CMP Journal 2025-02-07
Statistics
Nature Materials: 2
Nature Physics: 1
Science: 5
Physical Review Letters: 15
Physical Review X: 2
arXiv: 61
Nature Materials
Iterative sublattice amorphization facilitates exceptional processability in inorganic semiconductors
Original Paper | Electronic devices | 2025-02-06 19:00 EST
Yuechu Wang, Airan Li, Youran Hong, Tianqi Deng, Pan Deng, Yi Huang, Kai Liu, Jiangwei Wang, Chenguang Fu, Tiejun Zhu
Cold-forming processing is a crucial means for the cost-effective production of metal and alloy products. However, this process often results in catastrophic fracture when applied to most inorganic semiconductors owing to their inherent brittleness. Here we report the unique room-temperature plastic deformation mechanism involving sublattice amorphization coupled with Ag-ion diffusion in inorganic semiconductors Ag2Te1-xSx (0.3 ≤ x ≤ 0.6), and an ultrahigh extensibility of up to 10,150%. Once subject to external stress, the crystalline Te/S sublattice undergoes a uniform transformation into an amorphous state, whereas the Ag cations continuously bond with Te/S anions, endowing bulk Ag2Te1-xSx with exceptional plastic deformability. Remarkably, even slight polishing can induce sublattice amorphization in the surface layers. Furthermore, this sublattice amorphization can be reversed to crystals through simple annealing, enlightening the iterative sublattice amorphization strategy, with which metal-like wire drawing, curving, forging and ultrahigh ductility have been obtained in bulk Ag2Te1-xSx at room temperature. These results highlight sublattice amorphization as a critical plastic deformation mechanism in silver chalcogenide inorganic semiconductors, which will facilitate their applications in flexible electronics and drive further exploration of more plastic inorganic semiconductors.
Electronic devices, Mechanical properties, Semiconductors
Room-temperature anisotropic in-plane spin dynamics in graphene induced by PdSe2 proximity
Original Paper | Electronic and spintronic devices | 2025-02-06 19:00 EST
Juan F. Sierra, Josef Světlík, Williams Savero Torres, Lorenzo Camosi, Franz Herling, Thomas Guillet, Kai Xu, Juan Sebastián Reparaz, Vera Marinova, Dimitre Dimitrov, Sergio O. Valenzuela
van der Waals heterostructures provide a versatile platform for tailoring electrical, magnetic, optical and spin transport properties via proximity effects. Hexagonal transition metal dichalcogenides induce valley Zeeman spin-orbit coupling in graphene, creating spin lifetime anisotropy between in-plane and out-of-plane spin orientations. However, in-plane spin lifetimes remain isotropic due to the inherent heterostructure's three-fold symmetry. Here we demonstrate that pentagonal PdSe2, with its unique in-plane anisotropy, induces anisotropic gate-tunable spin-orbit coupling in graphene. This enables a tenfold modulation of spin lifetimes at room temperature, depending on the in-plane spin orientation. Moreover, the directional dependence of the spin lifetimes, along the three spatial directions, reveals a persistent in-plane spin texture component that governs the spin dynamics. These findings advance our understanding of spin physics in van der Waals heterostructures and pave the way for designing topological phases in graphene-based heterostructures in the strong spin-orbit coupling regime.
Electronic and spintronic devices, Electronic devices, Electronic properties and devices, Spintronics
Nature Physics
Unified percolation scenario for the α and β processes in simple glass formers
Original Paper | Atomistic models | 2025-02-06 19:00 EST
Liang Gao, Hai-Bin Yu, Thomas B. Schrøder, Jeppe C. Dyre
Given the vast differences in interaction details, describing the dynamics of structurally disordered materials in a unified theoretical framework presents a fundamental challenge to condensed-matter physics and materials science. Here we numerically investigate a double-percolation scenario for the two most important relaxation processes of supercooled liquids and glasses, the so-called α and β relaxations. For several simple glass formers, we find that when monitoring the dynamic shear modulus as temperature is lowered from the liquid state, percolation of immobile particles takes place at the temperature locating the α process. Mirroring this, upon continued cooling into the glass state, the mobile-particle percolation transition pinpoints a β process whenever the latter is well separated from the main (α) process. For two-dimensional systems under the same conditions, percolation of mobile and immobile particles occurs nearly simultaneously, and no β relaxation can be identified. Our findings suggest that a general description of glassy dynamics should be based on a percolation perspective.
Atomistic models, Structure of solids and liquids
Science
Sequence-dependent activity and compartmentalization of foreign DNA in a eukaryotic nucleus
Research Article | Epigenetics | 2025-02-07 03:00 EST
Léa Meneu, Christophe Chapard, Jacques Serizay†, Alex Westbrook, Etienne Routhier, Myriam Ruault, Manon Perrot, Alexandros Minakakis, Fabien Girard, Amaury Bignaud, Antoine Even, Géraldine Gourgues, Domenico Libri, Carole Lartigue, Aurèle Piazza, Agnès Thierry, Angela Taddei, Frédéric Beckouët, Julien Mozziconacci, Romain Koszul
In eukaryotes, DNA-associated protein complexes coevolve with genomic sequences to orchestrate chromatin folding. We investigate the relationship between DNA sequence and the spontaneous loading and activity of chromatin components in the absence of coevolution. Using bacterial genomes integrated into Saccharomyces cerevisiae, which diverged from yeast more than 2 billion years ago, we show that nucleosomes, cohesins, and associated transcriptional machinery can lead to the formation of two different chromatin archetypes, one transcribed and the other silent, independently of heterochromatin formation. These two archetypes also form on eukaryotic exogenous sequences, depend on sequence composition, and can be predicted using neural networks trained on the native genome. They do not mix in the nucleus, leading to a bipartite nuclear compartmentalization, reminiscent of the organization of vertebrate nuclei.
The essential genome of Plasmodium knowlesi reveals determinants of antimalarial susceptibility
Research Article | Malaria | 2025-02-07 03:00 EST
Brendan Elsworth, Sida Ye, Sheena Dass, Jacob A. Tennessen, Qudseen Sultana, Basil T. Thommen, Aditya S. Paul, Usheer Kanjee, Christof Grüring, Marcelo U. Ferreira, Marc-Jan Gubbels, Kourosh Zarringhalam, Manoj T. Duraisingh
Measures to combat the parasites that cause malaria have become compromised because of reliance on a small arsenal of drugs and emerging drug resistance. We conducted a transposon mutagenesis screen in the primate malaria parasite Plasmodium knowlesi, producing the most complete classification of gene essentiality in any Plasmodium spp. to date, with the resolution to define truncatable genes. We found conservation in the druggable genome between Plasmodium spp. and divergences in mitochondrial metabolism. Perturbation analyses with the frontline antimalarial artemisinin revealed modulators that both increase and decrease drug susceptibility. Our findings aid prioritization of drug and vaccine targets for the Plasmodium vivax clade and reveal mechanisms of resistance that can inform therapeutic development.
Supersaturation mutagenesis reveals adaptive rewiring of essential genes among malaria parasites
Research Article | Malaria | 2025-02-07 03:00 EST
Jenna Oberstaller, Shulin Xu, Deboki Naskar, Min Zhang, Chengqi Wang, Justin Gibbons, Camilla Valente Pires, Matthew Mayho, Thomas D. Otto, Julian C. Rayner, John H. Adams
Malaria parasites are highly divergent from model eukaryotes. Large-scale genome engineering methods effective in model organisms are frequently inapplicable, and systematic studies of gene function are few. We generated more than 175,000 transposon insertions in the Plasmodium knowlesi genome, averaging an insertion every 138 base pairs, and used this "supersaturation" mutagenesis to score essentiality for 98% of genes. The density of mutations allowed mapping of putative essential domains within genes, providing a completely new level of genome annotation for any Plasmodium species. Although gene essentiality was largely conserved across P. knowlesi, Plasmodium falciparum, and rodent malaria model Plasmodium berghei, a large number of shared genes are differentially essential, revealing species-specific adaptations. Our results indicated that Plasmodium essential gene evolution was conditionally linked to adaptive rewiring of metabolic networks for different hosts.
Kidney multiome-based genetic scorecard reveals convergent coding and regulatory variants
Research Article | Nephrology | 2025-02-07 03:00 EST
Penn Medicine BioBank Daniel J. Rader, Marylyn D. Ritchie, JoEllen Weaver, Nawar Naseer, Giorgio Sirugo, Afiya Poindexter, Yi-An Ko, Kyle P. Nerz, Meghan Livingstone, Fred Vadivieso, Stephanie DerOhannessian, Teo Tran, Julia Stephanowski, Salma Santos, Ned Haubein, Joseph Dunn, Anurag Verma, Colleen Morse Kripke, Marjorie Risman, Renae Judy, Colin Wollack, Shefali S. Verma, Scott M. Damrauer, Yuki Bradford, Scott M. Dudek, Theodore G. Drivas
Kidney dysfunction is a major cause of mortality, but its genetic architecture remains elusive. In this study, we conducted a multiancestry genome-wide association study in 2.2 million individuals and identified 1026 (97 previously unknown) independent loci. Ancestry-specific analysis indicated an attenuation of newly identified signals on common variants in European ancestry populations and the power of population diversity for further discoveries. We defined genotype effects on allele-specific gene expression and regulatory circuitries in more than 700 human kidneys and 237,000 cells. We found 1363 coding variants disrupting 782 genes, with 601 genes also targeted by regulatory variants and convergence in 161 genes. Integrating 32 types of genetic information, we present the "Kidney Disease Genetic Scorecard" for prioritizing potentially causal genes, cell types, and druggable targets for kidney disease.
Nutrient-driven histone code determines exhausted CD8+ T cell fates
Research Article | Immunometabolism | 2025-02-07 03:00 EST
Shixin Ma, Michael S. Dahabieh, Thomas H. Mann, Steven Zhao, Bryan McDonald, Won-Suk Song, H. Kay Chung, Yagmur Farsakoglu, Lizmarie Garcia-Rivera, Filipe Araujo Hoffmann, Shihao Xu, Victor Y. Du, Dan Chen, Jesse Furgiuele, Michael A. LaPorta, Emily Jacobs, Lisa M. DeCamp, Brandon M. Oswald, Ryan D. Sheldon, Abigail E. Ellis, Longwei Liu, Peixiang He, Yingxiao Wang, Cholsoon Jang, Russell G. Jones, Susan M. Kaech
Exhausted T cells (TEX) in cancer and chronic viral infections undergo metabolic and epigenetic remodeling, impairing their protective capabilities. However, the impact of nutrient metabolism on epigenetic modifications that control TEX differentiation remains unclear. We showed that TEX cells shifted from acetate to citrate metabolism by down-regulating acetyl-CoA synthetase 2 (ACSS2) while maintaining ATP-citrate lyase (ACLY) activity. This metabolic switch increased citrate-dependent histone acetylation, mediated by histone acetyltransferase KAT2A-ACLY interactions, at TEX signature genes while reducing acetate-dependent histone acetylation, dependent on p300-ACSS2 complexes, at effector and memory T cell genes. Nuclear ACSS2 overexpression or ACLY inhibition prevented TEX differentiation and enhanced tumor-specific T cell responses. These findings unveiled a nutrient-instructed histone code governing CD8+ T cell differentiation, with implications for metabolic- and epigenetic-based T cell therapies.
Physical Review Letters
Quantum Origin of Limit Cycles, Fixed Points, and Critical Slowing Down
Research article | Bifurcations | 2025-02-07 05:00 EST
Shovan Dutta, Shu Zhang, and Masudul Haque
Among the most iconic features of classical dissipative dynamics are persistent limit-cycle oscillations and critical slowing down at the onset of such oscillations, where the system relaxes purely algebraically in time. On the other hand, quantum systems subject to generic Markovian dissipation decohere exponentially in time, approaching a unique steady state. Here we show how coherent limit-cycle oscillations and algebraic decay can emerge in a quantum system governed by a Markovian master equation as one approaches the classical limit, illustrating general mechanisms using a single-spin model and a two-site lossy Bose-Hubbard model. In particular, we demonstrate that the fingerprint of a limit cycle is a slow-decaying branch with vanishing decoherence rates in the Liouville spectrum, while a power-law decay is realized by a spectral collapse at the bifurcation point. We also show how these are distinct from the case of a classical fixed point, for which the quantum spectrum is gapped and can be generated from the linearized classical dynamics.
Phys. Rev. Lett. 134, 050407 (2025)
Bifurcations, Dissipative dynamics, Open quantum systems, Quantum-to-classical transition, Spin dynamics, Fokker-Planck equation, Lindblad equation, Semiclassical methods
Robust Integration of Fast Flavor Conversions in Classical Neutrino Transport
Research article | Neutrino oscillations | 2025-02-07 05:00 EST
Zewei Xiong, Meng-Ru Wu, Manu George, and Chun-Yu Lin
The quantum kinetic evolution of neutrinos in dense environments, such as the core-collapse supernovae or the neutron star mergers, can result in fast flavor conversion (FFC), presenting a significant challenge to achieving robust astrophysical modeling of these systems. Recent works that directly simulate the quantum kinetic transport of neutrinos in localized domains have suggested that the asymptotic outcome of FFCs can be modeled by simple analytical prescriptions when coarse grained over a size much larger than the FFC length scale. In this Letter, by leveraging such a scale separation, we incorporate the analytical prescriptions into global simulations that solve the classical neutrino transport equation including collisions and advection under spherical symmetry. We demonstrate that taking this approach allows to obtain results that quantitatively agree with those directly from the corresponding global quantum kinetic simulations and precisely capture the collisional feedback effect for cases where the FFC happens inside the neutrinosphere. Notably, the effective scheme does not require resolving the FFC time and length scales, hence only adds negligible computational overhead to classical transport. Our work highlights that efficient and robust integration of FFCs in classical neutrino transport used in astrophysical simulation can be feasible.
Phys. Rev. Lett. 134, 051003 (2025)
Neutrino oscillations, Novae & supernovae, Transient & explosive astronomical phenomena, Neutrinos
First Result for Dark Matter Search by WINERED
Research article | Axions | 2025-02-07 05:00 EST
Wen Yin, Taiki Bessho, Yuji Ikeda, Hitomi Kobayashi, Daisuke Taniguchi, Hiroaki Sameshima, Noriyuki Matsunaga, Shogo Otsubo, Yuki Sarugaku, Tomomi Takeuchi, Haruki Kato, Satoshi Hamano, and Hideyo Kawakita
The identity of dark matter has been a mystery in astronomy, cosmology, and particle theory for about a century. We present the first dark matter search with a high-dispersion spectrograph by using WINERED at the 6.5 m Magellan Clay telescope to measure the photons from the dark matter decays. The dwarf spheroidal galaxies (dSphs) Leo V and Tucana II are observed by utilizing an object-sky-object nodding observation technique. Employing zero consistent flux data after the sky subtraction and performing Doppler shift analysis for further background subtraction, we have established one of the most stringent limits to date on dark matter lifetime in the mass range of 1.8--2.7 eV. The conservative bound is translated to the photon coupling, \({g}_{\phi \gamma \gamma }\) for axionlike par ticles around \({g}_{\phi \gamma \gamma }\lesssim (2--3)\times{}{10}^{- 11}\text{ }\text{ }{\mathrm{GeV}}^{- 1}\) (\({10}^{- 10}\text{ }\text{ }{\mathrm{GeV}}^{- 1}\)) for the case that ultrafaint dSphs have the Navarro-Frenk-White (generalized Hernquist) dark matter profile.
Phys. Rev. Lett. 134, 051004 (2025)
Axions, Dark matter, Particle dark matter, Particle decays, Axion-like particles, Infrared spectroscopy
Refined Topology of the \(N=20\) Island of Inversion with High Precision Mass Measurements of \(^{31- 33}\mathrm{Na}\) and \(^{31- 35}\mathrm{Mg}\)
Research article | Binding energy & masses | 2025-02-07 05:00 EST
E. M. Lykiardopoulou et al.
Mass measurements of \(^{31--33}\mathrm{Na}\) and \(^{31--35}\mathrm{Mg}\) using the TITAN MR-TOF-MS at TRIUMF's ISAC facility are presented, with the uncertainty of the \(^{33}\mathrm{Na}\) mass reduced by over 2 orders of magnitude. The excellent performance of the MR-TOF-MS has also allowed the discovery of a millisecond isomer in \(^{32}\mathrm{Na}\). The precision obtained shows that the binding energy of the normally closed \(N=20\) neutron shell reaches a minimum for \(^{32}\mathrm{Mg}\) but increases significantly for \(^{31}\mathrm{Na}\), hinting at the possibility of enhanced shell strength toward the unbound \(^{28}\mathrm{O}\). We compare the results with new ab initio predictions that raise intriguing questions of nuclear structure beyond the dripline.
Phys. Rev. Lett. 134, 052503 (2025)
Binding energy & masses, Nuclear structure & decays, Shell model
Enhanced Isomer Population via Direct Irradiation of Solid-Density Targets Using a Compact Laser-Plasma Accelerator
Research article | Laser wakefield acceleration | 2025-02-07 05:00 EST
Robert E. Jacob, Speero M. Tannous, Lee A. Bernstein, Joshua Brown, Tobias Ostermayr, Qiang Chen, Dieter H G. Schneider, Carl B. Schroeder, Jeroen van Tilborg, Eric H. Esarey, and Cameron G R. Geddes
Excitation of long-lived states in bromine nuclei using a tabletop laser-plasma accelerator providing pulsed (\(<100\text{ }\text{ }\mathrm{fs}\)) electron beams provided a sensitive probe of $$ strength and level densities in the nuclear quasicontinuum and may indicate angular momentum coupling through electron-nuclear interactions. Solid-density active \({\mathrm{LaBr}}_{3}\) targets absorb real and virtual photons up to \(35\pm{}2.5\text{ }\text{ }\mathrm{MeV}\) and deexcite through $$ cascade into different states. A factor of \(4.354\pm{}0.932\) enhancement of the \(^{80}{\mathrm{Br}}^{m}{/}^{80}{\mathrm{Br}}^{g}\) isomeric ratio was observed following electron irradiation, as compared to bremsstrahlung. Additional angular momentum transfer could possibly occur through nuclear-plasma or electron-nuclear interactions enabled by the ultrashort electron beam. Further investigation of these mechanisms could have far-reaching impact including decreased storage of long-term nuclear waste and an improved understanding of heavy element formation in astrophysical settings.
Phys. Rev. Lett. 134, 052504 (2025)
Laser wakefield acceleration, Nuclear reaction rates, Nuclear reactions, Nuclear structure & decays, 59 ≤ A ≤ 89, Particle sources & targets
Interaction-Induced Topological Phase Transition at Finite Temperature
Research article | Cold gases in optical lattices | 2025-02-07 05:00 EST
Ze-Min Huang and Sebastian Diehl
The one-dimensional Su-Schrieffer-Heeger model with Hubbard interactions exhibits a defect-driven topological phase transition at finite temperatures.
Phys. Rev. Lett. 134, 053002 (2025)
Cold gases in optical lattices, Open quantum systems & decoherence, Topological phase transition, Topological phases of matter
Turbulent Spectrum of 2D Internal Gravity Waves
Research article | Kinetic theory | 2025-02-07 05:00 EST
Michal Shavit, Oliver Bühler, and Jalal Shatah
We find the turbulent energy spectrum of weakly interacting 2D internal gravity waves using the full, nonhydrostatic dispersion relation. This spectrum is an exact solution of a regularized kinetic equation, from which the zero-frequency shear modes have been excised by a careful limiting process. This is a new method in wave kinetic theory. The turbulent spectrum agrees with the 2D oceanic Garrett-Munk spectrum for frequencies large compared to the Coriolis frequency and vertical scales small compared to the depth of the ocean. We show that this turbulent spectrum is the unique power law solution to the steady kinetic equation with a nonzero radial flux. Our solution provides an interesting insight into a turbulent energy cascade in an anisotropic system---like isotropic turbulence it is self-similar in scale, but its angular part is peaked along the curve of vanishing frequency and is self-similar in frequency.
Phys. Rev. Lett. 134, 054101 (2025)
Kinetic theory, Oceanography, Stratified geophysical flows, Turbulence, Turbulent mixing
Supersolidity of Polariton Condensates in Photonic Crystal Waveguides
Research article | Exciton polariton | 2025-02-07 05:00 EST
Davide Nigro, Dimitrios Trypogeorgos, Antonio Gianfrate, Daniele Sanvitto, Iacopo Carusotto, and Dario Gerace
Prediction of a polariton supersolid state whose periodicity can be tuned by the input power, providing a novel platform to explore exotic states of matter.
Phys. Rev. Lett. 134, 056002 (2025)
Exciton polariton, Polariton condensate, Quantum fluids & solids, Supersolids
Learning Neural Free-Energy Functionals with Pair-Correlation Matching
Research article | Interface & surface thermodynamics | 2025-02-07 05:00 EST
Jacobus Dijkman, Marjolein Dijkstra, René van Roij, Max Welling, Jan-Willem van de Meent, and Bernd Ensing
The intrinsic Helmholtz free-energy functional, the centerpiece of classical density functional theory, is at best only known approximately for 3D systems. Here we introduce a method for learning a neural-network approximation of this functional by exclusively training on a dataset of radial distribution functions, circumventing the need to sample costly heterogeneous density profiles in a wide variety of external potentials. For a supercritical Lennard-Jones system with planar symmetry, we demonstrate that the learned neural free-energy functional accurately predicts inhomogeneous density profiles under various complex external potentials obtained from simulations.
Phys. Rev. Lett. 134, 056103 (2025)
Interface & surface thermodynamics, Thermal properties, Density functional theory, Machine learning
Sliding Ferroelectricity in a Bulk Misfit Layer Compound \({(\mathrm{PbS})}_{1.11}{\mathrm{VS}}_{2}\)
Research article | Ferroelectric domains | 2025-02-07 05:00 EST
Cinthia Antunes Corrêa, Jiří Volný, Kateřina Tetalová, Klára Uhlířová, Václav Petříček, Martin Vondráček, Jan Honolka, and Tim Verhagen
Twisted heterostructures of two-dimensional crystals can create a moir'e landscape, thereby changing the properties of its parent crystals. Here, the alternated stacking of posttransition metal monochalcogenides and transition metal dichalcogenides in misfit layer compound crystals is used as a moir'e generator. X-ray diffraction shows the presence of twins with a small twist angle between them. The surface electrical potential from the induced sliding ferroelectricity is seen by using scanning probe microscopy and electron microscopy with domain sizes up to tens of micrometers.
Phys. Rev. Lett. 134, 056202 (2025)
Ferroelectric domains, Ferroelectricity, 2-dimensional systems, Interfaces, Van der Waals systems
Nonresonant Electric Quantum Control of Individual On-Surface Spins
Research article | Landau-Zener effect | 2025-02-07 05:00 EST
S. A. Rodríguez, S. S. Gómez, J. Fernández-Rossier, and A. Ferrón
Quantum control techniques play an important role in manipulating and harnessing the properties of different quantum systems, including isolated atoms. Here, we propose to achieve quantum control over a single on-surface atomic spin using Landau-Zener-St"uckelberg-Majorana (LZSM) interferometry implemented with scanning tunneling microscopy (STM). Specifically, we model how the application of time-dependent, nonresonant ac electric fields across the STM tip-surface gap makes it possible to achieve precise quantum state manipulation in an isolated \({\mathrm{Fe}}^{2+}\) ion on a \(\mathrm{MgO}/\mathrm{Ag}(100)\) surface. We propose a protocol to combine Landau-Zener tunneling with LZSM interferometry that permits one to measure the quantum spin tunneling of an individual \({\mathrm{Fe}}^{2+}\) ion. The proposed experiments can be implemented with ESR-STM instrumentation, opening a new venue in the research of on-surface single spin control.
Phys. Rev. Lett. 134, 056703 (2025)
Landau-Zener effect, Quantum control, Spin dynamics, Atoms, Quantum spin models, Surfaces, Electron spin resonance scanning tunneling microscopy, Many-body techniques
Tattered Membranes and Constrained Magnets
Classical statistical mechanics | 2025-02-07 05:00 EST
Pierre Le Doussal and Leo Radzihovsky
We formulate a generalized \(D\)-dimensional field theory, parametrized by an \(O(d)\times{}O(D)\) tensor field with an energetic longitudinal constraint, describing a new class of fluctuating ''tattered'' membranes, exhibiting a nonzero density of topological connectivity defects---slits, cracks, and faults at an effective medium level. For infinite-coupling constraint, the model reproduces the elastic membrane, with its rich anomalous elasticity realized by, e.g., graphene. Two additional fixed points emerge within the critical manifold: (i) globally attractive, ''isotropic'' \(O(d)\times{}O(D)\), and (ii) ''transverse,'' which in \(D=2\) is the exact ''dual'' of the elastic membrane. Their properties are obtained in general \(D\), \(d\) from the renormalization group and the self-consistent screening analyses. They correspond to critical points of an interesting class of constrained spin models.
Phys. Rev. Lett. 134, 057101 (2025)
Classical statistical mechanics, Critical phenomena, Defects, Elasticity, Phase transitions by order
Universal Scaling Framework for Controlling Phase Behavior in Thickening and Jamming Suspensions
Research article | Jamming | 2025-02-07 05:00 EST
Meera Ramaswamy, Itay Griniasty, James P. Sethna, Bulbul Chakraborty, and Itai Cohen
Recently, we proposed a universal scaling framework that shows shear thickening in dense suspensions is governed by the crossover between two critical points: one associated with frictionless isotropic jamming and a second corresponding to frictional shear jamming. Here, we show that orthogonal perturbations to the flows, an effective method for tuning shear thickening, can also be folded into this universal scaling framework. Specifically we show that the effect of adding orthogonal shear perturbations can be incorporated into the scaling variable via a multiplicative function, determined through our measurements, to achieve collapse of the entire thickening and dethickening dataset onto a single universal curve. We then show that this universal scaling framework can be used to control the phase behavior in thickening and jamming suspensions.
Phys. Rev. Lett. 134, 058203 (2025)
Jamming, Rheology, Rheology techniques, Scaling laws of complex systems, Shear thickening
Accessing Semiaddressable Self-Assembly with Efficient Structure Enumeration
Research article | Optimization problems | 2025-02-07 05:00 EST
Maximilian C. Hübl and Carl P. Goodrich
Modern experimental methods enable the creation of self-assembly building blocks with tunable interactions, but optimally exploiting this tunability for the self-assembly of desired structures remains an important challenge. Many studies of this inverse problem start with the so-called fully addressable limit, where every particle in a target structure is different. This leads to clear design principles that often result in high assembly yield, but it is not a scalable approach---at some point, one must grapple with ''reusing'' building blocks, which lowers the degree of addressability and may cause a multitude of off-target structures to form, complicating the design process. Here, we solve a key obstacle preventing robust inverse design in the ''semiaddressable regime'' by developing a highly efficient algorithm that enumerates all structures that can be formed from a given set of building blocks. By combining this with established partition-function-based yield calculations, we show that it is almost always possible to find economical semiaddressable designs where the entropic gain from reusing building blocks outweighs the presence of off-target structures and even increases the yield of the target. Thus, not only does our enumeration algorithm enable robust and scalable inverse design in the semiaddressable regime, our results demonstrate that it is possible to operate in this regime while maintaining the level of control often associated with full addressability.
Phys. Rev. Lett. 134, 058204 (2025)
Optimization problems, Self-assembly
Surface Furrowing Instability in Everting Soft Solids
Research article | Elastic deformation | 2025-02-07 05:00 EST
Jonghyun Hwang, Mariana Altomare, and Howard A. Stone
An ultrasoft material can flow through a pipe, but the motion generates "furrows" on the material's front surface.
Phys. Rev. Lett. 134, 058205 (2025)
Elastic deformation, Pattern formation, Rheology, Surface instabilities, Gels
Physical Review X
Observation of Pattern Stabilization in a Driven Superfluid
Research article | Bose gases | 2025-02-07 05:00 EST
Nikolas Liebster, Marius Sparn, Elinor Kath, Jelte Duchene, Keisuke Fujii, Sarah L. Görlitz, Tilman Enss, Helmut Strobel, and Markus K. Oberthaler
The emergence of square lattice patterns in an otherwise round superfluid of potassium after varying the interactions of its atoms hints at a new state of driven quantum matter.
Phys. Rev. X 15, 011026 (2025)
Bose gases, Bose-Einstein condensates, Pattern formation, Spontaneous symmetry breaking
Necklacelike Pattern of Vortex Bound States
Research article | Vortices in superconductors | 2025-02-07 05:00 EST
Zhiyong Hou, Kailun Chen, Wenshan Hong, Da Wang, Wen Duan, Huan Yang, Shiliang Li, Huiqian Luo, Qiang-Hua Wang, Tao Xiang, and Hai-Hu Wen
A newly seen magnetic vortex pattern in an iron-based superconductor--neither theoretically predicted nor previously observed--could offer new insights into certain quantum phenomena in superconducting condensates.
Phys. Rev. X 15, 011027 (2025)
Vortices in superconductors, Iron-based superconductors, Superconductivity, Type-II superconductors, Unconventional superconductors, Scanning tunneling microscopy
arXiv
Topology Optimization of Pneumatic Soft Actuators Based on Porohyperelasticity
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Sumit Mehta, Konstantinos Poulios
This paper introduces a new nonlinear topology optimization framework which employs porohyperelasticity for providing computational design of pneumatic soft actuators. Density-based topology optimization is used with the objective of maximizing the bending response in a soft actuator made of an elastomer, for given actuation pressure and external resistance. Pressurization of interconnected cavities is modeled via an extension of the Darcy flow theory that is valid for large deformations. Essential for the good performance of the framework is a carefully chosen interpolation scheme for the permeability between void and solid regions, as well as a suitable definition of a drainage term in the solid regions. Results are shown for a variety of actuation pressure and maximum allowable strain energy density levels, covering a wide range of system responses from small to rather large deformations.
Soft Condensed Matter (cond-mat.soft)
26 pages, 13 figures, 1 table
Achieve equilibrium outside the contact angle hysteresis
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Lei Liu, Guanlong Guo, Kaiyu Wang, Linke Chen, Yangyang Fan, Sergio Andres Galindo Torres, Jiu-an Lv, Herbert E. Huppert, Changfu Wei, Liang Lei
It is common belief that the equilibrium contact angle, corresponding to the minimum system energy state, lies between advancing and receding contact angles. Here, we derive advancing and receding contact angles considering the micro contacting processes on ideal rough 2D surfaces. Equilibrium contact angles obtained via energy minimization can be smaller than the receding contact angle and reach 0 degrees, at which hysteresis diminishes on the super-hydrophilic surface. Gibbs free energy analyses, numerical simulations and physical experiments all confirm these new findings.
Soft Condensed Matter (cond-mat.soft)
Elasto-Hall conductivity and the anomalous Hall effect in altermagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Keigo Takahashi, Charles R. W. Steward, Masao Ogata, Rafael M. Fernandes, Jörg Schmalian
Altermagnets break time-reversal symmetry, preserve the crystal translation invariance, and have a spin density with \(d\)-wave, \(g\)-wave, etc. momentum dependencies which do not contribute to the magnetization. When an \(s\)-wave spin-density contribution cannot be excluded by symmetry a small magnetization and an anomalous Hall effect (AHE) emerge. However, for so-called "pure" altermagnets, where the \(s\)-wave component is symmetry forbidden even in the presence of SOC, both the zero-field magnetization and the AHE vanish. We show that altermagnets generally exhibit a non-zero elasto-Hall-conductivity, by which application of strain leads to a non-zero AHE. For pure altermagnets it is the only contribution to the AHE. This elasto-Hall-conductivity is caused by strain coupling to the Berry curvature quadrupole that characterizes altermagnets and allows for the determination of the altermagnetic order using transport measurements that are linear in the electrical field. We further show that the emergence of a non-zero magnetization in the presence of strain arises from a different response function: piezomagnetism. While this magnetization gives rise to an additional contribution to the elasto-Hall conductivity, the corresponding Berry curvature is qualitatively different from the distorted Berry curvature quadrupole originating from the altermagnetic order parameter. This insight also helps to disentangle AHE and weak ferromagnetism for systems with symmetry-allowed \(s\)-wave contribution. Quantitatively, the elasto-Hall conductivity is particularly pronounced for systems with a Dirac spectrum in the altermagnetic state. The same mechanism gives rise to anomalous elasto-thermal Hall, Nernst, and Ettinghausen effects.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 12 figures
Non-commutative effective field theory of the lowest Landau level superfluid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
A 2+1D superfluid in a rapidly rotating trap forms an array of vortices, with collective excitations called Tkachenko modes. Du et al. (2024) argued from an effective field theory viewpoint that these excitations are described by a field theory living on a non-commutative space. We elucidate the microscopic origin of these non-commutative fields, and present a novel derivation of the effective field theory for this superfluid using a lowest Landau level projected coherent state path integral approach. Besides conceptual clarity, this approach makes quantitative predictions about the long-wavelength, low-energy behavior in terms of the microscopic parameters of the weakly interacting lowest Landau level superfluid -- relevant to trapped Bose-Einstein condensate experiments.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas), High Energy Physics - Theory (hep-th)
10 pages + 5 pages supplementary
Realizing Quantitative Quasiparticle Modeling of Skyrmion Dynamics in Arbitrary Potentials
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-07 20:00 EST
Maarten A. Brems, Tobias Sparmann, Simon M. Fröhlich, Leonie-C. Dany, Jan Rothörl, Fabian Kammerbauer, Elizabeth M. Jefremovas, Oded Farago, Mathias Kläui, Peter Virnau
We demonstrate fully quantitative Thiele model simulations of magnetic skyrmion dynamics on previously unattainable experimentally relevant large length and time scales by ascertaining the key missing parameters needed to calibrate the experimental and simulation time scales and current-induced forces. Our work allows us to determine complete spatial pinning energy landscapes that enable quantification of experimental studies of diffusion in arbitrary potentials within the Lifson-Jackson framework. Our method enables us to ascertain the time scales, and by isolating the effect of ultra-low current density (order \(10^6 A/m^2\)) generated torques we directly infer the total force acting on the skyrmion for a quantitative modelling.
Statistical Mechanics (cond-mat.stat-mech), Materials Science (cond-mat.mtrl-sci)
Phys. Rev. Lett. 134, 046701 (2025)
Super-diffusion of Photoexcited Carriers in Topological Insulator Nanoribbons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
Rodrigo Becerra Silva, Jay Huang, Bob Minyu Wang, Ziyi Song, Henry Clark Travaglini, Dong Yu
Understanding the ultrafast dynamics and transport of photoexcited carriers in topological insulators is crucial for the optical manipulation of spins and may shed light on the nature of topological excitons. Here we investigate bulk-insulating Sb-doped \(\mathrm{Bi_2Se_3}\) nanoribbons via ultrafast transient photovoltage microscopy. The probe-pulse-induced photovoltage is substantially suppressed by a pump pulse. Recovery time increases from 50 to 1600 picoseconds as the pump fluence increases. We found that the diffusivity of photoexcited carriers increases significantly at lower carrier concentrations, up to 800 cm\(^2\)/s at 21 K, two to three orders of magnitude higher than that of band-edge carriers. Remarkably, the photoexcited carriers travel up to 10 \(\mu\)m for hundreds of picoseconds at this high diffusivity. The diffusivity peaks in intrinsic devices and is reduced at high temperatures. We discuss the possible mechanisms of long-ranged super-diffusion in the frames of hot carriers and exciton condensation.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
20 pages, 6 figures
Information-optimal mixing at low Reynolds number
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-07 20:00 EST
Luca Cocconi, Yihong Shi, Andrej Vilfan
Mutual information between particle positions before and after mixing provides a universal assumption-free measure of mixing efficiency at low Reynolds number which accounts for the kinematic reversibility of the Stokes equation. For a generic planar shear flow with time-dependent shear rate, we derive a compact expression for the mutual information as a nonlinear functional of the shearing protocol and solve the associated extremisation problem exactly to determine the optimal control under both linear and non-linear constraints, specifically total shear and total dissipation per unit volume. Remarkably, optimal protocols turn out to be universal and time-reversal symmetric in both cases. Our results establish a minimum energetic cost of erasing information through mixing.
Statistical Mechanics (cond-mat.stat-mech), Fluid Dynamics (physics.flu-dyn)
7 pages, 3 figures
Multi-Output Convolutional Neural Network for Improved Parameter Extraction in Time-Resolved Electrostatic Force Microscopy Data
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Madeleine D. Breshears, Rajiv Giridharagopal, David S. Ginger
Time-resolved scanning probe microscopy methods, like time-resolved electrostatic force microscopy (trEFM), enable imaging of dynamic processes ranging from ion motion in batteries to electronic dynamics in microstructured thin film semiconductors for solar cells. Reconstructing the underlying physical dynamics from these techniques can be challenging due to the interplay of cantilever physics with the actual transient kinetics of interest in the resulting signal. Previously, quantitative trEFM used empirical calibration of the cantilever or feed-forward neural networks trained on simulated data to extract the physical dynamics of interest. Both these approaches are limited by interpreting the underlying signal as a single exponential function, which serves as an approximation but does not adequately reflect many realistic systems. Here, we present a multi-branched, multi-output convolutional neural network (CNN) that uses the trEFM signal in addition to the physical cantilever parameters as input. The trained CNN accurately extracts parameters describing both single-exponential and bi-exponential underlying functions, and more accurately reconstructs real experimental data in the presence of noise. This work demonstrates an application of physics-informed machine learning to complex signal processing tasks, enabling more efficient and accurate analysis of trEFM.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn)
5 figures with Supporting Information attached
Universal machine learning interatomic potentials poised to supplant DFT in modeling general defects in metals and random alloys
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Fei Shuang, Zixiong Wei, Kai Liu, Wei Gao, Poulumi Dey
Recent advances in machine learning, combined with the generation of extensive density functional theory (DFT) datasets, have enabled the development of universal machine learning interatomic potentials (uMLIPs). These models offer broad applicability across the periodic table, achieving first-principles accuracy at a fraction of the computational cost of traditional DFT calculations. In this study, we demonstrate that state-of-the-art pretrained uMLIPs can effectively replace DFT for accurately modeling complex defects in a wide range of metals and alloys. Our investigation spans diverse scenarios, including grain boundaries and general defects in pure metals, defects in high-entropy alloys, hydrogen-alloy interactions, and solute-defect interactions. Remarkably, the latest EquiformerV2 models achieve DFT-level accuracy on comprehensive defect datasets, with root mean square errors (RMSE) below 5 meV/atom for energies and 100 meV/Å for forces, outperforming specialized machine learning potentials such as moment tensor potential and atomic cluster expansion. We also present a systematic analysis of accuracy versus computational cost and explore uncertainty quantification for uMLIPs. A detailed case study of tungsten (W) demonstrates that data on pure W alone is insufficient for modeling complex defects in uMLIPs, underscoring the critical importance of advanced machine learning architectures and diverse datasets, which include over 100 million structures spanning all elements. These findings establish uMLIPs as a robust alternative to DFT and a transformative tool for accelerating the discovery and design of high-performance materials.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
SymmCD: Symmetry-Preserving Crystal Generation with Diffusion Models
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Daniel Levy, Siba Smarak Panigrahi, Sékou-Oumar Kaba, Qiang Zhu, Kin Long Kelvin Lee, Mikhail Galkin, Santiago Miret, Siamak Ravanbakhsh
Generating novel crystalline materials has potential to lead to advancements in fields such as electronics, energy storage, and catalysis. The defining characteristic of crystals is their symmetry, which plays a central role in determining their physical properties. However, existing crystal generation methods either fail to generate materials that display the symmetries of real-world crystals, or simply replicate the symmetry information from examples in a database. To address this limitation, we propose SymmCD, a novel diffusion-based generative model that explicitly incorporates crystallographic symmetry into the generative process. We decompose crystals into two components and learn their joint distribution through diffusion: 1) the asymmetric unit, the smallest subset of the crystal which can generate the whole crystal through symmetry transformations, and; 2) the symmetry transformations needed to be applied to each atom in the asymmetric unit. We also use a novel and interpretable representation for these transformations, enabling generalization across different crystallographic symmetry groups. We showcase the competitive performance of SymmCD on a subset of the Materials Project, obtaining diverse and valid crystals with realistic symmetries and predicted properties.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Coexistence of 3D and quasi-2D Fermi surfaces driven by orbital selective Kondo scattering in UTe\(_2\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
Byungkyun Kang, Myoung-Hwan Kim, Chul Hong Park
The 3D Fermi surface, along with a chiral in-gap state and a Majorana zero energy state, is suggested to play a crucial role in the topologically nontrivial superconductivity in UTe\(_2\). However, conflicting experimental observations of the 2D Fermi surface raise questions about topological superconductivity. By combining ab initio many-body perturbation GW theory and dynamical mean-field theory based on Feynman diagrams, we discovered the coexistence of two orbital dependent Fermi surfaces, both centered at the \(\Gamma\) point in the Brillouin zone, which are heavily influenced by the orbital-selective Kondo effect. At high temperature, both Fermi surfaces exhibit 3D nature with weak spectral weight due to incoherent Kondo hybridization. Upon cooling down to 25 K, due to the pronounced Kondo coherence, while one Fermi surface remains a robust 3D Fermi surface, the other transforms surprisingly into a quasi-2D Fermi surface, which should be responsible for the experimental observation of 2D character. Our results suggest that the 3D Fermi surface should exist at low temperature for the topological superconductivity. Our findings call for further investigation of the interplay between the two orbital-dependent \(\Gamma\)-centered Fermi surfaces.
Strongly Correlated Electrons (cond-mat.str-el)
Polarons and Exciton-Polarons in Two-Dimensional Polar Materials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
V. Shahnazaryan, A. Kudlis, I. V. Tokatly
We propose a macroscopic theory of optical phonons, Fr{öh}lich polarons, and exciton-polarons in two-dimensional (2D) polar crystalline monolayers. Our theory extends the classical macroscopic formulation of the electron-phonon problem in three-dimensional (3D) polar crystals to the new generation of 2D materials. Similarly to the 3D case, in our approach, the effective electron-phonon Hamiltonian is parametrized solely in terms of macroscopic experimentally accessible quantities -- 2D polarizabilities of the monolayer at low and high frequencies. We derive the dispersion of long wave length longitudinal optical (LO) phonons, which can be viewed as a 2D form of the Lyddane-Sachs-Teller relation, and study the formation of 2D Fr{öh}lich polarons by adopting the intermediate coupling approximation. Finally, we apply this approach to excitons in polar 2D crystals and derive an effective potential of the electron-hole interaction dressed by LO phonons. Due to the specific dispersion of LO phonons, the polarons and exciton-polarons in 2D materials exhibit unique features not found in their 3D counterparts. As an illustration, the polaron and exciton-polaron binding energies are computed for a representative set of 2D polar crystals, demonstrating the interplay between dimensionality, polarizability of materials, and electron-phonon coupling.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Energy & Force Regression on DFT Trajectories is Not Enough for Universal Machine Learning Interatomic Potentials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Santiago Miret, Kin Long Kelvin Lee, Carmelo Gonzales, Sajid Mannan, N. M. Anoop Krishnan
Universal Machine Learning Interactomic Potentials (MLIPs) enable accelerated simulations for materials discovery. However, current research efforts fail to impactfully utilize MLIPs due to: 1. Overreliance on Density Functional Theory (DFT) for MLIP training data creation; 2. MLIPs' inability to reliably and accurately perform large-scale molecular dynamics (MD) simulations for diverse materials; 3. Limited understanding of MLIPs' underlying capabilities. To address these shortcomings, we aargue that MLIP research efforts should prioritize: 1. Employing more accurate simulation methods for large-scale MLIP training data creation (e.g. Coupled Cluster Theory) that cover a wide range of materials design spaces; 2. Creating MLIP metrology tools that leverage large-scale benchmarking, visualization, and interpretability analyses to provide a deeper understanding of MLIPs' inner workings; 3. Developing computationally efficient MLIPs to execute MD simulations that accurately model a broad set of materials properties. Together, these interdisciplinary research directions can help further the real-world application of MLIPs to accurately model complex materials at device scale.
Materials Science (cond-mat.mtrl-sci), Artificial Intelligence (cs.AI), Machine Learning (cs.LG)
Co-existing topological and Volkov-Pankratov plasmonic edge states in magnetized graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
Samyobrata Mukherjee, Viktoriia Savchuk, Jeffery W. Allen, Monica S. Allen, Gennady Shvets
Graphene placed in a perpendicular magnetic field supports optical modes known as magnetoplasmons which are transversally confined to the graphene layer. Unlike ordinary graphene plasmons, these magnetoplasmonic surface waves are characterized by a band gap corresponding to the cyclotron frequency. In addition, these magnetoplasmon bands are topological, characterized by a non-zero Chern number. This leads to the existence of topologically protected edge states at domain edges where the Chern number changes. Since the Chern number is dependent on the direction of the magnetic field, edge states exist at domain edges across which the magnetic field flips direction. Physically, the magnetic field can only flip direction at gradual domain edges with finite width creating topological heterojunctions. These topological heterojunctions support extra edge states known as Volkov-Pankratov edge states which can enter the band gap and support propagation in both directions. The number of Volkov-Pankratov states at a heterojunction varies as a function of the width of the gradual domain edge.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Microstructure-Aware Bayesian Materials Design
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Danial Khatamsaz, Vahid Attari, Raymundo Arroyave
In this study, we propose a novel microstructure-sensitive Bayesian optimization (BO) framework designed to enhance the efficiency of materials discovery by explicitly incorporating microstructural information. Traditional materials design approaches often focus exclusively on direct chemistry-process-property relationships, overlooking the critical role of microstructures. To address this limitation, our framework integrates microstructural descriptors as latent variables, enabling the construction of a comprehensive process-structure-property mapping that improves both predictive accuracy and optimization outcomes. By employing the active subspace method for dimensionality reduction, we identify the most influential microstructural features, thereby reducing computational complexity while maintaining high accuracy in the design process. This approach also enhances the probabilistic modeling capabilities of Gaussian processes, accelerating convergence to optimal material configurations with fewer iterations and experimental observations. We demonstrate the efficacy of our framework through synthetic and real-world case studies, including the design of Mg\(_2\)Sn\(_x\)Si\(_{1-x}\) thermoelectric materials for energy conversion. Our results underscore the critical role of microstructures in linking processing conditions to material properties, highlighting the potential of a microstructure-aware design paradigm to revolutionize materials discovery. Furthermore, this work suggests that since incorporating microstructure awareness improves the efficiency of Bayesian materials discovery, microstructure characterization stages should be integral to automated -- and eventually autonomous -- platforms for materials development.
Materials Science (cond-mat.mtrl-sci)
Improving noisy free-energy measurements by adding more noise
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-07 20:00 EST
Estimating free-energy differences using nonequilibrium work relations, such as the Jarzynski equality, is hindered by poor convergence when work fluctuations are large. For systems governed by overdamped Langevin dynamics, we propose the counterintuitive approach of adding noise in order to increase the precision of such calculations. By introducing additional stochastic fluctuations to the system and rescaling its potential energy, we leave the thermodynamics of the system unchanged while increasing its relaxation rate. For a given time-dependent protocol this modification reduces dissipated work, leading to more accurate free-energy estimates. We demonstrate this principle using computer simulations applied to two model systems. However, the regime of applicability of this strategy is likely limited, because it requires control of the system's potential energy in a way that is feasible in only a few experimental settings.
Statistical Mechanics (cond-mat.stat-mech)
Stacking effects on magnetic, vibrational, and optical properties of CrSBr bilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Huicong Li, Yali Yang, Zhonghao Xia, Yateng Wang, Jiacheng Wei, Jiangang He, Rongming Wang
The van der Waals layered semiconductor CrSBr, which exhibits A-type antiferromagnetism and a relatively high Néel temperature, has been successfully exfoliated into atomically thin sheets. In this study, we investigate the structural, lattice dynamical, electronic, magnetic, and optical properties of four distinct stacking structures of CrSBr bilayers using first-principles calculations and Monte Carlo simulations. Our findings show that though the most energetically favorable bilayer structure retains the stacking pattern of the bulk counterpart, three other high-symmetry stacking structures can be achieved by sliding one of the layers along three distinct directions, with energy costs comparable to that observed in MoS\(_2\) bilayer. All these four bilayers exhibit semiconductor behavior with A-type antiferromagnetic ordering, similar to the bulk material, and demonstrate closely aligned Néel temperatures. Moreover, these bilayers exhibit relatively low lattice thermal conductivities, pronounced anisotropy, and a strong dependence on stacking patterns. This behavior is attributed to significant phonon-phonon scattering arising from avoided crossings between acoustic and optical phonons, as well as the presence of flat optical phonon bands in the low-frequency region. While the electronic structures and optical properties of these bilayers show weak dependence on the stacking pattern for antiferromagnetic ordering, they undergo significant changes for ferromagnetic ordering, influencing the band gap, valence and conduction band splitting, and effective mass. Furthermore, we found that antiferromagnetic ordering can transition to ferromagnetic under intense visible light illumination. Thus, the integration of layer stacking and visible light illumination offers an effective means to control the heat transfer, magnetic, and optical properties of CrSBr bilayers.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
15 pages, 9 figures
Twist, splay, and uniform domains in ferroelectric nematic liquid crystals
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Maxim O. Lavrentovich, Priyanka Kumari, Oleg D. Lavrentovich
The recently-discovered ferroelectric nematic (\(\mathrm{N}_\mathrm{F}\)) liquid crystal presents a host of defect phenomena due to its unique polar nature and long-ranged electrostatic interactions. Like the solid state ferroelectrics, the depolarization field in the material favors a spontaneous spatial variation of the polarization \(\mathbf{P}\), manifesting in myriad ways including a twist in the bulk and different arrangements of alternating polarization domains. Unlike the solid-state ferroelectrics with a bulk crystalline structure, the configuration of the \(\mathrm{N}_\mathrm{F}\) fluids is determined not only by the reduction of depolarization fields but also by the alignment of molecules at interfaces. In this work, we consider an \(\mathrm{N}_\mathrm{F}\) confined to a thin cell, pre-patterned with various types of apolar surface anchoring produced by photoalignment. For uniform planar alignment, we find that the sample forms a series of striped domains. For a cell pre-patterned with a radial +1 defect pattern, the \(\mathrm{N}_\mathrm{F}\) breaks up into "pie-slice" polarization domains. We calculate the elastic and electrostatic energy balance which determines the observed configurations and demonstrate that the electrostatic interactions tend to decrease the characteristic domain size \(\lambda\) while the elastic and surface anchoring interactions facilitate a larger \(\lambda\). We also demonstrate that ionic screening mitigates electrostatic interactions, increasing \(\lambda\) and, above some critical concentration, eliminating the domains altogether.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
14 pages, 8 figures
Symmetry-breaking induced surface magnetization in non-magnetic RuO\(_2\)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Dai Q. Ho, D. Quang To, Ruiqi Hu, Garnett W. Bryant, Anderson Janotti
Altermagnetism is a newly identified phase of magnetism distinct from ferromagnetism and antiferromagnetism. RuO\(_2\) has been considered a prototypical metallic altermagnet with a critical temperature higher than room temperature. Previous interpretations of the unusual magnetic properties of RuO\(_2\) relied on the theoretical prediction that local moments on two Ru sublattices, which are connected by four-fold rotational symmetry, are quite significant (approximately 1 \(\mu_B\)), leading to long-range antiferromagnetic order. However, accumulated experimental data suggest that local moments on Ru in RuO\(_2\) are vanishingly small, indicating that the bulk material is likely non-magnetic. This observation is consistent with the delocalized nature of the 4\(d\) electrons of Ru and the strong screening effect in the metallic state. In this work, we show that despite the non-magnetic bulk, the RuO\(_2\)(110) surface exhibits spontaneous magnetization. We attribute this effect to the breaking of local symmetry, which results in electronic redistribution and magnetic moment enhancement. The emergence of surface magnetism gives rise to interesting spectroscopic phenomena, including spin-polarized surface states, spin-polarized scanning probe microscopy images, and potentially spin-dependent transport effects. These findings highlight the important role of surface magnetic structures in the otherwise non-magnetic bulk RuO\(_2\).
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 11 figures
A Multiscale Approach to Structural Relaxation and Diffusion in Metallic Glasses
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Anh D. Phan, Do T. Nga, Ngo T. Que, Hailong Peng, Thongchanh Norhourmour, Le M. Tu
Metallic glasses are promising materials with unique mechanical and thermal properties, but their atomic-scale dynamics remain challenging to understand. In this work, we develop a unified approach to investigate the glass transition and structural relaxation in CoCrNi, Zr46Cu46Al8, Zr50Cu40Al10, and Zr64.13Cu15.75Ni10.12Al10 metallic glasses. Molecular dynamics (MD) simulation is employed to analyze the radial distribution function at different temperatures and accurately determine the glass transition temperature. We then combine this temperature with the Elastically Collective Nonlinear Langevin Equation (ECNLE) theory to predict the temperature dependence of the structural relaxation time, tau_alpha(T). By connecting \(\tau_\alpha(T)\) to the diffusion constant, the ECNLE predictions of tau_alpha(T) can be compared with those calculated from MD simulations or estimated based on the diffusion constant. By combining atomistic simulation with force-level statistical mechanics, our multiscale approach offers deeper insights into relaxation dynamics and diffusion across various timescales. The relationship between the glass transition and the liquidus temperature is elucidated. This study enhances understanding of the glassy dynamics and properties in complex amorphous materials.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph), Computational Physics (physics.comp-ph)
7 pages, 5 figures, accepted for publication in Computational Materials Science
Out-of-phase Plasmon Excitations in the Trilayer Cuprate Bi\(_2\)Sr\(_2\)Ca\(_2\)Cu\(_3\)O\(_{10+\delta}\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
S. Nakata, M. Bejas, J. Okamoto, K. Yamamoto, D. Shiga, R. Takahashi, H. Y. Huang, H. Kumigashira, H. Wadati, J. Miyawaki, S. Ishida, H. Eisaki, A. Fujimori, A. Greco, H. Yamase, D. J. Huang, H. Suzuki
Within a homologous series of cuprate superconductors, variations in the stacking of CuO\(_2\) layers influence the collective charge dynamics through the long-range Coulomb interactions. We use O \(K\)-edge resonant inelastic x-ray scattering to reveal plasmon excitations in the optimally-doped trilayer Bi\(_2\)Sr\(_2\)Ca\(_2\)Cu\(_3\)O\(_{10+\delta}\). The observed plasmon exhibits nearly \(q_z\)-independent dispersion and a large excitation gap of approximately 300 meV. This mode is primarily ascribed to the \(\omega_{-}\) mode, where the charge density on the outer CuO\(_2\) sheets oscillates out of phase while the density in the inner sheet remains unaltered at \(q_z=0\). The intensity of the acoustic \(\omega_3\) mode is relatively weak and becomes vanishingly small near \((q_x, q_y)=(0, 0)\). This result highlights a qualitative change in the eigenmode of the dominant low-energy plasmon with the number of CuO\(_2\) layers.
Strongly Correlated Electrons (cond-mat.str-el)
Heteroepitaxial growth of highly anisotropic \(Sb_{2}Se_{3}\) films on GaAs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Kelly Xiao, Virat Tara, Pooja D. Reddy, Jarod E. Meyer, Alec M. Skipper, Rui Chen, Leland J. Nordin, Arka Majumdar, Kunal Mukherjee
The epitaxial integration of anisotropic materials with mainstream cubic semiconductors opens new routes to advanced electronic and photonic devices with directional properties. In this work, we synthesize heteroepitaxial thin films of orthorhombic "quasi-1D" \(Sb_{2}Se_{3}\) on cubic GaAs(001) using molecular beam epitaxy. Traditionally, the synthesis of anisotropic films with low symmetry materials is challenging due to multiple grain orientations that form. On a macroscopic scale, such a film tends towards isotropic properties, even if individual grains possess anisotropic responses. We achieve epitaxial \(Sb_{2}Se_{3}\) grains on pristine homoepitaxial GaAs templates at low temperatures of 180-200 °C. With the \(Sb_{2}Se_{3}\) 1D axis aligned in-plane to GaAs [110] and the primary van der Waals direction lying out-of-plane, we find a birefringence of 0.2 between in-plane orthogonal directions and a giant out-of-plane birefringence greater than 1 at telecom wavelengths. Growth at higher temperatures up to 265 °C yields \(Sb_{2}Se_{3}\) of an unusual in-plane rotated texture that further enhances the in-plane optical index anisotropy to 0.3.
Materials Science (cond-mat.mtrl-sci)
18 pages, 4 figures
Correlated helimagnetic configuration in a nonsymmorphic magnetic nodal semimetal
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
Xi Luo, Yu-Ge Chen, Ye-Min Zhan, Yue Yu
Nonsymmorphic magnetic Weyl semimetal materials such as ReAlX (Re=rare earth, X=Si/Ge) provide a unique opportunity to explore the correlated phenomena between Weyl fermions and nontrivial magnetic configurations. To be specific, we study a lattice model in which the magnetic configuration is determined by the competition among ferromagnetic (FM) interaction, the Dzyaloshinsky-Moriya interaction, and the Kondo coupling \(K_0\) to the Weyl fermion. Both quantum and finite-temperature phase transitions between FM and correlated nesting helical configurations are found. Different from the uncorrelated helimagnet that decouples to the Weyl fermions, this correlated helimagnet induces a magnetic Brillouin zone with a \(K_0\)-dependent nesting in the band structure of the conducting fermions instead of the magnetic monopole-like Weyl cone. By measuring the current induced by the chiral magnetic effect on the conducting fermion with nesting Weyl nodes, one can distinguish the correlated nesting helical order and the ferromagnetism because the chiral magnetic effect is considerably suppressed in the former case. These properties we study here may explain the experimental observations in ReAlX.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 6 figures,
Pisarenko's Formula for the Thermopower
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
The thermopower \(\alpha\) (also known as the Seebeck coefficient) is one of the most fundamental material characteristics for understanding charge carrier transport in thermoelectric materials. Here, we revisit the Pisarenko formula for the thermopower, which was traditionally considered valid only for non-degenerate semiconductors. We demonstrate that regardless of the dominating scattering mechanism, the Pisarenko formula describes accurately enough the relationship between thermopower \(\alpha\) and charge carrier concentration \(n\) beyond the non-degenerate limit. Moreover, the Pisarenko formula provides a simple thermopower-conductivity relation, \(\alpha = \pm \frac{k_{\mathrm{B}}}{e} (b - \ln \sigma)\), valid for materials with \(\alpha > 90\) \(\mu\)V K\(^{-1}\) when acoustic phonon scattering is predominant. This offers an alternative way to analyze electron transport when Hall measurements are difficult or inaccessible. Additionally, we show how the Pisarenko formula can be used to estimate the maximum power factor of a thermoelectric material from the weighted mobility of a single, not necessarily optimized, sample at any given temperature.
Materials Science (cond-mat.mtrl-sci), Physics Education (physics.ed-ph)
Dendrite Suppression in Zn Batteries Through Hetero-Epitaxial Residual Stresses Shield
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Musanna Galib, Amardeep Amardeep, Jian Liu, Mauricio Ponga
Dendrite formation is a long-standing problem for the commercial application of aqueous zinc (Zn)-ion batteries (AZIB). Here, we investigate the effect of hetero-epitaxial residual stresses due to layered coatings on dendrite suppression. We found that atomic and molecular layered coatings can substantially reduce dendritic growth in AZIB by providing shielding due to residual stresses, even at single and a few layers of coatings. Through a combined experimental and numerical approach, we demonstrate that the residual stresses developed due to the coating of the Zn anodes significantly reduced the chemical potential polarization around dendrite embryos, forcing the deposition of zinc in the regions adjacent to the protuberances. This, in turn, results in a slower rate of dendritic growth, and eventually, dendrite suppression. The fundamental understanding of the effect of residual stresses due to coatings demonstrated herein can be extended to various metal anode batteries such as Li or Na.
Materials Science (cond-mat.mtrl-sci)
Unifying shear thinning behaviors of meso-scaled particle suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Yuan Lin, Peiwen Lin, Yixuan Liang, Dingyi Pan
The rheology of suspensions with meso-scaled particles [with size of \(O(10^2)\ \text{nm}\) to \(O(10)\ \mu\text{m}\)] is intriguing since significant non-Newtonian behaviors are widely observed although the thermal fluctuation (Brownain motion) of the meso-scaled particles is negligible. Here, we show that the linear constitutive relation for such systems fails due to a flow-induced particle aggregation, which originates from the inherent inter-particle interactions, e.g., the weakly adhesive van der Waals interaction. This accounts for the temporal evolution of the rheological property in both steady and oscillatory shear flows. A dimensionless number that measures the importance of the hydrodynamic interaction in shear flow with respect to the inter-particle interaction, {is} proposed, through which the non-linear constitutive relation for suspensions with various particle sizes, particle concentrations, as well as flow conditions could be unified. This investigation bridge and make the rheology of the meso-scaled suspensions predictable.
Soft Condensed Matter (cond-mat.soft)
Oxygen sublattice disorder and valence state modulation in infinite-layer nickelate superlattices
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-07 20:00 EST
R. A. Ortiz, N. Enderlein, K. Fürsich, R. Pons, P. Radhakrishnan, E. Schierle, P. Wochner, G. Logvenov, G. Cristiani, P. Hansmann, B. Keimer, E. Benckiser
The family of infinite-layer nickelates promises important insights into the mechanism of unconventional superconductivity. Since superconductivity has so far only been observed in epitaxial thin films, heteroepitaxy with the substrate or a capping layer possibly plays an important role. Here, we use soft x-ray spectroscopy to investigate superlattices as a potential approach for a targeted material design of high-temperature superconductors. We observe modulations in valence state and oxygen coordination in topotactically reduced artificial superlattices with repeating interfaces between nickelate layers and layers of materials commonly used as substrates and capping layers. Our results show that depending on the interlayer material metallic conductivity akin to the parent infinite-layer compounds is achieved. Depth-resolved electronic structure measured by resonant x-ray reflectivity reveals a reconstructed ligand field and valence state at the interface, which is confined to one or two unit cells. The central layers show characteristics of monovalent nickel, but linear dichroism analysis reveals considerable disorder in the oxygen removal sites. We observe a quantitative correlation of this disorder with the interlayer material that is important for future modeling and design strategies.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
13 pages, 8 figures
The Role of Tunneling Oxide in the Low Frequency Noise of Multi-level Silicon Nitride ReRAMs
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Nikolaos Vasileiadis, Alexandros Mavropoulis, Christoforos Theodorou, Panagiotis Dimitrakis
This research explores the characteristics of two CMOS-compatible RRAM cells utilizing silicon nitride as the switching material. By employing SET/RESET pulse sequences, the study successfully attains four distinct and stable resistance states. To gain deeper insights, a Low-Frequency Noise (LFN) statistical analysis is conducted to investigate the role of a tunneling oxide between the bottom electrode and SiNx at various resistance levels. The findings from the LFN measurements strongly suggest that the multilevel high resistance switching primarily arises from variations in the number of nitrogen vacancies, which in turn modulate the conductivity of conductive filaments (CF). Notably, this modulation does not compromise the quality of the filament's surrounding interface. This research sheds light on the underlying mechanisms of RRAM cells and their potential for advanced memory applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Electric field tunable bands in doubly aligned bilayer graphene hBN moire superlattice
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
Priya Tiwari, Kenji Watanabe, Takashi Taniguchi, Aveek Bid
In this letter, we demonstrate electric field-induced band modification of an asymmetrically twisted hBN/BLG/hBN supermoire lattice. Distinct from unaligned BLG/hBN systems, we observe regions in the density-displacement field (n-D) plane where the device conductance is independent of n and decreases as |D| increases. This distinction arises due to the angle asymmetry between the layers, which induces field-controlled layer polarization. We identify D-dependent additional band gaps near the charge neutrality point that appear in the conduction (valence) band for negative (positive) D values. In the quantum Hall regime, new 6-fold degenerate Landau levels are observed. Our findings establish that in an asymmetric supermoire heterostructure, an external vertical displacement field affects the valence and conduction bands very differently and sheds light on the asymmetric conductance patterns noted in previous studies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phys. Rev. B 110, 235414 (2024)
Memory-induced current reversal of Brownian motors
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-07 20:00 EST
Mateusz Wiśniewski, Jakub Spiechowicz
Kinetics of biological motors such as kinesin or dynein is notably influenced by viscoelastic intracellular environment. The characteristic relaxation time of the cytosol is not separable from the colloidal timescale and therefore their dynamics is inherently non-Markovian. In this paper we consider a variant of a Brownian motor model, namely a Brownian ratchet immersed in a correlated thermal bath and analyze how memory influences its dynamics. In particular, we demonstrate the memory-induced current reversal effect and explain this phenomenon by applying the effective mass approximation as well as uncovering the memory-induced dynamical localization of the motor trajectories in the phase space. Our results reveal new aspects of the role of memory in microscopic systems out of thermal equilibrium.
Statistical Mechanics (cond-mat.stat-mech), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Soft Condensed Matter (cond-mat.soft)
in press in Phys. Rev. E
Crystal tensor properties of magnetic materials with and without spin-orbit coupling. Application of spin point groups as approximate symmetries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Jesus Etxebarria, J. Manuel Perez-Mato, Emre S. Tasci, Luis Elcoro
Spin space groups, formed by operations where the rotation of the spins is independent of the accompanying operation acting on the crystal structure, are appropriate groups to describe the symmetry of magnetic structures with null spin-orbit coupling. Their corresponding spin point groups are the symmetry groups to be considered for deriving the symmetry constraints on the form of the crystal tensor properties of such idealized structures. These groups can also be taken as approximate symmetries (with some restrictions) of real magnetic structures, where spin-orbit and magnetic anisotropy are however present. Here we formalize the invariance transformation properties that must satisfy the most important crystal tensors under a spin point group. This is done using modified Jahn symbols, which generalize those applicable to ordinary magnetic point groups [Gallego et al., Acta Cryst. (2019) A{}, 438-447]. The analysis includes not only equilibrium tensors, but also transport, optical and non-linear optical susceptibility tensors. The constraints imposed by spin collinearity and coplanarity within the spin group formalism on a series of representative tensors are discussed and compiled. As illustrative examples, the defined tensor invariance equations have been applied to some known magnetic structures, showing the differences of the symmetry-adapted form of some relevant tensors, when considered under the constraints of its spin point group or its magnetic point group. This comparison, with the spin point group implying additional constraints in the tensor form, may allow to distinguish those magnetic-related properties that can be solely attributed to spin-orbit coupling from those that are expected to be present even under negligible spin-orbit effects.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
41 pages, 7 figures
Phase diagram of the hard-sphere potential model in three and four dimensions using a pseudo-hard-sphere potential
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Edwin A. Bedolla-Montiel, Ramón A. Castañeda-Cerdán, Ramón Castañeda-Priego
The hard-sphere potential has become a cornerstone in the study of both molecular and complex fluids. Despite its mathematical simplicity, its implementation in fixed time-step molecular simulations remains a formidable challenge due to the discontinuity at contact. To circumvent the issues associated with the ill-defined force at contact, a continuous potential--referred to here as the pseudo-hard-sphere (pHS) potential--has recently been proposed [J. Chem, Phys. 149, 164907 (2018)]. This potential is constructed to match the second virial coefficient of the hard-sphere potential and is expected to mimic its thermodynamic properties. However, this hypothesis has only been partially validated within the fluid region of the phase diagram for hard-sphere dispersions in two and three dimensions. In this contribution, we examine the ability of the continuous pHS potential to reproduce the equation of state of a hard-sphere fluid, not only in the fluid phase but also across the fluid-solid coexistence region. Our focus is primarily on hard-sphere systems in three and four dimensions. We compare the results obtained from Brownian dynamics simulations of the pHS potential with those derived from refined event-driven simulations of the corresponding hard-sphere potential. Furthermore, we provide a comparative analysis with theoretical equations of state based on both mean-field and integral equation approximations.
Soft Condensed Matter (cond-mat.soft)
11 pages, 4 figures
Raman signature of multiple phase transitions and quasi-particle excitations in putative Kitaev spin liquid candidate Na2Co2TeO6
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
Atul G. Chakkar, Chaitanya B. Auti, Deepu Kumar, Nirmalya Jana, Koushik Pal, Pradeep Kumar
Two-dimensional cobalt-based honeycomb oxide Na2Co2TeO6 is an important candidate for the realization of Kitaev physics and may provide future platform for the quantum computation and quantum technology. Here, we report an in-depth temperature as well as polarization dependent inelastic light scattering (Raman) measurements on the single crystals of quasi-two-dimensional Na2Co2TeO6. Our study reveal signature of multiple phase transitions i.e. long-range zigzag antiferromagnetic transition (TN) at ~ 30 K, ferroelectric transition (TFE) at ~ 70 K, and a crossover from pure paramagnetic phase to a quantum paramagnetic phase around ~ 150 K reflected in the renormalized self-energy parameters of the Raman active phonon modes. A distinct signature of spin reorientation deep into the AFM phase around TSR ~ 17 K is observed, marked by the clear change in the frequency and linewidth slopes. We also observed an asymmetric phonon mode in the low frequency region, and it appears below the transition temperature ~ 50 K, attributed to the magnetic excitations other than the magnon. The Raman signature of multiple crystal-field excitations at low temperature along with lifting of the Kramers degeneracy is also observed. Signature of the underlying broad magnetic continuum in the quantum paramagnetic phase and its temperature dependence suggest presence of frustrated magnetic interaction in the quantum paramagnetic phase below ~ 150 K.
Strongly Correlated Electrons (cond-mat.str-el)
Triple-Q state in magnetic breathing kagome lattice
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Hangyu Zhou, Manuel dos Santos Dias, Shijian Bao, Hanchen Lu, Youguang Zhang, Weisheng Zhao, Samir Lounis
Magnetic frustration in two-dimensional spin lattices with triangular motifs underpins a series of exotic states, ranging from multi-Q configurations to disordered spin-glasses. The antiferromagnetic kagome lattice, characterized by its network of corner-sharing triangles, represents a paradigmatic frustrated system exhibiting macroscopic degeneracy. Expanding upon the kagomerization mechanism, we focus on the magnetic breathing kagome lattice formed by a Mn monolayer deposited on a heavy metal substrate and capped with h-BN. The Mn kagome arrangement induces pronounced magnetic frustration, as evidenced by the nearly flat bands derived from spin spiral energy calculations. Including further-neighbor interactions reveals a spin spiral energy minimum along the \(\Gamma\)-K line and an intriguing triple-Q state with nonzero topological charge, potentially leading to highly nonlinear Hall effects. Furthermore, the flat band properties can further give rise to an even more complex spin configuration, marked by several Q-pockets in the spin structure factor. These results present a fertile ground for advancing the study of multi-Q states and exploring emergent topological phenomena.
Materials Science (cond-mat.mtrl-sci)
27 pages, 4 figures
Photoluminescence Features of Few-Layer Hexagonal \(\alpha\)-In\(_2\)Se\(_3\)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
I.A. Eliseyev, A.I. Veretennikov, A.I. Galimov, L.V. Kotova, G.V. Osochenko, K.A. Gasnikova, D.A. Kirilenko, M.A. Yagovkina, Yu.A. Salii, V.Yu. Davydov, P.A. Alekseev, M.V. Rakhlin
Indium (III) selenide is currently one of the most actively studied materials in the two-dimensional family due to its remarkable ferroelectric and optical properties. This study focuses on the luminescent properties of few-layer In\(_2\)Se\(_3\) flakes with thicknesses ranging from 7 to 100 monolayers. To explore the photoluminescence features and correlate them with changes in crystal symmetry and surface potential, we employed a combination of techniques, including temperature-dependent micro-photoluminescence, time-resolved photoluminescence, Raman spectroscopy, atomic force microscopy, and Kelvin probe force microscopy. X-ray diffraction and Raman spectroscopy confirmed that the samples studied possess the \(\alpha\)-polytype structure. The micro-photoluminescence spectrum consists of two bands, A and B, with band B almost completely disappearing at room temperature. Temperature-dependent photoluminescence and time-resolved measurements helped us to elucidate the nature of the observed bands. We find that peak A is associated with emission from interband transitions in In\(_2\)Se\(_3\), while peak B is attributed to defect-related emission. Additionally, the photoluminescence decay times of In\(_2\)Se\(_3\) flakes with varying thicknesses were determined. No significant changes were observed in the decay components as the thickness increased from 7 to 100 monolayers, suggesting that there are no qualitative changes in the band structure.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Boosting superconductivity: how nanofaceted surfaces transform the ground state of ultrathin YBa\(_2\)Cu\(_3\)O\(_{7-\delta}\) thin films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-07 20:00 EST
E. Wahlberg, R. Arpaia, D. Chakraborty, A. Kalaboukhov, D. Vignolles, C. Proust, A. M. Black-Shaffer, G. Seibold, T. Bauch, F. Lombardi
In the cuprate high-temperature superconductors doping is fixed during synthesis and the charge carrier density per CuO\(_2\) plane cannot be easily tuned by conventional gating, unlike 2D materials. Strain engineering has recently emerged as a powerful tuning knob for manipulating the properties of cuprates, in particular charge and spin orders, and their delicate interplay with superconductivity. In thin films, additional tunability can be introduced by the substrate surface morphology, particularly nanofacets formed by substrate surface reconstruction. Here we show a remarkable enhancement of the superconducting onset temperature \(T_{\mathrm{c}}^{\mathrm{on}}\) and the upper critical magnetic field \(H_{c,2}\) in nanometer-thin YBa\(_2\)Cu\(_3\)O\(_{7-\delta}\) films grown on a substrate with a nanofaceted surface. We theoretically show that the enhancement is driven by electronic nematicity and unidirectional charge density waves, where both elements are captured by an additional effective potential at the interface between the film and the uniquely textured substrate. Our findings show a new paradigm in which substrate engineering can effectively enhance the superconducting properties of cuprates. This approach opens an exciting frontier in the design and optimization of high-performance superconducting materials.
Superconductivity (cond-mat.supr-con)
Simulation of the thermocapillary assembly of a colloidal cluster during the evaporation of a liquid film in an unevenly heated cell
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Kristina N. Kondrashova, Konstantin S. Kolegov, Irina V. Vodolazskaya
The control of the thermocapillary assembly of colloidal particle clusters is important for a variety of applications, including the creation of photonic crystals for microelectronics and optoelectronics, membrane formation for biotechnology, and surface cleaning for laboratory-on-chip devices. It is important to understand the main mechanisms that influence the formation of such clusters. This article considers a two-dimensional mathematical model describing the transfer of particles by a thermocapillary flow in an unevenly heated cell during the evaporation of a liquid. This gave us the opportunity to study one of the main processes that triggers the formation of a particle cluster. Whether the particle will move with the flow or stop at the heater, becoming the basis for the cluster, is determined by the ratio between gravity and the drag force. The results of numerical calculations show that, for small particle concentrations, their fraction entering the cluster decreases as the volumetric heat flux density \(Q\) increases. The reason for this is an increase in the thermocapillary flow with an increase in the volumetric heat flux \(Q\). It reduces the probability of particles entering the cluster.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Quantifying Ionic Liquid Affinity and Its Effect on Phospholipid Membrane Structure and Dynamics
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
V. K. Sharma, J. Gupta, H. Srinivasan, P. Hitaishi, S. K. Ghosh, S. Mitra
In this study, we examine the impact of imidazolium based ILs on the viscoelasticity, dynamics, and phase behavior of two model membrane systems, (i) lipid monolayers and (ii) unilamellar vesicles composed of dipalmitoylphosphatidylcholine (DPPC). Our findings demonstrate that both ILs induce significant disorder in lipid membranes by altering the area per lipid molecule, thereby modulating their viscoelastic properties. ILs with longer alkyl chains show stronger interactions with membranes, causing more pronounced disorder. Fourier transform infrared spectroscopy indicates that IL incorporation shifts the membrane main phase transition to lower temperatures and introduces gauche defects, signifying increased structural disorder. This effect is amplified with longer alkyl chains and higher IL concentrations. Quasielastic neutron scattering studies highlight that ILs markedly enhance the lateral diffusion of lipids within the membrane leaflet, with the extent of enhancement determined by the membrane physical state, IL concentration, and alkyl chain length. The most pronounced acceleration in lateral diffusion occurs in ordered membrane phase with higher concentrations of the longer chain IL. Molecular dynamics simulations corroborate these experimental findings, showing that longer chain ILs extensively disrupt lipid organization, introduce more gauche defects, increase the area per lipid, and consequently enhance lateral diffusion. This increase in lipid fluidity and permeability provides a mechanistic basis for the observed higher toxicity associated with longer chain ILs.
Soft Condensed Matter (cond-mat.soft)
Search for Stable States in Two-Body Excitations of the Hubbard Model on the Honeycomb Lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
Petar Sinilkov, Evan Berkowitz, Thomas Luu, Marcel Rodekamp
We present one- and two-body measurements for the Hubbard model on the honeycomb (graphene) lattice from ab-initio quantum monte carlo simulations. Of particular interest is excitons, which are particle/hole excitations in low-dimensional systems. They are analogous to the pion in QCD, but without confinement, the question of whether they are bound and stable is of great interest in the condensed matter arena. By measuring one- and two-body correlators across various spin and isospin channels we can compute two-body energies relative to their thresholds, ultimately allowing us to check for stable states.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 3 figures, 2 tables, contribution to the 41st International Symposium on Lattice Field Theory (Lattice 2024), July 28th - August 3rd, 2024, Liverpool, UK
Spontaneous helix formation in polar smectic phase
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Ewa Gorecka, Magdalena Majewska, Ladislav Fekete, Jakub Karcz, Julia Żukowska, Jakub Herman Przemysław Kula, Damian Pociecha
In soft ferroelectric crystals, the depolarization field can be reduced by periodic distortion of the polarization direction. In the polar nematic and tilted smectic phases, this process is energetically favorured , as it only requires changes in the director orientation. We demonstrate the spontaneous formation of a helical structure in the proper ferroelectric tilted smectic (SmCTBF) phase, the phase is formed below the heliconical polar nematic (NTBF) phase. The helical pitch in the smectic phase is approximately 600 nm and remains nearly constant across the entire temperature range of the phase. Under weak electric fields, the helix reorients while its structure remains largely intact; however, in stronger fields, the helix is destroyed as the electric polarization aligns along the electric field.
Soft Condensed Matter (cond-mat.soft)
Non-renormalization of the fractional quantum Hall conductivity by interactions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
M. Selch, M.A.Zubkov, Souvik Pramanik, M.Lewkowicz
We investigate the theory of the fractional quantum Hall effect (QHE) proposed a long time ago by Lopez and Fradkin . The magnetic fluxes of the statistical gauge field attached to electrons remain at rest in the reference frame moving together with the electron liquid. In the laboratory reference frame the electric field of the statistical gauge field forms and screens the external electric field. The fractional QHE conductivity appears as a consequence of this screening already on the mean field theory level. We consider a relativistic extension of the model, and propose an alternative description of the fractional QHE based on macroscopic motion of the electron liquid within the Zubarev statistical operator approach. It is this macroscopic motion of electrons which in this pattern gives rise to the fractional QHE. Within this approach we propose the proof to all orders of perturbation theory that the interaction corrections cannot change the above mentioned mean field theory result for the QHE conductivity.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Latex, 22 pages
Atomically Thin Metallenes at the Edge
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Kameyab Raza Abidi, Mohammad Bagheri, Sukhbir Singh, Pekka Koskinen
Atomically thin metallenes are a new family of materials representing the ultimate limit of a thin free-electron gas for novel applications. Although metallene research has gained traction, limited attention has been paid to the properties of their ubiquitous edges. Here, we use density-functional theory simulations to investigate various edges of Mg, Cu, Y, Au, and Pb metallenes with hexagonal and buckled honeycomb lattices. Investigating relaxations, energies, stresses, and electronic structures at the edge, we find that some properties have clear trends while others are sensitive to both element and lattice type. Given that edge properties are fundamental to metallene stability and interactions in lateral heterostructures, their detailed understanding will help guide the development of metallene synthesis and applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 6 figures
2D Mater. 12 025016 (2025)
Exploring Group Convolutional Networks for Sign Problem Mitigation via Contour Deformation
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-07 20:00 EST
Christoph Gäntgen, Thomas Luu, Marcel Rodekamp
The sign problem that arises in Hybrid Monte Carlo calculations can be mitigated by deforming the integration manifold. While simple transformations are highly efficient for simulation, their efficacy systematically decreases with decreasing temperature and increasing interaction. Machine learning models have demonstrated the ability to push further, but require additional computational effort and upfront training. While neural networks possess the capacity to learn physical symmetries through proper training, there are anticipated advantages associated with encoding them into the network's structure. These include enhanced accuracy, accelerated training, and improved stability. The objective of the present study is twofold. First, we investigate the benefits of group convolutional models in comparison to fully connected networks, with a specific focus on the effects on the sign problem and on computational aspects. Second, we examine their capabilities for transfer learning, demonstrating the ability to further reduce training cost. We perform our investigations on the Hubbard model on select low-dimensional systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Lattice (hep-lat)
Proceedings for the 41st International Symposium on Lattice Field Theory (LATTICE2024) 28 July - 3 August 2024 Liverpool, UK Accepted by Proceedings of Science
An inelastic neutron scattering study of the magnetic field dependence of the quantum dipolar garnet: Yb\(_3\)Ga\(_5\)O\(_{12}\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
Edward Riordan, Monica Ciomaga Hatnean, Geetha Balakrishnan, Kim Lefmann, Jacques Ollivier, Stephane Raymond, Elsa Lhotel, and Pascale P. Deen
The garnet compound Yb\(_3\)Ga\(_5\)O\(_{12}\) is a fascinating material that is considered highly suitable for low-temperature refrigeration, via the magnetocaloric effect, in addition to enabling the exploration of quantum states with long-range dipolar interactions. It has previously been theorized that the magnetocaloric effect can be enhanced, in Yb\(_3\)Ga\(_5\)O\(_{12}\) , via magnetic soft mode excitations which in the hyperkagome structure would be derived from an emergent magnetic structure formed from nanosized 10-spin loops. We study the magnetic field dependence of bands of magnetic soft mode excitations in the effective spin \(S = 1/2\) hyperkagome compound Yb\(_3\)Ga\(_5\)O\(_{12}\) using single crystal inelastic neutron scattering. We probe the magnetically short ranged ordered state, in which we determine magnetic nanoscale structures coexisting with a fluctuating state, and the magnetically saturated state. We determine that Yb\(_3\)Ga\(_5\)O\(_{12}\) can be described as a quantum dipolar magnet with perturbative weak near-neighbor and inter-hyperkagome exchange interaction. The magnetic excitations, under the application of a magnetic field, reveal highly robust soft modes with distinctive signatures of the quantum nature of the Yb3+ spins. Our results enhance our understanding of soft modes in topological frustrated magnets that drive both the unusual physics of quantum dipolar systems and future refrigerant material design.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Search for stable and low-energy Ce-Co-Cu ternary compounds using machine learning
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Weiyi Xia, Wei-Shen Tee, Paul Canfield, Rebecca Flint, Cai-Zhuang Wang
Cerium-based intermetallics have garnered significant research attention as potential new permanent magnets. In this study, we explore the compositional and structural landscape of Ce-Co-Cu ternary compounds using a machine learning (ML)-guided framework integrated with first-principles calculations. We employ a crystal graph convolutional neural network (CGCNN), which enables efficient screening for promising candidates, significantly accelerating the materials discovery process. With this approach, we predict five stable compounds, Ce3Co3Cu, CeCoCu2, Ce12Co7Cu, Ce11Co9Cu and Ce10Co11Cu4, with formation energies below the convex hull, along with hundreds of low-energy (possibly metastable) Ce-Co-Cu ternary compounds. First-principles calculations reveal that several structures are both energetically and dynamically stable. Notably, two Co-rich low-energy compounds, Ce4Co33Cu and Ce4Co31Cu3, are predicted to have high magnetizations.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Octagonal tilings with three prototiles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
April Lynne D. Say-awen, Sam Coates
Motivated by theoretically and experimentally observed structural phases with octagonal symmetry, we introduce a family of octagonal tilings which are composed of three prototiles. We define our tilings with respect to two non-negative integers, \(m\) and \(n\), so that the inflation factor of a given tiling is \(\delta_{(m,n)}=m+n (1+\sqrt{2})\). As such, we show that our family consists of an infinite series of tilings which can be delineated into separate `cases' which are determined by the relationship between \(m\) and \(n\). Similarly, we present the primitive substitution rules or decomposition of our prototiles, along with the statistical properties of each case, demonstrating their dependence on these integers.
Soft Condensed Matter (cond-mat.soft), Other Condensed Matter (cond-mat.other), Mathematical Physics (math-ph)
23 pages, 19 figures. Uploaded for initial community feedback before submission
Unveiling three types of fermions in a nodal ring topological semimetal through magneto-optical transitions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Jiwon Jeon, Taehyeok Kim, Jiho Jang, Hoil Kim, Mykhaylo Ozerov, Jun Sung Kim, Hongki Min, Eunjip Choi
We investigate the quasiparticles of a single nodal ring semimetal SrAs\(_3\) through axis-resolved magneto-optical measurements. We observe three types of Landau levels scaling as \(\varepsilon \sim \sqrt{B}\), \(\varepsilon \sim B^{2/3}\), and \(\varepsilon \sim B\) that correspond to Dirac, semi-Dirac, and classical fermions, respectively. Through theoretical analysis, we identify the distinct origins of these three types of fermions present within the nodal ring. In particular, semi-Dirac fermions--a novel type of fermion that can give rise to a range of unique quantum phenomena--emerge from the endpoints of the nodal ring where the energy band disperses linearly along one direction and quadratically along the perpendicular direction, a feature not achievable in nodal point or line structures. The capacity of the nodal ring to simultaneously host multiple fermion types, including semi-Dirac fermions, establishes it as a valuable platform to expand the understanding of topological semimetals.
Materials Science (cond-mat.mtrl-sci)
35 pages, 23 figures
Leading and beyond leading-order spectral form factor in chaotic quantum many-body systems across all Dyson symmetry classes
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-07 20:00 EST
Vijay Kumar, Tomaž Prosen, Dibyendu Roy
We show the emergence of random matrix theory (RMT) spectral correlations in the chaotic phase of generic periodically kicked interacting quantum many-body systems by analytically calculating spectral form factor (SFF), \(K(t)\), up to two leading orders in time, \(t\). We explicitly consider the presence or absence of time reversal (\(\mathcal{T}\)) symmetry to investigate all three Dyson's symmetry classes. Our derivation only assumes random phase approximation to enable ensemble average. For \(\mathcal{T}\)-invariant systems with \(\mathcal{T}^2=1\), we show that beyond the Thouless time \(t^\ast\), the SFF takes the form \(K(t)\simeq 2t-2t^2/\mathcal{N}\) up to second order in time, where \(\mathcal{N}\) is the Hilbert space dimension. This is identical to the result from circular orthogonal ensemble of RMT. In the absence of \(\mathcal{T}\)-symmetry, we show that \(K(t)\simeq t\) beyond \(t^\ast\), and there is no universal term in the second order, unlike the \(\mathcal{T}^2=1\) case, in agreement with the result of circular unitary ensemble. For \(\mathcal{T}\)-invariant systems with \(\mathcal{T}^2=-1\), we show that \(K(t)\simeq 2t+2t^2/\mathcal{N}\) up to two orders in time beyond \(t^\ast\), in agreement with the result of circular symplectic ensemble. In all three cases, the system-size, \(L\), scaling of \(t^\ast\) is determined by eigenvalues of a doubly stochastic matrix \(\mathcal{M}\). For strongly interacting fermionic chains, \(\mathcal{M}\) is \(SU(2)\) invariant in all three cases, leading to \(t^\ast\propto L^2\) in the presence of \(U(1)\) symmetry. In the absence of \(U(1)\) symmetry, we find \(t^\ast\propto L^0\), due to gapped non-degenerate second-largest eigenvalue of \(\mathcal{M}\) or \(t^\ast\propto \ln(L)\) due to gapped second-largest eigenvalue with degeneracy \(\propto L^\zeta\). Our calculation of SFF is plausible in higher space dimensions as well, where similar system-size scalings of \(t^\ast\) can be obtained.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Chaotic Dynamics (nlin.CD), Quantum Physics (quant-ph)
Continuously varying critical exponents in an exactly solvable long-range cluster XY mode
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
Tian-Cheng Yi, Chengxiang Ding, Maoxin Liu, Liangsheng Li, Wen-Long You
We investigate a generalized antiferromagnetic cluster XY model in a transverse magnetic field, where long-range interactions decay algebraically with distance. This model can be exactly solvable within a free fermion framework. By analyzing the gap, we explicitly derive the critical exponents \(\nu\) and \(z\), finding that the relationship \(\nu z = 1\) still holds. However, the values of \(\nu\) and \(z\) depend on the decaying exponent \(\alpha\), in contrast to those for the quantum long-range antiferromagnetic Ising chain. To optimize scaling behavior, we verify these critical exponents using correlation functions and fidelity susceptibility, achieving excellent data collapse across various system sizes by adjusting fitting parameters. Finally, we compute the entanglement entropy at the critical point to determine the central charge \(c\), and find it also varies with \(\alpha\). This study provides insights into the unique effect of long-range cluster interactions on the critical properties of quantum spin systems.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
8 pages, 7 figures
Phys. Rev. A 111, 023307 (2025)
Temperature dependent energy gap for Yu-Shiba-Rusinov states at the quantum phase transition
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-07 20:00 EST
Andreas Theiler, Christian R. Ast, Annica M. Black-Schaffer
Motivated by recent experiments, which allow for fine tuning of the effective magnetic interaction between the impurity and the superconductor, we investigate the regime around the quantum phase transition where the system's ground state changes from a weakly coupled free spin to a screened spin regime. At this transition we find that the YSR states remain at finite energies at low temperatures, thereby generating a gap in the spectrum, which is inconsistent with predictions of the original YSR theory. We investigate various gap-generating scenarios and determine that the local suppression of the order parameter, only captured by self-consistent calculations, generates the gap.
Superconductivity (cond-mat.supr-con)
15 pages, 6 figures
Pressure suppresses the density wave order in kagome metal LuNb\(_6\)Sn\(_6\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-07 20:00 EST
William R. Meier, David E. Graf, Brenden R. Ortiz, Shirin Mozaffari, David Mandrus
Dancing tins pair up, But compressing the framework Thwarts the displacements. The density waves that develop in kagome metals ScV\(_6\)Sn\(_6\) and LuNb\(_6\)Sn\(_6\) at low temperature appear to arise from under-filled atomic columns within a V-Sn or Nb-Sn scaffolding. Compressing this network with applied pressure in ScV\(_6\)Sn\(_6\) suppressed the structural transition temperature by constraining atomic rattling and inhibiting the shifts that define the structural modulation. We predicted that the density wave transition in LuNb\(_6\)Sn\(_6\) at 68 K would be suppressed by pressure as well. In this brief study we examine the pressure dependence of the density wave transition by remeasuring resistance vs temperature up to 2.26 GPa. We found the transition temperature is smoothly depressed and disappears around 1.9 GPa. This result not only addresses our prediction, but strengthens the rattling chains origin of structural instabilities in the HfFe\(_6\)Ge\(_6\)-type kagome metals.
Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 2 figures
Large Negative Magnetoresistance in off-Stochiometric Topological Material PrSbTe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Gokul Acharya, Krishna Pandey, M.M. Sharma, Jian Wang, Santosh Karki Chhetri, Md Rafique Un Nabi, Dinesh Upreti, Rabindra Basnet, Josh Sakon, Jin Hu
Magnetic topological materials LnSbTe (Ln = lanthanide) have attracted intensive attention because of the presence of interplay between magnetism, topological, and electron correlations depending on the choices of magnetic Ln elements. Varying Sb and Te composition is an efficient approach to control structural, magnetic, and electronic properties. Here we report the composition-dependent properties in PrSbxTe2-x. We identified the tetragonal-to-orthorhombic structure transitions in this material system, and very large negative magnetoresistance in the x = 0.3 composition, which might be ascribed to the coupling between magnetism and transport. Such unusual magnetotransport enables PrSbxTe2-x topological materials as a promising platform for device applications.
Materials Science (cond-mat.mtrl-sci)
24 pages, 6 figures, 1 table
Phys. Rev. B 111, 024421 (2025)
Phonon spectra, quantum geometry, and the Goldstone theorem
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
Guglielmo Pellitteri, Guido Menichetti, Andrea Tomadin, Haoyu Hu, Yi Jiang, B. Andrei Bernevig, Marco Polini
Phonons are essential (quasi)particles of all crystals and play a key role in fundamental properties such as thermal transport and superconductivity. In particular, acoustic phonons can be viewed as the Goldstone modes arising from the spontaneous breaking of translational symmetry. In this article, we present a comprehensive - in the absence of Holstein phonons - theory of the quantum geometric contributions to the phonon spectra of crystals. Using graphene as a case study, we separate the dynamical matrix into several terms that depend differently on the electron energy and wavefunction, and demonstrate that the quantum geometric effects are crucial in shaping the phonon spectra of the material. Neglecting them leads to a gap in the acoustic phonon branches, which clearly violates the Goldstone theorem.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
9 pages, 3 figures + extensive Supplemental Material (13 pages, 3 figures). Comments are welcome!
Josephson coupling in Lanthanum-based cuprates superlattices
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-07 20:00 EST
Halima Giovanna Ahmad, Davide Massarotti, Francesco Tafuri, Gennady Logvenov, Antonio Bianconi, Gaetano Campi
In most anisotropic compounds such as bismuth-based layered cuprate perovskites, the supercurrent across the blocking layer is of Josephson type, and a single crystal forms a natural stack of Josephson junctions. Here, we report on the evidence of Josephson-like transport in an artificial cuprate superlattice composed of 10 LaSrCuO-LaCuO repeats, creating a superlattice of junctions, where LCO is a superconducting Mott insulator and LSCO an overdoped metal, respectively. The superlattice has been designed with a long period d = L+W = 5.28 nm, with L and W the thickness of LCO and LSCO units, respectively, and is in the underdoped regime with an average doping level < {} >= 0.11. Quantum-size effects and Rashba spin-orbit coupling are controlled by L/d = 0.75, with a quasi-2D superconducting transition temperature of 41 K and a c-axis coherence length of about 1.5 nm. Measurements at very low temperatures show evidence of Josephson phase dynamics consistent with very low Josephson coupling and a phase diffusion regime, thus explaining why Josephson coupling in LSCO superlattices has been so elusive. The tuning of LSCO superlattices in the Josephson regime enriches the phase diagram of HTS.
Superconductivity (cond-mat.supr-con)
APL Quantum 1 March 2025; 2 (1): 016113
Anderson insulator-based cryogenic photonic thermal amplifiers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
Matteo Pioldi, Giorgio De Simoni, Alessandro Braggio, Francesco Giazotto
A photonic heat amplifier (PHA) designed for cryogenic operations is introduced and analyzed. This device comprises two Anderson insulator reservoirs connected by lossless lines, allowing them to exchange heat through photonic modes. This configuration enables negative differential thermal conductance (NDTC), which can be harnessed to amplify thermal signals. To achieve this, we maintain one reservoir at a high temperature, serving as the source terminal of a thermal transistor. Concurrently, in the other one, we establish tunnel contacts to metallic reservoirs, which function as the gate and drain terminals. With this arrangement, it is possible to control the heat flux exchange between the source and drain by adjusting the gate temperature. We present two distinct parameter choices that yield different performances: the first emphasizes modulating the source-drain heat current, while the second focuses on the temperature modulation of the colder Anderson insulator. Lastly, we present a potential design variation in which all electronic reservoirs are thermally connected through only photonic modes, allowing interactions between distant elements. The proposal of the PHA addresses the lack of thermal transistors and amplifiers in the mK range while being compatible with the rich toolbox of circuit quantum electrodynamics. It can be adapted to various applications, including sensing and developing thermal circuits and control devices at sub-Kelvin temperatures, which are relevant to quantum technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 6 figures
The effect of Carrier Doping and Thickness on the Electronic Structures of La\(3\)Ni\(2\)O\(7\) Thin Films
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-07 20:00 EST
Haoliang Shi, Zihao Huo, Guanlin Li, Hao Ma, Tian Cui, Dao-Xin Yao, Defang Duan
Recently, the superconductivity of bilayer nickelate La3Ni2O7 has been observed in the thin film at ambient pressure, facilitated by epitaxial strain. Here, we investigate the effects of film thickness and carrier doping on the electronic structure of La3Ni2O7 thin films with thickness of 0.5-3 unit cells (UC) using first-principles calculations. At an optimal doping concentration of 0.4 holes per formula unit for 2UC film, the Ni-"d" _("z" ^"2" ) interlayer bonding state metallizes, leading to the formation of {} pockets at the Fermi surface, which quantitatively matches the experimental results of angle-resolved photoemission spectroscopy (ARPES). These findings provide theoretical support for recent experimental observations of ambient-pressure superconductivity in La3Ni2O7 thin films and highlight the crucial role of film thickness and carrier doping in modulating electronic properties.
Superconductivity (cond-mat.supr-con)
12 pages, 4 figures
Isolating the hard core of phaseless inference: the Phase selection formulation
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-07 20:00 EST
Davide Straziota, Luca Saglietti
Real-valued Phase retrieval is a non-convex continuous inference problem, where a high-dimensional signal is to be reconstructed from a dataset of signless linear measurements. Focusing on the noiseless case, we aim to disentangle the two distinct sub-tasks entailed in the Phase retrieval problem: the hard combinatorial problem of retrieving the missing signs of the measurements, and the nested convex problem of regressing the input-output observations to recover the hidden signal. To this end, we introduce and analytically characterize a two-level formulation of the problem, called ``Phase selection''. Within the Replica Theory framework, we perform a large deviation analysis to characterize the minimum mean squared error achievable with different guesses for the hidden signs. Moreover, we study the free-energy landscape of the problem when both levels are optimized simultaneously, as a function of the dataset size. At low temperatures, in proximity to the Bayes-optimal threshold -- previously derived in the context of Phase retrieval -- we detect the coexistence of two free-energy branches, one connected to the random initialization condition and a second to the signal. We derive the phase diagram for a first-order transition after which the two branches merge. Interestingly, introducing an \(L_2\) regularization in the regression sub-task can anticipate the transition to lower dataset sizes, at the cost of a bias in the signal reconstructions which can be removed by annealing the regularization intensity. Finally, we study the inference performance of three meta-heuristics in the context of Phase selection: Simulated Annealing, Approximate Message Passing, and Langevin Dynamics on the continuous relaxation of the sign variables. With simultaneous annealing of the temperature and the \(L_2\) regularization, they are shown to approach the Bayes-optimal sample efficiency.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
Mutual Multilinearity of Nonequilibrium Network Currents
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-07 20:00 EST
Sara Dal Cengio, Pedro E. Harunari, Vivien Lecomte, Matteo Polettini
Continuous-time Markov chains have been successful in modelling systems across numerous fields, with currents being fundamental entities that describe the flows of energy, particles, individuals, chemical species, information, or other quantities. They apply to systems described by agents transitioning between vertices along the edges of a network (at some rate in each direction). It has recently been shown by the authors that, at stationarity, a hidden linearity exists between currents that flow along edges: if one controls the current of a specific "input" edge (by tuning transition rates along it), any other current is a linear-affine function of the input current [PRL 133, 047401 (2024)]. In this paper, we extend this result to the situation where one controls the currents of several edges, and prove that other currents are in linear-affine relation with the input ones. Two proofs with distinct insights are provided: the first relies on Kirchhoff's current law and reduces the input set inductively through graph analysis, while the second utilizes the resolvent approach via a Laplace transform in time. We obtain explicit expressions for the current-to-current susceptibilities, which allow one to map current dependencies through the network. We also verify from our expression that Kirchhoff's current law is recovered as a limiting case of our mutual linearity. Last, we uncover that susceptibilities can be obtained from fluctuations when the reference system is originally at equilibrium.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph)
24 pages, 4 figures
Site-engineered ferromagnetism in Ca and Cr co-substituted Bismuth Ferrite Nanoparticles
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-07 20:00 EST
Mehedi Hasan Prince, Abrar Daiyan, Troyee Mitra Aishi, Anika Rahman Riya, Md. Fakhrul Islam, Md. Abdullah Zubair, Takian Fakhrul
Multiferroic perovskites that exhibit room temperature magnetization and polarization have immense potential in the next generation of magneto-electric and spintronic memory devices. In this work, the magnetic and ferroelectric properties of Bismuth Ferrite, BiFeO3 (BFO) nanoparticles (NPs) were enhanced through simultaneous A and B site Ca and Cr co-substitution. Novel compositions of Bi0.97Ca0.03CrxFe1-xO3 (x=0, 0.01, 0.03, 0.05) were synthesized using the sol-gel route and annealed at 550 degrees Celcius. Rietveld Refinement of XRD patterns confirmed high phase purity, while SEM analysis revealed a decreasing trend in average particle size with increasing dopant concentration. Hysteresis loops showed enhanced magnetic properties as particle size approached the spin cycloid wavelength (around 62 nm), disrupting the intrinsic antiferromagnetic ordering of BFO. Moreover, the presence of exchange bias in the NPs was linked to the formation of core-shell structure. Temperature dependent magnetization studies showed an increase in Néel temperature upon Ca substitution. XPS analysis confirmed that Bi0.97Ca0.03FeO3 samples exhibited the highest oxygen vacancy concentration, while Fe3+ remained the dominant oxidation state across all compositions. Ferroelectric polarization loop measurements showed enhanced remanent polarization in doped samples, with leakage linked to oxygen vacancies and extrinsic microstructural effects.
Materials Science (cond-mat.mtrl-sci)
Mehedi Hasan Prince, Abrar Daiyan, Troyee Mitra Aishi contributed equally to this work. Paper undergoing review in Ceramics International
Shape-asymmetry and flexibility in active cross-stream migration in nonuniform shear
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-07 20:00 EST
Derek C. Gomes, Tapan C. Adhyapak
We show that the interplay of activity and broken fore-aft symmetry of shapes helps microswimmers to migrate across streamlines in nonuniform shear, emphasizing a hitherto overlooked fundamental cause of active cross-stream migration in imposed flows. Using a framework on model flagellated microswimmers in a microchannel flow, we find that besides the broken head-tail shape symmetry, extended hydrodynamic coupling is vital for cross-stream migration, whereas flagellar flexibility significantly affects the same. Furthermore, by simplifying the problem to a basic analytical model, we are able to identify the fundamental factors affecting the observed rich nonlinear dynamics and predict the sorting and control of microswimmer populations inside a microchannel. Our predictions are general and apply to both living and artificial microswimmers, whereas the hydrodynamic framework developed here is necessary to probe other scenarios, such as in dense suspensions, where non-uniform shear and near-field flows become important.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Non-unitary time dynamics of topological modes in open planar quantum systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-07 20:00 EST
Nontrivial topological invariant of bulk electronic wavefunctions in two-dimensional quantum crystals leaves its footprints on the edge, dislocation, and corner modes. Here we investigate non-unitary time dynamics of these topological modes in square lattice-based open quantum systems in which the time-dependent Hamiltonian smoothly interpolates between topologically distinct insulators across band gap closing quantum critical points. The temporal dynamics of these modes is described by a Lindblad equation in which the instantaneous Hamiltonian plays the role of the Lindblad operator, thereby allowing the environment to couple with the system through the energy channels (weak measurement protocol). We show that in the presence of such a real time ramp, the survival probability of these modes decreases (increases) in short (long) time scale where the dephasing (quantum Zeno) effect dominates with the increasing amplitude of the system-to-environment coupling, for both slow and fast ramps from a topological to a normal insulating state. For a reverse course of the time evolution, the revival or condensation probability of nucleating such topological modes, otherwise absent in the initial system, increases for stronger system-to-environment coupling. This phenomenon can be attributed to the strong decoherence of the initial mixed state among all the energy eigenstates of the final Hamiltonian which also includes the topological modes, causing their enhanced condensation probability. Our findings can be germane to real open topological materials with time-tunable band gap, and should be applicable to open topological crystals of arbitrary dimension and belonging to any symmetry class.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
18 Pages, 17 Figures