CMP Journal 2025-05-01
Statistics
Nature Nanotechnology: 1
Nature Physics: 4
Nature Reviews Materials: 1
Physical Review Letters: 19
Physical Review X: 2
Review of Modern Physics: 1
arXiv: 54
Nature Nanotechnology
Operando X-ray characterization platform to unravel catalyst degradation under accelerated stress testing in CO2 electrolysis
Original Paper | Electrocatalysis | 2025-04-30 20:00 EDT
Qiucheng Xu, José A. Zamora Zeledón, Bjørt Óladóttir Joensen, Lena Trotochaud, Andrea Sartori, Lau Morten Kaas, Asger Backholt Moss, Marta Mirolo, Luis Mairena, Sylvia Huynh, Sahil Garg, Stig Helveg, Ib Chorkendorff, Shuai Zhao, Brian Seger, Jakub Drnec
Membrane-electrode assembly (MEA)-based CO2 electrolysis shows great potential for industrial-scale chemical production, but long-term stability remains a key challenge. The degradation mechanisms of catalysts and electrodes in MEAs are not yet fully understood. Here a customized operando synchrotron X-ray characterization platform was established to track the time- and space-resolved evolution of ions and water movement, crystal structure and catalyst variations in MEAs. Using Au and Ag model catalysts, we show that the crystalline phase catalyst stability and catalyst-substrate adhesion are critical to MEA durability. Small- and wide-angle X-ray scattering analysis reveals that Au catalysts, with their robust crystal structure and stable catalyst-substrate adhesion, maintain stability under accelerated stress tests, whereas Ag catalysts degrade due to particle agglomeration, an undesirable dissolution-recrystallization process and detachment. This study demonstrates the advanced capabilities of operando X-ray techniques in elucidating catalyst and electrode degradation in CO2 electrolysers.
Electrocatalysis, Nanoparticles
Nature Physics
Observation of Floquet-Bloch states in monolayer graphene
Original Paper | Electronic properties and materials | 2025-04-30 20:00 EDT
Dongsung Choi, Masataka Mogi, Umberto De Giovannini, Doron Azoury, Baiqing Lv, Yifan Su, Hannes Hübener, Angel Rubio, Nuh Gedik
Floquet engineering enables the manipulation of quantum phases of matter through periodic driving. It has been implemented across different platforms, ranging from photonic systems to optical lattices of ultracold atoms. In solids, coherent light-matter interaction induced by periodic driving leads to hybridization of Bloch electrons with photons, resulting in the formation of replica bands known as Floquet-Bloch states. These states have been observed in several materials, and their properties have been linked to a range of predicted phase transitions. However, direct energy and momentum-resolved observation of these states remains limited to a few. Here we report the direct observation of Floquet-Bloch states in monolayer epitaxial graphene. By using time-resolved and angle-resolved photoemission spectroscopy with mid-infrared pump excitation, we detected replicas of the Dirac cone. The dependence of these replica bands on pump polarization shows that they originate from the scattering between Floquet-Bloch states and photon-dressed free-electron-like photoemission final states, known as Volkov states. Our method can potentially be used to directly observe Floquet-Bloch states at large momenta in other quantum materials.
Electronic properties and materials
Microscopic signatures of topology in twisted MoTe2
Original Paper | Electronic properties and materials | 2025-04-30 20:00 EDT
Ellis Thompson, Keng Tou Chu, Florie Mesple, Xiao-Wei Zhang, Chaowei Hu, Yuzhou Zhao, Heonjoon Park, Jiaqi Cai, Eric Anderson, Kenji Watanabe, Takashi Taniguchi, Jihui Yang, Jiun-Haw Chu, Xiaodong Xu, Ting Cao, Di Xiao, Matthew Yankowitz
In moiré materials with flat electronic bands and suitable quantum geometry, strong correlations can give rise to various topological states of matter. The non-trivial band topology of twisted MoTe2, which is responsible for its fractional quantum anomalous Hall states, is predicted to arise from a skyrmion lattice texture in the layer pseudospin of the electronic wavefunctions. Tracing the layer polarization of wavefunctions within the moiré unit cell can, thus, offer insights into the band topology. Here we measure the out-of-plane component of the layer-pseudospin skyrmion textures of twisted MoTe2 using scanning tunnelling microscopy and spectroscopy. We do this by simultaneously visualizing the moiré lattice structure and the spatial localization of its electronic states. We find that the wavefunctions associated with the topological flat bands exhibit a spatially dependent layer polarization within the moiré unit cell, in agreement with our theoretical modelling. Our work enables future local probe studies of the intertwined correlated and topological states arising in gate-tunable devices.
Electronic properties and materials, Topological insulators, Two-dimensional materials
Collective quench dynamics of active photonic lattices in synthetic dimensions
Original Paper | Nonlinear optics | 2025-04-30 20:00 EDT
Alexander Dikopoltsev, Ina Heckelmann, Mathieu Bertrand, Mattias Beck, Giacomo Scalari, Oded Zilberberg, Jérôme Faist
Photonic emulators have enabled the study of many solid-state and quantum optics phenomena, such as Anderson localization, topological insulators and non-Hermitian dynamics. Current photonic emulators are generally limited to bosonic behaviour with local interactions, but the use of synthetic dimensions offers a pathway to overcome this constraint. Here we investigate the flow of liquid light in modulated fast-gain ring lasers, and we establish a platform for emulating quench dynamics within a synthetic photonic lattice with equal densities across the reciprocal space. We apply an artificial electric field to the lattice and introduce a slow timescale to the flow, given by Bloch oscillations. Despite the dispersion and dissipation in our system, which desynchronize the Wannier-Stark ladder states, we were able to directly observe coherent oscillations facilitated by the fast gain. Additionally, we quenched a steady state of a coupled system onto an uncoupled one, which revealed coherent interactions between the decaying modes. These coherent dynamics resulted from the liquid state of light, which rapidly suppressed fluctuations at the shortest timescale of the system. This platform enriches our understanding of collective dynamics in the non-perturbative regime and improves our ability to control and generate coherent, multi-frequency sources.
Nonlinear optics, Ultrafast lasers
Experimental signature of layer skyrmions and implications for band topology in twisted WSe2 bilayers
Original Paper | Electronic properties and materials | 2025-04-30 20:00 EDT
Fan Zhang, Nicolás Morales-Durán, Yanxing Li, Wang Yao, Jung-Jung Su, Yu-Chuan Lin, Chengye Dong, Xiaohui Liu, Fu-Xiang Rikudo Chen, Hyunsue Kim, Kenji Watanabe, Takashi Taniguchi, Xiaoqin Li, Joshua A. Robinson, Allan H. Macdonald, Chih-Kang Shih
Twisted homobilayers of transition-metal dichalcogenides have been established as an ideal platform for studying strong correlation phenomena, as exemplified by the recent discovery of fractional Chern insulator states in twisted MoTe2, as well as Chern insulators and unconventional superconductivity in twisted WSe2. In these systems, a non-trivial topology in the strongly layer-hybridized regime can arise from a spatial patterning of interlayer tunnelling amplitudes and layer-dependent potentials that yields a lattice of layer skyrmions. Here we report experimental signatures of skyrmion textures in the layer degree of freedom of rhombohedral-stacked twisted WSe2 homobilayers. Using scanning tunnelling spectroscopy that separately resolves the Γ-valley and K-valley moiré electronic states, we reveal opposite layer polarizations of the K valley at two different lattice sites with opposite stacking order within the moiré unit cell. These findings are consistent with the theoretically predicted layer-skyrmion texture. We also use our experimental results to parameterize a common continuum model of moiré bands in twisted bilayers, further establishing a direct correlation between the shape of the local density of states in real space and the topology of the topmost moiré band.
Electronic properties and materials, Surfaces, interfaces and thin films, Two-dimensional materials
Nature Reviews Materials
Materials and device strategies to enhance spatiotemporal resolution in bioelectronics
Review Paper | Biomaterials | 2025-04-30 20:00 EDT
Jing Zhang, Zhe Cheng, Pengju Li, Bozhi Tian
Spatiotemporal resolution is a cornerstone of bioelectronics, enabling precise observation and control of biological events at the molecular, cellular and tissue levels. In this Review, we analyse recent advancements in spatiotemporal resolution essential for applications such as neuroprosthetics, cardiac monitoring and biosensing, with a focus on devices utilizing electrical, electrochemical and optoelectronic signal transduction. We define the intrinsic and extrinsic parameters of spatial and temporal resolution and highlight high-performance materials and device architectures – including electrodes, transistors and optoelectronic interfaces – that drive these capabilities. Strategies such as device miniaturization, 3D fabrication and multifunctional integration are evaluated for their capacity to improve resolution, particularly within the complex microenvironments of biological tissues. However, challenges persist, including signal interference, device stability and the demand for reliable long-term operation. Overcoming these obstacles requires continuous innovation in materials science, device engineering and computational approaches. Enhanced spatiotemporal resolution holds promise for advancing diagnostic precision, therapeutic responsiveness and our understanding of dynamic biological systems across biomedical disciplines.
Biomaterials, Electrophysiology, Materials for devices
Physical Review Letters
Variational LOCC-Assisted Quantum Circuits for Long-Range Entangled States
Research article | Quantum algorithms & computation | 2025-04-30 06:00 EDT
Yuxuan Yan, Muzhou Ma, You Zhou, and Xiongfeng Ma
Long-range entanglement is an important quantum resource, particularly for topological orders and quantum error correction. In reality, preparing long-range entangled states requires a deep unitary circuit, which poses significant experimental challenges. A promising avenue is offered by replacing some quantum resources with local operations and classical communication (LOCC). With these classical components, one can communicate outcomes of midcircuit measurements in distant subsystems, substantially reducing circuit depth in many important cases. However, to prepare general long-range entangled states, finding LOCC-assisted circuits of a short depth remains an open question. Here, to address this challenge, we propose a quantum-classical hybrid algorithm to find optimal LOCC protocols for preparing ground states of given Hamiltonians. In our algorithm, we introduce an efficient way to estimate parameter gradients and use such gradients for variational optimization. Theoretically, we establish the conditions for the absence of barren plateaus, ensuring trainability at a large system size. Numerically, the algorithm accurately solves the ground state of long-range entangled models, such as the perturbed Greenberger–Horne–Zeilinger state and surface code. Our results demonstrate the advantage of our method over conventional unitary variational circuits: the practical advantage in the accuracy of estimated ground-state energy and the theoretical advantage in creating long-range entanglement.
Phys. Rev. Lett. 134, 170601 (2025)
Quantum algorithms & computation, Quantum circuits, Quantum computation
Random Distillation Protocols in Long Baseline Telescopy
Research article | Entanglement manipulation | 2025-04-30 06:00 EDT
Yunkai Wang and Eric Chitambar
In quantum-enhanced astronomical imaging, multiple distant apertures work together by utilizing quantum resources distributed from a central server. Our findings suggest that preprocessing the stellar light received by all telescopes can improve imaging performance without increasing resource consumption. The preprocessing leverages weak quantum measurements and modifies random-party entanglement distillation protocols from quantum information science. Intuitively, this approach allows us to collapse the stellar light that is originally coherent between all telescopes to one pair of telescopes with probability arbitrarily close to one. The central server can then distribute entanglement solely to the pair of telescopes receiving a photon, thereby enhancing the efficiency of resource utilization. We discuss two types of resources that benefit from this preprocessing: shared entanglement and a shared reference frame.
Phys. Rev. Lett. 134, 170801 (2025)
Entanglement manipulation, Optical interferometry, Quantum metrology, Quantum networks, Quantum parameter estimation, Quantum sensing
First Axionlike Particle Results from a Broadband Search for Wavelike Dark Matter in the 44 to $52\text{ }\text{ }\mathrm{\mu }\mathrm{eV}$ Range with a Coaxial Dish Antenna
Research article | Dark matter direct detection | 2025-04-30 06:00 EDT
Gabe Hoshino, Stefan Knirck, Mohamed H. Awida, Gustavo I. Cancelo, Simon Corrodi, Martin Di Federico, Benjamin Knepper, Alex Lapuente, Mira Littmann, David W. Miller, Donald V. Mitchell, Derrick Rodriguez, Mark K. Ruschman, Chiara P. Salemi, Matthew A. Sawtell, Leandro Stefanazzi, Andrew Sonnenschein, Gary W. Teafoe, and Peter Winter (GigaBREAD Collaboration)
We present the results from the first axionlike particle search conducted using a dish antenna. The experiment was conducted at room temperature and sensitive to axionlike particles in the $44–52\text{ }\text{ }\mathrm{\mu }\mathrm{eV}$ range (10.7–12.5 GHz). The novel dish antenna geometry was proposed by the BREAD Collaboration and previously used to conduct a dark photon search in the same mass range. To allow for axionlike particle sensitivity, the BREAD dish antenna was placed in a 3.9 T solenoid magnet at Argonne National Laboratory. In the presence of a magnetic field, axionlike dark matter converts to photons at the conductive surface of the reflector. The signal is focused onto a custom coaxial horn antenna and read out with a low-noise radio-frequency receiver. No evidence of axionlike dark matter was observed in this mass range and we place the most stringent laboratory constraints on the axion-photon coupling strength, ${g}_{a\gamma \gamma }$, in this mass range at 90% confidence.
Phys. Rev. Lett. 134, 171002 (2025)
Dark matter direct detection, Particle astrophysics, Particle dark matter, Axion-like particles, Axions, Hypothetical particles, Dark matter detectors, Microwave techniques
Extended TeV Halos May Commonly Exist around Middle-Aged Pulsars
Research article | Cosmic rays & astroparticles | 2025-04-30 06:00 EDT
A. Albert et al.
*et al.*The results of a survey of middle-aged pulsars suggest that a feature previously seen around a handful of pulsars might be ubiquitous.
Phys. Rev. Lett. 134, 171005 (2025)
Cosmic rays & astroparticles, Gamma ray astronomy, Neutron stars & pulsars
Lattice QCD Study of Pion Electroproduction and Weak Production from a Nucleon
Research article | Electroweak interaction | 2025-04-30 06:00 EDT
Yu-Sheng Gao, Zhao-Long Zhang, Xu Feng, Lu-Chang Jin, Chuan Liu, and Ulf-G. Meißner
Quantum fluctuations in QCD influence nucleon structure and interactions, with pion production serving as a key probe of chiral dynamics. In this Letter, we present a lattice QCD calculation of multipole amplitudes at threshold, related to both pion electroproduction and weak production from a nucleon, using two gauge ensembles near the physical pion mass. We develop a technique for spin projection and construct multiple operators for analyzing the generalized eigenvalue problem in both the nucleon-pion system in the center-of-mass frame and the nucleon system with nonzero momentum. The numerical lattice results are then compared with those extracted from experimental data and predicted by low-energy theorems incorporating one-loop corrections.
Phys. Rev. Lett. 134, 171904 (2025)
Electroweak interaction, Lattice QCD, Pions
Nonperturbative Guiding Center Model for Magnetized Plasmas
Research article | Nuclear fusion | 2025-04-30 06:00 EDT
J. W. Burby, I. A. Maldonado, M. Ruth, D. A. Messenger, and L. Carbajal
Perturbative guiding center theory adequately describes the slow drift motion of charged particles in the strongly magnetized regime characteristic of thermal particle populations in various magnetic fusion devices. However, it breaks down for particles with large-enough energy. We report on a data-driven method for learning a nonperturbative guiding center model from full-orbit particle simulation data. We show the data-driven model significantly outperforms traditional asymptotic theory in magnetization regimes appropriate for fusion-born $\alpha $ particles in stellarators, thus opening the door to nonperturbative guiding center calculations.
Phys. Rev. Lett. 134, 175101 (2025)
Nuclear fusion, Magnetized plasma, First-principles calculations in plasma physics, Phase space dynamics
Isostructural Phase Transition of ${\mathrm{Fe}}{2}{\mathrm{O}}{3}$ under Laser Shock Compression
Research article | Dynamical phase transitions | 2025-04-30 06:00 EDT
A. Amouretti et al.
We present in situ x-ray diffraction and velocity measurements of ${\mathrm{Fe}}{2}{\mathrm{O}}{3}$ under laser shock compression at pressures between 38–122 GPa. None of the high-pressure phases reported by static compression studies were observed. Instead, we observed an isostructural phase transition from $\alpha \text{- }{\mathrm{Fe}}{2}{\mathrm{O}}{3}$ to a new ${\alpha }^{‘ }\text{- }{\mathrm{Fe}}{2}{\mathrm{O}}{3}$ phase at a pressure of 50–62 GPa. The ${\alpha }^{‘ }\text{- }{\mathrm{Fe}}{2}{\mathrm{O}}{3}$ phase differs from $\alpha \text{- }{\mathrm{Fe}}{2}{\mathrm{O}}{3}$ by an 11% volume drop and a different unit cell compressibility. We further observed a two-wave structure in the velocity profile, which can be related to an intermediate regime where both $\alpha $ and ${\alpha }^{‘ }$ phases coexist. Density functional theory calculations with a Hubbard parameter indicate that the observed unit cell volume drop can be associated with a spin transition following a magnetic collapse.
Phys. Rev. Lett. 134, 176102 (2025)
Dynamical phase transitions, Phase diagrams, Pressure effects, X-ray diffraction
Interplay between Interface Diffusion and Boundary Slip Underlying Graphite-Lubricated Metal Nanoforming
Research article | Creep | 2025-04-30 06:00 EDT
Jun-Xiang Xiang, Yuanpeng Yao, Hui Fang, Cai Lu, and Ze Liu
By designing carbon nanotube based nanochannels and exploiting the recent developed thermomechanical nanomolding technique, we reveal that the interface diffusion and boundary slip mechanisms play a key role in metal nanoforming. The former dominates the matter transport at the atomic scale and is significantly affected by surface defects, while the latter is closely related to the flow units at the continuum scale, and more sensitive to the apparent interfacial adhesion work than atomic scale defects. In particular, the excellent lubrication of graphitic materials maintained at high temperatures and in air is uncovered from the defect-insensitive boundary slip mechanism. Our findings not only clarify the fundamental physical processes behind metal nanoforming, but also provide new insights into nanofriction and lubrication.
Phys. Rev. Lett. 134, 176204 (2025)
Creep, Diffusion, Friction, Lubrication
Describing Landau Level Mixing in Fractional Quantum Hall States with Deep Learning
Research article | Electronic structure | 2025-04-30 06:00 EDT
Yubing Qian, Tongzhou Zhao, Jianxiao Zhang, Tao Xiang, Xiang Li, and Ji Chen
A novel framework using real-space neural networks simultaneously captures electron correlations and Landau level mixing with high precision.
Phys. Rev. Lett. 134, 176503 (2025)
Electronic structure, Fractional quantum Hall effect, Landau levels, Strongly correlated systems, Deep learning, Neural network simulations, Quantum Monte Carlo
Emergence of Ferroelectric Topological Insulator as Verified by Quantum Hall Effect of Surface States in (Sn,Pb,In)Te Films
Research article | Topological insulators | 2025-04-30 06:00 EDT
Ryutaro Yoshimi, Ryosuke Kurihara, Yoshihiro Okamura, Hikaru Handa, Naoki Ogawa, Minoru Kawamura, Atsushi Tsukazaki, Kei S. Takahashi, Masashi Kawasaki, Youtarou Takahashi, Masashi Tokunaga, and Yoshinori Tokura
Emergent phenomena arising from nontrivial band structures based on topology and symmetry have been attracting keen interest in contemporary condensed-matter physics. Materials such as SnTe and PbTe are one such example, which demonstrate a topological phase transition while showing ferroelectric instability derived from their rock-salt structure. The ferroelectricity can lift the valley degeneracy, enabling the emergence of the ${Z}_{2}$ topological insulator phase, although its observation in transport phenomena remains elusive. Here, we report magnetotransport properties of ferroelectric (Sn, Pb)Te thin films with finely controlled Fermi levels via In doping. We identified the ferroelectric topological insulator phase from the observations of the quantum Hall states with filling factors of $\nu =1$, 2, and 3 with both spin- and valley-degeneracy lifting. The electronic states are two-dimensional, indicating the ferroelectricity-induced topological surface states with a single Dirac cone. The finding of the new topological state with ferroelectricity will further expand the field of topological physics and advance the development of functional properties, such as topological nonlinear photonics and nonreciprocal transport with memory effect.
Phys. Rev. Lett. 134, 176602 (2025)
Topological insulators, Transport phenomena, Topological materials
Adiabatic Pumping of Orbital Magnetization by Spin Precession
Research article | Magnetism | 2025-04-30 06:00 EDT
Yafei Ren, Wenqin Chen, Chong Wang, Ting Cao, and Di Xiao
We propose adiabatic pumping of orbital magnetization driven by coherent spin precession, which enables rectification by converting periodic oscillations into a static signal. The orbital magnetization originates from the adiabatic evolution of valence electrons with a topological bulk contribution expressed as a Chern-Simons form. When the precession cone angle of spin $\mathbit{S}$ is small, the resulting magnetization is proportional to $\mathbit{S}\times{}\stackrel{ \dot{}{}}{\mathbit{S}}$ and contributes to the magnon Zeeman effect, the energy shift induced by a magnetic field. With a large cone angle, the magnetization can reach its natural unit, $e/T$, in an antiferromagnetic topological insulator with $e$ as the elementary charge and $T$ as the precession period. This significant magnetization is related to the global properties of the electronic geometric phases in the parameter space spanned by $\mathbit{S}$ and momentum $\mathbit{k}$. When the pumped magnetization is inhomogeneous, induced by spin textures or electronic topological phase domains, a dissipationless charge current is also pumped. At last, we discuss the boundary contributions from the spin-driving edge states, which are intricately linked to the gauge-dependent quantum uncertainty of the Chern-Simons form.
Phys. Rev. Lett. 134, 176702 (2025)
Magnetism, Spin pumping, Topological materials
Collective Optical Properties of Moir'e Excitons
Research article | Collective effects in quantum optics | 2025-04-30 06:00 EDT
Tsung-Sheng Huang, Yu-Xin Wang (王语馨), Yan-Qi Wang, Darrick Chang, Mohammad Hafezi, and Andrey Grankin
We propose that excitons in moir'e transition metal dichalcogenide bilayers offer a promising platform for investigating collective radiative properties. While some of these optical properties resemble those of cold atom arrays, moir'e excitons extend to the deep subwavelength limit, beyond the reach of current optical lattice experiments. Remarkably, we show that the collective optical properties can be exploited to probe certain correlated electron states without requiring subwavelength spatial resolution. Specifically, we illustrate that the Wigner crystal states of electrons doped into these bilayers act as an emergent periodic potential for excitons. Moreover, the collective dissipative excitonic bands and their associated Berry curvature can reveal various charge orders that emerge at the corresponding electronic doping. Our Letter provides a promising pathway for future research on the interplay between collective effects and strong correlations involving moir'e excitons.
Phys. Rev. Lett. 134, 176901 (2025)
Collective effects in quantum optics, Doping effects, Excitons, Light-matter interaction, Nanophotonics, Topological effects in photonic systems, Transition metal dichalcogenides, Twisted heterostructures, Wigner crystal
Contrasting Light-Induced Spin Torque in Antiferromagnetic and Altermagnetic Systems
Research article | Light-induced magnetic effects | 2025-04-30 06:00 EDT
Jian Zhou and Chunmei Zhang
Light-matter interaction has become one of the promising routes to manipulating various physical features of quantum materials in an ultrafast kinetics. In this Letter, we focus on the nonlinear optical effects of the spintronic behavior in antiferromagnetic (AFM) and altermagnetic (AM) systems with compensated magnetic moments, which has been extensively attractive for their potential applications. With vanishing net magnetic moments, one of the main concerns is how to distinguish and disentangle AFMs and AMs in experiments, as they usually behave similarly in many susceptibility measurements. To address this challenge, we propose that linearly polarized light could trigger contrasting nonequilibrium local spin torques in these systems, unraveling hidden light-induced spintronic behaviors. In general, one could achieve light-induced spin canting in AMs, but only N'eel vector torques in AFMs. We scrutinize and enumerate their symmetry constraints of all 122 magnetic point groups. We also adopt low energy Hamiltonian models and first-principles calculations on two representative materials to illustrate our theory. Our work provides a new perspective for the design and optimization of spintronic devices.
Phys. Rev. Lett. 134, 176902 (2025)
Light-induced magnetic effects, Magnetic order, Altermagnets, Antiferromagnets, Density functional theory, Tight-binding model, k dot p method
Statistical Mechanics of Transfer Learning in Fully Connected Networks in the Proportional Limit
Research article | Classical statistical mechanics | 2025-04-30 06:00 EDT
Alessandro Ingrosso, Rosalba Pacelli, Pietro Rotondo, and Federica Gerace
Tools from spin glass theory such as the replica method help explain the efficacy of transfer learning.
Phys. Rev. Lett. 134, 177301 (2025)
Classical statistical mechanics, Disordered systems, Deep learning, Machine learning
Quantum Delocalization Enables Water Dissociation on Ru(0001)
Research article | Adsorption | 2025-04-30 06:00 EDT
Yu Cao, Jiantao Wang, Mingfeng Liu, Yan Liu, Hui Ma, Cesare Franchini, Yan Sun, Georg Kresse, Xing-Qiu Chen, and Peitao Liu
We revisit the long-standing question of whether water molecules dissociate on the Ru(0001) surface through nanosecond-scale path-integral molecular dynamics simulations on a sizable supercell. This is made possible through the development of an efficient and reliable machine-learning potential with near first-principles accuracy, overcoming the limitations of previous ab initio studies. We show that the quantum delocalization associated with nuclear quantum effects enables rapid and frequent proton transfers between water molecules, thereby facilitating the water dissociation on Ru(0001). This work provides the direct theoretical evidence of water dissociation on Ru(0001), resolving the enduring issue in surface sciences and offering crucial atomistic insights into water-metal interfaces.
Phys. Rev. Lett. 134, 178001 (2025)
Adsorption, Interatomic & molecular potentials, Surface & interfacial phenomena, Water, First-principles calculations, Machine learning, Molecular dynamics
Heterogeneous Dynamics in Shear Thickening Colloids Revealed by Intrinsic Heterodyne Correlation Spectroscopy
Research article | Rheology | 2025-04-30 06:00 EDT
James P. Horwath, Hongrui He, Jonghun Lee, Zhang Jiang, Suman Chakraborty, Qingteng Zhang, Eric M. Dufresne, Mark Sutton, Alec Sandy, Suresh Narayanan, and Xiao-Min Lin
Shear induced frictional networks have been proposed to be responsible for the emergence of discontinuous shear thickening (DST) in complex fluids. However, little experimental evidence exists to support this model directly. Here, using x-ray photon correlation spectroscopy (XPCS), we show the existence of an intrinsic heterodyne feature during shear cessation, which originates from the relative motion of mobile particles against an aggregated or jammed network induced by shear thickening. Upon removing the shear, the shear stress dissipates rather quickly in a two-step fashion, whereas the heterogeneous particle dynamics persist much longer with the relative velocity decaying slowly with time as ${t}^{- 1}$. More importantly, both continuous shear thickening (CST) and DST show similar heterodyne features, indicating the intrinsic mechanisms causing shear thickening are similar in nature.
Phys. Rev. Lett. 134, 178202 (2025)
Rheology, Colloids, Shear thickening, X-ray photon correlation spectroscopy
Self-Organization and Memory in a Disordered Solid Subject to Random Driving
Research article | Aging | 2025-04-30 06:00 EDT
Muhittin Mungan, Dheeraj Kumar, Sylvain Patinet, and Damien Vandembroucq
We consider self-organization and memory formation in a mesoscopic model of an amorphous solid subject to a protocol of random shear confined to a strain range $\pm{}{\epsilon}_{\mathrm{max}}$. We develop proper readout protocols to show that the response of the driven system self-organizes to retain a memory of the strain range, which can be subsequently retrieved. Our findings generalize previous results obtained upon oscillatory driving and suggest that self-organization and memory formation of disordered materials can emerge under more general conditions, such as a disordered system interacting with its fluctuating environment. Self-organization results in a correlation between the dynamics of the system and its environment, providing thereby an elementary mechanism for sensing. We conclude by discussing our results and their potential relevance for the adaptation of simple organisms lacking a brain to changing environments.
Phys. Rev. Lett. 134, 178203 (2025)
Aging, Applications of soft matter, Biological information processing, Mechanical deformation, Nonequilibrium statistical mechanics, Plastic deformation, Plasticity, Self-organized systems, Shear deformation, Amorphous materials, Disordered systems, Coarse graining, Materials modeling
Integer Defects, Flow Localization, and Bistability on Curved Active Surfaces
Research article | Cell mechanics | 2025-04-30 06:00 EDT
Rushikesh Shinde, Raphaël Voituriez, and Andrew Callan-Jones
Biological surfaces, such as developing epithelial tissues, exhibit in-plane polar or nematic order and can be strongly curved. Recently, integer ($+1$) topological defects have been identified as morphogenetic hotspots in living systems. Yet, while $+1$ defects in active matter on flat surfaces are well understood, the general principles governing curved active defects remain unknown. Here, we study the dynamics of integer defects in an extensile or contractile polar fluid on two types of morphogenetically relevant substrates: (i) a cylinder terminated by a spherical cap, and (ii) a bump on an otherwise flat surface. Because the Frank elastic energy on a curved surface generically induces a coupling to deviatoric curvature, $\mathcal{D}$ (difference between squared principal curvatures), a $+1$ defect is induced on both surface types. We find that $\mathcal{D}$ leads to surprising effects including localization of orientation gradients and active flows, and particularly for contractility, to hysteresis and bistability between quiescent and flowing defect states.
Phys. Rev. Lett. 134, 178401 (2025)
Cell mechanics, Morphogenesis, Active defects, Active nematics, Active polar gels
Erratum: Evidence for $CP$ Violation in ${B}^{+}\rightarrow p\overline{p}{K}^{+}$ Decays [Phys. Rev. Lett. 113, 141801 (2014)]
Correction | | 2025-04-30 06:00 EDT
R. Aaij et al. (LHCb Collaboration)
et al.
Phys. Rev. Lett. 134, 179901 (2025)
Physical Review X
Modular Autonomous Virtualization System for Two-Dimensional Semiconductor Quantum Dot Arrays
Research article | Quantum control | 2025-04-30 06:00 EDT
Anantha S. Rao, Donovan Buterakos, Barnaby van Straaten, Valentin John, Cécile X. Yu, Stefan D. Oosterhout, Lucas Stehouwer, Giordano Scappucci, Menno Veldhorst, Francesco Borsoi, and Justyna P. Zwolak
Machine learning automates the control of a large and highly connected array of semiconductor quantum dots.
Phys. Rev. X 15, 021034 (2025)
Quantum control, Quantum information architectures & platforms, Quantum information with solid state qubits, Quantum dots, Semiconductor compounds, Semiconductors, Machine learning
Strongly Interacting, Two-Dimensional, Dipolar Spin Ensembles in (111)-Oriented Diamond
Research article | Quantum sensing | 2025-04-30 06:00 EDT
Lillian B. Hughes, Simon A. Meynell, Weijie Wu, Shreyas Parthasarathy, Lingjie Chen, Zhiran Zhang, Zilin Wang, Emily J. Davis, Kunal Mukherjee, Norman Y. Yao, and Ania C. Bleszynski Jayich
Dense ensembles of nitrogen-vacancy centers in diamond with strong dipolar interactions and controlled dimensionality offer a new platform for advancing quantum sensing and simulation.
Phys. Rev. X 15, 021035 (2025)
Quantum sensing, Quantum simulation, Nitrogen vacancy centers in diamond, Chemical vapor deposition
Review of Modern Physics
CODATA recommended values of the fundamental physical constants: 2022
Research article | Determination of fundamental constants | 2025-04-30 06:00 EDT
Peter J. Mohr, David B. Newell, Barry N. Taylor, and Eite Tiesinga
This review contains the 2022 self-consistent set of values of the constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA). The CODATA values are based on a least-squares adjustment that takes into account all data available up to the end of 2022. Details of the data selection and methodology are described.
Rev. Mod. Phys. 97, 025002 (2025)
Determination of fundamental constants
arXiv
Electrical switching of an unconventional odd parity magnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Qian Song, Srdjan Stavrić, Paolo Barone, Andrea Droghetti, Daniil S. Antonenko, Jörn W. F. Venderbos, Connor A. Occhialini, Batyr Ilyas, Emre Ergeçen, Nuh Gedik, Sang-Wook Cheong, Rafael M. Fernandes, Silvia Picozzi, Riccardo Comin
Magnetic states with zero magnetization but non-relativistic spin splitting are outstanding candidates for the next generation of spintronic devices. Their electron-volt (eV) scale spin splitting, ultrafast spin dynamics and nearly vanishing stray fields make them particularly promising for several applications. A variety of such magnetic states with nontrivial spin textures have been identified recently, including even-parity d, g, or i-wave altermagnets and odd-parity p-wave magnets. Achieving voltage-based control of the nonuniform spin polarization of these magnetic states is of great interest for realizing energyefficient and compact devices for information storage and processing. Spin-spiral type-II multiferroics are optimal candidates for such voltage-based control, as they exhibit an inversion-symmetry-breaking magnetic order which directly induces ferroelectric polarization, allowing for symmetry protected cross-control between spin chirality and polar order. Here we combine photocurrent measurements, first-principle calculations and group-theory analysis to provide direct evidence that the spin polarization of the spin-spiral type-II multiferroic NiI2 exhibits odd-parity character connected to the spiral chirality. The symmetry-protected coupling between chirality and polar order enables electrical control of a primarily non-relativistic spin polarization. Our findings represent the first direct observation of unconventional odd-parity magnetism in a spin-spiral type-II multiferroic, and open a new frontier of voltage-based switching of non-relativistic spin polarization in compensated magnets.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Extracting average properties of disordered spin chains with translationally invariant tensor networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-01 20:00 EDT
Kevin Vervoort, Wei Tang, Nick Bultinck
We develop a tensor network-based method for calculating disorder-averaged expectation values in random spin chains without having to explicitly sample over disorder configurations. The algorithm exploits statistical translation invariance and works directly in the thermodynamic limit. We benchmark our method on the infinite-randomness critical point of the random transverse field Ising model.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Enhanced superconductivity in X4H15compounds via hole-doping at ambient pressure
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-01 20:00 EDT
Kun Gao, Wenwen Cui, Tiago F. T. Cerqueira, Hai-ChenWang, Silvana Botti, Miguel A. L. Marque
This study presents a computational investigation of X4H15 compounds (where X represents a metal) as potential superconductors at ambient conditions or under pressure. Through systematic density functional theory calculations and electron-phonon coupling analysis, we demonstrate that electronic structure engineering via hole doping dramatically enhances the superconducting properties of these materials. While electron-doped compounds with X4+ cations (Ti, Zr, Hf, Th) exhibit modest transition temperatures of 1-9 K, hole-doped systems with X3+cations (Y, Tb, Dy, Ho,Er, Tm, Lu) show remarkably higher values of approximately 50 K at ambient pressure. Superconductivity in hole-doped compounds originates from stronger coupling between electrons and both cation and hydrogen phonon modes. Although pristine X3+4H15compounds are thermodynamically unstable, we propose a viable synthesis route via controlled hole doping of the charge-compensated YZr3H15 compound. Our calculations predict that even minimal concentrations of excess Y could induce high-temperature superconductivity while preserving structural integrity. This work reveals how strategic electronic structure modulation can optimize superconducting properties in hydride systems, establishing a promising pathway toward practical high-temperature conventional super-conductors at ambient pressure
Superconductivity (cond-mat.supr-con)
Low Resistance P-type Contacts to Monolayer WSe$_2$ through Chlorinated Solvent Doping
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Lauren Hoang, Robert K.A. Bennett, Anh Tuan Hoang, Tara Pena, Zhepeng Zhang, Marisa Hocking, Ashley P. Saunders, Fang Liu, Eric Pop, Andrew J. Mannix
Tungsten diselenide (WSe$ 2$ ) is a promising p-type semiconductor limited by high contact resistance ($ R\textrm{C}$ ) and the lack of a reliable doping strategy. Here, we demonstrate that exposing WSe$ 2$ to chloroform provides simple and stable p-type doping. In monolayer WSe$ 2$ transistors with Pd contacts, chloroform increases the maximum hole current by over 100$ \times$ (>200 $ \mu$ A/$ \mu$ m), reduces $ R\textrm{C}$ to ~2.5 k$ \Omega\cdot\mu$ m, and retains an on/off ratio of $ 10^{10}$ at room temperature. These improvements persist for over 8 months, survive annealing above 150 °C, and remain effective down to 10 K, enabling a cryogenic $ R\textrm{C}$ of ~1 k$ \Omega\cdot\mu$ m. Density functional theory indicates that chloroform strongly physisorbs to WSe$ _2$ , inducing hole doping with minimal impact on the electronic states between the valence band and conduction band edges. Auger electron spectroscopy and atomic force microscopy reveal that chloroform intercalates at the WSe$ _2$ interface with the gate oxide, contributing to doping stability and mitigating interfacial dielectric disorder. This robust, scalable approach enables high-yield WSe$ _2$ transistors with good p-type performance.
Materials Science (cond-mat.mtrl-sci)
Electrical Side-Gate Control of Anisotropic Magnetoresistance and Magnetic Anisotropy in a Composite Multiferroic
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Katherine Johnson, Michael Newburger, Michael Page, Roland K. Kawakami
Composite multiferroics consisting of a ferroelectric material interfaced with a ferromagnetic material can function above room temperature and exhibit improved magnetoelectric (ME) coupling compared to single-phase multiferroic materials, making them desirable for applications in energy efficient electronic devices. In this study, we demonstrate electrical side-gate control of magnetoresistance and magnetic anisotropy in single-crystalline ferromagnetic Fe$ _{0.75}$ Co$ _{0.25}$ thin films grown on ferroelectric PMN-PT (001) substrates by molecular beam epitaxy. Fe$ _{0.75}$ Co$ _{0.25}$ is selected due to its large magnetoelastic coupling and low magnetic damping. We find that the magnetoresistance curves of patterned Fe$ _{0.75}$ Co$ _{0.25}$ films are controlled by voltages applied to electrostatic side gates. Angle-dependent magnetoresistance scans reveal that the origin of this effect is strain-mediated variation of the magnetic anisotropy due to piezoelectric effects in the PMN-PT. This electrical control of magnetic properties could serve as a building block for future magnetoelectronic and magnonic devices.
Materials Science (cond-mat.mtrl-sci)
9 pages, 6 figures
Power Transfer in Magnetoelectric Resonators: a Combined Analytical and Finite Element Study
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Emma Van Meirvenne, Frederic Vanderveken, Daniele Narducci, Bart Sorée, Florin Ciubotaru, Christoph Adelmann
We present an analytical model for power transfer in a magnetoelectric film bulk acoustic resonator (FBAR) comprising a piezoelectric-magnetostrictive bilayer. The model describes the power flow between the elastic and magnetic systems, quantifying the transduction efficiency when the FBAR operates as a magnetic transducer. By applying the model to example systems using piezoelectric ScAlN and magnetostrictive CoFeB, Ni, or Terfenol-D layers, we demonstrate the potential for achieving high efficiencies in magnetoelectric transducers, rendering them ideal for efficient ferromagnetic resonance excitation. The validity of the model’s assumptions is confirmed through comparison with a numerical finite element resonator model in COMSOL\texttrademark. The finite element model further enables a comprehensive study of the resonator’s dynamic behavior, including transient and steady-state regimes, and the identification of resonant frequencies within the system.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
39 pages, 8 figures
Tunable stacking-driven topological phase transitions in pnictide layers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Arjyama Bordoloi, Daniel Kaplan, Sobhit Singh
Nonmagnetic topological insulators (TIs) are known for their robust metallic surface/edge states that are protected by time-reversal symmetry, making them promising candidates for next-generation spintronic and nanoelectronic devices. Traditional approaches to realizing TIs have focused on inducing band inversion via strong spin-orbit coupling (SOC), yet many materials with substantial SOC often remain topologically trivial. In this work, we present a materials-design strategy for engineering topologically non-trivial phases, e.g., quantum spin Hall phases, by vertically stacking topologically trivial Rashba monolayers in an inverted fashion. Using BiSb as a prototype system, we demonstrate that while the BiSb monolayer is topologically trivial (despite having significant SOC), an inverted BiSb-SbBi bilayer configuration realizes a non-trivial topological phase with enhanced spin Hall conductivity. We further reveal a delicate interplay between the SOC strength and the interlayer electron tunneling that governs the emergence of a nontrivial topological phase in the bilayer heterostructure. This phase can be systematically tuned using an external electric field, providing an experimentally accessible means of controlling the system’s topology. Our magnetotransport studies further validate this interplay, by revealing g-factor suppression and the emergence a zeroth Landau level. Notably, the inverted bilayer heterostructure exhibits a robust and tunable spin Hall effect, with performance comparable to that of state-of-the-art materials. Thus, our findings unveil an alternative pathway for designing and engineering functional properties in 2D topological systems using topologically trivial constituent monolayers.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
7 pages (main text) + appendices. Comments appreciated
Phase Diagram of UTe$_2$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-01 20:00 EDT
The pressure-temperature phase diagram of superconducting UTe$ _2$ with three lines of the second-order phase transitions cannot be explained in terms of successive transitions to superconducting states with a decrease in symmetry. The problem is solved using a two-band description of the superconducting state of UTe$ _2$ .
Superconductivity (cond-mat.supr-con)
3 pages, 2 figures
Determining the Nature of Magnetism in Altermagnetic Candidate RuO$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Tiema Qian, Aya Rutherford, Eun Sang Choi, Haidong Zhou, Boris Maiorov, Minseong Lee, Christopher A. Mizzi
The terminology “altermagnetism” has recently been adopted to describe collinear magnetic order with no net magnetization and non-relativisitic, momentum-dependent spin-splitting. The archetypal material used to theoretically explore altermagnetism is RuO$ _2$ , but there has been significant debate as to whether RuO$ _2$ possesses magnetic, let alone altermagnetic, order. To address questions surrounding the nature of magnetism in RuO$ _2$ , we combine symmetry-sensitive torque magnetometry and magnetization measurements in single crystals. The data are inconsistent with collinear magnetic order possessing a Néel vector along the $ c-$ axis. Torque magnetometry further demonstrates an isotropic magnetic susceptibility within the $ ab-$ plane, indicative of neither a Néel vector within the $ ab-$ plane nor a field-induced Néel vector reorientation. Magnetic quantum oscillations from both techniques reveal a nearly spherical Fermi surface pocket at the Brillouin zone center, in agreement with paramagnetic electronic structure calculations. Taken together, these data indicate no detectable long-range magnetic order and, by extension, suggest no altermagnetism in high-quality RuO$ _2$ single crystals.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
From hierarchical triangular spin liquid to multi-$q$ spin texture in spinel GeFe$_2$O$_4$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-01 20:00 EDT
L. Chaix, J. Robert, E. Chan, E. Ressouche, S. Petit, C. V. Colin, R. Ballou, J. Ollivier, L.-P. Regnault, E. Lhotel, V. Cathelin, S. Lenne, C. Cavanel, F. Damay, E. Suard, P. Strobel, C. Darie, S. deBrion, V. Simonet
Combining macroscopic measurements, neutron scattering and modeling, we identify in the GeFe$ _2$ O$ _4$ spinel a correlated paramagnetic state resulting from the predominance of third-neighbor antiferromagnetic interactions. These interactions materialize 4 isolated families of triangular planes with 120$ ^{\circ}$ spins emerging from the underlying pyrochlore lattice. At lower temperatures, a phase transition occurs from this hierarchical spin liquid to a non-coplanar spin texture that is characterized by 6 propagating vectors. This unusual multi-$ q$ order is triggered by the presence of weaker interactions up to the sixth neighbors. The system is remarkably successful in coupling the different triangular planes while maintaining their two-dimensional 120$ ^{\circ}$ order. Our study highlights the hierarchy of interactions involved in GeFe$ _2$ O$ _4$ , which is singular among spinel compounds since first-neighbor interactions are only a small fraction of the dominant third neighbor ones.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 3 figures
The Relevance of Non-axiality and Low-lying Excited States for Slow Magnetic Relaxation in Pentagonal-bipyramidal Erbium(III) Complexes Probed by High-frequency EPR
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-01 20:00 EDT
J. Arneth, L. Spillecke, C. Koo, T. A. Bazhenova, E. B. Yagubskii, R. Klingeler
High-frequency/high-field electron paramagnetic resonance studies on a series of seven-coordinate pentagonal-bipyramidal (PBP) erbium(III) complexes Er(DAPMBH/H$ _2$ DAPS)X (H$ _2$ DAPMBH = 2,6-diacetylpyridine bis-4-methoxy benzoylhydrazone, H$ _4$ DAPS = 2,6-diacetylpyridine bis-(salicylhydrazone)) demonstrate the effects of different apical ligands (X = (H$ _2$ O)Cl (1), (CH$ _3$ OH)N$ _3$ (2), Cl$ _2$ (3)) on the local magnetic anisotropy of the central Er(III) ions. In particular, we report direct experimental determination of the effective $ g$ -values and zero field splittings of the energetically low-lying Kramers doublets. Our quantitative determination of the magnetic anisotropy highlights the relevance of an axial $ g$ -tensor for SMM behaviour and suggests that fast magnetic relaxation is mainly driven by a thermally assisted quantum tunnelling process via low-lying excited states.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 7 figures
Anyonization of bosons in one dimension: an effective swap model
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-01 20:00 EDT
Botao Wang, Amit Vashisht, Yanliang Guo, Sudipta Dhar, Manuele Landini, Hanns-Christoph Nägerl, Nathan Goldman
Anyons emerge as elementary excitations in low-dimensional quantum systems and exhibit behavior distinct from bosons or fermions. Previous models of anyons in one dimension (1D) are mainly categorized into two types: those that rely on nontrivial scattering behavior, and those based on density-dependent hopping processes in discrete lattices. Here, we introduce a novel framework for realizing anyonic correlations using the internal degrees of freedom of a spinor quantum gas. We propose a “swap” model, which assigns a complex phase factor to the swapping processes between two different species, referred to as “host particles” and “impurities”. The anyonic characteristics are demonstrated through the one-body correlator of the impurity, using a spin-charge separation analysis. For a single impurity, our swap model can be effectively implemented by applying tilt potentials in a strongly interacting quantum gas [Dhar et al., arXiv:2412.21131]. We further explore the dynamical properties of anyonic correlations and extend our analysis to the case of multiple impurities. Our work provides new avenues for engineering many-body anyonic behavior in quantum simulation platforms.
Quantum Gases (cond-mat.quant-gas), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
5 pages, 4 figures plus supplementary. BW and AV contributed equally
Surface Structure and Surface State of a Tight-Binding Model on a Diamond Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-01 20:00 EDT
Surface states of a tight-binding model with nearest-neighbor hopping on a diamond lattice of finite thickness are investigated. We consider systems with (001), (110), and (111) surfaces. Even if the surface direction is fixed, there is freedom to choose the surface structure due to the two-sublattice nature of a diamond lattice. The existence of surface states is governed by the topology of the matrix elements of the bulk Hamiltonian. In this sense, the existence of surface states is determined by the bulk Hamiltonian. However, the matrix elements depend on the choice of the unit cell, which should be chosen to conform to the surface structure. Thus, the surface states depend on the surface structure. We find that for each surface direction, there are two choices of surface structure, and depending on the chosen structure, the corresponding surface states emerge in distinct regions of the surface Brillouin zone.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 12 figures
Database and deep-learning scalability of anharmonic phonon properties by automated brute-force first-principles calculations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Masato Ohnishi, Tianqi Deng, Pol Torres, Zhihao Xu, Terumasa Tadano, Haoming Zhang, Wei Nong, Masatoshi Hanai, Zhiting Tian, Ming Hu, Xiulin Ruan, Ryo Yoshida, Toyotaro Suzumura, Lucas Lindsay, Alan J. H. McGaughey, Tengfei Luo, Kedar Hippalgaonkar, Junichiro Shiomi
Understanding the anharmonic phonon properties of crystal compounds – such as phonon lifetimes and thermal conductivities – is essential for investigating and optimizing their thermal transport behaviors. These properties also impact optical, electronic, and magnetic characteristics through interactions between phonons and other quasiparticles and fields. In this study, we develop an automated first-principles workflow to calculate anharmonic phonon properties and build a comprehensive database encompassing more than 6,000 inorganic compounds. Utilizing this dataset, we train a graph neural network model to predict thermal conductivity values and spectra from structural parameters, demonstrating a scaling law in which prediction accuracy improves with increasing training data size. High-throughput screening with the model enables the identification of materials exhibiting extreme thermal conductivities – both high and low. The resulting database offers valuable insights into the anharmonic behavior of phonons, thereby accelerating the design and development of advanced functional materials.
Materials Science (cond-mat.mtrl-sci)
Rate Analysis of Dislocations Overcoming Elastic Barriers: Effects of Entropy and Langevin Friction via Kramers Theory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Mohammadhossein Nahavandian, Liam Myhill, Enrique Martinez
Thermal activation of dislocations is critical for predicting the mechanical response of materials under common experimental conditions. According to transition state theory (TST), the rate for the system to overcome free energy barriers depends on an attempt frequency, activation free energy, and temperature. We computed the rate for edge and screw dislocation dipoles to overcome their interaction fields at various temperatures, Langevin friction coefficients, and shear stresses using Molecular Dynamics (MD), Schoeck entropy formalism and compared with Kramers rate theory. Rates computed dynamically show dependence on Langevin friction, increasing with weaker friction and showing more correlated events. Statically, using Schoeck formalism and computing the minimum energy path (MEP), we found significant entropic effects at high temperature and a transition from Arrhenius to non-Arrhenius behavior near the critical resolved shear stress values for both edge and screw characters.
Materials Science (cond-mat.mtrl-sci), Atomic and Molecular Clusters (physics.atm-clus)
Analytical model and experimental validation for nonlinear mechanical response of aspirated elastic shells
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-01 20:00 EDT
Kazutoshi Masuda, Miho Yanagisawa
We developed a physics-based analytical model to describe the nonlinear mechanical response of aspirated elastic shells. By representing the elastic energy through a stretching modulus, $ K$ , and a dimensionless ratio, $ \delta$ , capturing the balance between stretching and bending energies, the model reveals mechanical behaviors extending beyond conventional approaches. Validated across microscale droplets and macroscale silicone sheets by fitting experimental force-displacement curves, this approach provides accurate, scalable characterization of deformed elastic shells. This framework advances our understanding of soft thin-shell mechanics, with broad applications in probing living cells and designing soft materials.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
6 pages, 4 figures
NEP89: Universal neuroevolution potential for inorganic and organic materials across 89 elements
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Ting Liang, Ke Xu, Eric Lindgren, Zherui Chen, Rui Zhao, Jiahui Liu, Benrui Tang, Bohan Zhang, Yanzhou Wang, Keke Song, Penghua Ying, Haikuan Dong, Shunda Chen, Paul Erhart, Zheyong Fan, Tapio Ala-Nissila, Jianbin Xu
Machine-learned potentials (MLPs) offer near-first-principles accuracy for atomistic simulations, but many models are material-specific or computationally intensive, limiting their broader use. Here, we introduce NEP89, a foundation model based on the neuroevolution potential (NEP) architecture, delivering empirical-potential-like speed and high accuracy across 89 chemical elements. A compact yet comprehensive training dataset covering inorganic and organic materials across 89 elements was curated through descriptor-space subsampling and an iterative active-learning-like process applied to multiple datasets. We rigorously evaluated NEP89’s predictive performance against representative foundation models, demonstrating its reliability and competitive accuracy across diverse benchmark studies. NEP89 is 3-4 orders of magnitude more computationally efficient than comparable models, enabling previously impractical large-scale atomistic simulations for both inorganic and organic systems. It also supports fine-tuning on small datasets, allowing rapid adaptation to user-specific applications. This work marks a significant advancement in MLPs, enabling high-performance atomistic simulations across diverse research fields and communities.
Materials Science (cond-mat.mtrl-sci)
14 pages, 8 figures
Towards Space Group Determination from EBSD Patterns: The Role of Deep Learning and High-throughput Dynamical Simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Alfred Yan, Muhammad Nur Talha Kilic, Gert Nolze, Ankit Agrawal, Alok Choudhary, Roberto dos Reis, Vinayak Dravid
The design of novel materials hinges on the understanding of structure-property relationships. However, our capability to synthesize a large number of materials has outpaced the ability and speed needed to characterize them. While the overall chemical constituents can be readily known during synthesis, the structural evolution and characterization of newly synthesized samples remains a bottleneck for the ultimate goal of high throughput nanomaterials discovery. Thus, scalable methods for crystal symmetry determination that can analyze a large volume of material samples within a short time-frame are especially needed. Kikuchi diffraction in the SEM is a promising technique for this due to its sensitivity to dynamical scattering, which may provide information beyond just the seven crystal systems and fourteen Bravais lattices. After diffraction patterns are collected from material samples, deep learning methods may be able to classify the space group symmetries using the patterns as input, which paired with the elemental composition, would help enable the determination of the crystal structure. To investigate the feasibility of this solution, neural networks were trained to predict the space group type of background corrected EBSD patterns. Our networks were first trained and tested on an artificial dataset of EBSD patterns of 5,148 different cubic phases, created through physics-based dynamical simulations. Next, Maximum Classifier Discrepancy, an unsupervised deep learning-based domain adaptation method, was utilized to train neural networks to make predictions for experimental EBSD patterns. We introduce a relabeling scheme, which enables our models to achieve accuracy scores higher than 90% on simulated and experimental data, suggesting that neural networks are capable of making predictions of crystal symmetry from an EBSD pattern.
Materials Science (cond-mat.mtrl-sci), Computer Vision and Pattern Recognition (cs.CV)
33 pages, preliminary version
Higgs mode in two-dimensional coherent spectroscopy of weak-coupling antiferromagnets
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-01 20:00 EDT
Jiyu Chen, Naoto Tsuji, Philipp Werner
Two-dimensional coherent spectroscopy (2DCS) provides insights into the nonlinear response of correlated lattice systems. We simulate multipulse excitations in the Hubbard model using nonequilibrium dynamical mean-field theory to extract the 2DCS signal of weak-coupling antiferromagnets with and without disorder. By comparing calculations with static and dynamic Hartree terms, and analyzing the waiting-time dependence of the signal, we identify the contribution of the collective amplitude (Higgs) mode to the spectroscopic features and the relevant underlying processes. With broadband pulses, the rephasing and nonrephasing peaks at the gap energy are found to be of predominant Higgs character, while the two-quantum signals originate from single-particle excitations. Using narrow-band pulses, we also demonstrate a strong enhancement of these Higgs-related signals at a pulse frequency of half the gap size.
Strongly Correlated Electrons (cond-mat.str-el)
From fluttering to drifting in inertialess sedimentation of achiral particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-01 20:00 EDT
Christian Vaquero-Stainer, Tymoteusz Miara, Anne Juel, Matthias Heil, Draga Pihler-Puzović
There has been much recent interest in the chiral motion of achiral particles that sediment in a viscous fluid in a regime where inertial effects can be neglected. This occurs in a broad range of applications such as those involving biological objects like algae, ultra-thin graphene flakes, or colloidal suspensions. It is known that articles with two planes of symmetry can be categorised as settlers'', drifters’’ or flutterers'', where the latter sediment along chiral trajectories despite their achiral shapes. Here we analyse the sedimentation of circular disks bent into a U-shape (flutterers’’) and show how their behaviour changes when we break one of their symmetries by pinching the disks along their axis. The fluttering'' behaviour is found to be robust to such shape changes, with the trajectories now evolving towards helical paths. However, the behaviour changes when the degree of pinching becomes too strong, at which point the particles become drifters’’ which sediment steadily without rotation. We establish criteria for the transition between the two types of behaviour and confirm our predictions in experiments. Finally, we discuss the implications of our observations for the dispersion of dilute suspensions made of such particles.
Soft Condensed Matter (cond-mat.soft)
Thermodynamic formulation of the spin magnetic octupole moment in bulk crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Jun Ōiké, Robert Peters, Koki Shinada
The discovery of unconventional antiferromagnets, such as altermagnets, has drawn significant attention to higher-rank magnetic multipoles. Despite the advances in research, a fundamental understanding of multipole moments, particularly octupole moments, remains limited due to the challenges of accurately treating the position operator in bulk crystals, which is integral to their definitions. In this paper, we overcome this problem by using a thermodynamic relation and derive a formula of the spin magnetic octupole moment (SMOM) that can be used in bulk crystals. The resulting formula is gauge invariant and satisfies Středa formulas, which relate the SMOM to the spin magnetoelectric dipole-quadrupole susceptibilities. Furthermore, we apply this formula to several models and examine the fundamental properties of the SMOM. One particularly important property is that the SMOM of $ d$ -wave altermagnets is dominated by nonrelativistic SMOMs regardless of spin-orbit coupling. Moreover, these nonrelativistic SMOMs exhibit a Néel order dependence that is predicted by the Landau theory of $ d$ -wave altermagnetism [Phys. Rev. Lett. $ \textbf{132}$ , 176702 (2024)].
Materials Science (cond-mat.mtrl-sci)
14 pages, 6 figures
Ultralow-Temperature Thermodynamics and Optical Coherence of Narrow Linewidth Optical Emitters
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Thierry Klein (NEEL), C Marcenat (NEEL), D Serrano (ENSCP), P Goldner (ENSCP), M T Hartman (LNE - SYRTE), B Fang (LNE - SYRTE), Y Le Coq (LIPhy), S Seidelin (NEEL)
The coherence properties of optical emitters in crystals are critical for quantum technologies and optical frequency metrology. Cooling to sub-kelvin temperatures can significantly enhance their coherence, making it essential to identify the key parameters governing emitter and host crystal behavior in this ultra cold regime. We investigate a Czochralski-grown europium doped yttrium orthosilicate crystal, and we report measurements of the heat capacity, a parameter fundamental to evaluating thermal noise limits in metrology schemes based on spectral hole stabilization in such samples. In parallel, we characterize optical coherence via photon echo measurements as a function of temperature. Below 1 K, where phonon contributions diminish, two-level systems (TLS) associated with crystal imperfections may emerge as a limiting factor. A linear-in-temperature term in the heat capacity serves as a signature of TLS, and from our data, we establish an upper bound on this contribution. This, combined with the optical homogeneous linewidth from photon-echo measurements being constant in the interval from 300 mK to 2 K demonstrates a minimal TLSrelated effects in our sample. These findings highlight the promise of ultralow-temperature operation for enhancing the performance of optical quantum devices based on doped crystals.
Materials Science (cond-mat.mtrl-sci)
Topotactical hydrogen induced single-band $d$-wave superconductivity in La$_2$NiO$_4$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-01 20:00 EDT
Ying Gao, Wenfeng Wu, Zhaoxin Liu, Karsten Held, Liang Si
La$ _2$ NiO$ _4$ is an antiferromagnetic insulator with a structural resemblance to its cuprate counterpart, La$ _2$ CuO$ _4$ . However, La$ _2$ CuO$ _4$ has a Cu$ ^{2+}$ or 3$ d^9$ electronic configuration that needs to be hole or electron doped for superconductivity, whereas La$ _2$ NiO$ _4$ is 3$ d^8$ with divalent Ni$ ^{2+}$ . Making a cuprate analog through conventional electron doping is impractical due to the rarity of trivalent substituents for La. In this work, we propose an alternative route: intercalating topotactical hydrogen which is possible through electric-field-controlled protonation and transforms La$ _2$ NiO$ 4$ into a 3$ d{x^2-y^2}$ single-band two-dimensional anti-ferromagnetic Mott insulator analogous to La$ _2$ CuO$ _4$ . This we find through density-functional theory and dynamical mean-field theory calculations. The furthergoing dynamical vertex approximation predicts that H-La$ _2$ NiO$ _4$ can host $ d$ -wave superconductivity under 15% hole doping with a critical temperature above 20,K. Our findings not only suggest a new method for tuning the electronic structure of layered nickelates but also provides theoretical evidence for a new nickelate superconductor, awaiting experimental synthesis.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 5 figures, 1 table
Quantum theory of magnetic octupole in periodic crystals and characterization of time-reversal-symmetry breaking antiferromagnetism
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Magnetic multipoles have been recognized as order parameters characterizing magnetic structure in solids, with magnetic dipole serving as canonical examples in ferromagnets. Recently, magnetic octupoles have been proposed as the order parameters of time-reversal-symmetry breaking centrosymmetric antiferromagnets exhibiting nonrelativistic spin splitting, which is referred to as ``altermagnet’’. However, a gauge-invariant formulation of magnetic octupoles in crystalline solids remains elusive. Here, we present a gauge-invariant expression of spin magnetic octupoles in periodic crystals based on quantum mechanics and thermodynamics. Our expression reveals a contribution from an anisotropic magnetic dipole, which has the same symmetry as conventional spin and orbital magnetic dipoles but carries no net magnetization. We demonstrate that such an anisotropic magnetic dipole acts as an order parameter for antiferromagnets that exhibit the anomalous Hall effect.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Diffusion of intruders in a granular gas thermostatted by a bath of elastic hard spheres
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-01 20:00 EDT
Rubén Gómez González, Vicente Garzó
The Boltzmann kinetic equation is considered to compute the transport coefficients associated with the mass flux of intruders in a granular gas. Intruders and granular gas are immersed in a gas of elastic hard spheres (molecular gas). We assume that the granular particles are sufficiently rarefied so that the state of the molecular gas is not affected by the presence of the granular gas. Thus, the gas of elastic hard spheres can be considered as a thermostat (or bath) at a fixed temperature $ T_g$ . In the absence of spatial gradients, the system achieves a steady state where the temperature of the granular gas $ T$ differs from that of the intruders $ T_0$ (energy nonequipartition). Approximate theoretical predictions for the temperature ratios $ T/T_g$ and $ T_0/T_g$ and the kurtosis $ c$ and $ c_0$ associated with the granular gas and the intruders compare very well with Monte Carlo simulations for conditions of practical interest. For states close to the steady homogeneous state, the Boltzmann equation for the intruders is solved by means of the Chapman–Enskog method to first order in the spatial gradients. As expected, the diffusion transport coefficients are given in terms of the solutions of a set of coupled linear integral equations which are approximately solved by considering the first-Sonine approximation. In dimensionless form, the transport coefficients are nonlinear functions of the mass and diameter ratios, the coefficients of restitution, and the (reduced) bath temperature. Interestingly, previous results derived from a suspension model based on an effective fluid-solid interaction force are recovered when $ m/m_g\to \infty$ and $ m_0/m_g\to \infty$ , where $ m$ , $ m_0$ , and $ m_g$ are the masses of the granular, intruder, and molecular gas particle, respectively. Finally, as an application of our results, thermal diffusion segregation is exhaustively analysed.
Soft Condensed Matter (cond-mat.soft)
40 pages, 12 figures
Discrete time crystals detected by time-translation twist
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-01 20:00 EDT
Ryota Nakai, Taozhi Guo, Shinsei Ryu
We introduce a boundary condition twisted by time translation as a novel probe to characterize dynamical phases in periodically driven (Floquet) quantum systems. Inspired by twisted boundary conditions in equilibrium systems, this approach modifies the temporal evolution of the system upon completing a spatial loop, enabling the identification of distinct Floquet phases, including discrete time crystals (DTCs). By studying the spectral form factor (SFF) and its response to the twist, we uncover signatures of time-crystalline order, which exhibits periodic dependence on the twist parameter analogous to the Little-Parks effect in superconductors. We apply this framework to the kicked Ising model, demonstrating that our twist can distinguish time-crystalline phases.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
12 pages, 4 figures
High-Quality Ultra-Fast Total Scattering and Pair Distribution Function Data using an X-ray Free Electron Laser
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Adam F. Sapnik, Philip A. Chater, Dean S. Keeble, John S. O. Evans, Federica Bertolotti, Antonietta Guagliardi, Lise J. Støckler, Elodie A. Harbourne, Anders B. Borup, Rebecca S. Silberg, Adrien Descamps, Clemens Prescher, Benjamin D. Klee, Axel Phelipeau, Imran Ullah, Kárel G. Medina, Tobias A. Bird, Viktoria Kaznelson, William Lynn, Andrew L. Goodwin, Bo B. Iversen, Celine Crepisson, Emil S. Bozin, Kirsten M. Ø. Jensen, Emma E. McBride, Reinhard B. Neder, Ian Robinson, Justin Wark, Michal Andrzejewski, Ulrike Boesenberg, Erik Brambrink, Carolina Camarda, Valerio Cerantola, Sebastian Goede, Hauke Höppner, Oliver S. Humphries, Zuzana Konopkova, Naresh Kujala, Thomas Michelat, Motoaki Nakatsutsumi, Thomas R. Preston, Lisa Randolph, Andreas Schmidt, Cornelius Strohm, Minxue Tang, Ulf Zastrau, Karen Appel, David A. Keen
High-quality total scattering data, a key tool for understanding atomic-scale structure in disordered materials, require stable instrumentation and access to high momentum transfers. This is now routine at dedicated synchrotron instrumentation using high-energy X-ray beams, but it is very challenging to measure a total scattering dataset in less than a few microseconds. This limits their effectiveness for capturing structural changes that occur at the much faster timescales of atomic motion. Current X-ray free-electron lasers (XFELs) provide femtosecond-pulsed X-ray beams with maximum energies of approximately 24 keV, giving the potential to measure total scattering and the attendant pair distribution functions (PDFs) on femtosecond timescales. Here, we show that this potential has been realised using the HED scientific instrument at the European XFEL and present normalised total scattering data for 0.35 Å-1 < Q < 16.6 Å-1 and their PDFs from a broad spectrum of materials, including crystalline, nanocrystalline and amorphous solids, liquids, and clusters in solution. We analyse the data using a variety of methods, including Rietveld refinement, small-box PDF refinement, joint reciprocal-real space refinement, cluster refinement, and Debye scattering analysis. The resolution function of the setup is also thoroughly characterised. We conclusively show that high-quality data can be obtained from a single approximately 30 fs XFEL pulse. Our efforts not only significantly increase the existing maximum reported Q-range for an S(Q) measured at an XFEL but also mean that XFELs are now a viable X-ray source for the broad community of people using reciprocal space total scattering and PDF methods in their research.
Materials Science (cond-mat.mtrl-sci)
Exchange Surface Spin Waves in Type-A van der Waals Antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Zhoujian Sun, Fuxiang Li, Gerrit E. W. Bauer, Ping Tang
Surface spin waves in the short-wavelength regime enable ultrafast, nanoscale magnon-based devices. Here we report the emergence of surface spin-wave excitations within the bulk magnon band gap of type-A van der Waals antiferromagnets composed of antiferromagnetically coupled ferromagnetic monolayers. In contrast to the magnetostatic Damon-Eshbach modes in magnetic slabs, these surface waves are pure exchange modes owing to the reduced interlayer exchange coupling at surface layers, and thus persist in ultrathin multilayer stacks and at large wave numbers. We show that they can be efficiently excited by electromagnetic waves, with absorption power comparable to or even exceeding that of bulk modes. Moreover, their magnetic stray fields exhibit pronounced even-odd oscillations with the number of monolayers that should be observable by NV-center magnetometry.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Gate-tunable polarity inversions and three-fold rotation symmetry of the superconducting diode effect
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
William F. Schiela, Melissa Mikalsen, Daniel Crawford, Stefan Ilić, William M. Strickland, F. Sebastian Bergeret, Javad Shabani
The superconducting diode effect is an asymmetry in the critical current with respect to the supercurrent polarity. One impetus driving recent interest in the effect is its dependence on intrinsic or microscopic symmetry breaking mechanisms.
Here, we study the superconducting diode effect in gated planar Josephson junctions fabricated on a superconductor–semiconductor heterostructure under an in-plane magnetic field.
We observe two gate-driven inversions of the diode polarity in the vicinity of zero field, as well as a third-harmonic component in the dependence of the diode efficiency on the in-plane field angle.
We analyze the Lifshitz invariant for an arbitrary spin–orbit coupling and show that multiple polarity inversions are possible in the presence of both linear and cubic Dresselhaus terms, where the Rashba parameter varies monotonically with gate voltage.
Numerical calculations of the diode efficiency further reveal the presence of higher harmonics in its field-angle dependence in the presence of spin–orbit coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Chiral interactions between tropocollagen molecules determine the collagen microfibril structure
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-01 20:00 EDT
Art’om Zolotarjov, Roland Kröger, Dmitri O. Pushkin
Collagen is the most abundant structural protein in animals, forming hierarchically organised fibrils that provide mechanical support to tissues. Despite detailed structural studies, the physical principles that govern the formation of the characteristic axially-periodic collagen microfibril remain poorly understood. Here, we present a theoretical framework that links the amino acid sequence of tropocollagen to its supramolecular organisation. By combining statistical modeling of residue geometry with sequence-informed interaction potentials, we show that the chiral arrangement of outward-facing residues induces directional intermolecular interactions that drive molecular supercoiling. These interactions favour the formation of right-handed, pentameric microfibrils with a staggered axial periodicity of approximately 67 nm. Our simulations reveal that this structure emerges across a wide range of mammalian collagen sequences as a global energy minimum robust to biochemical noise. These findings provide a mechanistic explanation for collagen’s supramolecular chirality and offer design principles for engineering synthetic collagen-mimetic materials.
Soft Condensed Matter (cond-mat.soft), Biomolecules (q-bio.BM)
27 pages, 9 figures, 3 tables
Monolayer C$_{60}$ networks: A first-principles perspective
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Monolayer fullerene (C$ _{60}$ ) networks combine molecular-level rigidity with crystalline connectivity, offering a promising platform for numerous applications. In this Feature article, we review the physical and chemical properties of fullerene monolayers, focusing on first-principles studies. We first explore the structural stability of monolayer phases and investigate their thermal expansion behaviours. We then outline criteria for photocatalytic water splitting and introduce theoretical predictions which are supported by recent experimental verification. Finally, we show how interlayer stacking, molecular size, and dimensional tuning (from 2D monolayers into 3D crystals, 1D chains, or nanoribbons) offer versatile approaches to modulate their chemical functionality. Together, these insights establish fullerene networks as a novel class of carbon-based materials with tailored properties for catalysis, photovoltaics, and flexible electronics.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Applied Physics (physics.app-ph), Atomic and Molecular Clusters (physics.atm-clus), Chemical Physics (physics.chem-ph)
18 pages, 17 figures
Investigation of magnon behavior in YIG film under microwave excitation using Brillouin light scattering
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Guofu Xu, Kang An, Wenjun Ma, Xiling Li, C. K. Ong, Chi Zhang, Guozhi Chai
We utilize conventional wave-vector-resolved Brillouin light scattering technology to investigate the spin wave response in YIG thin films under high-power microwave excitation. By varying the microwave frequency, external bias magnetic field, and in-plane wave vector, in addition to observing the dipole-exchange spin waves excited by parallel parametric pumping, we further observe broadband spin wave excitation within the dipole-exchange spin wave spectrum. This broadband excitation results from the combined effects of parallel and perpendicular parametric pumping, induced by irregularities in the excitation geometry, as well as magnon-magnon scattering arising from the absence of certain spin wave modes. Our findings offer new insights into the mechanisms of energy dissipation and relaxation processes caused by spin wave excitation in magnetic devices operating at high power.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Towards a $\cos(2φ)$ Josephson element using aluminum junctions with well-transmitted channels
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
J. Griesmar, H. Riechert, M. Hantute, A. Peugeot, S. Annabi, Ç. Ö. Girit, G. O. Steffensen, A. L. Yeyati, E. Arrighi, L. Bretheau, J.-D. Pillet
We introduce a novel method for fabricating all-aluminum Josephson junctions with highly transmitted conduction channels. Such properties are typically associated with structures requiring intricate fabrication processes, such as atomic contacts or hybrid junctions based on semiconducting nanowires and 2D materials. In contrast, our approach relies solely on standard nanofabrication techniques. The resulting devices exhibit a key signature of high-transmission junctions - Multiple Andreev Reflections (MAR) - in their current-voltage characteristics. Furthermore, we propose a straightforward superconducting circuit design based on these junctions, enabling the implementation of a parity-protected qubit.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
8 pages, 6 figures
Topological classification and edge states of magnons in honeycomb ferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Youwen wang, Qiutong Wang, Qingjun Tong, Ci Li
We study the topological classification and related edge states of magnons in ferromagnets on honeycomb that can be described by a class of single-particle bosonic Bogoliubov-de Gennes (BdG) models. Both single layer and bilayer situations are considered. The calculations show that the existence and related topologies of these edge states are well captured by a class of non-Hermitian single or coupled Su-Schrieffer-Heeger chains models H(ky) parameterized by momentum ky, where the edge states can appear as the ground state for some cases. Interestingly, although the eigenproblem of bosonic BdG models is equivalent to the one of non-Hermitian systems, the conventional bulkedge correspondence for Hermitian systems is partially valid. The influence of Dzyaloshinskii-Moriya interactions between next nearest-neighbor spins are also discussed, which break the time-reversal symmetry and lead to a straight connection between edge states for magnonic systems and non-zero Chern number of non-Hermitian bulk two-dimensional systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
17 pages, 10 figures
Universal Bound States with Bose-Fermi Duality in Microwave-Shielded Polar Molecules
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-01 20:00 EDT
Tingting Shi, Haitian Wang, Xiaoling Cui
We investigate universal few-body bound states in microwave-shielded ultracold polar molecules. Under a highly elliptic microwave field, few-molecule scatterings in three dimension are shown to be governed by effective one-dimensional (1D) models. These models well reproduce the tetratomic (two-molecule) bound state and the Born-Oppenheimer potential in three-molecule sector. For hexatomic systems comprising three identical molecules, we find the lowest bound state emerge concurrently with tetratomic state, with binding energy exceeding twice of the latter. Strikingly, all these bound states display Bose-Fermi duality, i.e., they share identical energies and spatial densities in both bosonic and fermionic molecular systems. Universal features of these bound states are supported by the 1D nature of effective scattering and a large repulsive core in the reduced effective potential. For large molecule ensembles, our results suggest the formation of elongated self-bound droplets with crystalline patterns in both bosonic and fermionic polar molecules.
Quantum Gases (cond-mat.quant-gas)
6 pages, 5 figures
Hierarchy of pairing in imbalanced three-component one-dimensional Fermi gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-01 20:00 EDT
Buğra Tüzemen, Tomasz Sowiński
We study a one-dimensional, three-component Fermi gas with population imbalance using the Bogoliubov-de Gennes mean-field approach. We specifically consider pairing in two channels while deliberately excluding the third by setting its interaction strength to zero. By systematically varying the interaction strength and population imbalance, we identify a rich set of spatially modulated superfluid states, including structures akin to the Larkin-Ovchinnikov phase and phase-separated domains. A clear hierarchy emerges in the pairing behavior, shaped by the competition between the local density of states and the Fermi momentum mismatch. A fidelity-based analysis of the density further distinguishes smooth crossovers from sharp spatial reorganizations. Our results shed light on how pairing symmetry and population imbalance determine the structure of spatially inhomogeneous superfluid phases in multicomponent systems with reduced dimensionality.
Quantum Gases (cond-mat.quant-gas)
On persistent energy currents at equilibrium in non-reciprocal systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
We investigate the properties of the mean Poynting vector in global thermal equilibrium, which can be non-zero in non-reciprocal electromagnetic systems. Using dyadic Green’s functions and the fluctuation-dissipation theorem, we provide a general proof that the mean Poynting vector is divergence-free under equilibrium conditions. Relying on this proof, we explicitly demonstrate that for systems where a normal mode expansion of the Green’s function is applicable, the divergence of the equilibrium mean Poynting vector vanishes. As concrete examples, we also examine the equilibrium mean Poynting vector near a planar non-reciprocal substrate and in configurations involving an arbitrary number of dipolar non-reciprocal objects in free space. Finally, we argue that the so-called persistent heat current, while present in equilibrium, cannot be detected through out-of-equilibrium heat transfer measurements.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Optimizing carrier balance in CsPbBr3 nanocrystal LEDs: The role of alkyl ligands and polar electron transport layers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Roshini Jayabalan, Girish K. Hanumantharaju, Theresa Hettiger, Arup Sarkar, Fengshuo Zu, Aladin Ullrich, Norbert Koch, Denis Andrienko, Marcus Scheele, Wolfgang Brütting
The study of lead halide perovskite nanocrystal based light-emitting diodes (LEDs) has advanced significantly, with notable improvements in stability and optical properties. However, optimizing charge carrier injection and transport remains a challenge. Efficient electroluminescence requires a balanced transport of both holes and electrons within the emitting material. Here, we investigate cubic CsPbBr\textsubscript{3} nanocrystals passivated with oleylamine and oleic acid, comparing them to ligand-exchanged nanocrystals with didodecyldimethylammonium bromide (DDABr). Nuclear magnetic resonance spectroscopy and transmission electron microscopy confirm successful ligand exchange, revealing reduced ligand coverage in DDABr-treated nanocrystals. Photoelectron spectroscopy, spectroelectrochemistry, and single-carrier devices indicate improved hole injection in DDABr-capped nanocrystals. Density functional theory calculations further reveal the influence of ligand type and coverage on energy levels, with oleic acid introducing localized states in native nanocrystals. Additionally, incorporation of a polar electron transport layer (ETL) enhances LED performance by over an order of magnitude in DDABr-capped nanocrystals, driven by improved charge balance arising from the spontaneous orientation polarization (SOP) of the ETL. These findings highlight the critical role of ligand selection, passivation degree, and charge transport control by the adjacent organic transport layers in optimizing LED efficiency.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
43 pages (including SI)
Theoretical modeling of synergistic effect of pores and grains on transmittance in transparent piezoelectric ceramics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Zixiang Xiong, Jian Zhu, Xueqian Geng, Zheng Wen, Yongcheng Zhang, Jianyi Liu
Transparent piezoelectric ceramics (TPCs) have great application potential in electro-optical-mechanical multi-functional devices. Preparing high-performance TPCs, especially improving the transparency through microstructure regulation, has recently caused extensive discussion. However, there is still controversy about the influence of grains and pores on the transmittance of ceramics, and there is arbitrariness in the estimation of the theoretical transmittance limit. In this paper, taking PMN-PT-based ceramics as an example, theoretical mechanisms for the transmittance are discussed. An inhomogeneous reflection model is derived to improve the theoretical limit of transmittance. The effects of pores and grains scattering on transmittance are investigated. Rayleigh and RGD approximation are discussed to reveal the underlying scattering mechanisms. It is found that Rayleigh approximation is suitable for describing pore scattering, while RGD approximation is suitable for grain scattering. Thus, a Rayleigh-RGD combined model is proposed to describe light scattering in TPCs and successfully employed to fit experimentally measured transmittance curves.
Materials Science (cond-mat.mtrl-sci)
Fermionic Band Dispersions and an Evidence of Cooperon Excitations in a Spin-$1/2$ Trimer Chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-01 20:00 EDT
P. Srikanth Patnaik, Snehasish Sen, A. K. Bera, Sudhansu S. Mandal, Anushree Roy, S.M. Yusuf
We obtain the solution of the Hamiltonian of an antiferromagnetically coupled spin-$ 1/2$ trimer chain in terms of three bands that host three different species of fermions. While the lowest two bands correspond to spin-$ 1/2$ fermions, the fermions in the highest band are of spin-$ 3/2$ . Because the bands are for different species of fermions, the particle-hole excitation channel across the bands is closed. However, fractionalized excitations as spin-$ 1/2$ and spin-$ 3/2$ fermions in pairs open a cooperon channel of excitations in Raman scattering. The background spectral intensity profile obtained by Raman scattering measurements in Na$ _2$ Cu$ _3$ Ge$ _4$ O$ _{12}$ having a trimer chain consisting of spin-$ 1/2$ Cu ions, has comprehensively been shown to be consistent with these excitations.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 9 figures, 1 table
Superconductivity and trimers on attractive-$U$ Hubbard ladders
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-01 20:00 EDT
We investigate the interplay between superconducting correlations and trimer formation in polarized two-component Fermi gases confined to multileg attractive-$ U$ Hubbard ladders. Employing density matrix renormalization group (DMRG) simulations, we explore the effects of spin-dependent tunneling amplitudes on these systems. Specifically, we analyze how bound states of three fermions (trimers) impact Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superconducting correlations at commensurate charge carrier densities, where $ 2n_{\uparrow} = n_{\downarrow}$ . In one-dimensional (1D) systems, trimer formation is known to suppress FFLO correlations exponentially. Our results demonstrate that this suppression persists on ladder lattices of small width, effectively mirroring the 1D behavior. However, we find a striking departure from the 1D regime as the ladder width increases. On ladders with a width of four legs, the influence of trimers on superconducting correlations becomes negligible, suggesting that wider ladder systems provide a distinct environment where FFLO-like pairing remains robust even in the presence of trimer states. These findings underscore the dimensional crossover in Hubbard systems and shed light on the mechanisms governing superconductivity and bound-state formation in strongly correlated fermionic systems. Our work has implications for understanding unconventional superconductivity in strongly correlated systems.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
16 pages, presented on PCT 2025 Conference, to be published in Communications in Computer and Information Science
Universal scaling law for quantum droplet formation
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-01 20:00 EDT
Given the right set of circumstances, ultracold quantum gases are able to change character and condense into a liquid state of quantum droplets. The size distribution of the droplets is determined dynamically in the condensation process. A semi-quantitative argument is presented which suggests that, at zero temperature, a multiple droplet system has is a preferred scale $ \propto v^{-d}$ , with $ d\approx 0.5$ , where $ v$ is the rate of change of parameters at the time of droplet formation. Numerical simulations of two dimensional systems strongly support a power law, but with an exponent $ d\in(0.3,0.4)$ .
Quantum Gases (cond-mat.quant-gas)
5 pages, 3 figures
Pressure and strain effects on the $\textit{ab initio}$ $GW$ electronic structure of La$_3$Ni$_2$O$_7$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-01 20:00 EDT
Jean-Baptiste de Vaulx, Quintin N. Meier, Pierre Toulemonde, Andrés Cano, Valerio Olevano
The recent discovery of superconductivity in La$ _3$ Ni$ _2$ O$ _7$ at a critical temperature above 80~K points to a non-conventional pairing mechanism in nickelates as in cuprates, possibly due to electronic correlations. We have calculated from first principles the electronic structure of La$ _3$ Ni$ 2$ O$ 7$ under the effect of pressure and epitaxial strain including correlations by the $ GW$ approximation to the many-body self-energy. We find that the Fermi surface is composed of a characteristic cuprate-shape sheet $ \beta$ plus a nickelate-specific cylinder $ \alpha$ , both from Ni $ e_g$ orbitals, with a non-negligible drop in the quasiparticle weight and an effective 1D character. This topology results from a delicate balance between the Ni-3$ d{z^2}$ hole pocket $ \gamma$ , which is suppressed by correlations, and an emerging La-5$ d{x^2-y^2}$ electron pocket induced by both correlation and pressure/strain effects and whose role at low energy has been neglected so far. Unlike cuprates, the electronic structure of La$ _3$ Ni$ _2$ O$ _7$ is already correctly described from ab initio and in agreement with the experiment without the need to introduce Hubbard $ U$ adjustable parameters or to invoke a strongly correlated physics.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
19 pages, 18 figures 2 tables
Effect of Magnetic Anisotropy and Gradient-Induced Dzyaloshinskii-Moriya Interaction on the Formation of Magnetic Skyrmions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Adam Erickson, Qihan Zhang, Hamed Vakili, Edward Schwartz, Suvechhya Lamichhane, Chaozhong Li, Boyu Li, Dongsheng Song, Guozhi Chai, Sy-Hwang Liou, Alexey A. Kovalev, Jingsheng Chen, Abdelghani Laraoui
Topological spin textures (e.g. skyrmions) can be stabilized by interfacial Dzyaloshinskii-Moriya interaction (DMI) in the magnetic multilayer, which has been intensively studied. Recently, Bloch-type magnetic skyrmions stabilized by composition gradient-induced DMI (g-DMI) have been observed in 10-nm thick CoPt single layer. However, magnetic anisotropy in gradient-composition engineered CoPt (g-CoPt) films is highly sensitive to both the relative Co/Pt composition and the film thickness, leading to a complex interplay with g-DMI. The stability of skyrmions under the combined influence of magnetic anisotropy and g-DMI is crucial yet remains poorly understood. Here, we conduct a systematic study on the characteristics of magnetic skyrmions as a function of gradient polarity and effective gradient strength (defined as gradient/thickness) in g-CoPt single layers (thickness of 10-30 nm) using magnetic force microscopy (MFM), bulk magnetometry, and topological Hall effect measurements. Brillouin light scattering confirms that both the sign and magnitude of g-DMI depend on the polarity and amplitude of the composition gradient in g-CoPt films. MFM reveals that skyrmion size and density vary with g-CoPt film thickness, gradient polarity, and applied magnetic field. An increased skyrmion density is observed in samples exhibiting higher magnetic anisotropy, in agreement with micromagnetic simulations and energy barrier calculations.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Landau-Zener-Stückelberg spectroscopy of a fluxonium quantum circuit
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Valentín Reparaz, María José Sánchez, Maximiliano Gatto, Daniel Dominguez, Leandro Tosi
In this work, we study the time-averaged populations obtained for a fluxonium circuit under a large amplitude nonresonant periodic drive. We present numerical simulations of the time evolution which consider the multi-level structure of the driven quantum circuit, looking for a realistic modeling closer to experimental implementations. The Landau-Zener-Stückelberg spectra show resonances that can be understood as originated from constructive interference favoring transitions to higher levels. For a truncated two-level system (TLS) the resonance patterns can be interpreted using a simplified description of the avoided crossing that takes into account the dynamic phase accumulated at each operation point. For the multilevel case, we derive an effective two-level Hamiltonian using a Schrieffer-Wolff transformation starting from the Floquet Hamiltonian in the Sambe space. Our study provides predictive insight into experimental outcomes, offering an intuitive interpretation that could also support the implementation of fast-non-adiabatic single-qubit gates and entangling protocols.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
14 pages, 9 figures
Characterization and optimization of heat engines: Pareto-optimal fronts and universal features
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-01 20:00 EDT
Gustavo A. L. Forão, Jonas Berx, Carlos E. Fiore
Characterizing and optimizing nanoscopic heat engines require an appropriate understanding of the interplay between power, efficiency, entropy production and fluctuations. Despite significant recent advancements, including linear stochastic thermodynamics and thermodynamic uncertainty relations (TURs), a complete scenario remains elusive. In this work, we give a further step by showing that, under certain common and general conditions, the heat engine regime can be characterized by the minima of power fluctuations and entropy production, which together delimit its optimal performance, achieved when these conditions are fully satisfied. Conversely, when these conditions are not strictly met, the occurrence of the minimum still approximately describes the system, suggesting a broader range of applicability. Contrasting with most of studies in which the system optimization is carried out solely taking into account the power and efficiency, we introduce a multi-objective optimization framework based on Pareto fronts, also considering the role of fluctuation and dissipation. Our results reveal a general trend: while simultaneous optimization over a few parameters typically yields convex Pareto fronts, these fronts become concave as more parameters are varied freely and non-conservative driving becomes significant. Illustrating our findings, we consider simple two and three state systems as well as richer collective systems, exhibiting novel aspects of optimizations and protocol phase transitions.
Statistical Mechanics (cond-mat.stat-mech)
9 pages, 5 figures
The role of terminal groups in non-chiral rod-like compounds on the formation of polar fluids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Michał Czerwiński, Mateusz Mrukiewicz, Mateusz Filipow, Damian Pociecha, Natalia Podoliak, Dalibor Repcek, Monika Zając, Dorota Węgłowska
The emergence of ferroelectric mesophases in non-chiral liquid crystal (LCs) has sparked fundamental interest in the molecular mechanisms governing polarity. In this study, we investigate how terminal molecular groups influence the formation and stability of polar phases by analyzing six compounds from three homologous series. Specifically, we compare newly synthesized homologs with a nitro group, which predominantly exhibit polar mesophases, to previously reported structurally related analogs containing either a cyano group or a fluorine atom as terminal fragment. Density Functional Theory (DFT) calculations provide insights into electronic surface potential (ESP) distributions, revealing alternating regions of positive and negative charge density along the molecular axis, consistent with Madhusudana model of polar phase stabilization. We propose the ESP-derived parameter quantifying terminal electrostatic charge, revealing a direct correlation between the negative to positive charge ratio at the molecular termini and the formation of ferroelectric or antiferroelectric mesophases. To validate this hypothesis, we analyze the molecular structure-mesomorphic behavior relationship of other known non-chiral compounds that exhibit polar phases, demonstrating the critical role of terminal groups in determining mesophase polarity. Our findings enhance the understanding of the molecular origins of ferroelectricity in non-chiral LCs, paving the way for the rational design of next-generation functional polar soft materials.
Materials Science (cond-mat.mtrl-sci)
Observation of Intrinsic and LED Light-Enhanced Memristor Performance in In-Plane Ferroelectric NbOI2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Zheng Hao, Gaolei Zhao, Haoran Li, Jizhang Zhang, Jiabin Liu, Fanyi Kong, Konstantin Kozadaev, Yongjiang Li, Xue Han, Hong Li, Huolin Huang, Changsen Sun, Alexei Tolstik, Andrey Novitsky, Lujun Pan, Dawei Li
Two-dimensional (2D) layered ferroelectrics, as an emerging area of research, have attracted extensive attention, while memristors based on new 2D ferroelectric materials have yet to be fully explored, thereby limiting their applications in modern nanoelectronics. In this work, we report the observation of intrinsic memristive behavior in a newly discovered 2D in-plane ferroelectric material, NbOI2, and the giant enhancement of the memristive performance using LED visible light. The results show that NbOI2 exhibits intrinsically strong memristive response with a current on/off ratio of up to 10^4 and stable switching cycles, which is independent of back-gate voltage. Under LED visible light illumination, the current on/off ratio in NbOI2 is over one order of magnitude higher than that without light, meanwhile, the coercive field is significantly reduced to less than 1.22 kVcm-1, much lower than other 2D ferroelectric material-based memristors. Interestingly, both the intrinsic and the light-enhanced resistive switching phenomena only occur along the in-plane b-axis direction, indicating that the memristive behavior in NbOI2 is driven by electric field-induced and optical field-enhanced ferroelectric polarization switching mechanisms, as evidenced by a combined orientation-dependent electrical/optoelectrical measurement and sweep cycle-induced structural evolution analysis. Our study not only provides a materials strategy based on new 2D ferroelectrics for designing memristor applications, but also offers a simple optical method to enhance its performance, paving the path for its implementation in novel nanoelectronics and optoelectronics.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
20 pages, 5 figures
Boundary effects in classical liquid density fluctuations at finite temperature
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-01 20:00 EDT
Herondy Mota, K. E. L. de Farias
We investigate thermal effects on density fluctuations in confined classical liquids using phonon quantization. The system is modeled via a massless scalar field between perfectly reflecting parallel planes with Dirichlet, Neumann, and mixed boundary conditions. Exact closed-form expressions are derived for the mean square mass density, total energy density, and thermodynamic quantities including Helmholtz free energy and entropy densities. Our analysis identifies distinct regimes, namely, a low-temperature quantum regime exhibiting characteristic power-law behavior for each boundary condition, and a high-temperature classical regime where $ \hbar$ -independent behavior emerges as expected. A particularly interesting finding shows that while most quantities transition naturally to classical behavior, the mean square density fluctuation requires explicit consideration of the $ \hbar\to 0$ limit. The entropy density vanishes at zero temperature, in agreement with the Nernst heat theorem. Numerical analysis confirms our analytical results, particularly the asymptotic temperature behaviors and the intermediate crossover region, in which quantum and classical effects compete. This regime is governed by the energy scale $ k_B T \sim \hbar u / a$ , where $ a$ is the distance between the planes and $ u$ is the sound velocity.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
17 pages, 8 Figures, 1 Table
Improved Lanczos Algorithm using Matrix Product States
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-01 20:00 EDT
Yu Wang, Zhangyu Yang, Christian B. Mendl
We improve the Lanczos algorithm using the matrix product state representation proposed in Phys. Rev. B 85, 205119 (2012). As an alternative to the density matrix renormalization group (DMRG), the Lanczos algorithm avoids local minima and can directly find multiple low-lying eigenstates. However, its performance and accuracy are affected by the truncation required to maintain the efficiency of the tensor network representation. In this work, we enhance its convergence by restarting with multiple states. We benchmark our method on one-dimensional instances of the Fermi-Hubbard model with 8 sites and the Heisenberg model with 16 sites in an external field, using numerical experiments targeting the first five lowest eigenstates. Across these tests, our approach obtains accuracy improvements of three to seven orders of magnitude. Finally, we extend the Heisenberg model simulation to a lattice with 30 sites to highlight its scalability.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
Vortex flow anisotropy in nematic superconductors
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-01 20:00 EDT
F. Castillo Menegotto, R. S. Severino, P. D. Mininni, E. Fradkin, V. Bekeris, G. Pasquini, G. S. Lozano
We investigate the vortex flow anisotropy in the mixed state of nematic superconductors, focusing on the effects of nematic-superconducting coupling on vortex dynamics. Using numerical simulations within a time-dependent Ginzburg-Landau (TDGL) approach, we analyze vortex viscosity in a model featuring an s-wave superconducting order parameter coupled to an Ising-like nematic order parameter, suitable for systems with $ C_4$ symmetry. Our results indicate that nematicity induces a significant anisotropy in the flux-flow resistivity, which depends on both vortex core shape anisotropy and normal-phase conductivity anisotropy. These two effects can either compete or cooperate with each other. We discuss the implications of these findings for identifying nematic superconductivity in the superconducting phase. Our work provides new insights into the interplay between nematic and superconducting order parameters, leading to new possibilities for experimental and theoretical exploration of anisotropic transport properties in unconventional superconductors.
Superconductivity (cond-mat.supr-con)
Anomalous Josephson effect in hybrid superconductor-hole systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-01 20:00 EDT
Peter D. Johannsen, Henry F. Legg, Stefano Bosco, Daniel Loss, Jelena Klinovaja
We consider hybrid systems consisting of a hole-doped semiconductor coupled to electronic states of finite-size superconductors, where the opposite sign of the masses in the two subsystems give rise to insulating gaps at subband anticrossings. Consequently, increasing the coupling strength to the superconductor can paradoxically suppress the proximity-induced superconductivity in the semiconductor by enhancing these insulating gaps. We demonstrate that the presence of such induced insulating gaps leads to a characteristic anomalous behavior of the critical supercurrent in Josephson junctions based on these hybrid structures. Our findings provide important insights for the design of robust quantum computing platforms utilizing hybrid superconductor-hole systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
6 pages, 3 figures
Two lock-in amplifiers based $3ω$ technique: a practical guide for thermal conductivity experiments in bulk samples
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-01 20:00 EDT
Alexandre Henriques, Murilo Santoma, Steffen Wirth, Julio Larrea Jiménez, Valentina Martelli
The accurate determination of thermal conductivity $ \kappa(T)$ in bulk materials is essential to assess their performance as candidates for specific applications. The 3$ \omega$ technique is an established methodology for studying the thermal conductivity of thin films and becomes particularly suitable in the case of bulk specimens at room temperature and above, where standard stationary techniques require significant corrections for radiative losses. Although this method has been employed in several works, it remains not widely adopted because its implementation demands considerable sophistication, including experiment design, thin film deposition techniques and choices of the geometry of the current/heat transducer, electronics, and analytical treatment of the signals. This work reviews the technique’s most crucial technical aspects, providing practical support for a quick and user-friendly implementation, from the design phase to the execution and analysis. We release a Python-based graphical user interface that supports a quick quantitative estimation of the investigated temperature profiles based on the geometrical parameters (width/length) of the deposited transducer (heater/thermometer metal line) before an experiment, guaranteeing an optimal engineering of the experimental conditions for each given material under scrutiny.
Materials Science (cond-mat.mtrl-sci), Instrumentation and Detectors (physics.ins-det)
Comment on ‘Anomalies in the Electronic Stopping of Slow Antiprotons in LiF’, arXiv:2501.14381
New Submission | Other Condensed Matter (cond-mat.other) | 2025-05-01 20:00 EDT
This work contains detailed discussions on the contents of Phys. Rev. Lett. 134, 076401 (2025), in the following denoted PRL134. In this comment, we revisit and elaborate on the Adiabatic Ionization Model (AIM) for the energy loss of antiparticles in matter, with particular reference to its theoretical foundation as established previously. The AIM framework plays a central role in describing the ionization dynamics in the low-velocity regime considered by the authors of PRL134. Calculated AIM results for the energy loss of antiprotons in LiF crystals are compared to experimental data and different other models, pointing to severe problems of the PRL134 results.
Beyond this specific comparative theoretical investigation, we critically examine several statements and assumptions made in PRL134. Certain claims presented therein appear to be inconsistent with established theoretical principles or are insufficiently justified by the data and arguments provided. As such, we believe that further clarification, and in some cases, a more rigorous justification, is necessary to substantiate those points.
Other Condensed Matter (cond-mat.other), Atomic Physics (physics.atom-ph)
8 pages, 5 figures, Comment on arXiv:2501.14381