CMP Journal 2025-02-20
Statistics
Nature: 2
Nature Nanotechnology: 2
Physical Review Letters: 16
Physical Review X: 2
arXiv: 72
Nature
Structural dynamics of human fatty acid synthase in the condensing cycle
Original Paper | Cryoelectron microscopy | 2025-02-19 19:00 EST
Wooyoung Choi, Chengmin Li, Yifei Chen, Yongqiang Wang, Yifan Cheng
Long chain fatty acids are the building blocks of fat in human bodies. In mammals, fatty acid synthase (FASN) contains multiple enzymatic domains to catalyze all chemical reactions needed for de novo fatty acid synthesis1. While the chemical reactions carried out by these enzymatic domains are well defined, how the dimeric FASN with an open architecture continuously catalyzes such reactions to synthesize a complete fatty acid remains elusive. Here, using a strategy of tagging and purifying endogenous FASN in HEK293 for single particle cryogenic electron microscopy studies, we characterized the structural dynamics of endogenous human FASN. We captured the conformational snapshots of various functional substates in the condensing cycle and developed a procedure to analyze particle distribution landscape of FASN with different orientations between its condensing and modifying wings. Together, we reveal that FASN function does not require large rotational motion between its two major functional domains during the condensing cycle, and that the catalytic reactions in condensing cycle carried out by two monomers are unsynchronized. Our data thus provide a new composite view of FASN dynamics during the fatty acid synthesis condensing cycle.
Cryoelectron microscopy, Multienzyme complexes
Snapshots of acyl carrier protein shuttling in human fatty acid synthase
Original Paper | Cryoelectron microscopy | 2025-02-19 19:00 EST
Kollin Schultz, Pedro Costa-Pinheiro, Lauren Gardner, Laura V. Pinheiro, Julio Ramirez-Solis, Sarah M. Gardner, Kathryn E. Wellen, Ronen Marmorstein
The mammalian fatty acid synthase (FASN) enzyme is a dynamic multienzyme that belongs to the megasynthase family. In mammals, a single gene encodes six catalytically active domains and a flexibly tethered acyl carrier protein (ACP) domain that shuttles intermediates between active sites for fatty acid biosynthesis1. FASN is an essential enzyme in mammalian development through the role that fatty acids have in membrane formation, energy storage, cell signalling and protein modifications. Thus, FASN is a promising target for treatment of a large variety of diseases including cancer, metabolic dysfunction-associated fatty liver disease, and viral and parasite infections2,3. The multi-faceted mechanism of FASN and the dynamic nature of the protein, in particular of the ACP, have made it challenging to understand at the molecular level. Here we report cryo-electron microscopy structures of human FASN in a multitude of conformational states with NADPH and NADP+ plus acetoacetyl-CoA present, including structures with the ACP stalled at the dehydratase (DH) and enoyl-reductase (ER) domains. We show that FASN activity in vitro and de novo lipogenesis in cells is inhibited by mutations at the ACP-DH and ACP-ER interfaces. Together, these studies provide new molecular insights into the dynamic nature of FASN and the ACP shuttling mechanism, with implications for developing improved FASN-targeted therapeutics.
Cryoelectron microscopy, Enzyme mechanisms, Metabolic pathways
Nature Nanotechnology
Grover's algorithm in a four-qubit silicon processor above the fault-tolerant threshold
Original Paper | Quantum dots | 2025-02-19 19:00 EST
I. Thorvaldson, D. Poulos, C. M. Moehle, S. H. Misha, H. Edlbauer, J. Reiner, H. Geng, B. Voisin, M. T. Jones, M. B. Donnelly, L. F. Peña, C. D. Hill, C. R. Myers, J. G. Keizer, Y. Chung, S. K. Gorman, L. Kranz, M. Y. Simmons
Spin qubits in silicon are strong contenders for the realization of a practical quantum computer. Single- and two-qubit gates have shown fidelities above the fault-tolerant threshold, and entanglement of three qubits has been achieved. Furthermore, high-fidelity operation of two-qubit algorithms is possible. Here we implement a four-qubit silicon processor with all control fidelities above the fault-tolerant threshold. We demonstrate a three-qubit Grover's search algorithm with a ~95% probability of finding the marked state. To this end, we fabricate the processor from three phosphorus atoms precision-patterned into isotopically pure silicon. We define three phosphorus nuclear spin qubits and one electron spin qubit. The long coherence times of the qubits enable single-qubit fidelities above 99.9% for all qubits. Moreover, the efficient single-pulse multi-qubit operation enabled by the electron-nuclear hyperfine interaction facilitates controlled-Z gates with above 99% fidelity between all pairs of nuclear spins when using the electron as an ancilla. These control fidelities, combined with high-fidelity non-demolition readout of all nuclear spins, allows the creation of a three-qubit Greenberger-Horne-Zeilinger state with 96.2% fidelity. Looking ahead, coupling neighbouring nuclear spin registers, as the one shown here, via electron-electron exchange may enable larger, yet fault-tolerant, quantum processors.
Quantum dots, Quantum information, Qubits
Intracellular dehydrogenation catalysis leads to reductive stress and immunosuppression
Original Paper | Catalysis | 2025-02-19 19:00 EST
Jie Jiang, Huizhen Zheng, Zhenzhen Wang, Xinlian Wang, Qianqian Xie, Xi Liu, Qing Yang, Xiaoming Cai, Xingfa Gao, Ruibin Li, Chunying Chen
Imbalanced redox homeostasis, involving either oxidative stress or reductive stress, can profoundly impact cellular functions, contributing to various diseases. While the implications of oxidative stress in the adverse effects of nanoparticles have been extensively studied, our comprehension of reductive stress within the context of nano-redox system interactions remains limited. Here we illuminate a domino effect initiated by the dehydrogenase-like activity of transition metal borides. Specifically, seven transition metal borides were identified to emulate the enzymatic activity of natural dehydrogenases, resulting in heightened levels of reductive constituents within critical biological redox pairs in cells. Mass cytometry analysis provides compelling evidence that reductive stress initiates an immunosuppressive environment within lung tissues, promoting the metastasis of breast cancer cells to the lungs. In summary, our study unveils the chemical basis of nano-induced reductive stress and establishes a mechanistic axis that interlinks dehydrogenase-like activity, reductive stress, immunosuppression and tumour metastasis.
Catalysis, Nanotoxicology
Physical Review Letters
Demonstrating Experimentally the Encoding and Dynamics of an Error-Correctable Logical Qubit on a Hyperfine-Coupled Nuclear Spin Qudit
Research article | Quantum error correction | 2025-02-20 05:00 EST
Sumin Lim, Mikhail V. Vaganov, Junjie Liu, and Arzhang Ardavan
The realization of effective quantum error correction protocols remains a central challenge in the development of scalable quantum computers. Employing high-dimensional quantum systems (qudits) can offer more hardware-efficient protocols than qubit-based approaches. Using electron-nuclear double resonance, we implement a logical qubit encoded on the four states of a \(I=3/2\) nuclear spin hyperfine-coupled to an \(S=1/2\) electron spin qubit; the encoding protects against the dominant decoherence mechanism in such systems, i.e., fluctuations of the quantizing magnetic field. We explore the dynamics of the encoded state both under a controlled application of the fluctuation and under natural decoherence processes. Our results confirm the potential of these proposals for practical, implementable, fault-tolerant quantum memories.
Phys. Rev. Lett. 134, 070603 (2025)
Quantum error correction, Quantum state transfer, Electron nuclear double resonance, Electron paramagnetic resonance
Gate-Based Quantum Simulation of Gaussian Bosonic Circuits on Exponentially Many Modes
Research article | Quantum algorithms & computation | 2025-02-20 05:00 EST
Alice Barthe, M. Cerezo, Andrew T. Sornborger, Martín Larocca, and Diego García-Martín
We introduce a framework for simulating, on an (\(n+1\))-qubit quantum computer, the action of a Gaussian bosonic (GB) circuit on a state over \({2}^{n}\) modes. Specifically, we encode the initial bosonic state's expectation values over quadrature operators (and their covariance matrix) as an input qubit state. This is then evolved by a quantum circuit that effectively implements the symplectic propagators induced by the GB gates. We find families of GB circuits and initial states leading to efficient quantum simulations. For this purpose, we introduce a dictionary that maps between GB and qubit gates such that particle- (non-particle-) preserving GB gates lead to real- (imaginary-) time evolutions at the qubit level. For the special case of particle-preserving circuits, we present a bounded-error-quantum-polynomial time (BQP)-complete GB decision problem, indicating that GB evolutions of Gaussian states on exponentially many modes are as powerful as universal quantum computers. We also perform numerical simulations of an interferometer on \(\sim 8\times{}{10}^{9}\) modes, illustrating the power of our framework.
Phys. Rev. Lett. 134, 070604 (2025)
Quantum algorithms & computation, Quantum circuits, Quantum harmonic oscillator, Computational complexity
Optimal Control in Large Open Quantum Systems: The Case of Transmon Readout and Reset
Research article | Open quantum systems & decoherence | 2025-02-20 05:00 EST
Ronan Gautier, Élie Genois, and Alexandre Blais
We present a framework that combines the adjoint-state method together with reverse-time backpropagation to solve prohibitively large open-system quantum control problems. Our approach enables the optimization of arbitrary cost functions with fully general controls applied on large open quantum systems described by a Lindblad master equation. It is scalable, computationally efficient, and has a low-memory footprint. We apply this framework to optimize two inherently dissipative operations in superconducting qubits which lag behind in terms of fidelity and duration compared to other unitary operations: the dispersive readout and all-microwave reset of a transmon qubit. Our results show that while standard pulses for dispersive readout are nearly optimal, adding a transmon drive during the protocol can yield \(2\times{}\) improvements in fidelity and duration. We further demonstrate a \(2\times{}\) improvement in reset fidelity and duration through pulse shaping, indicating significant potential for enhancement in reset protocols. Our approach can readily be applied to optimize quantum controls in a vast range of applications such as reservoir engineering, autonomous quantum error correction, and leakage-reduction units.
Phys. Rev. Lett. 134, 070802 (2025)
Open quantum systems & decoherence, Quantum control, Quantum information processing, Quantum information with solid state qubits, Superconducting qubits
Optical Quantum Memory on Macroscopic Coherence
Research article | Optical quantum information processing | 2025-02-20 05:00 EST
S. A. Moiseev, K. I. Gerasimov, M. M. Minnegaliev, and E. S. Moiseev
We propose a quantum memory based on the precreated long-lived macroscopic quantum coherence. It is shown that the proposed approach provides new physical properties and methods for retrieval of the signal light fields and improvement of the basic parameters of quantum memory. We demonstrate how the precreated coherence can enable quantum storage with low quantum noise and programmable and on demand retrieval of signal light fields in atomic ensembles with natural inhomogeneous broadening. The feasibility of implementing this proposal in various crystals doped with rare earth ions, as well as in atomic gases with a Raman transition indicates, a new way for the development of optical quantum memory.
Phys. Rev. Lett. 134, 070803 (2025)
Optical quantum information processing, Quantum coherence & coherence measures, Quantum communication, protocols & technology, Quantum information processing, Quantum memories, Quantum protocols, Quantum state transfer
Search for MeV-Scale Axionlike Particles and Dark Photons with PandaX-4T
Research article | Dark matter direct detection | 2025-02-20 05:00 EST
Tao Li et al. (PandaX Collaboration)
Axionlike particles (ALPs) and dark photons (DPs) are viable dark matter particle candidates. We have searched for possible ALP/DP signals in the PandaX-4T liquid xenon detector using \(440\text{ }\text{ }\mathrm{kg}\cdot{}\mathrm{yr}\) of data. A binned likelihood fit is constructed to search for possible mono-energetic peaks induced by the absorption processes between ALPs/DPs and atomic electrons of xenon. A detailed temporal model of decays associated with xenon isotopes is introduced to constrain the number of background events. No signal excess over background expectations is observed, and we have established the most stringent exclusion limits for most ALP/DP masses across the range of \(150\text{ }\text{ }\mathrm{keV}/{c}^{2}\) to \(1\text{ }\text{ }\mathrm{MeV}/{c}^{2}\). The improvement is particularly significant within the mass range of \(150--400\text{ }\text{ }\mathrm{keV}/{c}^{2}\), with the average factor of 3.5 compared to previous results.
Phys. Rev. Lett. 134, 071004 (2025)
Dark matter direct detection, Particle dark matter
Resummation of Threshold Double Logarithms in Hadroproduction of Heavy Quarkonium
Research article | Hadron production | 2025-02-20 05:00 EST
Hee Sok Chung, U-Rae Kim, and Jungil Lee
We resum threshold double logarithms that appear in inclusive production of heavy quarkonium. This resolves the catastrophic failure of fixed-order perturbation theory where quarkonium cross sections at large transverse momentum can turn negative due to large radiative corrections. We find that resummation is imperative for describing measured prompt production rates of $J/$ at large transverse momentum.
Phys. Rev. Lett. 134, 071902 (2025)
Hadron production, Nonrelativistic QCD, Quantum chromodynamics, Resummation methods, Quarkonia
Lattice QCD Calculation of the Subtraction Function in Forward Compton Amplitude
Research article | Compton scattering | 2025-02-20 05:00 EST
Yang Fu, Xu Feng, Lu-Chang Jin, Chuan Liu, and Shi-Da Wen
The subtraction function plays a pivotal role in calculations involving the forward Compton amplitude, which is crucial for predicting the Lamb shift in muonic atoms, as well as the proton-neutron mass difference. In this Letter, we present a lattice QCD calculation of the subtraction function using two domain wall fermion gauge ensembles near the physical pion mass. We utilize a recently proposed subtraction point, demonstrating its advantage in mitigating statistical and systematic uncertainties by eliminating the need for ground-state subtraction. Our results reveal significant contributions from $N$ intermediate states to the subtraction function. Incorporating these contributions, we compute the proton, neutron, and nucleon isovector subtraction functions at photon momentum transfer \({Q}^{2}\in [0,2]\text{ }\text{ }{\mathrm{GeV}}^{2}\). For the proton subtraction function, we compare our lattice results with chiral perturbation theory prediction at low \({Q}^{2}\) and with the results from the perturbative operator-product expansion at high \({Q}^{2}\). Finally, using these subtraction functions as input, we determine their contribution to two-photon exchange effects in the Lamb shift and isovector nucleon electromagnetic self-energy.
Phys. Rev. Lett. 134, 071903 (2025)
Compton scattering, Lattice QCD, Muonic atoms & molecules, Ab initio calculations
Motional Sideband Asymmetry of a Solid-State Mechanical Resonator at Room Temperature
Research article | Light-matter interaction | 2025-02-20 05:00 EST
Yi Xia, Guanhao Huang, Alberto Beccari, Alessio Zicoschi, Amirali Arabmoheghi, Nils J. Engelsen, and Tobias J. Kippenberg
The motional sideband asymmetry of a mechanical oscillator interacting with a laser field can be observed when approaching the quantum ground state, where the zero-point energy of the mechanical oscillator becomes a sizable contribution to its motion. In the context of quantum optomechanics, it allows, in principle, calibration-free inference of the thermal equilibrium of a macroscopic mechanical resonator with its optical bath. At room temperature, this phenomenon has been observed in pioneering experiments using levitated nanoparticles. Measuring this effect with solid-state mechanical resonators has been compounded by thermal intermodulation noise, mirror frequency noise and low quantum cooperativity. Here, we sideband-cool a membrane-in-the-middle system close to the quantum ground state from room temperature and observe motional sideband asymmetry in a dual-homodyne measurement. Sideband thermometry yields a minimum phonon occupancy of \({\overline{n}}_{\mathrm{eff}}=9.5\). Our work provides insights into nonlinear optomechanical dynamics at room temperature and facilitates accessible optomechanical quantum technologies without the need for complex feedback control and cryogenic cooling.
Phys. Rev. Lett. 134, 073602 (2025)
Light-matter interaction, Optomechanics, Micromechanical & nanomechanical oscillators, Cooling & trapping, Homodyne & heterodyne detection
Spatiotemporal Steering of Nondiffracting Wave Packets
Research article | Classical optics | 2025-02-20 05:00 EST
Haiwen Wang, Cheng Guo, and Shanhui Fan
We study the dynamics of space-time nondiffracting wave packets, commonly known as light bullets, in a spatiotemporally varying medium. We show that by spatiotemporal refraction, a monochromatic focused beam can be converted to a light bullet that propagates at a given velocity. By further designing the index profile of the spatiotemporal boundary, the group velocity and the propagation direction of the light bullet can be engineered in a programmable way. All effects mentioned above cannot be achieved by spatial or temporal boundaries, and are only possible with spatiotemporal boundaries. These findings provide unique ways to engineer the dynamics of electromagnetic wave packets in space-time. Such wave packets with engineered space-time trajectory may find potential applications in the spatiotemporal control of material properties or particles, or for use as a way to emulate relativistic physics in the laboratory.
Phys. Rev. Lett. 134, 073803 (2025)
Classical optics, Geometrical & wave optics, Light propagation, transmission & absorption, Light-matter interaction, Metamaterials
Contact Angle Measurements of the Apparent Line Tension Are Spurious
Research article | Contact line dynamics | 2025-02-20 05:00 EST
Beng Hau Tan and Hongjie An
Phenomena in diverse contexts such as wetting, biological assembly, and manufacturing are attributed to the three-phase line tension. However, decades of line tension estimates based on contact angles of droplets controversially span 6 orders of magnitude, raising the question of which measurements are authoritative. Here, we show with experiments and calculations that contact angles fail to estimate line tension regardless of length scale, technique, and measurement quality. Line tension measurements based on contact angles are driven by two distinct and spurious mechanisms: body forces under ideal conditions, and data scatter under noisy conditions.
Phys. Rev. Lett. 134, 074001 (2025)
Contact line dynamics, Drop & bubble phenomena, Surface & interfacial phenomena, Surface tension effects, Drops & bubbles
Layer-Dependent Charge-State Lifetime of Single Se Vacancies in \({\mathrm{WSe}}_{2}\)
Research article | Charge dynamics | 2025-02-20 05:00 EST
Laric Bobzien, Jonas Allerbeck, Nils Krane, Andres Ortega-Guerrero, Zihao Wang, Daniel E. Cintron Figueroa, Chengye Dong, Carlo A. Pignedoli, Joshua A. Robinson, and Bruno Schuler
Defect engineering in two-dimensional semiconductors has been exploited to tune the optoelectronic properties and introduce new quantum states in the band gap. Chalcogen vacancies in transition metal dichalcogenides in particular have been found to strongly impact charge carrier concentration and mobility in 2D transistors as well as feature subgap emission and single-photon response. In this Letter, we investigate the layer-dependent charge-state lifetime of Se vacancies in \({\mathrm{WSe}}_{2}\). In one monolayer \({\mathrm{WSe}}_{2}\), we observe ultrafast charge transfer from the lowest unoccupied orbital of the top Se vacancy to the graphene substrate within \((1\pm{}0.2)\text{ }\text{ }\mathrm{ps}\) measured via the current saturation in scanning tunneling approach curves. For Se vacancies decoupled by transition metal dichalcogenide (TMD) multilayers, we find a subexponential increase of the charge lifetime from \((62\pm{}14)\text{ }\text{ }\mathrm{ps}\) in bilayer to a few nanoseconds in four-layer \({\mathrm{WSe}}_{2}\), alongside a reduction of the defect state binding energy. Additionally, we attribute the continuous suppression and energy shift of the \(dI/dV\) in-gap defect state resonances at very close tip-sample distances to a current saturation effect. Our results provide a key measure of the layer-dependent charge transfer rate of chalcogen vacancies in TMDs.
Phys. Rev. Lett. 134, 076201 (2025)
Charge dynamics, Coulomb blockade, Defects, Density of states, Electron relaxation, Spin-orbit coupling, Layered semiconductors, Transition metal dichalcogenides, Scanning tunneling microscopy, Scanning tunneling spectroscopy
Mott Transition and Volume Law Entanglement with Neural Quantum States
Research article | Metal-insulator transition | 2025-02-20 05:00 EST
Chloé Gauvin-Ndiaye, Joseph Tindall, Javier Robledo Moreno, and Antoine Georges
The interplay between delocalization and repulsive interactions can cause electronic systems to undergo a Mott transition between a metal and an insulator. Here we use neural network hidden fermion determinantal states (HFDS) to uncover this transition in the disordered, fully connected Hubbard model. While dynamical mean-field theory (DMFT) provides exact solutions to physical observables of the model in the thermodynamic limit, our method allows us to directly access the wave function for finite system sizes well beyond the reach of exact diagonalization. We demonstrate how HFDS are able to obtain more accurate results in the metallic regime and in the vicinity of the transition than calculations based on a matrix product state (MPS) ansatz, for which the volume law of entanglement exhibited by the system is prohibitive. We use the HFDS method to calculate the energy and double occupancy, the quasiparticle weight and the energy gap and, importantly, the amplitudes of the wave function that provide a novel insight into this model. Our work paves the way for the study of strongly correlated electron systems with neural quantum states.
Phys. Rev. Lett. 134, 076502 (2025)
Metal-insulator transition, Artificial neural networks, Strongly correlated systems, Dynamical mean field theory, Hubbard model, Machine learning, Tensor network methods
Higher Landau-Level Analogs and Signatures of Non-Abelian States in Twisted Bilayer \({\mathrm{MoTe}}_{2}\)
Research article | Topological phases of matter | 2025-02-20 05:00 EST
Chong Wang, Xiao-Wei Zhang, Xiaoyu Liu, Jie Wang, Ting Cao, and Di Xiao
Recent experimental discovery of fractional Chern insulators at zero magnetic field in moir'e superlattices has sparked intense interests in bringing Landau level physics to flat Chern bands. In twisted \({\mathrm{MoTe}}_{2}\) bilayers (\({\mathrm{tMoTe}}_{2}\)), recent theoretical and experimental studies have found three consecutive flat Chern bands at twist angle \(\sim 2^\circ{}\). In this Letter, we investigate whether higher Landau level physics can be found in these consecutive Chern bands. At twist angles 2.00^ and 1.89^, we identify four consecutive \(C=1\) bands for the \(K\) valley in \({\mathrm{tMoTe}}_{2}\). By constructing Wannier functions directly from density functional theory (DFT) calculations, a six-orbital model is developed to describe the consecutive Chern bands, with the orbitals forming a honeycomb lattice. Exact diagonalization on top of Hartree-Fock calculations are carried out with the Wannier functions. Especially, when the second moir'e miniband is half-filled, signatures of non-Abelian states are found. Our Wannier-based approach in modeling moir'e superlattices is faithful to DFT wave functions and can serve as benchmarks for continuum models. The possibility of realizing non-Abelian anyons at zero magnetic field also opens up a new pathway for fault-tolerant quantum information processing.
Phys. Rev. Lett. 134, 076503 (2025)
Topological phases of matter, Strongly correlated systems, Transition metal dichalcogenides, Twisted heterostructures, Exact diagonalization
Paradigm for Finding \(d\)-Electron Heavy Fermions: The Case of Cr-doped \({\mathrm{CsFe}}_{2}{\mathrm{As}}_{2}\)
Research article | Heavy-fermion systems | 2025-02-20 05:00 EST
Matteo Crispino, Pablo Villar Arribi, Anmol Shukla, Frédéric Hardy, Amir-Abbas Haghighirad, Thomas Wolf, Rolf Heid, Michael Merz, Christoph Meingast, Tommaso Gorni, Adolfo Avella, and Luca de' Medici
A new strategy allows scientists to find and make materials that host so-called heavy electrons without requiring rare-earth or actinide elements.
Phys. Rev. Lett. 134, 076504 (2025)
Heavy-fermion systems, Iron-based superconductors, Strongly correlated systems
Infrared Magnetopolaritons in \({\mathrm{MoTe}}_{2}\) Monolayers and Bilayers
Research article | Excitons | 2025-02-20 05:00 EST
Bo Han, Jamie M. Fitzgerald, Lukas Lackner, Roberto Rosati, Martin Esmann, Falk Eilenberger, Takashi Taniguchi, Kenji Watanabe, Marcin Syperek, Ermin Malic, and Christian Schneider
Magneto-optical studies of exciton polaritons in monolayer and bilayer MoTe2 show strong coupling and exciton-polariton resonances close to the telecom window.
Phys. Rev. Lett. 134, 076902 (2025)
Excitons, Magneto-optics, Methods in magnetism, Phonons, Polaritons, Valley degrees of freedom, Valleytronics
Geometrically Frustrated, Mechanical Metamaterial Membranes: Large-Scale Stress Accumulation and Size-Selective Assembly
Research article | Elasticity | 2025-02-20 05:00 EST
Michael Wang, Sourav Roy, Christian Santangelo, and Gregory Grason
We study the effect of geometric frustration on dilational mechanical metamaterial membranes. While shape frustrated elastic plates can only accommodate nonzero Gaussian curvature up to size scales that ultimately vanish with their elastic thickness, we show that frustrated metamembranes accumulate hyperbolic curvatures up to mesoscopic length scales that are ultimately independent of the size of their microscopic constituents. A continuum elastic theory and discrete numerical model describe the size-dependent shape and internal stresses of axisymmetric, trumpetlike frustrated metamembranes, revealing a nontrivial crossover to a much weaker power-law growth in elastic strain energy with size than in frustrated elastic membranes. We study a consequence of this for the self-limiting assembly thermodynamics of frustrated trumpets, showing a severalfold increase in the size range of self-limitation of metamembranes relative to elastic membranes.
Phys. Rev. Lett. 134, 078201 (2025)
Elasticity, Mechanical properties of membranes, Self-assembly, Mechanical metamaterials, Membrane structures
Physical Review X
Sketched Nanoscale \({\mathrm{KTaO}}_{3}\)-Based Superconducting Quantum Interference Device
Research article | Oxides | 2025-02-20 05:00 EST
Muqing Yu, Nicholas Hougland, Qianheng Du, Junyi Yang, Sayanwita Biswas, Ranjani Ramachandran, Dengyu Yang, Anand Bhattacharya, David Pekker, Patrick Irvin, and Jeremy Levy
Potassium tantalate enables superconducting weak links with high, tunable inductance, making it a promising material for quantum devices, and its AFM-based nanoscale patterning offers new possibilities for reconfigurable quantum circuits.
Phys. Rev. X 15, 011037 (2025)
Oxides, SQUID, Superconducting devices, Weak links, Atomic force microscopy, Dilution refrigerator
Anomalous Quasielastic Scattering Contribution in the Centrosymmetric Multi-\(\mathbf{q}\) Helimagnet \({\mathrm{SrFeO}}_{3}\)
Research article | Frustrated magnetism | 2025-02-20 05:00 EST
Nikita D. Andriushin, Justus Grumbach, Anton A. Kulbakov, Yuliia V. Tymoshenko, Yevhen A. Onykiienko, Reza Firouzmandi, Erjian Cheng, Sergey Granovsky, Yurii Skourski, Jacques Ollivier, Helen C. Walker, Vilmos Kocsis, Bernd Büchner, Bernhard Keimer, Mathias Doerr, Dmytro S. Inosov, and Darren C. Peets
SrFeO3, a compound with long-range, helical magnetic order, exhibits unique spin fluctuations that are likely caused by chiral domain walls, making it a valuable material for studying complex magnetic behaviors and spin dynamics.
Phys. Rev. X 15, 011038 (2025)
Frustrated magnetism, Magnetism, Magnons, Phase diagrams, Spin dynamics, Magnetization measurements, Neutron scattering
arXiv
A mechanism for ice growth on the surface of a spherical water droplet
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Yang Li, Prachi Parashar, Iver Brevik, Clas Persson, I. Malyi, Mathias Boström
The formation and growth of ice particles, particularly on the surfaces of spherical water droplets, bear profound implications for localized weather systems and global climate. Herein, we develop a theoretical framework for ice nucleation on minuscule water droplets, establishing that \(10\sim5000\rm\ nm\) droplets can considerably increase in volume, making a substantial contribution to ice formation within mist, fog, or even cloud systems. We reveal that the Casimir-Lifshitz (van der Waals) interaction within these systems is robust enough to stimulate both water and ice growth on the surfaces of ice-cold spherical water droplets. The significant impacts and possible detectable phenomena from the curvature are demonstrated.
Materials Science (cond-mat.mtrl-sci), Statistical Mechanics (cond-mat.stat-mech)
Compositionally Grading Alloy Stacking Fault Energy using Autonomous Path Planning and Additive Manufacturing with Elemental Powders
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
James Hanagan, Nicole Person, Daniel Salas, Marshall Allen, Wenle Xu, Daniel Lewis, Brady Butler, James D. Paramore, George Pharr, Ibrahim Karaman, Raymundo Arroyave
Compositionally graded alloys (CGAs) are often proposed for use in structural components where the combination of two or more alloys within a single part can yield substantial enhancement in performance and functionality. For these applications, numerous design methodologies have been developed, one of the most sophisticated being the application of path planning algorithms originally designed for robotics to solve CGA design problems. In addition to the traditional application to structural components, this work proposes and demonstrates the application of this CGA design framework to rapid alloy design, synthesis, and characterization. A composition gradient in the CoCrFeNi alloy space was planned between the maximum and minimum stacking fault energy (SFE) as predicted by a previously developed model in a face-centered cubic (FCC) high entropy alloy (HEA) space. The path was designed to be monotonic in SFE and avoid regions that did not meet FCC phase fraction and solidification range constraints predicted by CALculation of PHAse Diagrams (CALPHAD). Compositions from the path were selected to produce a linear gradient in SFE, and the CGA was built using laser directed energy deposition (L-DED). The resulting gradient was characterized for microstructure and mechanical properties, including hardness, elastic modulus, and strain rate sensitivity. Despite being predicted to contain a single FCC phase throughout the gradient, part of the CGA underwent a martensitic transformation, thereby demonstrating a limitation of using equilibrium CALPHAD calculations for phase stability predictions. More broadly, this demonstrates the ability of the methods employed to bring attention to blind spots in alloy models.
Materials Science (cond-mat.mtrl-sci)
Accelerated Fatigue Strength Prediction via Additive Manufactured Functionally Graded Materials and High-Throughput Plasticity Quantification
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
C. Bean, M. Calvat, Y. Nie, R.L Black, N. Velisavljevic, D. Anjaria, M.A. Charpagne, J. C. Stinville
Recent improvements in additive manufacturing and high-throughput material synthesis have enabled the discovery of novel metallic materials for extreme environments. However, high-fidelity testing of advanced mechanical properties such as fatigue strength, has often been the most time-consuming and resource-intensive step of material discovery, thereby slowing down the adoption of novel materials. This work presents a new method for rapid characterization of the fatigue properties of many compositions while only testing a single specimen. The approach utilizes high-resolution digital image correlation along with a computer vision model to extract the relationship between localized plastic deformation events and associated mechanical properties. The approach is initially validated on an additive manufactured 316L dataset, then applied to a functionally graded additive manufactured specimen with a composition gradient across the gauge length. This allows for the characterization of multiple compositions, orders of magnitude faster than traditional methods.
Materials Science (cond-mat.mtrl-sci)
Cartesian Nodal Lines and Magnetic Kramers Weyl Nodes in Spin-Split Antiferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Zheng-Yang Zhuang, Di Zhu, Zhigang Wu, Zhongbo Yan
When band degeneracy occurs in a spin-split band structure, it gives rise to divergent Berry curvature and distinctive topological boundary states, resulting in a variety of fascinating effects. We show that three-dimensional spin-split antiferromagnets, characterized by symmetry-constrained momentum-dependent spin splitting and zero net magnetization, can host two unique forms of symmetry-protected band degeneracy: Cartesian nodal lines in the absence of spin-orbit coupling, and magnetic Kramers Weyl nodes when spin-orbit coupling is present. Remarkably, these band degeneracies not only produce unique patterns of Berry-curvature distributions but also give rise to topological boundary states with unconventional spin textures. Furthermore, we find that these band degeneracies can lead to strong or even quantized anomalous Hall effects and quantized circular photogalvanic effects under appropriate conditions. Our study suggests that spin-split antiferromagnets provide a fertile ground for exploring unconventional topological phases.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
5 pages, 4 figures for main text; 9 pages, 2 figures for supplemental materials
Triangular lattice models of the Kalmeyer-Laughlin spin liquid from coupled wires
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
Tingyu Gao, Niklas Tausendpfund, Erik L. Weerda, Matteo Rizzi, David F. Mross
Chiral spin liquids (CSLs) are exotic phases of interacting spins in two dimensions, characterized by long-range entanglement and fractional excitations. We construct a local Hamiltonian on the triangular lattice that stabilizes the Kalmeyer-Laughlin CSL without requiring fine-tuning. Our approach employs coupled-wire constructions and introduces a lattice duality to construct a solvable chiral sliding Luttinger liquid, which is driven towards the CSL phase by generic perturbations. By combining symmetry analysis and bosonization, we make sharp predictions for the ground states on quasi-one-dimensional cylinders and tori, which exhibit a four-fold periodicity in the circumference. Extensive tensor network simulations demonstrating ground state degeneracies, fractional quasi-particles, non-vanishing long-range order parameters, and entanglement signatures confirm the emergence of the CSL in the lattice Hamiltonian.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
23 pages, 26 figures
Intelligent Soft Matter: Towards Embodied Intelligence
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-20 20:00 EST
Vladimir A. Baulin, Achille Giacometti, Dmitry Fedosov, Stephen Ebbens, Nydia R. Varela-Rosales, Neus Feliu, Mithun Chowdhury, Minghan Hu, Rudolf Füchslin, Marjolein Dijkstra, Matan Mussel, René van Roij, Dong Xie, Vassil Tzanov, Mengjie Zu, Samuel Hidalgo-Caballero, Ye Yuan, Luca Cocconi, Cheol-Min Ghim, Cécile Cottin-Bizonne, M. Carmen Miguel, Maria Jose Esplandiu, Juliane Simmchen, Wolfgang J. Parak, Marco Werner, Gerhard Gompper, Martin M. Hanczyc
Intelligent soft matter stands at the intersection of materials science, physics, and cognitive science, promising to change how we design and interact with materials. This transformative field seeks to create materials that possess life-like capabilities, such as perception, learning, memory, and adaptive behavior. Unlike traditional materials, which typically perform static or predefined functions, intelligent soft matter dynamically interacts with its environment. It integrates multiple sensory inputs, retains experiences, and makes decisions to optimize its responses. Inspired by biological systems, these materials intend to leverage the inherent properties of soft matter: flexibility, self-evolving, and responsiveness to perform functions that mimic cognitive processes. By synthesizing current research trends and projecting their evolution, we present a forward-looking perspective on how intelligent soft matter could be constructed, with the aim of inspiring innovations in fields such as biomedical devices, adaptive robotics, and beyond. We highlight new pathways for integrating design of sensing, memory and action with internal low-power operations and discuss challenges for practical implementation of materials with "intelligent behavior". These approaches outline a path towards to more robust, versatile and scalable materials that can potentially act, compute, and "think" by their inherent intrinsic material behaviour beyond traditional smart technologies relying on external control.
Soft Condensed Matter (cond-mat.soft)
Entropy of spatial network with applications to non-extensive statistical mechanics
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-20 20:00 EST
A new method is proposed for analyzing complexity and studying the information in random geometric networks using Tsallis entropy tool. Tsallis entropy of the ensemble of random geometric networks is calculated based on the components of the random connection model on the point process which is obtained by connecting the points with a probability that depends on their relative positions (https://doi.org/10.1016/j.indag.2022.05.002, 2022). According to information theory and conditional discussion, the bounds for Shannon and Tsallis entropies of the ensemble of this random graph are presented. Using this function and Lagrange's formula, the connection function that provides the maximum Tsallis entropy based on general constraints is obtained. Then, a simulation-based example is presented to clarify the application of the proposed method in the study of ad hoc wireless networks. By observing the obtained results, it can be stated that the wireless networks that adhere to the model studied here are almost maximally complex. Also, Tsallis conditional entropy maximizing function is compared with other connection functions using numerical calculations and the optimal value for the maximization of conditional entropies is obtained.
Statistical Mechanics (cond-mat.stat-mech), Probability (math.PR), Other Statistics (stat.OT)
17 pages
Asynchronous mass inversion enriched quantum anomalous Hall states in multilayer graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Xilin Feng, Zi-Ting Sun, K.T.Law
Recently, multilayer graphene systems have attracted significant attention due to the discovery of a variety of intriguing phases, particularly quantum anomalous Hall (QAH) states. In rhombohedral pentalayer graphene, both \(C = -5\) and \(C = -3\) QAH states have been observed. While the \(C = -5\) QAH state is well understood, the origin of the \(C = -3\) QAH state remains unclear. In this letter, we propose that the \(C = -3\) QAH state in rhombohedral pentalayer graphene (RPG) arises from an asynchronous mass inversion mechanism, driven by the interplay between trigonal warping and staggered layer order under an applied displacement field. Trigonal warping splits the low-energy bands into a central touching point and three "leg" Dirac cones. In the presence of staggered layer order, this splitting enables mass inversions driven by the displacement field to occur asynchronously at the central touching point and the "leg" Dirac cones, potentially leading to the formation of the \(C = -3\) QAH state. Furthermore, this mechanism can also be applied to Bernal multilayer graphene systems, predicting the existence of additional QAH states beyond \(C = \pm N, \pm 2N\) for \(N\)-layer graphene.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
Cove-edged Chiral Graphene Nanoribbons with Chirality-Dependent Bandgap and Carrier Mobility
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
K. Liu, W. Zheng, S. Osella, Z. Qiu, S. Böckmann, W. Niu, L. Meingast, H. Komber, S. Obermann, R. Gillen, M. Bonn, M. R. Hansen, J. Maultzsch, H. I. Wang, J. Ma, X. Feng
Graphene nanoribbons (GNRs) have garnered significant interest due to their highly customizable physicochemical properties and potential utility in nanoelectronics. Besides controlling widths and edge structures, the inclusion of chirality in GNRs brings another dimension for fine-tuning their optoelectronic properties, but related studies remain elusive owing to the absence of feasible synthetic strategies. Here, we demonstrate a novel class of cove-edged chiral GNRs (CcGNRs) with a tunable chiral vector (n,m). Notably, the bandgap and effective mass of (n,2)- CcGNR show a distinct positive correlation with the increasing value of n, as indicated by theory. Within this GNR family, two representative members, namely, (4,2)- CcGNR and (6,2)-CcGNR, are successfully synthesized. Both CcGNRs exhibit prominently curved geometries arising from the incorporated [4]helicene motifs along their peripheries, as also evidenced by the single-crystal structures of the two respective model compounds (1 and 2). The chemical identities and optoelectronic properties of (4,2)- and (6,2)-CcGNRs are comprehensively investigated via a combination of IR, Raman, solid-state NMR, UV-vis, and THz spectroscopies as well as theoretical calculations. In line with theoretical expectation, the obtained (6,2)-CcGNR possesses a low optical bandgap of 1.37 eV along with charge carrier mobility of 8 cm2/Vs, whereas (4,2)-CcGNR exhibits a narrower bandgap of 1.26 eV with increased mobility of 14 cm2/Vs. This work opens up a new avenue to precisely engineer the bandgap and carrier mobility of GNRs by manipulating their chiral vector.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
J. Am. Chem. Soc. 2024 146, 1026-1034
Evidence of Replica Symmetry Breaking under the Nishimori conditions in epidemic inference on graphs
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-20 20:00 EST
Alfredo Braunstein, Louise Budzynski, Matteo Mariani, Federico Ricci-Tersenghi
In Bayesian inference, computing the posterior distribution from the data is typically a non-trivial problem, which usually requires approximations such as mean-field approaches or numerical methods, like the Monte Carlo Markov Chain. Being a high-dimensional distribution over a set of correlated variables, the posterior distribution can undergo the notorious replica symmetry breaking transition. When it happens, several mean-field methods and virtually every Monte Carlo scheme can not provide a reasonable approximation to the posterior and its marginals. Replica symmetry is believed to be guaranteed whenever the data is generated with known prior and likelihood distributions, namely under the so-called Nishimori conditions. In this paper, we break this belief, by providing a counter-example showing that, under the Nishimori conditions, replica symmetry breaking arises. Introducing a simple, geometrical model that can be thought of as a patient zero retrieval problem in a highly infectious regime of the epidemic Susceptible-Infectious model, we show that under the Nishimori conditions, there is evidence of replica symmetry breaking. We achieve this result by computing the instability of the replica symmetric cavity method toward the one step replica symmetry broken phase. The origin of this phenomenon -- replica symmetry breaking under the Nishimori conditions -- is likely due to the correlated disorder appearing in the epidemic models.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech), Information Theory (cs.IT), Machine Learning (cs.LG), Physics and Society (physics.soc-ph)
17 pages, 7 figures
Probing Structural Dynamics in Photocatalytic Water Splitting: X-ray vs. Neutron Scattering
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Photocatalytic water splitting represents a pivotal pathway for converting solar energy into chemical energy, with the core challenge lying in the design and optimization of photocatalysts [1] . TiO2, as a quintessential photocatalytic material, undergoes significant alterations in its electronic and crystalline structures under intense light irradiation, which may directly impacts its photocatalytic efficiency [2] . To gain a profound understanding of these transformations, in situ characterization techniques such as X-ray scattering and neutron scattering have emerged as crucial tools. This paper, from a combined perspective of theoretical computation and experimental characterization, explores the differential capabilities of X-ray scattering and neutron scattering in characterizing the pair distribution function (PDF) of materials during photocatalytic water splitting. Furthermore, through simulation calculations, it aims to unveil the changes in the electronic and crystalline structures under intense light irradiation. This initial draft of the paper is subject to subsequent revisions.
Materials Science (cond-mat.mtrl-sci)
Violation of Pauli Limit at KTaO3(110) Interfaces
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
Samuel J. Poage, Xueshi Gao, Merve Baksi, Salva Salmani-Rezaie, David A. Muller, Divine P. Kumah, Chun Ning Lau, Jose Lorenzana, Maria N. Gastiasoro, Kaveh Ahadi
The superconducting order parameter at the KTaO3 interfaces and its dependence on interface orientation remains a subject of debate. The superconductivity at these interfaces exhibits strong resilience against in-plane magnetic field and violates Pauli limit. The interface orientation dependence of critical field and violation of Pauli limit, however, have not been investigated. To address this problem, we grew epitaxial LaMnO3/KTaO3 heterostructures using molecular beam epitaxy. We show that superconductivity is extremely robust against the in-plane magnetic field. Our results indicate that the interface orientation, despite impacting the critical temperature, does not affect the ratio of critical field to the Pauli limiting field. These results offer opportunities to engineer superconductors which are resilient against magnetic field.
Superconductivity (cond-mat.supr-con)
An unusual first order phase transition in a 2D superconductor
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
Noah J. Jabusch, Emmanouil K. Kokkinis, Andrey V. Chubukov
We consider a superconductor under external perturbation, which forces Cooper pairs to develop with a finite total momentum \(q\). The condensation energy of such a state decreases with \(q\) and vanishes at a critical \(q_c\). We analyze how superconducting order evolves at $ q q_c$. In 3D, the result is well-known: the pairing susceptibility diverges at \(q = q_c +0\), and the gap amplitude \(\Delta (q)\) gradually increases as \(q\) decreases below \(q_c\) and reaches its largest value \(\Delta_0\) at \(q=0\). In 2D, we find different behavior. Namely, for a parabolic dispersion, the pairing susceptibility also diverges at \(q = q_c +0\), but at \(q = q_c -0\), the gap amplitude jumps to the maximal \(\Delta_0\) and remains equal to it for all \(q <q_c\). For a non-parabolic dispersion \(\varepsilon_{k}= c k^{2\alpha}\), we find that for \(\alpha>1\) the transition becomes second-order, but the gap evolution is rather sharp, whereas for \(\alpha<1\) it becomes first-order, but \(\Delta (q)\) is non-monotonic. This is similar, but not identical, to the behavior of magnetization near a Stoner transition in 2D.
Superconductivity (cond-mat.supr-con)
26 pages + 9 figures
Uniaxial Pressure Effects, Phase Diagram, and Tricritical Point in the Centrosymmetric Skyrmion Lattice Magnet GdRu\(_2\)Si\(_2\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
L. Gries, T. Kleinbeck, D. A. Mayoh, G. D. A. Wood, G. Balakrishnan, R. Klingeler
The magnetic phase diagram, magnetoelastic coupling, and uniaxial pressure effects of centrosymmetric magnetic skyrmion-hosting GdRu\(_2\)Si\(_2\) are investigated by means of high-resolution capacitance dilatometry in fields up to 15,T supported by specific heat and magnetisation studies. In addition to the previously reported phases in the \(H\)-\(T\) phase diagram, we observe a third antiferromagnetic phase in zero magnetic field. We present the magnetic phase diagram and find two unreported phases, one of which features a comparably giant uniaxial pressure dependence. Our dilatometric measurements show magnetoelastic effects associated with the various magnetic ordering phenomena. We determine the uniaxial pressure dependencies of the various phases, in particular of the skyrmion lattice phase which is enhanced at higher fields and temperatures and also widens at a rate of 0.07~T/GPa when uniaxial pressure is applied along the \(c\) axis. The relevance of fluctuations is further highlighted by the presence of tricritical point indicated by our thermodynamic data at the phase boundary separating two double- magnetic configurations between which the skyrmion pocket phase evolves upon further cooling.
Strongly Correlated Electrons (cond-mat.str-el)
Phys. Rev. B 111, 064419 (2025)
Enhancing Electrical Properties of Selectively Grown In-Plane InAs Nanowires using InGaAs Buffer and Capping Layers
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Pradip Adhikari, Anjali Rathore, Dayrl P Briggs, Srijanto R Bernadeta, Joon Sue Lee
In-plane semiconductor nanowires with complex branched geometries, prepared via selective area growth (SAG), offer a versatile platform for advanced electronics, optoelectronics, and quantum devices. However, defects and disorder at the interfaces and top surfaces of the nanowires can significantly degrade their electrical properties. One effective method to mitigate these issues is the incorporation of buffer and capping layers. In this work, we achieved a wider growth selectivity window of InGaAs in the presence of atomic hydrogen (H) and employed it as buffer and capping layers for SAG InAs nanowires to enhance their electrical properties. Hall measurements on InAs nanowires, with and without InGaAs buffer and/or capping layers, revealed that incorporating closely lattice-matched InGaAs buffer and capping layers to InAs nanowires nearly tripled the electron mobility and doubled the phase coherence length compared to nanowires without these layers. These findings demonstrate that the use of InGaAs buffer and capping layers is a crucial strategy for significantly enhancing the quality of InAs nanowires, unlocking their full potential for high performance electronics and quantum devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Transparent Graphene-Superconductor Interfaces: Quantum Hall and Zero Field Regimes
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Alexey Bondarev, Gu Zhang, Harold U. Baranger
We study clean, edge-contacted graphene/superconductor interfaces in both the quantum Hall (QH) and zero field regimes. We find that Andreev reflection is substantially stronger than at an interface with a semiconductor two-dimensional electron gas: the large velocity at graphene's conical Dirac points makes the requirement of current continuity to a metal much less restrictive. In both our tight-binding and continuum models, we find a wide range of parameters for which Andreev reflection is strong. For a transparent interface, we demonstrate the following for graphene in the lowest Landau level QH state: (i) Excellent electron-hole hybridization occurs: the electron and hole components in graphene are simply related by an exchange of sublattice. The spatial profile for the electron component is predominantly gaussian on one sublattice and peaked at the interface, and so very different from the QH edge state of a terminated lattice. (ii) The degree of hybridization is independent of the graphene filling: no fine-tuning is needed. (iii) The spectrum is valley degenerate: the dispersion of each chiral Andreev edge mode (CAEM) self-aligns to be antisymmetric about the center of each valley, independent of filling. Achieving a transparent interface requires the absence of any barrier as well as a superconductor that is suitably matched to graphene; we argue that the latter condition is not very stringent. We further consider the effect of reduced transparency and Zeeman splitting on both the wavefunctions of the CAEM and their dispersion.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Superconductivity (cond-mat.supr-con)
25 pages, 21 figures
The Effect of Water Contamination on the Aging of a Dual-Carbon Lithium-Ion Capacitor Employing LiFSI-Based Electrolyte
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Philipp Schweigart, Johan Hamonnet, Obinna Egwu Eleri, Laura King, Samson Yuxiu Lai, Ann Mari Svensson
Fabricating electrochemical energy storage devices demands significant energy for drying cell components to ensure optimal performance. The development of new, water-tolerant materials would represent a tremendous advance in cost savings and sustainability. Although it is generally established that water deteriorates cell performance, there are few systematic studies on the maximum amount of tolerable water contamination, and most of the studies employed the electrolyte salt \(\mathrm{LiPF_6}\), which inevitably decomposes upon exposure to humidity. In this work, the potential of using the non-hydrolyzing salt LiFSI is explored with respect to its performance in Li-ion capacitor cells based on activated carbon (AC) and pre-lithiated graphite (Gr). Water is deliberately added in various amounts (950, 2300, and 6000 ppm), and its effect on the electrochemical performance and aging of AC and Gr electrodes is systematically studied. While the addition of 950 ppm water has no evident impact on capacity retention (96% after 2000 cycles), the addition of 2300 ppm water or 6000 ppm water shows a distinct capacity fade, attributed to a significant loss of lithium inventory and increased resistivity due to irreversible reactions of the water with lithiated Gr. Post-mortem analysis reveals that water promotes the oxidative and reductive decomposition of LiFSI on AC and lithiated Gr, respectively. A significant thickening of the SEI on Gr is observed as the water concentration is increased.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph)
Giant Topological Hall Effect Across Wide Temperature in Pt/NiCo2O4 Heterostructure
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Bharat Giri, Ahsan Ullah, Jing Li, Bjorn Josteinsson, Zhewen Xu, Suvechhya Lamichhane, Adam Erickson, Arjun Subedi, Peter A Dowben, Gabriel Puebla Hellmann, Abdelghani Laraoui, Sy-Hwang Liou, Xiaoshan Xu
Topological Hall effect (THE), a quantum phenomenon arising from emergent magnetic field generated by topological spin texture, is a key method for detecting non-coplanar spin structures like skyrmions in magnetic materials. Here, we investigate a bilayer structure of Pt and conducting ferrimagnet NiCo2O4 (NCO) of perpendicular magnetic anisotropy and demonstrate giant THE across a temperature range 2 - 350 K. The absence of THE in single-layer Pt and NCO, as well as in Pt/Cu/NCO, suggests its interfacial origin. The maximum THE occurring just before the NCO coercive field indicates its connection to magnetic nucleation centers, which are topologically equivalent to skyrmions. The large normalized THE, based on the emergent-field model, points to a high population density of small nucleation centers. This aligns with the unresolvable domain structures during magnetization reversal, even though clear domain structures are detected after zero-field cooling. These results establish heavy metal/NCO as a promising system for exploring topological spin structures.
Materials Science (cond-mat.mtrl-sci)
36 pages, 16 figures, submitted to Nano Letters
Fluctuation-driven topological Hall effect in room-temperature itinerant helimagnet Fe3Ga4
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
Priya R. Baral, Victor Ukleev, Ivica Živković, Youngro Lee, Fabio Orlandi, Pascal Manuel, Yurii Skourski, Lukas Keller, Anne Stunault, J. Alberto Rodríguez-Velamazán, Robert Cubitt, Arnaud Magrez, Jonathan S. White, Igor I. Mazin, Oksana Zaharko
The topological Hall effect (THE) is a hallmark of a non-trivial geometric spin arrangement in a magnetic metal, originating from a finite scalar spin chirality (SSC). The associated Berry phase is often a consequence of non-coplanar magnetic structures identified by multiple k-vectors. For single-k magnetic structures however with zero SSC, the emergence of a finite topological Hall signal presents a conceptual challenge. Here, we report that a fluctuation-driven mechanism involving chiral magnons is responsible for the observed THE in a low-symmetry compound, monoclinic Fe3Ga4. Through neutron scattering experiments, we discovered several nontrivial magnetic phases in this system. In our focus is the helical spiral phase at room temperature, which transforms into a transverse conical state in applied magnetic field, supporting a significant THE signal up to and above room temperature. Our work offers a fresh perspective in the search for novel materials with intertwined topological magnetic and transport properties.
Strongly Correlated Electrons (cond-mat.str-el)
20 pages, 4 figures
Heating of a semi-infinite Hooke chain
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-20 20:00 EST
We consider unsteady ballistic heat transport in a semi-infinite Hooke chain with a free end and an arbitrary heat source. An analytical description of the evolution of the kinetic temperature is proposed in both discrete (exact) and continuum (approximate) formulations. The continualization of the discrete solution for kinetic temperature is performed through a large-time asymptotic estimate of the fundamental solution of the dynamical problem for the instantly perturbed conservative semi-infinite chain at the fronts of the incident and reflected thermal waves. By analyzing the continuum solution, we observe that any instantaneous heat supply (i.e., a heat pulse) results in the anti-localization of the reflected thermal wave. We demonstrate that sudden point heat supply leads to a transition to a non-equilibrium steady state, which, unexpectedly, may exist even in the non-dissipative case. The results of this paper are expected to provide insight into the continuum description of nanoscale heat transport.
Statistical Mechanics (cond-mat.stat-mech)
Carbon in GaN as a nonradiative recombination center
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Fangzhou Zhao, Hongyi Guan, Mark E. Turiansky, Chris G. Van de Walle
Trap-assisted nonradiative recombination has been shown to limit the efficiency of optoelectronic devices. While substitutional carbon (\(\mathrm{C_N}\)) has been suggested to be a nonradiative recombination center in GaN devices, a complete recombination cycle including the two charge-state transition levels has not been previously described. In this work, we investigate the trap-assisted recombination process due to \(\mathrm{C_N}\) in GaN, including multiphonon emission (MPE), radiative recombination, trap-assisted Auger-Meitner (TAAM) recombination, as well as thermal emission of holes. Our study shows the key role of TAAM processes at the high carrier densities relevant for devices. We also reveal the carrier-density regimes where thermal emission and radiative recombination are expected to play an observable role. Our results highlight that carbon concentrations exceeding $\(10\)^{17}$ cm\(^{-3}\) can have a noticeable impact on device efficiency, not just in GaN active layers but also in InGaN and AlGaN. Our comprehensive formalism not only offers detailed results for carbon but provides a general framework for assessing the multiple processes that participate in trap-assisted recombination in semiconductors.
Materials Science (cond-mat.mtrl-sci)
Beyond Homes scaling: disorder, the Planckian bound and a new universality
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
D. M. Broun, Vivek Mishra, J. S. Dodge, P. J. Hirschfeld
Beginning with high-\(T_c\) cuprate materials, it has been observed that many superconductors exhibit so-called "Homes scaling", in which the zero-temperature superfluid density, \(\rho_{s0}\), is proportional to the product of the normal-state dc conductivity and the superconducting transition temperature, \(\sigma_\mathrm{dc} T_c\). For conventional, s-wave superconductors, such scaling has been shown to be a natural consequence of elastic-scattering disorder, not only in the extreme dirty limit but across a broad range of scattering parameters. Here we show that when an analogous calculation is carried out for elastic scattering in d-wave superconductors, a stark contrast emerges, with \(\rho_{s0} \propto \left(\sigma_\mathrm{dc} T_c \right)^2\) in the dirty limit, in apparent violation of Homes scaling. Within a simple approximate Migdal--Eliashberg treatment of inelastic scattering, we show how Homes scaling is recovered. The normal-state behavior of near optimally doped cuprates is dominated by inelastic scattering, but significant deviations from Homes scaling occur for disorder-dominated cuprate systems, such as underdoped YBCO and overdoped LSCO, and in very clean materials with little inelastic scattering, such as Sr\(_2\)RuO\(_4\). We present a revised analysis where both axes of the original Homes scaling plot are normalized by the Drude plasma weight, \(\omega_{p,D}^2\), and show that new universal scaling emerges, in which the superfluid fractions of dirty s-wave and dirty d-wave superconductors coalesce to a single point at which normal-state scattering is occurring at the Planckian bound. The combined result is a new tool for classifying superconductors in terms of order parameter symmetry, as well as scattering strength and character. Although our model starts from a Fermi-liquid assumption it describes underdoped cuprates surprisingly well.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 5 figures
Origin of the tiny energy gap and Dirac points in monoclinic trilayer nickelate La\(_4\)Ni\(_3\)O\(_{10}\)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
Superconductivity was recently found in trilayer nickelate La\(_4\)Ni\(_3\)O\(_{10}\) under high pressure with a phase transition from the monoclinic P2\(_1\)/a structure to the tetragonal I4/mmm structure. Previous experimental works have confirmed the existence of a tiny energy gap formed with Ni 3d\(_{z^2}\) orbitals in monoclinic La\(_4\)Ni\(_3\)O\(_{10}\). Here we investigate the physical origin of this gap by analyzing symmetry properties of energy bands based on the group theory. The tiny gap comes from energy bands with opposite parity at the Brillouin zone center. In addition, we also find previously unknown Dirac points in some momentum directions around the Fermi level. An effective Hamiltonian is constructed to describe low energy physics of the tiny energy gap and Dirac points. Due to the low crystal symmetry of monoclinic La\(_4\)Ni\(_3\)O\(_{10}\), its energy bands display strong anisotropic properties.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
14 pages 5 figures
Enhancement of temperature of quantum anomalous Hall effect in two-dimensional germanene/magnetic semiconductor heterostructures
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Qing-Han Yang, Jia-Wen Li, Xin-Wei Yi, Xiang Li, Jing-Yang You, Gang Su, Bo Gu
Quantum anomalous Hall effect (QAHE) is significant for future low-power electronics devices, where a main challenge is realizing QAHE at high temperatures. In this work, based on experimentally reported two-dimensional (2D) germanene and magnetic semiconductors Cr\(_2\)Ge\(_2\)Te\(_6\) and Cr\(_2\)Si\(_2\)Te\(_6\), and the first principle calculations, germanene/magnetic semiconductor heterostructures are investigated. Topologically nontrivial edge states and quantized anomalous Hall conductance are demonstrated. It is shown that the QAHE temperature can be enhanced to approximately 62 K in germanene/monolayer (ML) Cr\(_2\)Ge\(_2\)Te\(_6\) with 2.1% tensile strain, 64 K in germanene/bilayer (BL) Cr\(_2\)Ge\(_2\)Te\(_6\) with 1.4% tensile strain, and 50 K in germanene/ML Cr\(_2\)Si\(_2\)Te\(_6\) with 1.3% tensile strain. With increasing tensile strain of these heterostructures, the band gap decreases and the Curie temperature rises, and the highest temperature of QAHE is obtained. Since these 2D materials were discovered in recent experiments, our results provide promising materials for achieving high-temperature QAHE.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Theoretical description of atomtronic Josephson junctions in an optical lattice
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-20 20:00 EST
Manjari Gupta, H. R. Krishnamurthy, J. K. Freericks
Experimental realizations of ``atomtronic" Josephson junctions have recently been created in annular traps in relative rotation with respect to potential barriers that generate the weak links. If these devices are additionally subjected to an optical lattice potential, then they can incorporate strong-coupling Mott physics within the design, which can modify the behavior and can allow for interesting new configurations of barriers and of superfluid flow patterns. We examine theoretically the behavior of a Bose superfluid in an optical lattice in the presence of an annular trap and a barrier across the annular region which acts as a Josephson junction. As the superfluid is rotated, circulating super-currents appear. Beyond a threshold superfluid velocity, phase slips develop, which generate vortices. We use a finite temperature strong-coupling expansion about the mean-field solution of the Bose Hubbard model to calculate various properties of such devices. In addition, we discuss some of the rich behavior that can result when there are Mott regions within the system.
Quantum Gases (cond-mat.quant-gas)
12 pages, 9 figures
Asymptotic Freedom of Two Heavy Impurities in a Bose-Einstein Condensate
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-20 20:00 EST
Dong-Chen Zheng, Lin Wen, Renyuan Liao
We consider two heavy impurities immersed in a Bose-Einstein condensate (BEC), and calculate the self-energy using the Wilsonian renormalization. The polaron energy, quasiparticle residue and damping rate are extracted from the self-energy. We demonstrate that various effective potentials emerge from the polaron energy under corresponding conditions. In the limit of large separation between the impurities, the polaron spectrum converges to the results for a single impurity, exhibiting an attractive-repulsive crossover across the Feshbach resonance. The boundary of this crossover is identified through the analysis of the damping rate. We highlight that our analysis reveals a repulsive-dominant polaron exists as long as the impurities are sufficiently close, even when the impurity-boson interactions are attractive. Additionally, we observe that the two impurities become asymptotically free in the repulsive polaron regime. These results are verifiable and offer a fresh perspective on the interaction dynamics between two polarons.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
7 pages, 5 figures
Tunable superconducting diode effect in higher-harmonic InSb nanosheet interferometers
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
Xingjun Wu, Ji-Yin Wang, Haitian Su, Shili Yan, Dong Pan, Jianhua Zhao, Po Zhang, H. Q. Xu
Superconducting diodes, characterized by the nonreciprocal supercurrent flow, have gained significant attention for their potential in dissipationless electronics. This study presents a superconducting quantum interference device (SQUID) composed of two Al-InSb nanosheet Josephson junctions. Utilizing prepatterned local backgates, we achieve a gate- and flux-tunable superconducting diode with controllable efficiency in both amplitude and sign. Numerical simulations attribute the diode effect to higher harmonics in the current-phase relation. Crucially, fractional Shapiro step experiments provide direct insights into the evolution of these higher harmonics with flux tuning, showcasing significant enhancements in the second-harmonic signatures of the SQUID near half-integer flux quanta. Furthermore, we investigate the microwave-assisted diode response and experimentally show that the polarity of the diode effect can be switched by the microwave power. These results demonstrate the potential of InSb nanosheet-based hybrid devices as highly tunable elements for use in dissipationless electronics.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Anomalous Chern-Simons orbital magnetoelectric coupling of three-dimensional Chern insulators: gauge-discontinuity formalism and adiabatic pumping
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Chern-Simons orbital magnetoelectric (OME) coupling is usually the hallmark of nontrivial band topology in three-dimensional (3D) crystalline insulators. However, if a 3D insulator exhibits nonzero Chern number within any two-dimensional plane of the Brillouin zone, then traditionally the Chern-Simons coupling becomes ill defined for such 3D Chern insulators due to topological obstructions. In this work, by employing a ``gauge-discontinuity" formalism, we resolve this long-standing issue and rigorously derive a quantized layer-resolved OME response in 3D Chern insulators. We demonstrate that the difference of the layer-resolved OME coupling between adjacent layers is universally quantized in unit of \(-C e^2/h\), where \(C\) is the Chern number. This quantization arises from an anomalous contribution to the Chern-Simons OME coupling, which is closely associated with the Berry curvature of the occupied bands and the hybrid Wannier centers along the direction of the Chern vector \((0,0, C)\). Furthermore, we demonstrate that the anomalous Chern-Simons coupling can be transported by an exact integer quantum from one unit cell to its neighboring cell through an adiabatic cyclic pumping process, accompanied by a quantized displacement of Wannier center along the direction of the Chern vector. Our work provides a rigorous theoretical framework for understanding magnetoelectric response in 3D Chern insulators and opens avenues for designing topological quantum phenomena in layered systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Accurate Simulation of the Hubbard Model with Finite Fermionic Projected Entangled Pair States
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
Wen-Yuan Liu, Huanchen Zhai, Ruojing Peng, Zheng-Cheng Gu, Garnet Kin-Lic Chan
We demonstrate the use of finite-size fermionic projected entangled pair states, in conjunction with variational Monte Carlo, to perform accurate simulations of the ground-state of the 2D Hubbard model. Using bond dimensions of up to \(D=28\), we show that we can surpass state-of-the-art DMRG energies that use up to \(m=32000\) SU(2) multiplets on 8-leg ladders. We further apply our methodology to \(10\times 16\), \(12\times 16\) and \(16 \times 16\) lattices at \(1/8\) hole doping and observe the dimensional crossover between stripe orientations. Our work shows the power of finite-size fermionic tensor networks to resolve the physics of the 2D Hubbard model and related problems.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con), Quantum Physics (quant-ph)
main text: 5pages, 5 figures
Bright hybrid excitons in molecularly tunable bilayer crystals
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Tomojit Chowdhury, Aurélie Champagne, Patrick Knüppel, Zehra Naqvi, Ariana Ray, Mengyu Gao, David A. Muller, Nathan Guisinger, Kin Fai Mak, Jeffrey B. Neaton, Jiwoong Park
Bilayer crystals, built by stacking crystalline monolayers, generate interlayer potentials that govern excitonic phenomena but are constrained by fixed covalent lattices and orientations. Replacing one layer with an atomically thin molecular crystal overcomes this limitation, as diverse functional groups enable tunable molecular lattices and interlayer potentials, tailoring a wide range of excitonic properties. Here, we report hybrid excitons in four-atom-thick hybrid bilayer crystals (HBCs), directly synthesized with single-crystalline perylene diimide (PDI) molecular crystal atop WS2 monolayers. These excitons arise from a hybridized bilayer band structure, revealed by lattice-scale first-principles calculations, inheriting properties from both monolayers. They exhibit bright photoluminescence with near-unity polarization above and below the WS2 bandgap, along with spectral signatures of exciton delocalization, supported by theory, while their energies and intensities are tuned by modifying the HBC composition by synthesis. Our work introduces a molecule-based 2D quantum materials platform for bottom-up design and control of optoelectronic properties.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
arXiv admin note: text overlap with arXiv:2412.12027
Desmearing two-dimensional small-angle neutron scattering data by central moment expansions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-20 20:00 EST
Guan-Rong Huang, Chi-Huan Tung, Weijian Hua, Yifei Jin, Lionel Porcar, Yuya Shinohara, Christoph U. Wildgruber, Changwoo Doc, Wei-Ren Chen
Resolution smearing is a critical challenge in the quantitative analysis of two-dimensional small-angle neutron scattering (SANS) data, particularly in studies of soft matter flow and deformation using SANS. We present the central moment expansion technique to address smearing in anisotropic scattering spectra, offering a model-free desmearing methodology. By accounting for directional variations in resolution smearing and enhancing computational efficiency, this approach reconstructs desmeared intensity distributions from smeared experimental data. Computational benchmarks using interacting hard-sphere fluids and Gaussian chain models validate the accuracy of the method, while simulated noise analyses confirm its robustness under experimental conditions. Furthermore, experimental validation using the rheo-SANS data of shear-induced micellar structures demonstrates the practicality and effectiveness of the proposed algorithm. The desmearing technique provides a powerful tool for advancing the quantitative analysis of anisotropic scattering patterns, enabling precise insights into the interplay between material microstructure and macroscopic flow behavior.
Soft Condensed Matter (cond-mat.soft)
Ferromagnetic resonance and spin Hall magnetoresistance of Tm3Fe5O12 films
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Yufeng Wang, Peng Zhou, Shuai Liu, Yajun Qi, Tianjin Zhang
Ferromagnetic insulating garnet films with perpendicular magnetic anisotropy (PMA) are of great importance for the applications in spintronics. Tm3Fe5O12 (TmIG) with magnetoelastic anisotropy has been proven to exhibit PMA more easily than Y3Fe5O12. Here, magnetic parameters of TmIG films with various thicknesses are investigated by ferromagnetic resonance. The relationship between effective magnetic magnetization, surface perpendicular anisotropy field, magnetic anisotropy constants and film thickness is established. The parameters of spin Hall angle, spin diffusion length, and real part of the spin mixing conductance are obtained from the measurements of angular dependent magnetoresistance of TmIG/Pt heterostructures.
Materials Science (cond-mat.mtrl-sci)
Emergent extended states in an unbounded quasiperiodic lattice
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-02-20 20:00 EST
Jia-Ming Zhang, Shan-Zhong Li, Shi-Liang Zhu, Zhi Li
Previous studies have established that quasiperiodic lattice models with unbounded potentials can exhibit localized and multifractal states, yet preclude the existence of extended states. In this work, we introduce a quasiperiodic system that incorporates both unbounded potentials and unbounded hopping amplitudes, where extended states emerge as a direct consequence of the unbounded hopping terms overcoming the localization constraints imposed by the unbounded potential, thereby facilitating enhanced particle transport. By using Avila's global theory, we derive analytical expressions for the phase boundaries, with exact results aligning closely with numerical this http URL, we uncover a hidden self-duality in the proposed model by establishing a mapping to the Aubry-André model, revealing a profound structural connection between these systems.
Disordered Systems and Neural Networks (cond-mat.dis-nn)
7 pages, 3 figures
Diffusion Transients in Motility-Induced Phase Separation
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-20 20:00 EST
Shubhadip Nayak, Poulami Bag, Pulak K. Ghosh, Yuxin Zhou, Qingqing Yin, Fabio Marchesoni, Franco Nori
We numerically investigate normal diffusion in a two-dimensional athermal suspension of active particles undergoing motility-induced phase separation. The particles are modeled as achiral Janus disks with fixed self-propulsion speed and weakly fluctuating orientation. When plotted versus the overall suspension packing fraction, the relevant diffusion constant traces a hysteresis loop with sharp jumps in correspondence with the binodal and spinodal of the gaseous phase. No hysteresis loop is observed between the spinodal and binodal of the dense phase, as they appear to overlap. Moreover, even under steady-state phase separation, the particle displacement distributions exhibit non-Gaussian normal diffusion with transient fat (thin) tails in the presence (absence) of phase separation.
Soft Condensed Matter (cond-mat.soft), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Other Condensed Matter (cond-mat.other), Statistical Mechanics (cond-mat.stat-mech), Chemical Physics (physics.chem-ph)
6 figures and 10 pages
Phys. Rev. Research 7, 013153 (2025)
Self-ion irradiation effects on nanoindentation-induced plasticity of crystalline iron: A joint experimental and computational study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
K. Mulewska, F. Rovaris, F. J. Dominguez-Gutierrez, W. Y. Huo, D. Kalita, I. Jozwik, S. Papanikolaou, M. J. Alava, L. Kurpaska, J. Jagielski
In this paper, experimental work is supported by multi-scale numerical modeling to investigate nanomechanical response of pristine and ion irradiated with Fe2+ ions with energy 5 MeV high purity iron specimens by nanoindentation and Electron Backscatter Diffraction. The appearance of a sudden displacement burst that is observed during the loading process in the load-displacement curves is connected with increased shear stress in a small subsurface volume due to dislocation slip activation and mobilization of pre-existing dislocations by irradiation. The molecular dynamics (MD) and 3D-discrete dislocation dynamics (3D-DDD) simulations are applied to model geometrically necessary dislocations (GNDs) nucleation mechanisms at early stages of nanoindentation test; providing an insight to the mechanical response of the material and its plastic instability and are in a qualitative agreement with GNDs density mapping images. Finally, we noted that dislocations and defects nucleated are responsible the material hardness increase, as observed in recorded load-displacement curves and pop-ins analysis.
Materials Science (cond-mat.mtrl-sci)
Giant Uncompensated Magnon Spin Currents in X-type Magnets
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Zi-An Wang, Bo Li, Shui-Sen Zhang, Wen-Jian Lu, Mingliang Tian, Yu-Ping Sun, Evgeny Y. Tsymbal, Kaiyou Wang, Haifeng Du, Ding-Fu Shao
Magnon spin currents in insulating magnets are useful for low-power spintronics. However, in magnets stacked by antiferromagnetic (AFM) exchange coupling, which have recently aroused significant interest for potential applications in spintronics, these currents are largely counteracted by opposite magnetic sublattices, thus suppressing their net effect. Contrary to this common observation, here, we show that magnets with X-type AFM stacking, where opposite magnetic sublattices form orthogonal intersecting chains, support giant magnon spin currents with minimal compensation. Our model Hamiltonian calculations predict magnetic chain locking of magnon spin currents in these X-type magnets, significantly reducing their compensation ratio. In addition, the one-dimensional nature of the chain-like magnetic sublattices enhances magnon spin conductivities surpassing those of two-dimensional ferromagnets and canonical altermagnets. Notably, uncompensated X-type magnets, such as odd-layer antiferromagnets and ferrimagnets, can exhibit magnon spin currents polarized opposite to those expected by their net magnetization. These unprecedented properties of X-type magnets, combined with their inherent advantages resulting from AFM coupling, offer a promising new path for low-power high-performance spintronics.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Unravelling the influence of shell thickness in organic functionalized Cu2O nanoparticles on C2+ products distribution in electrocatalytic CO2 reduction
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Jiajun Hu, Silvio Osella, Josep Albero, Hermenegildo García
Cu-based electrocatalysts exhibits enormous potential for electrochemical CO2 conversion to added-value products. However, high selectivity, specially towards C2+ products, remains a critical challenge for its implementation in commercial applications. Herein, we report the preparation of a series of electrocatalysts based on octadecyl amine (ODA) coated Cu2O nanoparticles. HRTEM images show ODA coatings with thickness from 1.2 to 4 nm. DFT calculations predict that at low surface coverage, ODA tends to lay on the Cu2O surface, leaving hydrophilic regions. Oppositely, at high surface coverage, the ODA molecules are densely packed, being detrimental for both mass and charge transfer. These changes in ODA molecular arrangement explain differences in product selectivity. In situ Raman spectroscopy has revealed that the optimum ODA thickness contributes to the stabilization of key intermediates in the formation of C2+ products, especially ethanol. Electrochemical impedance spectroscopy and pulse voltammetry measurements confirm that the thicker ODA shells increase charge transfer resistance, while the lowest ODA content promotes faster intermediate desorption rates. At the optimum thickness, the intermediates desorption rates are the slowest, in agreement with the maximum concentration of intermediates observed by in situ Raman spectroscopy, thereby resulting in a Faradaic efficiency to ethanol and ethylene over 73 %.
Materials Science (cond-mat.mtrl-sci)
Adv. Funct. Mater. 2024, 34, 2404566
Mixed Fe-Mo carbide prepared by a sonochemical synthesis as highly efficient nitrate reduction electrocatalyst
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Jiajun Hu, Silvio Osella, Eduardo Arizono dos Reis, Anelisse Brunca da Silva, Caue Ribeiro, Lucia Helena Mascaro, Josep Albero, Hermenegildo Garcia
Ammonia, a versatile compound that can be used as a fertilizer, chemical or fuel, has since long been produced through the energy-intensive Haber-Bosch process. Recently, the electrochemical nitrate reduction reaction (NO3RR) using electricity generated from renewable sources has attracted widespread attention. However, the complex reaction pathway of NO3RR leads to the formation of many undesirable by-products. Herein we successfully prepared a mixed (FeMo)2C catalyst with good electrocatalytic NO3RR, having a NH3 yield of 14.66 mg h-1 cm-2 and an FE of 94.35 % at low potential -0.3 V vs RHE. DFT calculations show that the presence of Fe in Mo2C lattice changes the reaction mechanism, decreasing the potential barrier to be overcome from 1.36 to 0.89 eV. In addition, mixed Fe-Mo carbide facilitates the adsorption of intermediates and promotes NH3 desorption, facilitating NO3- reduction to NH3. In addition, (FeMo)2C was used as cathode for Zn-NO3 battery to generate electricity, producing ammonia at the same time, with a power density of 3.8 mWcm-2 and an NH3 FE of 88 %. This work describes a new synthesis method for mixed metal carbides and provides a promising strategy for NH3 production.
Materials Science (cond-mat.mtrl-sci)
Appl. Catal. B-Environ 2024, 357, 124247
Two-dimensional higher-order Weyl semimetals
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Lizhou Liu, Qing-Feng Sun, Ying-Tao Zhang
We propose a theoretical scheme to realize two-dimensional higher-order Weyl semimetals using a trilayer topological insulator film coupled with a d-wave altermagnet. Our results show that the trilayer topological insulator exhibits two-dimensional Weyl semimetal characteristics with helical edge states. Notably, the Weyl points are located at four high-symmetry points in the Brillouin zone, and the topology of symmetric subspaces governs the formation of these Weyl points and edge states. Upon introducing a d-wave altermagnet oriented along the z-direction, gaps open in the helical edge states while preserving two Weyl points, leading to the realization of two-dimensional higher-order Weyl semimetals hosting topological corner states. The nonzero winding number in the subspace along the high-symmetry line serves as a topological invariant characterizing these corner states, and the other subspace Hamiltonian confirms the existence of the Weyl points. Finally, a topological phase diagram provides a complete topological description of the system.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 4 figures
Photogalvanic Shift Currents in BiFeO3 --LaFeO3 Superlattices
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Francesco Delodovici (SPMS), Charles Paillard
Designing materials with controlled photovoltaic response may lead to improved solar cells or photosensors. In this regard, ferroelectric superlattices have emerged as a rich platform to engineer functional properties. In addition, ferroelectrics are naturally endowed with a bulk photovoltaic response stemming from non-thermalized photoexcited carriers, which can overcome the fundamental limits of current solar cells. Yet, their photovoltaic output has been limited by poor optical absorption and poor charge collection or photo-excited carrier mean free path. We use Density Functional Theory and Wannierization to compute the so-called Bulk Photovoltaic shift current and the optical properties of BiFeO3/LaFeO3 superlattices. We show that, by stacking these two materials, not only the optical absorption is improved at larger wavelengths (due to LaFeO3 smaller bandgap), but the photovolgavanic shift current is also enhanced compared to that of pure BiFeO3 , by suppressing the destructive interferences occurring between different wavelengths.
Materials Science (cond-mat.mtrl-sci)
ACS Applied Energy Materials, 2025, 8 (3), pp.1716-1721
Quantum spin Hall effect in bilayer honeycomb lattices with C-type antiferromagnetic order
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Lizhou Liu, Cheng-Ming Miao, Qing-Feng Sun, Ying-Tao Zhang
We propose a scheme to realize time-reversal symmetry-broken quantum spin Hall insulators using bilayer honeycomb lattices, combining intrinsic spin-orbit coupling, C-type antiferromagnetic ordering, and staggered potentials. The C-type antiferromagnetic order emerges from the interplay between intralayer antiferromagnetism and interlayer ferromagnetism. The system's topological properties are characterized by the spin Chern number. We present the topological phase diagram of the bilayer honeycomb lattice, providing a detailed insight into the stability and tunability of the quantum spin Hall effect in this system. The presence of helical edge states is confirmed by the measurement of quantized longitudinal resistance values of 3/2(h/e2) and 1/2(h/e2) in a sixterminal Hall-bar device. Remarkably, this quantum spin Hall insulator phase is protected by interlayer parity-time (PT) symmetry, despite the breaking of time-reversal symmetry.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 pages, 5 figures
Anatomy of Spin Wave Polarization in Ferromagnets
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Yutian Wang, Ruoban Ma, Jiang Xiao
Spin waves in ferromagnetic materials are predominantly characterized by right-handed circular polarization due to symmetry breaking induced by net magnetization. However, magnetic interactions, including the external magnetic field, Heisenberg exchange, Dzyaloshinskii-Moriya interaction, and dipole-dipole interaction, can modify this behavior, leading to elliptical polarization. This study provides a systematic analysis of these interactions and their influence on spin wave polarization, establishing principles to predict traits such as polarization degree and orientation based on equilibrium magnetization textures. The framework is applied to diverse magnetic configurations, including spin spirals, domain walls, and Skyrmions, offering a comprehensive yet simple approach to understanding polarization dynamics in ferromagnetic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
8 pages, 3 figures
Controlling deposition and characterising dynamics of thin liquid films with high temporal and spatial resolution
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-20 20:00 EST
G Le Lay (Upcité, Inp-Cnrs, Insis - Cnrs), A Daerr (Upcité, Inp-Cnrs, Insis - Cnrs)
The high inertia of classical fluid coating processes severely limits the possibility of controlling the deposited film thickness through the entrainment velocity. We describe and characterize a new experimental device where the inertia is dramatically reduced, allowing for millimeter-scale patterning with micrometer-accurate thickness. Measuring precise film profiles over large spatial extents with high temporal resolution poses a challenge, which we overcome using a custom interferometric set-up coupled with state-of-the-art signal processing. The sensitivity of our method allows us to resolve film thinning rates in the nanometer-per-second range, and to quantify the relative contribution of surface-tension and gravity driven flows. We apply this method by showing that the thickness of the deposited film obeys the classical Landau-Levich scaling even when the meniscus faces important acceleration.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
Finite-rate quench in disordered Chern and \(Z_2\) topological insulators
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
We study quantum quench of finite rate across topological quantum transitions in two-dimensional Chern and \(Z_2\) topological insulators. We choose the representative Haldane model and the Kane-Mele model to investigate the behavior of excitation density generated by the quench and the impact of disorder. For the Haldane model, as long as the spectral gap is not closed by disorder, we find the excitation density at the end of the quench obeys the power-law scaling with the quench rate, consistent with the prediction of the Kibble-Zurek mechanism. However, anti-Kibble-Zurek behavior is observed in disordered Kane-Mele model, which we attribute to the existence of a disorder-induced gapless region. Moreover, we demonstrate that particle's onsite occupation can be used as a local measurable quantity to probe the breakdown of adiabatic evolution, which exhibits similar dependence on the quench rate as the excitation density for both the Haldane and Kane-Mele models. This similarity still holds in the bulk of the system even when we consider realistic open boundary conditions, facilitating the experimental characterization of the dynamic features in these models.
Strongly Correlated Electrons (cond-mat.str-el)
12 pages, 9 figures
DFT+DMFT study on pressure-induced valence instability of CeCoSi
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
Shuai-Kang Zhang, Yuanji Xu, Guojun Li, Junshuai Wang, Zhongpo Zhou, Yipeng An
Rare-earth compounds RCoSi exhibit unique properties, with distinct structural behaviors depending on whether R is a light, middle or heavy rare-earth element. Among them, CeCoSi undergoes a structural phase transition under high pressure, with the phase transition pressure increasing as temperature rises. Some experimental studies suggest that the transition is closely related to the behavior of Ce-4f electrons. In this work, we systematically studied the evolution of the electronic structure of CeCoSi with temperature and pressure. First, we used the DFT+DMFT to calculate the energy-volume curve of CeCoSi, which was in good agreement with the experimental results and far superior to the DFT method. Next, we studied the electronic structure of CeCoSi under different pressures and temperatures using DFT+DMFT. Our results show that CeCoSi is a Kondo metal with hybridization of Ce-4f and Co-3d. As pressure increases, the renormalization factor Z of Ce-4f5/2 increases, the occupancy number of Ce-4f electrons decreases, and CeCoSi transitions to a mixed-valence state at ~5.5 GPa in 100 K. The pressure of the quantum phase transition PQ is slightly higher than the experimentally observed structural phase transition pressure PS, and the PQ increases with increasing temperature, which is consistent with the behavior of PS in experiment. In addition, the hybridization strength of Ce-4f in the mixed-valence state is significantly greater than in the Kondo metal state. Our results suggest that the valence instability of Ce-4f is the cause of the structural phase transition. As pressure increases, Ce-4f electrons delocalize and CeCoSi transitions to mixed-valence state. This valence instability may cause redistribution of electron density, thus inducing a structural phase transition. Our work reveals the cause of the structural phase transition of CeCoSi under high pressure.
Strongly Correlated Electrons (cond-mat.str-el)
15 pages, 6 figures
Tunneling magnetoresistance in altermagnetic RuO\(_2\)-based magnetic tunnel junctions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Seunghyeon Noh, Gye-Hyeon Kim, Jiyeon Lee, Hyeonjung Jung, Uihyeon Seo, Gimok So, Jaebyeong Lee, Seunghyun Lee, Miju Park, Seungmin Yang, Yoon Seok Oh, Hosub Jin, Changhee Sohn, Jung-Woo Yoo
Altermagnets exhibit characteristics akin to antiferromagnets, with spin-split anisotropic bands in momentum space. RuO\(_2\) has been considered as a prototype altermagnet; however, recent reports have questioned altermagnetic ground state in this material. In this study, we provide direct experimental evidence of altermagnetic characteristics in RuO\(_2\) films by demonstrating spin-dependent tunneling magnetoresistance (TMR) in RuO\(_2\)-based magnetic tunnel junctions. Our results show the spin-splitted anisotropic band structure of RuO\(_2\), with the observed TMR determined by the direction of the Néel vector of RuO\(_2\). These results reflect the altermagnetic nature of RuO\(_2\) and highlight its potential for spintronic applications, leveraging the combined strengths of ferromagnetic and antiferromagnetic systems.
Materials Science (cond-mat.mtrl-sci)
AV\(_3\)Sb\(_5\) kagome superconductors: a review with transport measurements
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
Kagome systems have garnered considerable attention due to the unique features of the sublattice structure and band topology. The recently discovered kagome metals AV\(_3\)Sb\(_5\) (where A = K, Rb, Cs) host a rich array of symmetry-breaking phases, including exotic charge density waves (CDW), electronic nematicity, pair density waves (PDW) and superconductivity. Despite extensive experimental and theoretical investigations into the diverse phases, several key issues remain contentious, such as a solid clarification of the time-reversal symmetry breaking (TRS-breaking) in the CDW order and its implications for the nature of superconducting (SC) pairing symmetry. This review aims to shed light on the transport properties of these intertwined phases, emphasizing the pivotal role that transport measurements play in uncovering the non-trivial quantum states of matter.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Visualizing Nanodomain Superlattices in Halide Perovskites Giving Picosecond Quantum Transients
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Dengyang Guo, Thomas A. Selby, Simon Kahmann, Sebastian Gorgon, Linjie Dai, Milos Dubajic, Terry Chien-Jen Yang, Simon M. Fairclough, Thomas Marsh, Ian E. Jacobs, Baohu Wu, Renjun Guo, Satyawan Nagane, Tiarnan A. S. Doherty, Kangyu Ji, Cheng Liu, Yang Lu, Taeheon Kang, Capucine Mamak, Jian Mao, Peter Müller-Buschbaum, Henning Sirringhaus, Paul A. Midgley, Samuel D. Stranks
The high optoelectronic quality of halide perovskites lends them to be utilized in optoelectronic devices and recently in emerging quantum emission applications. Advancements in perovskite nanomaterials have led to the discovery of processes in which luminescence decay times are sub-100 picoseconds, stimulating the exploration of even faster radiative rates for advanced quantum applications, which have only been prominently realised in III-V materials grown through costly epitaxial growth methods. Here, we discovered ultrafast quantum transients of time scales ~2 picoseconds at low temperature in bulk formamidinium lead iodide films grown through scalable solution or vapour approaches. Using a multimodal strategy, combining ultrafast spectroscopy, optical and electron microscopy, we show that these transients originate from quantum tunnelling in nanodomain superlattices. The outcome of the transient decays, photoluminescence, mirrors the photoabsorption of the states, with an ultra-narrow linewidth at low temperature as low as <2 nm (~4 meV). Localized correlation of the emission and structure reveals that the nanodomain superlattices are formed by alternating ordered layers of corner sharing and face sharing octahedra. This discovery opens new applications leveraging intrinsic quantum properties and demonstrates powerful multimodal approaches for quantum investigations.
Materials Science (cond-mat.mtrl-sci)
Main text and supplementary information. Main text 18 pages, 4 figures. Supplementary information 47 pages, 34 figures
Evidence for spin-fluctuation-mediated superconductivity in electron-doped cuprates
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
C. M. Duffy, S. J. Tu, Q. H. Chen, J. S. Zhang, A. Cuoghi, R. D. H. Hinlopen, T. Sarkar, R. L. Greene, K. Jin, N. E. Hussey
In conventional, phonon-mediated superconductors, the transition temperature \(T_c\) and normal-state scattering rate \(1/\tau\) - deduced from the linear-in-temperature resistivity \(\rho(T)\) - are linked through the electron-phonon coupling strength \(\lambda_{\rm ph}\). In cuprate high-\(T_c\) superconductors, no equivalent \(\lambda\) has yet been identified, despite the fact that at high doping, \(\alpha\) - the low-\(T\) \(T\)-linear coefficient of \(\rho(T)\) - also scales with \(T_c\). Here, we use dc resistivity and high-field magnetoresistance to extract \(\tau^{-1}\) in electron-doped La\(_{2-x}\)Ce\(_x\)CuO\(_4\) (LCCO) as a function of \(x\) from optimal doping to beyond the superconducting dome. A highly anisotropic inelastic component to \(\tau^{-1}\) is revealed whose magnitude diminishes markedly across the doping series. Using known Fermi surface parameters and subsequent modelling of the Hall coefficient, we demonstrate that the form of \(\tau^{-1}\) in LCCO is consistent with scattering off commensurate antiferromagnetic spin fluctuations of variable strength \(\lambda_{\rm sf}\). The clear correlation between \(\alpha\), \(\lambda_{\rm sf}\) and \(T_c\) then identifies low-energy spin-fluctuations as the primary pairing glue in electron-doped cuprates. The contrasting magnetotransport behaviour in hole-doped cuprates suggests that the higher \(T_c\) in the latter cannot be attributed solely to an increase in \(\lambda_{\rm sf}\). Indeed, the success in modelling LCCO serves to reinforces the notion that resolving the origin of high-temperature superconductivity in hole-doped cuprates may require more than a simple extension of BCS theory.
Superconductivity (cond-mat.supr-con), Strongly Correlated Electrons (cond-mat.str-el)
Main article (5 figures) plus Methods (10 figures); 28 pages in total
Bound states of quasiparticles with quartic dispersion in an external potential: WKB approach
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
The Wentzel-Kramers-Brillouin semiclassical method is formulated for quasiparticles with quartic-in-momentum dispersion which presents the simplest case of a soft energy-momentum dispersion. It is shown that matching wave functions in the classically forbidden and allowed regions requires the consideration of higher-order Airy-type functions. The asymptotics of these functions are found by using the method of steepest descents and contain additional exponentially suppressed contributions known as hyperasymptotics. These hyperasymptotics are crucially important for the correct matching of wave functions in vicinity of turning points for higher-order differential equations. A quantization condition for bound state energies is obtained, which generalizes the standard Bohr-Sommerfeld condition for particles with quadratic energy-momentum dispersion and contains nonperturbative in \(\hbar\) correction. The quantization condition is used to find bound state energies in the case of quadratic and quartic potentials.
Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
15 pages, 4 figures
Time-delayed Newton's law of cooling with a finite-rate thermal quench. Impact on the Mpemba and Kovacs effects
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-20 20:00 EST
The Mpemba and Kovacs effects are two notable memory phenomena observed in nonequilibrium relaxation processes. In a recent study [Phys.Rev.E , 044149 (2024)], these effects were analyzed within the framework of the time-delayed Newton's law of cooling under the assumption of instantaneous temperature quenches. Here, the analysis is extended to incorporate finite-rate quenches, characterized by a nonzero quench duration \(\sigma\). The results indicate that a genuine Mpemba effect is absent under finite-rate quenches if both samples experience the same thermal environment during the quenching process. However, if \(\sigma\) remains sufficiently small, the deviations in the thermal environment stay within an acceptable range, allowing the Mpemba effect to persist with a slightly enhanced magnitude. In contrast, the Kovacs effect is significantly amplified, with the transient hump in the temperature evolution becoming more pronounced as both the waiting time and \(\sigma\) increase. These findings underscore the importance of incorporating finite-time effects in nonequilibrium thermal relaxation models and offer a more realistic perspective for experimental studies.
Statistical Mechanics (cond-mat.stat-mech), Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft), Classical Physics (physics.class-ph), Fluid Dynamics (physics.flu-dyn)
10 pages, 10 figures
Promising High Temperature Thermoelectric Performance of Alkali Metal-based Zintl phases X\(_2\)AgY (X = Na, K; Y = Sb, Bi): Insights from First-Principles Studies
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Mohd Zeeshan, Indranil Mal, B K Mani
In the quest for novel thermoelectric materials to harvest waste environmental heat, we investigate alkali metal-based Zintl phases X\(_2\)AgY (X = Na, K, and Y = Sb, Bi) utilizing first-principles methods. We obtain significantly low lattice thermal conductivity values ranging 0.9-0.5 W m\(^{-1}\) K\(^{-1}\) at 300~K, challenging established thermoelectric materials such as SnSe, PbTe, Bi\(_2\)Te\(_3\) as well as other Zintl phases. We trace such astonishingly low values to lattice anharmonicity, large phonon scattering phase space, low phonon velocities, and lifetimes. In K-based materials, the low phonon velocities are further linked to flattened phonon modes arising from the gap in the optical spectrum. Furthermore, the existence of bonding heterogeneity could hamper heat conduction in these materials. In addition, an avoided crossing in the phonon dispersions suggesting rattling behavior, observed in all materials except Na\(_2\)AgSb, suppresses the dispersion of acoustic modes, further reducing the phonon velocities. When combined with electrical transport calculations, the materials exhibit high figure of merit values at 700~K, i.e., \(ZT\sim2.1\) for Na\(_2\)AgSb, \(1.7\) for Na\(_2\)AgBi, \(0.9\) for K\(_2\)AgSb, and \(1.0\) for K\(_2\)AgBi. Our predicted \(ZT\) values are competitive with state-of-the-art thermoelectric materials such as Mg\(_3\)Sb\(_2\), ZrCoBi, PbTe, SnSe, and as well as with contemporary Zintl phases. Our findings underscore the potential of light alkali metal atoms combined with Ag-Bi/Sb type frameworks to achieve superior thermoelectric performance, paving the way for material design for specific operating conditions.
Materials Science (cond-mat.mtrl-sci)
13 pages, 9 figures, 1 table
Interfacial superconductivity in the type-III heterostructure SnSe\(_2\)/PtTe\(_2\)
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
Jun Fan, Xiao-Le Qiu, Zhong-Yi Lu, Kai Liu, Ben-Chao Gong
Interfacial superconductivity (IS) has been a topic of intense interest in the condensed matter physics, due to its unique properties and exotic photoelectrical performance. However, there are few reports about IS systems consisting of two insulators. Here, motivated by the emergence of an insulator-metal transition in the type-III heterostructure and the superconductivity in the some "special" two-dimensional (2D) semiconductors via the electron doping, we predict that 2D heterostructure SnSe\(_2\)/PtTe\(_2\) is a model system for realizing the IS by using first-principles calculations. Our results show that due to the slight but crucial interlayer charge transfer, SnSe\(_2\)/PtTe\(_2\) turns to be a type-III heterostructure with metallic properties and shows a superconducting transition with the critical temperature (\(T_\text{c}\)) of 3.73 K. Similar to the enhance electron-phonon coupling (EPC) in the electron doped SnSe\(_2\) monolayer, the IS in the heterostructure SnSe\(_2\)/PtTe\(_2\) mainly originates from the metallized SnSe\(_2\) layer. Furthermore, we find that the superconductivity is sensitive to the tensile lattice strain, forming a dome-shaped superconducting phase diagram. Remarkably, at the 7% tensile strain, the superconducting \(T_\text{c}\) can increase more than twofold (8.80 K), resulting from the softened acoustic phonon at the M point and the enhanced EPC strength. Our study provides a concrete example for realizing IS in the type-III heterosturcture, which waits for future experimental verification.
Superconductivity (cond-mat.supr-con)
Silicon oxide nanoparticles grown on graphite by codeposition of the atomic constituents
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Steffen Friis Holleufer, Alfred Hopkinson, Duncan S. Sutherland, Zheshen Li, Jeppe V. Lauritsen, Liv Hornekær, Andrew Cassidy
Nanoscale silicate dust particles are the most abundant refractory component observed in the interstellar medium and thought to play a key role in catalysing the formation of complex organic molecules in the star forming regions of space. We present a method to synthesise a laboratory analogue of nanoscale silicate dust particles on highly oriented pyrolytic graphite (HOPG) substrates by co-deposition of the atomic constituents. The resulting nanoparticulate films are sufficiently thin and conducting to allow for surface science investigations, and are characterised here, in situ under UHV, using X-ray photoelectron spectroscopy, near-edge X-ray absorption atomic fine spectroscopy and scanning tunnelling microscopy, and, ex situ, using scanning electron microscopy. We compare SiO\(_{x}\) film growth with and without the use of atomic O beams during synthesis and conclude that exposure of the sample to atomic O leads to homogeneous films of interconnected nanoparticle networks. The networks covers the graphite substrate and demonstrate superior thermal stability, up to 1073 K, when compared to oxides produced without exposure to atomic O. In addition, control over the flux of atomic O during growth allows for control of the average oxidation state of the film produced. Photoelectron spectroscopy measurements demonstrate that fully oxidised films have an SiO\(_{2}\) stoichiometry very close to bulk SiO\(_{2}\) and scanning tunnelling microscopy images show the basic cluster building unit to have a radius of approximately 2.5 nm. The synthesis of SiO\(_{x}\) films with adjustable stoichiometry and suitable for surface science experiments that require conducting substrates will be of great interest to the astrochemistry community, and will allow for nanoscale-investigation of the chemical processes thought to be catalysed at the surface of dust grains in space.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Neural Density Functional Theory in Higher Dimensions with Convolutional Layers
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-20 20:00 EST
Felix Glitsch, Jens Weimar, Martin Oettel
Based on recent advancements in using machine learning for classical density functional theory for systems with one-dimensional, planar inhomogeneities, we propose a machine learning model for application in two dimensions (2D) akin to density functionals in weighted density forms, as e. g. in fundamental measure theory (FMT). We implement the model with fast convolutional layers only and apply it to a system of hard disks in fully 2D inhomogeneous situations. The model is trained on a combination of smooth and steplike external potentials in the fluid phase. Pair correlation functions from test particle geometry show very satisfactory agreement with simulations although these types of external potentials have not been included in the training. The method should be fully applicable to 3D problems, where the bottleneck at the moment appears to be in obtaining smooth enough 3D histograms as training data from simulations.
Statistical Mechanics (cond-mat.stat-mech)
Unveiling the Interfacial Reconstruction Mechanism Enabling Stable Growth of the Delafossite PdCoO2 on Al2O3 and LaAlO3
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Anna Scheid, Tobias Heil, Y. Eren Suyolcu, Qi song, Niklas Enderlein, Arnaud P. Nono Tchiomo, Prosper Ngabonzigza, Philipp Hansmann, Darrell G. Schlom, Peter A. van Aken
Delafossites, comprised of noble metal (A+) and strongly correlated sublayers (BO2-), form natural superlattices with highly anisotropic properties. These properties hold significant promise for various applications, but their exploitation hinges on the successful growth of high-quality thin films on suitable substrates. Unfortunately, the unique lattice geometry of delafossites presents a significant challenge to thin-film fabrication. Different delafossites grow differently, even when deposited on the same substrate, ranging from successful epitaxy to complete growth suppression. These variations often lack a clear correlation to obvious causes like lattice mismatch. Unidentified stabilization mechanisms appear to enable growth in certain cases, allowing these materials to form stable thin films or act as buffer layers for subsequent delafossite growth. This study employs advanced scanning transmission electron microscopy techniques to investigate the nucleation mechanism underlying the stable growth of PdCoO2 films on Al2O3 and LaAlO3 substrates, grown via molecular-beam epitaxy. Our findings reveal the presence of a secondary phase within the substrate surface that stabilizes the films. This mechanism deviates from the conventional understanding of strain relief mechanisms at oxide heterostructure interfaces and differs significantly from those observed for Cu-based delafossites.
Materials Science (cond-mat.mtrl-sci)
Impact of friction and grain shape on the morphology of sheared granular media
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-20 20:00 EST
Huzaif Rahim, Sudeshna Roy, Thorsten Pöschel
The interplay between dilatancy and particle alignment in sheared granular materials composed of non-spherical particles leads to morphological inhomogeneity. Dilatancy, driven by interparticle friction, causes the packing to expand, while particle alignment tends to densify it. We examine the influence of friction, particle aspect ratio, and initial packing conditions on the steady-state particle alignment and packing density. Unlike spherical particles, non-spherical particles with higher AR exhibit either dilatancy or compaction under shear, leading to spontaneous heaping or depression formation. We analyzed the evolution of packing density to identify whether dilatancy or compression prevails within the shear band.
Soft Condensed Matter (cond-mat.soft)
Restriction of macroscopic structural superlubricity due to structure relaxation by the example of twisted graphene bilayer
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Alexander S. Minkin, Irina V. Lebedeva, Andrey M. Popov, Sergey A. Vyrko, Nikolai A. Poklonski, Yurii E. Lozovik
The effect of structure relaxation on the potential energy surface (PES) of interlayer interaction of twisted graphene bilayer is studied for a set of commensurate moiré systems using the registry-dependent empirical potential of Kolmogorov and Crespi. It is found that the influence of structure relaxation on the amplitude of PES corrugations (determining static friction) depends on the unit cell size (or related twist angle) of the moiré system. For moiré systems with the smallest unit cells, the amplitudes of PES corrugations calculated with and without account of structure relaxation are approximately the same. However, for large unit cell sizes, the structure relaxation can lead to an increase of PES corrugations by orders of magnitude. This means that structure relaxation can provide the main contribution into the static friction of a superlubric system under certain conditions (such as the contact size and twist angle). Moreover, the change of the PES type because of structure relaxation from a trigonal lattice of maxima to a trigonal lattice of minima is observed for the systems with the moiré patterns (5,1) and (5,3). Based on the results obtained, possible crossovers between static friction modes taking place upon changing the twist angle in a macroscopic superlubric system consisting of identical layers are discussed. Additionally it is shown that the PES for relaxed structures can still be approximated by the first Fourier harmonics compatible with symmetries of twisted layers analogously to the PES for rigid layers.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
11 pages, 4 figures
Phys. Rev. Materials 9, 024002 (2025)
On determining the energy dispersion of spin excitations with scanning tunneling spectroscopy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
J. C. G. Henriques, Chenxiao Zhao, G. Catarina, Pascal Ruffieux, Roman Fasel, J. Fernández-Rossier
Conventional methods to measure the dispersion relations of collective spin excitations involve probing bulk samples with particles such as neutrons, photons or electrons, which carry a well-defined momentum. Open-ended finite-size spin chains, on the contrary, do not have a well-defined momentum due to the lack of translation symmetry, and their spin excitations are measured with an eminently local probe, using inelastic electron tunneling spectroscopy (IETS) with a scanning tunneling microscope (STM). Here we discuss under what conditions STM-IETS spectra can be Fourier-transformed to yield dispersion relations in these systems. We relate the success of this approach to the degree to which spin excitations form standing waves. We show that STM-IETS can reveal the energy dispersion of magnons in ferromagnets and triplons in valence bond crystals, but not that of spinons, the spin excitations in Heisenberg spin-1/2 chains. We compare our theoretical predictions with state-of-the-art measurements on nanographene chains that realize the relevant spin Hamiltonians.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
6 pages, 4 figures
The link between Microstructural Heterogeneity, Diffusivity, and Hydrogen Embrittlement
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Daniel J Long, Edmund Tarleton, Alan CF Cocks, Felix Hofmann
Green hydrogen is likely to play a major role in decarbonising the aviation industry. It is crucial to understand the effects of microstructure on hydrogen redistribution, which may be implicated in the embrittlement of candidate fuel system metals. We have developed a stochastic multiscale finite element modelling framework that integrates micromechanical and hydrogen transport models, such that the dominant microstructural effects can be efficiently accounted for at millimetre length scales. Our results show that microstructure has a significant effect on hydrogen localisation in elastically anisotropic materials, which exhibit an interesting interplay between microstructure and millimetre-scale hydrogen redistribution at various loading rates. Considering 316L stainless steel and nickel, a direct comparison of model predictions against experimental hydrogen embrittlement data reveals that the reported sensitivity to loading rate is strongly linked with rate-dependent grain scale diffusion. These findings highlight the need to incorporate microstructural characteristics in the design of hydrogen resistant materials.
Materials Science (cond-mat.mtrl-sci)
Transmission Probability in Double Quantum Well with Triple Barrier
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Krishna Rana Magar, Upendra Rijal, Sanju Shrestha
Quantum well of AlGaAs/GaAs is very important to study transport properties of electrons due to its wider application in electronic devices. Hence, the double well of AlGaAs/GaAs with triple barrier is taken to study transmission probability. Transmission probability is found to decrease with the increase in the height and width of the barrier. Transmission probability with energy of electron shows two peaks while taking all three barrier of the same height. Whereas a single and higher value of peak is found when the height of the central barrier is slightly reduced.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Interplay of carrier density and mobility in Al-Rich (Al,Ga)N-Channel HEMTs: Impact on high-power device performance potential
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Badal Mondal, Pietro Pampili, Jayjit Mukherjee, David Moran, Peter James Parbrook, Stefan Schulz
Despite considerable advancements, high electron mobility transistors (HEMTs) based on gallium nitride (GaN) channels remain largely limited to power applications below 650 V. For higher power demands, the ultra-wide bandgap semiconductor alloy aluminium gallium nitride, (Al,Ga)N, has emerged as a key contender for next-generation HEMTs. In this theoretical study, we show that Al-rich Al\(_x\)Ga\(_{1-x}\)N-channel HEMTs (with \(x \geq 0.5\)) outperform the GaN-channel counterparts at and above room temperature, across all Al compositions, \(x\). This contrasts with recent theory reports which suggest that only Al\(_x\)Ga\(_{1-x}\)N HEMTs with high Al content (\(x \geq 0.85\)) offer comparable performance to GaN-channel devices. Unlike previous assumptions of a constant two-dimensional electron gas (2DEG) density across the entire composition range \(x\), we show that the 2DEG density is highly sensitive to both the Al content and thickness of the individual layers in a HEMT structure. We demonstrate that the superior performance of Al-rich (Al,Ga)N-channel HEMTs is driven by a competing effect between 2DEG density and electron mobility. This work challenges the assumptions of prior studies, which can result in a significant under or overestimation of the potential of high Al content HEMTs. The insights gained from our work provide a comprehensive understanding of the trade-offs between device and material parameters, thus help to guide the design of future Al-rich (\(x = 0.5-1.0\)) Al\(_x\)Ga\(_{1-x}\)N-channel HEMTs for high-power applications.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Main article: 7 pages, 5 figures; Supplementary article: 16 pages, 12 figures, 10 sections; Supplementary attachment: (Processed) Data and additional supplementary figures
Inherited Berry curvature of phonons in Dirac materials with time-reversal symmetry
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Sayandip Ghosh, Selçuk Parlak, Ion Garate
The Berry curvature of phonons is an active subject of research in condensed matter physics. Here, we present a model in which phonons acquire a Berry curvature through their coupling to electrons in crystals with time-reversal symmetry. We illustrate this effect for BaMnSb\(_2\), a quasi two-dimensional Dirac insulator, whose low-energy massive Dirac fermions generate a phonon Berry curvature that is proportional to the electronic valley Chern number.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
13 pages (including appendices), 2 figures
Quantum Coherent Transport of 1D ballistic states in second order topological insulator Bi\(_4\)Br\(_4\)
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
J. Lefeuvre, M. Kobayashi, G. Patriarche, N. Findling, D. Troadec, M. Ferrier, S. Guéron, H. Bouchiat, T. Sasagawa, R. Deblock
We investigate quantum transport in micrometer-sized single crystals of Bi\(_4\)Br\(_4\), a material predicted to be a second-order topological insulator. 1D topological states with long phase coherence times are revealed via the modulation of quantum interferences with magnetic field and gate voltage. In particular, we demonstrate the existence of Aharanov-Bohm interference between 1D ballistic states several micrometers long, that we identify as phase-coherent hinge modes on neighbouring step edges at the crystal surface. These Aharanov-Bohm interferences are made possible by a disordered phase-coherent contact region, the existence of which is confirmed by STEM/EDX imaging of FIB lamellae. Their coherent nature modulates the transmission of the 1D edge states, leading to weak antilocalization and universal conductance fluctuations with surprisingly large characteristic fields and a strongly anisotropic behavior. These complementary experimental results provide a comprehensive, coherent description of quantum transport in Bi\(_4\)Br\(_4\), and establishes the material as belonging to the class of second-order topological insulators with topologically protected 1D ballistic states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Main text and Supplemental material
Interfacial superconductivity and a Se-vacancy ordered insulating phase in the FeSe/PbOx heterostructures
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-20 20:00 EST
Yunkai Guo, Xuanyu Long, Jingming Yan, Zheng Liu, Qi-Kun Xue, Wei Li
The discovery of high-temperature superconductivity in FeSe/SrTiO3 has sparked significant interests in exploring new superconducting systems with engineered interfaces. Here, using molecular beam epitaxy growth, we successfully fabricate FeSe/PbOx heterostructures and discover superconductivities in three different monolayer FeSe-related interfaces. We observe superconducting gaps of 13~14 meV in the monolayer FeSe films grown on two different phases of PbOx. Moreover, we discover a new insulating Fe10Se9 phase with an ordered \(\sqrt{5}\times\sqrt{5}\) Se-vacancy structure. Our first-principles calculation suggests that this new insulating phase originates from electronic correlation. Intriguingly, an additional monolayer FeSe film grown on the insulating Fe10Se9 also exhibits superconductivity with the gap size of 5 meV. Our results suggest that the work function differences between the monolayer FeSe and the substrates, which can induce band bending and charge transfer, are crucial for the interfacial superconductivity.
Superconductivity (cond-mat.supr-con)
8 pages, 4 figures
State- and momentum-dependent nonlinear Stark effect of interlayer excitons in bilayer WSe\(_2\)
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Cem Sevik, Engin Torun, Milorad V. Milosevic, Fulvio Paleari
Interlayer excitons in van der Waals heterostructures offer rich collective phases, prospective optoelectronic applications, and versatile tunability, where control by electronic means is particularly relevant and practical. Here, in the case of bilayer WSe\(_2\), we reveal how layer localization of excitons governs their response to an external electric field. Using Many-Body Perturbation Theory, we calculate the exciton dispersion for different stacking symmetries under applied electric field and/or strain, in order to map the landscape of competing low-energy excitons in four distinct finite-momentum valleys. While intralayer excitons are not affected by the electric field, some interlayer ones exhibit a nonlinear Stark shift that becomes linear after a critical threshold. The degree of nonlinearity is a direct measure of the layer hybridization of the electronic subcomponents of the exciton. Our findings explain the peculiar Stark-shift regimes observed in recent experiments, the nature of (anti)symmetric spectral shifts around zero field, and the sensitivity of dipolar excitons to external perturbations, all highly relevant to their further applications in excitonic condensates, optoelectronics devices and quantum emitters.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
Elastically Buckled Film-Substrate System as a Two-dimensional Crystal
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Compressive mechanical stress exceeding a critical value leads to the formation of periodic surface buckling patterns in film-substrate systems. A comprehensive understanding of this buckling phenomenon is desired in applications where the surface topologies are modulated to achieve multifunctionalities. Here we reformulate the finite-deformation elastic theory of a film-substrate system by treating the compliant substrate as a nonlinear elastic solid. The resulting elastic free energy functional of the deflection field is shown to be equivalent to a minimal density functional of phase-field crystal theory plus a Gaussian curvature-related term. The proposed elastic model constructs a phase diagram based on free energy minimization, quantitatively agreeing with the buckling transitions observed in former experiments. The emerging hexagonal buckling system is shown to be equivalent to a two-dimensional crystal with proper scalings. We further conducted simulations of repeated buckling under cyclic stress to demonstrate a dynamically modulated structural adhesive, which resembles the physical process of repeated crystallization and melting near a critical temperature.
Materials Science (cond-mat.mtrl-sci)
13 pages, 4 figures
Symmetries at the Anderson transition of correlated two-dimensional electrons
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-20 20:00 EST
Mathieu Lizée, Mohammadmehdi Torzadeh, François Debontridder, Marie Hervé, Christophe Brun, Tristan Cren
The interplay between Anderson localization and Coulomb repulsion reveals deep connections to superconductivity and many-body localization in quantum systems. In this study, we investigate a tin monolayer on silicon, a material known for its Mott and antiferromagnetic behavior, as it undergoes a metal-insulator transition near a band edge. By analyzing spatial correlations of the local density of states (LDOS) with scanning tunneling spectroscopy, we precisely identify the mobility edge and determine its critical exponent as nu = 0.75 +/- 0.1. Our findings show that both LDOS distribution functions and multifractal spectra obey two exact symmetry relations based on the Weyl group symmetry of nonlinear sigma-models. These symmetries hold across the entire transition, from extended to strongly localized states, in agreement with theoretical predictions. Additionally, we observe a power-law scaling of LDOS fluctuations close to the band edge (power -1.7), deep in the localized regime. Using tight-binding models, we demonstrate that breaking time-reversal symmetry significantly improves the agreement between our experimental data and theory compared to the standard Anderson model. Overall, our results provide a unifying framework for understanding localization at the band gap edge of a strongly correlated 2D material and show how localization patterns reflect the symmetry class of disordered electronic systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 4 figures
AI-Driven Discovery of High Performance Polymer Electrodes for Next-Generation Batteries
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-20 20:00 EST
Subhash V.S. Ganti, Lukas Woelfel, Christopher Kuenneth
The use of transition group metals in electric batteries requires extensive usage of critical elements like lithium, cobalt and nickel, which poses significant environmental challenges. Replacing these metals with redox-active organic materials offers a promising alternative, thereby reducing the carbon footprint of batteries by one order of magnitude. However, this approach faces critical obstacles, including the limited availability of suitable redox-active organic materials and issues such as lower electronic conductivity, voltage, specific capacity, and long-term stability. To overcome the limitations for lower voltage and specific capacity, a machine learning (ML) driven battery informatics framework is developed and implemented. This framework utilizes an extensive battery dataset and advanced ML techniques to accelerate and enhance the identification, optimization, and design of redox-active organic materials. In this contribution, a data-fusion ML coupled meta learning model capable of predicting the battery properties, voltage and specific capacity, for various organic negative electrodes and charge carriers (positive electrode materials) combinations is presented. The ML models accelerate experimentation, facilitate the inverse design of battery materials, and identify suitable candidates from three extensive material libraries to advance sustainable energy-storage technologies.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG), Applied Physics (physics.app-ph)
33 pages, 10 figures, 3 tables
Quorum sensing and absorbing phase transitions in colloidal active matter
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-20 20:00 EST
Thibault Lefranc, Alberto Dinelli, Carla Fernandez Rico, Roel P. A. Dullens, Julien Tailleur, Denis Bartolo
Unlike biological active matter that constantly adapt to their environment, the motors of synthetic active particles are typically agnostic to their surroundings and merely operate at constant force. Here, we design colloidal active rods capable of modulating their inner activity in response to crowding, thereby enforcing a primitive form of quorum sensing interactions. Through experiments, simulations and theory we elucidate the impact of these interactions on the phase behavior of isotropic active matter. We demonstrate that, when conditioned to density, motility regulation can either lead to an absorbing phase transition, where all particles freeze their dynamics, or to atypical phase separation, where flat interfaces supporting a net pressure drop are in mechanical equilibrium. Fully active and fully arrested particles can then form heterogeneous patterns ruled by the competition between quorum sensing and mechanical interactions. Beyond the specifics of motile colloids, we expect our findings to apply broadly to adaptive active matter assembled from living or synthetic units.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
12 pages, 6 figures
Local and Non-local Entanglement Witnesses of Fermi Liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
Yiming Wang, Yuan Fang, Fang Xie, Qimiao Si
There is a growing interest both in utilizing entanglement means to characterize many-body systems and in uncovering their entanglement depth. Motivated by recent findings that the spin quantum Fisher information witnesses amplified multipartite entanglement of strange metals and characterizes their loss of quasiparticles, we study the quantum Fisher information in various cases of Fermi liquid. We show that local operators generically do not witness any multipartite entanglement in a Fermi liquid, but non-local many-body operators do. Our results point to novel experimental means to detect the entanglement depth of metallic fermionic systems and, in general, open a new avenue to the emerging exploration of entanglement in quantum materials.
Strongly Correlated Electrons (cond-mat.str-el)
6+8 pages, 4+1 figures
Extended \(s\)-wave pairing from an emergent Feshbach resonanc in bilayer nickelate superconductors
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-20 20:00 EST
Pietro Borchia, Hannah Lange, Fabian Grusdt
Since the discovery of unconventional superconductivity in cuprates, unraveling the pairing mechanism of charge carriers in doped antiferromagnets has been a long-standing challenge. Motivated by the discovery of high-T\(_c\) superconductivity in nickelate bilayer La\(_3\)Ni\(_2\)O\(_7\) (LNO), we study a minimal mixed dimensional (MixD) \(t-J\) model supplemented with a repulsive Coulomb interaction \(V\). When hole-doped, previous numerical simulations revealed that the system exhibits strong binding energies, with a phenomenology resembling a BCS-to-BEC crossover accompanied by a Feshbach resonance between two distinct types of charge carriers. Here, we perform a mean-field analysis that enables a direct observation of the BCS-to-BEC crossover as well as microscopic insights into the crossover region and the pairing symmetry for two-dimensional bilayers. We benchmark our mean-field description by comparing it to density-matrix renormalization group (DMRG) simulations in quasi-one dimensional settings and find remarkably good agreement. For the two-dimensional system relevant to LNO our mean-field calculations predict a BCS pairing gap with an extended \(s\)-wave symmetry, directly resulting from the pairing mechanism's Feshbach-origin. Our analysis hence gives insights into pairing in unconventional superconductors and, further, can be tested in currently available ultracold atom experiments.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Gases (cond-mat.quant-gas)
14 pages, 7 figures