CMP Journal 2025-02-25
Statistics
Nature Physics: 1
Physical Review Letters: 4
Physical Review X: 2
arXiv: 104
Nature Physics
Topological interactions drive the first fate decision in the Drosophila embryo
Original Paper | Biological physics | 2025-02-24 19:00 EST
Woonyung Hur, Arghyadip Mukherjee, Luke Hayden, Ziqi Lu, Anna Chao, Noah P. Mitchell, Sebastian J. Streichan, Massimo Vergassola, Stefano Di Talia
During embryogenesis, the first cell fate decision--whether the cell participates in development of the embryo or not--is often linked to the positioning of the nucleus. The cell cycle oscillator and associated cytoskeletal dynamics contribute to the control of nuclear positioning. However, the mechanisms that ensure that the correct number of nuclei move to their appropriate place remain poorly understood. Here we show that the orientation of the mitotic spindle controls the first fate decision, embryonic or yolk cell fate, in Drosophila embryos using light sheet microscopy experiments. Combining computational methods inspired by integral geometry, manipulation of cell cycle genes, and investigation of the relationship between geometry and topology, we show that spindle orientation is controlled by topological interactions with neighbouring nuclei and not by internuclear distance. Leveraging the physics of space-filling systems, we develop a theory for topological dependency in microtubule structures. Our work shows how the topological interplay of microtubule mechanics can ensure robust control of nuclear density and determine cell fate.
Biological physics, Computational biophysics
Physical Review Letters
Essay: Mapping Luminous and Dark Matter in the Universe
Essay | Dark matter | 2025-02-25 05:00 EST
Nora Elisa Chisari
In a new forward-looking Essay, Dr. Nora Elisa Chisari explores various strategies that will assist scientists by offering a comprehensive view of how luminous matter is clustered in the Universe across cosmic time and highlights some of the intriguing open questions that these studies will address in the coming decades.
Phys. Rev. Lett. 134, 080001 (2025)
Dark matter, Evolution of the Universe, Sky surveys, Baryons, Astrophysical & cosmological simulations
Single versus the Repetitive Penrose Process in a Kerr Black Hole
Research article | Classical black holes | 2025-02-25 05:00 EST
Remo Ruffini, Mikalai Prakapenia, Hernando Quevedo, and Shurui Zhang
Extracting the rotational energy from a Kerr black hole (BH) is one of the crucial topics in relativistic astrophysics. Here, we give special attention to the Penrose ballistic process based on the fission of a massive particle \({\mu }_{0}\) into two particles \({\mu }_{1}\) and \({\mu }_{2}\), occurring in the ergosphere of a Kerr BH. Bardeen et al. indicated that for the process to occur, some additional ''hydrodynamical forces or superstrong radiation reactions'' were needed. Wald and Chandrasekhar further expanded this idea. This animosity convinced Piran and collaborators to move from a simple three-body system characterizing the original Penrose process to a many-body system. This many-body approach was further largely expanded by others, some questionable in their validity. Here, we return to the simplest original Penrose process and show that the solution of the equations of motion, imposing the turning point condition on their trajectories, leads to the rotational energy extraction from the BH expected by Penrose. The efficiency of energy extraction by a single process is quantified for three different single decay processes occurring, respectively, at \(r=1.2M\), \(r=1.5M\), and \(r=1.9M\). An interesting repetitive model has been proposed by Misner et al. [Gravitation (W. H. Freeman, San Francisco, 1973)]. Indeed, it would appear that a repetitive sequence of 246 decays of the above injection process at \(r=1.2M\) and the corresponding ones at \(r=1.5M\) and \(r=1.9M\) could extract 100% of the rotational energy of the BH, so violating energy conservation. The accompanying article, accounting for the existence of the BH irreducible mass, introduces a nonlinear approach that avoids violating energy conservation and leads to a new energy extraction process.
Phys. Rev. Lett. 134, 081403 (2025)
Classical black holes
Kolmogorov Scaling in Turbulent 2D Bose-Einstein Condensates
Research article | Turbulence | 2025-02-25 05:00 EST
M. Zhao, J. Tao, and I. B. Spielman
Researchers showed that a turbulent Bose-Einstein condensate exhibits the signs of classical turbulence, hinting at possible similarities between classical and quantum fluids.
Phys. Rev. Lett. 134, 083402 (2025)
Turbulence, Bose-Einstein condensates, Superfluids, Particle image velocimetry, Velocimetry
Formation of Iron-Helium Compounds under High Pressure
Research article | Magnetism | 2025-02-25 05:00 EST
Haruki Takezawa, Han Hsu, Kei Hirose, Fumiya Sakai, Suyu Fu, Hitoshi Gomi, Shiro Miwa, and Naoya Sakamoto
Experiments show that iron's crystal lattice expands to incorporate helium.
Phys. Rev. Lett. 134, 084101 (2025)
Magnetism, Phase diagrams, Phase transitions, Pressure effects, Structural properties
Physical Review X
Dispersive Dark Excitons in van der Waals Ferromagnet \({\mathrm{CrI}}_{3}\)
Research article | Magnetism | 2025-02-25 05:00 EST
W. He, J. Sears, F. Barantani, T. Kim, J. W. Villanova, T. Berlijn, M. Lajer, M. A. McGuire, J. Pelliciari, V. Bisogni, S. Johnston, E. Baldini, M. Mitrano, and M. P. M. Dean
Resonant inelastic x-ray scattering reveals elusive "dark excitons" in CrI3. With long lifetimes and unique spin interactions, these controllable quasiparticles offer novel prospects for quantum technologies and optoelectronic devices.
Phys. Rev. X 15, 011042 (2025)
Magnetism, Layered crystals, Exact diagonalization, Resonant inelastic x-ray scattering
Mechanical Tuning of Residual Stress, Memory, and Aging in Soft Glassy Materials
Research article | Aging | 2025-02-25 05:00 EST
Paolo Edera, Minaspi Bantawa, Stefano Aime, Roger T. Bonnecaze, and Michel Cloitre
Pasty materials store mechanical memory through local stress distributions. By periodically shearing them, their memory can be controlled or erased, offering insights for optimizing materials in coatings, composites, and consumer products.
Phys. Rev. X 15, 011043 (2025)
Aging, Jamming, Plastic deformation, Rheology, Smart materials, Colloidal glass, Glassy systems, Microgels, Soft colloids, Annealing, Molecular dynamics, Rheology techniques
arXiv
Structural and mechanical characterisation of nylon fibre aggregates
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
L. Gey, R. Guenin, P. Le Gal, G. Verhille
The study of fibre networks is of great importance due to their appearance in a wide range of natural and industrial processes. These networks are particularly complex because their properties depend not only on the characteristics of individual fibres but also on their collective arrangements within the network. In this study, we investigate the case of nylon fibre aggregates that were generated in a turbulent von Karman flow. The key properties of these aggregates are characterized, including their three-dimensional structures, analysed through X-ray tomography, and their mechanical responses. The results are compared with those observed for aegagropilae, a natural fibre aggregate commonly found on the Mediterranean sea shore
Soft Condensed Matter (cond-mat.soft)
17 pages, 8 figures
Statistical density of particles in one dimensional interaction and Jellium Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-25 20:00 EST
We study a one-dimensional gas of \(n\) charged particles confined by a potential and interacting through the Riesz potential or a more general potential. In equilibrium, and for symmetric potential the particles arrange themselves symmetrically around the origin within a finite region. Various models will be studied by modifying both the confining potential and the interaction potential. Focusing on the statistical properties of the system, we analyze the position of the rightmost particle, \(x_{\text{max}}\), and show that its typical fluctuations are described by a limiting distribution different from the Tracy-Widom distribution found in the one-dimensional log-gas. We also derive the large deviation functions governing the atypical fluctuations of \(x_{\text{max}}\) far from its mean.
Statistical Mechanics (cond-mat.stat-mech), Mathematical Physics (math-ph), Probability (math.PR)
Hartree-Fock approximation for bosons with symmetry-adapted variational wave functions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-25 20:00 EST
B. R. Que, J. M. Zhang, H. F. Song, Y. Liu
The Hartree-Fock approximation for bosons employs variational wave functions that are a combination of permanents. These are bosonic counterpart of the fermionic Slater determinants, but with the significant distinction that the single-particle orbitals used to construct a permanent can be arbitrary and do not need to be orthogonal to each other. Typically, the variational wave function may break the symmetry of the Hamiltonian, resulting in qualitative and quantitative errors in physical observables. A straightforward method to restore symmetry is projection after variation, where we project the variational wave function onto the desired symmetry sector. However, a more effective strategy is variation after projection, which involves first creating a symmetry-adapted variational wave function and then optimizing its parameters. We have devised a scheme to realize this strategy and have tested it on various models with symmetry groups ranging from \(\mathbb{Z}_2\), \(\text{C}_L\), to \(\text{D}_L\). In all the models and symmetry sectors studied, the variational wave function accurately estimates not only the energy of the lowest eigenstate but also the single-particle correlation function, as it approximate the target eigenstate very well on the wave function level. We have applied this method to study few-body bound states, superfluid fraction, and Yrast lines of some Bose-Hubbard models. This approach should be valuable for studying few-body or mesoscopic bosonic systems.
Quantum Gases (cond-mat.quant-gas)
22 pages, 12 figures
Electrostatics in semiconducting devices I : The Pure Electrostatics Self Consistent Approximation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
A. Lacerda-Santos, Xavier Waintal
In quantum nanoelectronics devices, the electrostatic energy is the largest energy scale at play and, to a large extend, it determines the charge distribution inside the devices. Here, we introduce the Pure Electrostatic Self consistent Approximation (PESCA) that provides a minimum model that describes how to include a semiconductor in an electrostatic calculation to properly account for both screening and partial depletion due to e.g. field effect. We show how PESCA may be used to reconstruct the charge distribution from the measurement of pinch-off phase diagrams in the gate voltages space. PESCA can also be extended to account for magnetic field and calculate the edge reconstruction in the quantum Hall regime. The validity of PESCA is controlled by a small parameter \(\kappa = C_g/C_q\), the ratio of the geometrical capacitance to the quantum capacitance, which is, in many common situations, of the order of 1%, making PESCA a quantitative technique for the calculation of the charge distribution inside devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages. 13 figures. 2 tables
Photo-assisted shot noise probes multiple charge carriers in quantum Hall edges
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Kishore Iyer, Flavio Ronetti, Benoît Grémaud, Thierry Martin, Thibaut Jonckheere, Jérôme Rech
Fractional charges in the fractional quantum Hall effect were first observed via DC shot noise measurements of anyons tunneling at a quantum point contact (QPC). However, in scenarios with simultaneous tunneling of different types of charges at the QPC, the connection between DC shot noise and tunneling charge is less transparent. Photo-assisted shot noise (PASN), induced by periodic AC voltage, offers a promising alternative. Here, we investigate PASN in the hierarchical states of the fractional quantum Hall effect, where different types of charges are expected to tunnel concurrently at QPCs. In the particular case of the fractional quantum Hall state \(\nu = 2/3\), our analysis demonstrates that PASN can be employed as a robust tool to detect different tunneling charges, even when the tunneling amplitude of one type is significantly smaller compared to the other. We show that the features predicted by our calculations are still visible for typical values of temperature and frequency achieved in state-of-the-art experiments. Our general formalism can be used to compute PASN for general Abelian quantum Hall systems with multiple edge modes and charge types.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Nonvolatile Electric Control of Antiferromagnet CrSBr
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Junhyeon Jo, Samuel Mañas-Valero, Eugenio Coronado, Fèlix Casanova, Marco Gobbi, Luis E. Hueso
van der Waals magnets are emerging as a promising material platform for electric field control of magnetism, offering a pathway towards the elimination of external magnetic fields from spintronic devices. A further step is the integration of such magnets with electrical gating components which would enable nonvolatile control of magnetic states. However, this approach remains unexplored for antiferromagnets, despite their growing significance in spintronics. Here, we demonstrate nonvolatile electric field control of magnetoelectric characteristics in van der Waals antiferromagnet CrSBr. We integrate a CrSBr channel in a flash-memory architecture featuring charge trapping graphene multilayers. The electrical gate operation triggers a nonvolatile 200 % change in the antiferromagnetic state of CrSBr resistance by manipulating electron accumulation/depletion. Moreover, the nonvolatile gate modulates the metamagnetic transition field of CrSBr and the magnitude of magnetoresistance. Our findings highlight the potential of manipulating magnetic properties of antiferromagnetic semiconductors in a nonvolatile way.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Nano Letters 24, 15, 4471 (2024)
Topological Computation by non-Abelian Braiding in Classical Metamaterials
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Liyuan Chen, Matthew Fuertes, Bolei Deng
We propose a realization of the one-dimensional Kitaev topological superconductor in classical mechanical metamaterials. By designing appropriate braiding protocols, we demonstrate that the system's mid-gap vibrational modes, termed classical Majorana zero modes (MZMs), accurately reproduce the braiding statistics predicted by quantum theory. Encoding four MZMs as a classical analog of a qubit, we implement all single-qubit Clifford gates through braiding, enabling the simulation of topological quantum computation in a classical system. Furthermore, we establish the system's topological protection by demonstrating its robustness against mechanical defects. This work provides a novel framework for exploring topological quantum computation using classical metamaterials and offers a pathway to realizing stable vibrational systems protected by topology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Quantum Physics (quant-ph)
14 pages, 9 figures
Proximity-Induced Nodal Metal in an Extremely Underdoped CuO\(_2\) Plane in Triple-Layer Cuprates
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Shin-ichiro Ideta, Shintaro Adachi, Takashi Noji, Shunpei Yamaguchi, Nae Sasaki, Shigeyuki Ishida, Shin-ichi Uchida, Takenori Fujii, Takao Watanabe, Wen O. Wang, Brian Moritz, Thomas P. Devereaux, Masashi Arita, Chung-Yu Mou, Teppei Yoshida, Kiyohisa Tanaka, Ting-Kuo Lee, Atsushi Fujimori
ARPES studies have established that the high-\(T_c\) cuprates with single and double CuO\(_2\) layers evolve from the Mott insulator to the pseudogap state with a Fermi arc, on which the superconducting (SC) gap opens. In four- to six-layer cuprates, on the other hand, small hole Fermi pockets are formed in the innermost CuO\(_2\) planes, indicating antiferromagnetism. Here, we performed ARPES studies on the triple-layer Bi\(_2\)Sr\(_2\)Ca\(_2\)Cu\(_3\)O\(_{10+\delta}\) over a wide doping range, and found that, although the doping level of the inner CuO\(_2\) plane was extremely low in underdoped samples, the \(d\)-wave SC gap was enhanced to the unprecedentedly large value of $_0$100 meV at the antinode and persisted well above \(T_{c}\) without the appearance of a Fermi arc, indicating a robust ``nodal metal''. We attribute the nodal metallic behavior to the unique local environment of the inner clean CuO\(_2\) plane in the triple-layer cuprates, sandwiched by nearly optimally-doped two outer CuO\(_2\) planes and hence subject to strong proximity effect from both sides. In the nodal metal, quasiparticle peaks showed electron-hole symmetry, suggesting \(d\)-wave pairing fluctuations. Thus the proximity effect on the innermost CuO\({_2}\) plane is the strongest in the triple-layer cuprates, which explains why the \(T_c\) reaches the maximum at the layer number of three in every multi-layer cuprate family.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Tunable magnon band topology and magnon orbital Nernst effect in noncollinear antiferromagnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
D. Quang To, Dai Q. Ho, Joshua M. O. Zide, Lars Gundlach, M. Benjamin Jungfleisch, Garnett W. Bryant, Anderson Janotti, Matthew F. Doty
We theoretically investigate the intrinsic magnon orbital Nernst effect (ONE) in noncollinear antiferromagnets with Kagomé spin systems. Our analysis reveals that an externally applied magnetic field induces topological phase transitions in the magnonic system, characterized by the closing and reopening of the band gap between distinct magnon bands. These transitions enable tunable control of the magnon orbital Nernst effect with applied magnetic field, with a pronounced enhancement in magnon orbital Nernst conductivity near the phase transition points. This tunability presents a promising direction for experimental detection of the magnon ONE.
Materials Science (cond-mat.mtrl-sci)
11 pages, 6 figures
Site-selective observation of spin dynamics of a Tomonaga-Luttinger liquid in frustrated Heisenberg chains
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Diep Minh Nguyen, Azimjon A. Temurjonov, Daigorou Hirai, Zenji Hiroi, Oleg Janson, Hiroshi Yasuoka, Taku Matsushita, Yoshiaki Kobayashi, Yasuhiro Shimizu
Low-energy spin dynamics is investigated by \(^{35}\) Cl NMR measurements in a frustrated antiferromagnet Ca\(_3\)ReO\(_5\)Cl\(_2\). The local spin susceptibility measured with the Knight shift behaves as a one-dimensional Heisenberg antiferromagnet and remains constant down to low temperatures, as expected in a gapless Tomonaga-Luttinger liquid. The nuclear spin-lattice relaxation rate \(T_1^{-1}\) demonstrates a slowing down of atomic motions and a power-law evolution of spin correlation. The Luttinger parameter is enhanced in a site-selective manner depending on the form factor of dynamical spin susceptibility. The strong anisotropy of \(T_1^{-1}\) reflects the strong spin-orbit coupling through Dzyaloshinskii-Moriya interaction. The ground state exhibits an incommensurate antiferromagnetic ordering with low-lying magnon excitations.
Strongly Correlated Electrons (cond-mat.str-el)
11 pages, 9 figures
Physical Review B 111, 064423 (2025)
\(d\)-Wave Polarization-Spin Locking in Two-Dimensional Altermagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
We report the emergence of an uncharted phenomenon, termed \(d\)-wave polarization-spin locking (PSL), in two-dimensional (2D) altermagnets. This phenomenon arises from nontrivial Berry connections, resulting in perpendicular electronic polarizations in the spin-up and spin-down channels. Symmetry-protected \(d\)-wave PSL occurs exclusively in \(d\)-wave altermagnets with tetragonal layer groups. To identify 2D altermagnets capable of exhibiting this phenomenon, we propose a symmetry-eigenvalue-based criterion, and a rapid method by observing the spin-momentum locking. Using first-principles calculations, monolayer Cr\(_2\)X\(_2\)O (X = Se, Te) characterizes promising candidates for \(d\)-wave PSL, driven by the unusual charge order in these monolayers. This unique polarization-spin interplay leads to spin-up and spin-down electrons accumulating at orthogonal edges, enabling potential applications as spin filters or splitters in spintronics. Furthermore, \(d\)-wave PSL introduces an unexpected spin-driven ferroelectricity in conventional antiferromagnets. Such magnetoelectric coupling positions \(d\)-wave PSL as an ideal platform for fast antiferromagnetic memory devices. Our findings not only expand the landscape of altermagnets, complementing conventional collinear ferromagnets and antiferromagnets, but also highlight tantalizing functionalities in altermagnetic materials, potentially revolutionizing information technology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
11 Pages, 4 figures
Effect of Particle Shape on Stratification in Drying Films of Binary Colloidal Mixtures
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Binghan Liu, Gary S. Grest, Shengfeng Cheng
The role of particle shape in evaporation-induced auto-stratification in dispersed colloidal suspensions is explored with molecular dynamics simulations of mixtures of solid spheres, aspherical particles, and hollow spheres. A unified framework is proposed for the stratification phenomena in systems that feature size or shape dispersity on the basis of two processes: diffusion and diffusiophoresis. In general, diffusion favors the accumulation of particles that diffuse more slowly at the evaporation front. However, particles with larger surface areas have larger diffusiophoretic mobilities and are more likely to be driven away from the evaporation front by the concentration gradients of other particles with smaller surface areas. In the case of a bidisperse colloidal suspension containing small and large solid spheres studied in most of the work reported in the literature, the competition between the two leads to the so-called "small-on-top" stratification when the suspension is rapidly dried, as diffusiophoresis dominates near the interface. Here we employ a computational model of composite particles that mimics the Rouse model of polymers, where the diffusion coefficient of a particle is inversely proportional to its mass. For a mixture of solid spheres and aspherical particles or hollow spheres with similar masses, the diffusion contrast is reduced and the solid spheres are always enriched at the evaporation front, as they have the smallest surface area for a given mass and therefore the lowest diffusiophoretic mobility. The unified framework is further corroborated with a case study of a mixture of solid and hollow spheres having the same outer radius and thus the same surface area. In this case, the diffusiophoretic contrast is suppressed and the solid spheres, which have a larger mass and thus a smaller diffusion coefficient, are found to accumulate at the evaporation front.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
20 pages, 6 figures, including Supplementary Information
The surface binding and energy issues in rational design of the separation membrane of Li||S batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Shuyu Cheng, Lijing Wang Chao Wu, Sheng Yang, Yang Liu, Yi Zhao, Dandan Cui, Shaowei Zhang, Shixue Dou, Hongfang Du, Liangxu Lin
Lithium-sulfur batteries (LSBs) represent one of the most promising next-generation energy storage technologies, offering exceptionally high energy densities. However, their widespread adoption remains hindered by challenges such as sluggish conversion reactions and the dissolution of lithium polysulfides, which lead to poor cycling stability and reduced performance. While significant efforts have been made to address these limitations, the energy storage capabilities of LSBs in practical devices remain far from achieving their full potential. This report delves into recent advancements in the rational design of separation membranes for LSBs, focusing on addressing fundamental issues related to surface binding and surface energy interactions within materials science. By examining the functionalization and optimization of separation membranes, we aim to highlight strategies that can guide the development of more robust and efficient LSBs, bringing them closer to practical implementation.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
40 pages, 9 figures
Valley resolved dynamics of phonon bottleneck in semiconductor molybdenum ditelluride
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Zhong Wang, Yijie Shi, Yu Pan, Min Li, Xi Wang, Zheng Zhang, Xiangyu Zhu, Fuyong Hua, Qian You, Chunlong Hu, Junjie He, Yu Ye, Wenxi Liang
Semiconductor molybdenum ditelluride (2H-MoTe2) possess multiple valleys in the band structure, enriching its physical properties and potentials in applications. The understanding of its multivalley nature of fundamental processes involving population and relaxation of carriers and phonons is still evolving; particularly, the possible phonon bottleneck has not yet been addressed. Here, we investigate the carrier intra- and intervalley scattering and the phonon dynamics in different valleys in photoexcited few-layer 2H-MoTe2, by using the time resolved measurements of optical absorption and electron diffraction, together with the density functional theory calculation and molecular dynamics simulation. The pathways and timescales of carrier relaxation, accompanied with the emissions of optical phonons at the Brillouin zone center and acoustic phonons at the zone border are revealed. We present a couple of approaches to estimate the population of different phonon modes based on the results of optical and electron diffraction measurements, hence quantitatively identify the occurrences of phonon bottleneck located in different valleys. Our findings make possible to construct a comprehensive picture of the complex interactions between carriers and phonons in 2H-MoTe2 with the valley degree of freedom resolved.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
34 pages, 17 figures (including Supplementary Information)
Klein Tunneling and Fabry-Pérot Resonances in Twisted Bilayer Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Ayoub Bahlaoui, Youness Zahidi
The paper discusses the Klein tunneling and Fabry-Pérot resonances of charge carriers through a rectangular potential barrier in twisted bilayer graphene. Within the framework of the low-energy excitations, the transmission probability and the conductance are obtained depending on the parameters of the problem. Owing to the different chirality in twisted bilayer graphene, the propagation of charge carriers exhibits an anisotropic behavior in transmission probability and Fabry-Pérot resonances. Moreover, we show that the anisotropy of the charge carriers induces asymmetry and deflection in the Fabry-Pérot resonances and Klein tunneling, and they are extremely sensitive to the height of the potential applied. Additionally, we found that the conductance is strongly sensitive to the barrier height but weakly sensitive to the barrier width. Therefore, it is possible to control the maxima and minima of the conductance of charge carriers in twisted bilayer graphene. With our results, we gain an in-depth understanding of tunneling properties in twisted bilayer graphene, which may help in the development and designing of novel electronic nanodevices based on anisotropic 2D materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 8 figures
Multistate Control of Nonlinear Photocurrents in Optoferroelectrics via phase manipulation of light field
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Ali Kazempour, Esmaeil Taghizadeh Sisakht, Mahmut Sait Okyay, Xiao Jiang, Shunsuke Sato, Noejung Park
Ultrafast optical control of ferroelectricity based on short and intense light can be utilized to achieve accurate manipulations of ferroelectric materials, which may pave a basis for future breakthrough in nonvolatile memories. Here, we demonstrate that phase manipulation of electric field in the strong field sub-cycle regime induces a nonlinear injection current, efficiently coupling with the topology of band structure and enabling dynamic reversal of both current and polarization. Our time-dependent first-principles calculations reveal that tuning the phase of linearly or circularly polarized light through time-varying chirp, or constant carrier envelop phases within sub-laser-cycle dynamics effectively breaks the time-reversal symmetry, allowing the control over current and electronic polarization reversal over multi-ferroelectric states. Our time- and momentum-resolved transverse current analysis reveal the significance of Berry curvature higher order poles in the apparent association between the odd (even) orders of Berry curvature multipoles to odd (even) pseudo-harmonics in driving polarization dynamics reversal. We suggest that these phase manipulations of short pulse waveform may lead to unprecedented accurate control of nonlinear photocurrents and polarization states, which facilitate the development of precise ultrafast opto-ferroelectric devices.
Materials Science (cond-mat.mtrl-sci)
Stabilized biskyrmion states in annealed CoFeB bilayer with different interfaces
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
W. Al Saidi, S. Amara, M. T. Zar Myint, S. Al Harthi, G. Setti, R. Sbiaa
This study investigates the stability of skyrmions and biskyrmions in perpendicular magnetic tunneling junctions with a thick CoFeB/Ta/CoFeB free layer. The samples showed a magnetoresistance of ~ 41% when annealed at 230 °C. Magnetic force microscopy revealed the existence of skyrmions and biskyrmions at room temperature in the as-deposited state and under an external magnetic field. Annealing at 330 °C enhanced interfacial Dzyaloshinskii-Moriya interaction (DMI) and crystallinity, enabling the spontaneous coexistence of these topological structures. Micromagnetic simulations using MuMax3 explored the interplay between DMI strength, sign, and skyrmion chirality. Skyrmions exhibited repulsive interactions, while biskyrmions displayed attractive interactions due to the difference in helicities. The study highlights the influence of multilayer structure and varying Ta layer thicknesses on the DMI charility, which modulates the formation of complex spin textures. These results provide an understanding of skyrmion and biskyrmion dynamics and their potential for spintronic applications, including racetrack memory and data storage technologies.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Harnessing Nonlinearity to Tame Wave Dynamics in Nonreciprocal Active Systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Sayan Jana, Bertin Many Manda, Vassos Achilleos, Dimitrios J. Frantzeskakis, Lea Sirota
We present a mechanism to generate unidirectional pulse-shaped propagating waves, tamed to exponential growth and dispersion, in active systems with nonreciprocal and nonlinear couplings. In particular, when all bulk modes are exponentially localized at one side of the lattice (skin effect), it is expected that wave dynamics is governed by amplification or decay until reaching the boundaries, even in the presence of dissipation. Our analytical results, and experimental demonstrations in an active electrical transmission line metamaterial, reveal that nonlinearity is a crucial tuning parameter in mediating a delicate interplay between nonreciprocity, dispersion, and dissipation. Consequently, undistorted unidirectional solitonic pulses are supported both for low and high nonreciprocity and pulse amplitude strength. The proposed mechanism facilitates robust pulse propagation in signal processing and energy transmission applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Multi-component altermagnet: A general approach to generating multi-component structures with two-dimensional altermagnetism
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Hongjie Peng, Sike Zeng, Ji-Hai Liao, Chang-Chun He, Xiao-Bao Yang, Yu-Jun Zhao
Altermagnetism, as an unconventional antiferromagnetism, exhibits collinear-compensated magnetic order in real space and spin-splitting band structure in reciprocal space. In this work, we propose a general approach to generating multi-component structures with two-dimensional altermagnetism, based on symmetry analysis. Specifically, by analyzing the space group of the crystal structures and their subgroups, we systematically categorize equivalent atomic positions and arrange them into orbits based on symmetry operations. Chemical elements are then allowed to occupy all atomic positions on these orbits, generating candidate structures with specific symmetries. We present a general technique for generating collinear-compensated magnetic order, characterized by the symmetrical interconnection between opposite-spin sublattices, and employ first-principles calculations to determine magnetic ground states of multi-component materials. This approach integrates symmetry analysis with the screening of altermagnetic configurations to evaluate the likelihood of candidates possessing altermagnetism. To verify the methodology, we provide examples of previously unreported 2D altermagnets, such as Cr2Si2S3Se3, Fe2P2S3Se3, and V2O2BrI3, and evaluate their dynamical stability by calculating the phonon spectrum. The results demonstrate the feasibility of our approach in generating stable multi-component structures with two-dimensional altermagnetism. Our research has significantly enriched the candidate materials for 2D altermagnet and provided a reference for experimental synthesis.
Materials Science (cond-mat.mtrl-sci)
Scaling of many-body localization transitions: Quantum dynamics in Fock space and real space
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-25 20:00 EST
Thibault Scoquart, Igor V. Gornyi, Alexander D. Mirlin
Many-body-localization (MBL) transitions are studied in a family of single-spin-flip spin-\(\frac12\) models, including the one-dimensional (1D) chain with nearest-neighbor interactions, the quantum dot (QD) model with all-to-all pair interactions, and the quantum random energy model (QREM). We investigate the generalized imbalance that characterizes propagation in Fock space out of an initial basis state and, at the same time, can be efficiently probed by real-space measurements. For all models considered, the average imbalance and its quantum and mesoscopic fluctuations provide excellent indicators for the position of the MBL transition \(W_c(n)\), where \(n\) is the number of spins. Combining these findings with earlier results on level statistics, we determine phase diagrams of the MBL transitions in the \(n\)-\(W\) plane. Our results provide evidence for a direct transition between the ergodic and MBL phases for each of the models, without any intermediate phase. For QREM and QD model, \(W_c(n)\) grows as a power law of \(n\) (with logarithmic corrections), in agreement with analytical predictions \(W_c^{\rm QREM}(n) \sim n^{1/2} \ln n\) and \(W_c^{\rm QD}(n) \gtrsim n^{3/4} \ln^{1/2} n\). This growth is in stark contrast to the 1D model, where \(W_c(n)\) is essentially independent of \(n\), consistent with the analytic expectation \(W_c^{\rm 1D}(n\to \infty)= {\rm const}\). We also determine the scaling of the transition width \(\Delta W (n) / W_c(n)\) and estimate the system size \(n\) needed to study the asymptotic scaling behavior. While these values of \(n\) are not accessible to exact simulations on a classical computer, they are within the reach of quantum simulators. Our results indicate feasibility of experimental studies of \(n\)-\(W\) phase diagrams and scaling properties of MBL transitions in models of 1D and QD type and in their extensions to other spatial geometry or distance-dependent interactions.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
33 pages, 14 figures
Accelerating Combinatorial Electrocatalyst Discovery with Bayesian Optimization: A Case Study in the Quaternary System Ni-Pd-Pt-Ru for the Oxygen Evolution Reaction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
F. Thelen, R. Zehl, R. Zerdoumi, J. L. Bürgel, L. Banko, W. Schuhmann, A. Ludwig
The discovery of high-performance electrocatalysts is crucial for advancing sustainable energy technologies. Compositionally complex solid solutions comprising multiple metals offer promising catalytic properties, yet their exploration is challenging due to the combinatorial explosion of possible compositions. In this work, we combine combinatorial sputtering of thin-film materials libraries and their high-throughput characterization with Bayesian optimization to efficiently explore the quaternary composition space Ni-Pd-Pt-Ru for the oxygen evolution reaction in alkaline media. Using this method, the global activity optimum of pure Ru was identified after covering less than 20% of the complete composition space with six materials libraries. Six additional libraries were fabricated to validate the activity trend. The resulting dataset is used to formulate general guidelines for the efficient composition space exploration using combinatorial synthesis paired with Bayesian optimization.
Materials Science (cond-mat.mtrl-sci)
Geometric origin of supercurrents in Berry phase: Formula for computing currents from wavefunctions with correlation and particle number variation
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-25 20:00 EST
B. Q. Song, J. D. H. Smith, J. Wang
The complexity of itinerant and many-body nature in Bardeen-Cooper-Schrieffer (BCS) wavefunctions has traditionally led to the use of coarse-grained order parameters for describing currents in superconductors (SC), rather than directly utilizing wavefunctions. In this work, we introduce a phase-based formula that enables the direct computation of currents from microscopic wavefunctions, accounting for correlation and particle number variations. Interestingly, the formulation draws parallels with insulators, suggesting a unified framework for understanding (intra-band) charge transport across two extremes of conductivity. A group velocity current \(J_{band}{\propto}\frac{1}{\hbar}{\partial}_kE(k)\) is derived from Berry phase, independent of wave package dynamics, robust against correlation. Additionally, we identify a correlation-driven contribution, \(J_{corr}\), which reveals that the pairing correlations \({\langle}c_kc_{-k}{\rangle}\) among dancing partners provide a current component beyond the velocity operator.
Superconductivity (cond-mat.supr-con)
8 pages, 2 figures
Polarization of photoluminescence by optically driven orbital reconstruction in magnetically ordered CrCl3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Lanqing Zhou, Marjana Ležaić, Yuriy Mokrousov, Minh N. Bui, Renu Rani, Detlev Grützmacher, Beata E. Kardynał
In this paper, we show that photoluminescence from CrCl3 bulk crystal exhibits a preferential polarization direction when films are magnetically ordered or strained. We verify the magnetization as responsible for the polarization by measuring the signal as a function of the temperature in Voigt configuration while applying the in-plane magnetic field. We show that phonon coupling contributing to vibronic transitions depolarizes the signal compared with zero phonon lines. We explain the data using DFT calculations, which reveal a magnetization-selective occupation of the low energy d-orbital triplet state of Cr3+ upon photon absorption. In addition, the calculations find that the excitation of one electron results in the excited state acquiring out-of-plane components of spin and very large orbital magnetic moments, in addition to a lattice deformation.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
21 pages, 12 figures
Sampling through Algorithmic Diffusion in non-convex Perceptron problems
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-25 20:00 EST
Elizaveta Demyanenko, Davide Straziota, Carlo Baldassi, Carlo Lucibello
We analyze the problem of sampling from the solution space of simple yet non-convex neural network models by employing a denoising diffusion process known as Algorithmic Stochastic Localization, where the score function is provided by Approximate Message Passing. We introduce a formalism based on the replica method to characterize the process in the infinite-size limit in terms of a few order parameters, and, in particular, we provide criteria for the feasibility of sampling. We show that, in the case of the spherical perceptron problem with negative stability, approximate uniform sampling is achievable across the entire replica symmetric region of the phase diagram. In contrast, for the binary perceptron, uniform sampling via diffusion invariably fails due to the overlap gap property exhibited by the typical set of solutions. We discuss the first steps in defining alternative measures that can be efficiently sampled.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Machine Learning (cs.LG)
A comprehensive study of out-of-equilibrium Kondo effect and Coulomb blockade
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Matthieu Jeannin, Yuriel Núñez-Fernández, Thomas Kloss, Olivier Parcollet, Xavier Waintal
We present a comprehensive set of numerically exact results for the Anderson model of a quantum dot coupled to two electrodes in non-equilibrium regime. We use a high order perturbative expansion in power of the interaction \(U\), coupled to a cross-extrapolation method to long time and large interaction. The perturbative series is computed up to \(20-25\) orders, using tensor cross-interpolation. We calculate the full Coulomb diamond bias voltage - gate voltage map, including its Kondo ridge, that forms the standard experimental signature of the Coulomb blockage and the Kondo effect. We present current-voltage characteristics that spans three orders of magnitude in bias voltage and display five different regimes of interest from probing the Kondo resonance at small bias to saturation at very high bias. Our technique also naturally produces time-resolved interaction quenches which we use to study the dynamics of the formation of the Kondo cloud. Finally, we predict several qualitatively new physical features that should be within reach of existing or upcoming experiments.
Strongly Correlated Electrons (cond-mat.str-el)
Realization of discretized response in rare-earth vanadates accessed by AC susceptibility and magnetocaloric methods
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Yuntian Li, Linda Ye, Mark P. Zic, Matthias S. Ikeda, Arkady Shekhter, Ian R. Fisher
This report presents a new technique to probe the quantitative dynamical response of the magnetic field induced heating/cooling process in rare-earth vanadium materials. The approach combines AC susceptibility and AC caloric measurements to reveal the intrinsic timescale associated with the magnetic relaxation process of rare-earth ions at low temperatures. Utilizing the well-known crystal field effect in YbVO4, we prove and demonstrate a discretized thermal analysis through a common spin-lattice relaxation phenomenon. The demonstration experiment presented in this study provides a general approach to quantitatively address multiple measured quantities in one unified discretized thermal circuit analysis. It can be extended to study other magnetic, dielectric, and elastic materials exhibiting a complex response to an external driving field in the presence of intrinsic interactions and fluctuations, particularly when an energy dissipation process is within an accessible frequency regime.
Materials Science (cond-mat.mtrl-sci), Data Analysis, Statistics and Probability (physics.data-an), Instrumentation and Detectors (physics.ins-det)
Observation of spin splitting in the surface electronic structure of antiferromagnet NdBi
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Rikako Yamamoto, Takeru Motoyama, Takuma Iwata, Towa Kosa, Yukimi Nishioka, Kazumasa Ideura, Masashi Arita, Koji Miyamoto, Taichi Okuda, Akio Kimura, Takemi Yamada, Yuki Yanagi, Takahiro Onimaru, Kenta Kuroda
Spin splitting in electronic band structures via antiferromagnetic orders is a new route to control spin-polarized carriers that is available for spintronics applications. Here, we investigated the spin degree of freedom in the electronic band structures of the antiferromagnet NdBi using laser-based spin- and angle-resolved photoemission spectroscopy (laser-SARPES). Our laser-SARPES experiments revealed that the two surface bands that appear in the antiferromagnetic state are spin-polarized in opposite directions as a counterpart of the spin splitting. Moreover, we observed that the spin polarization is antisymmetric to the electron momentum, indicating that spin degeneracy is lifted due the breaking of inversion symmetry at the surface. These results are well reproduced by our density functional theory calculations with the single-q magnetic structure, implying that the spin-split surface state is determined by the breaking of inversion symmetry in concert with the antiferromagnetic order.
Materials Science (cond-mat.mtrl-sci)
Skyrmion Crystal in a Microwave Field
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
D. A. Garanin, E. M. Chudnovsky
Temperature and field dependences of the frequencies of uniform modes of the skyrmion lattice in a 2D ferromagnetic film with Dzyaloshinskii-Moriya interaction, as well as their damping, are computed within the model of classical spins. We show that the magnetization of the film exhibits Rabi-like oscillations when subjected to the microwave field at resonance with the low-frequency mode. Melting of the skyrmion lattice by resonant microwaves is investigated in terms of the time dependence of the orientational and translational order parameters. A distinct single-stage melting transition has been observed.
Materials Science (cond-mat.mtrl-sci)
14 pages in Phys. Rev. format, 12 figure captions, 17 figure panels
Full-film dry transfer of MBE-grown van der Waals materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Ziling Li, Wenyi Zhou, Matthew Swann, Vika Vorona, Haley Scott, Roland K. Kawakami
Molecular beam epitaxy (MBE) has been used to create high-quality, large-scale two-dimensional van der Waals (2D vdW) materials. However, due to the strong adhesion between the substrate and deposited materials, the peel-off and dry transfer of MBE-grown vdW films onto other substrates has been challenging. This limits the study and use of MBE films for heterogeneous integration including stacked and twisted heterostructures. In this work, we develop a polymer-assisted dry transfer method and successfully perform full-film transfer of various MBE-grown 2D vdW materials including transition metal dichalcogenides (TMD), topological insulators (TI) and 2D magnets. In particular, we transfer air-sensitive 2D magnets, characterize their magnetic properties, and compare them with as-grown materials. The results show that the transfer technique does not degrade the magnetic properties, with the Curie temperature and hysteresis loops exhibiting similar behaviors after the transfer. Our results enable further development of heterogeneous integration of 2D vdW materials based on MBE growth.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
6 pages, 4 figures
Topological descriptors for the electron density of inorganic solids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Nathan J. Szymanski, Alexander Smith, Prodromos Daoutidis, Christopher J. Bartel
Descriptors play an important role in data-driven approaches for materials design. While most descriptors of inorganic crystalline materials emphasize structure and composition, they often neglect the electron density - a complex yet fundamental quantity that governs material properties. In this work, we introduce Betti curves as topological descriptors that compress the electron density into compact representations. Derived from persistent homology, Betti curves capture bonding characteristics by encoding components, cycles, and voids across varied electron density thresholds. Machine learning models trained on Betti curves outperform those trained on raw electron densities by an average of 33 percentage points in classifying structure prototypes, predicting thermodynamic stability, and distinguishing metals from non-metals. Shannon entropy calculations reveal that Betti curves retain comparable information content to electron density while requiring two orders of magnitude less data. By combining expressive power with compact representation, Betti curves highlight the potential of topological data analysis to advance the modeling and design of inorganic materials.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Charge-state dependent spin-orbit coupling and quantum phase transitions in Ir-Ru oxides
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Kuldeep Kargeti, Bidyut Mallick, Vladislav Borisov, Sk. Soyeb Ali, Johan Hellsvik, Olle Eriksson, S. K. Panda
The competition between kinematic, relativistic and Coulombic interactions in iridium-based oxides has spurred intense experimental and theoretical investigations regarding the electronic structure and magnetism. We argue here that the Iridium-Ruthenium triple perovskites, Ba\(_3\)MRuIrO\(_9\) (M = Li, Mg and In), are of particular interest in this regard. We show here, using ab-initio theory, that the nominal charge states of Ir can be tuned from +6 to +4 by choosing non-magnetic 'M' ions as Li (+1), Mg(+2) and In (+3). This variation modulates the influence of the spin-orbit coupling (SOC) which is found here to be negligible in Ba\(_3\)LiRuIrO\(_9\), moderate in Ba\(_3\)MgRuIrO\(_9\) and determining in Ba\(_3\)InRuIrO\(_9\). Our analysis classifies Ba\(_3\)LiRuIrO\(_9\) as a band-insulator, Ba\(_3\)MgRuIrO\(_9\) as a SOC and correlation driven insulator and Ba\(_3\)InRuIrO\(_9\) as \(J_{\rm eff} = 1/2\) Mott-Hubbard insulator. As reported here, correlated electronic structure theory results in sizeable magnetic moments of both Ru and Ir atoms in these systems and atomistic spin-dynamics simulations capture the experimental Néel temperature for Ba\(_3\)LiRuIrO\(_9\) and Ba\(_3\)MgRuIrO\(_9\) and provide evidence for a phase transition for Ba\(_3\)InRuIrO\(_9\) when T \(\to\) 0 K, to a multi-valley magnetic state with strong magnetic frustration. The theory identifies the presence of Kitaev interaction among the iridium atoms in Ba\(_3\)InRuIrO\(_9\). The realization of such strong anisotropic interactions helps to stabilize a particularly complex energy landscape of Ba\(_3\)InRuIrO\(_9\), that opens up for exotic magnetic quantum phases.
Strongly Correlated Electrons (cond-mat.str-el)
Perfect spin-triplet pairing in two-dimensional Ising superconductors purified by indirect excitons
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-25 20:00 EST
Chuanyi Zhang, Yu Li, Ping Cui, Zhenyu Zhang
Much research effort has been devoted to interfacial or two-dimensional (2D) superconductors, but the underlying pairing mechanisms and pairing symmetries are highly controversial in most cases. Here we propose an innovative approach to probe the pairing symmetry of 2D superconductors, based on a van der Waals heterostructure consisting of a prototypical 2D Ising superconductor coupled with a 2D hole gas through an insulating spacer. We first show that, by tuning the Coulomb attraction between the superconducting and hole layers, the gap of the corresponding indirect exciton insulators is tuned as well, resulting in contrasting manifestations of the distinct superconducting channels with spin-singlet (s-, extended s-, and d-wave) and spin-triplet (p- and f-wave) pairings. Strikingly, we find that the application of in-plane magnetic fields can suppress all other channels while selecting the spin-triplet p-wave channel to be the pure superconducting state, thus providing an ideal and practical platform for realizing highly desirable topological superconductivity. Such an approach can also be readily extended to other types of superconducting systems, offering unprecedented opportunities to probe the microscopic mechanisms of unconventional superconductivity.
Superconductivity (cond-mat.supr-con)
Main text and Supplementary Information, peer review
Inversion-asymmetric itinerant antiferromagnets by the space group symmetry
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
We investigate the appearance of an inversion-asymmetric antiferromagnetism due to an itinerant mechanism in nonsymmorphic systems with magnetic ions at Wyckoff position of multiplicity 2. The key symmetries which underpin the existence of such phases are established, and we derive a Landau free energy from a general microscopic electronic Hamiltonian. Our analysis reveals that the stable antiferromagnetic order is largely determined by the symmetries of Wyckoff position, the nature of the nesting between electronic bands, and the presence of anisotropy or nesting in high-symmetry planes of the Brillouin zone. We illustrate our conclusions with specific microscopic models.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 pages, 3 figures, Appendix 10 pages
Correlated Dephasing in a Piezoelectrically Transduced Silicon Phononic Waveguide
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Oliver A. Hitchcock, Felix M. Mayor, Wentao Jiang, Matthew P. Maksymowych, Sultan Malik, Amir H. Safavi-Naeini
Nanomechanical waveguides offer a multitude of applications in quantum and classical technologies. Here, we design, fabricate, and characterize a compact silicon single-mode phononic waveguide actuated by a thin-film lithium niobate piezoelectric element. Our device directly transduces between microwave frequency photons and phonons propagating in the silicon waveguide, providing a route for coupling to superconducting circuits. We probe the device at millikelvin temperatures through a superconducting microwave resonant matching cavity to reveal harmonics of the silicon waveguide and extract a piezoelectric coupling rate \(g/2\pi= 1.1\) megahertz and a mechanical coupling rate \(f/2\pi=5\) megahertz. Through time-domain measurements of the silicon mechanical modes, we observe energy relaxation timescales of \(T_{1,\text{in}} \approx 500\) microseconds, pure dephasing timescales of \(T_\phi \approx {60}\) microseconds and dephasing dynamics that indicate the presence of an underlying frequency noise process with a non-uniform spectral distribution. We measure phase noise cross-correlations between silicon mechanical modes and observe detuning-dependent positively-correlated frequency fluctuations. Our measurements provide valuable insights into the dynamics and decoherence characteristics of hybrid piezoelectric-silicon acoustic devices, and suggest approaches for mitigating and circumventing noise processes for emerging quantum acoustic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
13 pages, 4 main figures, 3 appendix figures
Long-Range Spin-Orbit-Coupled Magnetoelectricity in Type-II Multiferroic NiI\(_2\)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Weiyi Pan, Zefeng Chen, Dezhao Wu, Weiqin Zhu, Zhiming Xu, Lianchuang Li, Junsheng Feng, Bing-Lin Gu, Wenhui Duan, Changsong Xu
Type-II multiferroics, where spin order induces ferroelectricity, exhibit strong magnetoelectric coupling. However, for the typical 2D type-II multiferroic NiI\(_2\), the underlying magnetoelectric mechanism remains unclear. Here, applying generalized spin-current model, together with first-principles calculations and a tight-binding approach, we build a comprehensive magnetoelectric model for spin-induced polarization. Such model reveals that the spin-orbit coupling extends its influence to the third-nearest neighbors, whose contribution to polarization rivals that of the first-nearest neighbors. By analyzing the orbital-resolved contributions to polarization, our tight-binding model reveals that the long-range magnetoelectric coupling is enabled by the strong \(e_g\)-\(p\) hopping of NiI\(_2\). Monte Carlo simulations further predict a Bloch-type magnetic skyrmion lattice at moderate magnetic fields, accompanied by polar vortex arrays. These findings can guide the discovery and design of strongly magnetoelectric multiferroics.
Materials Science (cond-mat.mtrl-sci)
Turbulence-Induced Fluctuating Interfaces in Heterogeneously-Active Suspensions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Siddhartha Mukherjee, Kunal Kumar, Samriddhi Sankar Ray
We investigate the effects of heterogeneous (spatially varying) activity in a hydrodynamical model for dense bacterial suspensions, confining ourselves to experimentally realizable, simple, quenched, activity patterns. We show that the evolution of the bacterial velocity field under such activity patterning leads to the emergence of hydrodynamic interfaces separating spatially localized turbulence from jammed frictional surroundings. We characterise the intermittent and multiscale fluctuations of this interface and also investigate how heterogeneity influences mixing via the residence times of Lagrangian tracers. This work reveals how naturally occurring heterogeneities could decisively steer active flows into more complex configurations than those typically studied, opening up parallels to droplet dynamics, front propagation and turbulent mixing layers.
Soft Condensed Matter (cond-mat.soft), Chaotic Dynamics (nlin.CD), Computational Physics (physics.comp-ph), Fluid Dynamics (physics.flu-dyn)
10 pages, 5 figures
Quantum metric non-linear Hall effect in an antiferromagnetic topological insulator thin-film EuSn2As2
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Hung-Ju Tien, Hsin Lin, Liang Fu, Tay-Rong Chang
The quantum geometric structure of electrons introduces fundamental insights into understanding quantum effects in materials. One notable manifestation is the non-linear Hall effect (NLHE), which has drawn considerable interest for its potential to overcome the intrinsic limitations of semiconductor diodes at low input power and high frequency. In this study, we investigate NLHE stemming from the real part of the quantum geometric tensor, specifically the quantum metric, in an antiferromagnetic topological material, EuSn2As2, using density functional theory. Our calculations predict a remarkable NLHE arising from a symmetry-protected, single Type-II surface Dirac cone in the even-numbered-layer two-dimensional slab thin-film, yielding a non-linear Hall conductivity exceeding 20 mA/V2-an order of magnitude larger than previously reported. This single Dirac band dispersion represents the simplest model for generating NLHE, positioning the EuSn2As2 thin-film as a hydrogen atom for NLHE systems. Additionally, we observe NLHE from band-edge states near the Fermi level. Our findings also reveal that 30% phosphorus (P) doping can double the non-linear Hall conductivity. With its substantial and tunable NLHE, EuSn2As2 thin-films present promising applications in antiferromagnetic spintronics and rectification devices.
Materials Science (cond-mat.mtrl-sci)
Materials Today Quantum 5, 100027 (2025)
Curved crack paths are predicted by elastic-charges
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Oran Szachter, Emmanuel Siefert, Mokhtar Adda-Bedia, Eran Sharon, Michael Moshe
Predicting crack trajectories in brittle solids remains an open challenge in fracture mechanics due to the non-local nature of crack propagation and the way cracks modify their surrounding medium. Here, we develop a framework for analytically predicting crack trajectories, similar to predicting the motion of charged particles in external fields within Newtonian mechanics. We demonstrate that a crack can be described as a distribution of elastic charges, and within the framework of Linear Elastic Fracture Mechanics (LEFM), its interaction with the background stress can be approximated by a singular geometric charge at the crack tip. The cracks motion is then predicted as the propagation of this singular charge within the unperturbed stress field. We apply our approach to study crack trajectories near defects and validate it through experiments on flat elastomer sheets containing an edge dislocation. The experimental results show excellent agreement with theoretical predictions, including the convergence of curved crack trajectories toward a single focal point. We discuss future extension of our theory to the motion of multiple interacting cracks. Our findings highlight the potential of the elastic-charges approach to significantly advance classical fracture mechanics by enabling analytical solutions to problems traditionally requiring numerical methods.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci)
Spontaneous Chiral Symmetry Breaking in Polydisperse Achiral Near-Rigid Nematogens
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
William S. Fall, Henricus H. Wensink
Understanding chirality transfer from the molecular to the macroscopic scale poses a significant challenge in soft and biological condensed matter physics. Many nanorods of biological origin not only have chiral molecular features but also exhibit a spread in contour length leading to considerable size dispersity. On top of this, random backbone fluctuations are ubiquitous for non-rigid particles but their role in chirality transfer remains difficult to disentangle from that of their native chirality imparted by their effective shape or surface architecture. We report spontaneous entropy-driven chiral symmetry breaking from molecular simulations of cholesteric liquid-crystals formed from achiral bead-spring rods with a continuous spread in contour length and marginal chain bending. The symmetry-breaking is caused by long-lived chiral conformations of long rods undergoing chiral synchronization leading to a homochiral twisted nematic. A simple theory demonstrates that even without chiral synchronization, the presence of shape-persistent configurational fluctuations along with length-dispersity can be harnessed to generate non-zero chirality at moderate polydispersity.
Soft Condensed Matter (cond-mat.soft), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
Ultrashort 30-fs laser photoablation for high-precision and damage-free diamond machining
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Maksym Rybachuk, Bakhtiar Ali, Igor V. Litvinyuk
A 30-fs, 800 nm, 1 kHz femtosecond was used to photoablate diamond across radiant energy doses of 1 - 500 kJ/cm^2, with fluences of 10 - 50 J/cm^2 and, pulse counts from 100 to 10,000. The objective was to maximise material removal while minimising surface roughness (Ra) by operating above the photoablation threshold. Results demonstrate that 30-fs laser photoablation achieves Ra <0.1 , meeting both high- and ultra-high-precision machining standards, while maintaining surface integrity and preventing heat-affected zone (HAZ) damage. At 1 kJ/cm^2 (10 J/cm^2 fluence, 100 pulses), an Ra of 0.09 was achieved, satisfying ultra-high precision criteria (Ra <0.1 ). Additionally, doses below 10 kJ/cm^2 consistently met high-precision machining requirements (Ra <0.2 ). Photoablation efficiency peaked below 50 kJ/cm^2, after which material removal diminished, indicating non-linear process limitations. The sp3-diamond phase remained intact, as confirmed by the unchanged T2g Raman mode at 1332 cm^-1, with no detectable Raman G or D modes, confirming the absence of sp2-related graphitization, structural disorder, of nitrogen vacancy (NV) centre annealing. These findings establish 30 fs laser processing as a high-precision, damage-free approach for diamond machining, with promising applications in NV centre-containing quantum materials and advanced tooling.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
23 pages, 8 figures
Lifted TASEP: long-time dynamics,generalizations, and continuum limit
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-25 20:00 EST
Fabian H.L. Essler, Jeanne Gipouloux, Werner Krauth
We investigate the lifted TASEP and its generalization, the GL-TASEP. We analyze the spectral properties of the transition matrix of the lifted TASEP using its Bethe ansatz solution, and use them to determine the scaling of the relaxation time (the inverse spectral gap) with particle number. The observed scaling with particle number was previously found to disagree with Monte Carlo simulations of the equilibrium autocorrelation times of the structure factor and of other large-scale density correlators for a particular value of the pullback \(\alpha_{\rm crit}\). We explain this discrepancy. We then construct the continuum limit of the lifted TASEP, which remains integrable, and connect it to the event-chain Monte Carlo algorithm. The critical pullback \(\alpha_{\rm crit}\) then equals the system pressure. We generalize the lifted TASEP to a large class of nearest-neighbor interactions, which lead to stationary states characterized by non-trivial Boltzmann distributions. By tuning the pullback parameter in the GL-TASEP to a particular value we can again achieve a polynomial speedup in the time required to converge to the steady state. We comment on the possible integrability of the GL-TASEP.
Statistical Mechanics (cond-mat.stat-mech)
25 pages, 13 Figures
Tunable electron-electron interaction and anomalous enhancement of large-momentum scattering in moiré superlattices
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Using a microscopic model, we show that the electron-electron interaction of flat bands deviates significantly from the Coulomb interaction. In particular, we find that large-momentum scattering is enhanced at \(\theta\lesssim4^\circ\), with a non-monotonic momentum dependence appearing near the magic angle. For \(\theta \gtrsim 1.2^\circ\), the enhanced large-momentum scattering can be attributed to the compact Wannier function. On the other hand, for \(\theta\lesssim1.2^\circ\), the nonmonotonic momentum dependence of the interaction matrix cannot be explained by a simple Wannier orbital, indicating a nontrivial modification to the el-el interaction. Notably, the range of angles \(\theta\) where the large-momentum scattering is enhanced differs from the magic angles at which nearly-flat bands emerge, suggesting that the angle dependence of material properties provides information about the effect of interaction. The results highlight unusual features of the interaction in moiré graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Field-Modulated Crystal Transport in Altermagnetic Topological materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Xiuxian Yang, Jingming Shi, Shifeng Qian, Xiaodong Zhou, Yinwei Li
Altermagnetism (AM), a recently proposed third type of collinear magnetic phase, has garnered significant attention due to its extraordinary features, including nonrelativistic alternating spin-splitting, spin-degenerate nodal topology, and anisotropic crystal transport. Here, we explore the role of inherent altermagnetic topology in crystal transport phenomena (such as crystal Hall, Nernst, and thermal Hall effects) in several room-temperature altermagnets, including tetragonal V\(_2\)\(_2\)O ( = K, Rb, Cs; = S, Se, Te), RuO\(_2\), MnF\(_2\), as well as hexagonal CrSb and MnTe. Notably, in V\(_2\)\(_2\)O, the first experimentally realized layered altermagnets, crystal transport is governed by altermagnetic pseudonodal surfaces, emphasizing the purely topological contributions to crystal transport. Furthermore, crystal transport exhibits strong anisotropy relative to the N{é}el vector. Interestingly, we demonstrate that spin-canting, a unique method for selectively controlling the altermagnetic topology and crystal transport, can substantially enhance the magnitude of these phenomena while preserving the alternating spin characteristics in both real and momentum space. Our findings provide an effective strategy for manipulating crystal transport in altermagnets, offering valuable insights for their potential applications in spintronics and spin caloritronics.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Discovery of High-Temperature Superconducting Ternary Hydrides via Deep Learning
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-25 20:00 EST
Xiaoyang Wang, Chengqian Zhang, Zhenyu Wang, Hanyu Liu, Jian Lv, Han Wang, Weinan E, Yanming Ma
The discovery of novel high-temperature superconductor materials holds transformative potential for a wide array of technological applications. However, the combinatorially vast chemical and configurational search space poses a significant bottleneck for both experimental and theoretical investigations. In this study, we employ the design of high-temperature ternary superhydride superconductors as a representative case to demonstrate how this challenge can be well addressed through a deep-learning-driven theoretical framework. This framework integrates high-throughput crystal structure exploration, physics-informed screening, and accurate prediction of superconducting critical temperatures. Our approach enabled the exploration of approximately 36 million ternary hydride structures across a chemical space of 29 elements, leading to the identification of 144 potential high-Tc superconductors with predicted Tc > 200 K and superior thermodynamic stability at 200 GPa. Among these, 129 compounds spanning 27 novel structural prototypes are reported for the first time, representing a significant expansion of the known structural landscape for hydride superconductors. This work not only greatly expands the known repertoire of high-Tc hydride superconductors but also establishes a scalable and efficient methodology for navigating the complex landscape of multinary hydrides.
Superconductivity (cond-mat.supr-con), Computational Physics (physics.comp-ph)
Topologically cloaked magnetic colloidal transport
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Anna M. E. B. Rossi, Thomas Märker, Nico C. X. Stuhlmüller, Piotr Kuświk, Feliks Stobiecki, Maciej Urbaniak, Sapida Akhundzada, Arne J. Vereijken, Arno Ehresmann, Daniel de las Heras, Thomas M. Fischer
Cloaking is a method of making obstacles undetectable. Here we cloak unit cells of a magnetic pattern squeezed into an otherwise periodic pattern from a magnetically driven colloidal flow. We apply a time-periodic external magnetic field loop to an ensemble of paramagnetic colloidal particles on the deformed periodic magnetic pattern. There exist topological loops where the particles avoid to trespass the cloaked regions by robustly traveling around the cloak. Afterwards the ensemble of particles continues with a motion identical to the motion as if the distorted region were nonexistent and the ensemble would have trespassed the undeformed region. We construct the cloak by continuously squeezing new conformally mapped unit cells between those of the originally undeformed and periodic pattern. We find a cloaking/decloaking transition as a function of the size and shape of the newly squeezed-in region. A cloak is scalable to arbitrary size if the biholomorphic map from the undistorted periodic lattice to the region outside the cloak locally rotates by less than an angle of forty five degrees. The work generalizes cloaking from waves toward particles.
Soft Condensed Matter (cond-mat.soft)
Nature Communications, 16, 1828 (2025)
Spin-charge Kondo effect for a quantum dot with side coupled Majorana zero mode
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Haojie Shen, Wei Su, Mengnan Chen, Xiaoqun Wang
We investigate a minimal system consisting of a quantum dot coupled to a Majorana zero mode and a normal lead. We identify the underlying screening process as a novel spin-charge Kondo effect, where the low-energy spin and charge degrees of freedom of the Majorana zero mode-quantum dot subsystem are fully screened by those in the normal lead, resulting in the formation of a spin-charge singlet. An effective low-energy model is derived, with charge fluctuations appropriately accounted for. This spin-charge Kondo effect is found to be consistent with the spin-dependent Andreev/normal boundary conditions induced by the Majorana zero mode. We demonstrate that the anomalous substructure in the spectrum and thermodynamic properties is closely tied to the proportion of the charge component in the screening cloud. The spin-charge screening cloud exhibits scaling behavior analogous to that of traditional Kondo systems, though the sub-leading even-odd effect is subtly modified by the boundary conditions. These findings enhance our understanding of Kondo physics and resolve key debates on quantum dot nanostructures with Majorana zero modes.
Strongly Correlated Electrons (cond-mat.str-el)
Loop-current order through the kagome looking glass
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Rafael M. Fernandes, Turan Birol, Mengxing Ye, David Vanderbilt
In loop-current states, interacting electronic degrees of freedom collectively establish interatomic currents, in a rare example of magnetism in which spin degrees of freedom do not play the primary role. The main impact of such states on the electronic spectrum is not via the standard Zeeman term, but via the kinetic energy, in which hopping parameters develop non-trivial phases that break time-reversal symmetry. The recent proposal of loop-current states in kagome superconductors has stimulated renewed interest in this exotic type of magnetism. In this perspective, we use kagome materials as a scaffolding to frame the basic phenomenology of loop-current states. We provide an overview of the group-theoretical properties of loop currents, as well as of relevant microscopic models and ab initio methods. Particular emphasis is given to the comparison with spin-density waves in the presence of spin-orbit coupling, as well as to the anharmonic coupling with charge-density waves, which is present in systems with threefold rotational symmetry. We also provide a brief overview of the current status of loop-current order in kagome metals and discuss open challenges including their experimental detection and interplay with other orders.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
perspective paper
X-ray Thomson scattering studies on spin-singlet stabilization of highly compressed H-like Be ions heated to two million degrees Kelvin
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
M. W. C. Dharma-wardana, Dennis. D. Klug (NRC-Canada)
Experiments at the US National Ignition Facility (NIF) [Döppner et al., Nature {}, 270-275 (2023)] have created highly compressed hot hydrogen-like Be plasmas. Published analyses of the the NIF experiment have used finite-\(T\) multi-atom density-functional theory (DFT) with Molecular dynamics (MD), and Path-Integral Monte Carlo (PIMC) simulations. These methods are very expensive to implement and often lack physical transparency. Here we (i) relate their results to simpler first-principles average-atom results, (ii) establish the feasibility of rapid data analysis, with good accuracy and gain in physical transparency, and (iii) show that the NIF experiment reveals high-\(T\) spin-singlet pairing of hydrogen-like Be ions with near neighbours. Our analysis predicts such stabilization over a wide range of compressed densities for temperatures close to two million Kelvin. Calculations of structure factors \(S(k)\) for electrons or ions, the Raleigh weight and other quantities of interest to X-ray Thomson scattering are presented. We find that the NIF data at the scattering wavevector \(k_{sc}\) of 7.89 Å\(^{-1}\) are more consistent with a density of \(20\pm2\) g/cm\(^3\), mean ionization ${Z}=$3.25, at a temperature of \(\simeq\) 1,800,000 K than the 34 g/cm\(^3, \bar{Z}=3.4\) proposed by the NIF team. The relevance of ion-electron coupled-modes in studying small \(k_{sc}\) data is indicated.
Materials Science (cond-mat.mtrl-sci), Solar and Stellar Astrophysics (astro-ph.SR), Plasma Physics (physics.plasm-ph)
10 pages, 8 figures
Modulation of superconductivity across a Lifshitz transition in alternating-angle twisted quadrilayer graphene
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Isabelle Y. Phinney, Andrew Zimmerman, Zeyu Hao, Patrick J. Ledwith, Takashi Taniguchi, Kenji Watanabe, Ashvin Vishwanath, Philip Kim
We report electric field-controlled modulation of the Fermi surface topology and explore its effects on the superconducting state in alternating-angle twisted quadrilayer graphene (TQG). The unique combination of flat and dispersive bands in TQG allows us to simultaneously tune the band structure through carrier density, \(n\), and displacement field, \(D\). From density-dependent Shubnikov-de Haas quantum oscillations and Hall measurements, we quantify the \(D\)-dependent bandwidth of the flat and dispersive bands and their hybridization. In the high \(|D|\) regime, the increased bandwidth favors the single particle bands, which coincides exactly with the vanishing of the superconducting transition temperature \(T_c\), showing that superconductivity in TQG is strongly bound to the symmetry-broken state. For a range of lower \(|D|\) values, a Lifshitz transition occurs when the flat and dispersive band Fermi surfaces merge within the \(\nu=+2\) symmetry-broken state. The superconducting state correspondingly shows an enhanced \(T_c\), suggesting that the superconducting condensate is strongly dependent on the Fermi surface topology and density of states within this symmetry-broken state.
Strongly Correlated Electrons (cond-mat.str-el)
Callan-Rubakov effects in topological insulators
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Yusuke O. Nakai, Reuel Dsouza, Daichi Nakamura, Shu Hamanaka, Andreas P. Schnyder, Masatoshi Sato
The Callan-Rubakov effect describes monopole-catalyzed proton decay. While this effect is fundamental for quantum field theories, its experimental observation has remained far from reality. Here, we reveal a similar, but experimentally reachable, defect-catalysis of the quantum anomaly in topological materials. In particular, surface Dirac fermions on topological insulators develop a distinct localized state at the position of dislocations or \(\pi\)-fluxes, which mediates spin-flip time-reversal breaking scattering or absorption of electrons. Despite the Hermiticity of topological insulators, a non-Hermitian topological number guarantees the robust existence of the localized state. Our finding implies that non-magnetic defects may behave like magnetic impurities on surfaces of topological insulators. Using the K-theory classification, we generalize this condensed-matter version of the Callan-Rubakov effect to other classes of topological materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con), High Energy Physics - Theory (hep-th)
7+8 pages, 3+7 figures, 1+2 table
Unraveling Enhanced Superconductivity in Single-layer FeSe through Substrate Surface Terminations
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-25 20:00 EST
Qiang Zou, Gi-Yeop Kim, Jong-Hoon Kang, Basu Dev Oli, Zhuozhi Ge, Michael Weinert, Subhasish Mandal, Chang-Beom Eom, Si-Young Choi, Lian Li
Single-layer FeSe films grown on (001) SrTiO3 substrates have shown a significant increase in superconducting transition temperature compared to bulk FeSe. Several mechanisms have been proposed to explain such enhancement, including electron doping, interfacial electron-phonon coupling, and strong electron correlations. To pinpoint the primary driver, we grew FeSe films on SrTiO3 substrates with coexisting TiO2 and SrO surface terminations. Scanning tunneling spectroscopy revealed a larger superconducting gap of 17 meV for FeSe on TiO2 compared to 11 meV on SrO. Tunneling spectroscopy also showed a larger work function on SrO, leading to reduced charge transfer, as confirmed by angle-resolved photoemission spectroscopy. Scanning transmission electron microscopy revealed distinctive interfacial atomic-scale structures, with the Se-Fe-Se tetrahedral angle changing from 109.9° on SrO to 105.1° on TiO2. Compared to dynamical mean field theory calculations, these results suggest optimal electron correlations in FeSe/TiO2 for enhancing high-temperature superconductivity.
Superconductivity (cond-mat.supr-con)
Symmetry-breaking effects on spin-orbit torque switching in ferromagnetic semiconductors with perpendicular magnetic anisotropy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
This study explores the mechanisms of spin-orbit torque (SOT) switching in ferromagnetic semiconductors (FMS) with perpendicular magnetic anisotropy (PMA), emphasizing the impact of symmetry-breaking. Using micromagnetic simulations based on the Landau-Lifshitz-Gilbert (LLG) equation, we examine several symmetry-breaking factors, including bias field misalignment, interlayer exchange coupling, out-of-plane spin polarization, and tilted magnetic anisotropy. The results reveal that bias field misalignment relative to the film plane significantly distorts the SOT switching hysteresis. Additionally, intrinsic symmetry-breaking effects, such as internal coupling fields, out-of-plane spin polarization, and tilted anisotropy, facilitate field-free SOT (FF-SOT) switching without external bias fields. Each type of FF-SOT switching exhibits distinct characteristics, including hysteresis shifts, switching ratios, and saturated magnetization. This work emphasizes the role of symmetry-breaking in FF-SOT switching and offers fundamental information for interpreting FF-SOT switching observed from FMS films in experiments, contributing to the optimization of SOT efficiency and the advancement of spintronics technologies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Room-temperature field-tunable radiofrequency rectification in epitaxial SrIrO3 films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Liang Zhou, Zongzheng Du, Jinhua Wang, Pingbo Chen, Bicong Ye, Tao Feng, Jiahao Yang, Zehao Xiao, Meng Yang, Junxue Li, Wenqing Zhang, Hai-zhou Lu, Hongtao He
Although significant advancements have been made in wireless technologies and portable devices, it remains a challenge for high-frequency and nanowatt-level radiofrequency rectification. In this work, we report a pronounced radiofrequency rectification up to 37 GHz in nominally centrosymmetric SrIrO3 epitaxial films, with the minimum detectable power as low as ~300 nanowatts. Strikingly, the SrIrO3 rectifier is highly field-tunable and exhibits a strong in-plane field anisotropy, thus showing a unique advantage in broad-band radiofrequency rectification. The rectification effect can persist up to at least 360 K and shows a sensitive temperature dependence including a sign inversion. By a systematic study of the nonlinear transport properties of SrIrO3, it is further revealed that the radiofrequency rectification originates from the nonlinear Hall effect with the dominant contribution from field-induced Berry curvature dipole. Our work demonstrates the superior performance of the field-tunable SrIrO3 rectifiers, unleashing the great application potential of centrosymmetric materials in harvesting and detecting ambient electromagnetic energy.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
4 figures
Intrinsic vs. Extrinsic Magnetic Transitions in Sr3Ru2O7 films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
R. Choudhary, A. Rajapitamahuni, S. Guo, Qi. Jiang, J.-H. Chu, K. A. Mkhoyan, B. Jalan
In scientific research, both positive and negative results play crucial role in advancing the field. Negative results provide valuable insights that can guide future experiments and prevent repeated failures. Here we present our growth attempts of Sr3Ru2O7 thin films using the hybrid molecular beam epitaxy. X-ray diffraction suggests nominally phase-pure films. A combination of magnetoresistance and magnetization measurements exhibits an onset of ferromagnetism at 170 K and 100 K, along with a metamagnetic-like transition at 40 K. These results could initially be interpreted as intrinsic behavior of strain-engineered Sr3Ru2O7 films. However, detailed microstructural analysis reveals intergrowths of Sr2RuO4, Sr4Ru3O10, and SrRuO3 phases, dispersed throughout the film. Our findings suggest that the Sr3Ru2O7 films are likely paramagnetic, with the observed ferromagnetism arising from the Sr4Ru3O10 and SrRuO3 phases. Our results highlight the need for detailed microstructural analysis when interpreting new material properties influenced by strain and microstructure.
Materials Science (cond-mat.mtrl-sci)
16 pages
Anti-aligning Self-propelled Model of Two Species: Emergence of
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Takahiro Oki, Tetsuhiro S. Hatakeyama, Seiya Nishikawa, Shuji Ishihara, Toshinori Namba
Self-propelled particles with anti-aligning interactions generally do not form a polar order. However, in this Letter, we show that when multiple types of such particles coexist and interact through aligning interactions between different species, a global polar order can emerge through the formation of elongated clusters with alternating domains of each species. By developing a mean-field theory, we reveal the conditions for cluster formation and characterize the resulting patterns. Our findings highlight the critical role of inter-species interactions in the emergence of complex ordered states.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
5 pages, 3 figures
Localized Radiofrequency Heating for Enhanced Thermoelectric Energy Generation Using Natural Galena Ore
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Karthik R, Yiwen Zheng, Rajesh Kumar Sahu, Punathil Raman Sreeram, Soma Banik, Aniruddh Vashisth, Chandra Sekhar Tiwary
The efficiency of thermoelectric devices can be significantly enhanced by maintaining a stable temperature gradient, which can be achieved through localized heating. Radio waves serve as an ideal heat source for this purpose. In this study, we demonstrate the enhancement of thermoelectric performance in earth-abundant natural ore Galena (PbS) through localized radio frequency (RF) heating. RF heating experiments conducted at frequencies between and induced substantial localized heating in PbS, generating a temperature gradient of . This resulted in a Seebeck voltage of , approximately 13 times greater than the conventional Seebeck coefficient of PbS (). Additionally, a power factor of and an overall RF to thermoelectric conversion efficiency of 15% were achieved. Molecular dynamics simulations corroborate the experimental findings, providing insights into the mechanism of thermal transport and RF-induced heating in PbS. These results highlight the potential of localized RF heating as an effective strategy for enhancing thermoelectric performance, with promising implications for ambient thermoelectric energy harvesting applications.
Materials Science (cond-mat.mtrl-sci)
26 pages, 6 figures
Carrier Emission and Capture Competition mediated A(n)BC Recombination Model in Semiconductors with Multi-Level Defects
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Shanshan Wang, Menglin Huang, Su-Huai Wei, Xin-Gao Gong, Shiyou Chen
The ABC model has been widely used to describe the carrier recombination rate, in which the rate of non-radiative recombination assisted by deep-level defects is assumed to depend linearly on excess carrier density \(\Delta n\), leading to a constant recombination coefficient A. However, for multi-level defects that are prevalent in semiconductors, we demonstrate here that the rate should depend nonlinearly on \(\Delta n\). When \(\Delta n\) varies, the carrier capture and emission of defects can change the defect density distribution in different charge states, which can further change the carrier capture and emission rates of the defects and thus make the recombination rate depend non-linearly on \(\Delta n\), leading to an \(A(n)\) function. However, in many recent calculation studies on carrier recombination rate of multi-level defects, only carrier capture was considered while carrier emission from defect levels was neglected, causing incorrect charge-state distribution and misleading linear dependence of the rate on \(\Delta n\). For \(\text{V}_{\text{Ga}}\)-\(\text{O}_{\text{N}}\) in GaN and \(\text{Pb}_\text{I}\) in CsPbI\(_3\), our calculations showed that neglecting the carrier emission can cause the recombination rate underestimation by more than 8 orders of magnitude when \(\Delta n\) is \(10^{15}\) cm\(^{-3}\). Our findings suggest that the recent studies on carrier recombination assisted by multi-level defects should be revisited with carrier emission considered, and the widely-used \(ABC\) model should be reformed into the \(A(n)BC\) model.
Materials Science (cond-mat.mtrl-sci)
Optimization and Performance Evaluation of Cs2CuBiCl6 Double Perovskite Solar Cell for Lead-Free Photovoltaic Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Syeda Anber Urooj Wasti, Sundus Naz, Ammara Sattar, Asad Yaqoob, Ateeq ul Rehman, Fawad Ali, Shahbaz Afzal
In the previous decade, there has been a significant advancement in the performance of perovskite solar cells (PSCs), characterized by a notable increase in efficiency from 3.8% to 25%. Nonetheless, PSCs face many problems when we commercialize them because of their toxicity and stability. Consequently, lead-PSCs need an alternative solar cell with high performance and low processing cost; lead-free inorganic perovskites have been explored. Recent research showcased Cs2CuBiCl6, a lead-free inorganic double perovskite material with remarkable photoelectric characteristics and exceptional environmental robustness. To investigate the potential of Cs2CuBiCl6 material, the solar cell structure FTO/ETL/Cs2CuBiCl6/HTL/Au was used and analyzed through a solar cell capacitance simulator (SCAPS-1D). CeO2 is used as the Electron transport layer (ETL), and CuI is the Hole transport layer (HTL). Furthermore, the research examined the optimization of different parameters of the absorber layer (AL), such as thickness, defect density, electron affinity, band gap, and operational temperature. In the end, it has been noticed that by setting the temperature at 300 K and an electron affinity of 4.3 eV of the absorber layer, the PSCs achieve the highest efficiency of 24.51 %, FF of 43.01 %, Voc of 1.73V, and Jsc of 32.82mA/cm2. This is the highest Cs2CuBiCl6 double PSCs efficiency we've reached yet. In theoretical studies, 17.03% of PCE was achieved using Cs2CuBiCl6 as an active layer. The analysis underscores the significant potential of Cs2CuBiCl6 as an absorbing layer in developing highly efficient lead-free all-inorganic PSCs.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Optics (physics.optics)
Critical Dynamics of the Anderson Transition on Small-World Graphs
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-25 20:00 EST
Weitao Chen, Ignacio García-Mata, John Martin, Jiangbin Gong, Bertrand Georgeot, Gabriel Lemarié
The Anderson transition on random graphs draws interest through its resemblance to the many-body localization (MBL) transition with similarly debated properties. In this Letter, we construct a unitary Anderson model on Small-World graphs to characterize long time and large size wave-packet dynamics across the Anderson transition. We reveal the logarithmically slow non-ergodic dynamics in the critical regime, confirming recent random matrix predictions. Our data clearly indicate two localization times: an average localization time that diverges, while the typical one saturates. In the delocalized regime, the dynamics are initially non-ergodic but cross over to ergodic diffusion at long times and large distances. Finite-time scaling then allows us to characterize the critical dynamical properties: the logarithm of the average localization time diverges algebraically, while the ergodic time diverges exponentially. Our results could be used to clarify the dynamical properties of MBL and could guide future experiments with quantum simulators.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
5 pages, 3 figures
Emergent Dynamical Ising Transition in Diffusive Sandpiles
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-25 20:00 EST
Armin Makani, Morteza Nattagh Najafi
Minimally stable site (MSS) clusters play a dominant role in shaping avalanches in the self-organized critical (SOC) systems. The manipulation of MSS clusters through local smoothings (diffusion) alter the MSS landscape, suppressing rare avalanches and postponing them until they manifest as spanning avalanches. By leveraging the Inverse Ising problem, we uncover a duality between diffusive sandpiles and equilibrium statistical physics. Our analysis reveals an emergent magnetic instability in the dual Ising model, coinciding with the formation of spanning avalanches and marking a transition to a correlated percolation regime. At this point, the MSS loop soups exhibit fractal self-similarity and power-law distributions, while the effective pairwise interactions in the dual system vanish, signaling a magnetic transition characterized by abrupt changes in magnetization and spin susceptibility. Crucially, we show that diffusion fundamentally reshapes avalanche dynamics: the spatial anti-correlations of MSSs in standard SOC systems transform into positive correlations when diffusion is introduced. These findings bridge self-organized criticality, percolation theory, and equilibrium phase transitions, shedding new light on emergent criticality and large-scale correlations in non-equilibrium systems.
Statistical Mechanics (cond-mat.stat-mech)
Quantum dot-based device for high-performance magnetic microscopy and spin filtering in the Kondo regime
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Pierre Lombardo, Imam Makhfudz, Steffen Schäfer, Roland Hayn
We propose a nanoscale device consisting of a double quantum dot with a full exchange and pair hopping interaction. In this design, the current can only flow through the upper dot, but is sensitive to the spin state of the lower dot. The system is immersed in a highly inhomogeneous magnetic field, and only the bottom dot feels a substantial magnetic field, while the top dot experiences only a residual one. We show that our device exhibits very interesting magnetic field-dependent transport properties at low temperatures. The Kondo effect partially survives the presence of the magnetic field and allows to obtain conductances that differ by several orders of magnitude for the two spin types across the top dot. Interestingly, as a function of the magnetic field, our two-dot device changes from a spin singlet state to a spin triplet state, in which the amplitudes of the spin-dependent conductances are reversed. Our device is able to discriminate between positive and negative magnetic fields with a high sensitivity and is therefore particularly interesting for imaging the surface of anti-ferromagnetic (AF) insulating materials with alternated surface magnetic field, as well as for spin filtering applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Dynamics of soft interacting particles on a comb
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-25 20:00 EST
Davide Venturelli, Pierre Illien, Aurélien Grabsch, Olivier Bénichou
We study the dynamics of overdamped Brownian particles interacting through soft pairwise potentials on a comb-like structure. Within the linearized Dean-Kawasaki framework, we characterize the coarse-grained particle density fluctuations by computing their one- and two-point correlation functions. For a tracer particle constrained to move along the comb backbone, we determine the spatial correlation profile between its position and the density of surrounding bath particles. Furthermore, we derive the correction to the diffusion coefficient of the tracer due to interactions with other particles, validating our results through numerical simulations.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
19+19 pages, 3 figures
Unconventional topological Weyl-dipole phonon
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Jianhua Wang, Yang Wang, Feng Zhou, Wenhong Wang, Zhenxiang Cheng, Shifeng Qian, Xiaotian Wang, Zhi-Ming Yu
A pair of Weyl points (WPs) with opposite Chern numbers \({\cal{C}}\) can exhibit an additional higher-order \(Z_2\) topological charge, giving rise to the formation of a \(Z_2\) Weyl dipole. Owing to the nontrivial topological charge, \(Z_2\) Weyl dipoles should also appear in pairs, and the WPs within each \(Z_2\) Weyl dipole can not be annihilated when meeting together. As a novel topological state, the topological Weyl-dipole phase (TWDP) has garnered significant attention, yet its realization in crystalline materials remains a challenge. Here, through first-principles calculations and theoretical analysis, we demonstrate the existence of the Weyl-dipole phase in the phonon spectra of the \(P6_3\) type Y(OH)\(_3\). Particularly, the Weyl dipole in this system is protected by a quantized quadrupole moment, and it distinguished from conventional Weyl dipole, as it comprises an unconventional charge-3 WP with \({\cal{C}}=-3\) and three conventional charge-1 WPs with \({\cal{C}}=1\). Consequently, the Weyl-dipole phase in Y(OH)\(_3\) features unique two-dimensional (2D) sextuple-helicoid Fermi-arc states on the top and bottom surfaces, protected by the Chern number, as well as one-dimensional (1D) hinge states that connect the two Weyl dipoles along the side hinges, guaranteed by the quantized quadrupole moment. Our findings not only introduce a novel higher-order topological phase, but also promote Y(OH)\(_3\) as a promising platform for exploring multi-dimensional boundaries and the interaction between first-order and second-order topologies.
Materials Science (cond-mat.mtrl-sci)
Quantum effects in charge control of semiconductor surfaces as elucidated by ab initio calculations a review
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Stanisław Krukowski, Pawel Kempisty, Pawel Strak
Recent progress in the investigations of the charge role in semiconductor surfaces is reviewed. This is based on ab intio investigations. That include elucidation of Coulomb interaction of the separated subsystems, such as slab copies or far distant adsorbate and the slab, the bonding in the bulk and on the surface, standard and resonant. The quantum nature of the bonding leads to emergence of the external surface dipole, which was well recognized prior to these investigations. The role of the external dipole layer in the thermalization of the adsorbate is proposed and formulated. The internal dipole charge well known to exist at the surface were supplemented by new finding including the simulation of these dipole fields within slab model, pinning the Fermi level at the surface and the role of bulk and surface charge. of the bonding states. This could also occur at the activated complex point where the energy of these states could be increased into the vicinity of Fermi level or even higher so that this affects the energy barrier for diffusion. Therefore the explicit incorporation of quantum effects in the charge role in the semiconductor surfaces changes their properties considerably as described in this review.
Materials Science (cond-mat.mtrl-sci)
88 pages, 34 figures
Pinch-line spin liquids as layered Coulomb phases
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Naïmo Davier, Flavia A. Gómez Albarracín, H. Diego Rosales, Pierre Pujol, Ludovic D. C. Jaubert
Spin liquids form fluctuating magnetic textures which have to obey certain rules imposed by frustration. These rules can often be written in the form of a Gauss law, indicating the local conservation of an emergent electric field. In reciprocal space, these emergent Gauss laws appear as singularities known as pinch points, that are accessible to neutron-scattering measurements. But more exotic forms of electromagnetism have been stabilized in spin liquids, and in a few rare instances, these zero-dimensional singularities have been extended into one-dimensional pinch lines. Here we propose a simple framework for the design of pinch-line spin liquids in a layered structure of two-dimensional algebraic spin liquids. A plethora of models can be build within this framework, as exemplified by two concrete examples where our theory is confirmed by simulations, and where the rank of the tensorial gauge field is continuously varied along the pinch line, opening new avenues in fractonic matter. We conclude our letter with guidelines for experimental realizations.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 3 figures
Active Learning for Conditional Inverse Design with Crystal Generation and Foundation Atomic Models
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Zhuoyuan Li, Siyu Liu, Beilin Ye, David J. Srolovitz, Tongqi Wen
Artificial intelligence (AI) is transforming materials science, enabling both theoretical advancements and accelerated materials discovery. Recent progress in crystal generation models, which design crystal structures for targeted properties, and foundation atomic models (FAMs), which capture interatomic interactions across the periodic table, has significantly improved inverse materials design. However, an efficient integration of these two approaches remains an open challenge. Here, we present an active learning framework that combines crystal generation models and foundation atomic models to enhance the accuracy and efficiency of inverse design. As a case study, we employ Con-CDVAE to generate candidate crystal structures and MACE-MP-0 FAM as one of the high-throughput screeners for bulk modulus evaluation. Through iterative active learning, we demonstrate that Con-CDVAE progressively improves its accuracy in generating crystals with target properties, highlighting the effectiveness of a property-driven fine-tuning process. Our framework is general to accommodate different crystal generation and foundation atomic models, and establishes a scalable approach for AI-driven materials discovery. By bridging generative modeling with atomic-scale simulations, this work paves the way for more accurate and efficient inverse materials design.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Stable time rondeau crystals in dissipative many-body systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-25 20:00 EST
Zhuocheng Ma, Jin Yan, Hongzheng Zhao, Liang-You Peng
Driven systems offer the potential to realize a wide range of non-equilibrium phenomena that are inaccessible in static systems, such as the discrete time crystals. Time rondeau crystals with a partial temporal order have been proposed as a distinctive prethermal phase of matter in systems driven by structured random protocols. Yet, heating is inevitable in closed systems and time rondeau crystals eventually melt. We introduce dissipation to counteract heating and demonstrate stable time rondeau crystals, which persist indefinitely, in a many-body interacting system. A key ingredient is synchronization in the non-interacting limit, which allows for stable time rondeau order without generating excessive heating. The presence of many-body interaction competes with synchronization and a de-synchronization phase transition occurs at a finite interaction strength. This transition is well captured via a linear stability analysis of the underlying stochastic processes.
Statistical Mechanics (cond-mat.stat-mech)
High second harmonic generation in ferroelectric nematic liquid crystals by doping with optimally oriented chromophores
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
J. Ortega, C.L. Folcia, T. Sierra
We report on the second harmonic generation performance of a ferroelectric nematic fluid consisting of the prototype ferroelectric nematic liquid crystal, RM734 mixed with the classical chromophore Dispersed-Orange 3 at 5 %wt. The mixture exhibits an interesting mesomorphic behavior with a wide temperature range of the ferroelectric mesophase, high nematic order parameter and ease of alignment in cells. In the study, two fundamental wavelengths (1064 nm and 1574 nm) have been used in order to account for the second harmonic generation performance in transparent and absorbing regimens. The results have been very outstanding and are among the highest for liquid crystals so far. Specifically, second order susceptibility tensor components of up to 25 pmV-1 and 8.5 pmV-1 have been obtained in the absorbing and transparent regimens, respectively. The mixing of chromophores with ferroelectric nematic liquid crystals is then stablished as a promising strategy in the search of high-performance nonlinear-optical mesogens.
Soft Condensed Matter (cond-mat.soft), Optics (physics.optics)
20 pages, 2 figures
Phase coherence of charge-\(6e\) superconductors via a frustrated Kagome XY antiferromagnet
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-25 20:00 EST
Feng-Feng Song, Guang-Ming Zhang
Recent experimental evidence for the charge-\(6e\) condensed phase in kagome superconductors has generated significant interest. We investigate the unconventional superconductivity in the kagome superconductor \(\mathrm{CsV_3Sb_5}\), focusing on the emergence of charge-\(6e\) superconductivity (SC) at temperatures higher than the conventional charge-\(2e\) SC state. By modeling the phase coherence of the SC order parameter using a frustrated antiferromagnetic XY model on an emergent kagome lattice, we show that the condensation of fractional vortices with \(1/3\) vorticity stabilizes phase coherence in \(\exp(i3\theta)\), giving rise to the charge-\(6e\) SC state. Using a tensor network approach tailored for frustrated spin systems, we identify a Berezinskii-Kosterlitz-Thouless transition at \(T_c/J \simeq 0.075\), where the unbinding of \(1/3\) fractional vortex-antivortex pairs transforms the system from the charge-\(6e\) SC phase to the normal phase. Below \(T_c\), the \(1/3\) fractional vortex correlations exhibit power-law decay, while the integer vortex correlations decay exponentially, reflecting the dominance of charge-\(6e\) SC in the absence of charge-\(2e\) SC. Our results provide a theoretical understanding of the charge-\(6e\) SC in two-dimensional kagome superconductors, emphasizing the interplay between fractional vortices, frustration, and topology in stabilizing this exotic SC phase.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el)
6 pages, 4 figures
Chin. Phys. Lett. 42, 037401 (2025)
Investigating the relation between elastic and relaxation properties of dry, frictional granular media during shear deformation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Aurélien Rigotti, Véronique Dansereau, Jérôme Weiss
Using discrete element simulations based on molecular dynamics, we investigate the mechanical behavior of sheared, dry, frictional granular media in the "dense" and "critical" regimes. We find that this behavior is partitioned between transient stages and a final stationary stage. While the later is macroscopically consistent with the predictions of the viscous, \(\mu(I)\) rheology, both the macroscopic behavior during the transient stages and the overall microscopic behavior suggest a more complex picture. Indeed, the simulated granular medium exhibits a finite elastic stiffness throughout its entire shear deformation history, although topological rearrangements of the grains at the microscale translate into a partial degradation of this stiffness, which can be interpreted as a form of elastic damage. The relaxation of stresses follows a compressed exponential, also highlighting the role of elastic interactions in the medium, with residual stresses that depend on the level of elastic damage. The established relations between elastic and relaxation properties point to a complex rheology, characterized by a damage-dependent transition between a visco-elasto-plastic and a viscous behavior.
Soft Condensed Matter (cond-mat.soft)
20 pages, 22 Figures
Random Transverse Field Effects on Magnetic Noise in Spin Systems
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Yufei Pei, Claudio Castelnovo, Roderich Moessner
Motivated by experimental developments in non-Kramers spin ice materials and the unclear role of disorder therein, we study the impact of random transverse fields on the dynamics of correlated magnetic systems. We model the effect of dilute, randomly placed transverse fields on quantities such as magnetic noise/susceptibility and the diffusivity of topological excitations. We consider a random ferromagnetic Ising chain (RTFIC) as well as three-dimensional spin ice. At low temperatures, both exhibit (sub-)diffusive defect dynamics, i.e., of domain walls and magnetic monopoles, respectively. Introducing sparse transverse fields leads to the emergence of an additional timescale on the order of the single-spin flip time. We develop a Lindbladian framework that combines Monte Carlo simulations and exact diagonalization which allows us to characterize the dynamics and develop an analytical understanding of the phenomenon. This framework can be benchmarked in detail for the RTFIC. Our findings provide insights into the magnetization dynamics of disordered non-Kramers oxides, such as oxygen-diluted Ho\(_2\)Ti\(_2\)O\(_7\), and offer a framework for interpreting experimental observations in these systems.
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 10 figures
Interstitials as a key ingredient for P segregation to grain boundaries in polycrystalline \(α\)-Fe
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Amin Reiners-Sakic, Alexander Reichmann, Christoph Dösinger, Lorenz Romaner, David Holec
The segregation of solutes to grain boundaries can significantly influence material behavior. Most previous computational studies have concentrated on substitutional solute segregation, neglecting interstitial segregation due to its increased complexity. The site preference, interstitial or substitutional, for P segregation in \(\alpha\)-Fe still remains under debate. In this work, we investigate the full GB-segregation spectrum for both substitutional and interstitial GB sites in a polycrystalline atomistic structure of ferrite with the aid of classical interatomic potentials combined with machine learning techniques. The method is qualitatively tested for H and Ni, where the segregation behavior in \(\alpha\)-Fe is well understood. Our findings for P show that segregation to both types of GB sites is possible, with a preference for the substitutional sites based on the mean segregation energy. However, due to the much larger number of interstitial sites, interstitial segregation significantly contributes to the GB enrichment with P. This underscores the importance of considering interstitial P segregation in addition to the substitutional one. Furthermore, we also argue that equally important for quantitative predictions (that agree with experimental data) is to get a representative spectrum of the segregation energies.
Materials Science (cond-mat.mtrl-sci)
14 pages, 4 figures
Status of Iron Based Superconductors: characteristics and relevant properties for applications
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-25 20:00 EST
Since the discovery of iron-based superconductors (IBSs) on LaFePO in 2006, many types of IBSs have been fabricated. IBSs have usually been compared to cuprates and MgB2, and the methodology of research developed by them have been implemented to IBSs. As a result, many similarities between IBSs and cuprates have been revealed, e.g., the parent compounds being antiferromagnets and grain boundaries being weak-links to some extent. On the other hands, the distinct features of IBSs are highlighted as multiband superconductors (i.e., the 5 bands of Fe 3d orbital crossing Fermi level) and extended s-wave symmetry. Additionally, some of the IBSs are topological superconductors that can be possible platforms for quantum computing. In this paper, an overview of IBS research and development in the last 18 years will be reported, involving characteristics of IBSs as well as strategies of increasing the superconducting transition temperature and critical current density.
Superconductivity (cond-mat.supr-con)
ASC2024, Plenary talk
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 35, NO. 5, 7400109, AUGUST 2025
Proximity Effects Between the Graphene Quasicrystaland Magic-Angle Twisted Bilayer Graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Pedro Alcázar Guerrero, Viet-Hung Nguyen, Aron W. Cummings, Jean-Christophe Charlier, Stephan Roche
We report a numerical study of graphene heterostructures comprised of three individual layers twisted by either the magic angle of $\(1.1\)^$, or $\(30^\circ\), corresponding to the graphene quasicrystal. The heterostack is modeled using realistic structural and tight-binding models, while transport properties are calculated in both clean and disordered systems containing up to $$8 million atoms. The weak interaction between different layers allows us to scrutinize the electronic mixing of flat bands and quasicrystalline states, which are altered differently in the low- and high-energy regimes and provide a new type of hybrid physics to be explored.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 pages, 6 figures
Theory of Nonlocal Transport from Nonlinear Valley Responses
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Jin Cao, Hui Wang, Shen Lai, Cong Xiao, Shengyuan A. Yang
We develop a theory for the nonlocal measurement of nonlinear valley Hall effect. Different from the linear case where the direct and the inverse processes are reciprocal, we unveil that the nonlinear inverse valley Hall effect needed to generate nonlocal voltage signal must have a distinct symmetry character and involve distinct mechanisms compared to the nonlinear valley Hall response it probes. Particularly, it must be valley-even, in contrast to both linear and nonlinear valley Hall effects which are valley-odd. Layer groups that permit such nonlocal valley responses are obtained via symmetry analysis, and formulas for the nonlocal signals are derived. In the presence of both linear and nonlinear valley responses, we show that the different responses can be distinguished by their distinct scaling behaviors in the different harmonic components, under a low-frequency ac driving. Combined with first-principles calculations, we predict sizable nonlocal transport signals from nonlinear valley responses in bilayer \(T_{d}\)-WTe\(_{2}\). Our work lays a foundation for nonlocal transport studies on the emerging nonlinear valleytronics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Mechanical non-reciprocity programmed by shear jamming in soft composite solids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Chang Xu, Shuaihu Wang, Hong Wang, Xu Liu, Zemin Liu, Yiqiu Zhao, Wenqi Hu, Qin Xu
Mechanical non-reciprocity-manifested as asymmetric responses to opposing mechanical stimuli-has traditionally been achieved through intricate structural nonlinearities in metamaterials. However, continuum solids with inherent non-reciprocal mechanics remain underexplored, despite their promising potential for applications such as wave guiding, robotics, and adaptive materials. Here, we introduce a design principle by employing the shear jamming transition from granular physics to engineering non-reciprocal mechanics in soft composite solids. Through the control of the interplay between inclusion contact networks and matrix elasticity, we achieve tunable, direction-dependent asymmetry in both shear and normal mechanical responses. In addition to static regimes, we demonstrate programmable non-reciprocal dynamics by combining responsive magnetic profiles with the anisotropic characteristics of shear-jammed systems. This strategy enables asymmetric spatiotemporal control over motion transmission, a previously challenging feat in soft materials. Our work establishes a novel paradigm for designing non-reciprocal matter, bridging granular physics with soft material engineering to realize functionalities essential for mechano-intelligent systems.
Soft Condensed Matter (cond-mat.soft), Applied Physics (physics.app-ph)
Sliding ferroelectric control of unconventional magnetism in stacked bilayers
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Yongqian Zhu, Mingqiang Gu, Yuntian Liu, Xiaobing Chen, Yuhui Li, Shixuan Du, Qihang Liu
The control of unconventional magnetism, which displays an antiferromagnetic configuration with ferromagnetism-like properties, has drawn intense attention for advancing antiferromagnetic spintronics. Here, through symmetry analysis, we propose a general stacking rule, characterized by a connection operator linking two stacked bilayers, for controlling unconventional magnetism via sliding ferroelectricity. Such rule enables the simultaneous switching of both electric polarization and nonrelativistic spin splitting or anomalous Hall effect in altermagnets, a class of collinear unconventional magnets. By comprehensively surveying the 80 layer groups, we identify all the stacking orders that allow for such two types of simultaneous switching. Combined with first-principles calculations, we demonstrate the sliding ferroelectric control of spin polarization and anomalous Hall effect in the altermagnetic AgF2 bilayer. Our work provides a symmetry strategy for achieving ferroelectric control of unconventional magnetism in bilayer systems and opens avenues for exploring new types of magnetoelectric coupling.
Materials Science (cond-mat.mtrl-sci)
Insights into Formation of Bicontinuous Emulsion Gels via in-situ (Ultra-)Small Angle X-ray Scattering
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Meyer T. Alting, Dominique M.E. Thies-Weesie, Alexander M. van Silfhout, Mariska de Ruiter, Theyencheri Narayanan, Martin F. Haase, Andrei V. Petukhov
Nanostructured materials formed via kinetically controlled self-assembly processes gather more interest nowadays. Bicontinuous emulsion gels stabilized by colloidal particles, called bijels, are attractive materials in soft-matter as they combine bulk properties of two immiscible liquids into an interwoven network structure. The limited understanding of the complex formation phenomena of bijels restricts the control over the synthesis, and so its applicability. In this work, in-situ (ultra-) small-angle X-ray scattering is applied to gain insight into the phase separation and self-assembly kinetics of bijels formed via solvent transfer induced phase separation. An X-ray compatible microfluidic setup allows accessing the process kinetics with a millisecond resolution. The formation of such bijels is shown to occur via three consecutive steps related to fluid mechanics, nanoparticle self-assembly and liquid-liquid phase separation. This time-resolved monitor technique offers valuable insights into the structural evolution of kinetically controlled materials and enhances our understanding of the formation of bicontinuous emulsion gels.
Soft Condensed Matter (cond-mat.soft)
Both manuscript and Supporting Information in one document, total 32 pages, 3 figures in main text, remaining in SI
Numerical study of synaptic behavior in amorphous HfO2-based ferroelectric-like FETs generated by voltage-driven ion migration
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Juan Cuesta-Lopez, Mohit D. Ganeriwala, Enrique G. Marin, Alejandro Toral-Lopez, Francisco Pasadas, Francisco G. Ruiz, Andres Godoy
The continuous effort in making artificial neural networks more alike to human brain calls for the hardware elements to implement biological synapse-like functionalities. The recent experimental demonstration of ferroelectric-like FETs promises low-power operation as compared to the conventional ferroelectric switching devices. This work presents an in-house numerical tool, which self-consistently solves the electrostatics and time-dependent electronic and ionic transport. The tool is exploited to analyze the effect that various physical parameters such as mobility and ion concentration could have on the design of the ferroelectric-like FETs. Their suitability in emulating different functions of the biological synapses is also demonstrated.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
19 pages, 8 figures, 1 table, paper
J. Appl. Phys. 136, 124501 (2024)
Directional propagation of quantum Hall viscous fluid by nano-structural engineering
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Hiroshi Funaki, Ai Yamakage, Ryotaro Sano, Mamoru Matsuo
We present a microscopic theory of the viscous electron fluid in the quantum Hall state based on the nonequilibrium Green's function method and the von Neumann lattice representation. This approach permits the formulation of hydrodynamic equations in the strong field regime that accommodates arbitrary boundary conditions. We demonstrate nonreciprocal transport resulting from the interplay between magnetic field-induced viscosity and device geometry in a notched system. Our results will offer a powerful tool for studying the nonperturbative effects of magnetic fields on electron viscous fluids.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Defects in the -Ga2O3(-201)/HfO2 MOS system and the effect of thermal treatments
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Khushabu. S. Agrawal, Paolo LaTorraca, Jonas Valentijn, Roberta Hawkins, Adam A. Gruszecki, Joy Roy, Vasily Lebedev, Lewys Jones, Robert M. Wallace, Chadwin D. Young, Paul K. Hurley, Karim Cherkaoui
We have investigated the properties of the -Ga2O3(-201)/HfO2/Cr/Au MOS (metal-oxide-semiconductor) system after annealing (450oC) in different ambient conditions (forming gas, N2 and O2). Defect properties have been analyzed using an approach combining experimental impedance measurements with physics-based simulations of the capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics of -Ga2O3/HfO2 MOS capacitors. This approach enabled us to detect two defect bands in HfO2 characterized by thermal ionization energies of ~1.1eV (acceptor-like) and ~2eV (donor-like) attributed to a polaronic self-trapping state and an oxygen vacancy in HfO2, respectively. This study demonstrates how thermal treatments affect the energy distributions and densities of the observed defects. The adopted methodology also enabled the extraction of the spatial distribution of defects across the HfO2 thickness and Cr/HfO2 interface. The high concentration of oxygen vacancies close to the Cr/HfO2 interface extracted from experimental and simulated electrical data is confirmed by in-situ XPS analysis which shows how Cr is scavenging oxygen from the HfO2 and creating the donor band confined near the Cr/HfO2 interface. This donor band density is observed to be reduced after annealing as per simulation and unchanged for different annealing conditions. We speculate this may be due to the formation of dense films and polyforms of HfO2 under different ambient as revealed by high-resolution TEM images.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Main article: 23 pages, 6 figures, Supporting information:7 pages, 5 Figures
Josephson vortex system in a flux-flow regime in electron doped high-Tc superconductor Nd(2-x)CexCuO4
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-25 20:00 EST
T. B. Charikova, A. M. Bartashevich, V. N. Neverov, M. R. Popov, N. G. Shelushinina, A.A. Ivanov
For an epitaxial film of an electron-doped superconductor Nd(2-x)CexCuO4 (x=0.145), in a mixed state, a well-defined step structure is observed on the dependence of the c-axis flux-flow resistance on the magnetic field parralel to CuO2 layers. It is shown that in the region of a free flow of Josephson vortices, the structure is periodic with a period of deltaB~Phi0/(lambdaablambdac). It is essential that the magnetic penetration depths in the ab-plane (lambdaab) and along the c-axis (lambdac) determine the sizes of the Josephson vortices in the Lawrence-Doniach model for an anisotropic layered superconductor.
Superconductivity (cond-mat.supr-con)
26 pages, 11 figures, 1 table
Electronic and structural properties of atomically thin metallenes
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Kameyab Raza Abidi, Pekka Koskinen
Although metallic elements favor three-dimensional (3D) geometries due to their isotropic, metallic bonding, experiments have reported metals also with two-dimensional (2D) allotropes, the so-called metallenes. And while bulk metals' electronic and structural properties are well known, the corresponding knowledge for atomically thin metallenes remains scattered. Therefore, in this work, we use density-functional theory to investigate the electronic and structural properties of 45 elemental metals with honeycomb, square, and hexagonal lattices, along with their buckled counterparts, resulting in a comprehensive catalog of 270 metallenes with their properties. We systematically present their structural, energetic, and electronic structure properties and discuss similarities and differences compared to their 3D counterparts. As a result, simple and noble metals exhibit similar characteristics and lack buckled hexagonal lattice. Apart from scattered exceptions, the trends in several properties, such as bond lengths, cohesion energies, and projected densities of states, are governed by coordination numbers and exhibit systematic patterns. This systematic reporting provides a necessary reference for the selection and categorization of metallenes for further experimental efforts to develop them for catalytic, sensing, plasmonic, and nanoelectronics applications.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
15 pages, 10 figures
Electron. Struct. 7 015004 (2025)
Structural Anisotropy Stabilises Asymmetric Beating in Instability Driven Filaments
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Bethany Clarke, Yongyun Hwang, Eric E Keaveny
Asymmetries and anisotropies are widespread in biological systems, including in the structure and dynamics of cilia and eukaryotic flagella. These microscopic, hair-like appendages exhibit asymmetric beating patterns that break time-reversal symmetry needed to facilitate fluid transport at the cellular level. The intrinsic anisotropies in ciliary structure can promote preferential beating directions, further influencing their dynamics. In this study, we employ numerical simulation and bifurcation analysis of a mathematical model of a filament driven by a follower force at its tip to explore how intrinsic curvature and direction-dependent bending moduli impact filament dynamics. Our results show that while intrinsic curvature is indeed able to induce asymmetric beating patterns when filament motion is restricted to a plane, this beating is unstable to out of plane perturbations. Furthermore, we find that a 3D whirling state seen for isotropic filament dynamics can be suppressed when sufficient asymmetry or anisotropy are introduced. Finally, for bending moduli ratios as low as 2, we demonstrate that combining structural anisotropy with intrinsic curvature can stabilise asymmetric beating patterns, highlighting the crucial role of anisotropy in ciliary dynamics.
Soft Condensed Matter (cond-mat.soft)
28 pages, 10 figures
Leveraging recurrence in neural network wavefunctions for large-scale simulations of Heisenberg antiferromagnets: the square lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
M. Schuyler Moss, Roeland Wiersema, Mohamed Hibat-Allah, Juan Carrasquilla, Roger G. Melko
Machine-learning-based variational Monte Carlo simulations are a promising approach for targeting quantum many body ground states, especially in two dimensions and in cases where the ground state is known to have a non-trivial sign structure. While many state-of-the-art variational energies have been reached with these methods for finite-size systems, little work has been done to use these results to extract information about the target state in the thermodynamic limit. In this work, we employ recurrent neural networks (RNNs) as a variational ansätze, and leverage their recurrent nature to simulate the ground states of progressively larger systems through iterative retraining. This transfer learning technique allows us to simulate spin-\(\frac{1}{2}\) systems on lattices with more than 1,000 spins without beginning optimization from scratch for each system size, thus reducing the demands for computational resources. In this study, we focus on the square-lattice antiferromagnetic Heisenberg model (SLAHM), where it is possible to carefully benchmark our results. We show that we are able to systematically improve the accuracy of the results from our simulations by increasing the training time, and obtain results for finite-sized lattices that are in good agreement with the literature values. Furthermore, we use these results to extract accurate estimates of the ground-state properties in the thermodynamic limit. This work demonstrates that RNN wavefunctions can be used to accurately study quantum many-body physics in the thermodynamic limit.
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn), Quantum Physics (quant-ph)
18 pages, 13 figures, 6 tables
Highly correlated electronic state in a ferrimagnetic quadruple perovskite CuCu\(_3\)Fe\(_2\)Re\(_2\)O\(_{12}\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
A. I. Poteryaev, Z. V. Pchelkina, S. V. Streltsov, Y. Long, V. Yu. Irkhin
Recently synthesized quadruple perovskite CuCu\(_3\)Fe\(_2\)Re\(_2\)O\(_{12}\) possesses strong ferromagnetism and unusual electron properties, including enhanced electronic specific heat. Application of the first principles electronic structure approaches unambiguously shows importance of the many-body effects in this compound. While CuCu\(_3\)Fe\(_2\)Re\(_2\)O\(_{12}\) is half-metallic ferrimagnet in the DFT+U method, in the density functional theory (DFT) combined with the dynamical mean-field theory (DMFT) it appears to be a metal. Strong correlations lead to a renormalization of electronic spectrum and formation of incoherent states close to the Fermi level. Electronic specific heat and magnetic properties obtained in the DFT+DMFT approach are in better agreement with available experimental data than derived by other band structure techniques.
Strongly Correlated Electrons (cond-mat.str-el)
5 pages
JETP Letters 121, 67-71 (2025)
Universal charge and spin Drude weights in one-dimensional Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Jia-Jia Luo, Sagarika Basak, Han Pu, Xi-Wen Guan
Drude weight (DW) is one of the most important quantities characterizing the quantum transport properties of many-body systems. Despite of intense studies of many decades, there still lacks rigorous understanding of transport behavior for various quantum phases at low temperatures. Here we report on universal properties of DWs in one-dimensional repulsive Fermi-Hubbard model with arbitrary magnetic fields. In addition to the usual charge and spin DWs, we also construct the cross DW that captures the cross influences between the two degrees of freedom in the transport dynamics, showing a subtle spin and charge coupling effect. Our analytical expressions of the DWs at different Tomonaga-Luttinger liquid phases essentially establish general relations between the Luttinger parameters and the DWs. We further obtain explicit universal critical scaling laws for DWs across various phase boundaries and propose an experimental protocol to measure the this http URL find that the DWs obtained from the direct numerical simulation of this protocol show qualitatively good agreement with the Bethe ansatz results.
Strongly Correlated Electrons (cond-mat.str-el)
6+21 pages, 4+1 figures
Importance of ligand on-site interactions for the description of Mott-insulators in DFT+DMFT
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Alberto Carta, Anwesha Panda, Claude Ederer
Calculations combining density functional theory (DFT) and dynamical mean-field theory (DMFT) for transition metal (TM) oxides and similar compounds usually focus on improving the description of the TM \(d\) states. Here, we emphasize the importance of also accounting for corrections of the ligand \(p\) states. We demonstrate that focusing exclusively on an improved description of the TM \(d\) states results in difficulties to obtain the correct insulating behavior for a variety of materials, and requires to use values for the local interaction parameters that are inconsistent with values obtained using, e.g., the constrained random phase approximation (cRPA). Importantly, these considerations not only apply to cases where the \(p\) states are explicitly included in the DMFT low-energy subspace, but also to cases which only include so-called frontier bands with dominant TM \(d\) character. We demonstrate that, to a large part, these inconsistencies arise from the use of local/semi-local DFT as starting point for computing interaction parameters within cRPA, and we show that applying a simple empirical correction to the O \(p\) and other low energy states not included in the correlated subspace results in improved values for the interaction parameters that then allow to obtain the correct insulating behavior. For the cases where the ligand states are included in the DMFT subspace, we show that even an approximate but realistic Hartree-Fock-like correction applied to the O \(p\) states leads to a correct and, most importantly, also a quantitatively consistent DFT+DMFT description of typical Mott insulators such as LaTiO\(_3\), LaVO\(_3\), or the perovskite rare-earth nickelates, \(R\)NiO\(_3\).
Strongly Correlated Electrons (cond-mat.str-el)
Training and re-training liquid crystal elastomer metamaterials for pluripotent functionality
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Savannah D. Gowen, Elina Ghimire, Charlie A. Lindberg, Ingrid S. Appen, Stuart J. Rowan, Sidney R. Nagel
Training has emerged as a promising materials design technique in which function can be acheived through repeated physical modification of an existing material rather than by direct chemical functionalization, cutting or reprocessing. This work investigates both the ability to train for function and then to erase that function on-demand in macroscopic metamaterials made from liquid crystal elastomers (LCEs). We first show that the Poisson's ratio of these disordered arrays can be tuned via directed aging to induce an auxetic response. We then show that the arrays can be reset and re-trained for another local mechanical function, allostery, thus demonstrating pluripotent functionality.
Materials Science (cond-mat.mtrl-sci), Disordered Systems and Neural Networks (cond-mat.dis-nn), Soft Condensed Matter (cond-mat.soft)
6 pages, 4 figures
Particle geometry space: An integrated characterization of particle shape, surface area, volume, specific surface, and size distribution
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
Particle size and shape are the key 3D particle geometry parameters that govern the complex behavior of granular materials. The effect of these geometry parameters has often been examined in isolation, e.g., through separate analysis of particle size distribution (PSD) and shape distribution, leading to an unaddressed knowledge gap. Beyond size and shape, 3D particle geometry also encompasses attributes such as surface area and volume (or collectively, the surface-area-to-volume ratio, which is also referred to as specific surface). To comprehensively understand the influence of particle geometry on the behavior of granular materials, it is important to integrate these parameters, ideally into a single analytical framework. To this end, this paper presents a new approach, Particle Geometry Space (PGS), formulated based on the principle that the four 3D particle geometry attributes - volume, surface area, size, and shape - can be uniformly represented as a function of specific surface. This space not only encompasses all 3D particle geometry attributes but also extends its scope by integrating the conventional PSD concept. This innovation enables engineers and researchers who are already familiar with PSD to perform a more systematic characterization of 3D particle geometries. The paper (i) discusses the limitations of existing methods for characterizing particle geometry, (ii) offers an overview of the PGS, (iii) proposes a method for integrating PSD into the PGS, and (iv) demonstrates its application with a set of 3D mineral particle geometry data.
Soft Condensed Matter (cond-mat.soft)
16 pages, 11 figures
Stabilization of Fermi-liquid behavior by interactions in disordered metals
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Arianna Poli, Simone Fratini, Jennifer Coulter, Andrew J. Millis, Sergio Ciuchi
We study the interplay of electron-electron and electron-disorder scattering in correlated Fermi liquids by the disordered Hubbard model using dynamical mean-field theory with an IPT-CPA solver. We find significant violations of Matthiessen's rule (additivity of scattering mechanisms) which we explain in terms of the screening of the disorder potential by interactions, leading to a protection of the electron-electron inelastic scattering rate against disorder. We also show that large disorder can lead to a surprising enhancement of the electron-electron scattering that contrasts with the competition seen in the elastic channel. Our results compare positively with available resistivity data in the disordered Fermi liquid phase of the correlated organic metals \(\kappa\)-(ET)\(_{2}\)X, and rationalize the strong sample dependence of the \(T^2\) coefficients observed in the resistivity of correlated perovskite oxides such as SrVO\(_3\).
Strongly Correlated Electrons (cond-mat.str-el), Disordered Systems and Neural Networks (cond-mat.dis-nn)
6 pages, 5 figures
Additional jamming transition in 2D bidisperse granular packings
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-25 20:00 EST
We present a jamming diagram for 2D bidisperse granular systems, capturing two distinct jamming transitions. The first occurs as large particles form a jammed structure, while the second, emerging at a critical small-particle concentration, \(X_{\mathrm{S}}^{\ast} \approx 0.21\), and size ratio, \(\delta^{\ast} \approx 0.25\), involves small particles jamming into the voids of the existing large-particle structure upon further compression. Below this threshold, small particles fill voids within the large-particle network, increasing packing density. Beyond this point, excess small particles disrupt efficient packing, resulting in looser structures. The alignment of these findings with 3D results suggests a general geometric mechanism governing the second jamming transition.
Soft Condensed Matter (cond-mat.soft), Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
5 pages, 4 figures (submitted to Physical Review Research)
Mechanism of Charge Transport in Mixed-Valence 2D Layered Hybrid Bronze Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Suchona Akter, Mohammad R. Momeni
Two-dimensional layered bronze (HB) materials are a new class of mixed-valence hybrid organic-inorganic metal oxides that demonstrate great potential as advanced functional materials for next-generation electronics. Recently, new hybrid vanadium bronze materials, (EV)V8O20 and (MV)V8O20, EV = ethyl viologen and MV = methyl viologen, have been introduced, with EV having ~3 orders of magnitude higher electrical conductivity than the MV system. Given their identical inorganic V-O layers and similar reduction potentials, the observed large difference in electrical conductivities is puzzling. Here, through accurate first-principles calculations coupled with MACE machine learning molecular dynamics (MD) simulations validated by accurate ab initio MD simulations, we provide mechanistic molecular-level insights into dominant charge transport and electrical conductivity pathways in these materials. Our detailed structural and electronic properties data identifies factors contributing to this significant difference in electrical conductivities of these materials. Our findings in this work offer clues and provide valuable insights into improving the electrical conductivity of hybrid bronze and similar materials in order to guide the design of next-generation materials with enhanced properties for future electronic and thermoelectric applications.
Materials Science (cond-mat.mtrl-sci)
Time-dependent global sensitivity analysis of the Doyle-Fuller-Newman model
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Elia Zonta, Ivana Jovanovic Buha, Michele Spinola, Christoph Weißinger, Hans-Joachim Bungartz, Andreas Jossen
The Doyle-Fuller-Newman model is arguably the most ubiquitous electrochemical model in lithium-ion battery research. Since it is a highly nonlinear model, its input-output relations are still poorly understood. Researchers therefore often employ sensitivity analyses to elucidate relative parametric importance for certain use cases. However, some methods are ill-suited for the complexity of the model and appropriate methods often face the downside of only being applicable to scalar quantities of interest. We implement a novel framework for global sensitivity analysis of time-dependent model outputs and apply it to a drive cycle simulation. We conduct a full and a subgroup sensitivity analysis to resolve lowly sensitive parameters and explore the model error when unimportant parameters are set to arbitrary values. Our findings suggest that the method identifies insensitive parameters whose variations cause only small deviations in the voltage response of the model. By providing the methodology, we hope research questions related to parametric sensitivity for time-dependent quantities of interest, such as voltage responses, can be addressed more easily and adequately in simulative battery research and beyond.
Materials Science (cond-mat.mtrl-sci), Computation (stat.CO)
Spin noise reveals spin dynamics and recharging of lead halide perovskite nanocrystals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
V. O. Kozlov, I. A. Smirnov, M. S. Kuznetsova, E. V. Kolobkova, G. G. Kozlov, V. S. Zapasskii, D. S. Smirnov, I. I. Ryzhov
The lead halide perovskite nanocrystals embedded into a glass matrix exhibit strong interaction with light and demonstrate exceptional optical and spin related features along with long-term chemical and physical stability. We apply the spin noise spectroscopy technique which offers a number of specific opportunities to study the spin system of CsPbI\(_3\) nanocrystals in a fluorophosphate glass matrix. A pronounced spin precession peak with an isotropic \(g\)-factor absolute value of 2.7 and record dephasing time of T\(_{2\text{,e}}\) = 2.7 ns is ascribed to resident electrons in the perovskite nanocrystals. The experimentally observed Faraday rotation noise with no noise of ellipticity is explained by saturation of the inhomogeneously broadened optical transition. Increasing the probe intensity, we went beyond the non-perturbative regime and observed a number of light-induced effects. In particular, the illumination with shorter wavelength light gives rise to a persistent recharging of the quantum dots by holes (\(|g|=0.17\) and T\(^\ast_{2\text{,h}}\) = 1.4 ns, T\(^\ast_{1\text{,h}}\) \(\geq\) 30 ns), which remains stable over multiple cycles of heating to the room temperature and cooling. In addition, elliptically polarized light induced an "optical" magnetic field on the system due to the AC Stark effect. It is confirmed using a new modification of polarization noise spectroscopy with a small degree of circular polarization of the probe light added with different frequencies.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 10 figures
From High-Entropy Alloys to Alloys with High Entropy: A New Paradigm in Materials Science and Engineering for Advancing Sustainable Metallurgy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Jose Manuel Torralba, Alberto Meza, S. Venkatesh Kumaran, Amir Mostafaei, Ahad Mohammadzadehd
The development of high-entropy alloys (HEAs) has marked a paradigm shift in alloy design, moving away from traditional methods that prioritize a dominant base metal enhanced by minor elements. HEAs instead incorporate multiple alloying elements with no single dominant component, broadening the scope of alloy design. This shift has led to the creation of diverse alloys with high entropy (AHEs) families, including high-entropy steels, superalloys, and intermetallics, each highlighting the need to consider additional factors such as stacking fault energy (SFE), lattice misfit, and anti-phase boundary energy (APBE) due to their significant influence on microstructure and performance. Leveraging multiple elements in alloying opens up promising possibilities for developing new alloys from multi-component scrap and electronic waste, reducing reliance on critical metals and emphasizing the need for advanced data generation techniques. With the vast possibilities offered by these multi-component feedstocks, modelling and Artificial Intelligence based tools are essential to efficiently explore and optimize new alloys, supporting sustainable progress in metallurgy. These advancements call for a reimagined alloy design framework, emphasizing robust data acquisition, alternative design parameters, and advanced computational tools over traditional composition-focused methodologies.
Materials Science (cond-mat.mtrl-sci)
Magnetic phase diagram of multiferroic and magnetocaloric TmFeO3
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
K. I. Tkachenko, P. Fabrykiewicz, A. K. Ovsianikov, M. Meven, O.V. Usmanov, I. A. Zobkalo, K.A. Shaykhutdinov, K. Yu Terentjev, E. Ressouche, K. Beauvois
Neutron diffraction experiments of TmFeO3 single crystals were performed in the external magnetic fields. The field along c-axis increases temperature of spin-reorientation transition TSR from phase {}4 to {}2. Application of the field along b-axis led to the decrease of TSR and to the formation of new phases. Based on the temperature and field dependence of the Bragg reflection intensity, the configuration of magnetically induced phases was proposed. The magneto-structural effects were observed.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other)
9 pages, 4 figures
Exploring the Interaction of BeS Monolayer and Lung Disease Biomarkers: Potential Material for Biosensing Applications
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Considerable attention has been directed towards the prognosis of lung diseases primarily due to their high prevalence. Despite advancements in detection technologies, current methods such as computed tomography, chest radiographs, bold proteomic patterns, nuclear magnetic resonance, and positron emission tomography still face limitations in detecting diseases related to the lungs. Consequently, there is a need for swift, non-invasive and economically feasible detection methods. Our study explores the interaction between BeS monolayer and breathe biomarkers related to lung disease utilizing the density functional theory (DFT) method. Through comprehensive DFT analysis, including electronic properties analysis, charge transfer evaluations, work function, optical properties assessment and recovery times, the feasibility and efficiency of BeS as a VOC (volatile organic compound) detection are investigated. Findings reveal significant changes in bandgap upon VOC adsorption, with notable alteration in work function for selective compounds. Optical property analyses demonstrate the potential for selective detection of biomarkers within specific wavelength ranges. Moreover, the study evaluates the impact of electric fields and strain on VOC-2D BeS interaction. Furthermore, the desorption of these VOCs from the BeS surface can be achieved through a heating process or under the illumination of UV light. This feature enables the reusability of the 2D material for biosensing applications. These findings highlight the potential of the BeS monolayer as a promising material for the sensitive and selective detection of breath biomarkers related to lung disease.
Materials Science (cond-mat.mtrl-sci)
Metal-organic chemical vapor deposition of MgSiN\(_{2}\) thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Vijay Gopal Thirupakuzi Vangipuram, Chenxi Hu, Abdul Mukit Majumder, Christopher Chae, Kaitian Zhang, Jinwoo Hwang, Kathleen Kash, Hongping Zhao
Orthorhombic-structured II-IV nitrides provide a promising opportunity to expand the material platform while maintaining compatibility with the wurtzite crystal structure of the traditional III-nitride material system. Among them, MgSiN\(_{2}\) stands out due to its close compatibility with GaN and AlN and its theoretically predicted ultrawide direct band gap of 6.28 eV. In this work, the growth of MgSiN\(_{2}\) thin films on GaN-on-sapphire and c-plane sapphire substrates was investigated using metal-organic chemical vapor deposition (MOCVD). MOCVD growth conditions were correlated with film quality and crystallinity for samples grown on GaN-on-sapphire substrates. The effects of Mg:Si precursor molar flow rate ratios and growth pressure at two different temperatures, 745\(^{\circ}\)C and 850\(^{\circ}\)C, were studied comprehensively. High-resolution scanning transmission electron microscopy (STEM) imaging confirmed the formation of high-quality, single-crystal MgSiN\(_{2}\) films. Optical band gap extraction from transmittance measurements yielded direct band gap values ranging from 6.13 eV to 6.27 eV for samples grown under various conditions, confirming the realization of an ultrawide-band gap, III-nitride-compatible, II-IV-nitride material.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Photoluminescence efficiency of MBE-grown MoSe\(_2\) monolayers featuring sharp excitonic lines and diverse grain structures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Mateusz Raczyński, Julia Kucharek, Kacper Oreszczuk, Aleksander Rodek, Tomasz Kazimierczuk, Rafał Bożek, Takashi Taniguchi, Kenji Watanabe, Wojciech Pacuski, Piotr Kossacki
Recent studies have demonstrated that using h-BN as a substrate for the growth of transition metal dichalcogenides can significantly reduce excitonic linewidths. However, many other optical parameters still require optimization. In this work, we present a detailed study of the low-temperature photoluminescence efficiency of MBE-grown MoSe\(_2\) monolayers on h-BN substrates, comparing them to state-of-the-art exfoliated monolayers encapsulated in h-BN. We demonstrate that a quantitative comparison between samples requires accounting for interference effects and Purcell enhancement or suppression of the emission. By accounting for these effects in both photoluminescence and Raman signals, we show that the overall intrinsic luminescence efficiency is proportional to the sample coverage. Consequently, we find that exciton diffusion and edge effects are negligible in spectroscopy of MBE-grown samples, even for nanometer-sized crystals.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 9 figures
Fractional topological states in rhombohedral multilayer graphene modulated by kagome superlattice
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-25 20:00 EST
Yanran Shi, Bo Xie, Fengfan Ren, Xinyu Cai, Zhongqing Guo, Qiao Li, Xin Lu, Zhongkai Liu, Jianpeng Liu
Fractional quantum anomalous Hall effects realized in twisted bilayer MoTe\(_2\) and multilayer-graphene-based moiré heterostructures have captured a tremendous growth of interest. In this work, we propose that rhombohedral multilayer graphene coupled with an artificial kagome superlattice potential is a new platform to realize various fractional topological phases. Taking Bernal bilayer graphene as the simplest example, when it is placed on top of a prepatterned SiO\(_2\) substrate with periodic arrays of holes arranged into kagome lattice, the system would be subject to a tunable kagome superlattice potential once an electrostatic voltage drop between the top and bottom gates is applied. Then, we theoretically study the electronic band structures, topological properties, and quantum geometric properties of the Bloch states of Bernal bilayer graphene coupled with a realistic kagome superlattice potential, which is benchmarked by transport measurements in the weak superlattice-potential and large filling factor regime. We find that the system may exhibit nearly ideal topological flat bands in a substantial region of the parameter space spanned by superlattice constant and electrostatic potential strength. When these topological flat bands are fractionally filled, exact diagonalization calculations suggest that the system would exhibit rich fractional topological phases at 1/3, 2/3, 2/5, 3/5 and 1/2 fillings including both fractional Chern insulators and anomalous composite Fermi liquids under zero magnetic field.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
5 pages main text, 15 pages Supplemental Materials
Electronic and Structural Properties of Lanthanide-Doped MoS\(_2\): Impact of Ionic Size and Orbital Configuration Mismatch
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Hyosik Kang, Raquel Queiroz, Lukas Muechler
Single-photon emitters (SPEs) are crucial for quantum technologies such as quantum simulation, secure quantum communication, and precision measurements. Two-dimensional transition metal dichalcogenides (TMDCs) are promising SPE candidates due to their atomically thin nature and efficient photon extraction. However, their emission wavelengths limit compatibility with existing telecommunication technologies. Lanthanide doping in TMDCs, such as , offers a potential solution by introducing sharp, \(f\)-orbital derived emissions in the infrared range. Yet, the feasibility of introducing these dopants remains uncertain due to their large ionic radii of the lanthanides. We employ density functional theory (DFT) calculations to investigate the structural and electronic properties of lanthanide-doped monolayers (Ln=Ce, Er). By evaluating formation energies with up to three adjacent S vacancies, we assess how these vacancies mitigate lattice strain caused by the size mismatch of Ce and Er with Mo. Our results show that while destabilizes the pristine lattice, S vacancies enhance thermodynamic stability. Charge state analysis indicates that defect states introduced by localize near the valence band and remain stable across a wide Fermi energy range. Electronic structure analysis shows that Ce\(^{4+}\) and Er\(^{3+}\) maintain their oxidation states upon electron doping due to additional acceptor states from host-induced dangling bonds. These states arise from an orbital filling mismatch between dopants and Mo. Consequently, is unlikely to exhibit infrared emissions due to its empty \(f\)-shell, whereas is expected to emit in the infrared. These findings demonstrate the potential of lanthanide-doped TMDCs as tunable SPEs and provide design strategies for optimizing their optical and electronic properties.
Materials Science (cond-mat.mtrl-sci)
An Explainable AI Model for Binary LJ Fluids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-25 20:00 EST
Israrul H Hashmi, Rahul Karmakar, Marripelli Maniteja, Kumar Ayush, Tarak K. Patra
Lennard-Jones (LJ) fluids serve as an important theoretical framework for understanding molecular interactions. Binary LJ fluids, where two distinct species of particles interact based on the LJ potential, exhibit rich phase behavior and provide valuable insights of complex fluid mixtures. Here we report the construction and utility of an artificial intelligence (AI) model for binary LJ fluids, focusing on their effectiveness in predicting radial distribution functions (RDFs) across a range of conditions. The RDFs of a binary mixture with varying compositions and temperatures are collected from molecular dynamics (MD) simulations to establish and validate the AI model. In this AI pipeline, RDFs are discretized in order to reduce the output dimension of the model. This, in turn, improves the efficacy, and reduce the complexity of an AI RDF model. The model is shown to predict RDFs for many unknown mixtures very accurately, especially outside the training temperature range. Our analysis suggests that the particle size ratio has a higher order impact on the microstructure of a binary mixture. We also highlight the areas where the fidelity of the AI model is low when encountering new regimes with different underlying physics.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG), Chemical Physics (physics.chem-ph)
Ancilla theory of twisted bilayer graphene I: topological Mott semimetal and symmetric pseudogap metal
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-25 20:00 EST
Jing-Yu Zhao, Boran Zhou, Ya-Hui Zhang
In this work, we demonstrate that Mott physics in twisted bilayer graphene (TBG) can be conveniently captured using the ancilla theory, originally proposed in the context of high-Tc cuprates [Zhang and Sachdev, Phys. Rev. Res. 2, 023172 (2020)]. In this framework, the Mott gap emerges as a band gap controlled by a hybridization order parameter \(\Phi(\mathbf k)\) between the physical and ancilla bands. In TBG, the ancilla formalism allows us to calculate the upper and lower Hubbard bands directly in momentum space, both at and away from the magic angle. Projected to the active bands, we reveal a topological obstruction for \(\Phi(\mathbf k)\) around the \(\Gamma\) point, leading to a topological Mott semi-metal at \(\nu=0\). At fillings \(\nu=\pm 1, \pm 2, \pm 3\), we obtain symmetric correlated insulators at large \(U\), and also transitions to semi-metals at smaller \(U\) or larger bandwidth. The new formalism also enables us to study the most intriguing density range, \(\nu=-2-x\): we propose a symmetric pseudogap metal at small \(x\), which hosts a small Fermi surface and violates the perturbative Luttinger theorem. Our theory works above the ordering temperature of a potential symmetry-breaking order. Alternatively, the symmetric pseudogap metal can survive to the zero-temperature limit when there is a sizable anti-Hund's coupling \(J_A\). In our theory, the small Fermi surface of the pseudogap metal is primarily formed by ancilla fermions, which we interpret as composite polarons-consisting of a spin moment on an AA site bound to a hole in the nearest neighbor AA site. Within the active band subspace, the composite polaron at \(\mathbf k=0\) is orthogonal to the single-particle state due to their differing angular momenta, and thus has vanishing spectral weight. We suggest that superconductivity emerges from the Cooper pairing of these composite fermions instead of single electrons.
Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 19 figures, 3 tables