CMP Journal 2025-06-12
Statistics
Nature: 1
Nature Materials: 2
Physical Review Letters: 12
Physical Review X: 1
arXiv: 73
Nature
An instantaneous voice-synthesis neuroprosthesis
Original Paper | Brain-machine interface | 2025-06-11 20:00 EDT
Maitreyee Wairagkar, Nicholas S. Card, Tyler Singer-Clark, Xianda Hou, Carrina Iacobacci, Lee M. Miller, Leigh R. Hochberg, David M. Brandman, Sergey D. Stavisky
Brain-computer interfaces (BCIs) have the potential to restore communication for people who have lost the ability to speak owing to a neurological disease or injury. BCIs have been used to translate the neural correlates of attempted speech into text1,2,3. However, text communication fails to capture the nuances of human speech, such as prosody and immediately hearing one’s own voice. Here we demonstrate a brain-to-voice neuroprosthesis that instantaneously synthesizes voice with closed-loop audio feedback by decoding neural activity from 256 microelectrodes implanted into the ventral precentral gyrus of a man with amyotrophic lateral sclerosis and severe dysarthria. We overcame the challenge of lacking ground-truth speech for training the neural decoder and were able to accurately synthesize his voice. Along with phonemic content, we were also able to decode paralinguistic features from intracortical activity, enabling the participant to modulate his BCI-synthesized voice in real time to change intonation and sing short melodies. These results demonstrate the feasibility of enabling people with paralysis to speak intelligibly and expressively through a BCI.
Brain-machine interface, Neural decoding
Nature Materials
Configurable antiferromagnetic domains and lateral exchange bias in atomically thin CrPS4
Original Paper | Magnetic devices | 2025-06-11 20:00 EDT
Yu-Xuan Wang, Thomas K. M. Graham, Ricardo Rama-Eiroa, Md Ariful Islam, Mohammad H. Badarneh, Rafael Nunes Gontijo, Ganesh Prasad Tiwari, Tibendra Adhikari, Xin-Yue Zhang, Kenji Watanabe, Takashi Taniguchi, Claire Besson, Elton J. G. Santos, Zhong Lin, Brian B. Zhou
Interfacial exchange coupling between antiferromagnets (AFMs) and ferromagnets (FMs) crucially makes it possible to shift the FM hysteresis, known as exchange bias, and to switch AFM states. Two-dimensional magnets unlock opportunities to combine AFM and FM materials; however, the buried AFM-FM interfaces obtained by stacking remains challenging to understand. Here we demonstrate interfacial control via intralayer exchange coupling in the layered AFM CrPS4, where connected even and odd layers realize pristine lateral interfaces between AFM-like and FM-like regions. We distinguish antiphase even-layer states by scanning nitrogen-vacancy centre magnetometry due to a weak surface magnetization. This surface magnetization enables control over the even-layer state, with different regions switching at distinct fields due to their own lateral couplings. We toggle three AFM domains adjacent to a FM-like region and demonstrate a tunable multilevel exchange bias. Our nanoscale visualization unveils the microscopic origins of exchange bias and advances single two-dimensional crystals for hybrid AFM-FM technologies.
Magnetic devices, Magnetic properties and materials, Quantum metrology, Spintronics, Two-dimensional materials
Hybrid hydrogel-extracellular matrix scaffolds identify biochemical and mechanical signatures of cardiac ageing
Original Paper | Bioinspired materials | 2025-06-11 20:00 EDT
Avery Rui Sun, Md Faris H. Ramli, Xingyu Shen, Karthikbabu Kannivadi Ramakanth, Dixiao Chen, Yang Hu, Prasanna Vidyasekar, Roger S. Foo, Yuchen Long, Jin Zhu, Matthew Ackers-Johnson, Jennifer L. Young
Extracellular matrix remodelling of cardiac tissue is a key contributor to age-related cardiovascular disease and dysfunction. Such remodelling is multifaceted including changes to the biochemical composition, architecture and mechanics, clouding our understanding of how and which extracellular matrix properties contribute to a dysfunctional state. Here we describe a decellularized extracellular matrix-synthetic hydrogel hybrid scaffold that independently confers two distinct matrix properties–ligand presentation and stiffness–to cultured cells in vitro, allowing for the identification of their specific roles in cardiac ageing. The hybrid scaffold maintains native matrix composition and organization of young or aged murine cardiac tissue, whereas its mechanical properties can be independently tuned to mimic young or aged tissue stiffness. Seeding these scaffolds with murine primary cardiac fibroblasts, we identify distinct age- and matrix-dependent mechanisms of cardiac fibroblast activation, matrix remodelling and senescence. Importantly, we show that the ligand presentation of a young extracellular matrix can outweigh the profibrotic stiffness cues typically present in an aged extracellular matrix in maintaining or driving cardiac fibroblast quiescence. Ultimately, these tunable scaffolds can enable the discovery of specific extracellular targets to prevent ageing dysfunction and promote rejuvenation.
Bioinspired materials, Biomaterials - cells, Biomedical engineering, Extracellular matrix, Tissues
Physical Review Letters
Enhancing Quantum Metrology by Quantum Resonance Dynamics
Research article | Quantum chaos | 2025-06-11 06:00 EDT
Zhixing Zou, Jiangbin Gong, and Weitao Chen
Quantum effects in metrology can in principle enhance measurement precision from the so-called standard quantum limit to the Heisenberg limit. Further advancements in quantum metrology largely rely on innovative metrology protocols that can avoid a number of known obstacles, including the challenge of preparing entangled states with sufficient fidelity, the readout noise in measuring highly entangled states, and no-go theorems for quantum metrology under noisy environments. In this Letter, exploiting some peculiar but experimentally feasible dynamical features of a collection of spins with all-to-all time-periodic interactions, we propose a metrology protocol that can circumvent all three mentioned obstacles and yet still make good use of time as a resource for metrology. Specifically, by mapping the dynamics of such a periodically driven spin system to that of a paradigm of quantum chaos but tuned to some high-order quantum resonance, it is shown that a simple SU(2) coherent state can, after evolving to highly entangled states in the ensuing dynamics, be dynamically brought back to the same initial coherent state. The associated quantum Fisher information is found to exhibit quadratic scaling with both the number of spins and the duration of the metrology protocol. The achieved Heisenberg scaling can also largely survive in the presence of Markovian noise. Representing a previously unknown strategy for quantum metrology, the protocol proposed here can be tested on available experimental platforms.
Phys. Rev. Lett. 134, 230802 (2025)
Quantum chaos, Quantum control, Quantum metrology
Measurement of In-Medium Jet Modification Using Direct $\mathrm{Photon}+\text{Jet}$ and ${\pi }^{0}+\text{Jet}$ Correlations in $p+p$ and Central $\mathrm{Au}+\mathrm{Au}$ Collisions at $\sqrt{ {s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$
Research article | Hard scattering | 2025-06-11 06:00 EDT
B. E. Aboona et al. (STAR Collaboration)
The STAR Collaboration presents measurements of the semi-inclusive distribution of charged-particle jets recoiling from energetic direct-photon (${\gamma }{\mathrm{dir}}$) and neutral-pion (${\pi }^{0}$) triggers in $p+p$ and central $\mathrm{Au}+\mathrm{Au}$ collisions at $\sqrt{ {s}{NN}}=200\text{ }\text{ }\mathrm{GeV}$ over a broad kinematic range, for jet resolution parameters $R=0.2$ and 0.5. Medium-induced jet yield suppression is observed to be larger for $R=0.2$ than for 0.5, reflecting the angular range of jet energy redistribution due to quenching. The predictions of model calculations incorporating jet quenching are not fully consistent with the observations. These results provide new insight into the physical origins of jet quenching.
Phys. Rev. Lett. 134, 232301 (2025)
Hard scattering, Jet quenching, Quark-gluon plasma
Probing the Shell Effects on Fission: The New Superheavy Nucleus $^{257}\mathrm{Sg}$
Research article | Fission | 2025-06-11 06:00 EDT
P. Mosat, J. Khuyagbaatar, J. Ballof, R. A. Cantemir, D. Dietzel, Ch. E. Düllmann, K. Hermainski, F. P. Heßberger, E. Jäger, B. Kindler, J. Krier, N. Kurz, B. Lommel, S. Löchner, M. Maiti, T. K. Sato, B. Schausten, J. Uusitalo, P. Wieczorek, and A. Yakushev
A new isotope 257Sg, decaying by both spontaneous fission and α-particle emission, was discovered at GSI’s gas-filled recoil separator TASCA.
Phys. Rev. Lett. 134, 232501 (2025)
Fission, Isomer decays, Nuclear structure & decays, A ≥ 220
Bose-Einstein Condensates of Microwave-Shielded Polar Molecules
Research article | Cold and ultracold molecules | 2025-06-11 06:00 EDT
Wei-Jian Jin, Fulin Deng, Su Yi, and Tao Shi
We investigate the ground-state phases of ultracold gases composed of bosonic microwave-shielded polar molecules (MSPMs). Using a translational symmetry-breaking variational ansatz with Jastrow correlations, we characterize the many-body correlations arising from the large shielding core of the two-body potential in a dense gas. We show that the molecular gases are always stabilized by the shielding potential and support a self-bound gas phase and an expanding gas phase. Furthermore, we find that, analogous to liquid $^{4}\mathrm{He}$, the condensate fraction is significantly reduced when the size of the shielding core of the two-body potential becomes comparable to the intermolecular distance. For experimental detection, we also identify a bimodal feature in the momentum distribution. Our work invalidates the application of the Gross-Pitaevskii equation to molecular gases and establishes a universal framework to reveal the many-body correlations in dense molecular gases.
Phys. Rev. Lett. 134, 233003 (2025)
Cold and ultracold molecules, Dipolar gases, Scattering of atoms, molecules, clusters & ions, Bose-Einstein condensates, Molecular condensates, Ultracold gases, Nonperturbative methods
Conditional Entanglement Amplification via Non-Hermitian Superradiant Dynamics
Research article | Cavity quantum electrodynamics | 2025-06-11 06:00 EDT
Christoph Hotter, Arkadiusz Kosior, Helmut Ritsch, and Karol Gietka
Because of the inherently probabilistic nature of quantum mechanics, each experimental realization of a dynamical quantum system can produce distinct measurement outcomes, particularly when coupled to a dissipative environment. Although quantum trajectories that lead to exotic, highly entangled states are possible in principle, their observation is typically hindered by extremely low probabilities. In this Letter, we present a method to significantly enhance the probability of generating highly entangled states in an ensemble of atoms undergoing collective superradiant decay on timescales much shorter than the individual atomic spontaneous emission rate. By analyzing an effective non-Hermitian Hamiltonian governing the dynamics between photon emission events, we identify the conditions necessary for these rare no-click trajectories to occur with higher likelihood. Crucially, our method relies on initializing the system in a nonclassical state, whose entanglement is amplified via the non-Hermitian superradiant dynamics. This approach provides a new route to creating highly entangled macroscopic states such as atomic Schr"odinger cat states, paving the way for advancements in quantum metrology and other quantum technologies.
Phys. Rev. Lett. 134, 233601 (2025)
Cavity quantum electrodynamics, Light-matter interaction, Open quantum systems, Quantum entanglement, Superradiance & subradiance
Chiral Dissociation of Bound Photon Pairs for a Non-Hermitian Skin Effect
Research article | Collective effects in quantum optics | 2025-06-11 06:00 EDT
Jiaming Shi and Alexander N. Poddubny
We theoretically study the bound states of interacting photons propagating in a waveguide chirally coupled to an array of atoms. We demonstrate that the bound photon pairs can concentrate at the edge of the array and link this to the non-Hermitian skin effect. Unlike tight-binding non-Hermitian setups, the bound states in the waveguide-coupled array exhibit infinite radiative lifetimes when the array has an infinite size. However, in a finite array, non-Hermiticity and localization of bound pairs emerge due to their chiral dissociation into scattering states. Counterintuitively, when the photons are preferentially emitted to the right, the bound pairs are localized at the left edge of the array and vice versa.
Phys. Rev. Lett. 134, 233602 (2025)
Collective effects in quantum optics, Quantum optics with artificial atoms, Topological effects in photonic systems, Non-Hermitian systems
Hierarchical Verification of Non-Gaussian Coherence in Bosonic Quantum States
Research article | Quantum coherence & coherence measures | 2025-06-11 06:00 EDT
Beate E. Asenbeck, Lukáš Lachman, Ambroise Boyer, Priyanka Giri, Alban Urvoy, Radim Filip, and Julien Laurat
Non-Gaussianity, a distinctive characteristic of bosonic quantum states, is pivotal in advancing quantum networks, fault-tolerant quantum computing, and high-precision metrology. Verifying the quantum nature of a state, particularly its non-Gaussian features, is essential for ensuring the reliability and performance of these technologies. However, the specific properties required for each application demand tailored validation thresholds. Here, we introduce a hierarchical framework comprising absolute, relative, and qubit-specific thresholds to assess the non-Gaussianity of local coherences. We illustrate this framework using heralded optical non-Gaussian states with the highest purities available in optical platforms. This comprehensive framework presents the first detailed evaluation of number state coherences and can be extended to a wide range of bosonic states.
Phys. Rev. Lett. 134, 233604 (2025)
Quantum coherence & coherence measures, Quantum optics, Quantum protocols, Quantum state engineering
Causality and Instability in Wave Propagation in Random Time-Varying Media
Research article | Classical optics | 2025-06-11 06:00 EDT
R. Pierrat, J. Rocha, and R. Carminati
We develop a theoretical model to investigate wave propagation in media with random time-varying properties, where temporal fluctuations lead to complex scattering dynamics. Focusing on the ensemble-averaged field, we derive an exact expression for the average Green’s function in the presence of finite temporal disorder, and extend the analysis to the thermodynamic limit. In contrast to spatial disorder, causality prevents recurrent scattering, allowing us to achieve a nonperturbative solution. We introduce an effective medium description providing a simple analysis of the propagation regimes. Our findings offer new insights into wave dynamics in temporally disordered media, with potential applications in time-varying metamaterials, dynamic sensing, and imaging in turbulent or chaotic environments.
Phys. Rev. Lett. 134, 233801 (2025)
Classical optics, Disordered systems, Transfer matrix method
Physics of Edge-Core Coupling by Inward Turbulence Propagation
Research article | Drift waves | 2025-06-11 06:00 EDT
Mingyun Cao and P. H. Diamond
A model that includes propagating voids predicts the extent of plasma turbulence in a tokamak.
Phys. Rev. Lett. 134, 235101 (2025)
Drift waves, Magnetic confinement fusion, Plasma turbulence, Magnetically confined plasmas, Tokamaks
Non-Fermi Liquids from Subsystem Symmetry Breaking in van der Waals Multilayers
Research article | Excitons | 2025-06-11 06:00 EDT
Archisman Panigrahi and Ajesh Kumar
We investigate the spontaneous breaking of subsystem symmetry in a stack of two-dimensional Fermi liquid metals, each maintaining a subsystem number conservation symmetry, driven by interlayer exciton condensation. The resulting Goldstone modes in this broken symmetry phase couple to the quasiparticle current perpendicular to the layers. This coupling, which remains nonzero for small momentum transfers, leads to the emergence of a three-dimensional anisotropic marginal Fermi liquid state when the number of layers is sufficiently large. We propose a possible experimental realization of this phenomenon in two-dimensional multilayer van der Waals heterostructures. Using self-consistent mean-field calculations, we characterize the subsystem symmetry-broken metallic state and examine the effects of fluctuations on its physical properties within the random phase approximation. We find that these fluctuations produce additional logarithmic enhancements to the specific heat at low temperature, specifically $C\sim T[\mathrm{log}(1/T){]}^{2}$.
Phys. Rev. Lett. 134, 236502 (2025)
Excitons, Exotic phases of matter, Specific heat, Layered crystals, Non-Fermi-liquid theory
Magnetic Switching of Phonon Angular Momentum in a Ferrimagnetic Insulator
Research article | Ferrimagnetism | 2025-06-11 06:00 EDT
Fangliang Wu, Jing Zhou, Song Bao, Liangyue Li, Jinsheng Wen, Yuan Wan, and Qi Zhang
Circularly polarized phonons offer a new route for mediating angular momentum in solids. However, controlling phonon angular momentum without altering the material’s structure or composition remains challenging. Here, we demonstrate the nonvolatile switching of angular momentum-carrying phonons by leveraging intrinsic ferrimagnetism in an insulator. We find a pair of chiral phonons with giant energy splitting, reaching 20% of the phonon frequency due to spontaneously broken time-reversal symmetry. With a moderate magnetic field, the phonon angular momentum of the two chiral phonon branches can be switched along with the magnetization. Notably, near the critical temperature, the effective phonon magnetic moment is enhanced, reaching 2.62 Bohr magneton, exceeding the moment of a magnon. A microscopic model based on phonon-magnon coupling accounts for the observations. Furthermore, we identify two types of phononic domains with opposite phonon Zeeman splitting and propose the existence of topologically protected phononic edge modes at domain boundaries. These results demonstrate effective manipulation of chiral phonons with magnetism, and pave the way for engineering chiral phononic domains on the micrometer scale.
Phys. Rev. Lett. 134, 236701 (2025)
Ferrimagnetism, Magneto-optics, Phonons, Spin-phonon coupling
Ballast Charges for Semiconductor Spin Qubits
Research article | Charge | 2025-06-11 06:00 EDT
Yujun Choi, John M. Nichol, and Edwin Barnes
Semiconductor spin qubits are an attractive platform for quantum computing, but their performance is degraded primarily by fluctuating electromagnetic environments. We introduce the concept of ballast charges, which are induced charges on the surface of an additional screening layer situated below the qubits. The counteractive behavior of these charges can significantly reduce the power spectral density associated with fluctuations from two-level systems that contribute to charge noise. Our simulations show that the dephasing time of a single-spin qubit in a Si/SiGe device increases by a factor of 4 to 6 on average when using this method. We also discuss the physical implementation and potential challenges of this approach.
Phys. Rev. Lett. 134, 237002 (2025)
Charge, Electrostatic interactions, Noise, Quantum coherence & coherence measures, Quantum information with solid state qubits, Two-dimensional electron system
Physical Review X
How Much Entanglement Is Needed for Topological Codes and Mixed States with Anomalous Symmetry?
Research article | Anyons | 2025-06-11 06:00 EDT
Zhi Li, Dongjin Lee, and Beni Yoshida
Topological phases require quantum entanglement that scales extensively with system size. This long-range entanglement is essential for supporting emergent particles, anomalous symmetries, and robust quantum error correction.
Phys. Rev. X 15, 021090 (2025)
Anyons, Entanglement measures, Fermions, Quantum error correction, Topological phases of matter
arXiv
GPa Pressure Imaging Using Nanodiamond Quantum Sensors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Ryotaro Suda, Kenshin Uriu, Kouki Yamamoto, Misaki Sasaki, Kento Sasaki, Mari Einaga, Katsuya Shimizu, Kensuke Kobayashi
We demonstrate wide-field optical microscopy of the pressure distribution at approximately 20 GPa in a diamond anvil cell (DAC), using nitrogen-vacancy (NV) centers in nanodiamonds (NDs) as quantum sensors. Pressure and non-hydrostaticity maps are obtained by fitting optically detected magnetic resonance (ODMR) spectra with models incorporating hydrostatic and uniaxial stress conditions. Two methods for introducing NDs with a pressure-transmitting medium are compared, revealing that the embedding approach affects the degree of non-hydrostaticity. This ND-based technique offers a powerful imaging platform for probing pressure-induced phenomena and is extendable to other physical quantities such as magnetic fields.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
10 pages, 8 figures, submitted to Journal of the Physical Society of Japan
“Symmetry-from-Anomaly” in Condensed Matter related Constructions
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
The noninvertible axial symmetry constructed from the ABJ-anomaly has attracted enormous interest. We discuss the mechanism of “symmetry-from-anomaly” in condensed matter-related models in both 1d and 3d spaces (which correspond to (1+1)d and (3+1)d space-time). Within the models discussed here, we establish the connection between field theory quantities such as different versions of the axial charge, and quantities with simple physical meanings in our systems. In our models and likely a class of related constructions, the existence of a topological order is necessary for the purpose of properly defining the axial symmetry. But the proper axial symmetry we define, though requires a topological order, is different from the noninvertible axial symmetry discussed in recent proposals.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
10 pages, 3 figures
Digital Quantum Simulation of the Kitaev Quantum Spin Liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
The ground state of the Kitaev quantum spin liquid on a honeycomb lattice is an intriguing many-body state characterized by its topological order and massive entanglement. One of the significant issues is to prepare and manipulate the ground state as well as excited states in a quantum simulator. Here, we provide a protocol to manipulate the Kitaev quantum spin liquid via digital quantum simulation. A series of unitary gates for the protocol is explicitly constructed, showing its circuit depth is an order of $ \mathcal{O}(N)$ with the number of qubits, N. We demonstrate the efficiency of our protocol on the IBM Heron r2 processor for N = 8 and 12. We further validate our theoretical framework through numerical simulations, confirming high-fidelity quantum state control for system sizes up to N = 450, and discuss the possible implications of these results.
Strongly Correlated Electrons (cond-mat.str-el)
20 pages, 12 figures
(2+1)d Lattice Models and Tensor Networks for Gapped Phases with Categorical Symmetry
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Kansei Inamura, Sheng-Jie Huang, Apoorv Tiwari, Sakura Schafer-Nameki
Gapped phases in 2+1 dimensional quantum field theories with fusion 2-categorical symmetries were recently classified and characterized using the Symmetry Topological Field Theory (SymTFT) approach arXiv:2408.05266, arXiv:2502.20440. In this paper, we provide a systematic lattice model construction for all such gapped phases. Specifically, we consider ``All boson type” fusion 2-category symmetries, all of which are obtainable from 0-form symmetry groups $ G$ (possibly with an ‘t Hooft anomaly) via generalized gauging–that is, by stacking with an $ H$ -symmetric TFT and gauging a subgroup $ H$ . The continuum classification directly informs the lattice data, such as the generalized gauging that determines the symmetry category, and the data that specifies the gapped phase. We construct commuting projector Hamiltonians and ground states applicable to any non-chiral gapped phase with such symmetries. We also describe the ground states in terms of tensor networks. In light of the length of the paper, we include a self-contained summary section presenting the main results and examples.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph), Quantum Algebra (math.QA), Quantum Physics (quant-ph)
58 pages self-contained summary + 100 pages main text + appendices
Zigzagging Diffusion and Non-Standard Transport in Particle-laden Nanopores Under Extreme Confinement
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
A. Baer, P. Malgaretti, K. Hoellring, J. Harting, Ana-Suncana Smith
Understanding transport subject to molecular-scale confinement is key to advancing nanofluidics, yet classical hydrodynamic laws often fail at these scales. Here, we study a model system: transport of toluene as a solvent and small fullerenes as model particles confined within alumina slit nanopores using molecular dynamics simulations. We find that toluene organizes into discrete layers whose commensurability with the pore width leads to a striking, non-monotonic, zig-zag dependence of transport coefficients on confinement. This layering drives oscillations not only in solvent diffusivity but also in flow velocity and permeability under pressure-driven conditions, breaking the expected scaling relations between diffusion, viscosity, and flow. Surprisingly, introducing a nanoparticle does not wash out these effects - although the fullerene perturbs local layering, the nanoparticle diffusivity retains a zig-zag dependence on pore width. Our results demonstrate how structural commensurability and interfacial effects dominate transport in nanoconfined liquids, and lead to important deviations from continuum expectations. These findings establish a microscopic basis for size-dependent transport in nanopores and highlight the need for beyond-hydrodynamic models in confined soft matter systems.
Soft Condensed Matter (cond-mat.soft)
Tip-Based Proximity Ferroelectric Switching and Piezoelectric Response in Wurtzite Multilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Eugene A. Eliseev, Anna N. Morozovska, Sergei V. Kalinin, Long-Qing Chen, Venkatraman Gopalan
Proximity ferroelectricity is a novel paradigm for inducing ferroelectricity, where a non-ferroelectric polar material, which is unswitchable with an external field below the dielectric breakdown field, becomes a practically switchable ferroelectric in direct contact with a thin switchable ferroelectric layer. Here, we develop a Landau-Ginzburg-Devonshire approach to study the proximity effect of local piezoelectric response and polarization reversal in wurtzite ferroelectric multilayers under a sharp electrically biased tip. Using finite element modeling we analyze the probe-induced nucleation of nanodomains, the features of local polarization hysteresis loops and coercive fields in the Al1-xScxN/AlN bilayers and three-layers. Similar to the wurtzite multilayers sandwiched between two parallel electrodes, the regimes of “proximity switching” (where the multilayers collectively switch) and the regime of “proximity suppression” (where they collectively do not switch) are the only two possible regimes in the probe-electrode geometry. However, the parameters and asymmetry of the local piezo-response and polarization hysteresis loops depend significantly on the sequence of the layers with respect to the probe. The physical mechanism of the proximity ferroelectricity in the local probe geometry is a depolarizing electric field determined by the polarization of the layers and their relative thickness. The field, whose direction is opposite to the polarization vector in the layer(s) with the larger spontaneous polarization (such as AlN), renormalizes the double-well ferroelectric potential to lower the steepness of the switching barrier in the “otherwise unswitchable” polar layers. Tip-based control of domains in otherwise non-ferroelectric layers using proximity ferroelectricity can provide nanoscale control of domain reversal in memory, actuation, sensing and optical applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
30 pages, including 7 figures and Appendixes
Anomalous localization of light in one-dimensional Lévy photonic lattices
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-12 20:00 EDT
Alejandro Ramírez-Yañez, Thomas Gorin, Rodrigo A. Vicencio, Víctor A. Gopar
Localization of coherent propagating waves has been extensively studied over the years, primarily in homogeneous random media. However, significantly less attention has been given to wave localization in inhomogeneous systems, where the standard picture of Anderson localization does not apply, as we demonstrate here. We fabricate photonic lattices with inhomogeneous disorder, modeled by heavy-tailed $ \alpha$ -stable distributions, and measure the output light intensity profiles. We demonstrate that the spatial localization of light is described by a stretched exponential function, with a stretching parameter $ \alpha$ , and an asymmetric localized profile with respect to the excitation site. We support our experimental and theoretical findings with extensive tight-binding simulations.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Optics (physics.optics)
Includes supplemental material
Tuning excitons and superfluidity of dipolar excitons in the double layers of kagome lattice by applying circularly polarized irradiation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Sita Kandel, Godfrey Gumbs, Teresa lee, Oleg L. Berman
We present detailed calculations for several significant properties of the kagome lattice. We employ the Floquet-Magnus perturbation expansion to obtain the energy bands and the corresponding wave functions near the Dirac points for the kagome lattice in the presence of circularly or linearly polarized irradiation. In contrast with linearly polarized irradiation, a band gap is opened up near the Dirac points, between the valence and conduction bands in the presence of circularly polarized irradiation. We calculated the exciton binding energy, and the exciton energy for gapped kagome lattice as a function of the frequency and intensity of the irradiation. We compare the exciton binding energy and exciton energy in a monolayer with those in a double layer separated by an insulator to inhibit recombination. We predict that a phase transition in the kagome lattice from the semiconducting phase to the excitonic insulating phase can be induced by applying irradiation. We also examined the conditions for such a phase transition. We explore opportunities to tune exciton binding energy, the energy spectrum of collective excitations, the sound velocity and the critical temperature of the superfluidity by applying circularly polarized irradiation. We propose observation of Bose-Einstein condensation and superfluidity of quasi-two-dimensional dipolar excitons in two-layer kagome lattices in the presence of pumping by circularly polarized light. We have also analyzed the dependence of superfluid density $ n_s$ and the temperature of the Kosterlitz-Thouless phase transition temperature on excitonic density n, the interlayer separation D and the parameters for circularly polarized light.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Putative excitonic insulating state in narrow-gap semiconductor La$_3$Cd$_2$As$_6$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Caitlin S. Kengle, Noah Schnitzer, Elizabeth A. Peterson, Chunyu Guo, Ling Zhang, Matthew S. Cook, Jian-Xin Zhu, Sean M. Thomas, Philip J. W. Moll, Filip Ronning, Priscila F.S. Rosa
Excitonic insulators are electronically-driven phases of matter characterized by the spontaneous condensation of electron-hole pairs. Here we show that La$ _3$ Cd$ 2$ As$ 6$ undergoes a transition at $ T{0}=278$ K to a highly insulating state with no accompanying structural transition. We observe quasi-two-dimensional electrical transport and charge fluctuations consistent with an electronic transition enabled by enhanced Coulomb interactions. Density functional theory calculations are unable to replicate the insulating ground state. Our results support the opening of a gap by excitonic effects at $ T{0}$ , placing La$ _3$ Cd$ _2$ As$ _6$ as a rare example of a bulk excitonic insulator.
Strongly Correlated Electrons (cond-mat.str-el)
LA-UR-25-25525
Electron mobility in AlN from first principles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Amanda Wang, Nick Pant, Woncheol Lee, Jie-Cheng Chen, Feliciano Giustino, Emmanouil Kioupakis
Aluminum nitride is a promising ultra-wide band gap semiconductor for optoelectronics and power electronics. However, its practical applications have been limited by challenges with doping and achieving high electrical conductivity. Recent advances in crystal quality and defect control have led to improvements in experimentally measured mobilities. In this work, we apply first-principles calculations to determine the upper limits of the electron mobility in AlN as a function of temperature, doping, and crystallographic orientation. We account for the combined effects of electron scattering by phonons and ionized impurity to model doped systems, and examine both full and partial ionization conditions. Our results show that the piezoelectric interaction from the long-range component of the acoustic modes is the dominant source of electron-phonon scattering at room temperature. Ionized-impurity scattering starts to dominate scattering at dopant concentrations above $ 10^{16}$ cm$ ^{-3}$ , reducing the mobility by more than an order of magnitude in the high doping regime. Our calculated Hall mobility values are in good agreement with experimental data for samples with comparable dopant concentrations. We also find that electron mobilities as high as $ 956$ cm$ ^2$ /V$ \cdot$ s could be achievable at lower dopant concentrations.
Materials Science (cond-mat.mtrl-sci)
18 pages, 2 figures in main text, 2 in supplementary
Aluminum oxide coatings on Co-rich cathodes and interactions with organic electrolyte
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
M.D. Hashan C. Peiris, Michael Woodcox, Diana Liepinya, Robert Shephard, Hao Liu, Manuel Smeu
Lithium-ion batteries (LIBs) have become essential in modern energy storage; however, their performance is often limited by the stability and efficiency of their components, particularly the cathode and electrolyte. Transition metal layered oxide cathodes, a popular choice for lithium-ion batteries (LIBs), suffer from several degradation mechanisms, including capacity fading, reactions with the electrolyte, unstable cathode-electrolyte interfaces, and lattice breakdown during cycling. In recent years, oxide coating, such as alumina, has emerged as a promising strategy to enhance the durability of cathodes by forming a protective layer that mitigates detrimental reactions and improves the stability of the cathode electrolyte interphase (CEI). This study employs ab initio molecular dynamics (AIMD) simulations to investigate the chemical and mechanical behavior of LiCoO2 cathodes with and without aluminum oxide coatings in contact with an organic electrolyte. We examine the interactions between electrolyte molecules with both bare and coated cathode surfaces, focusing on the decomposition of ethylene carbonate (EC) and dimethyl carbonate (DMC), the formation of oxygen species, and solvation dynamics, and evaluate the mechanical robustness of the cathode-coating interface using calculations of axial strain and cleavage energy. Our findings reveal that alumina coatings effectively reduce electrolyte degradation and stabilize the cathode structure, particularly under high-charge states. The coating’s thickness and structural orientation are crucial in enhancing mechanical strength and minimizing detrimental reactions at the cathode-electrolyte interface. These insights contribute to the development of more durable LIBs by optimizing the interface chemistry and mechanical properties, providing a pathway toward higher energy densities and longer cycle life.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Submitted for NIST Internal Review
Comparing classical and machine learning force fields for modeling deformation of solid sorbents relevant for direct air capture
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Logan M. Brabson, Andrew J. Medford, David S. Sholl
Direct air capture (DAC) with solid sorbents such as metal-organic frameworks (MOFs) is a promising approach for negative carbon emissions. Computational materials screening can help identify promising materials from the vast chemical space of potential sorbents. Experiments have shown that MOF framework flexibility and deformation induced by adsorbate molecules can drastically affect adsorption properties such as capacity and selectivity. Force field (FF) models are commonly used as surrogates for more accurate density functional theory (DFT) calculations when modeling sorbents, but most studies using FFs for MOFs assume framework rigidity to simplify calculations. Although flexible FFs for MOFs have been parameterized for specific materials, the generality of FFs for reliably modeling adsorbate-induced deformation to near-DFT accuracy has not been established. This work benchmarks the efficacy of several general FFs in describing adsorbate-induced deformation for DAC against DFT. Specifically, we compare a common classical FF (UFF4MOF) with several machine learning (ML) FFs: M3GNet, CHGNet, MACE-MP-0, MACE-MPA-0, eSEN, and the Equiformer V2 model developed from the recent Open DAC 2023 dataset. Our results show that current classical methods are insufficient for describing framework deformation, especially in cases of interest for DAC where strong interactions exist between adsorbed molecules and MOF frameworks. The emerging ML methods we tested – particularly CHGNet, MACE-MP-0, and Equiformer V2 – appear to be more promising than the classical FF for emulating the deformation behavior described by DFT but fail to achieve the accuracy required for practical predictions.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Spin-lattice entanglement in $\mathbf{CoPS}_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Thuc T. Mai, Amber McCreary, K.F. Garrity, Rebecca L. Dally, Sambridhi Shah, Bryan C. Chakoumakos, Md Nasim Afroj Taj, Jeffrey W. Lynn, Michael A. McGuire, Benjamin S. Conner, Mona Zebarjadi, Janice L. Musfeldt, Angela R. Hight Walker, Rahul Rao, Michael A. Susner
Complex chalcogenides in the $ M$ PS$ _3$ family of materials ($ M$ = Mn, Fe, Co, and Ni) display remarkably different phase progressions depending upon the metal center orbital filling, character of the P-P linkage, and size of the van der Waals gap. There is also a stacking pattern and spin state difference between the lighter and heavier transition metal-containing systems that places CoPS$ _3$ at the nexus of these activities. Despite these unique properties, this compound is under-explored. Here, we bring together Raman scattering spectroscopy and infrared absorption spectroscopy with X-ray techniques to identify a structural component to the 119 K magnetic ordering transition as well as a remarkable lower temperature set of magnon-phonon pairs that engage in avoided crossings along with a magnetic scattering continuum that correlates with phonon lifetime effects. These findings point to strong spin-phonon entanglement as well as opportunities to control these effects under external stimuli.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
12 pages, 5 figures
Correlated Electrons and Magnetism in Double Perovskites
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Gayanath W. Fernando, Saikat Banerjee, R. Matthias Geilhufe
This paper is an overview of some recent work done on the double perovskites. We discuss the physics of selected double perovskite compounds emphasizing the relevant interactions and resulting observable phenomena such as the magnetic order using different theoretical approaches. Spin-Orbit interaction, which is comparable to other relevant interaction strengths, plays a central role in determining the physics of such 4d-5d perovskites.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages + 5 Figures
Quantum Algorithm Software for Condensed Matter Physics
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
This report offers a comprehensive analysis of the evolving landscape of quantum algorithm software specifically tailored for condensed matter physics. It examines fundamental quantum algorithms such as Variational Quantum Eigensolver (VQE), Quantum Phase Estimation (QPE), Quantum Annealing (QA), Quantum Approximate Optimization Algorithm (QAOA), and Quantum Machine Learning (QML) as applied to key condensed matter problems including strongly correlated systems, topological phases, and quantum magnetism. This review details leading software development kits (SDKs) like Qiskit, Cirq, PennyLane, and Q#, and profiles key academic, commercial, and governmental initiatives driving innovation in this domain. Furthermore, it assesses current challenges, including hardware limitations, algorithmic scalability, and error mitigation, and explores future trajectories, anticipating new algorithmic breakthroughs, software enhancements, and the impact of next-generation quantum hardware. The central theme emphasizes the critical role of a co-design approach, where algorithms, software, and hardware evolve in tandem, and highlights the necessity of standardized benchmarks to accelerate progress towards leveraging quantum computation for transformative discoveries in condensed matter physics.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)
comprehensive analysis of the quantum algorithm software in condensed matter physics
Surrogate models to optimize plasma assisted atomic layer deposition in high aspect ratio features
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Angel Yanguas-Gil, Jeffrey W. Elam
In this work we explore surrogate models to optimize plasma enhanced atomic layer deposition (PEALD) in high aspect ratio features. In plasma-based processes such as PEALD and atomic layer etching, surface recombination can dominate the reactivity of plasma species with the surface, which can lead to unfeasibly long exposure times to achieve full conformality inside nanostructures like high aspect ratio vias. Using a synthetic dataset based on simulations of PEALD, we train artificial neural networks to predict saturation times based on cross section thickness data obtained for partially coated conditions. The results obtained show that just two experiments in undersaturated conditions contain enough information to predict saturation times within 10% of the ground truth. A surrogate model trained to determine whether surface recombination dominates the plasma-surface interactions in a PEALD process achieves 99% accuracy. This demonstrates that machine learning can provide a new pathway to accelerate the optimization of PEALD processes in areas such as microelectronics. Our approach can be easily extended to atomic layer etching and more complex structures.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG), Plasma Physics (physics.plasm-ph)
Droplet-gas phases and their dynamical formation in particle imbalanced mixtures
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-12 20:00 EDT
Jose Carlos Pelayo, George A. Bougas, Thomás Fogarty, Thomas Busch, Simeon I. Mistakidis
We explore the ground state phase diagram and nonequilibrium dynamics of genuine two-component particle-imbalanced droplets in both isotropic and anisotropic three-dimensional confinements. A gradual transition from mixed droplet-gas to gas configurations is revealed as the average intercomponent attraction decreases or the transverse confinement becomes tighter. Within the mixed structures, a specific majority fragment binds to the minority droplet, satisfying the density ratio locking condition, while the remaining atoms are in a gas state. Our extended Gross-Pitaevskii numerical results are corroborated by a suitable variational approximation capturing the shape and characteristics of droplet-gas fragments. The tunability of the relatively low gas fraction is showcased through parametric variations of the atom number, the intercomponent imbalance, the trap aspect ratio, or the radius of a box potential. To validate the existence and probe the properties of these exotic phases, we simulate the standard time-of-flight and radio frequency experimental techniques. These allow to dynamically identify the resilience of the droplet fragment and the expansion of the gas fraction. Our results, amenable to current experimental cold atom settings, are expected to guide forthcoming investigations aiming to reveal unseen out-of-equilibrium droplet dynamics.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Engineering topological phase transitions via sliding ferroelectricity in MBi2Te4 (M = Ge, Sn, Pb) bilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Xinlong Dong, Dan Qiao, Zeyu Li, Zhenhua Qiao, Xiaohong Xu
Materials combining electrically switchable ferroelectricity and tunable topological states hold significant promise for advancing both foundamental quantum phenomena and innovative device architectures. Here, we employ first-principles calculations to systematically investigate the sliding ferroelectricity-mediated topological transitions in bilayer MBi2Te4 (M = Ge, Sn, Pb). By strategically engineering interlayer sliding configurations with oppositely polarized states, we demonstrate reversible band inversion accompanied by topological phase transitions. The calculated spin-orbit-coupled bandgaps reach 31 meV (GeBi2Te4), 36 meV (SnBi2Te4), and 35 meV (PbBi2Te4), thereby enabling room-temperature observation of the quantum spin Hall effect. Crucially, these systems exhibit substantial out-of-plane ferroelectric polarization magnitudes of 0.571-0.623 pC/m, with PbBi2Te4 showing the maximum polarization (0.623 pC/m). The topological nontriviality is unambiguously confirmed by two independent signatures: (i) the computed z2 topological invariant, and (ii) the emergence of gapless helical edge states spanning the bulk insulating gap. This synergy arises from the unique sliding-induced charge redistribution mechanism, which simultaneously modulates Berry curvature and breaks in-plane inversion symmetry without disrupting out-of-plane polarization stability. The co-engineering of non-volatile ferroelectric switching and topologically protected conduction channels in MBi2Te4 bilayers establishes a material paradigm for designing reconfigurable quantum devices, where electronic topology can be electrically controlled via polarization reversal. Our results provide critical insights into manipulating correlated quantum states in van der Waals ferroelectrics for multifunctional nanoelectronics.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Computational Physics (physics.comp-ph)
Bose-Einstein Condensates in a Synthetic Magnetic Field with Tunable Orientation
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-12 20:00 EDT
Fengtao Pang, Huaxin He, Yongping Zhang, Chunlei Qu
We systematically investigate the ground state and dynamics of spinor Bose-Einstein condensates subject to a position-dependent detuning. This detuning induces three related quantities-a synthetic magnetic field, an angular velocity, and an angular momentum-which, due to trap anisotropy, may point in different directions. When the dipole frequencies along the three symmetric axes of the harmonic trap are degenerate, the dipole motion can decompose into two coupled transverse modes in the plane perpendicular to the synthetic magnetic field, and another decoupled longitudinal mode, enabling controllable Foucault-like precession or bi-conical trajectories depending on the excitation protocol. Furthermore, quenching the orientation of the synthetic magnetic field excites multiple coupled quadrupole modes. We develop a hydrodynamic theory whose predictions match well with Gross-Pitaevskii simulations. This study contributes to a deeper understanding of the effects of the synthetic magnetic field and the excitations of the collective mode in quantum fluids, providing a foundation for future developments in quantum simulation and high-precision sensing technologies.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
14 Pages, 7 Figures
Collective Oscillations of Bose-Einstein Condensates in a Synthetic Magnetic Field
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-12 20:00 EDT
Huaxin He, Fengtao Pang, Yongping Zhang, Chunlei Qu
We study the collective oscillations of spin-orbit-coupled Bose-Einstein condensates in the presence of position-dependent detuning. Specifically, we explore the quadrupole modes of the system using both numerical and analytical approaches based on the Gross-Pitaevskii equation and hydrodynamic theory. Due to spin-orbit coupling and the synthetic magnetic field, {the $ xy$ scissors mode couples with a superposition of the three diagonal quadrupole modes ($ x^2$ , $ y^2$ , and $ z^2$ ),} resulting in the characteristic beating effect. {The remaining two scissors modes, $ xz$ and $ yz$ , are coupled, giving rise to a Lissajous-like pattern that is highly sensitive to the excitation method and orientation of the synthetic magnetic field.} Furthermore, we find that anisotropic interactions as well as the direction of the synthetic magnetic field, can significantly influence the oscillation amplitude and frequency of the quadrupole modes. These findings highlight the potential of Bose-Einstein condensates under synthetic magnetic fields for quantum sensing applications, such as magnetic field {gradient} measurements, and provide a promising foundation for future experimental research and technological development.
Quantum Gases (cond-mat.quant-gas)
11 Pages, 6 Figures
Physical Review Research 7, 013219 (2025)
Optimizing Atomic Number Contrast in Multislice Electron Ptychography
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Bridget R. Denzer, Colin Gilgenbach, James M. LeBeau
Here we explore the atomic number ($ Z$ ) dependence of multislice electron ptychography and approaches to optimize Z sensitivity. Specifically, we show that ptychography’s $ Z$ -dependence is highly dependent on the integrated area of an atom column considered. A monotonic $ Z$ -dependence is found when the reconstructed projected atomic potentials are integrated over a small region. When increasing the integration area, $ Z$ -contrast changes significantly, becoming highly non-monotonic and following trends in the orbital shell-structure. Moreover, the reconstructed projected potential aligns with the transmission function with an overall deviation of only 2.4%. The non-monotonic $ Z$ -dependence is further shown to be useful to accentuate contrast between certain elements, allowing for distinguishability of elements that are only a single atomic number apart, and even in $ >$ 20 nm thick samples. This is demonstrated for $ \beta$ -CuZn ($ Z$ = 29 and 30), with the differentiability between the elements explored for different signal quantification methods. The impact of electron dose and finite effective source size are also considered. These results demonstrate that the atom column integration area can optimize ptychographic $ Z$ -contrast for specific applications and experimental conditions.
Materials Science (cond-mat.mtrl-sci), Atomic Physics (physics.atom-ph)
Molecular Dynamics Simulations of SrTiO$_3$ with Oxygen Vacancies using Neural Network Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Kazutaka Nishiguchi, Ryota Yamamoto, Meguru Yamazaki, Naoki Matsumura, Yuta Yoshimoto, Seiichiro L. Ten-no, Yasufumi Sakai
A precise analysis of point defects in solids requires accurate molecular dynamics (MD) simulations of large-scale systems. However, ab initio MD simulations based on density functional theory (DFT) incur high computational cost, while classical MD simulations lack accuracy. We perform MD simulations using a neural network potential (NNP) model (NNP-MD) to predict the physical quantities of both pristine SrTiO$ _3$ and SrTiO$ _3$ in the presence of oxygen vacancies (V$ _{\text{O}}$ ). To verify the accuracy of the NNP models trained on different data sets, their NNP-MD predictions are compared with the results obtained from DFT calculations. The predictions of the total energy show good agreement with the DFT results for all these NNP models, and the NNP models can also predict the formation energy once SrTiO$ _3$ :V$ _{\text{O}}$ data are included in the training data sets. Even for larger supercell sizes that are difficult to calculate using first-principles calculations, the formation energies evaluated from the NNP-MD simulations well reproduce the extrapolated DFT values. This study offer important knowledge for constructing accurate NNP models to describe point-defect systems including SrTiO$ _3$ :V$ _{\text{O}}$ .
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
20 page, 7 figures
Phase Evolution and Substrate-Dependent Nucleation of Quartz GeO$_2$ Films Grown by MOCVD on r- and c-Plane Sapphires
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Botong Li, Imteaz Rahaman, Hunter Ellis, Bobby G. Duersch, Kathy Anderson, Kai Fu
Ultrawide-bandgap (UWBG) semiconductors, such as GeO$ _2$ , are gaining significant attention for their potential in high-performance applications, particularly in piezoelectric devices. Despite extensive research, a comprehensive understanding of the growth dynamics and phase evolution of GeO$ _2$ films via metal-organic chemical vapor deposition (MOCVD) remains insufficient. In this study, we investigate the growth behavior and morphological evolution of GeO$ _2$ thin films on r-plane and c-plane sapphire substrates for the MOCVD growth process. The temporal evolution of crystallization and the amorphous-to-quartz phase transition are systematically elucidated for the first time. As growth time increases, the spherulitic quartz patterns expand in size, and elevated growth temperatures are found to enhance the crystallization rate. Distinct morphological symmetries emerge depending on the substrate orientation: quadrangular patterns on r-plane sapphire and hexagonal patterns on c-plane sapphire. Atomic force microscopy reveals that these spherulitic domains exhibit pyramid-like surface topography, consistent with volumetric contraction during the amorphous-to-quartz phase transition. These findings offer new insights into the phase evolution and substrate-dependent crystallization behavior of GeO$ _2$ films grown by MOCVD.
Materials Science (cond-mat.mtrl-sci)
18 pages, 7 figures, 1 Table
Ferroelectric control of bipolar magnetic semiconductor with room Curie temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
The development of room-temperature tunable magnetic semiconductors is crucial for the advancement of low-power, high-performance information technologies. Using density functional theory calculations, we propose a series of two-dimensional magnetic semiconductors with critical temperature above room temperature, including three ferromagnetic and two antiferromagnetic this http URL stability is confirmed through phonon spectra, molecular dynamics simulations, and formation energy calculations. In particular, we demonstrate a ferromagnetic bipolar magnetic semiconductor (BMS), Cr2NiSe4, formed via Ni intercalation into bilayer CrSe2, which exhibits a 0.40 eV band gap and a Curie temperature of 352 K. Nonvolatile carrier spin polarization control in Cr2NiSe4 is achieved by switching the ferroelectric polarization of an Al2Se3 substrate. Switching the ferroelectric state of monolayer Al2Se3 induces a BMS-to-half-metal transition. Reversing the polarization of bilayer Al2Se3 yields a half-metallic Cr2NiSe4 with fully opposite carrier spin polarization. Furthermore, we propose a multiferroic nonvolatile memory design: write operations are controlled by the ferroelectric polarization state of bilayer Al2Se3, while read operations rely on detecting the distinct carrier spin polarizations of Cr2NiSe4. Our work reports a two dimensional BMS with Curie temperature above room temperature and presents a feasible strategy for its nonvolatile electrical control.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Ising superconductivity in bulk layered non-centrosymmetric 4H-NbSe2
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-12 20:00 EDT
Chandan Patra, Tarushi Agarwal, Rahul Verma, Poulami Manna, Shashank Srivastava, Ravi Shankar Singh, Mathias S. Scheurer, Bahadur Singh, Ravi Prakash Singh
Transition metal dichalcogenides exhibit multiple polymorphs that enable the exploration of diverse quantum states, including valley-selective spin polarization, the valley Hall effect, Ising superconductivity, and nontrivial topology. Monolayer 2$ H$ -NbSe$ _2$ is a promising candidate for realizing Ising superconductivity due to its spin-split, out-of-plane spin-polarized states arising from inversion symmetry breaking and strong spin-orbit coupling. In contrast, bulk 2$ H$ -NbSe$ _2$ retains inversion symmetry and lacks spin splitting, limiting its suitability for hosting Ising superconductivity. Here, we report the growth of high-quality single crystals of the acentric bulk superconducting polymorph, 4$ H$ -NbSe$ _2$ , which intrinsically breaks the inversion symmetry and supports valley-selective spin-polarized states. Magnetization and resistivity measurements reveal anisotropic superconductivity, with the in-plane upper critical field exceeding the Pauli limit, while out-of-plane fields suppress superconductivity more rapidly, before reaching the Pauli limit, which strongly suggests the presence of Ising pairing. First-principles calculations and symmetry analysis confirm significant valley-selective spin splitting with out-of-plane spin polarization, further supporting the emergence of Ising superconductivity in 4$ H$ -NbSe$ _2$ . These results establish 4$ H$ -NbSe$ _2$ as a robust bulk platform to investigate Ising superconductivity and valley-selective phenomena in transition-metal dichalcogenides.
Superconductivity (cond-mat.supr-con)
8 Pages, 4 figures
Unusual Valence of Ru and Prediction of Magnetism, Anomalous Hall Conductivity in a Newly Synthesized Double Perovskite Compound Ca_2CoRuO_6
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Koushik Pradhan, Soumya Ghorai, Prabuddha Sanyal, Ryan Morrow, Bernd Büchner, Thirupathaiah Setti, Tanusri Saha Dasgupta
With a goal to expand on the family of double perovskite compounds, hosting 3d transition metal and 4d or 5d transition metal, two new ordered double perovskite compounds, Ca$ _2$ FeRuO$ _6$ and Ca$ _2$ CoRuO$ _6$ are synthesized following the prediction of a recent high throughput machine-learning study [Phys. Rev. Materials 3, 084418]. Experimentally both compounds are found to stabilize in monoclinic symmetry, which is consistent with the high-throughput prediction for Ca$ _2$ FeRuO$ _6$ , but at odd for Ca$ _2$ CoRuO$ _6$ . Among the two synthesized compounds, the properties of Ca$ _2$ CoRuO$ _6$ , investigated employing the first principles technique \textcolor{black}{and model Hamiltonian calculation}, appear promising. The monoclinic structured Ca$ _2$ CoRuO$ _6$ is found to stabilize unusual 6+ valence of Ru, and support a half-metallic ground state with uncompensated net moment. As \textcolor{black}{predicted} by our first-principles study, the finite spin-orbit coupling at the Ru site contributes to the non-trivial topology of the band structure of monoclinic Ca$ _2$ CoRuO$ _6$ , resulting in a \textcolor{black}{moderately} large value of anomalous Hall conductivity. Our \textcolor{black}{theoretical predictions} should encourage further experimental investigation of this newly synthesized compound.
Materials Science (cond-mat.mtrl-sci)
18 pages, 15 figs
The role of small-angle electron-electron scattering in transverse magnetic focusing experiment
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Dmitry A. Egorov, Dmitriy A. Pokhabov, Evgeny Yu. Zhdanov, Andrey A. Shevyrin, Askhat K. Bakarov, Alexander A. Shklyaev, Arthur G. Pogosov
We demonstrate the crucial role of small-angle scattering in transverse magnetic focusing (TMF) in ballistic GaAs/AlGaAs heterostructures. Measurements in various samples show that the role significantly depends on their geometry. We propose a phenomenological model parameterizing this dependence with the angular acceptance of the detecting contact. This model is consistent with the diversity of experimental data and therefore enables accurate extraction of the key characteristic of inter-electron (e-e) interaction $ \unicode{x2013}$ the e-e scattering length $ \unicode{x2013}$ from TMF experiment, thus turning it into a uniquely effective tool for studying e-e scattering.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 4 figures
Stability, electronic, magnetic and thermoelectric properties of quaternary Heusler alloys CoX’ZrAl (X’=V, Fe, Ir): 3d vs 5d systems
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Poulami Biswas, Mahabubur Rahaman, Molly De Raychaudhury
The thermoelectric (TE) properties of quaternary Heusler alloys (CoX’ZrAl; X’= V, Fe, Ir) are studied in the framework of Density Functional Theory and Boltzmann Transport Theory. The compound CoVZrAl is found to be semiconducting and the most difficult to be formed whereas the easier formed newly-predicted CoFeZrAl and CoIrZrAl are pseudo-gapped and half-metal respectively. Ferromagnetic calculations show magnetism in CoVZrAl and CoIrZrAl originating from the non-bonding Co-X’ fully-filled t1u state and partially-filled eu state derived from Co-3d and X’-3d and 5d electrons respectively while CoFeZrAl is non-magnetic. The two-dimensional graphene-like density of states at the Fermi level in CoFeZrAl implies large electrical conductivity. We further observe that the presence of two 3d early Transition metal (TM) atoms enhances the Seebeck coefficient as in CoVZrAl and CoFeZrAl and the presence of extended 5d state of Ir diminishes the same for CoIrZrAl. However the higher thermal conductivity in CoFeZrAl renders CoVZrAl the best TE material among the three. The ZT value of n-type CoVZrAl is found to reach a higher value 1.4 at 600 K.
Materials Science (cond-mat.mtrl-sci)
Anisotropic In-plane Thermal Conductivity of Freestanding Few-layer ReS2
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Manavendra Pratap Singh, Akshay Naik
Rhenium disulfide (ReS2) is a unique TMDC with a strong in-plane anisotropy and weak interlayer coupling. The pronounced anisotropy in the thermal conductivity observed in bulk ReS2 flakes (exceeding 60 nm) makes them valuable for applications that require directional heat management or isolation. Whether this anisotropy is maintained below 10 nm has not yet been studied. Here, we measured the thermal conductivity of freestanding, exfoliated, few-layer ReS2 samples (thickness < 10 nm) on SiO2/Si holey substrates using the optothermal Raman technique. Polarization-dependent Raman measurements revealed variation in thermal conductivity along the high symmetry axes. The total in-plane thermal conductivities show a nonmonotonic trend with ReS2 thickness ranging from 2.5 to 8 nm. The in-plane thermal conductivity of few-layer ReS2 devices, which varies with thickness, holds significant potential for applications in nanoscale thermoelectric devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Efficient broadband terahertz generation by above band-gap excitation of the pyroelectric ZnSnN2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
T. S. Seifert, H. Hempel, O. Gückstock, R. Schneider, Q. Remy, A. Fioretti, T. Unold, S. Michaelis de Vasconcellos, R. Bratschitsch, R. Eichberger, K. Dörr, A. Zakutayev, T. Kampfrath
Terahertz (THz) radiation is a powerful probe of low-energy excitations in all phases of matter. However, it remains a challenge to find materials that efficiently generate THz radiation in a broad range of frequencies following optical excitation. Here, we investigate a pyroelectric material, ZnSnN2, and find that above-band-gap excitation results in the efficient formation of an ultrafast photocurrent generating THz radiation. The resulting THz electric field spans a frequency range from below 1 to above 30 THz. Our results suggest that the photocurrent is primarily driven by an ultrafast pyroelectric effect where the photo-excited carriers screen the spontaneous electric polarization of ZnSnN2. Strong structural disorder reduces the photocarrier lifetime significantly and, thus, enables broadband operation. ZnSnN2 shows similar THz-emitter performance as the best spintronic THz emitters regarding bandwidth and amplitude. Our study unveils the large potential of pyroelectric materials as efficient and broadband THz emitters with built-in bias fields.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Hall effect in isolated flat-band systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Raigo Nagashima, Masao Ogata, Naoto Tsuji
We study the Hall effect in isolated flat-band systems (i.e., a flat band is separated from other bands) for a weak magnetic field. In a naive semiclassical picture, the Hall conductivity vanishes when dispersive bands are unoccupied since there is no mobile carrier. To go beyond the semiclassical picture, we establish a fully quantum mechanical gauge-invariant formula for the Hall conductivity that can be applied to any lattice models. We apply the formula to a general two-band model with one dispersive and one isolated flat band, and find that the total conductivity takes a universal form as an integral of a product of the squared Berry curvature and energy difference between the two bands. In particular, the Hall coefficient can become nonzero in the flat-band systems with broken inversion symmetry. We numerically confirm this Hall effect for an isolated flat-band lattice model on the honeycomb lattice.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5+4 pages, 4+1 figures
Disorder-induced suppression of superconductivity in infinite-layer nickelates
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-12 20:00 EDT
Abhishek Ranna, Romain Grasset, Martin Gonzalez, Kyuho Lee, Bai Yang Wang, Edgar Abarca Morales, Florian Theuss, Zuzanna H. Filipiak, Michal Moravec, Marcin Konczykowski, Harold Y. Hwang, Andrew P. Mackenzie, Berit H. Goodge
The pairing symmetry of superconducting infinite-layer nickelates is a fundamental yet experimentally challenging question. We employ high-energy electron irradiation to induce disorder in superconducting Nd$ _{0.825}$ Sr$ _{0.175}$ NiO$ _2$ thin films and examine the impact of pair-breaking defects on superconductivity and elucidate the nature of the superconducting gap. Our measurements reveal a complete suppression of superconductivity with increasing disorder, suggesting an unconventional, sign-changing order parameter.
Superconductivity (cond-mat.supr-con)
3 figures
Accelerating Resonant Spectroscopy Simulations Using Multi-Shifted Bi-Conjugate Gradient
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Prakash Sharma, Luogen Xu, Fei Xue, Yao Wang
Resonant spectroscopies, which involve intermediate states with finite lifetimes, provide essential insights into collective excitations in quantum materials that are otherwise inaccessible. However, theoretical understanding in this area is often limited by the numerical challenges of solving Kramers-Heisenberg-type response functions for large-scale systems. To address this, we introduce a multi-shifted biconjugate gradient algorithm that exploits the shared structure of Krylov subspaces across spectra with varying incident energies, effectively reducing the computational complexity to that of linear spectroscopies. Both mathematical proofs and numerical benchmarks confirm that this algorithm substantially accelerates spectral simulations, achieving constant complexity independent of the number of incident energies, while ensuring accuracy and stability. This development provides a scalable, versatile framework for simulating advanced spectroscopies in quantum materials.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
6 pages, 4 figures
Charge Ordering in out-of-plane Boron Doped Reduced Graphene Oxide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Saikat Sarkar, Rajarshi Roy, Bikram Kumar Das, Suman Chatterjee, Kalyan Kumar Chattopadhyay
Symmetry-breaking phase transitions analogous to superconductivity (SC), charge ordering (CO) etc. in metal-intercalated graphene are favorable resulting from modified electronic and phonon band structures. Strong carrier-lattice interaction evolved from the out-of-plane soft vibrations with accumulation of charges at the out-of-plane region, can set a favorable environment for CO in graphene system. Here, we employ boron-doped reduced graphene oxide (BG) to acquire charge-ordered state above a transition temperature, T1~97.5 K. Signatures of this state are identified using ab-initio simulations and low temperature electrical transport measurements. The out-of-plane boron groups play a crucial role in reinforcing the electron-phonon coupling (EPC) allowing an ordered-state transition. Temperature-dependent Raman spectroscopy further supports the emergence of ordering. Key characterization techniques (X-ray diffraction, Raman spectra etc.) are used to quantify the EPC interaction and associated factors like tensile strain, boundary defects, etc. affecting charge ordering with doping. Additionally, we find interesting electric field dependency on the CO in this non-metallic, light-atom-doped chemically derived graphene.
Materials Science (cond-mat.mtrl-sci)
Quantitative theory of magnetic properties of elemental praseodymium
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Leonid V. Pourovskii, Alena Vishina, Olle Eriksson, Mikhail I. Katsnelson
Elemental Pr metal crystallizes in the double hexagonal close packed (dhcp) structure and is unique among rare-earth elements in featuring a localized partially filled 4f shell without ordered magnetism. Experimental evidence attributes this absence of magnetism to a singlet crystal-field (CF) ground state of the Pr 4f$ ^2$ configuration, which is energetically well isolated from excited magnetic doublets. Here, we construct a realistic effective magnetic Hamiltonian for dhcp Pr, by combining density-functional theory with dynamical mean-field theory, in the quasiatomic Hubbard-I approximation. Our calculations fully determine the CF potential and predict singlet CF ground states at both inequivalent sites of the dhcp lattice. The intersite exchange interactions, obtained from the magnetic force theorem, are found to be insufficient to close the CF gap to the magnetic doublets. Hence, ab-initio theory is demonstrated to explain the unusual, non-magnetic state of elemental Pr. Extending this analysis to the (0001) surface of Pr, we find that the singlet ground state remains robust preventing conventional magnetic orders. Nevertheless, the gap between the ground state and the lowest excited singlet is significantly reduced at the surface, opening the possibility for exotic two-dimensional multipolar orders to emerge within this two-singlet manifold.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
10 pages, 5 figures + 3 pages of supplementary
Scaling the glassy dynamics of active particles: Tunable fragility and reentrance
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
Puneet Pareek, Peter Sollich, Saroj Kumar Nandi, Ludovic Berthier
Understanding the influence of activity on dense amorphous assemblies is crucial for biological processes such as wound healing, embryogenesis, or cancer progression. Here, we study the effect of self-propulsion forces of amplitude $ f_0$ and persistence time $ \tau_p$ in dense assemblies of soft repulsive particles, a model system that interpolates between particulate active matter and biological tissues. We identify the fluid and glass phases of the three-dimensional phase diagram obtained by varying $ f_0$ , $ \tau_p$ , and the packing fraction $ \phi$ . The morphology of the phase diagram directly accounts for a non-monotonic evolution of the relaxation time with $ \tau_p$ , which is a direct consequence of the crossover in the dominant relaxation mechanism, from glassy to jamming. A second major consequence is the evolution of the glassy dynamics from sub-Arrhenius to super-Arrhenius. We show that this tunable glass fragility extends to active systems analogous observations reported for passive particles. This allows us to apply a dynamic scaling analysis proposed for the passive case, in order to account for our results for active systems. Finally, we discuss similarities between our results and recent findings in the context of computational models of biological tissues.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
11 pages, 5 figures
Identifying Clean and Contaminated Atomic-Sized Gold Contacts under Ambient Conditions Using a Clustering Algorithm
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Guillem Pellicer, Carlos Sabater
Molecular electronics studies have advanced from early, simple single-molecule experiments at cryogenic temperatures to complex and multifunctional molecules under ambient conditions. However, room-temperature environments increase the risk of contamination, making it essential to identify and quantify clean and contaminated rupture traces (i.e., conductance versus relative electrode displacement) within large datasets. Given the high throughput of measurements, manual analysis becomes unfeasible. Clustering algorithms offer an effective solution by enabling automatic classification and quantification of contamination levels. Despite the rapid development of machine learning, its application in molecular electronics remains limited. In this work, we present a methodology based on the DBSCAN (Density-Based Spatial Clustering of Applications with Noise) algorithm to extract representative traces from both clean and contaminated regimes, providing a scalable and objective tool to evaluate environmental contamination in molecular junction experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Pages 11, 5 figures
Accelerating ground-state auxiliary-field quantum Monte Carlo simulations by delayed update and block force-bias update
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Ground-state auxiliary-field quantum Monte Carlo (AFQMC) methods have become key numerical tools for studying quantum phases and phase transitions in interacting many-fermion systems. Despite the broad applicability, the efficiency of these algorithms is often limited by the bottleneck associated with the {\it local update} of the field configuration. In this work, we propose two novel update schemes, the {\it delayed update} and {\it block force-bias update}, both of which can generally and efficiently accelerate ground-state AFQMC simulations. The {\it delayed update}, with a predetermined delay rank, is an elegantly improved version of the {\it local update}, accelerating the process by replacing multiple vector-vector outer products in the latter with a single matrix-matrix multiplication. The {\it block force-bias update} is a block variant of the conventional force-bias update, which is a highly efficient scheme for dilute systems but suffers from the low acceptance ratio in lattice models. Our modified scheme maintains the high efficiency while offering flexible tuning of the acceptance ratio, controlled by the block size, for any desired fermion filling. We apply these two update schemes to both the standard and spin-orbit coupled two-dimensional Hubbard models, demonstrating their speedup over the {\it local update} with respect to the delay rank and block size. We also explore their efficiencies across varying system sizes and model parameters. Our results identify a speedup of $ \sim$ 8$ for systems with $ \sim$ 1600$ lattice sites. Furthermore, we have investigated the broader applications as well as an application diagram of these update schemes to general correlated fermion systems.
Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 10 figures
Dynamic structure factor of a driven-dissipative Bose-Hubbard model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-12 20:00 EDT
Subhanka Mal, Anushree Dey, Kingshuk Adikary, Bimalendu Deb
Dynamic structure factor (DSF) is important for understanding excitations in many-body physics; it reveals information about the spectral and spatial correlations of fluctuations in quantum systems. Collective phenomena like quantum phase transitions of ultracold atoms are addressed by harnessing density fluctuations. Here, we calculate the DSF of a nonequilibrium spinless Bose-Hubbard model (BHM) from the perspective of dissipative phase transition (DPT) in a steady state. Our methodology uses a homogeneous mean-field approximation to make the single-site hierarchy simpler and applies the Lindbladian perturbation method (LPM) to go beyond the single site, limited by the ratio of the inter-site hopping term to the Liouvillian gap as a small parameter. Our results show that the DSF near a DPT point is characteristically different from that away from the transition point, providing a clear density spectral signature of the DPT. In addition to comparing the two numerical frameworks, the mean-field results serve as a benchmark for proof-of-principle robustness of LPM. Despite the numerical difficulty, our methodology provides a computationally accessible route for studying density fluctuations in an open lattice quantum system without requiring large-scale computation.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
10 pages, 5 figures
Temperature gradient-driven motion of magnetic domains in a magnetic metal multilayer by entropic forces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Lin Huang, Joseph Barker, Lekshmi Kailas, Soumyarup Hait, Simon D. Connell, Gavin Burnell, Christopher H. Marrows
We studied the displacement of magnetic domains under temperature gradients in perpendicularly magnetized Ta/[Pt/Co$ _{68}$ B$ _{32}$ /Ir]$ _{\times 10}$ /Pt multilayer tracks with microfabricated Pt heaters/thermometers by magnetic force microscopy (MFM). Subtracting out the effects of the Oersted field from the heating current reveals the pure temperature gradient-driven motion, which is always towards the heater. The higher the thermal gradient along the track (owing to proximity to the heater or larger heater currents), the greater the observed displacements of the domains, up to a velocity of around 1nm/s in a temperature gradient of 20K/$ \mu$ m. Quantitative estimates of the strength of different driving mechanisms show that entropic forces dominate over those arising from the spin Seebeck and spin-dependent Seebeck effects.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Crossover in growth law in the vapor-liquid phase separation inside complex porous medium
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
We employ molecular dynamics simulations to investigate the domain morphology and growth kinetics of a vapor-liquid system embedded within a complex porous medium. By systematically varying the pore structure, we analyze the scaling behavior of correlation functions, structure factors, and domain growth exponents. The structure factor confirms the breakdown of Porod law and the emergence of fractal-like domain boundaries. Our key finding is the clear crossover in the domain growth law, from the classical power-law behavior observed in bulk fluids to a slower, logarithmic regime in highly confined systems. This transition is driven by energy barriers introduced by the porous geometry, which inhibit coarsening dynamics at later time. We provide a scaling analysis which further confirms this crossover and quantitatively connects the growth behavior with the average pore size.
Soft Condensed Matter (cond-mat.soft)
Influence of preparation and architecture on the elastic modulus of polymer networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
Jiting Tian, Jean-Louis Barrat, Walter Kob
The elastic modulus $ G$ of a polymer network depends notably on parameters such as the initial concentration of the monomers before the synthesis ($ \rho_0$ ), the density of the cross-linker, or the topology of the network. Understanding how these factors influence the stiffness of the sample is hampered by the fact that in experiments it is difficult to tune them individually. Here we use coarse-grained molecular dynamics simulations to study how these quantities, as well as excluded volume interactions, affect the elastic modulus of the network. We find that for a regular diamond network, $ G$ is independent of the initial monomer concentration, while for disordered networks (monodisperse or polydisperse) the modulus increases with $ \rho_0$ , at odds with the classical predictions for rubber elasticity. Analysis of the network structure reveals that, for the disordered networks, defects contribute only weakly to the observed increase, and that instead the $ \rho_0$ -dependence of $ G$ can be rationalized by the presence of a pre-strain in the sample. This pre-strain can be quantified by the topological factor introduced in the affine network theory (ANT). Comparison of the disordered networks with their phantom counterparts reveals that weakly crosslinked systems show a stronger $ \rho_0$ -dependence of $ G$ due to an increase in entanglements at higher $ \rho_0$ , and that the polydisperse networks contain more entanglements than the monodisperse ones with the same average strand length. Finally we discuss the quantitative application of ANT to the simulated real networks and their phantom counterparts and conclude that the presence of excluded volume effects must be comprehensively taken into account for reaching a qualitative understanding of the mechanical modulus of the disordered networks.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Electron-phonon couplings in locally disordered materials: The case of hybrid halide perovskites
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Marios Zacharias, George Volonakis, Laurent Pedesseau, Claudine Katan, Feliciano Giustino, Jacky Even
Positional polymorphism in solids refers to distributions of correlated locally disordered unit cells which reflect, on average, the high-symmetry structure observed in diffraction experiments. The standard theory of electron-phonon interactions is unable to account for the temperature-dependent electronic structure of polymorphous materials. A prime example of such materials is hybrid halide perovskites, for which calculations of band gaps at finite temperatures do not agree with experiment. Here, we develop a systematic and accurate methodology to investigate electron-phonon couplings in complex polymorphous materials, demonstrated through calculations of anharmonic phonons and thermally-induced band gap renormalization for a broad family of halide perovskites. Our approach delivers unprecedented agreement with experiment.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
Type III Valley Polarization and Anomalous Valley Hall Effect in Two-Dimensional Non-Janus and Janus Altermagnet Fe2WS2Se2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Yanchao She, Yiding Wang, Hanbo Sun, Chao Wu, Weixi Zhang, Ping Li
Exploiting the valley degree of freedom introduces a novel paradigm for advancing quantum information technology. Currently, the investigation on spontaneous valley polarization mainly focuses on two major types of systems. One type magnetic systems by breaking the time-reversal symmetry, the other is ferroelectric materials through breaking the inversion symmetry. Might there be additional scenarios? Here, we propose to realize spontaneous valley polarization by breaking the mirror symmetry in the altermagnets, named type III valley polarization. Through symmetry analysis and first-principles calculations, we confirm that this mechanism is feasible in Non-Janus Fe2WS2Se2. Monolayer Non-Janus and Janus Fe2WS2Se2 are stable Neel-type antiferromagnetic state with the direct band gap semiconductor. More interestingly, their magnetic anisotropy energy exhibits the rare biaxial anisotropy and a four-leaf clover shape in the xy plane, while the xz and yz planes show the common uniaxial anisotropy. This originated from the fourth-order single ion interactions. More importantly, the valley splitting is spontaneously generated in the Non-Janus Fe2WS2Se2 due to the Mxy symmetry breaking, without requiring the SOC effect. Both the Non-Janus and Janus Fe2WS2Se2 exhibit diverse valley polarization and anomalous valley Hall effect properties. In addition, the magnitude and direction of valley polarization can be effectively tuned by the biaxial strain and magnetic field. Our findings not only expand the realization system of spontaneous valley polarization, but also provide a theoretical basis for the high-density storage of valley degrees of freedom.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 7 figures
Magnetic phases and zone-folded phonons in a frustrated van der Waals magnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
A. Pawbake, F. Petot, F. Le Mardelé, T. Riccardi, J. Lévêque, B.A. Piot, M. Orlita, J. Coraux, M. Hubert, J. Dzian, M. Veis, Y. Skourski, B. Wu, Z. Sofer, B. Grémaud, A. Saúl, C. Faugeras
2D magnetic materials have attracted extensive research interest due to their potential application in nanospintronics, optospintronics, and in magnonics. Ferromagnetic as well as antiferromagnetic layered materials have been demonstrated and successfully inserted into van der Waals heterostructures. However, the effects of magnetic frustration in van der Waals materials and the possibilities offered by spin configurations characterized by nonlinear spin arrangements have not been fully considered yet. Herein, we establish the magnetic phase diagram of bulk CrOCl, a frustrated van der Waals magnet, using magnetization and magneto-optical spectroscopy techniques. In particular, we use the magnetic superstructures relative to the crystallographic unit cell and the associated rich zone-folded phonon series to describe the magnetic field induced phases. Theoretical calculations taking into account the competing nearest neighbors magnetic exchange interactions provide a unique insight into the lattice vibrations of this class of magnetic system. This study expands the scope of 2D magnetic materials and provides a methodology to characterize frustrated van der Waals magnets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
23 page, 5 figures
Asymmetric Electronic Band Alignment and Potentially Enhanced Thermoelectric Properties in Phase-Separated Mg2X (X=Si,Ge,Sn) Alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Byungki Ryu, Samuel Foster, Eun-Ae Choi, Sungjin Park, Jaywan Chung, Johannes de Boor, Pawel Ziolkowski, Eckhard Müller, Seung Zeon Han, SuDong Park, Neophytos Neophytou
The Mg2X (X=Si, Ge, Sn) based alloy is an eco-friendly thermoelectric material for mid-temperature applications. The Mg2Si1-xSnx and Mg2Ge1-xSnx alloys can be phase-separated into Si(Ge)- and Sn-rich phases during material synthesis, leading to a nanocomposite with locally varying electronic band structure. First-principles calculations reveal that the valence band offset is eight-times larger than the conduction band offset at the interface between Si- and Sn-rich phases for x=0.6, showing type-I and asymmetric band alignment (0.092 eV versus 0.013 eV). Using Boltzmann transport theory and thermionic emission calculations, we show that the large valence band energy discontinuity could allow for energy filtering effects to take place that can potentially increase the power factor substantially in the p-type material system if designed appropriately.
Materials Science (cond-mat.mtrl-sci)
21 pages, 3 figures
Binary Mixtures of Intelligent Active Brownian Particles with Visual Perception
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
Rajendra Singh Negi, Roland G. Winkler, Gerhard Gompper
The collective properties of a binary mixture of A- and B-type self-steering particles endowed with visual perception are studied by computer simulations. Active Brownian particles are employed with an additional steering mechanism, which enables them to adjust their propulsion direction relative to the instantaneous positions of neighboring particles, depending on the species, either steering toward or away from them. Steering can be nonreciprocal between the A- and B-type particles. The underlying dynamical and structural properties of the system are governed by the strength and polarity of the maneuverabilities associated with the vision-induced steering. The model predicts the emergence of a large variety of nonequilibrium behaviors, which we systematically characterize for all nine principal sign combinations of AA, BB, AB and BA maneuverabilites. In particular, we observe the formation of multimers, encapsulated aggregates, honeycomb lattices, and predator-prey pursuit. Notably, for a predator-prey system, the maneuverability and vision angle employed by a predator significantly impacts the spatial distribution of the surrounding prey particles. For systems with electric-charge-like interactions and non-stochiometric composition, we obtain at intermediate activity levels an enhanced diffusion compared to non-steering active Brownian particles.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biological Physics (physics.bio-ph)
13 figures
Rock-salt ScN(113) layers grown on AlN$(11\bar{2}2)$ by plasma-assisted molecular beam epitaxy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Duc V. Dinh, Esperanza Luna, Oliver Brandt
Transition-metal nitrides constitute a versatile class of materials with diverse properties and wide-ranging applications. Exploring new surface orientations and uncovering novel properties can enable innovative material configurations with tailored functionalities for device integration. Here, we report the growth and characterization of (85-210)-nm-thick undoped ScN layers on AlN$ (11\bar{2}2)$ /Al$ {2}$ O$ {3}$ (10\bar{1}0)$ templates via plasma-assisted molecular beam epitaxy. X-ray diffractometry and transmission electron microscopy confirm a pure (113) surface orientation with rotational twins. Two distinct in-plane relationships between ScN(113) and AlN$ (11\bar{2}2)$ have been identified: the dominant $ [1\bar{1}0]{\mathrm{ScN}} \parallel [\bar{1}\bar{1}23]{\mathrm{AlN}}$ and $ [33\bar{2}]{\mathrm{ScN}} \parallel [1\bar{1}00]{\mathrm{AlN}}$ (under tensile-compression), and the less prevalent $ [\bar{1}\bar{2}1]{\mathrm{ScN}} \parallel [1\bar{1}00]{\mathrm{AlN}}$ and $ [7\bar{4}\bar{1}]{\mathrm{ScN}} \parallel [\bar{1}\bar{1}23]{\mathrm{AlN}}$ (under biaxial compression). Broad photoluminescence spectra with a peak emission energy of $ \approx 2.16,\mathrm{eV}$ originate from the lowest direct gap at the $ \mathbf{X}$ point of the ScN band structure. Temperature-dependent Hall-effect measurements (4-380 K) reveal that impurity band conduction dominates. The electron mobility is primarily limited by optical phonon scattering, characterized by an effective phonon energy of $ (60 \pm 3),\mathrm{meV}$ .
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Magnon-polaron control in a surface magnetoacoustic wave resonator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Kevin Künstle, Yannik Kunz, Tarek Moussa, Katharina Lasinger, Kei Yamamoto, Philipp Pirro, John F. Gregg, Akashdeep Kamra, Mathias Weiler
Strong coupling between distinct quasiparticles in condensed matter systems gives rise to hybrid states with emergent properties. We demonstrate the hybridization of confined phonons and finite-wavelength magnons, forming a magnon-polaron cavity with tunable coupling strength and spatial confinement controlled by the applied magnetic field direction. Our platform consists of a low-loss, single-crystalline yttrium iron garnet (YIG) film coupled to a zinc oxide (ZnO)-based surface acoustic wave (SAW) resonator. This heterostructure enables exceptionally low magnon-polaron dissipation rates below $ \kappa / 2\pi < 1.5;$ MHz. The observed mode hybridization is well described by a phenomenological model incorporating the spatial profiles of magnon and phonon modes. Furthermore, we report the first observation of Rabi-like oscillations in a coupled SAW-spin wave system, revealing the dynamical formation of magnon-polarons in the time domain. These results establish a platform for engineering hybrid spin-acoustic excitations in extended magnetic systems and enable time-resolved studies of magnon-polaron states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Hidden degree of freedom implied by unusual nonlocal transport in a topological semimetal
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Yongjian Wang, A. A. Taskin, Yoichi Ando
The spin Hall and inverse spin Hall effects have established a principle to understand nonlocal charge transport due to an additional degree of freedom. This principle applies successfully to the nonlocal transport due to the valley degree of freedom in graphene or to the chiral degree of freedom in a Weyl semimetal. Here we report the discovery of an unusual nonlocal charge transport that cannot be explained by any known mechanism and hence points to the existence of a hidden degree of freedom. This phenomenon was found in ZrTe$ _5$ in the nodal-line semimetal phase and it occurs in the ultraquantun limit driven by the magnetic field applied along the $ a$ -axis. Surprisingly, the decay length of the nonlocality increases linearly with the sample width and exceeds 100 $ \mu$ m, suggesting that the relevant degree of freedom experiences little scattering. This nonlocal transport shows up not only as a longitudinal voltage gradient, but also as an unusual nonlocal Hall effect. Such an exotic phenomenon in a topological material is unprecedented and implies new physics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
19 pages total; 6 pages of main text with 4 figures, 13 pages of supplement with 15 figures. The raw data and codes are available at the online depository Zenodo with the identifier https://doi.org/10.5281/zenodo.15330418
The Stress-Force-Fabric relation across shear bands
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
Carmen Lee, Émilien Azéma, Karen Daniels
The strength of granular materials is highly dependent on grain connectivity (fabric), force transmission, and frictional mobilization at the particle scale. Furthermore, these bulk properties are strongly dependent on the geometry and history of loading. It is well established that anisotropy in fabric and force transmission through a granular packing directly relates to the bulk scale strength of the packing via the Stress-Force-Fabric (SFF) relation. We have recently verified the validity of this framework for a broad variety of loading histories and geometries in experimental granular packings, using photoelastic disks to measure individual interparticle contact forces. By tracking both particle positions and interparticle contact force vectors, we mapped the anisotropy of the fabric and forces to the macroscale stress and strain and found excellent agreement between the anisotropic particle-scale measures and the macroscale responses in experiments. Here, we present an analysis of the effect of strong spatial gradients (shear bands) using the SFF framework in a sheared annular geometry, finding that there are strong variations in contact orientation depending on the location within or outside the shear band, even though the principal loading direction is uniform. This highlights that the fabric connectivity significantly changes across the shear band but does not contribute to the direct loading of the material. We disentangle the effects of packing fraction gradients and boundary constraints on the differences in fabric orientation.
Soft Condensed Matter (cond-mat.soft)
4 pages, 3 figures
A consistent description of the kinetic processes of electrolyte ion transport in a dynamic porous medium
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-12 20:00 EDT
P. P. Kostrobij, B. M. Markovych, O. V. Viznovych, M. V. Tokarchuk
The consistent description of kinetic and hydrodynamic processes is applied to the study of ion transport processes in the ionic solution-porous medium system. A system of equations is obtained for the nonequilibrium single-ion distribution function, the nonequilibrium average value of the energy density of the interaction of solution ions, and the nonequilibrium average value of the number density of particles in a porous medium. Using the fractional calculus technique, a generalized diffusion equation of the Cattaneo type in fractional derivatives is obtained to describe the processes of subdiffusion of particles in a porous medium.
Statistical Mechanics (cond-mat.stat-mech)
15 pages
Generic Chiral Anomaly and Planar Hall Effect in a Non-Weyl System
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Yongjian Wang, Alexander Wowchik, Thomas Boemerich, A. A. Taskin, Achim Rosch, Yoichi Ando
The condensed-matter version of the chiral anomaly describes how electrons are pumped from a Weyl node with negative chirality to a Weyl node with positive chirality using parallel electric and magnetic fields. Key experimental signatures are a negative longitudinal magnetoresistance (LMR) and the planar Hall effect (PHE), both of which have been experimentally observed. Here, we show that the chiral anomaly explains key features of magnetotransport in the nodal-line semimetal ZrTe$ _5$ despite the absence of Weyl points. The anomaly physics applies generically to materials in the quantum limit, when electron transport becomes quasi-one-dimensional, provided that Fermi velocities remain sufficiently large. This explains not only the negative LMR but also the PHE with a gigantic Hall angle and a highly unusual magnetic-field-angle dependence in ZrTe$ _5$ .
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
17 pages total; 8 pages of main text with 5 figures, 9 pages of supplement with 6 figures. The raw data are available at the online depository Zenodo with the identifier https://doi.org/10.5281/zenodo.15634664
Elastic properties of fluid mercury across the metal-nonmetal transition: Ab initio simulation study
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-12 20:00 EDT
T. Bryk, O. Bakai, A. P. Seitsonen
We report an ab initio molecular dynamics study of fluid mercury at temperature 1750 K in the range of densities 7-13.5 g/cm$ ^3$ . Along this isothermal line we performed an analysis of total charge fluctuations, which make evidence of neutral atom-like screening in fluid Hg for densities less than 9.25 g/cm$ ^3$ , which practically coincides with the emergence of the gap in electronic density of states. High-frequency shear modulus, high-frequency and adiabatic speeds of sound, shear viscosity, Maxwell relaxation time and dispersion of collective excitations are analyzed as a function of density along the isothermal line.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
12 pages, 9 figures
Single Cu Atom Sites on Co3O4 Activate Interfacial Oxygen for Enhanced Reactivity and Selective Gas Sensing at Low Temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Hamin Shin, Matteo D’Andria, Jaehyun Ko, Dong-Ha Kim, Frank Krumeich, Andreas T. Guentner
Controlling the redox landscape of transition metal oxides is central to advancing their reactivity for heterogeneous catalysis or high-performance gas sensing. Here we report single Cu atom sites (1.42 wt%) anchored on Co3O4 nanoparticles (Cu1-Co3O4) that dramatically enhance reactivity and molecular sensing properties of the support at low temperature. The Cu1 are identified by X-ray adsorption near edge structure and feature strong metal-support interaction between Cu2+ and Co3O4, as revealed by X-ray photoelectron spectroscopy. The ability of Cu1 to form interfacial Cu-O-Co linkages strongly reduces the temperature of lattice oxygen activation compared to CuO nanoparticles on Co3O4 (CuONP-Co3O4), as demonstrated by temperature-programmed reduction and desorption analyses. To demonstrate immediate practical impact, we deploy such Cu1-Co3O4 nanoparticles as chemoresistive sensor for formaldehyde vapor that yields more than an order of magnitude higher response than CuONP-Co3O4 and consistently outperforms state-of-the-art sensors. That way, formaldehyde is detected down to 5 parts-per-billion at 50% relative humidity and 75 °C with excellent selectivity over various critical interferents. These results establish a mechanistic platform for activating redox-active supports using single-atom isolates of non-noble nature that yield drastically enhanced and well-defined reactivity to promote low-temperature oxidation reactions and selective analyte sensing.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph)
Probing anyon statistics on a single-edge loop in the fractional quantum Hall regime
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Flavio Ronetti, Noé Demazure, Jérôme Rech, Thibaut Jonckheere, Benoît Grémaud, Laurent Raymond, Masayuki Hashisaka, Takeo Kato, Thierry Martin
We propose a setup to directly measure the anyonic statistical angle on a single edge of a fractional quantum Hall system, without requiring independent knowledge of non-universal parameters. We consider a Laughlin edge state bent into a closed loop geometry, where tunneling processes are controllably induced between the endpoints of the loop. To illustrate the underlying physical mechanism, we compute the time-dependent current generated by the injection of multiple anyons, and show that its behavior exhibits distinctive features governed by the anyonic statistical angle. The measured current reflects quantum interference effects due to the time-resolved braiding of anyons at the junction. To establish experimental relevance, we introduce a protocol where anyons are probabilistically injected upstream of the loop via a quantum point contact (QPC) source. Unlike in Fabry-Perot interferometers, where phase jumps occur spontaneously due to stochastic quasi-particle motion, here the phase jumps are deliberately induced by source injections. These events imprint measurable signatures in the cross-correlation noise, enabling a controlled statistical analysis of the braiding phase. We further show that, by varying the magnetic field while remaining within the same fractional quantum Hall plateau, the statistical angle can be extracted without relying on the knowledge of other non-universal system parameters. Our results provide a minimal and accessible platform for probing anyonic statistics using a single chiral edge.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
18 pages, 8 figures, joint PRB/PRL submission with arXiv:2503.17008, comments are welcome !
Two-site entanglement in the two-dimensional Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Frederic Bippus, Anna Kauch, Gergő Roósz, Christian Mayrhofer, Fakher Assaad, Karsten Held
The study of entanglement in strongly correlated electron systems typically requires knowledge of the reduced density matrix. Here, we apply the parquet dynamical vertex approximation to study the two-site reduced density matrix at varying distance, in the Hubbard model at weak coupling. This allows us to investigate the spatial structure of entanglement in dependence of interaction strength, electron filling, and temperature. We compare results from different entanglement measures, and benchmark against quantum Monte Carlo.
Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 11 figures
Photo-induced directional transport in extended SSH chains
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Usham Harish Kumar Singha, Kallol Mondal, Sudin Ganguly, Santanu K. Maiti
We investigate the current-voltage characteristics of an extended Su-Schrieffer-Heeger (SSH) chain under irradiation by arbitrarily polarized light, demonstrating its potential as a light-controlled rectifier. Irradiation of light induces anisotropy in the system, enabling directional current flow and active control of rectification behavior. Our analysis demonstrates that, under optimized light parameters, the rectification efficiency can exceed 90%. Moreover, the direction of rectification-whether positive or negative-can be precisely controlled by varying the polarization of the light, highlighting the potential for external optical control of electronic behavior. The effect of light irradiation is incorporated using the Floquet-Bloch ansatz combined with the minimal coupling scheme, while charge transport is computed through the nonequilibrium Green’s function formalism within the Landauer-Büttiker framework.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
7 pages, 6 figures. Comments are welcome
Influence of photon-magnon coupling to enhance spin-wave excitation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Liubov Ivzhenko, Sergey Polevoy, Sergey Nedukh, Maciej Krawczyk
One of the main challenges in magnonics is the efficiency of the conversion of microwave signals into spin waves. This efficiency is low due to the significant mismatch between microwave and spin wave wavelengths in the GHz range $ 10^{-2}$ m and $ 10^{-8}$ m, respectively, leading to high energy consumption in magnonic circuits. To address this issue, we propose an approach based on a planar inverse split-ring resonator (ISRR) loaded with a nanometer-thick Py film and exploiting the photon-magnon coupling effect. Our numerical studies show that the ISRR-based antenna achieves more than a fourfold improvement in conversion efficiency compared to a conventional single microstrip transmission line at frequencies and bias magnetic fields around the anti-crossing frequency gap. This has been demonstrated in the weak photon-magnon coupling regime for the nanometer-thin permalloy film with micrometer lateral dimensions. Further optimization of the ISRR can help to achieve the strong coupling regime, making the system potentially useful for quantum technology. Our compact and efficient antenna design offers a significant advantage over standard microstrip lines, paving the way for scalable and powerful magnonic circuits for microwave signal processing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Surface Induced Frustration of Inherent Dipolar Order in Nanoconfined Water
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
Sayantan Mondal, Saumyak Mukherjee, Biman Bagchi
Surface effects could play a dominant role in modifying the natural liquid order. In some cases, the effects of the surface interactions can propagate inwards, and even can interfere with a similar propagation from opposite surfaces. This can be particularly evident in liquid water under nano-confinement. The large dipolar cross-correlations among distinct molecules that give rise to the unusually large dielectric constant of water (and in turn owe their origin to the extended hydrogen bond (HB) network) can get perturbed by surfaces. The perturbation can propagate inwards and then interfere with the one from the opposite surface if confinement is only a few layers wide. This can give rise to short-to-intermediate range solvent-mediated interaction between two surfaces. Here we study the effects of such interactions on the dielectric constant of nano-confined liquids, not just water but also ordering at protein surfaces. The surfaces work at two levels: (i) induce orientational realignment, and (ii) alter the cross-correlations between water molecules. Molecular dynamics simulations and statistical analyses are used to address these aspects in confinement of slit pores, nano tube/cylinder, and nano sphere. In addition, we consider the hydration layers of multiple proteins with vastly different structural features. These studies give us a measure of the extent or the length scale of cross-correlations between dipole moments of water molecules. We find an interesting orientational arrangement in the protein hydration layers, giving rise to long-range molecular cross-correlations. To decouple the effect of HB from the effect of geometry, we additionally study acetonitrile under nanoconfinement. Importantly, while a protein’s interior is characterized by a small dielectric constant, the dipole moment of a peptide bond is large, and thus susceptible to fluctuations in water.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech), Biomolecules (q-bio.BM)
24 pages, 8 figures, 3 tables
Fermi surface and effective masses of IrO$_2$ probed by de Haas-van Alphen quantum oscillations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Kathrin Götze, Matthew J. Pearce, Suchit Negi, Jian-Rui Soh, Dharmalingam Prabhakaran, Paul A. Goddard
Iridium-containing conducting materials are widely investigated for their strong spin-orbit coupling and potential topological properties. Recently the commonly used electrode material iridium dioxide was found to host a large spin-Hall conductivity and was shown to support Dirac nodal lines. Here we present quantum-oscillation experiments on high-quality IrO$ _2$ single crystals using the de Haas-van Alphen effect measured using torque magnetometry with a piezo-resistive microcantilever as well as density functional theory-based band-structure calculations. The angle, temperature and field dependencies of the oscillations and the calculated band dispersion provide valuable information on the properties of the charge carriers, including the Fermi-surface geometry and electronic correlations. Comparison of experimental results to calculations allows us to assigns the observed de Haas-van Alphen frequencies to the calculated Fermi surface topology. We find that the effective masses of IrO$ _2$ are enhanced compared to the rest electron mass $ m_e$ , ranging from 1.9 to 3.0~$ m_e$ , whereas the scattering times indicate excellent sample quality. We discuss our results in context with recent ARPES and band-structure calculation results that found Dirac nodal lines in IrO$ _2$ and compare the effective masses and other electronic properties to those of similar materials like the nodal chain metal ReO$ _2$ in which Dirac electrons with very light effective masses have been observed.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
7 pages, 5 figures
Anomalous slow-down of the bound state dynamics in a non-locally coupled quantum circuit
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-06-12 20:00 EDT
Biswajit Paul, Suman Mondal, Tapan Mishra
Additional hopping channels in a tight-binding lattice is known to introduce faster dynamics of a quantum mechanical particle. However, we show that in the case of a repulsively bound state, the dynamics becomes abnormally slow when next-nearest neighbor (NNN) hopping is allowed for the particles. We show that such slowing down occurs for some magic strength of the NNN hopping at which the bound state band exhibits a quasi-flatband feature. We reveal this anomalous dynamical behavior by analyzing the quench dynamics of two nearest neighbor (NN) spin excitations (magnons) on a ferromagnetic chain by allowing both NN and NNN couplings. By implementing digital quantum computing simulations on a NISQ device, we obtain such non-trivial signatures and complement the results with exact numerical calculations. Moreover, through perturbative arguments, we reveal that the slowing down is due to the destructive interference between different paths associated to the bound state dynamics.
Quantum Gases (cond-mat.quant-gas), Other Condensed Matter (cond-mat.other), Quantum Physics (quant-ph)
4+5 pages, 5+4 figs
Coexistence of static and dynamic local magnetic fields in an S = 3/2 honeycomb lattice antiferromagnet Co2Te3O8
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
J. Khatua, Suheon Lee, M. Pregelj, Samiul Sk, S. K. Panda, Bassam Hitti, Gerald D. Morris, I. da Silva, Kwang-Yong Choi, P. Khuntia
Two-dimensional honeycomb lattices, characterized by their low coordination numbers, provide a fertile platform for exploring various quantum phenomena due to the intricate interplay between competing magnetic interactions, spin-orbit coupling, and crystal electric fields. Beyond the widely studied Jeff= 1/2 honeycomb systems, S = 3/2 honeycomb lattices present a promising alternative route to realizing the classical spin liquid-like state within the spin-S Kitaev models. Herein, we present crystal structure, thermodynamic, neutron diffraction and muon spin relaxation (muSR) measurements, complemented by density functional theory (DFT) calculations on an unexplored 3d transition metal based compound Co2Te3O8, where Co2+ (S = 3/2) ions form a distorted honeycomb lattice in the crystallographic bc-plane without any anti-side disorder between constituent atoms. A clear lambda type anomaly around 55 K in both magnetic susceptibility and specific heat data indicates the onset of a long-range ordered state below TN= 55 K. The dominant antiferromagnetic interaction between S = 3/2 moments is evidenced by a relatively large negative Curie-Weiss temperature of -103 K derived from magnetic susceptibility data and supported by DFT calculations. The signature of long-range antiferomagnetic order state in the thermodynamic data is corroborated by neutron diffraction and muSR results. Furthermore, muSR experiments reveal the coexistence of static and dynamic local magnetic fields below TN, along with a complex magnetic structure that can be associated with XY-like antiferromagnet, as confirmed by neutron diffraction experiments.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Surface phase behavior, not hydrogen bonding, governs hydrophobic attraction between extended solutes
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-06-12 20:00 EDT
Nigel B. Wilding, Francesco Turci
Hydrophobic interactions are central to biological self-assembly and soft matter organization, yet their microscopic origins remain debated. Traditional explanations often attribute the increase in attraction between hydrophobic solutes with increasing temperature to entropy changes resulting from disrupted hydrogen bonding in water. Here, we present a different perspective based on the physics of surface phase transitions, supported by extensive molecular dynamics simulations. Using well-tempered metadynamics, we quantify the solvent-mediated potential of mean force between nanometer-scale hydrophobic solutes in the monatomic water model (mW), the SPC/E water model, and a Lennard-Jones solvent. We develop a morphometric model grounded in a scaling theory of critical drying, linking the range and strength of hydrophobic attraction to interfacial thermodynamics and deviations from vapor-liquid coexistence, rather than specific hydrogen-bonding effects. Our results reproduce the characteristic inverse temperature dependence of hydrophobicity and demonstrate that such behavior arises generically due to a rapid thermal expansion of the solvation shell, independent of hydrogen bonding. This work reframes hydrophobic interactions between extended solutes as a universal solvophobic phenomenon governed by surface phase behavior.
Soft Condensed Matter (cond-mat.soft)
22 pages, 16 figures
Magnetic excitations and exchange parameters of a nickel chain compound PbMn$_2$Ni$_6$Te$3$O${18}$: Neutron scattering and density functional theory studies
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
S. Uthayakumar, D. T. Adroja, Amit Pokhriyal, A. K. Bera, Haranath Ghosh, Tatiana Gudi, Manh Duc Le, Christian Balz, R. A. Ewings, Minal Gupta, P. R. Sagdeo, D. Prabhakaran, J.P. Goff
We have investigated the quasi-one dimensional Ni-chain compound PbMn$ _2$ Ni$ _6$ Te$ _2$ O$ _{18}$ using theoretical DFT calculations, inelastic neutron scattering and optical spectroscopy in order to understand the nature of magnetic exchange interactions. Our inelastic neutron scattering study at 5 K on a powder sample reveals two bands of magnetic excitations, the first near 8 meV and the second near 18 meV originating from the antiferromagnetic zone center near $ Q$ = 1~Å. On the other hand at 100 K (which is above T$ _N$ = 86 K) a broad diffuse scattering signal is observed indicating the presence of short range magnetic correlations. We have analyzed the magnetic excitations based on the Linear Spin Wave Theory (LSWT) and compared the experimentally estimated exchange parameters with the DFT calculations. Our analysis reveals that the value of the exchange parameter at the larger distance (d=3.654 $ Å$ ) $ J_3$ =4.21(8) meV between Ni-Ni (from inter-chain) is the strongest amongst the allowed six exchange parameters, which suggests that this system is not really a quasi-one-dimensional and confirmed by the absence of a Haldane gap. We have also presented the electronic structure calculations. The spin-polarized partial density of states (DOS) projected onto the Mn-d and Ni-d orbitals reveals that the Ni-d$ _{x^2-y^2}$ contribution is dominant below the Fermi level in the spin-up and spin-down channel, while a minimal contribution from spin-up Mn states in the occupied region, suggesting a nearly high-spin state. The estimated Néel temperature, based on experimental exchange parameters is found to be in close agreement with the experimental value.
Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 13 figures
Physical Review B 111, 184432 (2025)
Unusual electron correlations in Kagome metals $AV_3Sb_5$ (A= K, Rb, Cs)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
Feihu Liu, Changxu Liu, Maolin Zeng, Qiyi Zhao
The investigation of electronic order-quantum phase interplay in Kagome lattices commonly employs the extended Kagome-Hubbard model, where the critical parameters comprise on-site $ (U)$ and intersite $ (V)$ Coulomb interactions. In prototypical kagome metals $ AV_3Sb_5$ (A = K, Rb, Cs), the geometrically frustrated quasi-2D architecture induces pressure-dependent complexity in vanadium d-electron correlations, necessitating systematic theoretical scrutiny. Utilizing the $ d-dp$ model within constrained random phase approximation (cRPA), we quantified $ U$ , $ V$ , and Hund’s coupling $ J$ under hydrostatic pressure (0-9 GPa). While $ KV_3Sb_5$ and $ RbV_3Sb_5$ exhibit pressure-insensitive interaction parameters, $ CsV_3Sb_5$ manifests anomalous discontinuities in $ U$ and $ V$ near $ 0.2$ GPa, suggesting a first-order electronic phase transition. This work establishes cRPA-derived interaction landscapes as critical predictors for pressure-tunable quantum phenomena in correlated kagome systems, offers a new insight into the understanding of the interplay between the CDW transition and the double superconductivity dome in $ CsV_3Sb_5$ at low pressure.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
8 pages, 6 figures
Sequential Dynamics in Ising Spin Glasses
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-06-12 20:00 EDT
Yatin Dandi, David Gamarnik, Francisco Pernice, Lenka Zdeborová
We present the first exact asymptotic characterization of sequential dynamics for a broad class of local update algorithms on the Sherrington-Kirkpatrick (SK) model with Ising spins. Focusing on dynamics implemented via systematic scan – encompassing Glauber updates at any temperature – we analyze the regime where the number of spin updates scales linearly with system size. Our main result provides a description of the spin-field trajectories as the unique solution to a system of integro-difference equations derived via Dynamical Mean Field Theory (DMFT) applied to a novel block approximation. This framework captures the time evolution of macroscopic observables such as energy and overlap, and is numerically tractable. Our equations serve as a discrete-spin sequential-update analogue of the celebrated Cugliandolo-Kurchan equations for spherical spin glasses, resolving a long-standing gap in the theory of Ising spin glass dynamics. Beyond their intrinsic theoretical interest, our results establish a foundation for analyzing a wide variety of asynchronous dynamics on the hypercube and offer new avenues for studying algorithmic limitations of local heuristics in disordered systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Mathematical Physics (math-ph)
55 pages, 6 figures
Microscopic investigation of enhanced Pauli paramagnetism in metallic Pu$_2$C$_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-06-12 20:00 EDT
R. Yamamoto, M. S. Cook, A. R. Altenhof, P. Sherpa, S. Park, J. D. Thompson, H. E. Mason, D. C. Arellano, D. V. Prada, P. H. Tobash, F. Ronning, E. D. Bauer, N. Harrison, W. A. Phelan, A. P. Dioguardi, M. Hirata
A combined study of the structural and electronic properties of polycrystalline Pu$ _2$ C$ _3$ is reported based on x-ray diffraction, specific heat, magnetic susceptibility, $ {}^{13}$ C nuclear magnetic resonance (NMR), and band structure calculations. X-ray diffraction reveals a global noncentrosymmetric cubic lattice, with a nearest-neighbor C–C bond length of $ r = 1.38$ Å. $ {}^{13}$ C NMR measurements indicate that the global cubic symmetry is locally broken, revealing two unique carbon environments. Magnetic susceptibility suggests enhanced Pauli paramagnetism, and specific heat reveals a moderately large electronic Sommerfeld coefficient $ \gamma = 45$ mJ mol$ _{\mathrm{Pu}}^{-1}$ K$ ^{-2}$ , with a Wilson ratio $ R_W \approx 1.3$ further indicating moderate correlations. $ {}^{13}$ C nuclear spin-lattice relaxation rate ($ 1/T_1$ ) and Knight shift ($ K$ ) measurements find metallic Korringa behavior (i.e., $ T_1TK^2=$ const.) with modest ferromagnetic spin fluctuations at low temperature. Taken together, the data point to a delocalized nature of a narrow 5$ f$ -electron band with weak electronic correlations. Density functional theory band-structure calculations confirm the appearance of such narrow 5$ f$ bands near the Fermi level. Our data provide prime evidence for a plutonium-based metallic system with weak electronic correlations, which sheds new light on the understanding of complex paramagnetism in actinide-based metallic compounds.
Strongly Correlated Electrons (cond-mat.str-el)
Discrete-space and -time analogue of a super-diffusive fractional Brownian motion
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-06-12 20:00 EDT
We discuss how to construct reliably well “a lattice and an integer time” version of a super-diffusive continuous-space and -time fractional Brownian motion (fBm) – an experimentally-relevant non-Markovian Gaussian stochastic process with an everlasting power-law memory on the time-evolution of thermal noises extending over the entire past. We propose two algorithms, which are both validated by extensive numerical simulations showing that the ensuing lattice random walks have not only the same power-law covariance function as the standard fBm, but also individual trajectories follow those of the super-diffusive fBm. Finding a lattice and an integer time analogue of a sub-diffusion fBm, which is an anti-persistent process, remains a challenging open problem. Our results also clarify the relevant difference between sub-diffusive and super-diffusive fBm, that are frequently seen as two very analogous realizations of processes with memory. They are indeed substantially different.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Biological Physics (physics.bio-ph), Biomolecules (q-bio.BM)
accepted for publication on Chaos
Emergent anisotropic three-phase order in critically doped superconducting diamond films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-06-12 20:00 EDT
Jyotirmay Dwivedi, Jake Morris, Saurav Islam, Kalana D. Halanayake, Gabriel A. Vazquez-Lizardi, David Snyder, Anthony Richardella, Luke Lyle, Danielle Reifsnyder Hickey, Nazar Delegan, F. Joseph Heremans, David D. Awschalom, Nitin Samarth
Two decades since its discovery, superconducting heavily boron-doped diamond (HBDD) still presents unresolved fundamental questions whose resolution is relevant to the development of this material for quantum technologies. We use electrical magnetotransport measurements of critically-doped homoepitaxial single crystal HBDD films to reveal signatures of intrinsic (electronic) granular superconductivity. By studying the dependence of electrical resistivity on temperature and magnetic field vector, we infer that this granularity arises from electron correlations. This is revealed by a striking three-phase anisotropy in the magnetoresistance, accompanied by a spontaneous transverse voltage (Hall anomaly). Our findings indicate an emergent magnetically tunable intrinsic order in an otherwise isotropic three dimensional single crystal HBDD film, offering new insights into the mechanism of superconductivity in this quantum material.
Superconductivity (cond-mat.supr-con)
Optical spin pumping in silicon
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-06-12 20:00 EDT
Stefano Achilli, Damiano Marian, Mario Lodari, Emiliano Bonera, Giordano Scappucci, Jacopo Pedrini, Michele Virgilio, Fabio Pezzoli
The generation of an out-of-equilibrium population of spin-polarized carriers is a keystone process for quantum technologies and spintronics alike. It can be achieved through the so-called optical spin orientation by exciting the material with circularly polarized light. Although this is an established technique for studying direct band-gap semiconductors, it has been proven limited in materials like Si that possess weak oscillator strengths for the optical transitions. In this study, we address the problem by presenting an all-optical analog of the spin pumping method. This involves the optical creation of a non-equilibrium spin population within an absorber, which subsequently transfers spin-polarized carriers to a nearby indirect gap semiconductor, resulting in polarized emission from the latter. By applying this concept to a Ge-on-Si heterostructure we observe luminescence from Si with an unrivaled polarization degree as high as 9%. The progressive etching of the absorbing layer, assisted by magneto-optic experiments, allows us to ascertain that the polarized emission is determined by effective spin injection aided by the carrier lifetime shortening due to extended defects. These findings can facilitate the use of highly promising spin-dependent phenomena of Si, whose optical exploitation has thus far been hampered by fundamental limitations associated with its peculiar electronic structure.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Designing Corrosion-Resistant CoCrNi Medium Entropy Alloys via Short-Range Order Modification
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Elaf A. Anber, Debashish Sur, Annie K. Barnett, Daniel L. Foley, Andrew M. Minor, Brian L. DeCost, Howie Joress, Anatoly I. Frenkel, Michael L. Falk, John R. Scully, Mitra L. Taheri
Equiatomic CoCrNi medium entropy alloys are known for their unique properties linked to chemical short-range order (CSRO), crucial in both percolation processes and/or nucleation and growth processes influencing alloy passivation in aqueous environments. This study combines extended x-ray absorption fine structure, atomistic simulations, electrochemical methods, x-ray photoelectron spectroscopy, and transmission electron microscopy to explore CSRO evolution, passive film formation, as well as its characteristics in the as-homogenized CoCrNi condition, both before and after aging treatment. Results reveal a shift in local alloying element bonding environments post-aging, with simulations indicating increased Cr-Cr CSRO in 2nd nearest neighbor shells. Enhanced passive film formation kinetics and superior protection of the aged alloy in harsh acidified 3 mol/L NaCl solution indicate improved aqueous passivation correlated with Cr-Cr CSRO. This work establishes a direct connection between alloy CSRO and aqueous passivation in CoCrNi, highlighting its potential for tailored corrosion-resistant applications.
Materials Science (cond-mat.mtrl-sci)
Evidence for Bose liquid from anomalous shot noise in nanojunctions of bad metal beta-Ta
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-06-12 20:00 EDT
Yiou Zhang, Chendi Xie, John Bacsa, Yao Wang, Sergei Urazhdin
We report anomalous shot noise in nanojunctions of beta-tantalum, a ``bad” metal whose electronic properties are inconsistent with the Fermi liquid theory. Fano factors cluster around even multiples of the values expected for Fermi liquids, suggesting that beta-Ta may host a correlated charge liquid of Cooper pair-like electron groups. Further evidence for correlations is provided by the effects of magnetic impurities, as well as reduced density of states near the Fermi level indicated by point contact spectroscopy and first principles calculations. Our results open new avenues for studies and applications of electron correlations.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
comments are welcome