CMP Journal 2025-01-10
Statistics
Science: 4
arXiv: 74
Science
Local genetic adaptation to habitat in wild chimpanzees
Research Article | Evolution | 2025-01-10 03:00 EST
Harrison J. Ostridge, Claudia Fontsere, Esther Lizano, Daniela C. Soto, Joshua M. Schmidt, Vrishti Saxena, Marina Alvarez-Estape, Christopher D. Barratt, Paolo Gratton, Gaëlle Bocksberger, Jack D. Lester, Paula Dieguez, Anthony Agbor, Samuel Angedakin, Alfred Kwabena Assumang, Emma Bailey, Donatienne Barubiyo, Mattia Bessone, Gregory Brazzola, Rebecca Chancellor, Heather Cohen, ` Coupland, Emmanuel Danquah, Tobias Deschner, Laia Dotras, Jef Dupain, Villard Ebot Egbe, Anne-Céline Granjon, Josephine Head, Daniela Hedwig, Veerle Hermans, R. Adriana Hernandez-Aguilar, Kathryn J. Jeffery, Sorrel Jones, Jessica Junker, Parag Kadam, Michael Kaiser, Ammie K. Kalan, Mbangi Kambere, Ivonne Kienast, Deo Kujirakwinja, Kevin E. Langergraber, Juan Lapuente, Bradley Larson, Anne Laudisoit, Kevin C. Lee, Manuel Llana, Giovanna Maretti, Rumen Martín, Amelia C. Meier, David Morgan, Emily Neil, Sonia Nicholl, Stuart Nixon, Emmanuelle Normand, Christopher Orbell, Lucy Jayne Ormsby, Robinson Orume, Liliana Pacheco, Jodie Preece, Sebastien Regnaut, Martha M. Robbins, Aaron Rundus, Crickette Sanz, Lilah Sciaky, Volker Sommer, Fiona A. Stewart, Nikki Tagg, Luc Roscelin Tédonzong, Joost van Schijndel, Elleni Vendras, Erin G. Wessling, Jacob Willie, Roman M. Wittig, Yisa Ginath Yuh, Kyle Yurkiw, Linda Vigilant, Alex K. Piel, Christophe Boesch, Hjalmar S. Kühl, Megan Y. Dennis, Tomas Marques-Bonet, Mimi Arandjelovic, Aida M. Andrés
Adaptation to different environments can include responding to a myriad of pressures, from diseases to differences in water abundance. Of the great apes, chimpanzees are most similar to humans in that they inhabit a range of environments from savannahs to rainforests. Ostridge et al. sequenced exomes from 388 chimpanzees using fecal samples to investigate how selection has acted on these animals. Signatures of selection differed by environment, with forest-dwelling chimpanzee populations bearing variants in genes associated with disease resistance. This study demonstrates the utility of environmentally collected DNA in an endangered species and provides insights into adaptation in our closest living relative. --Corinne Simonti
Decoding the molecular interplay of CD20 and therapeutic antibodies with fast volumetric nanoscopy
Research Article | Nanoscopic imaging | 2025-01-10 03:00 EST
Arindam Ghosh, Mara Meub, Dominic A. Helmerich, Julia Weingart, Patrick Eiring, Thomas Nerreter, K. Martin Kortüm, Sören Doose, Markus Sauer
Therapeutic monoclonal antibodies (mAbs) are used in chronic lymphocytic leukemia immunotherapies to target the receptor CD20 at the plasma membrane of immunological B cells. Although they have been in clinical use for several years, the molecular binding mechanisms of mAbs to endogenous CD20 are unclear, as is how antibody binding activates the immune system to kill B cells. Ghosh et al. developed a method for fast volumetric fluorescence imaging with high spatiotemporal resolution that reveals the accumulation of CD20/mAb complexes on the microvilli of polarized B cells. The results show that the classification criterion of anti-CD20 mAbs based on their receptor cross-linking efficiency needs revision. Such high-end imaging techniques should help in the development of improved immunotherapies. --Stella M. Hurtley
Sexually dimorphic dopaminergic circuits determine sex preference
Research Article | Neuroscience | 2025-01-10 03:00 EST
Anqi Wei, Anran Zhao, Chaowen Zheng, Nan Dong, Xu Cheng, Xueting Duan, Shuaijie Zhong, Xiaoying Liu, Jie Jian, Yuhao Qin, Yuxin Yang, Yuhao Gu, Bianbian Wang, Niki Gooya, Jingxiao Huo, Jingyu Yao, Weiwei Li, Kai Huang, Haiyao Liu, Fenghan Mao, Ruolin Wang, Mingjie Shao, Botao Wang, Yichi Zhang, Yang Chen, Qian Song, Rong Huang, Qiumin Qu, Chunxiang Zhang, Xinjiang Kang, Huadong Xu, Changhe Wang
Social interactions shape our everyday lives. Innate preference for social interaction with male or female conspecifics is a critical component in determining survival and reproduction success. Wei et al. studied same versus opposite sex social interaction in mice, showing that both male and female animals exhibit female social preference in normal conditions but switch to male preference when under survival threat (see the Perspective by Joo and Tye). The switch is mediated by activation of specific populations of dopaminergic neurons in the ventral tegmental area (VTA) of the brain. The results identify sex-specific VTA-mediated neuronal circuits critical for determining sex preference. --Mattia Maroso
Superstable lipid vacuoles endow cartilage with its shape and biomechanics
Research Article | Cell biology | 2025-01-10 03:00 EST
Raul Ramos, Kim T. Pham, Richard C. Prince, Leith B. Leiser-Miller, Maneeshi S. Prasad, Xiaojie Wang, Rachel C. Nordberg, Benjamin J. Bielajew, Jerry C. Hu, Kosuke Yamaga, Ji Won Oh, Tao Peng, Rupsa Datta, Aksana Astrowskaja, Axel A. Almet, John T. Burns, Yuchen Liu, Christian Fernando Guerrero-Juarez, Bryant Q. Tran, Yi-Lin Chu, Anh M. Nguyen, Tsai-Ching Hsi, Norman T.-L. Lim, Sandra Schoeniger, Ruiqi Liu, Yun-Ling Pai, Chella K. Vadivel, Sandy Ingleby, Andrew E. McKechnie, Frank van Breukelen, Kyle L. Hoehn, John J. Rasweiler, Michinori Kohara, William J. Loughry, Scott H. Weldy, Raymond Cosper, Chao-Chun Yang, Sung-Jan Lin, Kimberly L. Cooper, Sharlene E. Santana, Jeffrey E. Bradley, Michael A. Kiebish, Michelle Digman, David E. James, Amy E. Merrill, Qing Nie, Thomas F. Schilling, Aliaksandr A. Astrowski, Eric O. Potma, Martín I. García-Castro, Kyriacos A. Athanasiou, Richard R. Behringer, Maksim V. Plikus
Cartilage is considered to be a mostly cell-free tissue made of copious extracellular matrix. Ramos et al. describe the embryonic development, gene expression, biochemistry, physiology, and biomechanics of lipid-filled cartilage in mice (see the Perspective by Hermosilla Aguayo and Selleri). This "fatty cartilage" forms from lipochondrocytes found in the face, neck, and chest of phylogenetically diverse mammals. It can adopt intricately patterned shapes and has life-long stability and elastic properties because of its large lipid vacuoles within numerous long-lived cells having little extracellular matrix. These findings hold promise for advancing our understanding of form-to-function relationships in skeletal tissues. --Stella M. Hurtley
arXiv
Dirac-Schwinger Quantization for Emergent Magnetic Monopoles?
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
A. Farhan (1), M. Saccone (2), B.F.L. Ward (1) ((1) Baylor University, Waco, TX, USA, (2) Croputation, Santa Fe, NM, USA)
In Refs.[1-4] Dirac and Schwinger showed the existence of a magnetic monopole required a charge quantization condition which we write following Dirac as \(\frac{eg}{4\pi\hbar}=\frac{n}{2},\; n=0,\pm 1,\; \pm 2, \ldots\). Here, \(g\) is the magnetic monopole charge and \(e\) is the electric charge of the positron. Recently, in Refs. [5,6], it has been shown experimentally that frustrated spin-ice systems exhibit 'emergent' magnetic monopoles. We show that, within the experimental errors, the respective magnetic charges obey the Dirac-Schwinger quantization condition. Possible implications are discussed.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Phenomenology (hep-ph)
4 pages, no figures
The effects of Repulsive Biquadratic Interactions in a Blume-Emery-Griffiths Spin-Glass with Competing, Attractive Biquadratic Cross-link Interactions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-10 20:00 EST
A BEG Hamiltonian is used to model an Ising spin glass with annealed vacancies on a hierarchical lattice. In addition to competing bilinear interactions, repulsive biquadratic interactions on the perimeter of our unit structures compete with attractive cross-link interactions. Ordering and transitions in this system are probed by generating several phase diagrams, using renormalization group methods, for a range of constant K/J. A physical interpretation is offered for each sink corresponding to a bulk phase in phase space and critical exponents are calculated for the higher-order transitions.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 8 figures. arXiv admin note: text overlap with arXiv:0902.1971
Topological quantized edge-pumping-spin flip in Rice-Mele model with spin-orbit coupling
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
The quantized Thouless pumping charge in a spinless Rice-Mele (RM) model originates from a degeneracy point in the parameter space and cannot be detected when open boundary conditions are applied. In this work, we investigate the topological features of a spinful Rice-Mele (RM) model. We demonstrate that spin-orbit coupling facilitates the transition of a single degenerate point into a degenerate loop, which is anticipated to be the source of the topological characteristics. When periodic boundary conditions are considered, we find that the pumping spin is zero for an adiabatic loop within the nodal loop and is 2 (in units of \(\hbar /2\)) for an adiabatic passage enclosing the nodal loop. When open boundary conditions are considered, the boundary-bulk correspondence is demonstrated by quantized pumping-spin flips at the edges, which can be obtained by completing double periods of a closed passage, rather than a single cycle. Our findings reveal an alternative dynamic manifestation of the boundary-bulk correspondence.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
Probing the collective excitations of excitonic insulators in an optical cavity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
The light--matter interaction in optical cavities offers a promising ground to create hybrid states and manipulate material properties. In this work, we examine the effect of light-matter coupling in the excitonic insulator phase using a quasi one-dimensional lattice model with two opposite parity orbitals at each site. We show that the model allows for a coupling between the collective phase mode and cavity photons. Our findings reveal that the collective mode of the excitonic state significantly impacts the dispersion of the cavity mode, giving rise to an avoiding band crossing in the photon dispersion. This phenomenon is absent in trivial and topological insulator phases and also in phonon-mediated excitonic insulators, underscoring the unique characteristics of collective excitations in excitonic insulators. Our results demonstrate the significant impact of light-matter interaction on photon propagation in the presence of excitonic collective excitations.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 3 figures
Resonant X-ray spectroscopies on Chromium 3 orbitals in CrSBr
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Victor Porée, Alberto Zobelli, Amit Pawbake, Jakub Regner, Zdenek Sofer, Clément Faugeras, Alessandro Nicolaou
We investigate the Cr electronic structure and excitations in CrSBr, a layered magnetic semiconductor, using a combination of resonant x-ray spectroscopic techniques. X-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) spectra collected at the Cr \(L_{2,3}\) edges reveal significant linear dichroism, which arises from the distorted octahedral environment surrounding the Cr\(^{3+}\) ions. The origin of the bright excitons observed in this compound is examined through a comparison of the d-d excitations identified in the RIXS spectra, the x-ray excited optical luminescence (XEOL) spectra, and previously reported optical spectroscopic and theoretical studies. To further understand these phenomena, we develop a multiplet model based on a crystal electric field (CEF) approach that accounts for the local environment of Cr ions. This model successfully reproduces several experimental features, while also suggesting strong hybridization effects between Cr 3 orbitals and ligands that are not fully captured by the present framework. These findings advance our understanding of the electronic structure and excitonic behavior in CrSBr and provide a foundation for future \(\textit{in-situ}\) and \(\textit{operando}\) studies of CrSBr-based devices for spintronic and optoelectronic applications.
Materials Science (cond-mat.mtrl-sci)
10 pages, 10 figures
Role of asymmetry in thermoelectric properties of a double quantum dot out of equilibrium
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Diego Perez Daroca, Pablo Roura-Bas, Armando A. Aligia
We investigate the thermoelectric properties of a double quantum dot system coupled to two metallic reservoirs, focusing on two main effects: (i) the influence of coupling asymmetry between the quantum dot and the reservoirs on the Seebeck coefficient, and (ii) the impact of asymmetry in the energy levels of the dots on current rectification. In the first case, we find that introducing moderate asymmetry significantly enhances the Seebeck coefficient. In the second case, while rectification vanishes when the energy levels are degenerate, substantial rectification is achieved when one energy level lies below and the other above the Fermi level. We further interpret the dependence of rectification magnitude and shape on system parameters using analytical results from a spinless model.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 6 figures, accepted in Phys. Rev. B
Microscopic structure and dynamics of shear-thinning suspensions of polydisperse, repulsive vesicles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Nikolaos Kolezakis, Stefano Aime, Raffaele Pastore, Vincenzo Guida, Gaetano D Avino, Paolo Edera
We investigate the rheology, microscopic structure, and dynamics of an industrially relevant dispersion made of cationic surfactant vesicles, from dilute to concentrated conditions. We find that these suspensions exhibit a shear-thinning behavior at relatively low concentrations. At the microscale, this corresponds to a well-defined transition in both the structure, marked by the appearance of a peak in the static structure factor, and the dynamics, which slow down and develop a two-step decay in the correlation functions. This low-concentration transition is particularly surprising in light of experiments showing that for surfactant vesicles of similar composition the interactions should be purely repulsive. This leads us to propose that the observed structural and dynamic transition could arise, as an entropic effect, from the large sample polydispersity coupled to crowding. The shear-thinning behavior is thus interpreted as the nonlinear response of this transient structure to the imposed flow. Our work suggests that similar effects might be a generic feature of dense, highly polydisperse charged suspensions.
Soft Condensed Matter (cond-mat.soft)
14 Pages with appendix. 6 figures in the main text + 10 figures in the appendix
Phase diagram, confining strings, and a new universality class in nematopolar matter
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Farzan Vafa, Amin Doostmohammadi
We study a minimal model of a system with coexisting nematic and polar orientational orders, where one field tends to order and the other prefers isotropy. For strong coupling, the ordered field aligns the isotropic one, locking their orientations. The phase diagram reveals three distinct phases--nematopolar (aligned orders), nematic (independent orders), and isotropic (vanishing orders)--separated by continuous and discontinuous transitions, including a triple and a tricritical point. We find unique critical scaling for the nematopolar-nematic transition, distinct from standard nematic or polar universality classes. Additionally, in the locked nematopolar phase, we show nematic \(+1/2\) topological defect pairs are connected and confined by strings with constant tension. These strings arise from frustration in locking the orientational orders and can be interpreted as elongated cores of \(+1\) polar topological defects. When a sufficiently strong background field couples to the polar order, all topological defects are expelled from the region. Analytical predictions are quantitatively confirmed by numerical simulations.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
6 + 8 pages, 4 + 1 figures, 1 table
Spectroscopy of the Fractal Hofstadter Energy Spectrum
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Kevin P. Nuckolls, Michael G. Scheer, Dillon Wong, Myungchul Oh, Ryan L. Lee, Jonah Herzog-Arbeitman, Kenji Watanabe, Takashi Taniguchi, Biao Lian, Ali Yazdani
Hofstadter's butterfly, the predicted energy spectrum for non-interacting electrons confined to a two-dimensional lattice in a magnetic field, is one of the most remarkable fractal structures in nature. At rational ratios of magnetic flux quanta per lattice unit cell, this spectrum shows self-similar distributions of energy levels that reflect its recursive construction. For most materials, Hofstadter's butterfly is predicted under experimental conditions that are unachievable using laboratory-scale magnetic fields. More recently, electrical transport studies have provided evidence for Hofstadter's butterfly in materials engineered to have artificially large lattice constants, such as those with moiré superlattices. Yet to-date, direct spectroscopy of the fractal energy spectrum predicted by Hofstadter nearly 50 years ago has remained out of reach. Here we use high-resolution scanning tunneling microscopy / spectroscopy (STM / STS) to probe the flat electronic bands in twisted bilayer graphene near the predicted second magic angle, an ideal setting for spectroscopic studies of Hofstadter's spectrum. Our study shows the fractionalization of flat moiré bands into discrete Hofstadter subbands and discerns experimental signatures of self-similarity of this spectrum. Moreover, our measurements uncover a spectrum that evolves dynamically with electron density, displaying phenomena beyond that of Hofstadter's original model due to the combined effects of strong correlations, Coulomb interactions, and the quantum degeneracy of electrons in twisted bilayer graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Strongly Correlated Electrons (cond-mat.str-el)
20 pages, 5 figures
A phase-field model for DNA self-assembly
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Marco Cappa, Francesco Sciortino, Lorenzo Rovigatti
We present a phase-field model based on the Cahn-Hilliard equation to investigate the kinetics of phase separation in DNA nanostar systems. Leveraging a realistic free-energy functional derived from Wertheim theory, our model captures the thermodynamic and dynamic properties of self-assembling DNA nanostars under various conditions. This approach allows for the study of both one-component and multi-component systems, including mixtures of different nanostar species and cross-linkers. Through numerical simulations, we demonstrate the model ability to replicate experimental observations, including liquid-liquid phase separation, surface tension variation, and the structural organization of multi-component systems. Our results highlight the versatility and predictive power of the Cahn-Hilliard framework, particularly for complex systems where detailed simulations are computationally prohibitive. This work provides a robust foundation for studying DNA-based materials and their potential applications in nanotechnology and biophysics, including liquid-liquid phase separation in cellular environments.
Soft Condensed Matter (cond-mat.soft)
10 pages, 5 figures
Phase Transitions in Quasi-Periodically Driven Quantum Critical Systems: Analytical Results
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-10 20:00 EST
Jiyuan Fang, Qi Zhou, Xueda Wen
In this work, we study analytically the phase transitions in quasi-periodically driven one dimensional quantum critical systems that are described by conformal field theories (CFTs). The phase diagrams and phase transitions can be analytically obtained by using Avila's global theory in one-frequency quasiperiodic cocycles. Compared to the previous works where the quasiperiodicity was introduced in the driving time and no phase transitions were observed [1], here we propose a setup where the quasiperiodicity is introduced in the driving Hamiltonians. In our setup, one can observe the heating phases, non-heating phases, and the phase transitions. The phase diagram as well as the Lyapunov exponents that determine the entanglement entropy evolution can be analytically obtained. In addition, based on Avila's theory, we prove there is no phase transition in the previously proposed setup of quasi-periodically driven CFTs [1]. We verify our field theory results by studying the time evolution of entanglement entropy on lattice models.
Statistical Mechanics (cond-mat.stat-mech), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
20 pages, many figures
Rotational magnetoelastic interactions in the Dzyaloshinskii-Moriya magnet Ba\(_2\)CuGe\(_2\)O\(_7\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
J. Sourd, T. Kotte, P. Wild, S. Mühlbauer, J. Wosnitza, S. Zherlitsyn
We report the magnetoelastic properties of a Ba\(_2\)CuGe\(_2\)O\(_7\) single crystal at low temperatures under a magnetic field applied along the crystallographic [001] axis. Our results extend to low temperature the \(H-T\) phase diagram determined for this compound by neutron scattering. Furthermore, we observe that specific elastic modes are better sensitive to the various magnetic transitions. In particular, we observe an unusual coupling between the in-plane transverse acoustic mode and the cycloidal order at low field, which suggests a novel spin-strain mechanism originating from Dzyaloshinskii-Moriya interaction in this compound.
Strongly Correlated Electrons (cond-mat.str-el)
Giant Kohn anomaly and chiral phonons in the charge density wave phase of 1H-NbSe\(_2\)
New Submission | Other Condensed Matter (cond-mat.other) | 2025-01-10 20:00 EST
Susy Exists, Sougata Mardanya, Robert Markiewicz, Tugrul Hakioglu, Jouko Nieminen, Ville J. Härkönen, Cem Sanga, Arun Bansil, Sugata Chowdhury
Despite extensive investigations, many aspects of charge density waves (CDWs) remain elusive, especially the relative roles of electron-phonon coupling and Fermi surface nesting as the underlying driving mechanisms responsible for the emergence of the CDW vector \(\bl Q_{CDW}\). It is puzzling that even though electrons interact strongly with optical phonons in many correlated systems, the actual mode softening is of an acoustic mode. Here we consider monolayer 1H-NbSe\(_2\) as an exemplar system, and through an accurate computation of the phonon self-energy, including its off-diagonal components. We provide compelling evidence that the relevant mode is a longitudinal optical phonon that softens by anti-crossing several intervening phonon bands. We also show that \(\bl Q_{CDW}\) is fixed by the convolution of the susceptibility and electron-phonon coupling, and that the softened phonons are circularly polarized.
Other Condensed Matter (cond-mat.other)
16 pages, 13 figures
Intrinsic Direct Air Capture
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Austin McDannald, Daniel W. Siderius, Brian DeCost, Kamal Choudhary, Diana L. Ortiz-Montalvo
We present new metrics to evaluate solid sorbent materials for Direct Air Capture (DAC). These new metrics provide a theoretical upper bound on CO2 captured per energy as well as a theoretical upper limit on the purity of the captured CO2. These new metrics are based entirely on intrinsic material properties and are therefore agnostic to the design of the DAC system. These metrics apply to any adsorption-refresh cycle design. In this work we demonstrate the use of these metrics with the example of temperature-pressure swing refresh cycles. The main requirement for applying these metrics is to describe the equilibrium uptake (along with a few other materials properties) of each species in terms of the thermodynamic variables (e.g. temperature, pressure). We derive these metrics from thermodynamic energy balances. To apply these metrics on a set of examples, we first generated approximations of the necessary materials properties for 11 660 metal-organic framework materials (MOFs). We find that the performance of the sorbents is highly dependent on the path through thermodynamic parameter space. These metrics allow for: 1) finding the optimum materials given a particular refresh cycle, and 2) finding the optimum refresh cycles given a particular sorbent. Applying these metrics to the database of MOFs lead to the following insights: 1) start cold - the equilibrium uptake of CO2 diverges from that of N2 at lower temperatures, and 2) selectivity of CO2 vs other gases at any one point in the cycle does not matter - what matters is the relative change in uptake along the cycle.
Materials Science (cond-mat.mtrl-sci)
Training Allostery-Inspired Mechanical Response in Disordered Elastic Networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Disordered elastic networks are a model material system in which it is possible to achieve tunable and trainable functions. This work investigates the modification of local mechanical properties in disordered networks inspired by allosteric interactions in proteins: applying strain locally to a set of source nodes triggers a strain response at a distant set of target nodes. This is demonstrated first by using directed aging to modify the existing mechanical coupling between pairs of distant source and target nodes, and later as a means for inducing coupling between formerly isolated source-target pairs. The experimental results are compared with those predicted by simulations.
Soft Condensed Matter (cond-mat.soft)
Direct measurement of the longitudinal exciton dispersion in hBN by resonant inelastic x-ray scattering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Alessandro Nicolaou, Kari Ruotsalainen, Laura Susana, Victor Porée, Luiz Galvao Tizei, Jaakko Koskelo, Takashi Taniguchi, Kenji Watanabe, Alberto Zobelli, Matteo Gatti
We report resonant inelastic X-ray scattering (RIXS) measurements on the prototypical hexagonal boron nitride hBN layered compound. The RIXS results at the B and N K edges have been combined with electron energy loss spectroscopy (EELS) experiments and ab initio calculations within the framework of the Bethe-Salpeter equation of many-body perturbation theory. By means of this tight interplay of different spectroscopies, the lowest longitudinal exciton of hBN has been identified. Moreover, its qualitatively different dispersions along the \(\Gamma\)K and the \(\Gamma\)M directions of the Brillouin zone have been determined. Our study advocates soft X-ray RIXS and EELS to be a promising combination to investigate electronic excitations in materials.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Finite-Size Effects in Aging can be Interpreted as Sub-Aging
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-10 20:00 EST
Henrik Christiansen, Suman Majumder, Wolfhard Janke, Malte Henkel
Systems brought out of equilibrium through a rapid quench from a disordered initial state into an ordered phase undergo physical aging in the form of phase-ordering kinetics, with characteristic dynamical scaling. In many systems, notably glasses, dynamical scaling is often described through sub-aging, where a phenomenological sub-aging exponent \(0<\mu< 1\) is empirically chosen to achieve the best possible data collapse. Here it is shown that finite-size effects modify the dynamical scaling behavior, away from simple aging with \(\mu=1\) towards \(\mu<1\), such that phenomenologically it would appear as sub-aging. This is exemplified for the exactly solved dynamical spherical model in dimensions \(2<d<4\) and numerical simulations of the two-dimensional Ising model, with short-ranged and long-ranged interactions.
Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
Time Symmetries of Quantum Memory Improve Thermodynamic Efficiency
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-10 20:00 EST
Alexander B. Boyd, Paul M. Riechers
Classical computations inherently require energy dissipation that increases significantly as the reliability of the computation improves. This dissipation arises when transitions between memory states are not balanced by their time-reversed counterparts. While classical memories exhibit a discrete set of possible time-reversal symmetries, quantum memory offers a continuum. This continuum enables the design of quantum memories that minimize irreversibility. As a result, quantum memory reduces energy dissipation several orders of magnitude below classical memory.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
Quantifying and Visualizing the Microscopic Degrees of Freedom of Grain Boundaries in the Wigner-Seitz Cell of the Displacement-Shift-Complete Lattice
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
We introduce a grain boundary (GB) translation vector, \(\textbf{t}^{WS}\), to describe and quantify the domain of the microscopic degrees of freedom of GBs. It has long been recognized that for fixed macroscopic degrees of freedom of a GB there exists a large multiplicity of states characterized by different relative grain translations. More recently another degree of freedom, \([n]\), the number of GB atoms, has emerged and is now recognized as an equally important component of GB structural multiplicity. In this work, we show that all GB microstates can be uniquely characterized by their value of \(\textbf{t}^{WS}\), which is located within the Wigner-Seitz (WS) cell of the Displacement-Shift-Complete lattice (DSCL) of the GB. The GB translation vector captures information about both the translation state and the number of GB atoms. We show that the density of GB microstates inside the cell of the DSCL is not uniform and can form clusters that correspond to different GB phases. The vectors connecting the centers of the clusters correspond to the Burgers vectors of GB phase junctions, which can be predicted without building the junctions. Using \(\textbf{t}^{WS}\), we quantify GB excess shear and argue that it is defined up to a DSCL vector, which has implications for thermodynamic equilibrium conditions. Additionally, this work generalizes the definition of the number of GB atoms \([n]\) to asymmetric boundaries.
Materials Science (cond-mat.mtrl-sci)
Energy filtering-induced ultrahigh thermoelectric power factors in Ni\(_3\)Ge
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Fabian Garmroudi, Simone Di Cataldo, Michael Parzer, Jennifer Coulter, Yutaka Iwasaki, Matthias Grasser, Simon Stockinger, Stephan Pázmán, Sandra Witzmann, Alexander Riss, Herwig Michor, Raimund Podloucky, Sergii Khmelevskyi, Antoine Georges, Karsten Held, Takao Mori, Ernst Bauer, Andrej Pustogow
Traditional thermoelectric materials rely on low thermal conductivity to enhance their efficiency but suffer from inherently limited power factors. Novel pathways to optimize electronic transport are thus crucial. Here, we achieve ultrahigh power factors in Ni\(_3\)Ge through a new materials design principle. When overlapping flat and dispersive bands are engineered to the Fermi level, charge carriers can undergo intense interband scattering, yielding an energy filtering effect similar to what has long been predicted in certain nanostructured materials. Via a multi-step DFT-based screening method developed herein, we discover a new family of L1\(_2\)-ordered binary compounds with ultrahigh power factors up to 11 mW m\(^{-1}\) K\(^{-2}\) near room temperature, which are driven by an intrinsic phonon-mediated energy filtering mechanism. Our comprehensive experimental and theoretical study of these new intriguing materials paves the way for understanding and designing high-performance scattering-tuned metallic thermoelectrics.
Materials Science (cond-mat.mtrl-sci)
Lifshitz transition and triplet \(p\)-wave pairing from the induced ferromagnetic plaquette via spin differentiated nonlocal interaction
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Rayan Farid, Daria Gazizova, B. D. E. McNiven, J. P. F. LeBlanc
We study the two-dimensional extended Hubbard model on a square lattice and incorporate spin-differentiated nearest neighbor (NN) interactions where the equal-spin (\(V_{uu}\)) and unequal-spin (\(V_{ud}\)) terms are independently tuned parameters. We compute single-particle excitations as well as static spin and pairing susceptibilities perturbatively up to the fourth order within the thermodynamic limit and at a finite fixed temperature. By explicitly encoding a ferromagnetic-like NN interaction (\(V_{uu} < V_{ud}\)), we induce a competition among the uniform \(q = (0,0)\), collinear \(q = (\pi,0)\), and staggered \(q = (\pi,\pi)\) spin excitations. This results in the formation of short-ranged \(2\times 2\) ferromagnetic plaquettes arranged in staggered or striped patterns. Kinetic frustration in hopping, both within and between these plaquettes, manifests in single-particle properties, resulting in a reduction of bandwidth and ultimately triggering a Lifshitz transition to quasi-one-dimensional bands. Furthermore, an attractive effective interaction within the localized ferromagnetic plaquette results in the emergence of equal-spin triplet \(p\)-wave pairing. We demonstrate that sufficiently strong magnetic fluctuations, even at finite length scales, can significantly influence single-particle and pairing properties without breaking translational symmetry. Our approach provides a novel pathway to realize a variety of rich magnetic phases and Fermi surface reconstruction driven by interactions in the absence of explicit geometric frustration.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
10 pages, 9 figures
Stability of a passive viscous droplet in a confined active nematic liquid crystal
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Tanumoy Dhar, Michael J. Shelley, David Saintillan
The translation and shape deformations of a passive viscous Newtonian droplet immersed in an active nematic liquid crystal under circular confinement are analyzed using a linear stability analysis. We focus on the case of a sharply aligned active nematic in the limit of strong elastic relaxation in two dimensions. Using an active liquid crystal model, we employ the Lorentz reciprocal theorem for Stokes flow to study the growth of interfacial perturbations as a result of both active and elastic stresses. Instabilities are uncovered in both extensile and contractile systems, for which growth rates are calculated and presented in terms of the dimensionless ratios of active, elastic, and capillary stresses, as well as the viscosity ratio between the two fluids. We also extend our theory to analyze the inverse scenario, namely, the stability of an active nematic droplet surrounded by a passive viscous layer. Our results highlight the subtle interplay of capillary, active, elastic, and viscous stresses in governing droplet stability. The instabilities uncovered here may be relevant to a plethora of biological active systems, from the dynamics of passive droplets in bacterial suspensions to the organization of subcellular compartments inside the cell and cell nucleus.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph), Fluid Dynamics (physics.flu-dyn)
A Cold Tracer in a Hot Bath: In and Out of Equilibrium
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-10 20:00 EST
Amer Al-Hiyasat, Sunghan Ro, Julien Tailleur
We study the dynamics of a zero-temperature overdamped tracer in a bath of Brownian particles. As the bath density is increased, the passive tracer transitions from an effectively active dynamics, characterized by boundary accumulation and ratchet currents, to a bona-fide equilibrium regime. To account for this, we eliminate the bath degrees of freedom under the assumption of linear coupling to the tracer and show convergence to equilibrium in the large density limit. We then develop a perturbation theory to characterize the tracer's departure from equilibrium at large but finite bath densities, revealing an intermediate time-reversible yet non-Boltzmann regime, followed by a fully irreversible one. Finally, we show that when the bath particles are connected as a lattice, mimicking a gel, the cold tracer drives the entire bath out of equilibrium, leading to a long-ranged suppression of bath fluctuations.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
6 pages, 4 figures
Adiabatic Pumping of Orbital Magnetization by Spin Precession
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Yafei Ren, Wenqin Chen, Chong Wang, Ting Cao, Di Xiao
We propose adiabatic pumping of orbital magnetization driven by coherent spin precession, facilitating the rectification of this precession. The orbital magnetization originates from the adiabatic evolution of valence electrons with a topological bulk contribution expressed as a Chern-Simons form. When the precession cone angle of spin \(\bm{S}\) is small, the resulting magnetization is proportional to \(\bm{S}\times \dot{\bm{S}}\), contributing to the magnon Zeeman effect. With a large cone angle, the magnetization can reach its natural unit, \(e/T\), in an antiferromagnetic topological insulator with \(e\) as the elementary charge and \(T\) as the precession period. This significant magnetization is related to the global properties of the electronic geometric phases in the parameter space spanned by \(\bm{S}\) and momentum \(\bm{k}\). When the pumped magnetization is inhomogeneous, induced by spin textures or electronic topological phase domains, a dissipationless charge current is also pumped. At last, we discuss the boundary contributions from the spin-driving edge states, which are intricately linked to the gauge-dependent quantum uncertainty of the Chern-Simons form.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 3 figures, comments are welcome
Charge sensing of few-electron ZnO double quantum dots probed by radio-frequency reflectometry
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Kosuke Noro, Motoya Shinozaki, Yusuke Kozuka, Kazuma Matsumura, Yoshihiro Fujiwara, Takeshi Kumasaka, Atsushi Tsukazaki, Masashi Kawasaki, Tomohiro Otsuka
Zinc oxide (ZnO) has garnered much attention as a promising material for quantum devices due to its unique characteristics. To utilize the potential of ZnO for quantum devices, the development of fundamental technological elements such as high-speed readout and charge sensing capabilities has become essential. In this study, we address these challenges by demonstrating radio-frequency (rf) reflectometry and charge sensing in ZnO quantum dots, thus advancing the potential for qubit applications. A device is fabricated on a high-quality ZnO heterostructure, featuring gate-defined target and sensor quantum dots. The sensor dot, integrated into an rf resonator circuit, enables the detection of single-electron charges in the target dots. Using this setup, the formation of few-electron double quantum dots is observed by obtaining their charge stability diagram. Also, a charge stability diagram with a gate pulse sequence is measured. We discuss the strong electron correlation in ZnO, which leads to nearly degenerate spin-singlet and -triplet two-electron states in the (0, 2) charge state, and the perspectives on spin-state readout.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Universal Turbulent States of Miscible Two-Component Bose-Einstein Condensates
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-01-10 20:00 EST
We investigate turbulence in miscible two-component Bose-Einstein condensates confined in a box potential using the coupled Gross-Pitaevskii equations. Turbulence is driven by an oscillating force, causing the components to oscillate either in-phase (co-oscillating) or out-of-phase (counter-oscillating). A parameter measuring component separation (0 for overlap, 1 for full separation) reveals two turbulent states: coupled (the parameter \(\sim0\)) and decoupled (the parameter \(\sim0.5\)). Co-oscillating flows transition between these states at a critical interaction strength, while counter-oscillating flows consistently show the decoupled state. A probabilistic model predicts the decoupled state's parameter as \(\sqrt{4/\pi - 1} = 0.523\), consistent with simulations.
Quantum Gases (cond-mat.quant-gas)
8 pages, 6 figures
Non-Hermiticity enhanced topological immunity of one-dimensional \(p\)-wave superconducting chain
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-10 20:00 EST
Min Liu, Yue Zhang, Rui Tian, Xiayao He, Tianhao Wu, Maksims Arzamasovs, Shuai Li, Bo Liu
Studying the immunity of topological superconductors against non-local disorder is one of the key issues in both fundamental researches and potential applications. Here, we demonstrate that the non-Hermiticity can enhance the robustness of topological edge states against non-local disorder. To illustrate that, we consider a one-dimensional (1D) generalized Kitaev model with the asymmetric hopping in the presence of disorder. It is shown that the region supporting Majorana zero modes (MZMs) against non-local disorder will be enlarged by the non-Hermiticity. Through both the numerical and analytical analyses, we show that non-Hermiticity can stabilize the topological superconducting (SC) phase against higher disorder strength. Our studies would offer new insights into the interplay between non-Hermiticity and topology.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
Microscopic origin of magnetoferroelectricity in monolayer NiBr\(_{2}\) and NiI\(_{2}\)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Hui-Shi Yu, Xiao-Sheng Ni, Dao-Xin Yao, Kun Cao
We investigate the magnetoelectric properties of the monolayer NiX\(_{2}\) (X = Br, I) through first-principles calculations. Our calculations predict that the NiBr\(_{2}\) monolayer exhibits a cycloidal magnetic ground state. For the NiI\(_{2}\) monolayer, a proper-screw helical magnetic ground state with modulation vector ( = (q, 0, 0)) is adopted, approximated based on experimental observations. The electric polarization in NiBr\(_{2}\) shows a linear dependence on the spin-orbit coupling strength ({}), which can be adequately described by the generalized Katsura-Nagaosa-Balatsky (gKNB) model, considering contributions from up to the third nearest-neighbor spin pairs. In contrast, the electric polarization in NiI\(_{2}\) exhibits a distinct dependence on (q) and ({}), which cannot be fully explained by the gKNB mechanism alone. To address this, the (p)-(d) hybridization mechanism is extended to NiI\(_{2}\) to explain the observed behavior. The respective contributions from the (p)-(d) hybridization and the gKNB mechanism in NiI\(_{2}\) are then quantitatively evaluated. Overall, our work elucidates the microscopic mechanisms underlying multiferroicity in NiBr\(_{2}\) and NiI\(_{2}\) monolayers, with the conclusions readily applicable to their bulk forms.
Materials Science (cond-mat.mtrl-sci)
Time-domain study of coupled collective excitations in quantum materials
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Quantum materials hold immense promises for future applications due to their intriguing electronic, magnetic, thermal, and mechanical properties that are often traced to a complex interplay among different microscopic degrees of freedom. Important insights of such interactions come from studying the collective excitations of electrons, spins, orbitals, and lattice, whose cooperative motions play a crucial role in determining the novel behavior of these systems and offer us a key tuning knob to modify material properties on-demand through external perturbations. In this regard, ultrafast light-matter interaction has shown great potential in controlling the couplings of collective excitations, and rapid progress in a plethora of time-resolved techniques down to the attosecond regime has significantly advanced our understanding of the coupling mechanism and guided us in manipulating the dynamical property of quantum materials. This review aims to highlight recent experiments on visualizing collective excitations in the time domain, focusing on the coupling mechanism between different collective modes such as phonon-phonon, phonon-magnon, phonon-exciton, magnon-magnon, magnon-exciton, and various polaritons. We introduce how these collective modes are excited by an ultrashort laser pulse and probed by different ultrafast techniques, and we explain how the coupling between collective excitations governs the ensuing nonequilibrium dynamics. We also provide some perspectives on future studies that can lead to further discoveries regarding the emergent properties of quantum materials both in and out of equilibrium.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Finite strain continuum phenomenological model describing the shape-memory effects in multi-phase semi-crystalline networks
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Matteo Arricca, Nicoletta Inverardi, Stefano Pandini, Maurizio Toselli, Massimo Messori, Giulia Scalet
Thermally-driven semi-crystalline polymer networks are capable to achieve both the one-way shape-memory effect and two-way shape-memory effect under stress and stress-free conditions, therefore representing an appealing class of polymers for applications requiring autonomous reversible actuation and shape changes. In these materials, the shape-memory effects are achieved by leveraging the synergistic interaction between one or more crystalline phases and the surrounding amorphous ones that are present within the network itself. The present paper introduces a general framework for the finite strain continuum phenomenological modeling of the thermo-mechanical and shape-memory behavior of multi-phase semi-crystalline polymer networks. Model formulation, including the definition of phase and control variables, kinematic assumptions, and constitutive specifications, is introduced and thoroughly discussed. Theoretical derivations are general and easily adaptable to all cross-linked systems which include two or more crystalline domains or a single crystalline phase with a wide melting range and manifest macroscopically the one-way shape-memory effect and the two-way shape-memory effect under stress and stress-free conditions. Model capabilities are validated against experimental data for copolymer networks with two different crystalline phases characterized by well-separated melting and crystallization transitions. Results demonstrate the accuracy of the proposed model in predicting all the phenomena involved and in furnishing a useful support for future material and application design purposes.
Soft Condensed Matter (cond-mat.soft)
This work was funded by the European Union ERC CoDe4Bio Grant ID 101039467 under the funding programme Horizon Europe
Journal of the Mechanics and Physics of Solids, Volume 195, February 2025, 105955
Magnetization reversal of finite-length Co and Fe atomic chains on Pt(332) surface: numerical calculations and a new theoretical approach
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
S.V. Kolesnikov, E.S. Glazova, A.M. Saletsky
Different mechanisms of magnetization reversal in finite-length Co and Fe chains on the Pt(332) surface have been investigated, taking into account the Dzyaloshinskii-Moriya interaction. It has been found that the magnetization reversal in short atomic chains occurs through the simultaneous reversal of all magnetic moments. In contrast, the magnetization reversal in long atomic chains is facilitated by the formation of domain walls, which exhibit distinct structures for Co and Fe atomic chains. Using the geodesic nudged elastic band method, we have determined the energy barriers for magnetization reversal in chains consisting of 5 to 100 atoms. Additionally, the frequency prefactors have been calculated within the framework of the harmonic approximation of transition state theory. Notably, the dependencies of these prefactors on chain length and external magnetic field are significant and non-monotonic. We propose a theoretical approach that qualitatively describes the numerical dependencies for both the energy barriers and the frequency prefactors. The magnetization curves derived from our theoretical estimates show qualitative agreement with the results of numerical calculations. This analytical approach enables the estimation of the coercive force of atomic chains across a wide range of lengths, temperatures, sweeping rates, and model parameters. The proposed theoretical framework is applicable not only to the Co and Fe chains on the Pt(332) surface but also to a broad class of one-dimensional magnetic systems.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech), Computational Physics (physics.comp-ph)
19 pages, 7 figures, 1 table, 89 references
Charge transport limited by nonlocal electron-phonon interaction. I. Hierarchical equations of motion approach
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Studying charge transport in models with nonlocal carrier-phonon interaction is difficult because it requires finite-temperature real-time correlation functions of mixed carrier-phonon operators. Focusing on models with discrete undamped phonon modes, we show that such correlation functions can be retrieved from the hierarchical equations of motion (HEOM), although phonons have been integrated out. Our procedure relies on the explicit expression of HEOM auxiliaries in terms of phonon creation and annihilation operators. It reveals that the auxiliaries describe multiphonon-assisted carrier transitions induced by genuine many-phonon correlations, from which lower-order correlations are subtracted according to the finite-temperature Wick's theorem. Applying the procedure to our recently developed momentum-space HEOM method featuring a specific hierarchy closing, we compute the numerically exact dynamical mobility of a carrier within the one-dimensional Peierls model. The carrier mobility at moderate temperatures decreases with increasing interaction, whereas high temperatures see the opposite trend, reflecting the prevalence of the phonon-assisted current over the purely electronic band current. The pronounced finite-size effects and HEOM instabilities delimit the range of applicability of our approach to moderate interactions, moderate to high temperatures, and not too fast phonons. Importantly, this range comprises the values relevant for charge transport in crystalline organic semiconductors, and we present and discuss the corresponding numerically exact results in a companion paper.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph), Quantum Physics (quant-ph)
Main text: 25 pages, 7 figures; Supplemental material: 6 pages, 1 figure; This submission is accompanied by Part II. Numerically exact quantum dynamics in the slow-phonon regime
Charge transport limited by nonlocal electron-phonon interaction. II. Numerically exact quantum dynamics in the slow-phonon regime
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Transport of charge carriers in mechanically soft semiconductors is mainly limited by their interaction with slow intermolecular phonons. Carrier motion exhibits a crossover from superdiffusive to subdiffusive, producing a distinct low-frequency peak in the dynamical-mobility profile. These features can be understood within approaches relying on the timescale separation between carrier and phonon dynamics, such as the transient localization scenario (TLS). However, recovering them from fully quantum dynamics has proved elusive. Using the hierarchical equations of motion (HEOM)-based approach exposed in a companion paper, we study carrier transport in the one-dimensional Peierls model near the adiabatic limit. We find that the TLS approximates HEOM dynamics very well at higher temperatures and for stronger interactions. Then, the transport is predominantly phonon-assisted, and turns diffusive from the subdiffusive side well before one phonon period. In contrast, the band current dominates at moderate temperatures and interactions, relevant for transport in realistic materials. We then conclude that the super-to-subdiffusive crossover is transient, so that the diffusive motion sets in from the superdiffusive side after a couple of phonon periods. The low-frequency dynamical mobility then additionally exhibits a dip at approximately one phonon frequency, and the zero-frequency peak. Our findings in this moderate regime show limitations of the TLS, and support the results of the most advanced quantum-classical simulations. We expect that the qualitative differences between HEOM and TLS dynamics would diminish for a more realistic phonon density of states.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Chemical Physics (physics.chem-ph), Quantum Physics (quant-ph)
Main text: 13 pages, 4 figures; Supplemental material: 7 pages, 4 figures; This submission is accompanied by Part I. Hierarchical equations of motion approach
Electron-phonon coupling in lattice engineering of lithium niobate single crystal thin films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Guoqiang Shi, Kunfeng Chen, Hui Hu, Gongbin Tang, Dongfeng Xue
Lithium niobate (LN) single crystal thin films are a high-performance photonic platform with applications in electro-optic modulators, nonlinear optical devices, optical frequency combs, and acousto-optic modulators. LN's significance in photonics parallels silicon's in electronics, addressing challenges like high power consumption and slow communication speeds, and offering potential for broad applications in optical communications, quantum computing, and artificial intelligence. Despite progress in developing LN-based photonic structures, achieving low-loss, reconfigurable, and large-scale devices requires improved processing techniques. This work introduces a quantum design methodology based on LN's crystal structure, utilizing electron-phonon coupling through external field perturbations. Multiscale structural analysis is performed with techniques such as time-of-flight secondary ion mass spectrometry, aberration-corrected transmission electron microscopy, and X-ray absorption spectra to identify and control defect structures. Angle-resolved Raman spectroscopy, femtosecond transient absorption spectroscopy, and Density Functional Theory further reveal the mechanisms of electron-phonon coupling. These findings establish a framework for designing LN-based quantum devices with enhanced performance and diverse functionalities.
Materials Science (cond-mat.mtrl-sci)
Control of magnon frequency combs in magnetic rings
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Christopher Heins, Attila Kákay, Joo-Von Kim, Gregor Hlawacek, Jürgen Fassbender, Katrin Schultheiss, Helmut Schultheiss
Using Brillouin light scattering microscopy, we study the rich dynamics in magnetic disks and rings governed by non-linear interactions, focusing on the role of vortex core dynamics on the spin-wave eigenmode spectrum. By strongly exciting quantized magnon modes in magnetic vortices, self-induced magnon Floquet states are populated by the intrinsic nonlinear coupling of magnon modes to the vortex core gyration. In magnetic rings, however, this generation is suppressed even when exciting the system over a large power range. To retrieve the rich nonlinear dynamics in rings, we apply external in-plane magnetic fields by which the vortex core is restored. Our findings demonstrate how to take active control of the nonlinear processes in magnetic structures of different topology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Effect of particle and substrate wettability on evaporation-driven assembly of colloidal monolayers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Qingguang Xie, Tian Du, Christoph J. Brabec, Jens Harting
Assembled monolayers of colloidal particles are crucial for various applications, including opto-electronics, surface engineering, as well as light harvesting, and catalysis. A common approach for self-assembly is the drying of a colloidal suspension film on a solid substrate using technologies such as printing and coating. However, this approach often presents challenges such as low surface coverage, stacking faults, and the formation of multiple layers. We numerically investigate the influence of substrate and particle wettability on the deposited pattern. Higher substrate wettability results in a monolayer with a hexagonal arrangement of deposited particles on the substrate. Conversely, lower substrate wettability leads to droplet formation after the film ruptures, leading to the formation of particle clusters. Furthermore, we reveal that higher particle wettability can mitigate the impact of the substrate wettability and facilitate the formation of highly ordered monolayers. We propose theoretical models predicting the surface coverage fraction dependent on particle volume fraction, initial film thickness, particle radius, as well as substrate and particle wettability, and validate these models with simulations. Our findings provide valuable insights for optimizing the deposition process in the creation of assembled monolayers of colloidal particles.
Soft Condensed Matter (cond-mat.soft), Chemical Physics (physics.chem-ph)
9 pages, 6 figures
Migration of phthalate plasticisers in heritage objects made of poly(vinyl chloride): mechanical and environmental aspects
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Sonia Bujok, Tomasz Pańczyk, Kosma Szutkowski, Dominika Anioł, Sergii Antropov, Krzysztof Kruczała, Łukasz Bratasz
To clean or not to clean? The solution to this dilemma is related to understanding the plasticiser migration which has a few practical implications for the state of museum artefacts made of plasticised poly(vinyl chloride) - PVC and objects stored in their vicinity. The consequences of this process encompass aesthetic changes due to the presence of exudates and dust deposition, an increase in air pollution and the development of mechanical stresses. Therefore, this paper discusses the plasticiser migration in PVC to provide evidence and support the development of recommendations and guidelines for conservators, collection managers and heritage scientists. Particularly, the investigation is focused on the migration of the ortho-phthalates representing the group of the most abundant plasticisers in PVC collections. The predominance of inner diffusion or surface emission (evaporation) determining the rate-limiting step of the overall migration process is considered a fundament for understanding the potential environmental and mechanical risk. According to this concept, general correlations for various ortho-phthalates are proposed depending on their molar mass with the support of molecular dynamics simulations and NMR diffusometry. The study reveals that for the majority of the PVC objects in collections, the risk of accelerated migration upon mild removal of surface plasticiser exudate is low. Thus, surface cleaning would allow for diminishing dust deposition and air pollution by phthalate-emitting objects in a museum environment. Bearing in mind simplicity and the need for fast decision-supporting solutions, the step-by-step protocol for non-destructive identification and quantification of plasticisers in objects made of or containing plasticised PVC, determination of the physical state of investigated artefacts and rate-limiting process of plasticiser migration is proposed.
Materials Science (cond-mat.mtrl-sci)
Preprint. Submitted to Journal of Environmental Management on 10th September 2024. The studies were financially supported by the PVCare project Preventive Conservation Strategies for Poly(vinyl chloride) Objects funded through the OPUS-LAP 20 programme by NCN (National Science Center, Poland, project no. 2020/39/I/HS2/00911) and ARIS (Slovenian Research and Innovation Agency, project no. N1-0241)
Unidirectional motion of topological defects mediating continuous rotation processes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Marisel Di Pietro Martínez, Luke Alexander Turnbull, Jeffrey Neethirajan, Max Birch, Simone Finizio, Jörg Raabe, Edouard Lesne, Anastasios Markou, María Vélez, Aurelio Hierro-Rodríguez, Marco Salvalaglio, Claire Donnelly
Topological defects play a critical role across many fields, mediating phase transitions and macroscopic behaviors as they move through space. Their role as robust information carriers has also generated much attention. However, controlling their motion remains challenging, especially towards achieving motion along well-defined paths which typically require predefined structural patterning. Here we demonstrate the tunable, unidirectional motion of topological defects, specifically magnetic dislocations in a weak magnetic stripe pattern, induced by external magnetic field in a laterally unconfined thin film. This motion is shown to mediate the overall continuous rotation of the stripe pattern. We determine the connection between the unidirectional motion of dislocations and the underlying three-dimensional (3D) magnetic structure by performing 3D magnetic vectorial imaging with in situ magnetic fields. A minimal model for dislocations in stripe patterns that encodes the symmetry breaking induced by the external magnetic field reproduces the motion of dislocations that facilitate the 2D rotation of the stripes, highlighting the universality of the phenomenon. This work establishes a framework for studying the field-driven behavior of topological textures and designing materials that enable well defined, controlled motion of defects in unconfined systems, paving the way to manipulate information carriers in higher-dimensional systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
18 pages, 5 figures
Thermodynamics of a compressible lattice gas crystal: Generalized Gibbs-Duhem equation and adsorption
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Compressible lattice gas models are used in material science to understand the coupling between composition and strain in alloys. The seminal work in this field is the 1973 Larché-Cahn paper (Acta Metall. {} 1051-1063). Single-phase crystals in Larché-Cahn theory are stable under open constant pressure, constant temperature conditions. The Gibbs free energy does not have to match the product \(\mu N\) of the number of particles \(N\) and their chemical potential \(\mu\). Discrepancies already arise under hydrostatic stress. The reason is that volume strain is defined with respect to a fixed reference state. The elastic energy is not proportional to volume and the Gibbs-Duhem relation valid for liquids is violated. Extensivity can be recovered by treating the number of lattice sites \(M\) as an additional thermodynamic variable. This assigns a formal chemical potential \(\nu\) to the immobile lattice sites. The difference $ G-N $ can be identified with \(\nu M\). We have worked this out for a one-component compressible lattice gas crystal. Shear stress is omitted. The reinstated Gibbs-Duhem equation can be cast in the form of an adsorption equation and applied to quantify the tendency to vacancy creation. The derivative of population with respect to chemical potential at constant pressure and temperature is compared to the corresponding susceptibility in a fixed volume open system. We find that the difference is proportional to the elastic constant of the bare lattice, confirming that this quantity is the crucial macroscopic property distinguishing a solid under hydrostatic stress from a liquid.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
19 pages
Photon-assisted stochastic resonance in nanojunctions
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Michael Ridley, Leo Bellassai, Michael Moskalets, Lev Kantorovich, Riku Tuovinen
We study stochastic resonance in molecular junctions driven by a periodically-varying external field. This is done using the time-dependent Landauer-B{ü}ttiker formalism, which follows from exact analytical solutions to the Kadanoff-Baym equations describing the molecular junction subject to an arbitrary time-dependent bias. We focus on a double quantum dot nanojunction and compare the effects of the temperature with the fluctuating bias in the statically-driven case. We then consider the combined effect of AC-driving and white noise fluctuations on the rectified current through the nanojunction, and find a stochastic resonance effect, where at certain driving conditions the bias fluctuations enhance the current signal. The study is then extended to include the color noise in the applied bias, so that the combined effect of the color noise correlation time and driving frequency on stochastic resonance is investigated. We thereby demonstrate that photon-assisted transport can be optimized by a suitably tuned environment.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Statistical Mechanics (cond-mat.stat-mech)
Polymorphism and Magnetism in a Kitaev Honeycomb Cobaltate KCoAsO\(_4\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Yuya Haraguchi, Daisuke-Nishio Hamane, Hiroko Aruga Katori
We report the synthesis, crystal structure, and magnetic properties of a new Kitaev honeycomb cobaltate, KCoAsO\(_4\), which crystallizes in two distinct forms: \(P2/c\) and \(R\bar{3}\) space groups. Magnetic measurements reveal ordering temperatures of $$14 K for the \(P2/c\) structure and $$10.5 K for the \(R\bar{3}\) structure. The \(P2/c\)-type KCoAsO\(_4\) sample exhibits a complex temperature-field phase diagram, including a field-induced phase, while the \(R\bar{3}\)-type KCoAsO\(_4\) shows a simpler phase diagram with a single magnetically ordered phase. The observed differences in magnetic properties are attributed to subtle structural variations, strongly suggesting that local structural changes play a crucial role in determining the magnetism of cobaltate-based Kitaev materials.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
16 pages, 5 figures
Anisotropic active Brownian particle in two dimensions under stochastic resetting
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-10 20:00 EST
We analytically investigate the dynamic behavior of an an-isotropic active Brownian particle under various stochastic resetting protocols in two dimensions. The motion of shape-asymmetric active Brownian particles in two dimensions leads to an-isotropic diffusion at short times, whereas rotational diffusion causes the transport to become isotropic at longer times. We have considered three different resetting protocols: (a) complete resetting, when both position and orientation are reset to their initial states, (b) only position is reset to its initial state, (c) only orientation is reset to its initial state. We reveal that orientation resetting sustains asymmetry even at late times. When both the spatial position and orientation are subject to resetting, a complex position probability distribution forms in the steady state. All the analytical findings are thoroughly validated by corresponding simulation results.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
21 pages, 13 figures
Magnetism and electronic dynamics in \(CuCr_{2-x}Sn_xS_4\) spinels studied by transferred hyperfine fields at \(^{119}Sn\) and muon spin rotation and relaxation
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Elaheh Sadrollahi, Cynthia P. C. Medrano, Magno A.V. Heringer, E. M. Baggio Saitovitch, Lilian Prodan, Vladimir Tsurkan, F. Jochen Litterst
We investigated magnetization, muon spin rotation (\(\mu\)SR), and \(^{119}Sn\) Mössbauer spectroscopy on Sn substituted \(CuCr_{2-x}Sn_xS_4\) (x=0.03 and 0.08) spinel compounds. The magnetization and \(\mu\)SR results reveal similar additional low-temperature magnetic transitions around 80 K and 40 K as found for the undoped material, indicating a magnetic ground state deviating from a simple collinear ferromagnet. The observed changes in the Mössbauer hyperfine spectra are less pronounced and are discussed in view of the different positions of the local probes \(\mu^+\) and \(^{119}Sn\) and their different magnetic coupling to the magnetic Cr lattice. Above 80 K, both \(\mu\)SR and Mössbauer spectra show temperature-dependent inhomogeneous broadening either due to structural or charge disorder and changing spin dynamics that can be related to a precursor magnetic phase above the well-defined static low-temperature phase.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 13 figures
Tree Models Machine Learning to Identify Liquid Metal based Alloy Superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-10 20:00 EST
Superconductors, which are crucial for modern advanced technologies due to their zero-resistance properties, are limited by low Tc and the difficulty of accurate prediction. This article made the initial endeavor to apply machine learning to predict the critical temperature (Tc) of liquid metal (LM) alloy superconductors. Leveraging the SuperCon dataset, which includes extensive superconductor property data, we developed a machine learning model to predict Tc. After addressing data issues through preprocessing, we compared multiple models and found that the Extra Trees model outperformed others with an R2 of 0.9519 and an RMSE of 6.2624 K. This model is subsequently used to predict Tc for LM alloys, revealing In0.5Sn0.5 as having the highest Tc at 7.01 K. Furthermore, we extended the prediction to 2,145 alloys binary and 45,670 ternary alloys across 66 metal elements and promising results were achieved. This work demonstrates the advantages of tree-based models in predicting Tc and would help accelerate the discovery of high-performance LM alloy superconductors in the coming time.
Superconductivity (cond-mat.supr-con)
18 pages, 5 figures, 5 tables
Multi-Particle Collision Framework for Active Polar Fluids
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Oleksandr Baziei, Benjamín Loewe, Tyler N. Shendruk
Sufficiently dense intrinsically out-of-equilibrium suspensions, such as those observed in biological systems, can be modelled as active fluids characterised by their orientational symmetry. While mesoscale numerical approaches to active nematic fluids have been developed, polar fluids are simulated as either ensembles of microscopic self-propelled particles or continuous hydrodynamic-scale equations of motion. To better simulate active polar fluids in complex geometries or as a solvent for suspensions, mesoscale numerical approaches are needed. In this work, the coarse-graining Multi-Particle Collision Dynamics (MPCD) framework is applied to three active particle models to produce mesoscale simulations of polar active fluids. The first active-polar MPCD (AP-MPCD) is a variant of the Vicsek model, while the second and third variants allow the speed of the particles to relax towards a self-propulsion speed subject to Andersen and Langevin thermostats, respectively. Each of these AP-MPCD variants exhibit a flocking transition at a critical activity and banding in the vicinity of the transition point. We leverage the mesoscale nature of AP-MPCD to explore flocking in the presence of external fields, which destroys banding, and anisotropic obstacles, which act as a ratchet that biases the flocking direction. These results demonstrate the capacity of AP-MPCD to capture the known phenomenology of polar active suspensions, and its versatility to study active polar fluids in complex scenarios.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
16 pages, 18 figures
Rashba effect modulation in two-dimensional A2B2Te6 (A = Sb, Bi; B = Si, Ge) materials via charge transfer
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Haipeng Wu, Qikun Tian, Jinghui Wei, Ziyu Xing, Guangzhao Qin, Zhenzhen Qin
Designing two-dimensional (2D) Rashba semiconductors, exploring the underlying mechanism of Rashba effect, and further proposing efficient and controllable approaches are crucial for the development of spintronics. On the basis of first-principles calculations, we here theoretically design all possible types (common, inverse, and composite) of Janus structures and successfully achieve numerous ideal 2D Rashba semiconductors from a series of five atomic-layer A2B2Te6 (A = Sb, Bi; B = Si, Ge) materials. Considering the different Rashba constant {}R and its modulation trend under external electric field, we comprehensively analyze the intrinsic electric field Ein in terms of work function, electrostatic potential, dipole moment, and inner charge transfer. Inspired by the quantitative relationship between charge transfer and the strength of Ein and even the {}R, we propose a straightforward strategy of introducing a single adatom onto the surface of 2D monolayer to introduce and modulate the Rashba effect. Lastly, we also examine the growth feasibility and electronic structures of the Janus Sb2Ge2Se3Te3 system and Janus-adsorbed systems on a 2D BN substrate. Our work not only conducts a detailed analysis of A2B2Te6-based Rashba systems, but also proposes a new strategy for efficiently and controllably modulating the {}R through the reconfiguration of charge transfer.
Materials Science (cond-mat.mtrl-sci)
Three-body scattering hypervolume of two-component fermions in three dimensions
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-01-10 20:00 EST
Jiansen Zhang, Zipeng Wang, Shina Tan
We study the zero-energy collision of three fermions, two of which are in the spin-down (\(\downarrow\)) state and one of which is in the spin-up (\(\uparrow\)) state. Assuming that the two-body and the three-body interactions have a finite range, we find a parameter, \(D\), called the three-body scattering hypervolume. We study the three-body wave function asymptotically when three fermions are far apart or one spin-\(\uparrow\) (spin-\(\downarrow\)) fermion and one pair, formed by the other two fermions, are far apart, and derive three asymptotic expansions of the wave function. The three-body scattering hypervolume appears in the coefficients of such expansions at the order of \(B^{-5}\), where \(B\) is the hyperradius of the triangle formed by the three fermions. When the interactions are weak, we calculate \(D\) approximately using the Born expansion. We also analyze the energy shift of three such fermions in a large periodic cube due to \(D\) and generalize this result to the many-fermion system. \(D\) also determines the three-body recombination rate in two-component Fermi gases, and we calculate the three-body recombination rate in terms of \(D\) and the density and temperature of the gas.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph), Quantum Physics (quant-ph)
20 pages, 2 figures
Two- and many-body physics of ultracold molecules dressed by dual microwave fields
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-01-10 20:00 EST
Fulin Deng, Xinyuan Hu, Wei-Jian Jin, Su Yi, Tao Shi
We investigate the two- and many-body physics of the ultracold polar molecules dressed by dual microwaves with distinct polarizations. Using Floquet theory and multichannel scattering calculations, we identify a regime with the largest elastic-to-inelastic scattering ratio which is favorable for performing evaporative cooling. Furthermore, we derive and, subsequently, validate an effective interaction potential that accurately captures the dynamics of microwave-shielded polar molecules (MSPMs). We also explore the ground-state properties of the ultracold gases of MSPMs by computing physical quantities such as gas density, condensate fraction, momentum distribution, and second-order correlation. It is shown that the system supports a weakly correlated expanding gas state and a strongly correlated self-bound gas state. Since the dual-microwave scheme introduces addition control knob and is essential for creating ultracold Bose gases of polar molecules, our work pave the way for studying two- and many-body physics of the ultracold polar molecules dressed by dual microwaves.
Quantum Gases (cond-mat.quant-gas)
Application of pretrained universal machine-learning interatomic potential for physicochemical simulation of liquid electrolytes in Li-ion battery
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Suyeon Ju, Jinmu You, Gijin Kim, Yutack Park, Hyungmin An, Seungwu Han
Achieving higher operational voltages, faster charging, and broader temperature ranges for Li-ion batteries necessitates advancements in electrolyte engineering. However, the complexity of optimizing combinations of solvents, salts, and additives has limited the effectiveness of both experimental and computational screening methods for liquid electrolytes. Recently, pretrained universal machine-learning interatomic potentials (MLIPs) have emerged as promising tools for computational exploration of complex chemical spaces with high accuracy and efficiency. In this study, we evaluated the performance of the state-of-the-art equivariant pretrained MLIP, SevenNet-0, in predicting key properties of liquid electrolytes, including solvation behavior, density, and ion transport. To assess its suitability for extensive material screening, we considered a dataset comprising 20 solvents. Although SevenNet-0 was predominantly trained on inorganic compounds, its predictions for the properties of liquid electrolytes showed good agreement with experimental and \(\textit{ab initio}\) data. However, systematic errors were identified, particularly in the predicted density of liquid electrolytes. To address this limitation, we fine-tuned SevenNet-0, achieving improved accuracy at a significantly reduced computational cost compared to developing bespoke models. Analysis of the training set suggested that the model achieved its accuracy by generalizing across the chemical space rather than memorizing specific configurations. This work highlights the potential of SevenNet-0 as a powerful tool for future engineering of liquid electrolyte systems.
Materials Science (cond-mat.mtrl-sci)
14 pages, 6 figures, Supplementary information included as ancillary file (+33 pages)
Control Strategies for Maintaining Transport Symmetries Far From Equilibrium
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-01-10 20:00 EST
We present two schemes for controlling the transport dynamics of mesoscopic devices. In both approaches, we manipulate the system's output - such as particle currents and energy flows - while maintaining symmetric transport properties, even under far-from-equilibrium conditions. We provide exact descriptions of the modified processes under each scheme and investigate their characteristics. Notably, one of the schemes is shown to minimize the dissimilarity between the original and modified processes, as quantified by the Kullback-Leibler divergence. These findings have the potential to enhance the design and control of mesoscopic systems.
Statistical Mechanics (cond-mat.stat-mech)
A Thermodynamic Theory of Proximity Ferroelectricity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Eugene A. Eliseev, Anna N. Morozovska, Jon-Paul Maria, Long-Qing Chen, Venkatraman Gopalan
Proximity ferroelectricity has recently been reported as a new design paradigm for inducing ferroelectricity, where a non-ferroelectric polar material becomes a ferroelectric by interfacing with a thin ferroelectric layer. Strongly polar materials, such as AlN and ZnO, which were previously unswitchable with an external field below their dielectric breakdown fields, can now be switched with practical coercive fields when they are in intimate proximity to a switchable ferroelectric. Here, we develop a general Landau-Ginzburg theory of proximity ferroelectricity in multilayers of non-ferroelectrics and ferroelectrics to analyze their switchability and coercive fields. The theory predicts regimes of both "proximity switching" where the multilayers collectively switch, as well as "proximity suppression" where they collectively do not switch. The mechanism of the proximity ferroelectricity is an internal electric field determined by the polarization of the layers and their relative thickness in a self-consistent manner that renormalizes the double-well ferroelectric potential to lower the steepness of the switching barrier. Further reduction in the coercive field emerges from charged defects in the bulk that act as nucleation centers. The application of the theory to proximity ferroelectricity in Alx-1ScxN/AlN and Zn1-xMgxO/ZnO bilayers is demonstrated. The theory further predicts that multilayers of dielectric/ferroelectric and paraelectric/ferroelectric layers can potentially result in induced ferroelectricity in the dielectric or paraelectric layers, resulting in the entire stack being switched, an exciting avenue for new discoveries. This thawing of "frozen ferroelectrics", paraelectrics and potentially dielectrics, promises a large class of new ferroelectrics with exciting prospects for previously unrealizable domain-patterned optoelectronic and memory technologies.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
42 pages including 7 figures and 4 Appendices. To be submitted to Physical Review
Correlation between Complex Spin Textures and the Magnetocaloric and Hall Effects in Eu(Ga\(_{1-x}\)Al\(_x\))\(_4\) (\(x\) = 0.9, 1)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Kelly J. Neubauer, Kevin Allen, Jaime M. Moya, Mason L. Klemm, Feng Ye, Zachary Morgan, Lisa DeBeer-Schmitt, Wei Tian, Emilia Morosan, Pengcheng Dai
Determining the electronic phase diagram of a quantum material as a function of temperature (T) and applied magnetic field (H) forms the basis for understanding the microscopic origin of transport properties, such as the anomalous Hall effect (AHE) and topological Hall effect (THE). For many magnetic quantum materials, including EuAl\(_4\), a THE arises from a topologically protected magnetic skyrmion lattice with a non-zero scalar spin chirality. We identified a square skyrmion lattice (sSkL) peak in Eu(Ga\(_{1-x}\)Al\(_x\))\(_4\) (\(x\) = 0.9) identical to the peak previously observed in EuAl\(_4\) by performing neutron scattering measurements throughout the phase diagram. Comparing these neutron results with transport measurements, we found that in both compounds the maximal THE does not correspond to the sSkL area. Instead of the maximal THE, the maximal magnetocaloric effect (MCE) boundaries better identify the sSkL lattice phase observed by neutron scattering measurements. The maximal THE therefore arises from interactions of itinerant electrons with frustrated spin fluctuations in a topologically trivial magnetic state.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
Galvanic molecular intercalation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Daniel Tezze, Covadonga Álvarez, Daniel Margineda, José Manuel Pereira, Umer Ahsan, Vlastimil Mazanek, Yogesh Kumar Maurya, Aurelio Mateo-Alonso, Frederik M. Schiller, Fèlix Casanova, Samuel Mañas-Valero, Eugenio Coronado, Iván Rivilla, Zdenek Sofer, Beatriz Martín-García, Maider Ormaza, Luis E. Hueso, Marco Gobbi
The intercalation of molecular species between the layers of van der Waals (vdW) materials has recently emerged as a powerful approach to combine the remarkable electronic and magnetic properties of vdW materials with the chemical flexibility of organic molecules. However, the full transformative potential of molecular intercalation remains underexplored, largely due to the lack of simple, broadly applicable methods that preserve high crystalline quality down to the few-layer limit. Here, we introduce a simple galvanic approach to intercalate different molecules into various vdW materials under ambient conditions, leveraging the low reduction potential of selected metals to enable a spontaneous molecular insertion. We employ our method, which is particularly well-suited for the in-situ intercalation of few-layer-thick crystals, to intercalate nine vdW materials, including magnets and superconductors, with molecules ranging from conventional alkylammonium ions to metallorganic and bio-inspired chiral cations. Notably, intercalation leads to a molecule-dependent enhancement of the superconducting transition in 2H-TaS2, reaching a critical temperature of 4.7 K, higher than TaS2 monolayers. Additionally, RuCl3 exhibits an unprecedented transition from antiferromagnetic to ferrimagnetic ordering upon intercalation with cobaltocenium. These results establish our approach as a versatile technique for engineering atomically thin quantum materials and heterostructures, unlocking the transformative effects of molecular intercalation.
Materials Science (cond-mat.mtrl-sci)
Competition of superconducting pairing symmetries in La3Ni2O7
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-10 20:00 EST
Han-Xiang Xu, Yue Xie, Daniel Guterding, Zhijun Wang
The recent discovery of superconductivity in the bilayer Ruddlesden-Popper nickelate La3Ni2O7 under high pressure has generated much interest in the superconducting pairing mechanism of nickelates. Various theoretical approaches have been applied to the study of superconductivity in La3Ni2O7, but lead to a number of contradicting results. We argue that different superconducting states in La3Ni2O7 are in close competition and at the same time particularly sensitive to the choice of interaction parameters as well as changes of the electronic structure through pressure. Our study uses a multi-orbital Hubbard model, incorporating all Ni 3d and O 2p states. We analyze the superconducting pairing mechanism of La3Ni2O7 within the random phase approximation and find a transition between d-wave and sign-changing s-wave pairing states as a function of pressure and interaction parameters, which is driven by spin-fluctuations with different wave vectors. Our work paves the way to understanding seemingly contradictory theoretical results within a unified framework.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
MoSi2N4-like crystals -- the new family of two-dimensional materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Tatiana Latychevskaia, Denis A. Bandurin, Kostya S. Novoselov
Recently-synthesised MoSi2N4 is the first septuple layer two-dimensional material, which doesn't naturally occurs as a layered crystal, and has been obtained with CVD growth. It can be considered as MoN2 crystal (with a crystal structure of MoS2) intercalating Si2N2 two-dimensional layer (with the structure similar to InSe). Such classification gave rise to the understanding of the electronic properties of the material, but also to the prediction of other members of the family (many dozens of them) as well as to the way to classify those. Whereas the originally-synthesised MoSi2N4 is a semiconductor, some of the members of the family are also metallic and some even demonstrate magnetic properties. Interestingly, the room-temperature mobility predicted for such crystals can be as high few thousands cm^2/V(hole mobility typically higher than electron) with some record cases as high as 5^4 cm^22/V, making these materials strong contenders for future electronic applications. The major interest towards these materials is coming from the septuple layer structure, which allows multiple crystal phases, but also complex compositions, in particular those with broken mirror-reflection symmetry against the layer of metal atoms.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Nature Reviews Physics volume 6, pages 426-438 (2024)
Elliptical stability of hopfions in bulk helimagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Magnetic hopfions are three-dimensional topological solitons with non-zero Hopf index \({\cal H}\) in the vector field of material's local magnetization. In this Letter elliptical stability of hopfions with \({\cal H}=1\) in a classical helimagnet is studied on the basis of a variational model. It is shown that, depending on their internal structure (vortex and antivortex tubes ordering), the hopfions can either be stable in a bulk magnet or unstable with respect to elongation along their central axis. It is found that the energy of stable hopfions is always below the energy of the \(2\pi\)-skyrmion lattice in the same material, suggesting the possibility to use \(2\pi\)-skyrmions as a precursor for hopfion nucleation. Stability diagram for hopfions on the magnetic anisotropy-field phase diagram is computed numerically. Explicit analytical expressions for some of its critical lines are derived.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Pattern Formation and Solitons (nlin.PS)
6 pages, 3 figures
First-Principles and Machine Learning Insights into the Design of DOTT-Carbon and its Lithium-Ion Storage Capacity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Kleuton. A. L. Lima, Ana V. P. Abreu, Alysson M. A. Silva, Luiz A. Ribeiro Jr
Two-dimensional (2D) carbon-based materials are promising candidates for developing more efficient green energy conversion and storage technologies. This study presents a new 2D carbon allotrope, DOTT-Carbon, characterized by its distinctive and multi-ring structure featuring 12-, 8-, 4-, and 3-membered rings of carbon atoms. We explore its structural, mechanical, and lithium-ion storage properties by employing density functional theory and machine learning simulations. Phonon calculations confirm its structural stability and ab initio molecular dynamics simulations demonstrate its thermal resilience at elevated temperatures. The material exhibits anisotropic mechanical properties, with Young's modulus values varying between 280-330 GPa. DOTT-Carbon displays a lithium-ion storage capacity of 446.28 mAh/g, complemented by a low diffusion barrier (0.2-0.9 eV) and a high diffusion coefficient ($ > 1.0 ^{-6}$ cm\(^{2}\)/s), possibly facilitating efficient lithium-ion transport. The stable open circuit voltage of 0.28 V also indicates its suitability as an anode material.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
19 pages
Evidences for local non-centrosymmetricity and strong phonon anomaly in EuCu2As2: A Raman spectroscopy and lattice dynamics study
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Debasmita Swain, Mainak Dey Sarkar, Andrzej Ptok, G. Vaitheeswaran, Anushree Roy, Sitikantha D Das
Phonon modes and their association with the electronic states have been investigated for the metallic EuCu\(_{2}\)As\(_{2}\) system. In this work, we present the Raman spectra of this pnictide system which clearly shows the presence of seven well defined peaks above \(100\)~cm\(^{-1}\) that is consistent with the locally non-centrosymmetric {} crystal structure, contrary to that what is expected from the accepted symmorphic {} structure. Lattice dynamics calculations using the {} symmetry attest that there is a commendable agreement between the calculated phonon spectra at the \(\Gamma\) point and the observed Raman mode frequencies, with the most intense peak at \(\sim 232\)~cm\(^{-1}\) being ascribed to the A\(_{1g}\) mode. Temperature dependent Raman measurements show that there is a significant deviation from the expected anharmonic behaviour around \(165\)~K for the A\(_{1g}\) mode, with anomalies being observed for several other modes as well, although to a lesser extent. Attempts are made to rationalize the observed anomalous behavior related to the hardening of the phonon modes, with parallels being drawn from metal dichalcogenide and allied systems. Similarities in the evolution of the Raman peak frequencies with temperature seem to suggest a strong signature of a subtle electronic density wave instability below \(165\)~K in this compound.
Strongly Correlated Electrons (cond-mat.str-el)
J Phys Condens Matter . 2024 May 23;36(33)
Dipolar magnetostirring protocol for three-well atomtronic circuits
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-01-10 20:00 EST
Héctor Briongos-Merino, Felipe Isaule, Montserrat Guilleumas, Bruno Juliá-Díaz
We propose a magnetostirring protocol to create persistent currents on an annular system. Under this protocol, polar bosons confined in a three-well ring circuit reach a state with high average circulation. We model the system with an extended Bose-Hubbard Hamiltonian and show that the protocol can create circulation in an atomtronic circuit for a range of tunable parameters. The performance and robustness of this scheme are examined, in particular considering different interaction regimes. We also present a method for predicting the optimal protocol parameters, which improves protocol's scalability and enables its application to systems with large numbers of bosons. This overcomes computational limitations and paves the way for exploring macroscopic quantum phenomena.
Quantum Gases (cond-mat.quant-gas)
Unveiling structure-property correlations in ferroelectric \(Hf_{0.5}Zr_{0.5}O_2\) films using variational autoencoders
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Kévin Alhada-Lahbabi, Brice Gautier, Damien Deleruyelle, Grégoire Magagnin
While \(Hf_{0.5}Zr_{0.5}O_2\) (HZO) thin films hold significant promise for modern nanoelectronic devices, a comprehensive understanding of the interplay between their polycrystalline structure and electrical properties remains elusive. Here, we present a novel framework combining phase-field (PF) modeling with Variational Autoencoders (VAEs) to uncover structure-property correlations in polycrystalline HZO. Leveraging PF simulations, we constructed a high-fidelity dataset of \(P-V\) loops by systematically varying critical material parameters, including grain size, polar grain fraction, and crystalline orientation. The VAEs effectively encoded hysteresis loops into a low-dimensional latent space, capturing electrical properties while disentangling complex material parameters interdependencies. We further demonstrate a VAE-based inverse design approach to optimize \(P-V\) loop features, enabling the tailored design of device-specific key performance indicators (KPIs), including coercive field, remanent polarization, and loop area. The proposed approach offers a pathway to systematically explore and optimize the material design space for ferroelectric nanoelectronics.
Materials Science (cond-mat.mtrl-sci)
Double Majorana Vortex Flat Bands in the Topological Dirac Superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-10 20:00 EST
Zhongyi Zhang, Zixi Fang, Shengshan Qin, Peng Zhang, Hoi Chun Po, Xianxin Wu
Vortex lines, known as topological defects, are cable of trapping Majorana modes in superconducting topological materials. Previous studies have primarily focused on topological bands with conventional s-wave pairing. However, topological Dirac semimetals exhibiting a unique orbital texture can favor unconventional pairing when electronic correlations are significant. The topology of vortices in these systems has yet to be explored. In this work, we investigate the vortex bound states in superconducting Dirac semimetals, with a particular focus on the orbital-singlet unconventional pairing, which generates higher-order Majorana hinge modes. Remarkably, we identify robust double Majorana vortex flat bands at zero energy. In type-I Dirac semimetals, these Majorana flat bands are located between the projections of two superconduting Dirac points. In contrast, in type-II Dirac semimetals, they extend across the entire 1D Brillouin zone. These double flat bands arise from a nontrivial \(\mathbb{Z}_2\) topology defined by an effective particle-hole symmetry and are protected by the four-fold rotational symmetry. Additionally, we observe that moving the vortex line close to a hinge can trivialize the higher-order Majorana arc on the hinge, leaving a single Majorana mode at the vortex core due to the hybridization of Majorana modes. Finally, we discuss the potential experimental implications for correlated Dirac semimetals, such as electron-doped iron-based superconductors.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 6 figures
Quantifying superlubricity of bilayer graphene from the mobility of interface dislocations
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
Md Tusher Ahmed, Moon-ki Choi, Harley T Johnson, Nikhil Chandra Admal
Van der Waals (vdW) heterostructures subjected to interlayer twists or heterostrains demonstrate structural superlubricity, leading to their potential use as superlubricants in micro- and nano-electro-mechanical devices. However, quantifying superlubricity across the vast four-dimensional heterodeformation space using experiments or atomic-scale simulations is a challenging task. In this work, we develop an atomically informed dynamic Frenkel--Kontorova (DFK) model for predicting the interface friction drag coefficient of an arbitrarily heterodeformed bilayer graphene (BG) system. The model is motivated by MD simulations of friction in heterodeformed BG. In particular, we note that interface dislocations formed during structural relaxation translate in unison when a heterodeformed BG is subjected to shear traction, leading us to the hypothesis that the kinetic properties of interface dislocations determine the friction drag coefficient of the interface. The constitutive law of the DFK model comprises the generalized stacking fault energy of the AB stacking, a scalar displacement drag coefficient, and the elastic properties of graphene, which are all obtained from atomistic simulations. Simulations of the DFK model confirm our hypothesis since a single choice of the displacement drag coefficient, fit to the kinetic property of an individual dislocation in an atomistic simulation, predicts interface friction in any heterodeformed BG. By bridging the gap between dislocation kinetics at the microscale to interface friction at the macroscale, the DFK model enables a high-throughput investigation of strain-engineered vdW heterostructures.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Force-Velocity Relationship in Branched Actin Networks: Consequences of Entanglement, Drag and Stall Force
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Magid Badaoui, Serge Dmitrieff
We investigate the growth of a branched actin network under load. Using a combination of simulations and theory, we show that the network adapts to the load and exhibits two regimes: a finite velocity at low stress, followed by a power-law decay of the velocity as a function of stress. This decay is explained by a theoretical model relating branched network elasticity to filament entanglement. The finite maximum velocity is attributed to network drag, which dictates dynamics at low stress. Additionally, analysis of filament stall force contribution reveals a transition from a stalled network to a growing network, when the filament stall force exceeds a critical value controlled by the applied stress.
Soft Condensed Matter (cond-mat.soft)
Discovery of Spin-Crossover Candidates with Equivariant Graph Neural Networks
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-01-10 20:00 EST
Angel Albavera-Mata, Pawan Prakash, Jason B. Gibson, Eric Fonseca, Sijin Ren, Xiao-Guang Zhang, Hai-Ping Cheng, Michael Shatruk, S.B. Trickey, Richard G. Hennig
Swift discovery of spin-crossover materials for their potential application in quantum information devices requires techniques which enable efficient identification of suitably bistable candidates. To this end, we screened the Cambridge Structural Database to develop a specialized database of 1,439 materials and computed spin-switching energies from density functional theory for each material. The database was used to train an equivariant graph convolutional neural network to predict the magnitude of the spin-conversion energy. A test mean absolute error was 360 meV. For candidate identification, we equipped the system with a relevance-based classifier. This approach leads to a nearly four-fold improvement in identifying potential spin-crossover systems of interest as compared to conventional high-throughput screening.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Materials Science (cond-mat.mtrl-sci)
Real-frequency TPSC+DMFT investigation of the square-lattice Hubbard model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Lei Geng, Jiawei Yan, Philipp Werner
We investigate the two-dimensional Hubbard model using a real-frequency implementation of the TPSC+DMFT approach. This hybrid method combines the nonlocal correlations captured by the Two-Particle Self-Consistent (TPSC) approach with the local dynamical correlations of Dynamical Mean-Field Theory (DMFT). The results demonstrate that TPSC+DMFT effectively describes pseudogap physics and nonlocal fluctuations in the moderately correlated regime, while also reproducing the Mott insulating state at larger interaction strengths. For doped Mott insulators, we find that TPSC+DMFT captures the evolution of Fermi pockets into Fermi arcs, consistent with the results from cluster DMFT and photoemission studies. These findings highlight the capability of TPSC+DMFT to bridge the gap between weak and strong coupling physics in Hubbard models, providing insights into spin and charge fluctuations, as well as their role in the pseudogap formation.
Strongly Correlated Electrons (cond-mat.str-el)
Novel Electrical Characterization Method for Antiferroelectrics using a Positive Up Negative Down Approach
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Grégoire Magagnin, Martine Le Berre, Sara Gonzalez, Damien Deleruyelle, Bertrand Vilquin, Jordan Bouaziz
This study demonstrates the effectiveness of AFE-PUND, a revisited Positive Up Negative Down (PUND) protocol for characterizing antiferroelectric (AFE) materials, in analyzing \(ZrO_2\) films across different thicknesses, revealing key trends. The proposed AFE-PUND method enables the isolation of switching currents from non-switching contributions, allowing precise extraction of remanent polarization and coercive field from hysteresis loops. The remanent polarization increases with film thickness, reflecting enhanced domain stability, while endurance cycles highlight the wake-up effect and its eventual degradation due to fatigue in thicker films. Similarly, coercive fields decrease with thickness, indicating reduced switching barriers and a clearer transition between tetragonal and orthorhombic phases. The method provides valuable insights into micro-structural influences, such as defect accumulation, grain size, and domain wall pinning, which critically affect device performance. AFE-PUND thus establishes itself as an essential tool for advancing the understanding and optimization of antiferroelectric materials.
Materials Science (cond-mat.mtrl-sci)
Self-diffusion in isotropic and liquid crystalline phases of fd virus colloidal rods: a combined single particle tracking and differential dynamic microscopy study
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
Eric Grelet, Vincent A. Martinez, Jochen Arlt
In this article, we investigate the dynamics of self-organised suspensions formed by rod-like fd virus colloids. Two methods have been employed for analysing fluorescence microscopy movies: single particle tracking (SPT) in direct space and differential dynamic microscopy (DDM) in reciprocal space. We perform a quantitative analysis on this anisotropic system with complex diffusion across different self-assembled states, ranging from dilute and semi-dilute liquids to nematic and smectic organisations. By leveraging the complementary strengths of SPT and DDM, we provide new insights in the dynamics of viral colloidal rods, such as long time diffusion coefficients in the smectic phase. We further discuss the advantages and limitations of both methods for studying the intricate dynamics of anisotropic colloidal systems.
Soft Condensed Matter (cond-mat.soft)
Soft Matter, 21, 304 (2025)
Correlated Hopf insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
Konstantinos Ladovrechis, Shouvik Sur
Hopf insulators represent an exceptional class of topological matter unanticipated by the periodic table of topological invariants. These systems point to the existence of previously unexplored states of matter with unconventional topology. In this work, we take a step toward exploring this direction by investigating correlation-driven instabilities of Hopf insulators. Organizing our analysis around the topological quantum critical point that separates the Hopf insulating phase from a trivial insulator, we demonstrate the emergence of unconventional Weyl semimetallic and topological insulating states. Notably, the Weyl semimetal supports non-reciprocal superconductivity and a Bogoliubov-Fermi surface, potentially providing a novel framework for realizing the superconducting diode effect. Finally, we highlight the interconnectedness of the effective descriptions of correlated Hopf insulators, two-dimensional quadratic band-touching semimetals, and Luttinger semimetals.
Strongly Correlated Electrons (cond-mat.str-el), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
13 pages, 11 figures
Self-propulsion and self-rotation of an inertial chiral active Ornstein-Uhlenbeck particle
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
We investigate the transport feature of an inertial chiral active Ornstein-Uhlenbeck particle moving on a two-dimensional surface. Using both analytical approach and numerical simulations, we have exactly explored the transient and steady-state behavior of the particle by analyzing the simulated particle trajectories, probability distribution functions for position and velocity, mean square displacement, mean square velocity, and effective kinetic temperature of the medium. From the mean square displacement calculations, we observe that, unlike an inertial active Brownian particle, a chiral active particle manifests an initial ballistic, intermediate sub-diffusive to non-diffusive, and the conventional long-time diffusive behavior. The intermediate sub-diffusive to non-diffusive behavior is prominent for the self-propulsion of an overdamped particle. It can be understood by chirality-induced transient confinement, which persists for short time intervals and diffuses away in the time asymptotic limit or at the steady state. This behavior is further complemented by the exact calculation of mean square velocity or effective kinetic temperature of the medium, which is a decreasing function of the magnitude of chirality. Moreover, the steady-state MSD and MSV are found to have a dependence both on chirality and activity time scale and hence can be controlled by tuning the persistent duration of activity or strength of the chirality of the particle.
Soft Condensed Matter (cond-mat.soft)
9 pages, 8 figures
Analytical control of the exchange interaction in periodically driven Mott insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-01-10 20:00 EST
The manipulation of electronic structure through periodic electric fields enables the reversible control of effective interactions in extended antiferromagnetic Mott insulators on ultrafast timescales. A careful analytical examination of the modulated effective interactions is conducted, accurately characterising it through the use of exact summation formulas and Bessel functions. As a result, time reversals are analytically determined in terms of Bessel zeroes. We discuss the half-filled Hubbard model, as well as multi-orbital models, various characteristics of the Kitaev-Heisenberg model, and the emergence of chiral spin terms.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
14 pages (including Supplementary Material), 7 figures
Caroli-de Gennes-Matricon Analogs in Full-Shell Hybrid Nanowires
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-01-10 20:00 EST
M. T. Deng, Carlos Payá, Pablo San-Jose, Elsa Prada, C. M. Marcus, S. Vaitiekėnas
We report tunneling spectroscopy of Andreev subgap states in hybrid nanowires with a thin superconducting full-shell surrounding a semiconducting core. The combination of the quantized fluxoid of the shell and the Andreev reflection at the superconductor-semiconductor interface gives rise to analogs of Caroli-de Gennes-Matricon (CdGM) states found in Abrikosov vortices in type-II superconductors. Unlike in metallic superconductors, CdGM analogs in full-shell hybrid nanowires manifest as one-dimensional van Hove singularities with energy spacings comparable to the superconducting gap and independent of the Fermi energy, making them readily observable. Evolution of these analogs with axial magnetic field, skewed within the Little-Parks lobe structure, is consistent with theory and yields information about the radial distribution and angular momenta of the corresponding subbands.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
5 pages, 4 figures
Active Microrheology and Dynamic Phases for Pattern Forming Systems with Competing Interactions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-01-10 20:00 EST
C. Reichhardt, C.J.O. Reichhardt
We consider the driven dynamics of a probe particle moving through an assembly of particles with competing long-range repulsive and short-range attractive interactions, which form crystal, stripe, labyrinth, and bubble states as the ratio of attraction to repulsion is varied. We show that the probe particle exhibits a depinning-like threshold from an elastic regime, where the probe particle is trapped by interactions with the other particles, to a plastic flow regime, where the probe particle can break bonds in the surrounding medium. For a fixed particle density, the depinning threshold and sliding velocity of the probe particle vary nonmonotonically as the attraction term is increased. A velocity minimum appears near the crystal to stripe crossover, and there is a significant increase in the depinning threshold in the bubble regime when the probe particle is strongly confined inside the bubbles. For fixed attractive interaction but increasing particle density, the behavior is also nonmonotonic and there are jumps and drops in the velocity and depinning threshold corresponding to points at which the system transitions between different structures. There are also several distinct flow states that can be characterized by the amount of plastic deformation induced by the probe particle in the surrounding medium. Each flow state generates a different amount of effective drag on the probe particle, and there can be jumps in the velocity-force curve at transitions between the states. We also find that when oriented stripes are present, the probe particle can move along the stripe in an edge transport state that has a finite Hall angle.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
12 pages, 17 figures
How quantum selection rules influence the magneto-optical effects of driven, ultrafast magnetization dynamics
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-01-10 20:00 EST
Mohamed F. Elhanoty, Olle Eriksson, Chin Shen Ong, Oscar Grånäs
Ultrafast magnetization dynamics driven by ultrashort pump lasers is typically explained by changes in electronic populations and scattering pathways of excited conduction electrons. This conventional approach overlooks the fundamental role of quantum mechanical selection rules, governing transitions from core states to the conduction band, that forms the key method of the probing step in these experiments. By employing fully time-dependent density functional theory, we reveal that these selection rules profoundly influence the interpretation of ultrafast spin dynamics at specific probe energies. Our analysis for hcp Co and fcc Ni at the M edge demonstrates that the transient dynamics, as revealed in pump-probe experiments, arise from a complex interplay of optical excitations of the M shell. Taking into account the selection rules and conduction electron spin flips, this leads to highly energy-dependent dynamics. These findings address longstanding discrepancies in experimental TMOKE measurements and show that only through meticulous consideration of matrix elements at the probe stage, can one ensure that magnetization dynamics is revealed in its true nature, instead of being muddled by artifacts arising from the choice of probe energy.
Materials Science (cond-mat.mtrl-sci)
Interplay between altermagnetism and topological superconductivity in an unconventional superconducting platform
New Submission | Superconductivity (cond-mat.supr-con) | 2025-01-10 20:00 EST
Pritam Chatterjee, Vladimir Juričić
We propose a theoretical model to investigate the interplay between altermagnetism and \(p\)-wave superconductivity, with a particular focus on topological phase transitions in a two-dimensional (2D) \(p\)-wave superconductor, considering both chiral and helical phases. Our study reveals that the emergence of helical and chiral Majorana states can be tuned by the amplitude of a \(d-\)wave altermagnetic order parameter, with the outcome depending on the nature of the superconducting state. In the helical superconductor, such an altermagnet can induce a topological phase transition into a gapless topological superconductor hosting Majorana flat edge modes (MFEMs). On the other hand, in the chiral superconductor, the topological transition takes place between a topologically nontrivial gapped phase and a gapless nodal-line superconductor, where the Bogoliubov quasiparticle bands intersect at an isolated line in momentum space. Remarkably, we show that when such an altermagnet is coupled to a mixed-pairing superconductor, with both chiral and helical components, a hybrid topological phase emerges, featuring dispersive Majorana edge that modes coexist with nearly flat Majorana edge states. Our findings therefore establish a novel platform for controlling and manipulating Majorana modes in unconventional superconductors with vanishing total magnetization.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 6 figures