CMP Journal 2025-01-23
Statistics
Nature Nanotechnology: 1
Nature Physics: 1
Physical Review Letters: 14
Physical Review X: 1
arXiv: 54
Nature Nanotechnology
Salt-in-presalt electrolyte solutions for high-potential non-aqueous sodium metal batteries
Original Paper | Batteries | 2025-01-22 19:00 EST
Ai-Min Li, Peter Y. Zavalij, Fred Omenya, Xiaolin Li, Chunsheng Wang
Room-temperature non-aqueous sodium metal batteries are viable candidates for cost-effective and safe electrochemical energy storage. However, they show low specific energy and poor cycle life as the use of conventional organic-based non-aqueous electrolyte solutions enables the formation of interphases that cannot prevent degradations at the positive and negative electrodes. Here, to promote the formation of inorganic NaF-rich interphases on both negative and positive electrodes, we propose the salt-in-presalt (SIPS) electrolyte formulation strategy. In SIPS, sodium bis(fluorosulfonyl)imide (NaFSI) salt is dissolved in the liquid precursor of the sodium bis(trifluoromethylsulfonyl)imide (NaTFSI) salt, that is, N,N-dimethyltrifluoromethane-sulfonamide, called PreTFSI. The prepared 0.5 M NaFSI in PreTFSI (SIPS5) electrolyte solution shows an electrochemical stability up to 6.7 V versus Na|Na+ and enables a Na stripping/plating average Coulombic efficiency of 99.7% at 2.0 mA cm-2 and 4.0 mAh cm-2 in Na||Al cell configuration. By testing SIPS5 in Na metal and ‘anode-less' coin and pouch cell configurations using NaNi0.6Mn0.2Co0.2O2 or sulfurized polyacrylonitrile as positive electrode active materials, we demonstrate the ability of the SIPS strategy to deliver improved specific discharge capacity and capacity retentions at high cell potentials and moderate applied specific currents for cell cycle life up to 1,000 cycles.
Batteries, Electrochemistry, Materials for energy and catalysis
Nature Physics
Time-hidden magnetic order in a multi-orbital Mott insulator
Original Paper | Magnetic properties and materials | 2025-01-22 19:00 EST
Xinwei Li, Iliya Esin, Youngjoon Han, Yincheng Liu, Hengdi Zhao, Honglie Ning, Cora Barrett, Jun-Yi Shan, Kyle Seyler, Gang Cao, Gil Refael, David Hsieh
Photo-excited quantum materials can be driven into thermally inaccessible metastable states that exhibit structural, charge, spin, topological and superconducting orders. Metastable states typically emerge on timescales set by the intrinsic electronic and phononic energy scales, ranging from femtoseconds to picoseconds, and can persist for weeks. Therefore, studies have primarily focused on ultrafast or quasi-static limits, leaving the intermediate time window less explored. Here we reveal a metastable state with broken glide-plane symmetry in photo-doped Ca2RuO4 using time-resolved optical second-harmonic generation and birefringence measurements. We find that the metastable state appears long after intralayer antiferromagnetic order has melted and photo-carriers have recombined. Its properties are distinct from all known states in the equilibrium phase diagram and are consistent with intralayer ferromagnetic order. Furthermore, model Hamiltonian calculations reveal that a non-thermal trajectory to this state can be accessed via photo-doping. Our results expand the search space for out-of-equilibrium electronic matter to metastable states emerging at intermediate timescales.
Magnetic properties and materials, Nonlinear optics, Phase transitions and critical phenomena, Ultrafast photonics
Physical Review Letters
Universal Work Statistics in Long-Range Interacting Quantum Systems
Research article | Long-range interactions | 2025-01-23 05:00 EST
Andrea Solfanelli and Nicolò Defenu
We determine the conditions under which the presence of long-range interactions reduce the energy losses due to defect generation during nonadiabatic evolution, crucial for enhancing the power to efficiency ratio of quantum thermal devices. In order to do so, we investigate the response of long-range systems to diverse external drivings, emphasizing their robustness against dynamic excitation in comparison to generic local systems. This phenomenon is demonstrated through the study of the quantum work statistics, revealing insights into energy transfer efficiency and dynamical quantum criticality. Our results demonstrate the benefits of including a long-range interacting medium for quantum thermodynamics application, highlighting the potential to optimize finite-time quantum thermal cycles. Thanks to the effective dimension approach our findings can be drawn in full generality and, then, specified to different experimentally relevant scenarios.
Phys. Rev. Lett. 134, 030402 (2025)
Long-range interactions, Nonequilibrium & irreversible thermodynamics, Nonequilibrium statistical mechanics, Quantum phase transitions, Quantum quench, Quantum thermodynamics, Nonequilibrium lattice models, Quantum many-body systems, Quantum spin models, Large deviation & rare event statistics, Renormalization group
Path Percolation in Quantum Communication Networks
Research article | Complex systems | 2025-01-23 05:00 EST
Xiangyi Meng, Bingjie Hao, Balázs Ráth, and István A. Kovács
In a quantum communication network, links represent entanglement between qubits located at different nodes. Even if two nodes are not directly linked by shared entanglement, they can still communicate via routing protocols. However, in contrast to classical communication, each quantum communication event removes all participating links along the routed path, disrupting the quantum communication network. Here, we propose a simple model, where randomly selected pairs of nodes communicate through the shortest paths. Each time such a path is used, all participating links are eliminated, leading to a correlated percolation process that we call ''path percolation.'' We study path percolation both numerically and analytically and present the phase diagram of the steady states as a function of the rate at which new links are being added to the network. As a key result, the steady state is found to be independent of the initial network topologies when new links are added randomly between disconnected components. We close by discussing extensions of path percolation and link replenishment, along with their potential applications.
Phys. Rev. Lett. 134, 030803 (2025)
Complex systems, Percolation phase transition, Quantum communication, Quantum networks, Communication networks, Tree network, Network Models, Percolation theory
Testing Mirror Symmetry in the Universe with LIGO-Virgo Black-Hole Mergers
Research article | Cosmology | 2025-01-23 05:00 EST
Juan Calderón Bustillo, Adrian del Rio, Nicolas Sanchis-Gual, Koustav Chandra, and Samson H. W. Leong
Certain precessing black-hole mergers produce gravitational waves with net circular polarization, understood as an imbalance between right- and left-handed amplitudes. According to the cosmological principle, such emission must average to zero across all binary mergers in our Universe to preserve mirror-reflection symmetry at very large scales. We present a new independent gravitational-wave test of this hypothesis. Using a novel observable based on the Chern-Pontryagin pseudoscalar, we measure the emission of net circular polarization across 47 black-hole mergers recently analyzed by [T. Islam et al., arXiv:2309.14473.] with a state-of-the art model for precessing black-hole mergers in general relativity. The average value obtained is consistent with zero. Remarkably, however, we find that at least 82% of the analyzed sources must have produced net circular polarization. Of these, GW200129 shows strong evidence for mirror asymmetry, with a Bayes factor of 12.6 or, equivalently, 93.1% probability. We obtain consistent (although stronger) results of 97.5% and 94.3%, respectively, using public results on this event from [M. Hannam et al., Nature (London) 610, 652 (2022).] and performing our own parameter inference. This finding further implies evidence of astrophysical sources that can spontaneously emit circularly polarized photons by quantum effects. Forthcoming black-hole merger detections will enable stronger constraints on large-scale mirror asymmetry and the cosmological principle.
Phys. Rev. Lett. 134, 031402 (2025)
Cosmology, General relativity, Gravitational waves
Experimental Evidence for Double Intermolecular Coulombic Decay in Bio-Relevant Molecular Dimers
Research article | Electronic excitation & ionization | 2025-01-23 05:00 EST
Xintai Hao, Xiaorui Xue, Jiaqi Zhou, Xinyu Zhang, Xiaokai Li, Qingrui Zeng, Qibo Ma, Yongtao Zhao, Chuncheng Wang, Sizuo Luo, Dajun Ding, and Xueguang Ren
We report the experimental observation of double intermolecular Coulombic decay (dICD) and reveal its potential for radiation biology in some prototypical molecular dimers consisting of benzene, pyridine, and water. In dICD, the inner-shell vacancy is filled by an electron from an outer shell and the energy released is transferred to doubly ionize the neighboring molecule with the emission of two low-energy electrons. The system further relaxes by a three-body Coulomb explosion process, e.g., \({\mathrm{CH}}_{3}^{+}+{\mathrm{C}}_{5}{\mathrm{H}}_{3}^{+}+{\mathrm{C}}_{6}{\mathrm{H}}_{6}^{+}\) for benzene dimer. Through multicoincidence momentum imaging, we find that dICD is an efficient relaxation pathway for the Auger-accessible inner-shell ionization states in molecular complexes. Moreover, this ultrafast decay mechanism causes a direct breaking of the aromatic rings, which is observed to be a general phenomenon occurring in biological systems and thus can play an important role in radiation biology.
Phys. Rev. Lett. 134, 033001 (2025)
Electronic excitation & ionization, Molecular dissociation
Probing Rotational Decoherence with a Trapped-Ion Planar Rotor
Research article | Open quantum systems & decoherence | 2025-01-23 05:00 EST
Neil Glikin, Benjamin A. Stickler, Ryan Tollefsen, Sara Mouradian, Neha Yadav, Erik Urban, Klaus Hornberger, and Hartmut Häffner
The quantum rotor is one of the simplest model systems in quantum mechanics, but only in recent years has theoretical work revealed general fundamental scaling laws for its decoherence. For example, a superposition of orientations decoheres at a rate proportional to the sine squared of the angle between them. Here, we observe scaling laws for rotational decoherence dynamics for the first time, using a \(4\text{ }\text{ }\mathrm{\mu }\mathrm{m}\) diameter planar rotor composed of two Paul-trapped ions. We prepare the rotational motion of the ion crystal into superpositions of angular momentum with well-defined differences ranging from $1- 3$, and measure the rate of decoherence. We also tune the system-environment interaction strength by introducing resonant electric field noise. The observed scaling relationships for decoherence are in excellent agreement with recent theoretical work, and are directly relevant to the growing development of rotor-based quantum applications.
Phys. Rev. Lett. 134, 033601 (2025)
Open quantum systems & decoherence, Quantum coherence & coherence measures, Rotational states, Trapped ions, Mach-Zehnder atom interferometry
Exogenous--Endogenous Surfactant Interaction Yields Heterogeneous Spreading in Complex Branching Networks
Research article | Lubrication theory | 2025-01-23 05:00 EST
Richard Mcnair, Fernando Temprano-Coleto, François J. Peaudecerf, Frédéric Gibou, Paolo Luzzatto-Fegiz, Oliver E. Jensen, and Julien R. Landel
Experiments have shown that surfactant introduced to a liquid-filled maze can find the solution path. We reveal how the maze-solving dynamics arise from interactions between the added surfactant and endogenous surfactant present at the liquid surface. We simulate the dynamics using a nonlinear model solved with a discrete mimetic scheme on a graph. Endogenous surfactant transforms local spreading into a nonlocal problem with an omniscient view of the maze geometry, key to the maze-solving dynamics. Our results offer insight into surfactant-driven transport in complex networks such as lung airways.
Phys. Rev. Lett. 134, 034001 (2025)
Lubrication theory, Surface tension effects, Thin fluid films, Stokes equations
Pellet Rocket Effect in Magnetic Confinement Fusion Plasmas
Research article | Magnetic confinement fusion | 2025-01-23 05:00 EST
Nico J. Guth, Oskar Vallhagen, Per Helander, Istvan Pusztai, Sarah L. Newton, and Tünde Fülöp
Pellets of frozen material traveling into a magnetically confined fusion plasma are accelerated by the so-called pellet rocket effect. The nonuniform plasma heats the pellet ablation cloud asymmetrically, producing pressure-driven, rocketlike propulsion of the pellet. We present a semianalytical model of this process by perturbing a spherically symmetric ablation model. Predicted pellet accelerations match experimental estimates in current tokamaks (\(\sim {10}^{5}\text{ }\text{ }\mathrm{m}/{\mathrm{s}}^{2}\)). Projections for ITER high-confinement scenarios (\(\sim {10}^{6}\text{ }\text{ }\text{ }\mathrm{m}/{\mathrm{s}}^{2}\)) indicate significantly shorter pellet penetration than expected without this effect, which could limit the effectiveness of disruption mitigation.
Phys. Rev. Lett. 134, 035101 (2025)
Magnetic confinement fusion
Ionic Conductivity in Disordered Media: Molecular Flexibility as a New Paradigm to Enhance Ion Motion in Glassy Electrolytes
Research article | Capacitance | 2025-01-23 05:00 EST
M. Micoulaut
We investigate the role of molecular flexibility on the electrical transport properties of model electrolytes containing ions and an underlying disordered network structure with changing connectedness. Rather than focusing on the effect of ion content in a stoichiometric network former \({\mathrm{AY}}_{2}\) (e.g., \({\mathrm{SiS}}_{2}\)), we explore the possibility of increasing the \(\mathrm{Y}\mathbin: \mathrm{A}\) ratio (flexibility index \(m\)) in order to reduce connectivity and to promote the occurrence of flexible modes and topological degrees of freedom in the network structure. At fixed ion content and below a certain threshold modifier composition \({x}_{c}\), topological constraint counting indicates that a mean-field stress-to-flexible transition is expected for a flexibility index \({m}_{c}\), and an ion hopping model predicts a substantial increase of conductivity once \(m>{m}_{c}\). Molecular dynamics simulations on a typical amorphous electrolyte, \(x{\mathrm{Na}}_{2}\mathrm{S}- (1- x){\mathrm{SiS}}_{m}\), independently and quantitatively confirm the prediction as anomalous changes with \(m\) are obtained, and these manifest by waterlike diffusivity anomalies, and a substantial increase of ionic conductivity upon moderate change of \(m\). The analysis disentangles contributions from mobility and the free carrier rate in the electrical transport, and finally suggests that molecular flexibility can serve as an efficient way for conductivity enhancement in all solid-state batteries using amorphous electrolytes.
Phys. Rev. Lett. 134, 036303 (2025)
Capacitance, Ionic transport, Amorphous materials, Glasses
Quantum Correction to the Orbital Hall Effect
Research article | Hall effect | 2025-01-23 05:00 EST
Hong Liu, James H. Cullen, Daniel P. Arovas, and Dimitrie Culcer
Evaluations of the orbital Hall effect (OHE) have retained only interband matrix elements of the position operator. Here, we evaluate the OHE including all matrix elements of the position operator, including the technically challenging intraband elements. We recover previous results and find quantum corrections due to the noncommutativity of the position and velocity operators and interband matrix elements of the orbital angular momentum. The quantum corrections dominate the OHE responses of the topological antiferromagnet CuMnAs and of massive Dirac fermions.
Phys. Rev. Lett. 134, 036304 (2025)
Hall effect, Spintronics, 2-dimensional systems, Topological materials, Angular momentum, Density matrix methods
Orbital Pumping Incorporating Both Orbital Angular Momentum and Position
Research article | Magnetization dynamics | 2025-01-23 05:00 EST
Seungyun Han, Hye-Won Ko, Jung Hyun Oh, Hyun-Woo Lee, Kyung-Jin Lee, and Kyoung-Whan Kim
We develop a theory of adiabatic orbital pumping, highlighting qualitative differences from spin pumping. An oscillating magnetic field pumps not only orbital angular momentum current, but also orbital angular position current. The latter, which has no spin counterpart, underscores the incompleteness of existing orbital torque theories. Importantly, both types of orbital currents can be detected as transverse electric voltages, which contain considerable second-harmonic components unlike in spin pumping. Moreover, orbital currents can be pumped by lattice dynamics that carry phonon angular momentum, implying that orbital currents can, in turn, induce phonon angular momentum. Our Letter open up new possibilities for generating orbital currents and provides a broader understanding of the interplay between spin, orbital, and phonon dynamics.
Phys. Rev. Lett. 134, 036305 (2025)
Magnetization dynamics, Spin pumping, Spintronics, Angular momentum
Enhanced Strange Metallicity due to Hubbard-\(U\) Coulomb Repulsion
Research article | Dynamical mean field theory | 2025-01-23 05:00 EST
Andrew Hardy, Olivier Parcollet, Antoine Georges, and Aavishkar A. Patel
A model of electrons that has a particular Coulomb repulsion and is coupled to a 2D bosonic bath shows a quantum critical point where traditional Fermi-liquid physics breaks down, resulting in a so-called strange metal.
Phys. Rev. Lett. 134, 036502 (2025)
Dynamical mean field theory, Non-Fermi-liquid theory, Sachdev-Ye-Kitaev model
Glass Transition in Monolayers of Rough Colloidal Ellipsoids
Research article | Glass transition | 2025-01-23 05:00 EST
Jian Liang, Xuan Feng, Ning Zheng, Huaguang Wang, Ran Ni, and Zexin Zhang
Roughing up the surfaces of particles in a colloidal system can smooth its transition into a glassy state.
Phys. Rev. Lett. 134, 038202 (2025)
Glass transition, Colloidal glass, Colloids, Molecular dynamics, Optical microscopy
Biased Ensembles of Pulsating Active Matter
Research article | Collective behavior | 2025-01-23 05:00 EST
William D. Piñeros and Étienne Fodor
Ensembles of particles that actively pulsate in size which are also biased to select certain rare configurations can exhibit complex emergent behaviors that depend on system geometry.
Phys. Rev. Lett. 134, 038301 (2025)
Collective behavior, Dynamical phase transitions, Packing & jamming problems, Living matter & active matter, Large deviation & rare event statistics, Theories of collective dynamics & active matter
High-Speed Combinatorial Polymerization through Kinetic-Trap Encoding
Research article | Nonequilibrium statistical mechanics | 2025-01-23 05:00 EST
Félix Benoist and Pablo Sartori
Like the letters in the alphabet forming words, reusing components of a heterogeneous mixture is an efficient strategy for assembling a large number of target structures. Examples range from synthetic DNA origami to proteins self-assembling into complexes. The standard self-assembly paradigm views target structures as free-energy minima of a mixture. While this is an appealing picture, at high speed structures may be kinetically trapped in local minima, reducing self-assembly accuracy. How then can high speed, high accuracy, and combinatorial usage of components coexist? We propose to reconcile these three concepts not by avoiding kinetic traps, but by exploiting them to encode target structures. This can be achieved by sculpting the kinetic pathways of the mixture, instead of its free-energy landscape. We formalize these ideas in a minimal toy model, for which we analytically estimate the encoding capacity and kinetic characteristics, in agreement with simulations. Our results may be generalized to other soft-matter systems capable of computation, such as liquid mixtures or elastic networks, and pave the way for high-dimensional information processing far from equilibrium.
Phys. Rev. Lett. 134, 038402 (2025)
Nonequilibrium statistical mechanics, Self-assembly
Physical Review X
Time-Resolved X-Ray Spectroscopy from the Atomic Orbital Ground State Up
Research article | Photoinduced effect | 2025-01-23 05:00 EST
Daniel Jost, Eder G. Lomeli, Ta Tang, Joshua J. Kas, John J. Rehr, Wei-Sheng Lee, Hong-Chen Jiang, Brian Moritz, and Thomas P. Devereaux
Simulations of x-ray spectroscopies demonstrate the insights that can be obtained from charge-transfer pumping and how this process affects ground- and excited-state properties.
Phys. Rev. X 15, 011012 (2025)
Photoinduced effect, Strongly correlated systems, Exact diagonalization, Pump-probe spectroscopy, Resonant inelastic x-ray scattering, X-ray absorption spectroscopy
arXiv
How to Measure and Model Light-Induced Spin Transfer
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Sinéad A. Ryan, Mohamed F. Elhanoty, Anya Grafov, Peter C. Johnsen, Na Li, Justin M. Shaw, Anna Delin, Anastasios Markou, Edouard Lesne, Claudia Felser, Olle Eriksson, Erna K. Delczeg-Czirjak, Debjani Karmakar, Henry C. Kapteyn, Oscar Grånäs, Margaret M. Murnane
Femtosecond laser light can transfer spin angular momentum between magnetic subspecies that exhibit hybridized valence bands within an alloy or compound, and represents the fastest route for manipulating the magnetization of a material. To date, ultrafast spin transfer has predominantly been explained in terms of the initial and final states available for laser excitation. Here, by comparing the measured and calculated dynamics across the entire \(M\)-edges of two very similar Heusler compounds, \(Co_2MnGa\) and \(Co_2MnGe\) as well as a sample of elemental Co, we find that simply accounting for the initial and final electron states available for laser excitation cannot alone explain the experimental observations. The influence of spin lifetimes must also be included, due to the shifting of the Fermi level upon replacing Ga with Ge, or the presence of crystalline disorder. This explains why the ordered \(L2_1\) phase of \(Co_2MnGa\) demonstrates strong laser-induced magnetic signal enhancements across the entire Co-edge, while similar enhancements were not observed in partially disordered \(Co_2MnGe\). Although intra-site spin-transfers were expected in the minority channel in pure Co due to the presence of many more available states in the minority channel above the Fermi level, no such signal was observed due to very short few-femtosecond spin lifetimes in a metal. Finally, we identify key regions in the magnetic asymmetry where a transiently enhanced signal could be misinterpreted as a light-induced spin-transfer signature.
Materials Science (cond-mat.mtrl-sci)
Eliashberg Theory and Superfluid Stiffness of Band-Off-Diagonal Pairing in Twisted Graphene
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-23 20:00 EST
Bernhard Putzer, Mathias S. Scheurer
Recently, band-off-diagonal superconductivity has been proposed [Nat. Commun. 14, 7134 (2023)] as a candidate pairing state for twisted graphene systems. Based on mean-field theory, it was shown that it not only naturally emerges from both intervalley electron-phonon coupling and fluctuations of the nearby correlated insulator, but also exhibits nodal and gapped regimes as indicated by scanning tunneling microscopy experiments. Here we study band-off-diagonal pairing within Eliashberg theory. We show that despite the additional frequency dependence, the leading-order description of both intervalley coherent fluctuations or intervalley phonons exhibits a symmetry prohibiting admixture of an intraband component to the interband pairing state. It is found that even- and odd-frequency pairing mix, which originates from the reduced number of flavor degrees of freedom in the normal state. From analytic continuation, we obtain the electronic spectral function showing that, also within Eliashberg theory, the interband nature leads to an enhanced spectral weight below the order-parameter energy compared to band-diagonal pairing. Finally, we also study the superfluid stiffness of band-off-diagonal pairing, taking into account multi-band and quantum geometry effects. It is shown that for \(s\)-wave and chiral momentum dependencies, conventionally leading to fully gapped phases, an interband structure reduces the temperature scale below which the stiffness saturates. Depending on parameters, for the chiral state, this scale can even be suppressed all the way to zero temperature leading to a complex competition of multiple dispersive and geometrical contributions. Our results show that interband pairing might also be able to explain more recent stiffness measurements in the superconducting state of twisted multilayer graphene.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Field-induced phase transitions in the Kitaev-Heisenberg model: A sign-problem-free quantum Monte Carlo study and possible application to \(\alpha\)-RuCl3
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Xuan Zou, Shuo Liu, Wenan Guo, Hong Yao
The frustrated magnet \(\alpha\)-RuCl3 is one of the prime candidates for realizing a Kitaev quantum spin liquid (QSL). However, the existence of a field-induced intermediate QSL phase in this material remains under debate. Here, we employ sign-free numerically exact quantum Monte Carlo simulations to investigate the Kitaev-Heisenberg (KH) model on the honeycomb lattice with \(K=-2J\) under an applied magnetic field along the z-direction. Our findings reveal that the system undergoes a direct quantum phase transition from a zigzag magnetically ordered phase to a spin-polarized phase at zero temperature, which belongs to the 3D XY universality class. At finite temperatures, a Berezinskii-Kosterlitz-Thouless transition line separates the spin-polarized phase from a quasi-long-range ordered state, eventually terminating at the quantum critical point. Our results convincingly show that there is no intermediate QSL phase in the KH model with a z-direction magnetic field, which we believe will shed important light on understanding experimental observations in \(\alpha\)-RuCl3.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
4.5 pages, 5 figures
Classical Fractons: Local chaos, global broken ergodicity and an arrow of time
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-23 20:00 EST
Aryaman Babbar, Ylias Sadki, Abhishodh Prakash, S. L. Sondhi
We report new results on classical, Machian, fractons. For fractons of strictly bounded Machian range, we show that local clusters do not exhibit chaos while the global state breaks ergodicity. We show that the many fracton evolution characteristically exhibits a central time or Janus point and thus a generic non-equilibrium arrow of time as discussed previously in the context of classical Cosmology.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Classical Physics (physics.class-ph)
15 pages, 7 figures
Transfer learning electronic structure: millielectron volt accuracy for sub-million-atom moir'e semiconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Ting Bao, Ning Mao, Wenhui Duan, Yong Xu, Adrian Del Maestro, Yang Zhang
The integration of density functional theory (DFT) with machine learning enables efficient electronic structure calculations for ultra-large systems. In this work, we develop a transfer learning framework tailored for long-wavelength moiré systems. To balance efficiency and accuracy, we adopt a two-step transfer learning strategy: (1) the model is pre-trained on a large dataset of computationally inexpensive non-twisted structures until convergence, and (2) the network is then fine-tuned using a small set of computationally expensive twisted structures. Applying this method to twisted MoTe\(_2\), the neural network model generates the resulting Hamiltonian for a 1000-atom system in 200 seconds, achieving a mean absolute error below 0.1 meV. To demonstrate \(O(N)\) scalability, we model nanoribbon systems with up to 0.25 million atoms (\(\sim9\) million orbitals), accurately capturing edge states consistent with predicted Chern numbers. This approach addresses the challenges of accuracy, efficiency, and scalability, offering a viable alternative to conventional DFT and enabling the exploration of electronic topology in large scale moiré systems towards simulating realistic device architectures.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
5+14 pages, 4+ 11 figures
Effect of Pt bottom electrode texture selection on the tetragonality and physical properties of Ba0.8Sr0.2TiO3 thin films produced by pulsed laser deposition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
J. P. B. Silva, K. C. Sekhar, A. Almeida, J. Agostinho Moreira, J. Martín-Sánchez, M. Pereira, A. Khodorov, M. J. M. Gomes
The effect of platinum (Pt) bottom electrode texture on the tetragonality, dielectric, ferroelectric, and polarization switching response of pulsed laser deposited Ba0.8Sr0.2TiO3 (BST) thin films has been studied. The x-ray diffraction and Raman analysis revealed the higher tetragonality of BST films when they were grown on higher (111) textured Pt layer. The properties like dielectric permittivity, polarization, switching time, and leakage currents were found to be correlated to tetragonality and orientation of the BST films. The polarization current was observed to be higher in BST films on Pt epitaxial layer and it exhibits exponential dependence on the electric field. The voltage-current measurements displayed Ohmic behavior of leakage current irrespective of Pt texture for low voltages (up to 1 V), whereas at higher voltages the conduction mechanism was found to be dependent on texture selection of bottom Pt electrode.
Materials Science (cond-mat.mtrl-sci)
23 pages, 14 figures
J. Appl. Phys. 112, 044105 (2012)
Self-assembling of Ge quantum dots in an alumina matrix
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
M. Buljan, S. R. C. Pinto, A. G. Rolo, J. Martín-Sánchez, M. J. M. Gomes, J. Grenzer, A. Mücklich, S. Bernstorff, V. Holý
In this work we report on a self-assembled growth of a Ge quantum dot lattice in a single 600-nm-thick Ge+Al2O3 layer during magnetron sputtering deposition of a Ge+Al2O3 mixture at an elevated substrate temperature. The self-assembly results in the formation of a well-ordered threedimensional body-centered tetragonal quantum dot lattice within the whole deposited volume. The quantum dots formed are very small in size less than 4.0 nm, have a narrow size distribution and a large packing density. The parameters of the quantum dot lattice can be tuned by changing the deposition parameters. The self-ordering of the quantum dots is explained by diffusionmediated nucleation and surface-morphology effects and simulated by a kinetic Monte Carlo model.
Materials Science (cond-mat.mtrl-sci)
Phys. Rev. B 82, 235407 (2010)
Critical Dynamics of Spin Boson Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-23 20:00 EST
M. G. Vasin, S. V. Remizov, A. A. Elistratov
In this work, we study the low-energy properties of the spin-boson model (SBM), which describes the dynamics of a 1/2 spin associated with a thermostat characterized by a power law spectral density, \(f(\omega)\propto |\omega|^s\). The theoretical description is constructed in the Schwinger--Keldysh technique, based on the representation of the 1/2-spin by Majorana fermions. We study the critical dynamics of the system near the quantum phase transition by constructing and analyzing the system of renormalization group equations. Our theoretical approach is more universal, contrary to the one based on quantum classical mapping, since it is applicable for \(0<s\leq 1\). We show that in both the ohmic case \(s=1\), and subohmic case \(0<s<1\), the second order quantum phase transition is observed in the model considered, and the critical magnetization exponent agrees with the exact hyperscaling result, \(1/\delta=(1-s)/(1+s)\). Furthermore, we obtain the dependence of the critical value of the spin-boson coupling constant on the temperature of the bosonic thermal bath.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
5 pages, 4 figures
Entanglement asymmetry dynamics in random quantum circuits
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-23 20:00 EST
Filiberto Ares, Sara Murciano, Pasquale Calabrese, Lorenzo Piroli
We study the dynamics of entanglement asymmetry in random unitary circuits (RUCs). Focusing on a local \(U(1)\) charge, we consider symmetric initial states evolved by both local one-dimensional circuits and geometrically non-local RUCs made of two-qudit gates. We compute the entanglement asymmetry of subsystems of arbitrary size, analyzing the relaxation time scales. We show that the entanglement asymmetry of the whole system approaches its stationary value in a time independent of the system size for both local and non-local circuits. For subsystems, we find qualitative differences depending on their size. When the subsystem is larger than half of the full system, the equilibration time scales are again independent of the system size for both local and non-local circuits and the entanglement asymmetry grows monotonically in time. Conversely, when the subsystems are smaller than half of the full system, we show that the entanglement asymmetry is non-monotonic in time and that it equilibrates in a time proportional to the quantum-information scrambling time, providing a physical intuition. As a consequence, the subsystem-equilibration time depends on the locality of interactions, scaling linearly and logarithmically in the system size, respectively, for local and non-local RUCs. Our work confirms the entanglement asymmetry as a versatile and computable probe of symmetry in many-body physics and yields a phenomenological overview of entanglement-asymmetry evolution in typical non-integrable dynamics.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
25 pages, 10 figures
Magnetic Properties of Potential Li-ion Battery Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Md Rakibul Karim Akanda, Amaya Alexandria Holmes, Jinorri Wilson
Lithium-ion batteries (LiBs) have transformed electrochemical energy storage technologies and made a substantial contribution to grid-scale energy storage and the e-mobility revolution. Notwithstanding their many benefits, safety issues specifically, thermal runaway incidents have drawn attention from all around the world. In addition to discussing safety concerns, cooling techniques, and the history of battery materials, this study offers a thorough analysis of the growth, difficulties, and developments in Li-ion battery technology. Quantum Espresso software has been used to compute the magnetic characteristics of several potential Li-ion battery materials, which can enhance Li-ion battery performance.
Materials Science (cond-mat.mtrl-sci)
Global symmetries of quantum lattice models under non-invertible dualities
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Weiguang Cao, Yuan Miao, Masahito Yamazaki
Non-invertible dualities/symmetries have become an important tool in the study of quantum field theories and quantum lattice models in recent years. One of the most studied examples is non-invertible dualities obtained by gauging a discrete group. When the physical system has more global symmetries than the gauged symmetry, it has not been thoroughly investigated how those global symmetries transform under non-invertible duality. In this paper, we study the change of global symmetries under non-invertible duality of gauging a discrete group \(G\) in the context of (1+1)-dimensional quantum lattice models. We obtain the global symmetries of the dual model by focusing on different Hilbert space sectors determined by the \(\mathrm{Rep}(G)\) symmetry. We provide general conjectures of global symmetries of the dual model forming an algebraic ring of the double cosets. We present concrete examples of the XXZ models and the duals, providing strong evidence for the conjectures.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
31 pages, 4 figures
Director-layer dynamics in the smectic-ZA phase of a ferroelectric nematic liquid crystal
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-23 20:00 EST
Arjun Ghimire, Bijaya Basnet, Hao Wang, Parikshit Guragain, Alan Baldwin, Robert Twieg, Oleg Lavrentovich, James Gleeson, Antal Jakli, Samuel Sprunt
A dynamic light scattering study of director-layer fluctuations in the anti-ferroelectric smectic-ZA phase of the ferroelectric nematic liquid crystal DIO is reported. The dynamics are consistent with the distinctive feature of the ZA phase that the smectic layers form parallel to the axis of molecular orientational order (director). A model is developed to describe quantitatively the dispersion of the fluctuation relaxation rates. The model is based on a specialization of the elastic free energy density of the smectic-C phase to the case of 90 degree director tilt, a "first-order" approximation of the viscous stresses by their form for an incompressible uniaxial fluid, and a treatment of the effect of chevron layer structure that develops in planar sample cells due to temperature-dependent layer shrinkage, as documented in previous studies on DIO. From the modeling, the layer compression elastic constant is estimated to be ~100 times lower in the smectic-ZA phase than in an ordinary smectic-A liquid crystal. Possible effects of the antiferroelectric layer polarization on the director splay elasticity and viscosity are described. The temperature dependencies of the splay, twist, and bend elastic constants and associated viscosities in the higher temperature nematic phase are also presented.
Soft Condensed Matter (cond-mat.soft)
Structural and mechanical properties of W-Cu compounds characterized by a neural-network-based potential
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Jianchuan Liu, Tao Chen, Sheng Mao, Mohan Chenb
Tungsten-copper (W-Cu) compounds are widely utilized in various industrial fields due to their exceptional mechanical properties. In this study, we have developed a neural-network-based deep potential (DP) model that covers a wide range of temperatures, ranging from 0 to 3,000 K, and pressures, varying from 0 to 10 GPa. This study presents a model trained using density functional theory data for full concentration CuxW100-x compounds. Through this model, we systematically investigate the structural and mechanical properties of W-Cu alloys and have the following findings. First, the bulk modulus (B) and Young's modulus (E) of W-Cu alloys exhibit a linear decline as the Cu content increases, indicating a softening trend in the CuxW100-x compounds as the Cu concentration rises. Second, a higher Cu content results in higher critical strain and lower critical stress for these compounds. A brittle-to-ductile transition in the deformation mode predicted is predicted at around 37.5 at. % Cu content. Third, tensile loading tests in the W-Cu gradient structure reveal that Cu-poor region serves as a barrier, hindering shear band propagation while promoting new shear band formation in the Cu-rich region. The above results from the DP model are anticipated to aid in exploring the physical mechanisms underlying the complex phenomena of W-Cu systems and contribute to the advancement of methodologies for materials simulation.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
On the nature of rubber wear
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-23 20:00 EST
R. Xu, N. Miyashita, B.N.J. Persson
Rubber wear results from the removal of small (micrometer-sized) rubber particles through crack propagation. In this study, we investigate the wear behavior of Styrene-Butadiene Rubber (SBR) and Natural Rubber (NR) sliding on two different concrete surfaces under dry and wet conditions. Experiments were conducted at low sliding speeds (\(\approx 1 \ {\rm mm/s}\)) to minimize frictional heating and hydrodynamic effects. For two SBR compounds, we observe significantly higher wear rates in water compared to the dry state, with enhancement factors of \(1.5-2.5\) for a low-glass-transition-temperature SBR compound (\(T_{\rm g} = -50^\circ {\rm C}\)) and approximately \(4\) for a higher-glass-transition compound (\(T_{\rm g} = -7^\circ {\rm C}\)). In contrast, the NR compound showed no wear in water at low nominal contact pressures (\(\sigma_0 \approx 0.12\), \(0.16\), and \(0.25 \ {\rm MPa}\)), while at higher pressures (\(\sigma_0 \approx 0.36\) and \(0.49 \ {\rm MPa}\)), the wear rates in dry and wet states were similar. The experimental results are analyzed using a recently developed rubber wear theory. The findings provide insights into the mechanisms of rubber wear under varying environmental and mechanical conditions, highlighting the influence of material properties, interfacial effects, and applied pressures on wear behavior.
Soft Condensed Matter (cond-mat.soft)
Spin-Triplet Excitonic Insulator in the Ultra-Quantum Limit of HfTe5
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Jinyu Liu, Varsha Subramanyan, Robert Welser, Timothy McSorley, Triet Ho, David Graf, Michael T. Pettes, Avadh Saxena, Laurel E. Winter, Shi-Zeng Lin, Luis A. Jauregui
More than fifty years ago, excitonic insulators, formed by the pairing of electrons and holes due to Coulomb interactions, were first predicted. Since then, excitonic insulators have been observed in various classes of materials, including quantum Hall bilayers, graphite, transition metal chalcogenides, and more recently in moire superlattices. In these excitonic insulators, an electron and a hole with the same spin bind together and the resulting exciton is a spin singlet. Here, we report the experimental observation of a spin-triplet exciton insulator in the ultra-quantum limit of a three-dimensional topological material HfTe5. We observe that the spin-polarized zeroth Landau bands, dispersing along the field direction, cross each other beyond a characteristic magnetic field in HfTe5, forming the one-dimensional Weyl mode. Transport measurements reveal the emergence of a gap of about 250 {}eV when the field surpasses a critical threshold. By performing the material-specific modeling, we identify this gap as a consequence of a spin-triplet exciton formation, where electrons and holes with opposite spin form bound states, and the translational symmetry is preserved. The system reaches charge neutrality following the gap opening, as evidenced by the zero Hall conductivity over a wide magnetic field range (10 - 72 T). Our finding of the spin-triplet excitonic insulator paves the way for studying novel spin transport including spin superfluidity, spin Josephson currents, and Coulomb drag of spin currents in analogy to the transport properties associated with the layer pseudospin in quantum Hall bilayers.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Universal scaling of electrostatic effects of a curved counter-electrode on the emitter field enhancement
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Thiago A. de Assis, Fernando F. Dalll'Agnol
Experiments on field electron emission from single-tip nanoemitters have typically been carried out using a counter-electrode with a finite curvature radius \(R\), positioned at a distance \(d_{\rm{gap}}\) from the emitter's apex. The effects of the counter-electrode's curvature on the apex field enhancement factor (\(\gamma_{\rm{Ca}}\)) of the emitter are still not understood. In this Letter, we theoretically explore how the apex field enhancement factor of an emitter, represented by a hemisphere on a cylindrical post (HCP) with apex radius \(r_{\rm{a}} = 50\)nm, is influenced by the curvature of a spherical-shaped counter-electrode. Importantly, our results show that for HCPs with sharpness aspect ratios typically between \(10^2\) and \(10^3\), there is a universal scaling such that \(\gamma_{\rm{Ca}} = \gamma_{\rm{Pa}} \Psi\left({R}/{d_{\rm{gap}}} \right)\), where \(\gamma_{\rm{Pa}}\) represents the apex field enhancement factor for the emitter assuming a planar counter-electrode, and \(\Psi\left({R}/{d_{\rm{gap}}} \right)\) is a universal scaling function such that \(\Psi \sim 1\) for \({R}/{d_{\rm{gap}}} \gg 1\) and \(\Psi \sim \left({R}/{d_{\rm{gap}}} \right)^{\alpha}\), with \(\alpha\) close to unity, for $ {R}/{d_{}} $. These findings help partially explain discrepancies observed in orhtodox field electron emission experiments, who reported that the effective \(\gamma_{\rm{Ca}}\) values extracted from the current-voltage characteristics of single-tip carbon nanotubes typically underestimate the theoretical \(\gamma_{\rm{Pa}}\) values when \(R \sim d_{\rm{gap}} \gg r_{\rm{a}}\), a trend that is predicted by our results.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
This is a revised version of our original Letter submitted to Applied Physics Letters on December 9, 2024. This revised version was resubmitted to Applied Physics Letters on January 20, 2025
Tuning the topological winding number by rolling up graphene
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Ying-Je Lee, Yu-An Cheng, Yu-Jie Zhong, Ion Cosma Fulga, Ching-Hao Chang
Nanoscrolls, radial superlattices formed by rolling up a nanomembrane, exhibit distinct electronic and magneto-transport properties compared to their flat counterparts. In this study, we theoretically demonstrate that the conductance can be precisely enhanced N times by rolling up graphene into an N-turn nanoscroll and applying a longitudinal magnetic field. This tunable positive magnetoconductance stems from the topological winding number which is activated in a carbon nanoscroll with magnetic flux and its maximum value purely increases with the scroll winding number (the number of turns). By integrating material geometry and topology, our work opens the door to artificially creating, customizing, and designing topological materials in rolled-up graphene-like systems.
Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
5 pages, 4 figures
Enhanced Field-Free Perpendicular Magnetization Switching via spin splitting torque in Altermagnetic RuO2-based Heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Badsha Sekh, Hasibur Rahaman, Ramu Maddu, Pinkesh Kumar Mishra, Tianli Jin, S.N. Piramanayagam
Current-induced spin-orbit torque (SOT) has emerged as a promising method for achieving energy-efficient magnetization switching in advanced spintronic devices. However, technological advancement has been inadequate because an external in-plane magnetic field is required to attain deterministic switching. Several approaches have been explored to address these challenges. In this work, we explored the potential of a newly emerged altermagnetic material RuO2 in combination with a Pt layer to achieve both field-free and low-power switching concurrently. We leveraged out-of-plane (OOP) spin polarization via the spin-splitter effect (SSE) in RuO2 for field-free switching (FFS) and in-plane spin polarization combined with spin Hall effect (SHE) in Pt for enhanced SOT efficiency. We revealed that the effective OOP magnetic field and FFS can be maximized by tuning the nominal thickness of the Pt underlayer and the direction of the applied current. We observed a significant enhancement in FFS at an optimized Pt thickness of 1.5 nm for an applied current density as low as 2.56e11 A/m2 at a crystal angle of 90 deg. Our study paves the way for energy-efficient spintronics devices for non-volatile memory, logic circuits, and neuromorphic computing.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 5 figures
Ferroelectricity in undoped HfO2 down to one-unit-cell on Si substrate
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Tiantian Wang, He Zhang, Yongjie Xie, Subi Du, Da Sheng, Zhaolong Liu, Sheng Wang, Hui Li, Qinghua Zhang, Kai Wang, Bing Xu, Xianggang Qiu, Yang Xu, Lin Gu, Xiaolong Chen
Hafnium oxide (HfO2), particularly at low-dimensional scales, exhibits extensive promising applications in ultrahigh density devices like low-power logic and non-volatile memory devices due to its compatibility with current semiconductor technology1-5. However, achieving ferroelectricity (FE) at ultimate scale especially in undoped HfO2 remains challenging as the non-centrosymmetric FE phase, so-called O-III (space group: Pca21) is metastable and FE has a strong tendency of depolarization with the decrease in thickness6. Up to now, this phase has usually stabilized via doping with other elements7-9. But the minimum film thickness is still limited to 1 nm, about 2-unit-cell, to keep FE8. Thinner and undoped films, conducive to further miniature device size and avoid contamination during deposition process, have been a challenge to fabricate on Si substrates. Herein, we report the robust FE observed in undoped HfO2 ultrathin films directly grown on Si substrate via atomic layer deposition (ALD) and post-heat treat in vacuum. The so-fabricated ferroelectric O-III phase contains about 4.48 at% oxygen vacancy, is robust even monoclinic phase (space group: P21/c) coexists. The spontaneous and switchable polarization is remarkably stable, still surviving even in films down to 0.5 nm (one-unit-cell). Our results show the robust FE O-III phase can be obtained in films down to one-unit-cell in thickness on Si, providing a practical way to fabricating this important material in thickness limit.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
Stretching the Printability Metric in Direct-ink Writing with Highly Extensible Yield-Stress Fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-23 20:00 EST
Chaimongkol Saengow, Samya Sen, Joaquin Yus, Eliza E. Lovrich, Amanda G. Hoika, Kelly M. Chang, Arielle A. Pfeil, Nellie Haug, Amy J. Wagoner Johnson, Randy H. Ewoldt
Direct-ink writing leverages the rheological complexity of yield-stress fluids to construct complex geometries, particularly those with large gaps across internal structures. However, extensional rheological properties have rarely been considered in work that studies rheology-printability correlations. Here, we test our hypothesis that extensional properties correlate with drawability, a key indicator of printability that signifies speed robustness, printing resolution, and gap-spanning performance. We formulated cementitious suspensions using hydroxyapatite (HAp) particles, independently tuning them for yield stress and extensibility, two crucial rheological properties, and test-printed. To enhance extensibility, we incorporated hydroxypropyl methylcellulose as a polymeric modifier, but this enhancement may decrease as yield stress increases, presenting a challenge in materials design. We modulated particle interactions to achieve a wide range of yield stress and extensibility, allowing for rigorous testing of our hypothesis. This approach created inks with high extensibility and high yield stress, generally considered mutually exclusive properties. We evaluated correlations between drawability and key rheological properties, finding the strongest positive correlation with extensional failure strains (strain-to-break) rather than yield stress. We establish a bijective property-manufacturing relationship (one-on-one mapping of shear yield stress to buildability and extensional strain-to-break to drawability) by combining our findings on drawability with previous studies on buildability. This relationship provides a comprehensive framework for designing high-performance inks that can be self-supporting, capable of high-speed printing, and allow gap-spanning features.
Soft Condensed Matter (cond-mat.soft)
Giant Third-Order Nonlinearity Induced by the Quantum Metric Quadrupole in Few-Layer WTe2
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Xing-Yu Liu, An-Qi Wang, Dong Li, Tong-Yang Zhao, Xin Liao, Zhi-Min Liao
The quantum geometric properties of topological materials underpin many exotic physical phenomena and applications. Quantum nonlinearity has emerged as a powerful probe for revealing these properties. The Berry curvature dipole in nonmagnetic materials and the quantum metric dipole in antiferromagnets have been explored by studying the second-order nonlinear Hall effect. Although the quadrupole moment of the quantum geometric tensor is theoretically predicted to induce higher-order quantum nonlinearity, the quantum metric quadrupole remains experimentally unexplored. Here, we report the quantum metric quadrupole induced third-order nonlinear longitudinal electrical response in few-layer WTe2, persisting up to room temperature. Angle-resolved third-harmonic current-voltage characteristics are found consistent with the intrinsic crystal symmetry of WTe2. Through temperature variation and scaling analysis, we identify the quantum metric quadrupole as the physical origin of the observed third-order longitudinal nonlinearity. Additionally, we determine the angle dependence of the quantum metric quadrupole, establishing third-order nonlinearity as an efficient method for revealing the quantum metric structure.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Phys. Rev. Lett. 134, 026305 (2025)
Tensor cross interpolation approach for quantum impurity problems based on the weak-coupling expansion
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Shuta Matsuura, Hiroshi Shinaoka, Philipp Werner, Naoto Tsuji
We apply the tensor cross interpolation (TCI) algorithm to solve equilibrium quantum impurity problems with high precision based on the weak-coupling expansion. The TCI algorithm, a kind of active learning method, factorizes high-dimensional integrals that appear in the perturbative expansion into a product of low-dimensional ones, enabling us to evaluate higher-order terms efficiently. This method is free from the sign problem which quantum Monte Carlo methods sometimes suffer from, and allows one to directly calculate the free energy. We benchmark the TCI impurity solver on an exactly solvable impurity model, and find good agreement with the exact solutions. We also incorporate the TCI impurity solver into the dynamical mean-field theory to solve the Hubbard model, and show that the metal-to-Mott insulator transition is correctly described with comparable accuracy to the Monte Carlo methods. Behind the effectiveness of the TCI approach for quantum impurity problems lies the fact that the integrands in the weak-coupling expansion naturally have a low-rank structure in the tensor-train representation.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 5 figures
Current-induced magnetoresistance hysteresis in the kagome superconductor CsV\(_3\)Sb\(_5\)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-23 20:00 EST
Han-Xin Lou, Xing-Guo Ye, Xin Liao, Qing Yin, Da-Peng Yu, Zhi-Min Liao
We report the observation of current-modulated magnetoresistance hysteresis below the superconducting transition temperature in the kagome superconductor CsV\(_3\)Sb\(_5\). This highly tunable hysteresis behavior is confined to the superconducting state and vanishes when superconductivity is fully suppressed, directly linking magnetoresistance hysteresis to the superconducting order in CsV\(_3\)Sb\(_5\). Additionally, the superconducting diode effect driven by a small magnetic field is observed, indicating the enhanced electronic magnetochiral anisotropy by the chiral domain-wall scattering. Our findings position CsV\(_3\)Sb\(_5\) as a promising platform for exploring nontrivial physical phenomena, including unconventional pairing mechanisms and topological superconductivity.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Phys. Rev. B 111, 014503 (2025)
Absence of superconductivity and density-wave transition in ambient-pressure tetragonal La\(_4\)Ni\(_3\)O\(_{10}\)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-23 20:00 EST
Mengzhu Shi, Yikang Li, Yuxing Wang, Di Peng, Shaohua Yang, Houpu Li, Kaibao Fan, Kun Jiang, Junfeng He, Qiaoshi Zeng, Dongsheng Song, Binghui Ge, Ziji Xiang, Zhenyu Wang, Jianjun Ying, Tao Wu, Xianhui Chen
The recent discovery of superconductivity in La\(_3\)Ni\(_2\)O\(_7\) and La\(_4\)Ni\(_3\)O\(_{10}\) under high pressure stimulates intensive research interests. These nickelates crystallize in an orthogonal/monoclinic structure with tilted NiO\(_6\) octahedra at ambient pressure and enter a density-wave-like phase at low temperatures. The application of pressure suppresses the octahedral tilting and triggers a transition to tetragonal structure (I4/mmm), which is believed to be a key prerequisite for the emergence of superconducting state. Here, by developing a high oxidative environment growth technology, we report the first tetragonal nickelates La\(_4\)Ni\(_3\)O\(_{10}\) microcrystals without octahedral tilting at ambient pressure. In tetragonal La\(_4\)Ni\(_3\)O\(_{10}\), transport measurements find that both density-wave and superconducting transitions are absent up to 160 GPa, indicating a robust tetragonal metallic ground state. Density functional theory calculations reveal that the band structure of ambient-pressure tetragonal La\(_4\)Ni\(_3\)O\(_{10}\) involves more \(d_{z2}\) orbital contribution to the Fermi surface, compared to the monoclinic phase or the high-pressure superconducting tetragonal phase. The concurrent absence of density-wave state and high-pressure superconductivity in our ambient-pressure tetragonal crystals of La\(_4\)Ni\(_3\)O\(_{10}\) suggests an underlying correlation between these two orders. It suggests that the tetragonal structure is not necessary, while the density-wave state is crucial for the superconductivity in nickelates. Our findings impose important constraints on the mechanism of pressure-induced superconductivity in nickelates and sheds new light on exploring ambient pressure high-temperature Ni-based superconductors.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
submitted
Engineering nonlinear Hall effect in bilayer graphene/black phosphorus heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Xing-Guo Ye, Zhen-Tao Zhang, Peng-Fei Zhu, Wen-Zheng Xu, An-Qi Wang, Zhi-Min Liao
Two-dimensional van der Waals materials offer a highly tunable platform for generating emergent quantum phenomena through symmetry breaking. Stacking-induced symmetry breaking at interfaces provides an effective method to modulate their electronic properties for functional devices. Here, we strategically stack bilayer graphene with black phosphorus, a low-symmetry semiconductor, to break the symmetries and induce the nonlinear Hall effect (NLHE) that can persist up to room temperature. Intriguingly, it is found the NLHE undergoes sign reversals by varying the electrical displacement field under fixed carrier density. The scaling analysis reveals that the sign reversal of the NLHE is contributed from both the Berry curvature dipole (BCD) and extrinsic scatterings. The displacement field-induced sign reversal of the BCD indicates asymmetric distributions of Berry curvature hot spots across different Fermi pockets in bilayer graphene. Our findings suggest that symmetry engineering of van der Waals heterostructures is promising for room-temperature applications based on nonlinear quantum devices, such as high-frequency rectifiers and wireless charging.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Phys. Rev. B 111, L041403 (2025)
Heat Transport Hysteresis Generated through Frequency Switching of a Time-Dependent Temperature Gradient
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
A stochastic energetics framework is applied to examine how periodically shifting the frequency of a time-dependent oscillating temperature gradient affects heat transport in a nanoscale molecular model. We specifically examine the effects that frequency switching, i.e., instantaneously changing the oscillation frequency of the temperature gradient, has on the shape of the heat transport hysteresis curves generated by a particle connected to two thermal baths, each with a temperature that is oscillating in time. Analytical expressions are derived for the energy fluxes in/out of the system and the baths, with excellent agreement observed between the analytical expressions and the results from nonequilibrium molecular dynamics simulations. We find that the shape of the heat transport hysteresis curves can be significantly altered by shifting the frequency between fast and slow oscillation regimes. We also observe the emergence of features in the hysteresis curves such as pinched loops and complex multi-loop patterns due to the frequency shifting. The presented results have implications in the design of thermal neuromorphic devices such as thermal memristors and thermal memcapacitors.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
Entropy 27(1), 18 (2025)
Inducing Spin Splitting and Anomalous Valley Hall Effect in A-Type AFM Fe\(_2\)C(OH)\(_2\) through Electric Field and Janus Engineering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Ankita Phutela, Saswata Bhattacharya
The antiferromagnetic (AFM) materials are distinguished by zero net magnetic moment, high resistance to external magnetic disturbances, and ultrafast dynamic responses. For advancing AFM materials in spintronic and valleytronic applications, achieving spontaneous valley polarization and the anomalous valley Hall effect (AVHE) is pivotal. We predict an A-type AFM monolayer Fe\(_2\)C(OH)\(_2\), which shows a significant spontaneous valley polarization of 157 meV. In Fe\(_2\)C(OH)\(_2\), spatial inversion symmetry (P) and time-reversal symmetry (T) are individually broken, yet the combined PT symmetry is preserved. This symmetry conservation leads to spin degeneracy, resulting in zero Berry curvature in the momentum space and absence of AVHE. However, a layer-locked hidden Berry curvature is produced, leading to the observation of the valley layer-spin Hall effect. Further, an external out-of-plane electric field can induce spin splitting by introducing layer-dependent electrostatic potential, enabling the layer-locked AVHE. Additionally, the introduction of a built-in electric field caused by the Janus structure also induces spin splitting in monolayer Fe\(_2\)C(OH)F due to the electric-potential-difference-AFM mechanism. The high out-of-plane magnetic anisotropy and realization of AVHE, offer promising opportunities for next-generation spintronic technologies.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Quantum Emitters in Hexagonal Boron Nitride: Principles, Engineering and Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Thi Ngoc Anh Mai, Md Shakhawath Hossain, Nhat Minh Nguyen, Yongliang Chen, Chaohao Chen, Xiaoxue Xu, Quang Thang Trinh, Toan Dinh, Toan Trong Tran
Solid-state quantum emitters, molecular-sized complexes releasing a single photon at a time, have garnered much attention owing to their use as a key building block in various quantum technologies. Among these, quantum emitters in hexagonal boron nitride (hBN) have emerged as front runners with superior attributes compared to other competing platforms. These attributes are attainable thanks to the robust, two-dimensional lattice of the material formed by the extremely strong B-N bonds. This review discusses the fundamental properties of quantum emitters in hBN and highlights recent progress in the field. The focus is on the fabrication and engineering of these quantum emitters facilitated by state-of-the-art equipment. Strategies to integrate the quantum emitters with dielectric and plasmonic cavities to enhance their optical properties are summarized. The latest developments in new classes of spin-active defects, their predicted structural configurations, and the proposed suitable quantum applications are examined. Despite the current challenges, quantum emitters in hBN have steadily become a promising platform for applications in quantum information science.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics), Quantum Physics (quant-ph)
Electron transport properties of heterogeneous interfaces in solid electrolyte interphase on lithium metal anodes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Xiangyi Zhou, Rongzhi Gao, Ziyang Hu, Weijun Zhou, YanHo Kwok, GuanHua Chen
In rechargeable batteries, electron transport properties of inorganics in the solid-electrolyte interphase (SEI) critically determine the safety, lifespan and capacity loss of batteries. However, the electron transport properties of heterogeneous interfaces among different solid inorganics in SEI have not been studied experimentally or theoretically yet, although such heterogeneous interfaces exist inevitably. Here, by employing non-equilibrium Green's function (NEGF) method, we theoretically evaluated the atomic-scale electron transport properties under bias voltage for LiF/Li2O interfaces and single-component layers of them, since LiF and Li2O are common stable inorganics in the SEI. We reveal that heterogeneous interfaces orthogonal to the external electric-field direction greatly impede electron transport in SEI, whereas heterogeneous parallel-orientated interfaces enhance it. Structural disorders induced by densely distributed interfaces can severely interfere with electron transport. For each component, single-crystal LiF is highly effective to block electron transport, with a critical thickness of 2.9 nm, much smaller than that of Li2O (19.0 nm). This study sheds a new light into direct and quantitative understanding of the electron transport properties of heterogeneous interfaces in SEI, which holds promise for the advancement of a new generation of high-performance batteries.
Materials Science (cond-mat.mtrl-sci)
This is the first time that the quantitative study of electron transport properties of atomic-scale heterogeneous interfaces in SEI has been conducted
Strong shape-dependent intensity of inelastic light scattering by gold nanocrystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
We present a numerical approach to calculate inelastic light scattering spectra from gold nanocrystals, based on the finite element method. This approach is validated by comparison with previous analytic calculations for spherically symmetric scatterers. Superellipsoid nanocrystals are considered in order to smoothly vary the shape from octahedra to cubes via spheres, while preserving cubic symmetry. Spectra are calculated and discussed taking into account the irreducible representation of the involved vibration modes. A strong increase in the inelastically scattered light intensity is observed for small variations of the shape around the sphere. This increase is related to variations of the electric field inside the nanocrystals, which are very small for small nanospheres but increase quickly for non-spherical nanocrystals. This strong dependence with shape must be taken into account when interpreting experimental spectra acquired from inhomogeneous ensembles of nanocrystals whose shape dispersion are usually neglected. The overall changes in the spectra when varying the shape of the nanocrystals provide additional insight into previously published results. Preliminary calculations for chiral shapes further show a significant difference between spectra obtained with right or left circularly polarized light.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 7 figures
Energy symmetry and interlayer wave function ratio of tunneling electrons in partially overlapped graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Oscillations of tunneling probability concerning the tunneling barrier thickness have been less studied than the decay length. In this paper, we theoretically study the dependence of the tunneling probability on the electron energy \(E\) and barrier thickness, or overlap length, in partially overlapped graphene where a gap is formed only in the central bilayer region due to a perpendicular electric field. We compare an \(\uparrow\) junction, where the current path must pass through interlayer states, with a \(\downarrow\) junction, where such interlayer transmission is not required. The valley-reversed tunneling probability of the \(\uparrow\) junction is symmetric concerning \(E\), whereas other tunneling probabilities are not. Additionally, the valley valve effect spans the entire energy gap in double \(\uparrow\) junctions, whereas it occurs only within a much narrower energy range in double \(\downarrow\) junctions. Surprisingly, these results suggest that the interlayer wavefunction ratio \(\beta\) has a more significant effect in the \(\downarrow\) junction than in the \(\uparrow\) junction. This can be understood through the energy symmetry arising from chirality operation, \(\pi\) rotation, and probability conservation. This energy symmetry offers a new perspective for analyzing the effects of \(\beta\).
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
14 pages, 8 figures
Anomalous Lattice Effect Originated Metal-Insulator Transition in FeSe\(_x\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Shubham Purwar, Shinjini Paul, Kritika Vijay, R. Venkatesh, Soma Banik, P. Mahadevan, S. Thirupathaiah
We present a comprehensive investigation of the structural, electrical transport, and magnetic properties of FeSe\(_{\it{x}}\) (\(\it{x}\) = 1.14, 1.18, 1.23, 1.28, and 1.32) to unravel the mechanism of the metal-insulator transition observed in these systems. For this, we systematically evaluated the structural parameters of FeSe\(_{\it{x}}\) as a function of Se concentration and temperature. We observe increased lattice constants and cell volume with increased Se concentration. On the other hand, the temperature-dependent XRD studies suggest unusual lattice change around the metal-insulator (MI) transition temperature of the respective compositions. This remarkable observation suggests that the anomalous lattice effect originates the MI transition in these systems. Additionally, our density of states (DOS) calculations on FeSe\(_{1.14}\) qualitatively explain the MI transition, as the low-temperature (50 K) structure DOS suggests a metallic nature and the high-temperature (300 K) structure DOS shows a gap near the Fermi level.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
14 pages, 12 Figures
Thermodynamics of \(s_{\pm}-to-s_{++}\) transition in iron pnictides in the vicinity of the Born limit
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-23 20:00 EST
Vadim Shestakov, Maxim M. Korshunov
To study thermodynamical properties of the disorder-induced transition between \(s_{\pm}\) and \(s_{++}\) superconducting gap functions, we calculate the grand thermodynamic potential \(\Omega\) in the normal and the superconducting states. Expression for the difference between the two, \(\Delta\Omega\), is derived for a two-band model for Fe-based systems with nonmagnetic impurities. The disorder is considered in a \(\mathcal{T}\)-matrix approximation within the multiband Eliashberg theory. In the vicinity of the Born limit near the \(s_{\pm}\)-to-\(s_{++}\) transition, we find two solutions obtained for opposite directions of the system's evolution with respect to the impurity scattering rate. By calculating the change in entropy \(\Delta S\) and the change in electronic specific heat \(\Delta C\) from \(\Delta\Omega\), we show that such a hysteresis is not due to the time-reversal symmetry breaking state, but it rather points out to the first order phase transition induced by the nonmagnetic disorder. Based on the \(\Delta\Omega\) calculations, phase diagram is plotted representing the energetically favourable \(s_{\pm}\) and \(s_{++}\) states and the transition between them. At finite temperature, a first order phase transition line there is limited by a critical end point. Above that point, the sharp \(s_{\pm} \to s_{++}\) transition transforms to a crossover between \(s_{\pm}\) and \(s_{++}\) states.
Superconductivity (cond-mat.supr-con)
9 pages, 7 figures
Open questions on defining and computing the vapour-liquid surface tension by virial and test transformation approaches
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-23 20:00 EST
This work addresses four problems in defining and computing the surface tension of vapour-liquid interfaces: (1) The apparent kinetic contribution to the surface tension, and what it is that makes it appear; (2) the problem of defining the local virial, which for some purposes appears to be necessary; (3) the disagreement between results for spherical interfaces when using different methods, specifically the virial and the test area method; (4) how the surface tension values obtained from these methods can be related to the definition of the surface tension from thermodynamics - since if they cannot, it is a meaningless exercise to compute them. At the end, all these problems remain unsolved: They are "open questions."
Soft Condensed Matter (cond-mat.soft), Computational Physics (physics.comp-ph)
Correlation between magnetism and the Verwey transition in magnetite
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Karolina Podgórska, Mateusz A. Gala, Kamila Komędera, N. K. Chogondahalli Muniraju, Serena Nasrallah, Zbigniew Kąkol, Joseph Sabol, Christophe Marin, Adam Włodek, Andrzej Kozłowski, J. Emilio Lorenzo, Neven Barišić, Damian Rybicki, Wojciech Tabiś
Seeking to unravel the enigmatic Verwey transition and its interplay with magnetism, we have conducted comprehensive measurements on the temperature-dependent electrical resistivity and magnetic moment of stoichiometric and doped-magnetite single crystals at temperatures reaching 1000 K. These investigations have allowed us to identify the Curie temperature, \(T_C\), and other characteristic temperatures of the electrical resistivity. Remarkably, we have identified correlations between these temperatures and the Verwey temperature, \(T_V\), indicating that the electrical transport properties and the mechanism of the Verwey transition are closely related to the magnetic properties.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Weighted Point Configurations with Hyperuniformity: An Ecological Example and Models
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-23 20:00 EST
Ayana Ezoe, Makoto Katori, Tomoyuki Shirai
Random point configurations are said to be in hyperuniform states, if density fluctuations are anomalously suppressed in large-scale. Typical examples are found in Coulomb gas systems in two dimensions especially called log-gases in random matrix theory, in which points are repulsively correlated by long-range potentials. In infertile lands like deserts continuous survival competitions for water and nutrition will cause long-ranged repulsive interactions among plants. We have prepared digital data of spatial configurations of center-of-mass for bushes weighted by bush sizes which we call masses. Data analysis shows that such ecological point configurations do not show hyperuniformity as unmarked point processes, but are in hyperuniform states as marked point processes in which mass distributions are taken into account. We propose the non-equilibrium statistical-mechanics models to generate marked point processes having hyperuniformity, in which iterations of random thinning of points and coalescing of masses transform initial uncorrelated point processes into non-trivial point processes with hyperuniformity. Combination of real data-analysis and computer simulations shows the importance of strong correlations in probability law between spatial point configurations and mass distributions of individual points to realize hyperuniform marked point processes.
Statistical Mechanics (cond-mat.stat-mech), Adaptation and Self-Organizing Systems (nlin.AO), Biological Physics (physics.bio-ph), Populations and Evolution (q-bio.PE)
LaTeX 23 pages, 12 figures, 1 table
Hydrophilic direct bonding of (100) diamond and deposited SiO\(_2\) substrates
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Tianyin Chen, Jeffrel Hermias, Salahuddin Nur, Ryoichi Ishihara
Diamond has emerged as a leading material for solid-state spin quantum systems and extreme environment electronics. However, a major limitation is that most diamond devices and structures are fabricated using bulk diamond plates. The absence of a suitable diamond-on-insulator (DOI) substrate hinders the advanced nanofabrication of diamond quantum and electronic devices, posing a significant roadblock to large-scale, on-chip diamond quantum photonics and electronics systems. In this work, we demonstrate the direct bonding of (100) single-crystal (SC) diamond plates to PECVD-grown SiO\(_2\)/Si substrates at low temperatures and atmospheric conditions. The surfaces of the SiO\(_2\) and diamond plates are then activated using oxygen plasma and piranha solution, respectively. Bonding occurs when the substrates are brought into contact with water in between and annealed at 200\(^{\circ}\)C under atmospheric conditions, resulting in a DOI substrate. We systematically studied the influence of piranha solution treatment time and diamond surface roughness on the shear strength of the bonded substrate, devising an optimal bonding process that achieves a high yield rate of 90\(\%\) and a maximum shear strength of 9.6 MPa. X-ray photoelectron spectroscopy (XPS) was used for quantitative analysis of the surface chemicals at the bonding interface. It appears that the amount of -OH bindings increases with the initial roughness of the diamond, facilitating the strong bonding with the SiO\(_2\). This direct bonding method will pave the way for scalable manufacturing of diamond nanophotonic devices and enable large-scale integration of diamond quantum and electronic systems.
Materials Science (cond-mat.mtrl-sci)
Charging of quantum emitters in hexagonal boron nitride - graphene heterostructures due to electrostatic screening
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Madhava Krishna Prasad, Jonathan Paul Goss, Jonathan David Mar
Defect color centers in hexagonal boron nitride (hBN) have gained significant interest as single-photon emitters and spin qubits for applications in a wide range of quantum technologies. As the integration of these solid-state quantum emitters into electronic devices necessitates electrical control, it is essential to gain a deeper understanding of the mechanisms of charge control for these defect color centers in hBN/graphene heterostructures. In this Letter, we show that screening due to the encapsulation of hBN with graphene modifies the electrical levels of hBN, leading to charge transfer. Furthermore, we show that the charged defects have low-energy barriers for defect reorientation which can be overcome by moderate gate voltages. This study shows that accurate modeling of the charge state of the defect is necessary to be able to electrically control defects.
Materials Science (cond-mat.mtrl-sci)
5 pages, 6 figures
Coupling of plasmons to the two-magnon continuum in antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Pieter M. Gunnink, Alexander Mook
The coupling of magnons and plasmons offers a promising avenue for hybrid quantum systems, facilitating coherent energy and information transfer between magnetic and charge excitations. However, existing mechanisms often depend on weak spin-orbit coupling or temperature-activated processes, limiting their robustness for low-temperature quantum technologies. Here, we propose a novel coupling mechanism between plasmons and the two-magnon continuum in antiferromagnetic insulators, which operates at zero temperature and does not require spin-orbit coupling. Using a model system consisting of a two-dimensional electron gas on an insulating antiferromagnetic substrate, we show that the electric field of the plasmons interacts with the magnetically mediated electric polarization in the antiferromagnet, arising from bonds with broken inversion symmetry. This interaction enables strong coupling to the spin-conserving two-magnon continuum, allowing for efficient hybridization.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 6 figures
Super-enhanced Sensitivity in Non-Hermitian Systems at Infernal Points
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
The emergence of exceptional points in non-Hermitian systems represents an intriguing phenomenon characterized by the coalescence of eigenenergies and eigenstates. When a system approaches an exceptional point, it exhibits a heightened sensitivity to perturbations compared to the conventional band degeneracy observed in Hermitian systems. This sensitivity, manifested in the splitting of the eigenenergies, is amplified as the order of the exceptional point increases. Infernal points constitute a unique subclass of exceptional points, distinguished by their order escalating with the expansion of the system's size. In this paper, we show that, when a non-Hermitian system is at an infernal point, a perturbation of strength \(\epsilon\), which couples the two opposing boundaries of the system, causes the eigenenergies to split according to the law \(\sqrt[k]{\epsilon}\), where \(k\) is an integer proportional to the system's size. Utilizing the perturbation theory of Jordan matrices, we demonstrate that the exceptional sensitivity of the eigenenergies at infernal points to boundary-coupling perturbations is a ubiquitous phenomenon, irrespective of the specific form of the non-Hermitian Hamiltonians. Notably, we find that this phenomenon remains robust even when the system deviates slightly from the infernal point. The universal nature and robustness of this phenomenon suggest potential applications in enhancing sensor sensitivity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 + 3 pages, 2 figures
Magnetic phase diagram of cuprates and universal scaling laws
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-23 20:00 EST
Yves Noat, Alain Mauger, William Sacks
In this article we consider the magnetic field phase diagram of hole-doped high-\(T_c\) cuprates, which has been given much less attention than the temperature diagram. In the framework of the {}, we show that the two characteristic energies, the pair binding energy (the gap \(\Delta_p\)) and the condensation energy (\(\beta_c\)) resulting from pair correlations, give rise to two major magnetic fields, the upper critical field \(B_{c2}\) and a second field, \(B_{pg}\), associated with the pseudogap (PG). The latter implies a second length scale in addition to the coherence length, characteristic of incoherent pairs. Universal scaling laws for both \(B_{c2}\) and \(B_{pg}\) are derived: \(B_{c2}\) scales with the critical temperature, \(B_{c2}/T_c\simeq 1.65\) T/K, in agreement with many experiments, and \(B_{pg}\) has a similar scaling with respect to \(T^\ast\). Finally, Fermi arcs centered on the nodal directions are predicted to appear as a function of magnetic field, an effect testable experimentally.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Submitted to Physics Letters A
Topologically Charged Vortices at Superconductor/Quantum Hall Interfaces
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Enderalp Yakaboylu, Thomas Schmidt
We explore interface states between a type-II \(s\)-wave superconductor (SC) and a Chern insulator in the integer quantum Hall (QH) regime. Our results show that the effective interaction at this boundary gives rise to two emergent Abelian Higgs fields, representing paired electrons at the SC/QH interface. These fields couple to a gauge field that includes both Chern-Simons term, originating from the QH sector, and Maxwell term. Using this framework, we investigate the effects of magnetic flux vortices on the SC/QH interface. The emergence of the Chern-Simons term significantly modifies the magnetic penetration depth, influencing the Abrikosov lattice period and potentially altering the superconducting behavior at the interface. Furthermore, we demonstrate that vortex solutions at the interface carry a fractional charge of \(e/2\), which reflects the ratio between the effective Chern-Simons level parameter and the charge of the Cooper pairs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con), High Energy Physics - Theory (hep-th)
6 pages, 2 figures, and Supplemental Material
Universal Catalyst Design Framework for Electrochemical Hydrogen Peroxide Synthesis Facilitated by Local Atomic Environment Descriptors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Zhijian Liu, Yan Liu, Bingqian Zhang, Yuqi Zhang, Tianxiang Gao, Mingzhe Li, Xue Jia, Di Zhang, Heng Liu, Xuqiang Shao, Li Wei, Hao Li, Weijie Yang
Developing a universal and precise design framework is crucial to search high-performance catalysts, but it remains a giant challenge due to the diverse structures and sites across various types of catalysts. To address this challenge, herein, we developed a novel framework by the refined local atomic environment descriptors (i.e., weighted Atomic Center Symmetry Function, wACSF) combined with machine learning (ML), microkinetic modeling, and computational high-throughput screening. This framework is successfully integrated into the Digital Catalysis Database (DigCat), enabling efficient screening for 2e- water oxidation reaction (2e- WOR) catalysts across four material categories (i.e., metal alloys, metal oxides and perovskites, and single-atom catalysts) within a ML model. The proposed wACSF descriptors integrating both geometric and chemical features are proven effective in predicting the adsorption free energies with ML. Excitingly, based on the wACSF descriptors, the ML models accurately predict the adsorption free energies of hydroxyl ({}GOH) and oxygen ({}GO) for such a wide range of catalysts, achieving R2 values of 0.84 and 0.91, respectively. Through density functional theory calculations and microkinetic modeling, a universal 2e- WOR microkinetic volcano model was derived with excellent agreement with experimental observations reported to date, which was further used to rapidly screen high-performance catalysts with the input of ML-predicted {}GOH. Most importantly, this universal framework can significantly improve the efficiency of catalyst design by considering multiple types of materials at the same time, which can dramatically accelerate the screening of high-performance catalysts.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
33
Fermi surface origin of the low-temperature magnetoresistance anomaly
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Yejun Feng, Yishu Wang, T. F. Rosenbaum, P. B. Littlewood, Hua Chen
A magnetoresistance (MR) anomaly at low temperatures has been observed in a variety of systems, ranging from low-dimensional chalcogenides to spin and charge density wave (SDW/CDW) metals and, most recently, topological semimetals. In some systems parabolic magnetoresistance can rise to hundreds of thousands of times its low-temperature, zero-field value. While the origin of such a dramatic effect remains unresolved, these systems are often low-carrier-density compensated metals, and the physics is expected to be quasi-classical. Here we demonstrate that this MR anomaly in temperature also exists in high conductivity good metals with large Fermi surfaces, namely Cr, Mo, and W, for both linear and quadratic field-dependent regimes with their non-saturation attributed to open orbit and electron-hole compensation, respectively. We provide evidence that quantum transport across sharp Fermi surface arcs, but not necessarily the full cyclotron orbit, governs this low-temperature MR anomaly. In Cr, extremely sharp curvatures are induced by superposed lattice and SDW band structures. One observes an overlay of the temperature dependence of three phenomena: namely, MR at a constant high field, linear MR in the low-field limit, and Shubnikov-de Haas (SdH) oscillations of the lightest orbit. In Mo, the temperature dependence of low-T MR anomaly extends beyond those of its SdH oscillations but disappears at temperatures where Kohler's scaling reemerges. In the low-temperature and high-field limit, large magnetoresistance from carriers circling quantum orbits is the three-dimensional analogy to the zero-conductance state of carrier localization in the integer quantum Hall effect, especially with regard to the adverse effect of disorder.
Materials Science (cond-mat.mtrl-sci)
Theoretical Study of Terahertz Absorption Spectra and Neutron Inelastic Scattering in Frustrated Magnet \(\text{Tb}_2\text{Ti}_2\text{O}_7\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Within the framework of the single-particle approximation, the envelopes of the spectral lines of terahertz absorption and inelastic neutron scattering corresponding to magnetic dipole transitions between the sublevels of Tb\(^{3+}\) ions in the Tb\(_2\)Ti\(_2\)O\(_7\) crystal, split by the field of random deformations induced by point defects of the crystal lattice upon violation of the stoichiometric composition of the crystal, were calculated.
Strongly Correlated Electrons (cond-mat.str-el)
Zh.Exp.Teor.Fiz. Vol. 167 (3) (2025)
Magnetic Properties of epitaxial \(\text{Re}/\text{Co}_{1-x}\text{Au}_{x}/\text{Pt}\) heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Sukanta Kumar Jena, Anuj Kumar Dhiman, Artem Lynnyk, Kilian Lenz, Gauravkumar Ishwarbhai Patel, Aleksiej Pietruczik, Paweł Aleszkiewicz, Jürgen Lindner, Piotr Dłużewski, Ryszard Gieniusz, Andrzej Maziewski, Ewelina Milińska, Andrzej Wawro
We investigate epitaxial \(\text{Co}(20 \, \text{Å})\) and \(\text{Co}_{1-x}\text{Au}_{x}(20 \, \text{Å})\) alloy thin-films surrounded by asymmetric heavy metals layers of \(\text{Re}(10 \, \text{Å})\) as a buffer and \(\text{Pt}(30 \, \text{Å})\) as a cap to study the magnetic anisotropy, interfacial Dzyaloshinskii-Moriya interaction (iDMI) and damping. The increase of Au from 0% to 25% in the \(\text{Co}_{1-x}\text{Au}_{x}\) alloy generates the spin-reorientation transition of around 13% of Au. The increase in Au concentration provides a significant decrease in saturation magnetization from 1690 kA/m to 982 kA/m measured for Co and \(\text{Co}_{75}\text{Au}_{25}\), respectively. The effective anisotropy constant \(\text{K}_{eff}\) is elevated up to 0.33 \(\text{MJ/m}^{3}\) by changing the Au content. Further, our investigations of the magnetization dynamics have confirmed that the overall effective damping constant rises with the Au concentration which can be attributed to the spin pumping effect. The spin pumping leads to the highest value of effective spin mixing conductance \(g^{(\uparrow \downarrow)} \approx 2.91 \times 10^{18} \, \text{m}^{-2}\) in the \(\text{Co}_{90}\text{Au}_{10}(20 \, \text{Å})\) system, while the lowest value of \(g^{(\uparrow \downarrow)} \approx 2.25 \times 10^{18} \, \text{m}^{-2}\) is found for the \(\text{Co}(20 \, \text{Å})\) system. Additionally, we have investigated the iDMI strength, and the amplitude of iDMI decreases with increasing Au concentration. The highest surface iDMI constant value equal to 2.62 pJ/m is observed for Co.
Materials Science (cond-mat.mtrl-sci)
Wafer-scale robust graphene electronics under industrial processing conditions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
E. P. van Geest, B. Can, M. Makurat, C. Maheu, H. Sezen, M.D. Barnes, D. Bijl, M. Buscema, S. Shankar, D. J. Wehenkel, R. van Rijn, J.P. Hofmann, J. M. van Ruitenbeek, G. F. Schneider
For commercial grade electronic devices, stable structures are required to ensure a long device life span. When such devices contain nanomaterials like graphene, it is crucial that these materials resist industrial processes and harsh environments. For environments that contain water, graphene delamination is a notorious drawback, as water intercalation and eventually liftoff readily occur in aqueous and especially in alkaline solutions. This limitation renders graphene incompatible with key wafer-processing steps in the semiconductor industry. In this work, a covalent pyrene-based adhesion layer is synthesized in a facile, two-step procedure. Through {}-{} interactions, the adhesion of graphene to silicon wafers was maintained under conditions that resemble harsh processes, i.e. acidic and alkaline solutions, several organic solvents, and sonication. Moreover, they could be produced with a device measurement yield up to 99.7% and reproducible device-to-device electronic performance on 4-inch silicon wafers. Our results show that a straightforward functionalization of silicon wafers with an adhesive layer can be directly applicable in industrial-scale fabrication processes, giving access to robust graphene field effect devices that are built to last long.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Coherent interaction of 2s and 1s exciton states in TMDC monolayers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
Max Wegerhoff, Moritz Scharfstädt, Stefan Linden, Andrea Bergschneider
We use femtosecond pump-probe spectroscopy to study the coherent interaction of excited exciton states in WSe2 and MoSe2 monolayers via the optical Stark effect. For co-circularly polarized pump and probe, we measure a blueshift which points to a repulsive interaction between the 2s and 1s exciton states. The determined 2s-1s interaction strength is on par with that of the 1s-1s, in agreement with the semiconductor Bloch equations. Furthermore, we demonstrate the existence of a 2s-1s biexciton bound state in the cross-circular configuration in both materials and determine their binding energy.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 4 figures, supplemental material
Hole Transfer Dynamics in Thin Films of Mixed-Dimensional Quasi-2D Perovskites
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-23 20:00 EST
G. Ammirati, S. Turchini, F. Toschi, P. O'Keeffe, A. Paladini, F. Martelli, R. Khanfar, D. Takhellambam, S. Pescetelli, A. Agresti, D. Catone
The understanding of charge transfer processes in mixed-dimensional quasi-2D perovskites is crucial for their application in high-performance photovoltaic devices. In this work, we investigate the link between charge transport dynamics and morphology in a thin film of quasi-2D perovskites (PEA2MAn-1PbnI3n+1), grown with a distinct dimensionality gradient, where the n=1 phase is concentrated near the substrate and phases with higher dimensionality progressively increase in concentration toward the surface. By selectively exciting the n=4 phase, we observe efficient hole transfer to the n=2 and n=3 phases occurring within few tens of picoseconds after excitation. In contrast, the n=1 phase acts as a hole-blocking layer, limiting the overall charge transport efficiency. These results emphasize the critical importance of minimizing or eliminating the n=1 layer to enhance charge carrier separation and transport, offering valuable insights into the optimization of quasi-2D perovskite-based solar cells.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Stability of the Mott phase in excitonic double layers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
K. Ziegler, R. Ya. Kezerashvili
We study the stability of excitonic Mott phases in the presence of a periodic potential and a non-local exciton-exciton interaction. The non-local interaction is treated in a mean-field approximation, while the local repulsion of the excitons is treated in a hopping expansion. The convergence of the latter is the criterion for the stability of the Mott phase with respect to quantum and thermal fluctuations. This hybrid approach enables us to establish a phase diagram for a bosonic Mott to superfluid transition. Our results could be useful to interpret recent experiments on electron-hole crystals in van der Waals heterostructures.
Materials Science (cond-mat.mtrl-sci), Quantum Gases (cond-mat.quant-gas)
7 pages, 3 figures
Fully-frustrated octahedral antiferromagnet: emergent complexity in external field
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
A. S. Gubina, T. Ziman, M. E. Zhitomirsky
Octahedral antiferromagnets are distinguished by crystal lattices composed of octahedra of magnetic ions. In the fully frustrated case, the Heisenberg Hamiltonian can be represented as a sum of squares of total spins for each octahedral block. We study the fully frustrated spin model for a lattice of edge-shared octahedra, which corresponds to the J1-J2 fcc antiferromagnet with J2/J1 = 1/2. The magnetization process at this strongly frustrated point features a remarkably rich sequence of different magnetic phases that include fractional plateaus at m = 1/3 and 2/3 values of the total magnetization. By performing extensive Monte Carlo simulations we construct the H-T phase diagram of the classical model with eight field-induced states, which acquire stability via the order by disorder mechanism. These antiferromagnetic states have distinct spin configurations of their octahedral blocks. The same spin configurations are also relevant for the fully frustrated corner-shared model bringing an apparent similarity to their field-induced states.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
8 pages, 6 figures
Microtubes and nanomembranes by ion-beam-induced exfoliation of \(\beta\)-Ga\(_{2}\)O\(_{3}\)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Duarte Magalhães Esteves, Ru He, Calliope Bazioti, Sérgio Magalhães, Miguel Carvalho Sequeira, Luís Filipe Santos, Alexander Azarov, Andrej Kuznetsov, Flyura Djurabekova, Katharina Lorenz, Marco Peres
This paper reports an innovative process to fabricate \(\beta\)-Ga\(_{2}\)O\(_{3}\) microtubes and nanomembranes based on ion implantation in (100)-oriented single-crystals. We show that, under specific flux and fluence conditions, the irradiation-induced strain profile promotes the detachment and rolling-up of a thin surface layer, forming a microtube. The strain-disorder interplay was investigated in detail for Cr-implanted \(\beta\)-Ga\(_{2}\)O\(_{3}\) with a range of complementary methods, showing an excellent agreement between experimental and simulation data, and suggesting an exfoliation mechanism that is correlated with the anisotropic nature of the \(\beta\)-Ga\(_{2}\)O\(_{3}\) monoclinic system and its easy-cleavage planes. Moreover, these microtubes can be unrolled upon a subsequent annealing step, resulting in nanomembranes with bulk-like crystalline quality that can be transferred to other substrates. The recovery of the implantation-induced damage under thermal annealing has also been studied, showing a remarkable recovery at moderate temperatures (~500 °C). This observation underscores the potential of this method for the scalable production of nanomembranes with improved reproducibility compared to conventional mechanical exfoliation techniques. Importantly, such exfoliation can be done employing different ions, providing simultaneous \(\beta\)-Ga\(_{2}\)O\(_{3}\) doping, chosen to control the structural, optical, magnetic and electrical properties of the nanomembranes, thus tailoring them to fit the desired applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
35 pages, 16 figures, 4 tables
Dimensional Crossover and Emergence of Novel Phases in Puckered PdSe\(_2\) under Pressure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-23 20:00 EST
Tanima Kundu, Soumik Das, Koushik Dey, Boby Joseph, Mainak Palit, Sanjoy Kr Mahatha, Kapildeb Dolui, Subhadeep Datta
We investigate the pressure-driven structural and electronic evolution of PdSe(2) using powder X-ray diffraction, Raman spectroscopy, and first-principles calculations. Beyond 2.3 GPa, suppression of the Jahn-Teller distortion induces in-plane lattice expansion and metallization. Around 4.8 GPa, the interlayer (d{z2}-) orbital hybridization drives the dimensional crossover, facilitating the transformation from the 2D distorted to a 3D undistorted pyrite phase. Above 9 GPa, a novel phase emerges, characterized by octahedral distortions in the \(d\) orbitals of Pd. Structural analysis suggests the presence of marcasite ((Pnnm)) or arsenopyrite ((P2_1/c)) phase with orthorhombic and monoclinic configurations, respectively. Furthermore, the observed phonon anomaly and electronic structure modifications, including the emergence of flat bands in the high-pressure phases, elucidate the fundamental mechanisms underlying the previously reported exotic superconductivity with an enhanced critical temperature. These results highlight the pivotal role of dimensional crossover and structural transitions in tuning the electronic properties of puckered materials, providing pathways for novel functionalities.
Materials Science (cond-mat.mtrl-sci)
Bound states and deconfined spinons in the dynamical structure factor of the \(J_1 - J_2\) spin-1 chain
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-23 20:00 EST
Aman Sharma, Mithilesh Nayak, Henrik M. Rønnow, Frédéric Mila
Using a time-dependent density matrix renormalization group approach, we study the dynamical structure factor of the \(J_1 - J_2\) spin-1 chain. As \(J_2\) increases, the magnon mode develops incommensurability. The system undergoes a first-order transition at \(J_2 = 0.76 J_1\), and at that point, domain walls lead to a continuum of fractional quasi-particles or spinons. By studying small variations in \(J_2\) around the transition point, we observe the confinement of spinons into bound states in the spectral function and find a smooth evolution of the spectrum into magnon modes away from the phase transition. We employ the single-mode approximation to accurately account for the dispersion of the magnon mode away from the phase transition and describe the associated continua and bound states. We extend the single-mode approximation to describe the dispersion of a spinon at the phase transition point and obtain its dispersion throughout the Brillouin zone. This allows us to relate the incommensurability at and around the transition point to the competition between a negative nearest-neighbour hopping amplitude and a positive next-nearest-neighbour one for the domain wall.
Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 13 Figures