CMP Journal 2025-04-21
Statistics
arXiv: 43
arXiv
Landau theory of CeCoSi
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
We investigate both the nonmagnetic and magnetic ordered phases of CeCoSi using Landau theory. Our analysis predicts that three successive phase transitions occur at zero magnetic field. In the intermediate phase, an out-of-plane magnetic moment may be present or absent. If present, magnetic fields applied along the [100] and [110] directions induce additional magnetic phases.
Strongly Correlated Electrons (cond-mat.str-el)
2 pages, 1 figure
Superzone gap formation induced by ferroic orders
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
We demonstrate that a superzone gap, typically associated with antiferroic ordering, can also emerge from ferroic orders in systems with sublattice degrees of freedom. By analyzing a $ p$ -orbital tight-binding model on a zigzag chain, we show that a Su–Schrieffer–Heeger-type gap is induced by ferroquadrupolar or ferromagnetic order or by applying an external magnetic field.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
2 pages, 2 figures
Response to recent comments on Phys. Rev. B 107, 245423 (2023) and Subsection S4.3 of the Supp. Info. for Nature 638, 651-655 (2025)
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
Morteza Aghaee, Zulfi Alam, Mariusz Andrzejczuk, Andrey E. Antipov, Mikhail Astafev, Amin Barzegar, Bela Bauer, Jonathan Becker, Umesh Kumar Bhaskar, Alex Bocharov, Srini Boddapati, David Bohn, Jouri Bommer, Leo Bourdet, Samuel Boutin, Benjamin J. Chapman, Sohail Chatoor, Anna Wulff Christensen, Patrick Codd, William S. Cole, Paul Cooper, Fabiano Corsetti, Ajuan Cui, Andreas Ekefjärd, Saeed Fallahi, Luca Galletti, Geoff Gardner, Deshan Govender, Flavio Griggio, Ruben Grigoryan, Sebastian Grijalva, Sergei Gronin, Jan Gukelberger, Marzie Hamdast, Esben Bork Hansen, Sebastian Heedt, Samantha Ho, Laurens Holgaard, Kevin Van Hoogdalem, Jinnapat Indrapiromkul, Henrik Ingerslev, Lovro Ivancevic, Thomas Jensen, Jaspreet Jhoja, Jeffrey Jones, Konstantin V. Kalashnikov, Ray Kallaher, Rachpon Kalra, Farhad Karimi, Torsten Karzig, Maren Elisabeth Kloster, Christina Knapp, Jonne Koski, Pasi Kostamo, Tom Laeven, Gijs de Lange, Thorvald Larsen, Jason Lee, Kyunghoon Lee, Grant Leum, Kongyi Li, Tyler Lindemann, Matthew Looij, Marijn Lucas, Roman Lutchyn, Morten Hannibal Madsen, Nash Madulid, Michael Manfra, Signe Brynold Markussen, Esteban Martinez, Marco Mattila, Robert McNeil, Ryan V. Mishmash, Gopakumar Mohandas, Christian Mollgaard, Michiel de Moor, Trevor Morgan, George Moussa, Chetan Nayak, William Hvidtfelt Padkær Nielsen, Jens Hedegaard Nielsen, Mike Nystrom, Eoin O’Farrell, Keita Otani, Karl Petersson, Luca Petit, Dima Pikulin, Mohana Rajpalke, Alejandro Alcaraz Ramirez, Katrine Rasmussen, David Razmadze, Yuan Ren, Ken Reneris, Ivan A. Sadovskyy, Lauri Sainiemi, Juan Carlos Estrada Saldaña, Irene Sanlorenzo, Emma Schmidgall, Cristina Sfiligoj, Sarat Sinha
The topological gap protocol (TGP) is a statistical test designed to identify a topological phase with high confidence and without human bias. It is used to determine a promising parameter regime for operating topological qubits. The protocol’s key metric is the probability of incorrectly identifying a trivial region as topological, referred to as the false discovery rate (FDR). Two recent manuscripts [arXiv:2502.19560, arXiv:2503.08944] engage with the topological gap protocol and its use in Phys. Rev. B 107, 245423 (2023) and Subsection S4.3 of the Supplementary Information for Nature 638, 651-655 (2025), although they do not explicitly dispute the main results of either one. We demonstrate that the objections in arXiv:2502.19560 and arXiv:2503.08944 are unfounded, and we uphold the conclusions of Phys. Rev. B 107, 245423 (2023) and Nature 638, 651-655 (2025). Specifically, we show that no flaws have been identified in our estimate of the false discovery rate (FDR). We provide a point-by-point rebuttal of the comments in arXiv:2502.19560 and arXiv:2503.08944.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Response to arXiv:2502.19560 and arXiv:2503.08944. 11 pages, 5 figures, 2 tables, code for reproduction
Torsional Hall Viscosity of Massive Chern Insulators: Magnetic Field and Momentum Deformations
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
Ioannis Matthaiakakis, Weizhen Jia, Raffael L. Klees, David Rodríguez Fernández, Zhuo-Yu Xian, René Meyer, Johanna Erdmenger, Ewelina M. Hankiewicz
This work focuses on the non-dissipative, parity-odd spin transport of (2 + 1)-dimensional relativistic electrons, generated by torsion, and the torsional Hall viscosity $ \zeta_{\mathrm{H}}$ . We first determine $ \zeta_{\mathrm{H}}$ for massive Dirac fermions in the presence of a constant electromagnetic field. We predict that the magnetic field induces a contribution to $ \zeta_{\mathrm{H}}$ competing with the one originating from the Dirac mass. Moreover, we quantify the impact on $ \zeta_{\mathrm{H}}$ originating from the band structure deformation quadratic in momentum terms that was proposed by Bernevig-Hughes-Zhang (BHZ). We find that the BHZ deformation enhances $ \zeta_{\mathrm{H}}$ in magnitude, but reverses its sign as compared to the standard massive Dirac fermion, indicating a Hall response in opposite direction to the typical Hall viscous force. Nevertheless, the torsional Hall viscosity still discriminates between topologically trivial and non-trivial regimes. Our results, hence, pave the way for a deeper understanding of hydrodynamic spin transport and its possible verification in experiments.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), High Energy Physics - Theory (hep-th)
14+6pages, 5 figures
Universal non-equilibrium dynamics of pure states and density-dependent thermalization in Sachdev-Ye-Kitaev model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
Rishik Perugu, Arijit Haldar, Sumilan Banerjee
Non-equilibrium dynamics of unentangled and entangled pure states in interacting quantum systems is crucial for harnessing quantum information and to understand quantum thermalization. We develop a general Schwinger-Keldysh (SK) field theory for non-equilibrium dynamics of pure states of fermions. We apply our formalism to study the time evolution of initial density inhomogeneity and multi-point correlations of pure states in the complex Sachdev-Ye-Kitaev (SYK) models. We demonstrate a remarkable universality in the dynamics of pure states in the SYK model. We show that dynamics of almost all pure states in a fixed particle number sector is solely determined by a set of universal large-$ N$ Kadanoff-Baym equations. Moreover, irrespective of the initial state the site- and disorder-averaged Green’s function thermalizes instantaneously, whereas local and non-local Green’s functions have finite thermalization rate. We support our large-$ N$ results through random-matrix theory (RMT) analysis. Furthermore, we show that the thermalization of an initial pure product state in the non-interacting SYK$ _2$ model is independent of fermion filling and an initial density inhomogeneity decays with weak but long lived oscillations due to dephasing. In contrast, the interacting SYK$ _{q\geq 4}$ model thermalizes slower than the non-interacting model and exhibits filling-dependent monotonic relaxation of initial inhomogeneity. For evolution of entangled pure states, we show that the initial entanglement is encoded in the non-local and/or multi-point quantum correlations that relax as the system thermalizes.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th)
20 pages, 9 figures
Novel phenomena in transition-metal oxide thin films and heterostructures with strong correlations and spin-orbit coupling
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Satoshi Okamoto, Narayan Mohanta, Ho Nyung Lee, Adriana Moreo, Elbio Dagotto
Transition-metal oxides have been a central subject of condensed matter physics for decades. In addition to novel electronic states driven by the influence of strong correlation, relativistic spin-orbit coupling effects have recently attracted much attention for their potential to explore topological phenomena. In this article, we review various experimental and theoretical studies on transition-metal oxides with focus on thin films and heterostructures where their physics is much influenced by correlation effects and spin-orbit coupling. The combination of the heterostructure geometry together with correlation and topology leads to a variety of novel states here reviewed. We also discuss perspectives for future research in this broad promising area.
Materials Science (cond-mat.mtrl-sci)
20 pages, 17 figures
Increasing Downshifting Luminescence Intensity Through an Extended Active Layer
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Miao Liu, Jinyang Liang, Fiorenzo Vetrone
The near-infrared (NIR) emission of rare-earth doped nanoparticles (RENPs), known as downshifting luminescence, has been extensively investigated in diverse applications from information technology to biomedicine. In promoting brightness and enriching the functionalities of the downshifting luminescence of RENPs, numerous studies have exploited inert shell to protect rare-earth dopants from surface quenchers. However, internal concentration quenching remains an unsolved puzzle when using higher dopant concentrations of rare-earth ions in an attempt to obtain brighter emission. Following a plethora of research involving core-shell structures, the interface has shown to be controllable, ranging from a well-defined, abrupt boundary to an obscure one with cation intermixing. By utilizing this inter-mixed core-shell property for the first time, we design a new architecture to create a homogeneous double-layer core-shell interface to extend the active layer, allowing more luminescent centers without severe concentration quenching. By systematically deploying the crystallinity of the starting core, shell growth dynamics, and dopant concentrations, the downshifting luminescence intensity of new archictecture achieves a 12-fold enhancement surpassing the traditional core-shell structure. These results provide deeper insight into the potential benefits of the intermixed core-shell structure, offering an effective approach to tackling the internal concentration quenching effect for highly boosted NIR optical performance.
Materials Science (cond-mat.mtrl-sci)
Demonstration of highly scaled AlScN ferroelectric diode memory with storage density > 100 Mbit/mm$^2$
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
Zekun Hu, Hyunmin Cho, Rajeev Kumar Rai, Kefei Bao, Yinuo Zhang, Yunfei He, Yaoyang Ji, Chloe Leblanc, Kwan-Ho Kim, Zirun Han, Zhen Qiu, Xingyu Du, Eric A. Stach, Roy Olsson, Deep Jariwala
Wurtzite nitride ferroelectric materials have emerged as promising candidates for next-generation memory applications due to their exceptional polarization properties and compatibility with conventional semiconductor processing techniques. Here, we demonstrate the first successful scaling of Aluminum Scandium Nitride (AlScN) ferroelectric diode (FeDiode) memory down to 50 nm device diameters while maintaining functional performance. Using a 20 nm Al0.64Sc0.36N ferroelectric layer, we investigate both metal-insulator-ferroelectric-metal (MIFM) and metal-ferroelectric-metal (MFM) architectures to optimize device performance. Our scaled devices exhibit a previously unreported size-dependent behavior, where switching voltage decreases while breakdown field increases with miniaturization, resulting in an enhanced breakdown-to-coercive field ratio exceeding 2.6 for the smallest structures. This favorable scaling behavior enables reliable operation at reduced dimensions critical for high-density applications. The MIFM devices demonstrate stable 3-bit non-volatile multistate behavior with clearly distinguishable resistance states and retention exceeding $ 5\times 10^5$ seconds. This combination of scalability and simple structure enables an effective memory density of 100 Mbit/mm$ ^2$ under feature size of 50 nm. By achieving 50 nm scaling with enhanced performance metrics, this work establishes AlScN-based FeDiode memory as a highly promising platform for next-generation non-volatile storage with potential for direct integration into CMOS technology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
4 figures and 1 table
Write Cycling Endurance Exceeding 1010 in Sub-50 nm Ferroelectric AlScN
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Hyunmin Cho, Yubo Wang, Chloe Leblanc, Yinuo Zhang, Yunfei He, Zirun Han, Roy H. Olsson III, Deep Jariwala
Wurtzite ferroelectrics, particularly aluminum scandium nitride (AlScN), have emerged as a promising materials platform for nonvolatile memories, offering high polarization values exceeding 100 uC/cm2. However, their high coercive fields (>3 MV/cm) have limited cycling endurance to ~107 cycles in previous reports. Here, we demonstrate unprecedented control of polarization switching in AlScN, achieving write cycling endurance exceeding 1010 cycles a thousand fold improvement over previous wurtzite ferroelectric benchmarks. Through precise voltage modulation in 45 nm thick Al0.64Sc0.36N capacitors, we show that while complete polarization reversal (2Pr ~ 200 uC/cm2) sustains ~108 cycles, partial switching extends endurance beyond 1010 cycles while maintaining a substantial polarization (>30 uC/cm2 for 2Pr). This exceptional endurance, combined with breakdown fields approaching 10 MV/cm in optimized 10 um diameter devices, represents the highest reported values for any wurtzite ferroelectric. Our findings establish a new paradigm for reliability in nitride ferroelectrics, demonstrating that controlled partial polarization and size scaling enables both high endurance and energy efficient operation.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
23 pages, 4 figures for manuscript 29 pages, 15 figures, 3 Informations for Supplementary Information
Role of the Direct-to-Indirect Bandgap Crossover in the ‘Reverse’ Energy Transfer Process
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Gayatri, Mehdi Arfaoui, Debashish Das, Tomasz Kazimierczuk, Natalia Zawadzka, Takashi Taniguchi, Kenji Watanabe, Adam Babinski, Saroj K. Nayak, Maciej R. Molas, Arka Karmakar
Energy transfer (ET) is a dipole-dipole interaction, mediated by the virtual photon. Traditionally, ET happens from the higher (donor) to lower bandgap (acceptor) material. However, in some rare instances, a ‘reverse’ ET can happen from the lower-to-higher bandgap material depending on the strong overlap between the acceptor photoluminescence (PL) and the donor absorption spectra. In this work, we report a reverse ET process from the lower bandgap MoS2 to higher bandgap WS2, due to the near ‘resonant’ overlap between the MoS2 B and WS2 A excitonic levels. Changing the MoS2 bandgap from direct-to-indirect by increasing the layer number results in a reduced ET rate, evident by the quenching of the WS2 PL emission. We also find that, at 300 K the estimated ET timescale of around 45 fs is faster than the reported thermalization of the MoS2 excitonic intervalley scattering (K+ to K-) time and comparable with the interlayer charge transfer time.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Two-field theory for phase coexistence of active Brownian particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-21 20:00 EDT
Pablo Perez-Bastías, Rodrigo Soto
Active Brownian particles (ABPs) serve as a minimal model of active matter systems. When ABPs are sufficiently persistent, they undergo a liquid-gas phase separation and, in the presence of obstacles, accumulate around them, forming a wetting layer. Here, we perform simulations of ABPs in a quasi-one-dimensional domain in the presence of a wall, studying the dynamics of the polarization field. On the course of time, we observe a transition from a homogeneous (where all particles are aligned) to a heterogeneous (where particles align only at the interface) polarization regime. We propose coarse-grained equations for the density and polarization fields based on microscopic and phenomenological arguments that correctly account for the observed phenomena.
Soft Condensed Matter (cond-mat.soft)
Adaptive AI decision interface for autonomous electronic material discovery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Yahao Dai, Henry Chan, Aikaterini Vriza, Fredrick Kim, Yunfei Wang, Wei Liu, Naisong Shan, Jing Xu, Max Weires, Yukun Wu, Zhiqiang Cao, C. Suzanne Miller, Ralu Divan, Xiaodan Gu, Chenhui Zhu, Sihong Wang, Jie Xu
AI-powered autonomous experimentation (AI/AE) can accelerate materials discovery but its effectiveness for electronic materials is hindered by data scarcity from lengthy and complex design-fabricate-test-analyze cycles. Unlike experienced human scientists, even advanced AI algorithms in AI/AE lack the adaptability to make informative real-time decisions with limited datasets. Here, we address this challenge by developing and implementing an AI decision interface on our AI/AE system. The central element of the interface is an AI advisor that performs real-time progress monitoring, data analysis, and interactive human-AI collaboration for actively adapting to experiments in different stages and types. We applied this platform to an emerging type of electronic materials-mixed ion-electron conducting polymers (MIECPs) – to engineer and study the relationships between multiscale morphology and properties. Using organic electrochemical transistors (OECT) as the testing-bed device for evaluating the mixed-conducting figure-of-merit – the product of charge-carrier mobility and the volumetric capacitance ({\mu}C\ast), our adaptive AI/AE platform achieved a 150% increase in {\mu}C\ast compared to the commonly used spin-coating method, reaching 1,275 F cm-1 V-1 s-1 in just 64 autonomous experimental trials. A study of 10 statistically selected samples identifies two key structural factors for achieving higher volumetric capacitance: larger crystalline lamellar spacing and higher specific surface area, while also uncovering a new polymer polymorph in this material.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI)
The configurational entropy of random trees
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-21 20:00 EDT
Pieter H. W. van der Hoek, Angelo Rosa, Ralf Everaers
We present a graph theoretical approach to the configurational statistics of random tree-like objects, such as randomly branching polymers. In particular, we show that Prüfer labelling provides: (i) direct access to the exact configurational entropy as a function of the tree composition, (ii) computable exact expressions for partition functions and important experimental observables for tree ensembles with controlled branching activity and (iii) an efficient sampling scheme for corresponding tree configurations and arbitrary static properties.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
14 pages, 5 main figures, 1 suppl. figure
Compensation-Like Temperature and Spin-Flip Switch in Strained Thulium Iron Garnet Thin Films: Tuning Sublattice Interactions for Ferrimagnetic Spintronics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Carlos C. Soares, Thiago J. A. Mori, Fanny Béron, Jagadeesh S. Moodera, Júlio C. Cezar, Jeovani Brandão, Gilvânia Vilela
Certain rare-earth iron garnet (RIG) thin films combine desirable properties such as low magnetic damping, high magnetostriction, and, in some cases, perpendicular magnetic anisotropy (PMA), making them attractive for spintronics applications. However, the interplay between their magnetic sublattices in confined films remains poorly explored, particularly the coupling between 3d and 4f electrons. Here, we investigate the magnetic properties of a 30 nm-thick thulium iron garnet (TmIG) thin film, where tensile strain promotes PMA. SQUID magnetometry and X-ray Magnetic Circular Dichroism measurements reveal a magnetization minimum near 50 K under moderate magnetic fields, leading to a compensation-like temperature (Tcomp-like), a feature absent in bulk TmIG. The presence of Tcomp-like is particularly relevant for controlling magnetization dynamics through compensation phenomena. Additionally, we observe a field-induced spin-flip transition in the Tm sublattice, where Tm moments reorient and align ferromagnetically concerning the Fe sublattices. This mechanism can be exploited for energy-efficient magnetization reversal. These findings provide new insights into strain-driven magnetic phenomena in rare-earth iron garnet thin films, highlighting the interplay between exchange interactions and anisotropy in confined geometries, which is crucial for the development of spintronic and magnonic devices.
Materials Science (cond-mat.mtrl-sci)
23 pages, 4 figures, submitted to ACS Applied Nano Materials
Charge transfer induced insulating state at antiperovskite/perovskite heterointerfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Ting Cui, Ying Zhou, Qianying Wang, Dongke Rong, Haitao Hong, Axin Xie, Jun-Jie Zhang, Qinghua Zhang, Can Wang, Chen Ge, Lin Gu, Shanmin Wang, Kuijuan Jin, Shuai Dong, Er-Jia Guo
Heterointerfaces have been pivotal in unveiling extraordinary interfacial properties and enabling multifunctional material platforms. Despite extensive research on all-oxide interfaces, heterointerfaces between different material classes, such as oxides and nitrides, remain underexplored. Here we present the fabrication of a high-quality Dirac metal antiperovskite Ni3InN, characterized by an extremely low temperature coefficient of resistivity, approximately 1.8\ast10^-8 {\Omega}\astcm/K, over a broad temperature range. Atomically sharp heterointerfaces between Ni3InN and SrVO3 were constructed, revealing intriguing interfacial phenomena. Leveraging layer-resolved scanning transmission electron microscopy and electron energy loss spectroscopy, we identified pronounced charge transfer across the well-ordered interface. Remarkably, this interfacial electron transfer from Ni3InN to SrVO3 induces an insulating interfacial layer and an emergent magnetic moment within the Ni3InN layer, consistent with first-principles calculations. These findings pave the way for novel electronic and spintronic applications by enabling tunable interfacial properties in nitride/oxide systems.
Materials Science (cond-mat.mtrl-sci)
15 pages; 4 figures
Forster resonance energy transfer in inhomogeneous and absorptive environment
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
L. S. Petrosyan, M. N. Noginov, T. V. Shahbazyan
We present an analytical model for Forster resonance energy transfer (FRET) between a donor and an acceptor placed in inhomogeneous and absorptive environment characterized by complex dielectric function, e.g., near a metal-dielectric structure. By extending the standard approach to FRET to include energy transfer (ET) channel to the environment, we show that, in the absence of plasmonic enhancement effects, the Forster radius, which defines the characteristic distance for efficient FRET, is reduced due to a competing ET process. We demonstrate that a reduction of the Forster radius can affect dramatically fluorescence from large ensemble of molecules whose emission kinetics is dominated by FRET-induced concentration quenching. Specifically, we perform numerical calculations for dye-doped polymer films deposited on top of metallic substrate to find that, for high dye concentrations, the emission kinetics slows down considerably, in sharp contrast to acceleration of single-molecule fluorescence. Furthermore, the calculated effective fluorescence decay rate exhibits non-monotonic behavior with varying film thickness, consistent with the experiment, indicating a non-trivial interplay between the metal quenching and concentration quenching mechanisms.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 5 figures
Sliding of liquid droplets on thin viscoelastic soft layers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-21 20:00 EDT
Menghua Zhao (MSC, LSIMM), Julien Dervaux (MSC), Tetsuharu Narita (LSIMM), François Lequeux (LSIMM), Laurent Limat (MSC), Matthieu Roché (MSC)
Soft substrates are deformed by liquid-vapor surface tension upon contact with liquid droplets, forming the well-known wetting ridge. This ridge dynamically propagates with the moving contact line and critically influences liquid spreading. Here, we experimentally investigate gravity-driven sliding dynamics of water droplets on vertically tilted silicone layers whose viscoleasticity is characterized by the Chasset-Thirion model with the exponent m. At low Bond numbers, the sliding velocity scales with droplet size as V S $ \sim$ D 2 m . While in the thin-film limit, velocity exhibits a pronounced power-law dependence on nominal substrate thickness, V S $ \sim$ $ \Pi$ (h) -1 m . We rationalize these observations by quantifying viscoelastic dissipation within the soft layer and balancing it against the gravitational driving force using an energy-conservation framework. Our findings offer novel avenues for designing advanced soft coatings, anti-fouling and self-cleaning surfaces, and biomedical devices.
Soft Condensed Matter (cond-mat.soft)
Target search optimization by threshold resetting
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-21 20:00 EDT
Arup Biswas, Satya N Majumdar, Arnab Pal
We introduce a new class of first passage time optimization driven by threshold resetting, inspired by many natural processes where crossing a critical limit triggers failure, degradation or transition. In here, search agents are collectively reset when a threshold is reached, creating event-driven, system-coupled simultaneous resets that induce long-range interactions. We develop a unified framework to compute search times for these correlated stochastic processes, with ballistic searchers as a key example uncovering diverse optimization behaviors. A cost function, akin to breakdown penalties, reveals that optimal resetting can forestall larger losses. This formalism generalizes to broader stochastic systems with multiple degrees of freedom.
Statistical Mechanics (cond-mat.stat-mech), Optimization and Control (math.OC), Probability (math.PR), Statistical Finance (q-fin.ST)
Effect of an electromagnetic field on the barrier crossing rate
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-21 20:00 EDT
L. R. Rahul Biswas, Shrabani Mondal, Bidhan Chandra Bag
We investigate the spectrum for the rate constant of an electric field-driven charged Brownian particle in the presence of a magnetic field (MF). For the cross fields with low or high values of the cyclotron frequency, an asymmetric splitting of the spectrum occurs with two peaks. Anharmonicity-induced additional splitting may appear around the lower resonating frequency at the intermediate strength of the applied MF. Another observation is that if the magnetic field is tilted from the z-direction, an additional peak appears between the two peaks. The position of the middle peak may be independent of the strength of the applied MF. In some cases, only one peak appears even in the presence of a magnetic field. We explain these observations considering the dynamics around the stable fixed point and determine the position of the peak in the spectrum for the rate constant as a function of the strength of the applied magnetic field. Thus the present study may find applications for tuning the conductivity of a solid electrolyte, which is very important in recent technology. Other applications may be in areas such as electromagnetic field-induced modulation of (a) thermally activated tunneling ionization, (b) thermally stimulated ionization, etc.
Statistical Mechanics (cond-mat.stat-mech)
Extracting flow stress surfaces of pristine materials using deformation paths in MD simulations
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Eliott T. Dubois, Paul Lafourcade, Jean-Bernard Maillet
Accurate simulation of deformation processes at the atomic scale is critical for predicting the mechanical response of materials and particularly the calculation of directional flow stresses. This work presents a method for applying arbitrary deformation paths in LAMMPS while adhering to its convention that supercell periodic vectors a, b are aligned such that a coincides with the x-axis and b lies in the (x,y) plane. This method is particularly relevant for materials with low crystal symmetry and also for exploring non uniaxial deformations. The first step of the method consists in generating the simulation frame tensor’s time evolution upon any deformation, which may initially violate LAMMPS alignment constraints. This constraint is then overcome by the application of a rigid body rotation to realign the tensor with LAMMPS’s convention, ensuring valid periodic boundary conditions. The resulting lengths and tilt factors from the rotated tensor are expressed analytically using third-order polynomials and applied to the simulation cell using the fix deform command. The present approach versatility is validated with the calculation of directional flow stresses for various materials upon constant volume shear, tension and compression, demonstrating its effectiveness in simulations involving complex deformation scenarios and diverse crystal structures. The flow stress surface extracted from these simulations are finally analyzed as the fingerprint of all deformation mechanisms occurring in the material.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Emergence of rotating clusters in active Brownian particles with visual perception
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-21 20:00 EDT
Radha Madhab Chandra, Alan Biju John, A. V. Anil Kumar
We examine the group formation and subsequent dynamics of active particles which are equipped with a visual perception using Langevin dynamics simulations. These particles possess an orientational response to the position of the nearest neighbours which are within a vision cone of these particles. We observe the emergence of rotating clusters when the visual perception of the particles are in the intermediate range. We have found that the persistent motion of these active particles are intimately correlated with the emerging structures by analysing the persistence probability as well as the orientational correlation function. For rotating clusters, the persistent probability is found to be very quickly decaying and orientational correlation function shows oscillatory behaviour.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
9 pages, 9 figures
Coplanar order induced by emergent frustration
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
Zehui Deng, Lu Liu, Wenan Guo, Hai-Qing Lin
Traditional frustration arises from the conflict between the spin alignments due to the geometry or the nature of the interactions. Here, we demonstrate a novel form of frustration, dubbed ``emergent frustration’’, which is induced by the symmetry that emerges at the phase transition point of a quantum spin model devoid of geometric frustration. We study the two-dimensional bipartite chequerboard $ J$ -$ Q$ model, which hosts the antiferromagnetic (AFM) state to the plaquette-singlet solid state (PSS) phase transition detected in the Shastry-Sutherland compound SrCu$ _2({\rm BO}_3)_2$ . By analyzing the scaling behavior of the Rényi entanglement entropy with smooth boundaries at the transition point, we observe an unexpected scaling behavior, which indicates that the number of Goldstone modes is five. We explain this by proposing a novel scenario in which the system is described by an effective quantum rotor Hamiltonian with a three-sublattice geometry that frustrates collinear order while supporting coplanar order. Such a three-sublattice geometry arises from the emergent symmetry of coexisting orders, which may also occur at the AFM-PSS transition point of SrCu$ _2({\rm BO}_3)_2$ . Therefore, experimental investigations are warranted.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
7 pages, 3 figures
Long-range electron coherence in Kagome metals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
Chunyu (Mark)Guo, Kaize Wang, Ling Zhang, Carsten Putzke, Dong Chen, Maarten R. van Delft, Steffen Wiedmann, Fedor F. Balakirev, Ross D. McDonald, Martin Gutierrez-Amigo, Manex Alkorta, Ion Errea, Maia G. Vergniory, Takashi Oka, Roderich Moessner, Mark H. Fischer, Titus Neupert, Claudia Felser, Philip J.W. Moll
The wave-like nature of electrons lies at the core of quantum mechanics, distinguishing them from classical particles. Landmark experiments have revealed phase coherence of mobile electrons within solids, such as Aharonov-Bohm interference in mesoscopic rings. However, this coherence is typically limited by numerous environmental interactions. Controlling and ideally mitigating such decoherence remains a central challenge in condensed matter physics. Here, we report magnetoresistance oscillations in mesoscopic pillars of the Kagome metal CsV$ _3$ Sb$ _5$ for fields applied parallel to the Kagome planes. Their periodicity is independent of materials parameters, simply given by the number of flux quanta $ h/e$ threading between adjacent Kagome layers akin to an atomic-scale Aharonov-Bohm interferometer. Intriguingly they occur under conditions not favorable for typical interference in solids, at temperatures above 20 K and in micrometer-scale devices well exceeding the single-particle mean free path. Further, the oscillations exhibit non-analytic field-angle dependence and scale consistently with a broad range of key electronic responses in CsV$ _3$ Sb$ _5$ , pointing to a cooperative mechanism that establishes intrinsic coherence. Our findings provide new insights into the debated origin of correlated order in CsV$ _3$ Sb$ _5$ and establish Kagome metals as a promising platform for interaction-stabilized long-range electron coherence - crucial for both fundamental studies and technological advancements in quantum interference in metallic systems.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
Chiral Locking of Magnon Flow and Electron Spin Accumulation in Their Near-Field Radiative Spin Transfer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
We report a non-contact mechanism for directional injection of magnons in magnetic films when driven by a spin accumulation $ \pmb{\mu}_s$ of electrons of a nearby metallic layer, governed by the long-range dipolar coupling between magnons and electron spins, which spontaneously generates a magnon current $ {\bf J}_m$ flowing in the film plane. Crucially, in such near-field radiative spin transfer, the magnon flow $ {\bf J}_m$ is always perpendicular to the spin accumulation $ \pmb{\mu}_s$ , showing a universal chiral locking relation. The spin injection is efficient even when $ \pmb{\mu}_s$ is parallel to the magnetization, a feature breaking the limitation of the spin transfer by contact exchange interaction. Our findings reveal the critical role of dipolar chirality in driving the magnon thermal current and paving the way for the functional design of magnonic devices based on near-field radiative spin transfer.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Pressure dependent ab initio study of the physical properties of hexagonal BeB2C: a possible high-Tc superconductor
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Ruman Ali, Md. Enamul Haque, Jahid Hassan, M. A. Masum, R. S. Islam, S. H. Naqib
This study uses the Density Functional Theory to explore the pressure dependent properties of hexagonal BeB2C. The metallic nature of BeB2C was substantiated at ambient pressure, with pressure induced alterations in electronic band structure and Fermi surface topology suggesting a potential for tunability across various applications. The phonon dispersion and phonon density of states show the dynamical stability under pressure. The thermophysical properties are also investigated under varying pressure conditions. Finally, the exploration of superconducting properties found that the transition temperature is in good agreement with previously reported values, and illustrated that beB2C holds considerable promise as a high-temperature superconductor, with pressure augmenting its superconducting properties.
Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
The correspondence between the Adam-Gibbs and the Rosenfield relations
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-21 20:00 EDT
In this paper, we derive both the Adam-Gibbs and the Rosenfield relations from the microscopic point of view and compare them with the numerical calculation for one and two dimensional systems. The comparison shows there is an excellent agreement between theoretical and numerical calculations for their valid zones (in terms of the thermodynamic temperature) as suggested by experiments. It implies that there may be a transition temperature at which the two relations correspond to each other. We derive a relation to calculate it. Then, we generalize the Rosenfield relation for configurational thermodynamic entropy like quantity(TELQ) and time-dependent Shanon information entropy. At the same time, using a description with a fictitious Hamiltonian, we show that time-dependent configurational Shanon information entropy for a thermodynamic system (of Brownian particles) which is characterized by the absolute temperature, can not be recognized as thermodynamic entropy. At best, it can be identified as a thermodynamic entropy-like quantity. Furthermore, the description based on the fictitious Hamiltonian may lead to the conclusion that the correspondence between the Shanon information entropy and thermodynamic entropy is not a singular feature at equilibrium. It may be a continuation of the correspondence between the information entropy and the thermodynamic entropy-like quantity. Thus, the present study appears to offer important justification for the postulate that the Shannon entropy at steady state may be regarded as a thermodynamic entropy. This postulate holds significant importance in the framework of stochastic thermodynamics.
Statistical Mechanics (cond-mat.stat-mech)
Single-molecule electroluminescence: crossover from weak to strong coupling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
Andrés Bejarano, Moritz Frankerl, Rémi Avriller, Thomas Frederiksen, Fabio Pistolesi
We develop a microscopic model to investigate current-induced light emission in single-molecule tunnel junctions, where a two-level system interacts with a plasmonic field. Using the quantum master equation, we explore the transition from weak to strong plasmon-molecule coupling, identifying three distinct regimes governed by cooperativity, which quantifies the interplay between interaction strength and losses. Our findings establish a framework to detect strong coupling, unveiling resonance-dependent features in the emission spectrum and photon correlations.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Electronic structure and x-ray magnetic circular dichroism in the quadruple perovskite CaCu3Re2Fe2O12
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
L.V. Bekenov, D.V. Mazur, B.F. Zhuravlev, S.V. Moklyak, Yu.N. Kucherenko, V.N. Antonov
We have studied the electronic and magnetic properties of the A- and B-site-ordered perovskite CaCu3Re2Fe2O12 within the density-functional theory using the generalized gradient approximation (GGA) with the consideration of strong Coulomb correlations (GGA+U ) in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band structure method. We have calculated the x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD) spectra at the Cu, Fe, Re L2,3 and O K edges. The calculated results are in good agreement with experiment. We show that the GGA+U method produces better agreement with the experimental spectra if Hubbard U is applied to Cu and Fe sites.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 6 figures
Fermi surface evolution in Weyl semimetal t-PtBi$_2$ probed by transverse transport properties
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-21 20:00 EDT
F. Caglieris (1), M. Ceccardi (2,1,3), D. Efremov (3), G. Shipunov (3), S. Aswartham (3), A. Veyrat (3), J. Dufouleur (3,5), D. Marré (2,1), B. Büchner (3,4,5), C. Hess (3,5,6) ((1) CNR-SPIN, Genova, Italy (2) University of Genoa, Genova, Italy, (3) Leibniz-Institute for Solid State and Materials Research IFW-Dresden, Dresden, Germany (4) Institut für Festkörperphysik, TU Dresden, Dresden, Germany, (5) Center for Transport and Devices, TU Dresden, Dresden, Germany, (6) Fakultät für Mathematik und Naturwissenschaften, Bergische Universität Wuppertal, Wuppertal, Germany)
The combination of non-trivial topology and superconductivity opens to novel quantum devices. The discovery of intrinsic materials where such properties appear together represents a frontier in modern condensed matter physics. Trigonal PtBi$ _2$ has recently emerged as a possible candidate, being the first example of superconducting type-I Weyl semimetal. However, several aspects of this promising compound still need to be unveiled, concerning its complicated band structure, the actual role of Weyl points in determining its electronic properties and the nature of the superconducting transition. In this work, we experimentally investigated a t-PtBi$ _2$ single crystal by means of the Hall and Nernst effects. In particular, we revealed a change of regime in its electronic properties, which is compatible with a temperature and magnetic field evolution of hole-like pockets in the Fermi Surface.
Superconductivity (cond-mat.supr-con)
Exploring Charge Density Waves in two-dimensional NbSe$_2$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Norma Rivano, Francesco Libbi, Chuin Wei Tan, Christopher Cheung, Jose Lado, Arash Mostofi, Philip Kim, Johannes Lischner, Adolfo O. Fumega, Boris Kozinsky, Zachary A. H. Goodwin
Niobium diselenide (NbSe$ _2$ ) has garnered attention due to the coexistence of superconductivity and charge density waves (CDWs) down to the monolayer limit. However, realistic modeling of CDWs-accounting for effects such as layer number, twist angle, and strain-remains challenging due to the prohibitive cost of first-principles methods. To address this, we develop machine learning interatomic potentials (MLIPs), based on the Allegro architecture-an E(3)-equivariant model – specifically tailored to capture subtle CDW effects in NbSe$ _2$ . These MLIPs enable efficient exploration of commensurate and incommensurate CDW phases, as well as the dimensional dependence of the transition temperature, evaluated using the Stochastic Self-Consistent Harmonic Approximation (SSCHA). Our findings reveal a strong sensitivity of CDWs to stacking and layer number, and a slight suppression of the transition temperature with increasing thickness. This work opens new possibilities for studying and tuning CDWs in NbSe$ _2$ and other 2D systems, with implications for electron-phonon coupling, superconductivity, and advanced materials design.
Materials Science (cond-mat.mtrl-sci), Superconductivity (cond-mat.supr-con)
Comment on “The inconvenient truth about flocks” by Chen et al
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-04-21 20:00 EDT
We hope here to provide the community with a convenient account of our viewpoint on the claims made by Chen et al. about our results on two-dimensional polar flocks.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
2 pages, 1 figure. Comment on arXiv:2503.17064
Density functional theory of resonant inelastic x-ray scattering in the quasi-one-dimensional dimer iridate Ba$_5$AlIr$2$O${11}$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
D.A. Kukusta, L.V. Bekenov, V.N. Antonov
We have investigated the electronic structure of Ba$ _5$ AlIr$ _2$ O$ _{11}$ within the density functional theory using the generalized gradient approximation while considering strong Coulomb correlations in the framework of the fully relativistic spin-polarized Dirac linear muffin-tin orbital band-structure method. We have investigated the x-ray absorption spectra, x-ray magnetic circular dichroism, and resonant inelastic x-ray scattering spectra (RIXS) at the Ir $ K$ , $ L_3$ , $ M_3$ , $ M_5$ and O K edges. The calculated results are in good agreement with experimental data. The RIXS spectrum of Ba$ 5$ AlIr$ 2$ O$ {11}$ at the Ir $ L_3$ edge possesses sharp twelve features below 1.5 eV corresponding to transitions within the Ir t2g levels. The excitations located from 2 to 4 eV are due to $ t{2g} \to e_g$ and $ O{2p} \to t{2g}$ transitions. The high energy peaks situated at 5-11 eV appear due to charge transfer transitions. The theory reproduces well the shape and polarization dependence of the oxygen O K RIXS spectrum. We have found that the dependence of the RIXS spectrum at the oxygen K edge on the incident photon energy and the momentum transfer vector Q is much stronger than the corresponding dependence at the Ir $ L_3$ edge
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 17 figures
Rabi Oscillations of Strongly Driven Bose Polarons
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-04-21 20:00 EDT
Understanding the dynamical behavior of quasiparticles is essential for uncovering novel quantum many-body phenomena. Among these phenomena, the polaron in ultracold atomic gases has attracted considerable interest due to its precise controllability. By engineering the underlying Hamiltonian, polarons serve as a versatile platform for studying both equilibrium properties and non-equilibrium dynamics. In this work, we investigate the quantum dynamics of strongly driven Bose polarons, where minority atoms are described as mobile impurities with spin-1/2, and majority atoms are bosons. The spin-$ \uparrow$ impurity interacts with majority atoms through a tunable scattering length $ a$ , while the spin-$ \downarrow$ impurity remains non-interacting. After turning on the Rabi coupling, we calculate the evolution of the total magnetization using a trial wavefunction. We identify the exhibition of anomalous Rabi oscillation and steady-state magnetization for $ a>0$ , due to the interplay between attractive and repulsive polarons. Our results provide a concrete example that illustrates how Rabi oscillations are dressed by system-environment coupling.
Quantum Gases (cond-mat.quant-gas)
8 pages, 5 figures + supplementary material
Probing Majorana localization of a phase-controlled three-site Kitaev chain with an additional quantum dot
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
Alberto Bordin, Florian J. Bennebroek Evertsz’, Bart Roovers, Juan D. Torres Luna, Wietze D. Huisman, Francesco Zatelli, Grzegorz P. Mazur, Sebastiaan L. D. ten Haaf, Ghada Badawy, Erik P. A. M. Bakkers, Chun-Xiao Liu, Ruben Seoane Souto, Nick van Loo, Leo P. Kouwenhoven
Few-site implementations of the Kitaev chain offer a minimal platform to study the emergence and stability of Majorana bound states. Here, we realize two- and three-site chains in semiconducting quantum dots coupled via superconductors, and tune them to the sweet spot where zero-energy Majorana modes appear at the chain ends. We demonstrate control of the superconducting phase through both magnetic field and sweet-spot selection, and fully characterize the excitation spectrum under local and global perturbations. All spectral features are identified using the ideal Kitaev chain model. To assess Majorana localization, we couple the system to an additional quantum dot. The absence of energy splitting at the sweet spot confirms the high quality of the Majorana modes, despite the minimal size of the chains.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Stability of flocking in the reciprocal two-species Vicsek model: Effects of relative population, motility, and noise
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-04-21 20:00 EDT
Aditya Kumar Dutta, Matthieu Mangeat, Heiko Rieger, Raja Paul, Swarnajit Chatterjee
Natural flocks need to cope with various forms of heterogeneities, for instance, their composition, motility, interaction, or environmental factors. Here, we study the effects of such heterogeneities on the flocking dynamics of the reciprocal two-species Vicsek model [Phys. Rev. E 107, 024607 (2023)], which comprises two groups of self-propelled agents with anti-aligning inter-species interactions and exhibits either parallel or anti-parallel flocking states. The parallel and anti-parallel flocking states vanish upon reducing the size of one group, and the system transitions to a single-species flock of the majority species. At sufficiently low noise (or high density), the minority species can exhibit collective behavior, anti-aligning with the liquid state of the majority species. Unequal self-propulsion speeds of the two species strongly encourage anti-parallel flocking over parallel flocking. However, when activity landscapes with region-dependent motilities are introduced, parallel flocking is retained if the faster region is given more space, highlighting the role of environmental constraints. Under noise heterogeneity, the colder species (subjected to lower noise) attain higher band velocity compared to the hotter one, temporarily disrupting any parallel flocking, which is subsequently restored. These findings collectively reveal how different forms of heterogeneity, both intrinsic and environmental, can qualitatively reshape flocking behavior in this class of reciprocal two-species models.
Statistical Mechanics (cond-mat.stat-mech)
16 pages, 18 figures
Orientation attractors in velocity gradient driven processes for large plastic deformations of crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Jalal Smiri, Oguz Umut Salman, Ioan R. Ionescu
We study lattice orientation attractors, also referred to as preferred or ideal orientations, in crystalline materials, and how they can be used to predict the final texture of polycrystals after manufacturing processes. By treating Crystal Plasticity (CP) in an Eulerian framework, rather than traditional Lagrangian approaches, we overcome the significant challenges associated with lattice distortion, enabling accurate simulations of material behavior under large deformations. This Eulerian perspective allows us to track the evolution of crystallographic orientations directly in the spatial domain, providing crucial insights into texture development. The CP models employed here capture the microstructural evolution in both mono- and polycrystalline materials, with particular emphasis on velocity gradient driven processes. Our linear stability analysis strategy, while applicable to general CP formulations, is demonstrated using a simplified rigid-(visco)-plastic 2-D model with three slip systems. This approach successfully predicts the lattice orientation attractors for very large strains (exceeding 50$ %$ ) by analyzing how different slip systems interact under applied loads. Three numerical simulations illustrate the theory’s effectiveness: polycrystal deformation under homogeneous velocity gradient loading, void evolution in a monocrystal under non-homogeneous loading, and slip band formation during uni-axial traction. High-resolution CP simulations, enhanced through re-meshing techniques, further validate our findings on how initial crystallographic orientations, deformation mechanisms, and loading conditions affect the evolution of orientation attractors and ultimate crystal texture.
Materials Science (cond-mat.mtrl-sci)
arXiv admin note: text overlap with arXiv:2504.03565
Excitonic effects in phonons: reshaping the graphene Kohn anomalies and lifetimes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Alberto Guandalini, Giovanni Caldarelli, Francesco Macheda, Francesco Mauri
We develop an ab initio framework that captures the impact of electron-electron and electron-hole interactions on phonon properties. This enables the inclusion of excitonic effects in the optical phonon dispersions and lifetimes of graphene, both near the center ($ \Gamma$ ) and at the border (K) of the Brillouin zone, at phonon momenta relevant for Raman scattering and for the onset of the intrinsic electrical resistivity. Near K, we find a phonon red-shift of ~150 $ cm^{-1}$ and a 10x enhancement of the group velocity, together with a 5x increase in linewidths due to a 26x increase of the electron-phonon matrix elements. These effects persist for doping $ 2E_{F} < {\hbar}{\omega}_{ph}$ and are quenched at higher dopings. Near $ \Gamma$ , the excitonic effects are minor because of the gauge field nature of the electron-phonon coupling at small phonon momentum.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Isotropic and anisotropic spin-dependent transport in epitaxial Fe$_3$Si
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-04-21 20:00 EDT
Nozomi Soya, Michihiro Yamada, Kohei Hamaya, Kazuya Ando
We investigate spin-dependent transport phenomena in epitaxially grown Fe$ _3$ Si films, focusing on the anisotropic magnetoresistance (AMR), planar Hall effect (PHE), anomalous Hall effect (AHE), and spin Hall effect (SHE). While the sign and magnitude of the AMR and PHE depend on the current orientation relative to the crystallographic axes, the AHE and SHE remain nearly independent of the current orientation. The anisotropic AMR and PHE are attributed to current and magnetization dependent local band properties, including band crossing/anticrossing at specific $ k$ points. In contrast, the isotropic AHE and SHE arise from the Berry curvature integrated over the entire Brillouin zone, which cancels local variations. These findings highlight the interplay between symmetry, band structure, and magnetization in the spin-dependent transport phenomena.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Generating new coordination compounds via multireference simulations, genetic algorithms and machine learning: the case of Co(II) molecular magnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Lion Frangoulis, Zahra Khatibi, Lorenzo A. Mariano, Alessandro Lunghi
The design of coordination compounds with target properties often requires years of continuous feedback loop between theory, simulations and experiments. In the case of magnetic molecules, this conventional strategy has indeed led to the breakthrough of single-molecule magnets with working temperatures above nitrogen’s boiling point, but at significant costs in terms of resources and time. Here, we propose a computational strategy able to accelerate the discovery of new coordination compounds with desired electronic and magnetic properties. Our approach is based on a combination of high-throughput multireference ab initio methods, genetic algorithms and machine learning. While genetic algorithms allow for an intelligent sampling of the vast chemical space available, machine learning reduces the computational cost by pre-screening molecular properties in advance of their accurate and automated multireference ab initio characterization. Importantly, the presented framework is able to generate novel organic ligands and explore chemical motifs beyond those available in pre-existing structural databases. We showcase the power of this approach by automatically generating new Co(II) mononuclear coordination compounds with record magnetic properties in a fraction of the time required by either experiments or brute-force ab initio approaches
Materials Science (cond-mat.mtrl-sci), Neural and Evolutionary Computing (cs.NE), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Optical engineering and detection of magnetism in moiré semiconductors
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-04-21 20:00 EDT
Tsung-Sheng Huang, Andrey Grankin, Yu-Xin Wang, Mohammad Hafezi
We present a general framework for optically inducing, controlling, and probing spin states in moiré systems. In particular, we demonstrate that applying Raman optical drives to moiré transition metal dichalcogenide bilayers can realize a class of spin models, with magnetic interactions tunable via the optical parameters. The resulting interaction anisotropy, controlled by the polarizations of the drives, enables access to magnetic states that are inaccessible in undriven moiré bilayers. Furthermore, we establish direct connections between the resulting spin correlations and experimentally observable optical signals. Our work paves the way for future studies on the optical control and detection on strongly correlated quantum systems.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Quantum Physics (quant-ph)
Emergent chiral toplogical point gaps in a non-Hermitian quasiperiodic Su-Schrieffer-Heeger model
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-04-21 20:00 EDT
Zhi-Bin Liang, Shan-Zhong Li, Runze Li, Zhi Li
We study a quasiperiodic Su-Schrieffer-Heeger lattice with staggered on-site gain-loss. The results reveal that on-site staggered gain-loss can effectively induce non-Hermitian topological gap without introducing imaginary phase. Further analysis exhibits that five different processes of topological phase transitions, including topological re-entrant phenomena, with the gain-loss intensity increasing. In addition, through the analysis of inverse participation ratios, normalized participation ratios, winding number and other indicators, we find that topological phase transitions occur synchronically with localized phase transitions. Finally, by investigating the properties of dual space eigenfunction, we reveal that the non-Hermitian topological point gaps predicted in this paper are chiral point gaps, which have a pair of skin modes along opposite directions simultaneously.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Lattice Quantum Geometry Controlling 118 K Multigap Superconductivity in Heavily Overdoped CuBa2Ca3Cu4O10+d
New Submission | Superconductivity (cond-mat.supr-con) | 2025-04-21 20:00 EDT
Gaetano Campi, Massimiliano Catricala, Giuseppe Chita, Luisa Barba, Luchuan Shi, Jianfa Zhao, Changing Jin, Antonio Bianconi
Synchrotron X-ray diffraction has been used to study the thermal structure evolution in CuBa2Ca3Cu4O10+d (Cu1234), a superconductor which exhibits a high critical temperature (Tc 118 K), high critical current density and large upper critical magnetic field. The lattice geometry at nanoscale of this cuprate belongs to the class of natural heterostructures at atomic limit like the artificial high Tc superlattices made of interface space charge in Mott insulator units intercalated by metal units. Temperature-dependent lattice parameters reveal a distinct structural transition at TC characterized by a drop of the c-axis and in plane Cu-O negative thermal expansion below TC. These results provide clear evidence of lattice reorganization associated with the chemical potential changes due to the opening of multiple superconducting gaps. Additionally, evidence for oxygen defects rearrangement is observed at temperatures above 200 K. We construct a phase diagram correlating temperature, the c/a axis ratio, and in plane Cu-O strain, identifying regions associated with gaps opening and oxygen rearrangement. These findings provide new insights into how lattice geometry control superconductivity to inform the material design of advanced nanoscale superconducting artificial quantum heterostructures.
Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
16 pages, 4 figures
Accurate Point Defect Energy Levels from Non-Empirical Screened Range-Separated Hybrid Functionals: the Case of Native Vacancies in ZnO
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-04-21 20:00 EDT
Sijia Ke, Stephen E. Gant, Leeor Kronik, Jeffrey B. Neaton
We use density functional theory (DFT) with non-empirically tuned screened range-separated hybrid (SRSH) functionals to calculate the electronic properties of native zinc and oxygen vacancy point defects in ZnO, and we predict their defect levels for thermal and optical transitions in excellent agreement with available experiments and prior calculations that use empirical hybrid functionals. The ability of this non-empirical first-principles framework to accurately predict quantities of relevance to both bulk and defect level spectroscopy enables high-accuracy DFT calculations with non-empirical hybrid functionals for defect physics, at a reduced computational cost.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)