CMP Journal 2025-04-22
Statistics
Nature: 3
Nature Materials: 1
Nature Physics: 2
Physical Review Letters: 5
Physical Review X: 2
arXiv: 63
Nature
Stereoretentive radical cross-coupling
Original Paper | Homogeneous catalysis | 2025-04-21 20:00 EDT
Jiawei Sun, Jiayan He, Luca Massaro, David A. Cagan, Jet Tsien, Yu Wang, Flynn C. Attard, Jillian E. Smith, Jason S. Lee, Yu Kawamata, Phil S. Baran
Free radicals were first discovered over 120 years ago by Gomberg1 and the first radical cross-couplings demonstrated by Kochi in the 1970’s.2 In contrast to widely employed polar cross-coupling chemistry to forge C(sp2)-C(sp2) bonds (Suzuki, Negishi, Kumada, etc.), radical cross-coupling is advantageous when applied to the coupling of saturated systems due to the mild conditions employed and enhanced chemoselectivity associated with single electron chemistry. Indeed, the ability to employ ubiquitous carbon-based fragments (carboxylic acids, alcohols, amines, olefins, etc.) in cross-coupling has dramatically simplified access to a variety of complex molecules.3-9 Despite these advantages, enantiospecific coupling reactions involving free radicals are unknown and generally believed to be challenging due to their near-instantaneous racemization (picosecond timescale).10 As a result, controlling the stereochemical outcome of radical cross-coupling can only be achieved on a case-by-case basis using bespoke chiral ligands11 or in a diastereoselective fashion guided by nearby stereocenters.12 Here we show how readily accessible enantioenriched sulfonylhydrazides and low loadings of an inexpensive achiral Ni-catalyst can be enlisted to solve this vexing challenge for the first time thereby enabling enantiospecific, stereoretentive radical cross-coupling between enantioenriched alkyl fragments and (hetero)aryl halides without exogenous redox chemistry or chiral ligands. Calculations support the intermediacy of a unique Ni-bound diazene-containing transition state with C-C bond formation driven by loss of N2.
Homogeneous catalysis, Organic chemistry
Substrate recognition and cleavage mechanism of the monkeypox protease, Core protease
Original Paper | Drug discovery | 2025-04-21 20:00 EDT
Yan Gao, Xiong Xie, Xiaoyu Zhang, Junyuan Cao, Weiqi Lan, Tian You, Dongxu Li, Xuxue Dong, Wenhao Dai, Yingchun Xiang, Shulei Hu, Weijuan Shang, Botao Wu, Yumin Zhang, Jin Xu, Xiaoce Liu, Haofeng Wang, Wanlong Hu, Mingjing Zhang, Yinkai Duan, Wen Cui, Hao Zhou, Shengjiang Mao, Handi Jia, Zhanqi Sun, Menghan Jia, Yue Yin, Henry C. Nguyen, Kailin Yang, Bei Yang, Xiuna Yang, Xiaoyun Ji, Gengfu Xiao, Wei Wang, Leike Zhang, Zihe Rao, Hong Liu, Haitao Yang
Poxviruses cause severe diseases including smallpox and mpox, which pose major threats to human health. The poxvirus core protease (CorePro) is essential for viral maturation and highly conserved in poxviruses, making it an attractive antiviral target1. However, the structure of CorePro remains unknown, hampering antiviral development. Here, we determined the structures of mpox virus (MPXV) apo-CorePro and its complex with an inhibitor aloxistatin, which is a drug candidate for muscular dystrophy2. These structures show that CorePro forms a homodimer featuring a unique “dancing-couple” fold. The catalytic intermediate state of CorePro was characterized by an aldehyde derivative from a natural substrate (I-G18). This derivative covalently binds to the catalytic cysteine 328 (Cys328), making the active site of viral protease shift from a closed conformation in the apo-form to a favorable open conformation upon substrate binding. Based on the CorePro-I-G18 complex, we then designed a series of peptidomimetic inhibitors with a nitrile warhead, which could covalently anchor with the catalytic Cys328. These compounds inhibit the CorePro with IC50 values of 44.9-100.3 nM, exhibiting potent and broad anti-poxvirus activity as well. Our studies provide the basis for designing wide-spectrum inhibitors against poxvirus infections.
Drug discovery, Structural biology
Custom CRISPR–Cas9 PAM variants via scalable engineering and machine learning
Original Paper | Genetic engineering | 2025-04-21 20:00 EDT
Rachel A. Silverstein, Nahye Kim, Ann-Sophie Kroell, Russell T. Walton, Justin Delano, Rossano M. Butcher, Martin Pacesa, Blaire K. Smith, Kathleen A. Christie, Leillani L. Ha, Ronald J. Meis, Aaron B. Clark, Aviv D. Spinner, Cicera R. Lazzarotto, Yichao Li, Azusa Matsubara, Elizabeth O. Urbina, Gary A. Dahl, Bruno E. Correia, Debora S. Marks, Shengdar Q. Tsai, Luca Pinello, Suk See De Ravin, Qin Liu, Benjamin P. Kleinstiver
Engineering and characterizing proteins can be time-consuming and cumbersome, motivating the development of generalist CRISPR-Cas enzymes1-4 to enable diverse genome editing applications. However, such enzymes have caveats such as an increased risk of off-target editing3,5,6. To enable scalable reprogramming of Cas9 enzymes, here we combined high-throughput protein engineering with machine learning (ML) to derive bespoke editors more uniquely suited to specific targets. Via structure/function-informed saturation mutagenesis and bacterial selections, we obtained nearly 1,000 engineered SpCas9 enzymes and characterized their protospacer-adjacent motif7 (PAM) requirements to train a neural network that relates amino acid sequence to PAM specificity. By utilizing the resulting PAM ML algorithm (PAMmla) to predict the PAMs of 64 million SpCas9 enzymes, we identified efficacious and specific enzymes that outperform evolution-based and engineered SpCas9 enzymes as nucleases and base editors in human cells while reducing off-targets. An in silico directed evolution method enables user-directed Cas9 enzyme design, including for allele-selective targeting of the RHO P23H allele in human cells and mice. Together, PAMmla integrates ML and protein engineering to curate a catalog of SpCas9 enzymes with distinct PAM requirements, and motivates the use of efficient and safe bespoke Cas9 enzymes instead of generalist enzymes for various applications.
Genetic engineering, Machine learning, Protein design
Nature Materials
Tunable fractional Chern insulators in rhombohedral graphene superlattices
Original Paper | Electronic properties and materials | 2025-04-21 20:00 EDT
Jian Xie, Zihao Huo, Xin Lu, Zuo Feng, Zaizhe Zhang, Wenxuan Wang, Qiu Yang, Kenji Watanabe, Takashi Taniguchi, Kaihui Liu, Zhida Song, X. C. Xie, Jianpeng Liu, Xiaobo Lu
Fractional Chern insulators showing transport effects with fractionally quantized Hall plateaus under zero magnetic field provide opportunities to engineer topological electronics. By construction of a topological flat band with moiré engineering, intrinsic fractional Chern insulators have been observed in twisted MoTe2 and rhombohedral pentalayer graphene superlattices. Here we demonstrate moiré superlattices consisting of rhombohedral hexalayer graphene and hexagonal boron nitride that exhibit both integer and fractional quantum anomalous Hall effects. By tuning electrical and magnetic fields at 0 < ν < 1 (v, moiré filling factor), we have observed phase transitions showing a sign reversal of the Hall resistivity at finite magnetic fields. The fractional Chern insulator state at ν = 2/3 survives in the phase transitions, exhibiting a quantized Hall resistivity across both phases. Finally we have theoretically demonstrated the crucial role of the moiré potential in the formation of flat Chern bands. Our work enriches the family of fractional Chern insulators and can advance the exploration of quasi-particles with fractional charge and non-Abelian anyons.
Electronic properties and materials, Graphene
Nature Physics
Scalable microwave-to-optical transducers at the single-photon level with spins
Original Paper | Quantum information | 2025-04-21 20:00 EDT
Tian Xie, Rikuto Fukumori, Jiahui Li, Andrei Faraon
Microwave-to-optical transduction of single photons will play an essential role in interconnecting future superconducting quantum devices. Various transducers have been developed that couple microwave and optical modes by utilizing nonlinear phenomena such as the Pockels effect and a combination of electromechanical, piezoelectric and optomechanical couplings. However, the limited strength of these nonlinearities necessitates the use of high-quality-factor resonators that can require sophisticated nanofabrication methods. Rare-earth-ion-doped crystals have high-quality atomic resonances that result in effective second-order nonlinearities that are many orders of magnitude stronger than those in conventional materials. Here we use ytterbium-171 ions doped in an YVO4 crystal to implement an on-chip microwave-to-optical transducer. Without an engineered optical cavity, we achieve per-cent-level efficiencies with an added noise referred to the input as low as 1.24(9) photons. We demonstrate the interference of photons originating from two simultaneously operated transducers, enabled by the inherently matching frequencies of the atomic transitions. Our results establish rare-earth-ion-based devices as a competitive platform for transduction and pave the way towards the remote transducer-assisted entanglement of superconducting quantum machines.
Quantum information
Skyrmion bags of light in plasmonic moiré superlattices
Original Paper | Nanophotonics and plasmonics | 2025-04-21 20:00 EDT
Julian Schwab, Alexander Neuhaus, Pascal Dreher, Shai Tsesses, Kobi Cohen, Florian Mangold, Anant Mantha, Bettina Frank, Guy Bartal, Frank-J. Meyer zu Heringdorf, Timothy J. Davis, Harald Giessen
The study of van der Waals heterostructures with an interlayer twist, known as twistronics, has been instrumental in advancing the understanding of many strongly correlated phases, many of which derive from the topology of the physical system. Here we explore the application of the twistronics paradigm in plasmonic systems with a non-trivial topology by creating a moiré skyrmion superlattice using two superimposed plasmonic skyrmion lattices with a relative twist. We measure the complex electric field distribution of the moiré skyrmion superlattice using time-resolved polarimetric photoemission electron microscopy. Our results show that each supercell has very large topological invariants and harbours a skyrmion bag, the size of which is controllable by the twist angle and centre of rotation. Our work indicates how twistronics can enable the creation of various topological features in optical fields and provides a route for locally manipulating electromagnetic field distributions.
Nanophotonics and plasmonics, Sub-wavelength optics, Ultrafast photonics
Physical Review Letters
Qudit Shadow Estimation Based on the Clifford Group and the Power of a Single Magic Gate
Research article | Quantum circuits | 2025-04-21 06:00 EDT
Chengsi Mao, Changhao Yi, and Huangjun Zhu
Shadow estimation is a sample-efficient protocol for learning the properties of a quantum system using randomized measurements, but the current understanding of qudit shadow estimation is quite limited compared with the qubit setting. Here, we clarify the sample complexity of qudit shadow estimation based on the Clifford group, where the local dimension $d$ is an odd prime. Notably, we show that the overhead of qudit shadow estimation over the qubit counterpart is only $\mathcal{O}(d)$, which is independent of the qudit number $n$, although the set of stabilizer states may deviate exponentially from a 3-design with respect to the third moment operator. Furthermore, by adding one layer of magic gates, we propose a simple circuit that can significantly boost the efficiency. Actually, a single magic gate can already eliminate the $\mathcal{O}(d)$ overhead in qudit shadow estimation and bridge the gap from the qubit setting.
Phys. Rev. Lett. 134, 160801 (2025)
Quantum circuits, Quantum information theory, Quantum tomography
Direct Evidence of Multispecies Hydrodynamics in Ignition-Scale Hohlraums
Research article | Indirect drive | 2025-04-21 06:00 EDT
Drew P. Higginson, N. Izumi, M. D. Rosen, P. Volegov, T. Chapman, D. N. Fittinghoff, K. D. Hahn, B. M. Haines, J. Jeet, A. J. Kemp, S. Kerr, O. L. Landen, S. MacLaren, A. J. MacKinnon, J. D. Moody, A. S. Moore, B. L. Reichelt, W. M. Riedel, D. J. Schlossberg, D. J. Strozzi, A. E. Youmans, G. Zimmerman, W. A. Farmer, J. S. Ross, and D. E. Hinkel
A targeted experiment at the National Ignition Facility (NIF) confirms the presence of multispecies hydrodynamics in inertial confinement fusion hohlraums relevant to ignition. The effects are identified by filling the gold hohlraum with a deuterium-tritium (DT) gas mixture instead of helium. As the hohlraum is heated by the NIF lasers, it implodes inward, compressing and heating the DT, which leads to fusion. The resulting DT-fusion neutrons are measured in space, time, yield, angle, and energy. A distinct, peaked, triangular shape in the radial neutron emission profile provides evidence of a ‘’leaky piston’’ effect caused by the interpenetration of DT into the expanding gold. This process reduces the reversibility of DT compression and decreases neutron generation on the temporal trailing edge compared to the leading edge. These results are well described by multispecies hydrodynamics simulations, which reproduce the observed spatial and temporal features, as well as the total neutron yield and angularly resolved energy spectra. In contrast, conventional simulations that use only single-species physics fail to match the experimental data. They overpredict the neutron yield, produce a flatter-than-observed spatial profile, and show excessive emission at late times compared to the experimental measurements.
Phys. Rev. Lett. 134, 165101 (2025)
Indirect drive, Inertial confinement fusion, Nuclear fusion, Neutron imaging, Two-fluid & multi-fluid model
Ion Acoustic Instability Resulting from Suprathermal Electrons Generated by Stimulated Raman Scattering in Laser-Plasma Interactions
Research article | Inertial confinement fusion | 2025-04-21 06:00 EDT
C. Rousseaux, S. D. Baton, K. Glize, L. Lancia, D. Bénisti, G. Sary, and L. Gremillet
Using space-time-resolved Thomson scattering, we investigate experimentally the development of electrostatic waves in a preformed undercritical helium plasma driven by a $1.059\text{ }\text{ }\mathrm{\mu }\mathrm{m}$ laser pulse of $\sim 1.5\text{ }\text{ }\mathrm{ps}$ duration and $\sim {10}^{15–16}\text{ }\mathrm{W}\text{ }{\mathrm{cm}}^{- 2}$ mean intensity. We observe the excitation of intense ion plasma waves (IAWs) over a broad wave number range, distinct from what is expected from stimulated Brillouin scattering or Langmuir decay instability. These IAWs are correlated with the occurrence of backward stimulated Raman scattering (B-SRS) at earlier times but persist much longer than the B-SRS-driven electron plasma waves. Particle-in-cell modeling reveals that they result from an ion acoustic instability triggered by the bulk electrons drifting against the ions to neutralize the current carried by the B-SRS-generated hot electrons. The properties of the simulated unstable IAWs match well with the measurements.
Phys. Rev. Lett. 134, 165102 (2025)
Inertial confinement fusion, Laser-plasma interactions, Plasma instabilities, Stimulated Raman scattering, Particle-in-cell methods, Plasma diagnostic techniques
Robust Chaos in a Totally Symmetric Network of Four Phase Oscillators
Research article | Chaos | 2025-04-21 06:00 EDT
Efrosiniia Karatetskaia, Alexey Kazakov, Klim Safonov, and Dmitry Turaev
The Kuramoto model and its generalizations are universal models of collective behavior in oscillatory networks. We provide conditions on the coupling function such that the Kuramoto system with four globally coupled identical oscillators has chaotic attractors: a pair of Lorenz attractors or a four-winged analog of the Lorenz attractor. The attractors emerge near the triple instability threshold of the splay-phase synchronization state of the oscillators. We provide theoretical arguments and verify numerically, based on the pseudohyperbolicity test, that the chaotic dynamics are robust with respect to small, e.g., time-dependent, perturbations of the system. The robust chaoticity should also be inherited by any network of weakly interacting systems with such attractors.
Phys. Rev. Lett. 134, 167201 (2025)
Chaos, Dynamics of networks, Mathematical physics, Chaotic systems, Collective dynamics, Dynamical systems
Surfactant Exchanges between Deformed Soap Films
Research article | Surface tension effects | 2025-04-21 06:00 EDT
Théo Lenavetier, Emmanuel Schaub, and Isabelle Cantat
The effective viscosity of liquid foams is controlled by Marangoni forces and therefore by the transport of surfactants. Direct tracking of the latter during foam deformation is out of reach. Besides, the competition between diffusion and convection on the interfaces and in the bulk of complex assemblies of thin films and menisci is still an open problem. These shortcomings severely limit our understanding of foam rheology and stability. In this Letter, we use a comprehensive characterization of in-plane flows in an elementary foam during imposed deformation to determine indirectly the flux of surfactants from a film to its first neighbor. We show that the meniscus connecting the films, despite its potential role as a surfactant reservoir, is not involved in surfactant transport. This information has been identified as a key missing piece in local foam viscosity models of the literature.
Phys. Rev. Lett. 134, 168201 (2025)
Surface tension effects, Transport phenomena, Foams, Gas-liquid interfaces, Surfactant monolayers
Physical Review X
Pulling Order Back from the Brink of Disorder: Observation of a Nodal-Line Spin Liquid and Fluctuation Stabilized Order in ${\mathrm{K}}{2}{\mathrm{IrCl}}{6}$
Research article | Frustrated magnetism | 2025-04-21 06:00 EDT
Qiaochu Wang, Alberto de la Torre, Jose A. Rodriguez-Rivera, Andrey A. Podlesnyak, Wei Tian, Adam A. Aczel, Masaaki Matsuda, Philip J. Ryan, Jong-Woo Kim, Jeffrey G. Rau, and Kemp W. Plumb
The discovery of a nodal-line spin-liquid phase in a frustrated magnet shows how fluctuations in such materials can act counterintuitively to protect an ordered magnetic moment.
Phys. Rev. X 15, 021021 (2025)
Frustrated magnetism, Spin liquid, Antiferromagnets, Neutron scattering
Unitary $k$-Designs from Random Number-Conserving Quantum Circuits
Research article | Information scrambling | 2025-04-21 06:00 EDT
Sumner N. Hearth, Michael O. Flynn, Anushya Chandran, and Chris R. Laumann
Symmetry-constrained random quantum circuits generate randomness more slowly than unconstrained ones, following a diffusive process. This finding reveals how conservation laws can impact quantum simulation and computation.
Phys. Rev. X 15, 021022 (2025)
Information scrambling, Quantum information processing, Quantum information theory, Disordered systems, Lattice models in statistical physics, Chaos & nonlinear dynamics, Random matrix theory
arXiv
Maze-Bubble Pattern Magnetic Domain Simulation Based on the Lengyel-Epstein Model
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
This study is based on the Lengyel-Epstein (LE) model, governed by a system of nonlinear partial differential equations, to simulate the maze-bubble pattern magnetic domains in magnetic thin films with perpendicular magnetic anisotropy (PMA). Through numerical simulations, we successfully reproduce the maze, bubble, and intermediate-state magnetic domains observed in PMA multilayer films under the influence of material thickness and external magnetic fields. The topological structures of the magnetic domains shown in the simulation closely resemble those observed under a microscope, demonstrating the effectiveness of the LE model in simulating changes in the magnetic domain topology of magnetic thin films. This study also innovatively applies the concept of reaction-diffusion, commonly used in biochemistry, by drawing an analogy to electromagnetism. This approach holds significant implications for the study of magnetic domains.
Materials Science (cond-mat.mtrl-sci), Analysis of PDEs (math.AP)
Ensemble Inequivalence in long range interacting spin systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
Daniel Arrufat-Vicente, David Mukamel, Stefano Ruffo, Nicolo Defenu
Ensemble inequivalence occurs when a systems thermodynamic properties vary depending on the statistical ensemble used to describe it. This phenomenon is known to happen in systems with long-range interactions and has been observed in many classical systems. In this study, we provide a detailed analysis of a long-range quantum ferromagnet spin model that exhibits ensemble inequivalence. At zero temperature ($ T = 0$ ), the microcanonical phase diagram matches that of the canonical ensemble. However, the two ensembles yield different phase diagrams at finite temperatures. This behavior contrasts with the conventional understanding in statistical mechanics of systems with short-range interactions, where thermodynamic properties are expected to align across different ensembles in the thermodynamic limit. We discuss the implications of these findings for synthetic quantum long-range platforms, such as atomic, molecular, and optical (AMO) systems.
Statistical Mechanics (cond-mat.stat-mech)
Edge-prompted spin waves probed via magneto-optical effect in the infrared
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Junming Wu, Dinesh Wagle, Yuzan Xiong, Andrew Christy, Yi Li, Shihao Zhou, James F. Cahoon, Xufeng Zhang, M. Benjamin Jungfleisch, Wei Zhang
Recent advances in magnonics highlight the need for employing spin wave characteristics as new state variables, which is to be detected and mapped out with high precision in all-onchip, small scale devices. Spin wave modes that are prompted by the sample edges in planar structures are of particular fundamental importance to the future design and characterization of magnonic device functionalities. In this work, we demonstrate an infrared light-based, magneto-optical technique that concurrently functions both as a spectroscopic and an imaging tool. The detected precessional phase contrast can be directly used to construct the map of the spin wave wavefront in the continuous wave regime of spin-wave propagation and in the stationary state, without needing any optical reference path. We experimentally detect the edge spin wave modes of a Y3Fe5O12 film sample, and study the evolution and interference from edge dominated modes to their bulk counterparts. Distinct wavevector groups and propagation characteristics are observed for the edge and bulk spin wave modes. Further, the magnon dispersion relation in the infrared is obtained by Fourier transforming the wavefronts measured in real space, which is a huge advantage to the wavevector-resolved Brillouin light scattering (BLS) technique, where the angle of incidence has to be varied, and is also much less cumbersome than the phase-resolved BLS. Our results demonstrate that the infrared optical strobe light can serve as a versatile platform for magneto-optical probing of magnetization dynamics, with potential implications in investigating hybrid magnonic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
IEEE Nano 2025
Micromagnetic-atomistic hybrid modeling of defect-induced magnetization dynamics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Nastaran Salehi, Olle Eriksson, Johan Hellsvik, Manuel Pereiro
This study presents a multiscale approach for investigating magnetization dynamics in multiscale, hybrid micromagnetic-atomistic simulations. We considered the dynamics of spin waves, domain walls, as well as three-dimensional (3D) skyrmions, in the presence of defects. Two primary defect configurations are examined: (i) a double-slit structure, which enables the study of domain wall and spin wave interference, and (ii) a tetrahedron shaped cluster of atoms with tunable anisotropy, which provides insights into how localized anisotropic perturbations influence domain wall pinning and skyrmion stability. The magnonic double-slit experiment demonstrates interference patterns analogous to electronic wave phenomena, offering potential applications in wave-based computing. Additionally, the results reveal the impact of the local anisotropy that leads to distinct transformations, including domain wall deformations, tubular and spherical structures, skyrmion annihilation, and breathing mode. The findings underscore the critical role of defect-induced anisotropic interactions in controlling domain wall motion, skyrmion topology, and spin wave propagation.
Materials Science (cond-mat.mtrl-sci)
29 pages, 27 figures, 1 table
Kinetic analysis of phase transformations during continuous heating: Crystallization of glass-forming liquids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Phase transformations are widely studied using continuous-heating experiments. In isothermal studies, their kinetics are often described using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) rate equation. For continuous-heating studies, the same analysis has only been applied numerically. Here, a JMAK rate equation for phase transformations during continuous heating is derived. The equation is applied to the crystallization of glass-forming liquids with different kinetic behaviors and validated by comparison to experimental data and numerical simulations for the crystallization of glassy $ \rm Fe_{80}B_{20}$ (at.%). Kissinger’s method of analyzing crystallization kinetics is subsequently justified, and it is shown that the non-Arrhenius temperature dependence of crystal growth rates in glass-forming liquids can be better determined by using the present model to fit the peak position, shape and height for a series of crystallization exotherms. The implications of these analytical expressions for the design and development of glass-forming systems for a broad range of applications are considered, and the application of this JMAK rate equation to other transformations during continuous heating is explored.
Materials Science (cond-mat.mtrl-sci)
Modulation doping and control the carrier concentration in 2-dimensional transition metal dichalcogenides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Two-dimensional transition-metal dichalcogenides (TMDs) have attracted interest as post-Si channel candidates in transistor technology. However, despite their potential benefits, controllably doping TMDs has proven difficult. In this work, we proposed a list of candidate elements that can induce p-type and n-type doping in the TMD channel when they are doped onto conventional gate-dielectric oxides. To verify the screened modulation doping candidates, we demonstrate using first-principles calculations the p-doping of monolayer WSe$ _2$ by doping Ni int\textbf{}o the interface dielectric HfO$ _2$ layer. The induced hole concentration in the WSe$ _2$ can be tuned to values compatible with electrostatic gate control of the channel by changing the Ni doping rate. The results of this study will have essential implications for the commercial viability of TMD-based transistors.
Materials Science (cond-mat.mtrl-sci)
Interfacial Effects and Negative Capacitance State in P(VDF-TrFE) Films with BaTiO3 Nanoparticles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Oleksii V. Bereznykov, Oleksandr S. Pylypchuk, Victor I. Styopkin, Serhii E. Ivanchenko, Denis O. Stetsenko, Eugene A. Eliseev, Zdravko Kutnjak, Vladimir N. Poroshin, Anna N. Morozovska, Nicholas V. Morozovsky
We analyze the temperature dependences of the effective dielectric permittivity of P(VDF-TrFE) films with BaTiO3 nanoparticles (with the average size 24 nm). Transition from a weak to a strong nonlinear temperature dependence of the dielectric permittivity is observed near the freezing temperature (near -50 °C) of P(VDF-TrFE). The transition is followed by a diffuse step-like change in the temperature range (0 - 40)°C, and a subsequent maximum of the dielectric permittivity in the P(VDF-TrFE) films with a lower content (20-40 vol.%) of BaTiO3 nanoparticles; or by a quasi-plateau of the dielectric permittivity in the P(VDF-TrFE) films with a higher content ( 50-70 vol.%) of BaTiO3 nanoparticles. The frequency dispersion of the dielectric permittivity is significant in the vicinity of its maxima. The temperature-frequency shift of the permittivity region with a strong temperature dependence is positive. The temperature-frequency shift of the maxima is insignificant (or negative) for the P(VDF-TrFE) films with lower content of BaTiO3 nanoparticles. Increasing the content of BaTiO3 nanoparticles leads to a significant increase in the relative dielectric permittivity of the P(VDF-TrFE)-BaTiO3 films compared to pure P(VDF-TrFE) films (from 8 to 50 at 25 °C). At the same time, the voltage response of the studied P(VDF-TrFE)/BaTiO3 films to the frequency-modulated IR radiation flux has rather photoelectric than pyroelectric nature. A phenomenological model, which considers the screening charges at the interfaces, as well as dipole-dipole cross-interaction effects between the ferroelectric nanoparticles, is proposed to describe the temperature and frequency behavior of the effective dielectric permittivity. The negative capacitance state, which originates due to the interfacial effects, is predicted in the P(VDF-TrFE) films with a high content of BaTiO3 nanoparticles.
Materials Science (cond-mat.mtrl-sci)
42 pages, 10 figures, 1 appenndix
System of Agentic AI for the Discovery of Metal-Organic Frameworks
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Theo Jaffrelot Inizan, Sherry Yang, Aaron Kaplan, Yen-hsu Lin, Jian Yin, Saber Mirzaei, Mona Abdelgaid, Ali H. Alawadhi, KwangHwan Cho, Zhiling Zheng, Ekin Dogus Cubuk, Christian Borgs, Jennifer T. Chayes, Kristin A. Persson, Omar M. Yaghi
Generative models and machine learning promise accelerated material discovery in MOFs for CO2 capture and water harvesting but face significant challenges navigating vast chemical spaces while ensuring synthetizability. Here, we present MOFGen, a system of Agentic AI comprising interconnected agents: a large language model that proposes novel MOF compositions, a diffusion model that generates crystal structures, quantum mechanical agents that optimize and filter candidates, and synthetic-feasibility agents guided by expert rules and machine learning. Trained on all experimentally reported MOFs and computational databases, MOFGen generated hundreds of thousands of novel MOF structures and synthesizable organic linkers. Our methodology was validated through high-throughput experiments and the successful synthesis of five “AI-dreamt” MOFs, representing a major step toward automated synthesizable material discovery.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI), Computation and Language (cs.CL), Multiagent Systems (cs.MA)
Charge Densities in Crystals and Triply-Periodic Minimal Surfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Mengdi Yin, Dimitri D. Vvedensky
The relationship between surfaces of constant charge density and triply-periodic minimal surfaces (TPMS) has been the subject of considerable speculation over many years. Zero-potential surfaces generated in crystals by an electrostatic field from a distribution of point charges provide an approximate description of the TPMS for that crystal. We have recently provided a first-principles alternative to such phenomenological comparisons based on the Vienna ab initio simulation package (VASP). We showed that the surfaces of a zero charge density calculated for the crystal structure of a material converges to the TPMS of the corresponding crystalline material. The exchange-correlation potentials are chosen for the particular material based on the benchmarking of various approximations for these potentials carried out by others. Here, we report an extension of our previous work by giving additional examples of our theory that shows the zero electron density of an equilibrium structure corresponds to a TPMS for a variety of materials and crystalline structures. We study the ground states of elemental materials that differ electronically and structurally, Na, Cu, Al, Zr, and a compound, NiTi, as well as different phases of the elemental solids that are observed under different thermodynamic conditions.
Materials Science (cond-mat.mtrl-sci)
Probing Loop Currents and Collective Modes of Charge Density Waves in Kagome Materials with NV Centers
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-22 20:00 EDT
Recently, the unconventional charge density wave (CDW) order with loop currents has attracted considerable attention in the Kagome material family AV$ _3$ Sb$ _5$ (A = K, Rb, Cs). However, experimental signatures of loop current order remain elusive. In this work, based on the mean-field free energy, we analyze the collective modes of unconventional CDW order in a Kagome lattice model. Furthermore, we point out that phase modes in the imaginary CDW (iCDW) order with loop current orders result in time-dependent stray fields. We thus propose using nitrogen-vacancy (NV) centers to detect these time-dependent stray fields, providing a potential experimental approach to identifying loop current order.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 3 figures, plus Supplementary Material
General Phase Segregation and Phase Pinning Effects in Ln-doped Lead Halide Perovskite with Dual-wavelength Lasing
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Junyu He, Jun Luo, Weihao Zheng, Biyuan Zheng, Mengjian Zhu, Jiahao Liu, Tingzhao Fu, Jing Wu, Zhihong Zhu, Fang Wang, Xiujuan Zhuang
Lead halide perovskites (LHPs) exhibit outstanding optoelectronic properties, making them highly promising for applications in various optoelectronics devices. However, rapid ion migration in LHPs not only undermines device stability but also hinders the development of multi-band composite structures, which are crucial to advancing perovskite bandgap engineering and unlocking novel applications. Here, we introduce a novel and general strategy involving both phase segregation and phase pinning by doping Er$ ^{3+}$ into CsPb(X$ _x$ Y$ _{1-x}$ )$ _3$ (X, Y = Cl, Br, I) microplates via a simple one-step chemical vapor deposition method. The ion migration is effectively suppressed and a variety of stable multi-band composite structures are demonstrated, with diverse dual-band photoluminescence emissions covering the red, green, and blue spectral bands. The corresponding high-performance dual-wavelength lasers have also been fabricated, confirming the stability and high crystalline quality of these multi-band composite structures. In addition, this strategy is extended to the doping of various lanthanide ion and the incorporation of different mixed halides into LHPs. As a result, a series of multi-band composite structures based on LHPs and corresponding dual-wavelength lasers are developed, thereby validating the generality of this strategy. Theoretical calculations clarify the phase segregation and phase pinning mechanism in these LHPs. Our work not only facilitates the stability design of LHPs but also significantly advances the bandgap engineering, thereby contributing to the expansion of their potential applications in the optoelectronic future.
Materials Science (cond-mat.mtrl-sci)
22 pages, 5 figures
Retrieval of fundamental material parameters of monolayer transition metal dichalcogenides from experimental exciton energies: An analytical approach
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Duy-Nhat Ly, Dai-Nam Le, Dang-Khoa D. Le, Van-Hoang Le
We propose a straightforward and highly accurate method for determining material parameters such as screening length, bandgap energy, exciton reduced mass, and dielectric constant of the surrounding medium using experimental magnetoexciton energies available for monolayer transition metal dichalcogenides (TMDCs). Our approach is based on analytical formulations that allow us to calculate the screening length $ r_0$ and bandgap energy $ E_g$ directly from the experimental $ s$ -state exciton energies $ E_{1s}$ , $ E_{2s}$ , and $ E_{3s}$ . We also establish a relationship between the surrounding dielectric constant $ \kappa$ and the exciton reduced mass $ \mu$ . This relationship simplifies the Schr{ö}dinger equation for a magnetoexciton in a TMDC monolayer, transforming it into a one-parameter equation that depends only on a single material parameter, $ \mu$ . Therefore, the fitting method is easy to implement, as it compares calculated magnetoexciton energies with experimental data to determine the true exciton reduced mass, the best-fit value of $ \mu$ . By applying this method, we extract material parameters $ E_g$ , $ r_0$ , $ \mu$ , and $ \kappa$ from the magnetoexciton energies of monolayer TMDCs (WSe$ _2$ , WS$ _2$ , MoSe$ _2$ , and MoS$ _2$ ) encapsulated by hexagonal boron nitride (hBN) slabs in various current experiments. Additionally, we provide key material properties such as diamagnetic coefficients and exciton radii, which are calculated using the extracted parameters.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph)
8 pages, 5 figures, 2 tables. Submitted to Physical Review B
Bacteria exploit torque-induced buckling instability for flagellar wrapping
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-22 20:00 EDT
Takuro Kataoka, Taiju Yoneda, Daisuke Nakane, Hirofumi Wada
Recent advances in microscopy techniques has uncovered unique aspects of flagella-driven motility in bacteria. A remarkable example is the discovery of flagellar wrapping, a phenomenon whereby a bacterium wraps its flagellum (or flagellar bundle) around its cell body and propels itself like a corkscrew, enabling locomotion in highly viscous or confined environments. For certain bacterial species, this flagellar-wrapping mode is crucial for establishing selective symbiotic relationships with their hosts. The transformation of a flagellum from an extended to a folded (wrapped) state is triggered by a buckling instability driven by the motor-generated torque that unwinds the helical filament. This study investigated this biologically inspired, novel buckling mechanism through a combination of macroscale physical experiments, numerical simulations, and scaling theory to reveal its underlying physical principles. Excellent quantitative agreement between experiments and numerical results showed that long-range hydrodynamic interactions (HIs) are essential for accurate quantitative descriptions of the geometrically nonlinear deformation of the helical filament during wrapping. By systematically analyzing extensive experimental and numerical data, we constructed a stability diagram that rationalized the stability boundary through an elastohydrodynamic scaling analysis. Leveraging the scaling nature of this study, we compared our physical results with available biological data and demonstrated that bacteria exploit motor-induced buckling instability to initiate their flagellar wrapping. Our findings indicate that this mechanically-driven process is essential to bacterial-wrapping motility and consequently, plays a critical role in symbiosis and infection.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
9 pages, 6 figures, plus SI 9 pages, 7 figures
Fabrication and characterization of boron-terminated tetravacancies in monolayer hBN using STEM, EELS and electron ptychography
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Dana O. Byrne, Stephanie M. Ribet, Demie Kepaptsoglou, Quentin M. Ramasse, Colin Ophus, Frances I. Allen
Tetravacancies in monolayer hexagonal boron nitride (hBN) with consistent edge termination (boron or nitrogen) form triangular nanopores with electrostatic potentials that can be leveraged for applications such as selective ion transport and neuromorphic computing. In order to quantitatively predict the properties of these structures, an atomic-level understanding of their local electronic and chemical environments is required. Moreover, robust methods for their precision manufacture are needed. Here were use electron irradiation in a scanning transmission electron microscope (STEM) at high dose rate to drive the formation of boron-terminated tetravacancies in monolayer hBN. Characterization of the defects is achieved using aberration-corrected STEM, monochromated electron energy-loss spectroscopy (EELS), and electron ptychography. Z-contrast in STEM and chemical fingerprinting by core-loss EELS enable identification of the edge terminations, while electron ptychography gives insight into structural relaxation of the tetravacancies and provides evidence of enhanced electron density around the defect perimeters indicative of bonding effects.
Materials Science (cond-mat.mtrl-sci)
Bulk photogalvanic current control and gap spectroscopy in 2D hexagonal materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Two-dimensional (2D) hexagonal materials have been intensively explored for multiple optoelectronic applications such as spin current generation, all-optical valleytronics, and topological electronics. In the realm of strong-field and ultrafast light-driven phenomena, it was shown that tailored laser driving such as polychromatic or few-cycle pulses can drive robust bulk photogalvanic (BPG) currents originating from the K/K’ valleys. We here explore the BPG effect in 2D systems in the strong-field regime and show that monochromatic elliptical pulses also generically generate such photocurrents. The resultant photocurrents exhibit both parallel and transverse (Hall-like) components, both highly sensitive to the laser parameters, providing photocurrent control knobs. Interestingly, we show that the photocurrent amplitude has a distinct behavior vs. the driving ellipticity that can be indicative of material properties such as the gap size at K/K’, which should prove useful for novel forms of BPG-based spectroscopies. We demonstrate these effects also in benchmark ab-initio simulations in monolayer hexagonal boron-nitride. Our work establishes new paths for controlling photocurrent responses in 2D systems that can also be used for multi-dimensional spectroscopy of ultrafast material properties through photocurrent measurements.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Wave characteristics and anisotropic homogenization theory of soft matters layered structure
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-22 20:00 EDT
Rui.Guo, Kai Zhang, Nicholas X. Fang
We investigate in this work the wave characteristics and homogenization theory of soft matter layered structure in the limit of low-frequency P-wave. Using the method of potentials, we derive closed-form dispersion relationship and identify three distinct modes of the soft matter layered structure: quasistatic mode, resonance mode, and slip mode. These modes differ based on their equivalent interface conditions: a continuous interface for quasistatic mode, a spring-like interface for resonance mode, and a slip like interface for slip mode. Additionally, we propose a simplified model capturing P-wave wave characteristics in the S-wave high-frequency regime. Our findings unify wave-structure relationships across solid, liquid, and soft matter composites, offering a predictive framework for engineering metamaterials with programmable wave responses. This study offers new insight on the fundamental understanding of layered media and providing direct design principles for applications in acoustic cloaking, vibration damping, and biomedical imaging.
Soft Condensed Matter (cond-mat.soft)
10 pages, 4 figures
Dichotomy theorem distinguishing non-integrability and the lowest-order Yang-Baxter equation for isotropic spin chains
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
Naoto Shiraishi, Mizuki Yamaguchi
We investigate the integrability and non-integrability of isotropic spin chains with nearest-neighbor interaction with general spin $ S$ . We prove a dichotomy theorem that a single relation sharply separates two scenarios: (i) this system is non-integrable, or (ii) the lowest-order Yang-Baxter equation is satisfied. This result solves in the affirmative the Grabowski-Mathieu conjecture stating that a model is integrable only if this model has a 3-local conserved quantity. This theorem also serves as a complete classification of integrability and non-integrability for $ S\leq 13.5$ , suggesting that all the integrable models are in the scope of the Yang-Baxter equation.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), Mathematical Physics (math-ph), Exactly Solvable and Integrable Systems (nlin.SI), Quantum Physics (quant-ph)
7 pages + 14 pages, 1 figure
The Role of Flexoelectric Coupling and Chemical Strains in the Emergence of Polar Chiral Nano-Structures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Anna N. Morozovska, Salia Cherifi-Hertel, Eugene A. Eliseev, Victoria V. Khist, Riccardo Hertel, Dean R. Evans
This review examines the conditions that lead to the formation of flexo-sensitive chiral polar structures in thin films and core-shell ferroelectric nanoparticles. It also analyzes possible mechanisms by which the flexoelectric effect impacts the polarization structure in core-shell ferroelectric nanoparticles. Special attention is given to the role of the anisotropic flexoelectric effect in forming a unique type of polarization states with distinct chiral properties, referred to as “flexons”. In the first part of the review, we study the influence of the flexoelectric coupling on the polarity, chirality and branching of metastable labyrinthine domain structures in uniaxial ferroelectric core-shell nanoparticles. We reveal that the transition from sinuous branched domain stripes to spiral-like domains occurs gradually as the flexoelectric coupling strength is increased. Our findings indicate that the joint action of flexoelectric effect and chemical strains, termed as “flexo-chemical” coupling, can significantly influence the effective Curie temperature, polarization distribution, domain morphology, and chirality in multiaxial ferroelectric core-shell nanoparticles. Furthermore, we demonstrate that the combination of flexo-chemical coupling and screening effects leads to the appearance and stabilization of a chiral polarization morphology in nanoflakes of van der Waals ferrielectrics. In the second part of the review, we discuss several advanced applications of flexo-sensitive chiral polar structures in core-shell ferroelectric nanoparticles for nanoelectronics elements and cryptography. We underline the possibilities of the flexoelectric control of multiple-degenerated labyrinthine states, which may correspond to a differential negative capacitance (NC) state stabilized in the uniaxial ferroelectric core by the presence of a screening shell.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
37 pages, 9 figures. To be submitted to the Journal of Applied Physics “Special Topic on Ferroic Materials, Domains, and Domain Walls: Bridging Fundamentals with Next-Generation Technology”
General trends of electronic structures, superconducting pairing, and magnetic correlations in the Ruddlesden-Popper nickelate $m$-layered superconductors La${m+1}$Ni${m}$O$_{3m+1}$
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-22 20:00 EDT
Yang Zhang, Ling-Fang Lin, Adriana Moreo, Satoshi Okamoto, Thomas A. Maier, Elbio Dagotto
We report a comprehensive theoretical analysis of the Ruddlesden-Popper layered nickelates La$ {m+1}$ Ni$ m$ O$ {3m+1}$ ($ m = 1$ to 6) under pressure. Our results suggest that, while these Ruddlesden-Popper layered nickelates display many similarities, they also show noticeable differences. The Ni $ d{3z^2-r^2}$ orbitals display bonding-antibonding, or bonding-antibonding-nonbonding, characteristic splittings, depending on the even or odd number of stacking layers $ m$ . In addition, the ratio of the in-plane interorbital hopping between $ d{3z^2-r^2}$ and $ d{x^2-y^2}$ orbitals and in-plane intraorbital hopping between $ d_{x^2-y^2}$ orbitals was found to be large in La$ _{m+1}$ Ni$ _m$ O$ _{3m+1}$ ($ m = 1$ to 6), and this ratio increases from $ m = 1$ to $ m = 6$ , suggesting that the in-plane hybridization will increase as the layer number $ m$ increases. In contrast to the dominant $ s^\pm$ –wave state driven by spin fluctuations in the bilayer La$ _3$ Ni$ _2$ O$ _7$ and trilayer La$ _4$ Ni$ _3$ O$ {10}$ , two nearly degenerate $ d{x^2-y^2}$ -wave and $ s^\pm$ -wave leading states were obtained in the four-layer stacking La$ _5$ Ni$ _4$ O$ _{13}$ and five-layer stacking La$ _6$ Ni$ _5$ O$ _{16}$ . The leading $ s^\pm$ -wave state was recovered in the six-layer material La$ _7$ Ni$ _6$ O$ _{19}$ . In general, at the level of the random phase approximation treatment, the superconducting transition temperature $ T_c$ decreases in stoichiometric bulk systems from the bilayer La$ _3$ Ni$ _2$ O$ _7$ to the six-layer La$ _7$ Ni$ _6$ O$ _{19}$ , despite the $ m$ dependent dominant pairing. Both in-plane and out-of-plane magnetic correlations are found to be quite complex. Within the in-plane direction, we obtained the peak of the magnetic susceptibility at $ {\bf q} = (0.6 \pi, 0.6 \pi)$ for La$ _5$ Ni$ _4$ O$ _{13}$ and La$ _7$ Ni$ _6$ O$ _{19}$ , and at $ {\bf q} = (0.7 \pi, 0.7 \pi)$ for La$ _6$ Ni$ _5$ O$ _{16}$ .
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Mechanical properties of B12-based orthorhombic metal carboborides. A first principle study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Oleksiy Bystrenko (1 and 3), Tianxing Sun (1 and 2), Zhaohua Luo (1 and 2), Jingxian Zhang (1 and 2), Yusen Duan (1 and 2), Kaiqing Zhang (1 and 2), Hu Ruan (1 and 2), Wenyu Tang (1 and 2), Bohdan Ilkiv (3), Svitlana Petrovska (3), Tetiana Bystrenko (3) ((1) Shanghai Institute of Ceramics of Chinese Academy of Sciences, Shanghai, China, (2) University of Chinese Academy of Sciences, Beijing, China, (3) Frantsevich Institute for Problems of Materials Science, Kyiv, Ukraine)
Structural and mechanical properties of B12-based orthorhombic metal carboborides are studied on the basis of first principle DFT approach. The simulations predict the existence of a new family of phases of the composition MeC2B12 (Me=Mg, Ca, Sr, Sc, Y) with similar structure and space symmetry Imma. It has been found that the predicted phases are thermally (dynamically) stable and have considerably better mechanical properties as compared to the reference compound AlMgB14. The respective calculated isotropic elastic moduli and Vickers hardness are significantly higher (G~ 230-250, E530-550, and Hv35-55 GPa). These conclusions were confirmed by direct calculations of shear strength for the above phases, which demonstrated the increase of 30-50% in different directions. The enhanced mechanical characteristics of the MgC2B12 -based phases make them promising for creating novel superhard materials
Materials Science (cond-mat.mtrl-sci)
14 pages, 10 figures
Real Space Visualization of Order-Disorder Transition in BaTiO3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Yang Zhang, Xiaoming Shi, Suk Hyun Sung, Cong Li, Houbing Huang, Pu Yu, Ismail El Baggari
Ferroelectricity in BaTiO3 was observed nearly eighty years ago, but the mechanism underlying its ferroelectric-paraelectric phase transition remains elusive. The order-disorder transition has been recognized as playing a critical role, however, the precise nature of the order parameter still remains under scrutiny, including the local dipole direction and the correlations above and below the Curie temperature. Using in situ scanning transmission electron microscopy, we directly map polar displacements in BaTiO3 across the ferroelectric-paraelectric phase transition, providing atomistic insights into a order-disorder mechanism. Atomic tracking reveals finite polar Ti displacements in the paraelectric phase where they manifest as random polar nanoregions. The displacements align along <111> direction in both the ferroelectric and paraelectric phases. The paraelectric-ferroelectric transition emerges from real-space correlations of the <111> polar Ti displacements. Our direct visualizations provides atomic insights into the order-disorder mechanism in the ferroelectric-paraelectric transition of BaTiO3.
Materials Science (cond-mat.mtrl-sci)
Machine learning enhanced atom probe tomography analysis: a snapshot review
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Yue Li, Ye Wei, Alaukik Saxena, Markus Kühbach, Christoph Freysoldt, Baptiste Gault
Atom probe tomography (APT) is a burgeoning characterization technique that provides compositional mapping of materials in three-dimensions at near-atomic scale. Since its significant expansion in the past 30 years, we estimate that one million APT datasets have been collected, each containing millions to billions of individual ions. Their analysis and the extraction of microstructural information has largely relied upon individual users whose varied level of expertise causes clear and documented bias. Current practices hinder efficient data processing, and make challenging standardization and the deployment of data analysis workflows that would be compliant with FAIR data principles. Over the past decade, building upon the long-standing expertise of the APT community in the development of advanced data processing or data mining techniques, there has been a surge of novel machine learning (ML) approaches aiming for user-independence, and that are efficient, reproducible, and robust from a statistics perspective. Here, we provide a snapshot review of this rapidly evolving field. We begin with a brief introduction to APT and the nature of the APT data. This is followed by an overview of relevant ML algorithms and a comprehensive review of their applications to APT. We also discuss how ML can enable discoveries beyond human capability, offering new insights into the mechanisms within materials. Finally, we provide guidance for future directions in this domain.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
$Σ$-Attention: A Transformer-based operator learning framework for self-energy in strongly correlated systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-22 20:00 EDT
Yuanran Zhu, Peter Rosenberg, Zhen Huang, Hardeep Bassi, Chao Yang, Shiwei Zhang
We introduce $ \Sigma$ -Attention, a Transformer-based operator-learning framework to address a key computational challenge in correlated materials. Our approach utilizes an Encoder-Only Transformer as an ansatz to approximate the self-energy operator of strongly correlated electronic systems. By creating a batched dataset that combines results from three complementary approaches: many-body perturbation theory, strong-coupling expansion, and exact diagonalization, each effective in specific parameter regimes, $ \Sigma$ -Attention is applied to learn a universal approximation for the self-energy operator that is valid across all regimes. This hybrid strategy leverages the strengths of existing methods while relying on the transformer’s ability to generalize beyond individual limitations. More importantly, the scalability of the Transformer architecture allows the learned self-energy to be extended to systems with larger sizes, leading to much improved computational scaling. Using the 1D Hubbard model, we demonstrate that $ \Sigma$ -Attention can accurately predict the Matsubara Green’s function and hence effectively captures the Mott transition at finite temperature. Our framework offers a promising and scalable pathway for studying strongly correlated systems with many possible generalizations.
Strongly Correlated Electrons (cond-mat.str-el)
Quantum tomography of the superfluid-insulator transition for a mesoscopic atomtronic ring
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
We provide a phase-space perspective for the analysis of the superfluid-insulator transition for finite-size Bose-Hubbard circuits. We explore how the eigenstates parametrically evolve as the inter-particle interaction is varied, paying attention to the fingerprints of chaos at the quantum phase-transition. Consequently, we demonstrate that the tomographic spectrum reflects the existence of mixed-regions of chaos and quasi-regular motion in phase-space. This tomographic semiclassical approach is much more efficient and informative compared to the traditional ``level statistics” inspection. Of particular interest is the characterization of the fluctuations that are exhibited by the many-body eigenstates. In this context, we associate with each eigenstate a Higgs measure for the identification of amplitude modes of the order-parameter. Finally we focus on the formation of the lowest Goldstone and Higgs bands.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
23 pages, 22 figures
Multifractional Brownian motion with telegraphic, stochastically varying exponent
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
Michał Balcerek, Samudrajit Thapa, Krzysztof Burnecki, Holger Kantz, Ralf Metzler, Agnieszka Wyłomańska, Aleksei Chechkin
The diversity of diffusive systems exhibiting long-range correlations characterized by a stochastically varying Hurst exponent calls for a generic multifractional model. We present a simple, analytically tractable model which fills the gap between mathematical formulations of multifractional Brownian motion and empirical studies. In our model, called telegraphic multifractional Brownian motion, the Hurst exponent is modelled by a smoothed telegraph process which results in a stationary beta distribution of exponents as observed in biological experiments. We also provide a methodology to identify our model in experimental data and present concrete examples from biology, climate and finance to demonstrate the efficacy of our approach.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
A Review on the Applications of Density Functional Theory to the FQH System
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-22 20:00 EDT
Yi Yang, Yayun Hu, Zi-Xiang Hu
The fractional quantum Hall (FQH) effect remains a captivating area in condensed matter physics, characterized by strongly correlated topological order, fractionalized excitations, and anyonic statistics. Numerical simulations, such as exact diagonalization, density matrix renormalization group, matrix product states, and Monte Carlo methods, are essential to examine the properties of strongly correlated systems. Recently, density functional theory (DFT) has been employed in this field within the framework of composite fermion (CF) theory. In this paper, we assess how DFT addresses major challenges in FQH system, such as computing ground state and low-energy excitations. We emphasize the critical insights provided by DFT-based methods into the CF model, edge effects, and the nature of fractional charge and magnetoroton excitations. Furthermore, we examine the advantages and limitations of DFT approaches, highlight the interplay between numerical simulations and theoretical models. We finally discuss the future potential of time-dependent DFT (TDDFT) for modeling non-equilibrium dynamics.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 11 figures
Unconventional magnetism in spin-orbit coupled systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-22 20:00 EDT
Jian-Keng Yuan, Zhiming Pan, Congjun Wu
Unconventional magnetism" was proposed to describe the exotic states arising from Landau-Pomeranchuk instabilities in the spin channel nearly two decades ago. Its odd-partial-wave-channel (e.g. $ p$ -wave) states break parity giving rise to the dynamic generation of spin-orbit coupling, while its even-partial-wave-channel (e.g. $ d$ -wave) states break time-reversal symmetry. Both types of states can exhibit collinear and non-collinear spin configurations over Fermi surfaces with the former and latter termed as the $ \alpha$ and $ \beta$ -phases, respectively. The collinear states in even partial-wave channels are in the same symmetry class of altermagnetism”. In this work, we investigate unconventional magnetism in both $ p$ - and $ d$ -wave channels within spin-orbit coupled systems with parity and time-reversal symmetries maintained. Based on the Ginzburg-Landau free energy analysis, the $ p$ -wave channel yields the gyrotropic, Rashba, Dresselhaus-type spin-orbit couplings. They compete and mix evolving from the $ \beta$ -phase to the $ \alpha$ -phase with various types of spin-momentum lockings. Analyses are performed in parallel for the $ d$ -wave unconventional magnetism. We emphasize that the single-particle dispersion is not sufficient to justify the spin-group type symmetry of the full Hamiltonian. Furthermore, Goldstone manifolds and excitations are examined in each unconventional magnetic phase.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages, 10 figures
Non-Equilibrium Probing of Topological Supersolids in Spin-Orbit-Coupled Dipolar Condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-22 20:00 EDT
Biao Dong, Xiao-Fei Zhang, Wei Han, Renyuan Liao, Xue-Ying Yang, Wu-Ming Liu, Yong-Chang Zhang
A chiral supersolid is a quantum phase that simultaneously exhibits crystalline order, superfluidity, and topological spin texture, with spontaneously broken translational, U(1) gauge, and chiral symmetries. Here, we demonstrate a chiral supersolid with tunable non-equilibrium dynamics in a spin-orbit coupled dipolar Bose-Einstein condensate. By adjusting dipolar interaction and spin-orbit coupling, we uncover two distinct quantum phase transitions: (i) a first-order transition from a single skyrmion superfluid to a triangular meron supersolid, and (ii) a second-order transition from this superfluid to a square skyrmion supersolid. These phases are characterized by their lattice symmetries, nonclassical rotational inertia, and spin textures. Under parity-time symmetric dissipation, we predict phase-dependent damping of the current oscillations, directly linked to the superfluid fraction. The predicted chiral supersolid phase can be experimentally observed in ultracold magnetic atoms with spin-orbit coupling. Our results establish dipolar quantum gases as a platform for designing topological matter with spintronic functionality.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Manipulation of anisotropic Zhang-Rice exciton in van der Waals antiferromagnets NiPS3-xSex by anion substitution
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Deepu Kumar, Joydev Khatua, Nguyen The Hoang, Yumin Sim, Rajesh Kumar Ulaganathan, Raju Kalaivanan, Raman Sankar, Maeng-Je Seong, Kwang-Yong Choi
Spin-entangled excitons have emerged as intriguing quasi-particle excitations in van der Waals magnets. Among them, the recently observed Zhang-Rice (ZR) exciton in NiPS3 has garnered significant research interest due to its strong correlation with magnetic ordering and its exceptionally long-lived coherence. Herein, we present our in-depth temperature- and polarization-dependent photoluminescence (PL) study of anion-substituted NiPS3-xSex (x=0.008,0.03,0.06 and 0.09 ) to explore the nature and dynamics of the ZR exciton. Our results reveal that, similar to the cation substitution, a small percentage of anion substitution effectively destroys and modulates the ZR exciton, as evidenced by the emergence of a weaker, lower-energy PL peak in addition to the primary ZR peak. The primary and secondary PL peaks exhibit the same anisotropic polarization but differ in their peak energy shift and intensity evolution with Se substitution, suggesting varying charge transfers of p-orbitals. Notably, the ZR exciton undergoes rapid thermal destabilization at much lower temperatures than two-magnon excitations, highlighting that p-orbital inhomogeneity beyond the magnetic ordering structure is a decisive factor in driving its thermal quenching.
Materials Science (cond-mat.mtrl-sci)
Persistent Homology-Based Descriptor of Topological Ordering in Two-Dimensional Quasi-Particle Systems with Application to Skyrmion Lattices
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
Michiki Taniwaki, Thomas Brian Winkler, Jan Rothörl, Raphael Gruber, Chiharu Mitsumata, Masato Kotsugi, Mathias Kläui
Two-dimensional (2D) quasi-particles systems, such as magnetic
skyrmions, can exhibit a rich variety of topological phase transitions.
However, the methodology for capturing the configurational properties of
the lattice ordering and constructing an appropriate descriptor that can
be easily calculated is not obvious. Here, we present a topological
descriptor, “persistent diagram”, and propose an indicator for
topological phase transitions using persistent homology (PH). PH offers
novel insights beyond conventional indicators by capturing topological
features derived from the configurational properties of the lattice. The
proposed persistent-homology-based topological indicator, which
selectively counts stable features in the persistence diagram,
effectively traces the lattice’s topological changes, as confirmed by
comparisons with the conventionally used measure of the ordering
$ \langle|\Psi_6|\rangle$ , typically used
to identify lattice phases. While our method is demonstrated in the
context of skyrmion lattice systems, the approach is general and can be
extended to other two-dimensional systems composed of repulsively
interacting quasi-particles. Moreover, our indicator offers lower
computational complexity than the conventionally used methods.
Statistical Mechanics (cond-mat.stat-mech)
18 pages, 6 figures, 1 table, 1 supplemental table, and 3 supplemental figures
Electromagnetic analysis of coated conductors with ferromagnetic substrates: Novel insights
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-22 20:00 EDT
Vladimir Sokolovsky, Leonid Prigozhin
Ferromagnetic substrates can significantly influence the electromagnetic response of a coated conductor to an external magnetic field and transport current. This study analyzes this response theoretically using the thin shell integrodifferential model. First, assuming the substrate is strongly magnetic and the superconductor is in the Meissner state, we present the analytical solution in a convenient explicit form. This helps us to analyze the superconducting current density distributions, highlighting their differences from those in conductors with non-magnetic substrates. Secondly, for a superconducting layer characterized by a nonlinear current-voltage relation and a substrate with a finite field-independent magnetic permeability, we use an effective spectral numerical method to study the unique features of this hybrid superconductor/ferromagnet system, such as magnetization in a parallel external field and the peculiar nonmonotonic variation of loss observed when alternating transport current and parallel field are applied simultaneously. Dynamic losses for the case of a direct transport current and an alternating parallel field are also investigated. It is shown that tuning the phase and amplitude of the applied parallel field relative to those of the transport current can minimize AC losses.
Superconductivity (cond-mat.supr-con)
16 pages, 8 figures
Long-lived Zone-boundary Magnons in an Antiferromagnet
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Jeongheon Choe, David Lujan, Gaihua Ye, Cynthia Nnokwe, Bowen Ma, Jiaming He, Frank Y. Gao, T. Nathan Nunley, Aritz Leonardo, Mikel Arruabarrena, Andres Ayuela, Jianshi Zhou, Martin Rodriguez-Vega, Gregory A. Fiete, Rui He, Xiaoqin Li
Antiferromagnetic (AFM) insulators exhibit many desirable features for spintronic applications such as fast dynamics in the THz range and robustness to fluctuating external fields. However, large damping typically associated with THz magnons presents a serious challenge for THz magnonic applications. Here, we report long-lived short-wavelength zone boundary magnons in the honeycomb AFM insulator CoTiO3, recently found to host topological magnons. We find that its zone-boundary THz magnons exhibit longer lifetimes than its zone-center magnons. This unusual momentum-dependent long magnon lifetime originates from several factors including the antiferromagnetic order, exchange anisotropy, a finite magnon gap, and magnon band dispersion. Our work suggests that magnon-magnon interaction may not be detrimental to magnon lifetimes and should be included in future searches for topological magnons.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
31 pages, 4 figures
Bulk nanocrystalline Al-Mg-Y alloys with amorphous grain boundary complexions display high strength and compressive plasticity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Tianjiao Lei, Esther Hessong, Brandon Fields, Raphael Pierre Thiraux, Daniel S. Gianola, Timothy J. Rupert
Although nanocrystalline alloys regularly exhibit high strengths, their use in structural applications often face challenges due to sample size limitations, unstable microstructures, and the limited ability to plastically deform. The incorporation of amorphous grain boundary complexions has been proposed to address these issues, by simultaneously stabilizing nanocrystalline grain structures for scale-up processing and improving alloy toughness. In the present study, the mechanical behavior of bulk nanocrystalline Al-Mg-Y is examined with macroscale compression testing, probing a length scale that is relevant to real-world structural applications. Bulk samples were fabricated via a simple powder metallurgy approach, with different pressing temperatures and times employed for consolidation in order to investigate microstructural and property evolution. All of the specimens contained primary face-centered cubic Al and secondary Al4C3 and Al3Y phases, with the Al3Y particles exhibiting two populations of small equiaxed and larger elongated particles. Appreciable plasticity was measured along with high ultimate stresses over 800 MPa due to the presence of amorphous grain boundary complexions. Microstructural characterization of fracture surfaces revealed that the area fraction of dimpled regions increased with longer hot-pressing time. Most importantly, the elongated Al3Y particles formed regular cellular patterns with increasing hot-pressing time, delaying shear localization and significantly enhancing plasticity. The hierarchy present in the microstructure of the Al-Mg-Y alloy, from amorphous grain boundary complexions to secondary phases, gives rise to excellent bulk mechanical properties, which are attractive for structural applications.
Materials Science (cond-mat.mtrl-sci)
Unveiling Fine Structure and Energy-driven Transition of Photoelectron Kikuchi Diffraction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Trung-Phuc Vo, Olena Tkach, Aki Pulkkinen, Didier Sebilleau, Aimo Winkelmann, Olena Fedchenko, Yaryna Lytvynenko, Dmitry Vasilyev, Hans-Joachim Elmers, Gerd Schonhense, Jan Minar
The intricate fine structure of Kikuchi diffraction plays a vital role in probing phase transformations and strain distributions in functional materials, particularly in electron microscopy. Beyond these applications, it also proves essential in photoemission spectroscopy (PES) at high photon energies, aiding in the disentanglement of complex angle-resolved PES data and enabling emitter-site-specific studies. However, the detection and analysis of these rich faint structures in photoelectron diffraction (PED), especially in the hard X-ray regime, remain highly challenging, with only a limited number of simulations successfully reproducing these patterns. The strong energy dependence of Kikuchi patterns further complicates their interpretation, necessitating advanced theoretical approaches. To enhance structural analysis, we present a comprehensive theoretical study of fine diffraction patterns and their evolution with energy by simulating core-level emissions from Ge(100) and Si(100). Using multiple-scattering theory and the fully relativistic one-step photoemission model, we simulate faint pattern networks for various core levels across different kinetic energies (106 eV - 4174 eV), avoiding cluster size convergence issues inherent in cluster-based methods. Broadening in patterns is discussed via the inelastic scattering treatment. For the first time, circular dichroism has been observed and successfully reproduced in the angular distribution of Si (100) 1s, revealing detailed features and asymmetries up to 31%. Notably, we successfully replicate experimental bulk and more “surface-sensitivity” diffraction features, further validating the robustness of our simulations. The results show remarkable agreement with the experimental data obtained using circularly polarized radiations, demonstrating the potential of this methodology for advancing high-energy PES investigations.
Materials Science (cond-mat.mtrl-sci)
Partial-Wetting Phenomena in Active Matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-22 20:00 EDT
Jing Zhang, Zhixin Liu, Shengda Zhao, Yangjun Yan, Rongxin Yue, Jiaxin Yu, Xinjie Li, Xinghua Zhang
Abundant interfacial phenomena in nature, such as water droplets on lotus leaves and water transport in plant vessels, originate from partial-wetting phenomena, which can be well described by Young’s equation. It remains an intriguing question whether similar behaviors exist in active matter. In this letter, we present a clear demonstration of the partial-wetting phenomenon in a ternary laning system, which is a typical active system. A phase diagram is constructed in which the relative drift velocities of different components govern the transitions among drying, partial wetting, and complete wetting states. The mechanical balance on the contact lines of the partial-wetting phase described by Young’s equation is verified. A theoretical picture is proposed to explain the analogy of partial wetting in the laning system to that in the equilibrium system.
Soft Condensed Matter (cond-mat.soft)
Main text: 6 pages, 3 figures. Supplementary Material included: 16 pages, 6 figures
Band-spin-valley coupled exciton physics in antiferromagnetic MnPS$_3$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Dan Wang, Haowei Chen, Yu Pang, Xiaolong Zou, Wenhui Duan
The introduction of intrinsic magnetic order in two-dimensional (2D) semiconductors offers great opportunities for investigating correlated excitonic phenomena. Here, we employ full-spinor GW plus Bethe-Salpeter equation methodology to reveal rich exciton physics in a prototypical 2D Néel-type antiferromagnetic semiconductor MnPS$ _3$ , enabled by the interplay among inverted dispersion of the second valence band, spin-valley coupling and magnetic order. The negative hole mass increases the reduced mass of the lowest-energy bright exciton, leading to exchange splitting enhancement of the bright exciton relative to band-edge dark exciton. Notably, such splitting couples with spontaneous valley polarization to generate distinct excitonic fine structure between $ K$ and $ -K$ valleys, which dictate distinct relaxation behaviors. Crucially, magnetic order transition from Néel antiferromagnetic to ferromagnetic state induces significant quasiparticle band structure reconstruction and excitonic transitions modification, with low-energy optical excitations being exclusively contributed by majority-spin channel. These findings establish 2D antiferromagnetic semiconductors as an intriguing platform to study band-spin-valley coupled exciton physics.
Materials Science (cond-mat.mtrl-sci)
Converting $PT$-Symmetric Topological Classes by Floquet Engineering
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Going beyond the conventional classification rule of Altland-Zirnbauer symmetry classes, $ PT$ symmetric topological phases are classified by $ (PT)^2=1$ or $ -1$ . The interconversion between the two $ PT$ -symmetric topological classes is generally difficult due to the constraint of $ (PT)^2$ . Here, we propose a scheme to control and interconvert the $ PT$ -symmetric topological classes by Floquet engineering. We find that it is the breakdown of the $ \mathbb{Z}_2$ gauge, induced by the $ \pi$ phase difference between different hopping rates, by the periodic driving that leads to such an interconversion. Relaxing the system from the constraint of $ (PT)^2$ , rich exotic topological phases, e.g., the coexisting $ PT$ -symmetric first-order real Chern insulator and second-order topological insulators not only in different quasienergy gaps, but also in one single gap, are generated. In contrast to conventional Floquet topological phases, our result provides a way to realize exotic topological phases without changing symmetries. It enriches the family of topological phases and gives an insightful guidance for the development of multifunctional quantum devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
7 pages and 4 figures
Language Models for Materials Discovery and Sustainability: Progress, Challenges, and Opportunities
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Zongrui Pei, Junqi Yin, Jiaxin Zhang
Significant advancements have been made in one of the most critical branches of artificial intelligence: natural language processing (NLP). These advancements are exemplified by the remarkable success of OpenAI’s GPT-3.5/4 and the recent release of GPT-4.5, which have sparked a global surge of interest akin to an NLP gold rush. In this article, we offer our perspective on the development and application of NLP and large language models (LLMs) in materials science. We begin by presenting an overview of recent advancements in NLP within the broader scientific landscape, with a particular focus on their relevance to materials science. Next, we examine how NLP can facilitate the understanding and design of novel materials and its potential integration with other methodologies. To highlight key challenges and opportunities, we delve into three specific topics: (i) the limitations of LLMs and their implications for materials science applications, (ii) the creation of a fully automated materials discovery pipeline, and (iii) the potential of GPT-like tools to synthesize existing knowledge and aid in the design of sustainable materials.
Materials Science (cond-mat.mtrl-sci)
89 pages, 21 figures
Highly Stable Silicon Anodes Enabled by Sub-10 nm Pores and Particles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Pankaj Ghildiyal, Brandon Wagner, Jianjun Chen, Tu Nguyen, Aishwarya Belamkar, Juchen Guo, Lorenzo Mangolini
Silicon anodes offer high energy densities for next-generation lithium-ion batteries; however, their application is limited by severe volume expansion during cycling. Making silicon porous or nanostructured mitigates this expansion but often increases lithium inventory losses due to the inherent high surface area of nanomaterials. This study introduces a simple bottom-up process that overcomes this limitation. The approach relies on small silicon particles (<10 nm) produced using an efficient low-temperature plasma approach. These small building blocks are assembled into micron-scale superstructures characterized by uniformly dispersed sub-10 nm pores. This structure addresses both volume expansion and lithium-inventory issues while achieving tap densities exceeding those of commercial graphite (~1.2 g/cm3), all while maintaining good processability. The resulting silicon-dominant anodes achieve remarkable stability in full pouch cells with NMC811 and LFP cathodes, retaining ~80% capacity for more than 400 cycles without pre-lithiation, graphite blending, or pre-cycling.
Materials Science (cond-mat.mtrl-sci)
Free Energy Distribution and Relaxation Dynamics Near the First-Order Transition Line
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
Ranran Guo, Xiaobing Li, Mingmei Xu, Jinghua Fu, Yuanfang Wu
Using the three-dimensional kinetic Ising model with Metropolis algorithm, we calculate the free energy in the whole phase boundary, particularly near the first phase transition line (1st-PTL).The results show that along the 1st-PTL, as the temperature decreases, the energy barrier between the two coexisting phases diverges. This results in more difficulty to reach the equilibrium, i.e., ultra-slow relaxation, which has been recently demonstrated. Meanwhile, we exam the randomness of the equilibrium time. It is found that near the 1st-PTL the equilibrium time is self-diverging, in contrast to the non-self-averaging near the critical point.
Statistical Mechanics (cond-mat.stat-mech)
7 pages, 4 figures
Vector pulse magnet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Kosuke Noda, Kent Seki, Dilip Bhoi, Kazuyuki Matsubayashi, Kazuto Akiba, Akihiko Ikeda
The underlying symmetry of the crystal, electronic structure, and magnetic structure manifests itself in the anisotropy of materials’ properties, which is a central topic of the present condensed matter research. However, it demands such a considerable effort to fill the explorable space that only a small part has been conquered. We report a vector pulse magnet (VPM) as an alternative experimental technique to control the direction of applied magnetic fields, which may complement the conventional methods with its characteristic features. The VPM combines a conventional pulse magnet and a vector magnet. The VPM can create vector pulsed magnetic fields and swiftly rotating pulsed magnetic fields. As a demonstration, the three-dimensional magnetoresistance measurement of a highly oriented pyrolytic graphite is carried out using the AC four-probe method at 4.5 K and 6 T. The two-dimensional electronic structure of graphite is visualized in the three-dimensional magnetoresistance data. One can uncover the rotational and time-reversal symmetry of materials using a VPM and a variety of measurement techniques.
Materials Science (cond-mat.mtrl-sci)
4 pages, 5 figures
Erratic non-Hermitian skin localization
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-22 20:00 EDT
A novel localization phenomenon, termed erratic non-Hermitian skin localization, has been identified in disordered globally-reciprocal non-Hermitian lattices. Unlike conventional non-Hermitian skin effect and Anderson localization, it features macroscopic eigenstate localization at irregular, disorder-dependent positions with sub-exponential decay. Using the Hatano-Nelson model with disordered imaginary gauge fields as a case study, this effect is linked to stochastic interfaces governed by the universal order statistics of random walks. Finite-size scaling analysis confirms the localized nature of the eigenstates. This discovery challenges conventional wave localization paradigms, offering new avenues for understanding and controlling localization phenomena in non-Hermitian physics.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Optics (physics.optics), Quantum Physics (quant-ph)
7 pages, 5 figures, accepted for publication in the Physical Review Letters
Metamorphic quantum dot arrays in twisted trilayer hexagonal boron nitride
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Kunihiro Yananose, Changwon Park, Young-Woo Son
A large set of controlled quantum states with tunable spacing and interactions is crucial in understanding and engineering novel quantum materials for quantum information processing. Such achievements have been mostly confined to atomic physics, exemplified by ordered arrays of neutral atoms or trapped ions. In solid-state systems, well-ordered quantum dots (QDs), in particular, also have significant potential for these applications. However, their precise large-scale fabrication and on-demand reconfigurations remain important challenges. Here, we predict that twisted trilayer hexagonal boron nitride hosts well-defined QD arrays with spatial precision and symmetry control as well as exceptional dynamic repositioning. These arrays emerge naturally at ultrasmall twist angles, forming diverse domain configurations including triangular, kagome and hexagram arrangements. The quantum states within each dot exhibit high fidelity to quantum harmonic oscillator wavefunctions, realizing uniform dot states as long as the moire-of-moire lattice is well ordered. Uniquely, we demonstrate that these arrays can be dynamically reconfigured via external electric fields coupled to local electric polarizations, allowing continuous tuning between regimes of strong coupling and complete isolation, and offering a pathway to long-ranged quantum information shuttling. This tunability and uniformity distinguish our platform from conventional implementations and suggest substantial potential for quantum applications, from array-based single-photon sources to scalable quantum processors, establishing twisted van der Waals systems as a promising platform for programmable quantum architectures with spatial and energetic control.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
14 pages, 4 figures, additional extended materials
Photoinduced DC Hall current in few-layer black phosphorus with a gate-tunable Floquet gap
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Taehun Kim, Hansol Kim, Dongeun Kim, Hongki Min
We theoretically explore Floquet engineering in few-layer black phosphorus (fBP) under time-periodic driving. Motivated by the ability of circularly polarized light to induce nontrivial topological states at Dirac nodes, we investigate the emergence of a photoinduced DC Hall effect in the Dirac semimetal phase of fBP. Starting from a low-energy continuum model, we derive the effective Floquet Hamiltonian and analytically calculate the Berry curvature, demonstrating the opening of a topological gap. We also perform lattice-model calculations incorporating a self-consistent Hartree method to compute Floquet band structures and DC Hall conductivity under a perpendicular electric field. Our results reveal that the DC Hall current in fBP can be effectively tuned via a periodic driving field and electrostatic gating.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
10 pages, 7 figures
Transition temperature of a two-component Bose-Einstein condensates in improved Hartree-Fock approximation
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-22 20:00 EDT
In this study, we investigate the transition temperature of a two-component Bose-Einstein condensates by means of Cornwall-Jackiw-Tomboulis effective action formalism within the framework of the improved Hartree-Fock approximation. Influence of intra- and interspecies interactions as well as of the thermal fluctuations to the transition temperature are considered up to leading order of the gas parameters and scattering lengths.
Quantum Gases (cond-mat.quant-gas)
Gapless behavior in a two-leg spin ladder with bond randomness
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-22 20:00 EDT
Yu Tominaga, Itsuki Shimamura, Takanori Kida, Masayuki Hagiwara, Koji Araki, Yuko Hosokoshi, Yoshiki Iwasaki, Hironori Yamaguchi
We successfully synthesized [Cu$ _2$ (AcO)$ _4$ ($ p$ -Py-V-$ p$ -F)$ _2$ ]$ \cdot$ 4CHCl$ _3$ , a verdazyl-based complex with a paddlewheel structure comprising two Cu atoms, which induces strong antiferromagnetic (AF) exchange interactions between Cu spins, generating a nonmagnetic singlet state at low temperatures. Two primary exchange interactions between radical spins generate a spin-1/2 AF two-leg ladder. In addition, two possible positional configurations of the F atom in the complex create four different overlap patterns of molecular orbitals, introducing bond randomness in the spin ladder. The observed experimental behaviors, such as the Curie tail in the magnetic susceptibility and the gapless gradual increase in the magnetization curve, are attributed to a broad distribution of excitation energies and a few orphan spins in the random-singlet (RS) state that are stabilized by bond randomness. The low-temperature specific heat exhibits a temperature dependence with $ \propto 1/|{\rm{ln}}T|^3$ , demonstrating the formation of the RS state in unfrustrated systems. We also consider the effect of restricted patterns of exchange interactions and one-dimensional nature of the system on the RS state.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
8 pages, 5 figures
Phys. Rev. B 111, 134430 (2025)
Effect of presence of rigid impurities in a system of annihilating domain walls with dynamic bias
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
The dynamics of interacting domain walls, regarded as a system of particles which are biased to move towards their nearest neighbours and annihilate when they meet, have been studied in the recent past. We study the effect of the presence of a fraction $ r$ of quenched impurities (which act as rigid walkers) on the dynamics. Here, in case two domain walls or one impurity and one domain wall happen to be on the same site, both get simultaneously annihilated. It is found that for any non-zero value of $ r$ , the dynamical behaviour changes as the surviving fraction of particles $ \rho(t)$ attains a constant value. $ \rho(t)t^\alpha $ shows a universal behaviour when plotted against $ r^\beta t$ with $ \alpha, \beta$ values depending on whether the particles are rigid or nonrigid. Also, the values differ for the biased and unbiased cases. The time scale associated with the particle decay obtained in several ways shows that it varies with $ r$ in a power law manner with a universal exponent.
Statistical Mechanics (cond-mat.stat-mech)
8 Pages, 13 figures
Layered semiconductors integrated with polyimide thin films for high-quality valleytronic and quantum-photonic systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Jithin T Surendran, Indrajeet D Prasad, Kenji Watanabe, Takashi Taniguchi, Santosh Kumar
Dielectric integration of layered semiconductors is a prerequisite for fabricating high-quality optoelectronic, valleytronic, and quantum-photonic devices. While hexagonal boron nitride (hBN) is the current benchmark dielectric, exploration of the most suitable dielectric materials covering the complete substrates continues to expand. This work demonstrates the formation of high optical-quality excitons in two widely explored layered semiconductors, WSe$ _2$ and WS$ _2$ , integrated into polyimide (PI) thin films of thicknesses $ \approx$ 500 nm. The photoluminescence (PL) studies at $ T$ = 296 K show the formation of neutral excitons $ \left(X^0\right)$ and trions in fully-PI-encapsulated 1L-WSe$ _2$ with 2-sigma ($ 2\sigma$ ) spatial-inhomogeneity of 4.5 (3.4) meV in $ X^0$ emission energy (linewidth), which is $ \approx$ 1/3rd (1/5th), respectively, that of inhomogeneity measured in fully-hBN-encapsulated 1L-WSe$ _2$ . A smaller $ 2\sigma$ of 2.1 (2.3) meV in $ X^0$ emission energy (linewidth) has been shown for fully-PI-encapsulated 1L-WS$ _2$ . Polarization-resolved and excitation power-dependent PL measurements of PI-isolated 1L-TMDs at $ T$ = 4 K further reveal formations of high-quality neutral-biexcitons and negatively-charged biexcitons, with degrees of valley-polarization up to 21$ %$ under non-resonant excitation. Furthermore, the fully-PI-encapsulated 1L-WSe$ _2$ also hosts single quantum emitters with narrow linewidths and high-spectral stability. This work indicates that PI thin films may serve the purpose of high-quality dielectric material for integrating the layered materials on a wafer scale.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Optics (physics.optics), Quantum Physics (quant-ph)
5 Figures and 3 Supplementary Figures
The compliance of the molecular hydride superconductor $BiH_4$ with the Migdal’s theorem
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-22 20:00 EDT
E.F. Talantsev, Yu.V. Blinova, A.V. Korolev
The discovery of near-room-temperature superconductivity in H3S sparked experimental and theoretical studies of highly compressed hydrides with the aim of obtaining room-temperature superconductivity. There are two dominant hydride classes where the search is ongoing: the first class is the covalently bonded hydrides (which is represented by H3S), and the second class is the clathrate-type hydrides (which is represented by LaH10, YH6, CaH6). Recently, the third class of superconducting hydrides, where the hydrogen remains its molecular form, has been discovered. This class is represented by BaH12 and BiH4. Here, we analyzed experimental data for the BaH12 and BiH4. We found that the BaH12 exhibits grains of an average size of 26 nm and a low level of microstrain 0.1%, in the range of 126 GPa < P < 160 GPa. We also derived the Debye $ \Theta_D$ and Einstein $ \Theta_E$ temperatures, and the electron-phonon coupling constant $ \Lambda_{e-ph} $ in BaH12 and BiH4. The $ \Lambda_{e-ph} $ in BiH4 significantly differs from the values obtained by first-principles calculations. The derived Fermi temperature $ T_F = 20,000 K$ for BiH4 positions this molecular hydride between the unconventional and conventional superconductors bands in the Uemura plot. This position is outside of the band where covalently bonded and clathrate hydrides are located. The ratio $ \Theta_D / T_F = 0.026 $ of BiH4 is typical for pure metals and A-15 alloys. This implies that the BiH4, is the first hydride superconductor which complains with the Migdal’s theorem.
Superconductivity (cond-mat.supr-con)
21 pages, 8 figures
Fickian Yet non-Gaussian Diffusion in Complex Molecular Fluids via a non-local diffusion framework
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-22 20:00 EDT
H. Srinivasan, V. K. Sharma, S. Mitra
Fickian yet non-Gaussian diffusion (FnGD) has gained popularity in the recent times owing to it’s ubiquity in a variety of complex fluids. However, whether FnGD can be observed experimentally in molecular fuids is still obscure with very little study in real systems. In this letter, we show existence of FnGD in molecular fluids based on compelling evidence from incoherent quasielastic neutron scattering (IQENS). Using a cage-jump diffsion model, we show that while the approach to Fickianity is exponentially fast, the Gaussianity is restored at a much slower algebraic rate. We propose a non-local diffusion (NLD) model to describe a d-dimensional jump-diffusion in FnGD regime and show their universal applicability in such systems. This study establishes that cage-jump diffusion process inevitably lead to FnGD and provides the framework of NLD models to explore such diffusion phenomena in any arbitrary dimensions.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
Extending Collinear Density Functionals to Noncollinear Cases under Periodic Boundary Condition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Accurate modeling of spin-orbit coupling and noncollinear magnetism in materials requires noncollinear density functionals within the two-component generalized Kohn-Sham (GKS) framework, yet constructing and implementing noncollinear functionals remains challenging. Recently, a methodology was proposed to extend collinear functionals into noncollinear ones, successfully defining noncollinear functionals and their derivatives. However, the initial implementation involved a systematic approach to differentiate energy over density matrix elements rather than the derivatives of the energy functional with respect to density, presenting challenges for integration with periodic boundary condition-density functional theory (PBC-DFT) software. We have derived a novel set of working equations based on the original methodology, which provides noncollinear energy functionals and their derivatives. These working equations have been implemented in our noncollinear functional ensemble named NCXC, ensuring numerical stability and transferability without the need for incorporating derivatives of basis functions. This implementation is expected to facilitate compatibility with most DFT software packages. We demonstrate some preliminary applications in periodic systems, including noncollinear magnetism in spin spirals, band structures in topological insulators, and band gaps in semiconducting inorganic materials, using NCXC.
Materials Science (cond-mat.mtrl-sci)
34 pages, 5 figures, 2 tables
Predicting Methane Adsorption in Metal-Substituted MOFs: A Comparative Study between Density Functional Theory and Machine Learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Metal-organic frameworks (MOFs) are promising materials for methane capture due to their high surface area and tunable properties. Metal substitution represents a powerful strategy to enhance MOF performance, yet systematic exploration of the vast chemical space remains challenging. In this work, we compare density functional theory (DFT) and machine learning (ML) in predicting methane adsorption properties in metal-substituted variants of three high-performing MOFs: M-HKUST-1, M-ATC, and M-ZIF-8 (M = Cu, Zn). DFT calculations reveal significant differences in methane binding energetics between Cu and Zn variants of all three MOFs. On the other hand, we fine-tuned a pretrained multimodal ML model, PMTransformer, on a curated subset of hypothetical MOF (hMOF) structures to predict macroscopic adsorption properties. While the model qualitatively predicts adsorption properties for the original unaltered MOFs, it fails to distinguish between metal variants despite their different binding energetics identified by DFT. We trace this limitation to the hMOF training data generated using Grand Canonical Monte Carlo (GCMC) simulations based on classical force fields (UFF/TraPPE). Our study highlights a key challenge in ML-based MOF screening: ML models inherit the limitations of their training data, particularly when electronic effects significantly impact adsorption behavior. Our findings emphasize the need for improved force fields or hybrid GCMC/DFT datasets to incorporate both geometric and electronic factors for accurate prediction of adsorption properties in metal-substituted MOFs.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
11 pages, 6 figures
Ordering and association of patchy particles in narrow channels
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
We show that the formalism of Wertheim’s first order thermodynamic perturbation theory can be generalised for the fluid of anisotropic sticky particles confined to a quasi-one-dimensional channel. Using the transfer matrix method, we prove that the theory is exact if the hard body interaction is additive, only the first neighbors interact and the particles can stick together only along the channel. We show that the most convenient treatment of association in narrow channels is to work in NPT ensemble, where all structural and thermodynamic quantities can be expressed as a function of pressure and fraction of sites unbonded.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
12 pages, 3 figures
Learning via mechanosensitivity and activity in cytoskeletal networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-22 20:00 EDT
Deb S. Banerjee, Martin J. Falk, Margaret L Gardel, Aleksandra M. Walczak, Thierry Mora, Suriyanarayanan Vaikuntanathan
In this work we show how a network inspired by a coarse-grained description of actomyosin cytoskeleton can learn - in a contrastive learning framework - from environmental perturbations if it is endowed with mechanosensitive proteins and motors. Our work is a proof of principle for how force-sensitive proteins and molecular motors can form the basis of a general strategy to learn in biological systems. Our work identifies a minimal biologically plausible learning mechanism and also explores its implications for commonly occuring phenomenolgy such as adaptation and homeostatis.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
10 pages, 9 figurs
Electronic stopping cross sections of tungsten to swift ions and comparisons with models
New Submission | Other Condensed Matter (cond-mat.other) | 2025-04-22 20:00 EDT
Tiago F. Silva, Arilson Silva, Cleber L. Rodrigues, Nemitala Added, Manfredo H. Tabacniks, Flávio Matias, Helio Yoriyaz, Julian Shorto
Accurate stopping power data for tungsten is crucial for ion beam analysis (IBA) techniques applied to fusion-related materials. In this work, we present new experimental measurements of the stopping power of tungsten for protons and alpha particles, addressing key gaps in fundamental databases. Our results provide a densely spaced dataset, refining the practical uncertainty limits to approximately 1.5% for protons and 4% for alpha particles. We critically compare our findings with semi-empirical and theoretical models, evaluating their performance in describing the stopping power of tungsten for light projectiles. By improving the accuracy and reliability of stopping power data, we contribute to the enhancement of the applicability of ion-beam methods for characterizing tungsten in fusion-related research. These findings contribute to the refinement of semi-empirical models and support the ongoing efforts to develop more precise theoretical frameworks for ion-solid interactions in high-Z materials.
Other Condensed Matter (cond-mat.other), Nuclear Experiment (nucl-ex)
22 pages, 3 figures
The phase diagram of CeRh${2}$As${2}$ for out-of-plane magnetic field
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-22 20:00 EDT
P.Khanenko (1), J. F. Landaeta (1), S. Ruet (1), T. Lühmann (1), K. Semeniuk (1, 2), M. Pelly (3), A. W. Rost (3), G. Chajewski (4), D. Kaczorowski (4), C. Geibel (1), S. Khim (1), E. Hassinger (2), M. Brando (1) ((1) Max Planck Institute for Chemical Physics of Solids, Dresden, Germany, (2) Technical University Dresden, Institute for Solid State and Materials Physics, Dresden, Germany, (3) Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St. Andrews, St. Andrews, United Kingdom, (4) Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Wrocław, Poland)
The heavy-fermion superconductor CeRh$ {2}$ As$ {2}$ ($ T{\textrm{c}} = 0.35, \textrm{K}$ ) shows two superconducting (SC) phases, SC1 and SC2, when a magnetic field is applied parallel to the $ c$ axis of the tetragonal unit cell. All experiments to date indicate that the change in SC order parameter detected at $ \mu{\textrm{0}}H^{\ast} \approx 4, \textrm{T}$ is due to strong Rashba spin-orbit coupling at the Ce sites caused by the locally non-centrosymmetric environments of the otherwise globally centrosymmetric crystalline structure. Another phase (phase I) exists in this material below $ T_{\textrm{0}} = 0.54, \textrm{K}$ . In a previous specific heat study [K. Semeniuk et al. Phys. Rev. B, $ 107$ , L220504 (2023)] we have shown that phase I persists up to a field $ \mu_{\textrm{0}}H_{0} \approx 6, \textrm{T}$ , larger than $ H^{\ast}$ . From thermodynamic arguments we expected the phase-I boundary line to cross phase SC2 at a tetracritical point. However, we could not find any signature of the phase-I line inside the SC2 phase and speculated that this was due to the fact that the $ T_{0}(H)$ line is almost perpendicular to the $ H$ axis and, therefore, invisible to $ T$ -dependent measurements. This would imply a weak competition between the two order parameters. Here, we report magnetic field dependent measurements of the magnetostriction and ac-susceptibility on high-quality single crystals. We see clear evidence of the singularity at $ H_{0}$ inside the SC2 phase and confirm our previous prediction. Furthermore, we observe the transition across the $ T^{\ast}(H)$ line in $ T$ -dependent specific heat measurements, which show that the $ T^{\ast}(H)$ line is not perpendicular to the field axis, but has a positive slope. Our work supports recent $ \mu$ SR results which suggest coexistence of phase I with superconductivity.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
9 pages, 11 figures, includes supplemental material
Non-Hermitian Hopf insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-22 20:00 EDT
Daichi Nakamura, Kohei Kawabata
Hopf insulators represent a unique class of topological insulators that exist exclusively in two-band systems and are inherently unstable upon the inclusion of additional bands. Meanwhile, recent studies have shown that non-Hermiticity gives rise to distinctive complex-energy gap structures, known as point gaps, and associated topological phases with no analogs in Hermitian systems. However, non-Hermitian counterparts of Hopf insulators have remained largely elusive. Here, we generally classify topological phases of two-band non-Hermitian systems based on the homotopy theory and uncover Hopf-type point-gap topology present only for two bands. Specifically, we reveal such Hopf-type point-gap topology for three-dimensional systems with chiral symmetry (class AIII) and four-dimensional systems with no symmetry (class A). Explicitly constructing prototypical models from the Hermitian Hopf insulator, we further demonstrate that these non-Hermitian topological phases lead to anomalous point-gapless boundary states spectrally detachable from the bulk bands.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
13 pages, 6 figures, 2 tables
Interacting Copies of Random Constraint Satisfaction Problems
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-22 20:00 EDT
Maria Chiara Angelini, Louise Budzynski, Federico Ricci-Tersenghi
We study a system of $ y=2$ coupled copies of a well-known constraint satisfaction problem (random hypergraph bicoloring) to examine how the ferromagnetic coupling between the copies affects the properties of the solution space. We solve the replicated model by applying the cavity method to the supervariables taking $ 2^y$ values. Our results show that a coupling of strength $ \gamma$ between the copies decreases the clustering threshold $ \alpha_d(\gamma)$ , at which typical solutions shatters into disconnected components, therefore preventing numerical methods such as Monte Carlo Markov Chains from reaching equilibrium in polynomial time. This result needs to be reconciled with the observation that, in models with coupled copies, denser regions of the solution space should be more accessible. Additionally, we observe a change in the nature of the clustering phase transition, from discontinuous to continuous, in a wide $ \gamma$ range. We investigate how the coupling affects the behavior of the Belief Propagation (BP) algorithm on finite-size instances and find that BP convergence is significantly impacted by the continuous transition. These results highlight the importance of better understanding algorithmic performance at the clustering transition, and call for a further exploration into the optimal use of re-weighting strategies designed to enhance algorithmic performances.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
19 pages, 8 figures
Improving efficiency and stability for perovskite solar cell with diethylene glycol dimethacrylate modification
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Xiaodan Wei, Shuyuan Zhang, Boyang Ma, Zehua Feng, chunhan Yu, Linyuan Peng, Zijian Hua, Jie Xu
The humidity resistance is the key challenges that hinder the commercial application of perovskite solar cells (PSCs). Herein, we propose an ultra-thin acrylate polymer (diethylene glycol dimethacrylate, DGDMA) into perovskite films to investigate the influence of polymerized networks on stability. The monomer molecules containing acrylate and carbonyl groups were selected, and the effects of the polymerized were quantified with different concentration. The experimental results show that, when the concentration of DGDMA is 1 mg/ml, the PCE increases from 18.06% to 21.82%, which is optimum. The monomer molecules with carbonyl groups polymerize, they can chelate with uncoordinated Pb2+ in perovskite films to improve the film quality, reduce the surface defect density to decrease non-radiative recombination, and also significantly enhance the humidity stability of PSCs.
Materials Science (cond-mat.mtrl-sci)
Spin dynamics and 1/3 magnetization plateau in a coupled distorted diamond chain compound K2Cu3(MoO4)4
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-22 20:00 EDT
G. Senthil Murugan, J. Khatua, Suyoung Kim, Eundeok Mun, K. Ramesh Babu, Heung-Sik Kim, C.-L. Huang, R. Kalaivanan, U. Rajesh Kumar, I. Panneer Muthuselvam, W. T. Chen, Sritharan Krishnamoorthi, K.-Y. Choi, R. Sankar
We investigate magnetic properties of the $ s$ = 1/2 compound K$ {2}$ Cu$ {3}$ (MoO$ {4}$ )$ {4}$ by combining magnetic susceptibility, magnetization, specific heat, and electron spin resonance (ESR) with density functional calculations. Its monoclinic structure features alternating Cu$ ^{2+}$ ($ s$ = 1/2) monomers and edge-shared dimers linked by MoO$ {4}$ units, forming a distorted diamond chain along the $ a$ -axis. Antiferromagnetic order occurs at $ T{\rm N}$ = 2.3 K, as evident from a $ \lambda$ -type anomaly in specific heat and magnetic susceptibility derivatives. Inverse magnetic susceptibility reveals coexisting ferro- and antiferromagnetic interactions. Specific heat and ESR data show two characteristic temperatures: one at 20 K, associated with spin-singlet formation in Cu$ {2}$ O$ {9}$ dimers, and another at 3.68 K, indicating short-range correlations between dimers and monomers. Magnetization measurements reveal a metamagnetic transition at 2.6 T and a critical magnetic field $ \mu{0}H{c}$ = 3.4 T, where a 1/3 magnetization plateau emerges with saturation near 0.35 $ \mu{\rm B}$ . Low-temperature specific heat and magnetization data reveal the suppression of long-range order at $ \mu{0}H{c}$ , enabling the construction of a temperature-magnetic field phase diagram showing multiple magnetic phases near the $ \mu{0}H_{c}$ . Density functional theory confirms a distorted diamond chain with $ J_{1}$ dimers and competing $ J_2$ , $ J_4$ , $ J_3$ , and $ J_5$ interactions with monomer spins as an effective low-temperature spin model.
Strongly Correlated Electrons (cond-mat.str-el)
Phys.Rev.B111,144420(2025)
The preparation and properties of polycrystalline Bi$_2$O$_2$Se – pitfalls and difficulties with reproducibility and charge transport limiting parameters
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-22 20:00 EDT
Jan Zich, Tomáš Plecháček, Antonín Sojka, Petr Levinský, Jiří Navrátil, Pavlína Ruleová, Stanislav Šlang, Karel Knížek, Jiří Hejtmánek, Vojtěch Nečina, Čestmír Drašar
Thermoelectric materials allow the direct conversion of waste heat into electricity, and novel materials are being investigated for this purpose. Recently, doped Bi$ _2$ O$ _2$ Se has shown high application potential. In this study, we discuss causes for large variation in reported transport properties of pure Bi$ _2$ O$ _2$ Se and present a preparation method that improves the reproducibility of undoped polycrystalline samples and improves their stability under thermal cycling. Key steps of this method include calcination of the Bi$ _2$ O$ _3$ precursor, purification of the synthesized material in a temperature gradient, use of a coarse particle fraction and compaction of the powders in a Si3N4 die instead of a graphite die. The resulting polycrystalline material exhibits improved reproducibility and enhanced resistance to thermal cycling. It has room temperature electrical conductivity {\sigma}RT ~ 500 S.m-1 and Seebeck coefficient S ~ -300 $ \mu$ V.K$ ^{-1}$ . These properties make it suitable as a reference material for future doping studies. The presented synthesis approach may provide a more reliable platform for investigating the intrinsic behavior and doping response of Bi$ _2$ O$ _2$ Se in thermoelectric applications.
Materials Science (cond-mat.mtrl-sci)
Manuscript: 20 pages, 9 figures. Electronic Supplementary Material: 21 pages, 16 figures, 11 tables
Swap Monte Carlo for diatomic molecules
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-22 20:00 EDT
Till Böhmer, Jeppe C. Dyre, Lorenzo Costigliola
In recent years the Swap Monte Carlo algorithm has led to remarkable progress in equilibrating supercooled model liquids at low temperatures. Applications have so far been limited to systems composed of spherical particles, however, whereas most real-world supercooled liquids are molecular. We here introduce a simple size-polydisperse molecular model that allows for efficient thermal equilibration \textit{in silico} with the Swap Monte Carlo method, resulting in an estimated speedup of $ 10^3-10^6$ at moderate polydispersity (5-10 %). Despite being polydisperse, the model exhibits little difference between the size-resolved orientational time-autocorrelation functions. Our results demonstrate the possibility of designing molecular models that can be simulated close to the calorimetric glass transition.
Soft Condensed Matter (cond-mat.soft)
Tracer dynamics in an interacting active bath: fluctuations and energy partition
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-22 20:00 EDT
We investigate the dynamics of a massive tracer particle coupled to an interacting active bath, modeled as a harmonic chain of overdamped active particles analytically, with an aim to understand the impact of bath interactions and activity on the nonequilibrium fluctuations of the tracer. From the microscopic equations, we derive the tracer particle’s effective Langevin equation, obtaining the dissipative and stochastic forces from the bath. We analyze the friction kernel, revealing power-law tails in the weak coupling limit and exponential decay in the strong coupling regime. Due to the interplay between bath interactions, probe-bath coupling, and activity, the mean squared displacement, velocity, and stationary velocity correlations exhibit different dynamical regimes, which we characterize analytically. Under harmonic confinement, we find that energy equipartition holds at low activity but breaks down at higher activity, with the kinetic energy exhibiting a non-monotonic dependence on the activity of the bath.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
27 pages, 10 figures