Jing He, Ming-Liang Hu, Xiao-Hong Yan
We conduct a theoretical investigation into explosive growth of bistability in a cavity magnonic system incorporating magnetic nonlinearity. In this system, the coupling between the magnon and photon generates the cavity magnon polaritons. When driving the photon-like polariton mode, the bistability can undergo a sudden transition with the increase of the driving power, resulting in an explosive growth of the bistable region by several times. Conversely, driving the magnon-like polariton mode only gives rise to normal bistability. This depends on whether the minimum driving power required to generate the bistability is non-monotonic with respect to the driving frequency. In addition, despite driving only the photon-like polariton mode, the photon- and magnon-like polariton modes can show simultaneous explosive growth of the bistability in microwave transmission, owing to the light-matter interaction. Our research sheds light on the hidden side of the nonlinear cavity magnonic system and provides a potential application for cavity spintronic devices founded on this novel feature.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
11 pages, 8 figures
Phys. Rev. B 111, 184309 (2025)
Unveiling Phonon Contributions to Thermal Transport and the Failure of the Wiedemann-Franz Law in Ruthenium and Tungsten Thin Films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Md. Rafiqul Islam, Pravin Karna, Niraj Bhatt, Sandip Thakur, Helge Heinrich, Daniel M. Hirt, Saman Zare, Christopher Jezewski, Rinus T.P. Lee, Kandabara Tapily, John T.Gaskins, Colin D. Landon, Sean W. King, Ashutosh Giri, Patrick E. Hopkins
Thermal transport in nanoscale interconnects is dominated by intricate electron-phonon interactions and microstructural influences. As copper faces limitations at the nanoscale, tungsten and ruthenium have emerged as promising alternatives due to their substantial phonon contributions to thermal conductivity. Metals with stronger phonon-mediated thermal transport are particularly advantageous in nanoscale architectures, where phonons are less sensitive to size effects than electrons. Here, we show that phonons play a comparable role to electrons in the thermal transport of ruthenium and tungsten thin films, evidenced by deviations from the classical Wiedemann-Franz law. Elevated Lorenz numbers-1.9 and 2.7 times the Sommerfeld value for ruthenium and tungsten, respectively-indicate phonon contributions of 45% and 62% to total thermal conductivity. Comparisons of in-plane thermal conductivity from steady-state thermoreflectance and electron relaxation times from infrared ellipsometry reveal that phonon-mediated transport is insensitive to microstructural variations and scaling. Ultrafast infrared pump-probe measurements show that ruthenium exhibits a higher electron-phonon coupling factor than tungsten, consistent with the differing contributions of carriers to thermal transport. Molecular dynamics simulations and spectral energy density analysis confirm substantial phonon-driven thermal transport and mode-dependent phonon lifetimes. These results offer insights into phonon-driven thermal transport and provide design principles for selecting interconnects with enhanced thermal management.
Materials Science (cond-mat.mtrl-sci)
Hydrogen peroxide electrosynthesis: A comparative study employing Vulcan carbon modification by different MnO2 nanostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
João Paulo C Moura, Vanessa S Antonin, Aline B Trench, Mauro C Santos
The electrochemical performances of the {\alpha}-MnO2/Vulcan XC-72 and {\delta}-MnO2/Vulcan XC-72 nanostructures in hydrogen peroxide (H2O2) electrosynthesis were compared herein. Both materials were synthesized by a simple hydrothermal route. Their structures and morphologies were analyzed by SEM, HRTEM, XPS, Raman Scattering and XRD, and their ORR electrochemical properties and H2O2 electrosynthesis efficacies were investigated in alkaline NaOH solutions applying the rotating ring-disk electrode (RRDE) technique. Gas diffusion electrode (GDE) setups in acid media aiming at H2O2 formation were also performed. The 3% {\delta}-MnO2/C and 1% {\alpha}-MnO2/C electrocatalysts were more efficient and selective than pure Vulcan XC-72 through the ORR 2-electron pathway in the RRDE essays. Concerning H2O2 electrogeneration using GDE, the 1% {\alpha}-MnO2/C electrocatalyst displayed better activity, with peroxide accumulation of 402.6 mg/L at -1.9 V (vs Ag/AgCl) after 120 min, 48 % higher than pure Vulcan XC-72 GDE. These results can be ascribed to a synergistic effect between {\alpha}-MnO2 and Vulcan XC-72, as well as oxygen functional acid species improvement, increasing electrocatalytic surface hydrophilicity and enhancing H2O2 electrosynthesis.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Quantum Monte Carlo study of the bond- and site-diluted transverse-field Ising model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
C. Krämer, M. Hörmann, K.P. Schmidt
We study the transverse-field Ising model on a square lattice with bond- and site-dilution at zero temperature by stochastic series expansion quantum Monte Carlo simulations. Tuning the transverse field $ h$ and the dilution $ p$ , the quantum phase diagram of both models is explored. Both quantum phase diagrams show long-range order for small $ h$ and small $ p$ . The ordered phase of each is separated from the disordered (quantum) Griffiths phase by second-order phase transitions on two critical lines touching at a multi-critical point. Using Binder ratios we locate quantum critical points with high accuracy. The order-parameter critical exponent $ \beta$ and the average correlation-length exponent $ \nu_{\mathrm{av}}$ are determined along the critical lines and at the multi-critical points for the first time via finite-size scaling. We find three internally consistent sets of critical exponents and compare them with potentially connected universality classes. The quantum Griffiths phase in the vicinity of the phase transition lines is analyzed through the local susceptibility. Our results indicate that activated scaling occurs not only at the percolation transition, but also at the phase transition line for $ p$ smaller than the percolation threshold $ p_c$ .
Strongly Correlated Electrons (cond-mat.str-el)
10 pages, 6 figures
Fundamental Understanding of Exposure and Process Chemistry for Enhanced Lithography and Stability of Metal Oxide Resists
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Kevin M. Dorney, Ivan Pollentier, Fabian Holzmeier, Roberto Fallica, Ying-Lin Chen, Lorenzo Piatti, Dhirendra Singh, Laura Galleni, Michiel J. van Setten, Hyo Seon Suh, Danilo De Simone, Geoffrey Pourtois, Paul van der Heide, John Petersen
Metal oxide resists (MORs) have shown great promise for high resolution patterning in extreme ultraviolet (EUV) lithography, with potential for integration into high volume manufacturing. However, MORs have recently been shown to exhibit sensitivity to process conditions and environment, leading to critical dimension (CD) variation. While this variation can be reduced with proper process control, there is little knowledge on how these aspects affect the image formation mechanism. To bridge these knowledge gaps, we deploy a coordinated, fundamentals-focused approach to yield deep insights into MOR exposure and process chemistry. Our results on a model MOR, an n-butyl Sn-Oxo system, reveal how parameters such as exposure dose, post-exposure bake temperature, and atmospheric species influence the image formation mechanism. Our results, and the coordinated approach using correlative spectroscopies, provide a strong foundation for understanding the image formation mechanism in MOR materials with potential to link mechanistic aspects to CD variation.
Materials Science (cond-mat.mtrl-sci)
Proc. SPIE 13428, Advances in Patterning Materials and Processes XLII, 134281C (22 April 2025)
Design Principles for Realizable Discrete Surface Embeddings in Physical Systems
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-13 20:00 EDT
Kyungeun Kim, Christian D. Santangelo
The isometric embedding of surfaces in three-dimensional space is fundamental to various physical systems, from elastic sheets to programmable materials. While continuous surfaces typically admit unique solutions under suitable boundary conditions, their discrete counterparts-represented as networks of vertices connected by edges-can exhibit multiple distinct embeddings for identical edge lengths. We present a systematic approach to constructing discrete meshes that yield a controlled number of embeddings. By analyzing the relationship between mesh connectivity and embedding multiplicity through rigidity theory, we develop criteria for designing meshes that minimize solution multiplicity. We demonstrate computational methods based on local matrix operations and trilateration techniques, enabling practical implementation for meshes with approximately a thousand vertices. Our analysis provides both theoretical bounds on the number of possible embeddings based on Bézout’s theorem and practical guidelines for mesh construction in physical applications. Through numerical simulations, we show that this approach achieves comparable accuracy to traditional minimization methods while offering computational advantages through sequential computation. Importantly, we demonstrate that in cases where a unique smooth solution exists, local fluctuations in reconstructed shapes derived from the computational grid can serve as indicators of insufficient geometric constraints. This work bridges the gap between discrete and continuous embedding problems, providing insights for applications in 4D printing, mechanical meta-materials, and deployable structures.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Computational Physics (physics.comp-ph)
19 pages, 16 figures
Effective bands and band-like electron transport in amorphous solids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Matthew Jankousky, Dimitar Pashov, Ross E. Larsen, Vladimir Dobrosavljevic, Mark van Schilfgaarde, Vladan Stevanovic
The localization of electrons caused by atomic disorder is a well-known phenomenon. However, what circumstances allow electrons to remain delocalized and retain band-like characteristics even when the crystal structure is completely absent, as found in certain amorphous solids, is less well understood. To probe this phenomenon, we developed a fully first-principles description of the electronic structure and charge transport in amorphous solids by combining a novel representation of the amorphous state with the state-of-the-art many-body (QSGW) electronic structure theory. Using amorphous In2O3 as an example, we demonstrate the accuracy of our approach in reproducing the band-like nature of the conduction electrons as well as their disorder-limited mobility. Our approach reveals the physical origins responsible for the electron delocalization and the survival of the band dispersions despite the absence of long-range order.
Materials Science (cond-mat.mtrl-sci)
Interplay of localization and topology in disordered dimerized array of Rydberg atoms
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-13 20:00 EDT
Maksym Prodius, Adith Sai Aramthottil, Jakub Zakrzewski
Rydberg tweezer arrays provide a platform for realizing spin-1/2 Hamiltonians with long-range tunnelings decaying according to power-law with the distance. We numerically investigate the effects of positional disorder and dimerization on the properties of excited states in such a one-dimensional system. Our model allows for the continuous tuning of dimerization patterns and disorder strength. We identify different distinct ergodicity-breaking regimes within the parameter space constrained by our geometry. Notably, one of these regimes exhibits a unique feature in which non-trivial symmetry-protected topological (SPT) properties of the ground state extend to a noticeable fraction of states across the entire spectrum. This interplay between localization and SPT makes the system particularly interesting, as localization should help with stabilization of topological excitations, while SPT states contribute to an additional delocalization. Other regions of parameters correspond to more standard nonergodic dynamics resembling many-body localization.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
5pp+suppl, comments most welcome
Pyrite Bismuth Telluride Heterojunction for Hybrid Electromagnetic to Thermoelectric Energy Harvesting
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Karthik R, Yiwen Zheng, Caique Campos de Oliveira, Punathil Raman Sreeram, Pedro Alves da Silva Autreto, Aniruddh Vashisth, Chandra Sekhar Tiwary
The rapid proliferation of wireless networks and connected devices has led to pervasive electromagnetic (EM) energy dissipation into the environment, an underutilized resource for energy harvesting. Here, we demonstrate a pyrite (FeS$ _2$ )-bismuth telluride (Bi$ _2$ Te$ _3$ ) heterojunction that enables hybrid electromagnetic-to-thermoelectric energy conversion. Fabricated via a simple cold-press compaction of powders, the heterojunction forms a Schottky interface at FeS$ _2$ , facilitating efficient RF absorption and localized heating. This heat is harvested by Bi$ _2$ Te$ _3$ through thermoelectric conversion. Under 35MHz RF irradiation at 1W input power, the device achieved a local temperature rise of 46$ ^\circ$ C and a thermal gradient of 5.5K across the Bi$ _2$ Te$ _3$ , resulting in a peak power density of approximately 13~mW/cm$ ^2$ . Molecular dynamics (MD) simulations and density functional theory (DFT) calculations further elucidate the heat transport behavior and interfacial thermoelectric performance. This work introduces a new class of heterostructures for RF-responsive energy harvesting, offering a scalable route toward self-powered IoT and wireless sensing systems.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
29 pages, 8 Figures
Spatio-temporal spin transport from first principles
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
Mayada Fadel, Joshua Quinton, Mani Chandra, Mayank Gupta, Yuan Ping, Ravishankar Sundararaman
We introduce a computational framework for first-principles density matrix transport within the Wigner function formalism to predict transport of quantum-mechanical degrees of freedom such as spin over long time and length scales. This framework facilitates simulation of spin dynamics and transport from first principles, while accounting for electron-phonon scattering at device length scales. We demonstrate this framework to elucidate the impact of various spin-orbit field profiles, such as Rashba and persistent spin helix, on coherent spin transport in several materials. Using graphene under an electric field as an example to illustrate the impact of electron-phonon scattering on incoherent transport, we show how the transport changes with the strength of scattering. We identify three distinct regimes of incoherent spin transport corresponding to the free induction decay, Dyakonov-Perel and Elliott-Yafet regimes of spin relaxation. In particular, we show that the spin diffusion length is insensitive to the strength of scattering within the Dyakonov-Perel regime.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
5 pages, 3 figures
Mapping of Microstructure Transitions during Rapid Alloy Solidification Using Bayesian-Guided Phase-Field Simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
José Mancias, Brent Vela, Juan Flórez-Coronel, Rouhollah Tavakoli, Douglas Allaire, Raymundo Arróyave, Damien Tourret
This study addresses microstructure selection mechanisms in rapid solidification, specifically targeting the transition from cellular/dendritic to planar interface morphologies under conditions relevant to additive manufacturing. We use a phase-field model that quantitatively captures solute trapping, kinetic undercooling, and morphological instabilities across a broad range of growth velocities ($ V$ ) and thermal gradients ($ G$ ), and apply it to a binary Fe-Cr alloy, as a surrogate for 316L stainless steel. By combining high-fidelity phase-field simulations with a Gaussian Process-based Bayesian active learning approach, we efficiently map the microstructure transitions in the multi-dimensional space of composition, growth velocity, and temperature gradient. We compare our PF results to classical theories for rapid solidification. The classical KGT model yields an accurate prediction of the value of $ G$ above which the interface is planar for any growth velocity. Microstructures transition from dendrites to cells as the temperature gradient increases close to this value of $ G$ . We also identify the occurrence of unstable “intermediate” microstructures at the border between dendritic and planar at low $ G$ , in the absence of banding instability in this Fe-Cr alloy. Our results highlight the capabilities of Bayesian-guided PF approaches in exploring complex microstructural transitions in multidimensional parameters spaces, thereby providing a robust computational tool for designing process parameters to achieve targeted microstructures and properties in rapidly solidified metallic alloys.
Materials Science (cond-mat.mtrl-sci)
Non-linear flow of two-dimensional viscous electron fluid in moderate magnetic fields
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
In two-dimensional (2D) electron systems, the inter-particle interaction can lead to the formation of a viscous electron fluid and realization of the hydrodynamic regime of electron transport. Here a nonlinear model of the electron hydrodynamic transport is constructed based on the accounting of pair correlations in the electron dynamics. When describing these systems within the framework of classical kinetics, such correlations represent subsequent ``extended’’ collisions of the same electrons temporarily joined into pairs. We study their influence on stationary magnetotransport for large-amplitude fluid flows in long samples. Current profiles in the nonlinear regime and the corresponding differential magnetoresistance are calculated. Pair correlations lead to a characteristic nonmonotonic dependence of the differential resistance on magnetic field. We compare our results with experimental data on magnetoresistance of 2D electrons in high-purity GaAs quantum wells; our model can be responsible for a part of the observed features of the differential magnetoresistance.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 2 figures
Unraveling Mn intercalation and diffusion in NbSe$_2$ bilayers through DFTB simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Bruno Ipaves, Raphael B. de Oliveira, Guilherme da Silva Lopes Fabris, Matthias Batzill, Douglas S. Galvão
Understanding transition metal atoms’ intercalation and diffusion behavior in two-dimensional (2D) materials is essential for advancing their potential in spintronics and other emerging technologies. In this study, we used density functional tight binding (DFTB) simulations to investigate the atomic-scale mechanisms of manganese (Mn) intercalation into NbSe$ _2$ bilayers. Our results show that Mn prefers intercalated and embedded positions rather than surface adsorption, as cohesive energy calculations indicate enhanced stability in these configurations. Nudged elastic band (NEB) calculations revealed an energy barrier of 0.68 eV for the migration of Mn into the interlayer, comparable to other substrates, suggesting accessible diffusion pathways. Molecular dynamics (MD) simulations further demonstrated an intercalation concentration-dependent behavior. Mn atoms initially adsorb on the surface and gradually diffuse inward, resulting in an effective intercalation at higher Mn densities before clustering effects emerge. These results provide helpful insights into the diffusion pathways and stability of Mn atoms within NbSe$ _2$ bilayers, consistent with experimental observations and offering a deeper understanding of heteroatom intercalation mechanisms in transition metal dichalcogenides.
Materials Science (cond-mat.mtrl-sci)
Unconventional Fractional Phases in Multi-Band Vortexable Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Siddhartha Sarkar, Xiaohan Wan, Ang-Kun Wu, Shi-Zeng Lin, Kai Sun
In this Letter, we study topological flat bands with distinct features that deviate from conventional Landau level behavior. We show that even in the ideal quantum geometry limit, moire flat band systems can exhibit physical phenomena fundamentally different from Landau levels without lattices. In particular, we find new fractional quantum Hall states emerging from multi-band vortexable systems, where multiple exactly flat bands appear at the Fermi energy. While the set of bands as a whole exhibits ideal quantum geometry, individual bands separately lose vortexability, and thus making them very different from a stack of Landau levels. At certain filling fractions, we find fractional states whose Hall conductivity deviates from the filling factor. Through careful numerical and analytical studies, we rule out all known mechanisms–such as fractional quantum Hall crystals or separate filling of trivial and topological bands–as possible explanations. Leveraging the exact solvability of vortexable systems, we use analytic Bloch wavefunctions to uncover the origin of these new fractional states, which arises from the commensurability between the moire unit cell and the magnetic unit cell of an emergent effective magnetic field.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Emerging (2+1)D electrodynamics and topological instanton in pseudo-Hermitian two-level systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-13 20:00 EDT
We reveal a hidden electrodynamical structure emerging from a general $ 2\times2$ pseudo-Hermitian system that exhibits real spectra. Even when the Hamiltonian does not explicitly depend on time, the Berry curvature can be mapped onto a $ 2+1$ dimensional electromagnetic field arising from an artificial spacetime instanton, in sharp contrast to the Hermitian systems where the Berry curvature is equivalent to the static magnetic field of a magnetic monopole in three spatial dimensions. The instanton appearing as a spacetime singularity carries a topological charge that quantizes the jump of magnetic flux of the Berry curvature at the time origin. Our findings are demonstrated in a simple example related to antiferromagnetic magnons.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
Classical symmetry enriched topological orders and distinct monopole charges for dipole-octupole spin ices
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-13 20:00 EDT
Distinct symmetry enriched topological orders often do not have classical distinctions. Motivated by the recent process on the pyrochlore spin ice materials based on the dipole-octupole doublets, we argue that dipolar spin liquid and octupolar spin liquid can be well differentiated through the magnetic charges of the magnetic monopoles in the classical spin ice regime. It is observed and predicted that, the long-range dipole-dipole interaction renders the magnetic monopole of the dipolar spin ice a finite magnetic charge via the dumbbell picture even in the classical regime. For the octupolar spin ice, however, a zero magnetic charge is expected from this mechanism in the classical regime. We expect this smoking-gun observation to resolve the debate on the nature of Ce$ _2$ Sn$ _2$ O$ _7$ , and more broadly, this work may inspire further experiments and thoughts on the Ce-pyrochlore spin liquids, Nd-pyrochlore antiferromagnets, Er-based spinels, and the distinct properties of the emergent quasiparticles in various symmetry enriched topological phases.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
5 pages, 1 figure, 2 tables
Two-step phase transitions in Fe(Se,Te)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-13 20:00 EDT
D.A. Chareev, A.A. Gippius, Y.A. Ovchenkov, D.E. Presnov, I.G. Puzanova, A.V. Tkachev, O.S. Volkova, S.V. Zhurenko, A.N. Vasiliev
In the studied crystals of FeSe0.7 Te0.3 , a structural phase transition occurs in two stages. At higher temperatures, the electronic subsystem undergoes a reconstruction, leading to a significant increase in elastoresistance. 77 Se NMR data show an abrupt change in the relaxation rate during this transition. The final transition occurs at a temperature several degrees below and is also accompanied by anomalies in the electronic properties. Thus, in the Fe(Se,Te) series, similarly to the behavior of pure FeSe under pressure, the type of transition changes and intermediate state appear before the structural transition is suppressed. This similarity between the corresponding phase diagrams is explained by the same deformation of the iron coordination environment in Fe(Se,Te) compounds and in FeSe under pressure. Our findings provide new and significant information on the phase diagram of Fe(Se,Te) compounds and in particular suggest the possible existence of a triple point near the quantum critical point.
Superconductivity (cond-mat.supr-con)
PtyRAD: A High-performance and Flexible Ptychographic Reconstruction Framework with Automatic Differentiation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-13 20:00 EDT
Chia-Hao Lee, Steven E. Zeltmann, Dasol Yoon, Desheng Ma, David A. Muller
Electron ptychography has recently achieved unprecedented resolution, offering valuable insights across diverse material systems, including in three dimensions. However, high-quality ptychographic reconstruction is computationally expensive and time consuming, requiring a significant amount of manually tuning even for experts. Additionally, essential tools for ptychographic analysis are often scattered across multiple software packages, with some advanced features available only in costly commercial software like MATLAB. To address these challenges, we introduce PtyRAD, an open-source software framework offers a comprehensive, flexible, and computationally efficient solution for electron ptychography. PtyRAD provides seamless optimization of multiple parameters–such as sample thickness, local tilts, probe positions, and mixed probe and object modes–using gradient-based methods with automatic differentiation (AD). By utilizing PyTorch’s highly optimized tensor operations, PtyRAD achieves up to a 17x speedup in reconstruction time compared to existing packages without compromising image quality. In addition, we propose a real-space depth regularization, which avoids wrap-around artifacts and can be useful for twisted two-dimensional (2D) material datasets and vertical heterostructures. Moreover, PtyRAD integrates a Bayesian optimization workflow that streamlines hyperparameter selection. We hope the open-source nature of PtyRAD will foster reproducibility and community-driven development for future advances in ptychographic imaging.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
16 pages, 6 figures