CMP Journal 2025-02-17
Statistics
Nature: 2
Nature Materials: 2
Nature Physics: 1
arXiv: 55
Nature
Ambient-pressure superconductivity onset above 40 K in (La,Pr)3Ni2O7 films
Original Paper | Superconducting properties and materials | 2025-02-16 19:00 EST
Guangdi Zhou, Wei Lv, Heng Wang, Zihao Nie, Yaqi Chen, Yueying Li, Haoliang Huang, Weiqiang Chen, Yujie Sun, Qi-Kun Xue, Zhuoyu Chen
The discovery of bilayer nickelate superconductors under high pressure has opened a new chapter in high-transition temperature (high-TC) superconductivity1-8. However, the high-pressure condition and presence of impurity phases have hindered comprehensive investigations into their superconducting properties and potential applications. Here, we report ambient-pressure superconductivity onset above the McMillan limit (40 K) in bilayer nickelate epitaxial thin films. Three-unit-cell (3UC) thick La2.85Pr0.15Ni2O7 pure-phase single-crystal films are grown using the gigantic-oxidative atomic-layer-by-layer epitaxy (GOALL-Epitaxy) on SrLaAlO4 substrates9. Resistivity measurements and magnetic-field responses indicate onset TC = 45 K. The transition to zero resistance exhibits characteristics consistent with a Berezinskii-Kosterlitz-Thouless (BKT)-like behavior, with TBKT = 9 K. Meissner diamagnetic effect is observed at TM = 8 K via a mutual inductance setup, in agreement with the BKT-like transition. In-plane and out-of-plane critical magnetic fields exhibit anisotropy. Scanning transmission electron microscopy (STEM) images and X-ray reciprocal space mappings (RSMs) reveal that the bilayer nickelate films adopt a tetragonal phase under ~2% coherent epitaxial compressive strain in the NiO2 planes relative to the bulk. Our findings pave the way for comprehensive investigations of nickelate superconductors under ambient pressure conditions and for exploring superconductivity at higher transition temperature through strain engineering in heterostructures.
Superconducting properties and materials, Surfaces, interfaces and thin films
Characterization of single neurons reprogrammed by pancreatic cancer
Original Paper | Pancreas | 2025-02-16 19:00 EST
Vera Thiel, Simon Renders, Jasper Panten, Nicolas Dross, Katharina Bauer, Daniel Azorin, Vanessa Henriques, Vanessa Vogel, Corinna Klein, Aino-Maija Leppä, Isabel Barriuso Ortega, Jonas Schwickert, Iordanis Ourailidis, Julian Mochayedi, Jan-Philipp Mallm, Carsten Müller-Tidow, Hannah Monyer, John Neoptolemos, Thilo Hackert, Oliver Stegle, Duncan T. Odom, Rienk Offringa, Albrecht Stenzinger, Frank Winkler, Martin Sprick, Andreas Trumpp
The peripheral nervous system (PNS) orchestrates organ function in health and disease. Most cancers including pancreatic ductal adenocarcinoma (PDAC) are infiltrated by PNS neurons, contributing to the complex tumor microenvironment (TME)1,2. However, neuronal cell bodies reside in various PNS ganglia, far from the tumor mass. Thus, cancer or healthy organ-innervating neurons elude current tissue sequencing datasets. To molecularly characterize pancreas- and PDAC-innervating neurons at single cell resolution, we developed "Trace-n-seq". This method employs retrograde tracing of axons from tissues to their respective ganglia followed by single-cell isolation and transcriptomic analysis. By characterizing >5.000 individual sympathetic and sensory neurons with about 4.000 innervating PDAC or healthy pancreas we reveal novel neuronal cell types and unique molecular networks distinct to pancreas, pancreatitis, PDAC, or melanoma metastasis. We integrate single-cell datasets of innervating neurons and the TME to establish a neuro-cancer-microenvironment interactome, delineate cancer-driven neuronal reprogramming and generate a pancreatic cancer-nerve signature. Pharmacological denervation induces a proinflammatory TME and increases immune-checkpoint inhibitor effectiveness. Nab-Paclitaxel causes intra-tumor neuropathy which attenuated PDAC growth and in combination with sympathetic denervation results in synergistic tumor regression. Our multi-dimensional data reveal new insights into the networks and functions of PDAC-innervating neurons, supporting inclusion of denervation in future therapies.
Pancreas, Pancreatic cancer, Peripheral nervous system, Preclinical research
Nature Materials
Blood-brain-barrier-crossing lipid nanoparticles for mRNA delivery to the central nervous system
Original Paper | Biomaterials | 2025-02-16 19:00 EST
Chang Wang, Yonger Xue, Tamara Markovic, Haoyuan Li, Siyu Wang, Yichen Zhong, Shi Du, Yuebao Zhang, Xucheng Hou, Yang Yu, Zhengwei Liu, Meng Tian, Diana D. Kang, Leiming Wang, Kaiyuan Guo, Dinglingge Cao, Jingyue Yan, Binbin Deng, David W. McComb, Ramon E. Parsons, Angelica M. Minier-Toribio, Leanne M. Holt, Jiayi Pan, Alice Hashemi, Brian H. Kopell, Alexander W. Charney, Eric J. Nestler, Paul C. Peng, Yizhou Dong
The systemic delivery of mRNA molecules to the central nervous system is challenging as they need to cross the blood-brain barrier (BBB) to reach into the brain. Here we design and synthesize 72 BBB-crossing lipids fabricated by conjugating BBB-crossing modules and amino lipids, and use them to assemble BBB-crossing lipid nanoparticles for mRNA delivery. Screening and structure optimization studies resulted in a lead formulation that has substantially higher mRNA delivery efficiency into the brain than those exhibited by FDA-approved lipid nanoparticles. Studies in distinct mouse models show that these BBB-crossing lipid nanoparticles can transfect neurons and astrocytes of the whole brain after intravenous injections, being well tolerated across several dosage regimens. Moreover, these nanoparticles can deliver mRNA to human brain ex vivo samples. Overall, these BBB-crossing lipid nanoparticles deliver mRNA to neurons and astrocytes in broad brain regions, thereby being a promising platform to treat a range of central nervous system diseases.
Biomaterials, Nanoscience and technology
Lean design of a strong and ductile dual-phase titanium-oxygen alloy
Original Paper | Materials science | 2025-02-16 19:00 EST
Wangwang Ding, Qiying Tao, Chang Liu, Gang Chen, SangHyuk Yoo, Wei Cai, Peng Cao, Baorui Jia, Haoyang Wu, Deyin Zhang, Hongmin Zhu, Lin Zhang, Xuanhui Qu, Jin Zou, Mingli Qin
Unalloyed titanium boasts an impressive combination of ductility, biocompatibility and corrosion resistance. However, its strength properties are moderate, which constrains its use in demanding structural applications. Traditional alloying methods used to strengthen titanium often compromise ductility and tend to be costly and energy intensive. Here we present a lean alloy design approach to create a strong and ductile dual-phase titanium-oxygen alloy. By embedding a coherent nanoscale allotropic face-centred cubic titanium phase into the hexagonal close-packed titanium matrix, we significantly enhance strength while preserving substantial ductility. This hexagonal-close-packed/face-centred-cubic dual-phase titanium-oxygen alloy is created by leveraging the tailored oxide-layer thickness of the powders and the rapid cooling inherent in laser-based powder bed fusion. The as-printed Ti-0.67 wt% O alloy exhibits an ultimate tensile strength of 1,119.3 ± 29.2 MPa and a ductility of 23.3 ± 1.9%. Our strategy of incorporating a coherent nanoscale allotropic phase offers a promising pathway to developing high-performance, cost-effective and sustainable lean alloys.
Materials science, Structural materials
Nature Physics
Pressure-enhanced splitting of density wave transitions in La3Ni2O7-δ
Original Paper | Magnetic properties and materials | 2025-02-16 19:00 EST
Rustem Khasanov, Thomas J. Hicken, Dariusz J. Gawryluk, Vahid Sazgari, Igor Plokhikh, Loïc Pierre Sorel, Marek Bartkowiak, Steffen Bötzel, Frank Lechermann, Ilya M. Eremin, Hubertus Luetkens, Zurab Guguchia
The observation of superconductivity in La3Ni2O7-δ under pressure, following the suppression of a high-temperature density wave state, has attracted considerable attention. The nature of this density wave order was not clearly identified. Here we probe the magnetic response of the zero-pressure phase of La3Ni2O7-δ as hydrostatic pressure is applied, and find that the apparent single density wave transition at zero applied pressure splits into two. The comparison of our muon-spin rotation and relaxation experiments with dipole-field numerical analysis reveals the magnetic structure's compatibility with a stripe-type arrangement of Ni moments, characterized by alternating lines of magnetic moments and non-magnetic stripes at ambient pressure. When pressure is applied, the magnetic ordering temperature increases, whereas the unidentified density wave transition temperature falls. Our findings reveal that the ground state of the La3Ni2O7-δ system is characterized by the coexistence of two distinct orders--a magnetically ordered spin density wave and a lower-temperature ordering that is most probably a charge density wave--with a notable pressure-enhanced separation between them.
Magnetic properties and materials, Superconducting properties and materials
arXiv
On the Jump Conditions for Shock Waves in Condensed Materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
In this article, we have proposed Rankine-Hugoniot (RH) boundary conditions at the normal shock front, which is passing through the condensed material. These RH conditions are quite general, and their convenient forms for the particle velocity, mass density, pressure, and temperature have been presented in terms of the upstream Mach number and the material parameters for the weak and the strong shocks, respectively. Finally, the effects on the mechanical quantities of the shock-compressed materials, e.g., titanium Ti6Al4V, stainless steel 304, aluminum 6061-T6, etc., have been discussed.
Materials Science (cond-mat.mtrl-sci), High Energy Astrophysical Phenomena (astro-ph.HE), Applied Physics (physics.app-ph)
10 pages, 3 figures and 2 tables
Lattice Schwinger Model and Spacetime Supersymmetry
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-17 20:00 EST
Gauge theories in (1+1)D have attracted renewed attention partially due to their experimental realizations in quantum simulation platforms. In this work, we revisit the lattice massive Schwinger model and the (1+1)D lattice Abelian-Higgs model, uncovering previously overlooked universal features, including the emergence of a supersymmetric quantum critical point when the Maxwell term's coefficient changes sign. To facilitate the quantum simulation of these theories, we adopt a strategy of truncating the electric field eigenvalues to a finite subset, preserving the exact gauge and global symmetries. Our primary focus is the truncated lattice Schwinger model at \(\theta=0\), a model not equivalent to familiar spin models. We find that upon reversing the sign of the Maxwell term, the second-order deconfinement-confinement transition can become first-order, and the two types of transitions are connected by a supersymmetric critical point in the tricritical Ising universality class. In the case of truncated abelian-Higgs model at \(\theta=0\), which turns out to be equivalent to the quantum Blume-Capel model, the very existence of a deconfined phase requires a negative-sign Maxwell term. Similarly, there is a tricritical Ising point separating first-order and second-order phase transitions.
Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Lattice (hep-lat), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
5+4 pages, 5 figures
Fractionalized Prethermalization in the One-Dimensional Hubbard Model
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Anton Romen, Johannes Knolle, Michael Knap
Prethermalization phenomena in driven systems are generally understood via a local Floquet Hamiltonian obtained from a high-frequency expansion. Remarkably, recently it has been shown that a driven Kitaev spin liquid with fractionalized excitations can realize a quasi-stationary state that is not captured by this paradigm. Instead distinct types of fractionalized excitations are characterized by vastly different temperatures-a phenomenon dubbed "fractionalized prethermalization". In our work, we analyze fractionalized prethermalization in a driven one-dimensional Hubbard model at strong coupling which hosts spin-charge fractionalization. At intermediate frequencies quasi-steady states emerge which are characterized by a low spin and high charge temperature with lifetimes set by two competing processes: the lifetime of the quasiparticles determined by Fermi's Golden rule and the exponential lifetime of the Floquet prethermal plateau. We classify drives into three categories, each giving rise to distinct (fractional) prethermalization dynamics. Resorting to a time-dependent variant of the Schrieffer-Wolff transformation, we systematically analyze how these drive categories are linked to the underlying driven Hubbard model, thereby providing a general understanding of the emergent thermalization dynamics. We discuss routes towards an experimental realization of this phenomenon in quantum simulation platforms.
Strongly Correlated Electrons (cond-mat.str-el)
17 pages, 10 figures
Fading ergodicity meets maximal chaos
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-17 20:00 EST
Rafał Świętek, Patrycja Łydżba, Lev Vidmar
Fading ergodicity provides a theoretical framework for understanding deviations from the eigenstate thermalization hypothesis (ETH) near ergodicity-breaking transitions. In this work, we demonstrate that the breakdown of the ETH at the interaction-driven ergodicity-breaking critical point in the quantum sun model gives rise to to the maximally divergent fidelity susceptibility. We further extend our analysis to the energy-driven ergodicity-breaking transition associated with the many-body mobility edge. Specifically, we show that fidelity susceptibilities at energies away from the middle of the spectrum exhibit a divergent peak near the mobility edge. Finally, we argue that fading ergodicity provides a simple and accurate description of the ETH breakdown in the quantum sun model, which is accompanied with the emergence of a peak in fidelity susceptibility and the onset of maximal chaos at the ergodicity-breaking critical point.
Statistical Mechanics (cond-mat.stat-mech), Disordered Systems and Neural Networks (cond-mat.dis-nn), Strongly Correlated Electrons (cond-mat.str-el), High Energy Physics - Theory (hep-th), Quantum Physics (quant-ph)
Imaging orbital Rashba induced charge transport anisotropy
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Eylon Persky, Xi Wang, Giacomo Sala, Thierry C. van Thiel, Edouard Lesne, Alexander Lau, Mario Cuoco, Marc Gabay, Carmine Ortix, Andrea D. Caviglia, Beena Kalisky
Identifying orbital textures and their effects on the electronic properties of quantum materials is a critical element in developing orbitronic devices. However, orbital effects are often entangled with the spin degree of freedom, making it difficult to uniquely identify them in charge transport phenomena. Here, we present a combination of scanning superconducting quantum interference device (SQUID) current imaging, global transport measurements, and theoretical analysis, that reveals a direct contribution of orbital textures to the linear charge transport of 2D systems. Specifically, we show that in the LaAlO\(_3\)/SrTiO\(_3\) interface, which lacks both rotation and inversion symmetries, an anisotropic orbital Rashba coupling leads to conductivity anisotropy in zero magnetic field. We experimentally demonstrate this result by locally measuring the conductivity anisotropy, and correlating its appearance to the non-linear Hall effect, showing that the two phenomena have a common origin. Our results lay the foundations for an all--electrical probing of orbital currents in two-dimensional systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
22 pages, 15 figures
Spin liquid state in Y-Kapellasite, Y\(_3\)Cu\(_9\)(OH)\(_{19}\)Cl\(_8\) by external pressure controlled frustration
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Dipranjan Chatterjee, Petr Doležal, Federico Abbruciati, Tobias Biesner, Katharina M. Zoch, Rustem Khasanov, Shams Sohel Islam, Guratinder Kaur, Seulki Roh, Francesco Capitani, Gaston Garbarino, Cornelius Krellner, Philippe Mendels, Edwin Kermarrec, Martin Dressel, Björn Wehinger, Andrej Pustogow, Fabrice Bert, Pascal Puphal
Magnetic frustration is a key ingredient to prevent conventional ordering and, in combination with enhanced fluctuations in low dimensional quantum magnets, to stabilize the long sought spin liquid ground states. Most experimental spin liquid candidates inevitably deviate from perfectly frustrated models due to chemical and structural disorder, blurring the nature and origin of their ground states. Y-Kapellasite Y\(_3\)Cu\(_9\)(OH)\(_{19}\)Cl\(_{8}\) realizes a chemically clean system with an underlying kagome sub-lattice. The crystals undergo the theoretically predicted magnetic in-plane (1/3 1/3) order from a subtle release of frustration due to a distortion of the kagome system realised by displaced Y atoms. By studying the effect of pressure on the structure and optical phonons, we show that this distortion is partially lifted by compression towards a more isotropic model of interactions, in a gradual manner, without structural transition. Using \(\mu\)SR, we further show that the magnetic ground state is surprisingly sensitive to the applied pressure for a mineral, and that under a moderate 2 GPa pressure, the frustration increase is sufficient to induce a fluctuating ground state. Suppressing long-range magnetic order via frustration tuning with pressure, in an ultraclean material, establishes a major step towards realizing a well-controlled spin liquid ground state.
Strongly Correlated Electrons (cond-mat.str-el)
18 pages, 11 figures
Quantifying the Complexity of Materials with Assembly Theory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Keith Y Patarroyo, Abhishek Sharma, Ian Seet, Ignas Packmore, Sara I. Walker, Leroy Cronin
Quantifying the evolution and complexity of materials is of importance in many areas of science and engineering, where a central open challenge is developing experimental complexity measurements to distinguish random structures from evolved or engineered materials. Assembly Theory (AT) was developed to measure complexity produced by selection, evolution and technology. Here, we extend the fundamentals of AT to quantify complexity in inorganic molecules and solid-state periodic objects such as crystals, minerals and microprocessors, showing how the framework of AT can be used to distinguish naturally formed materials from evolved and engineered ones by quantifying the amount of assembly using the assembly equation defined by AT. We show how tracking the Assembly of repeated structures within a material allows us formalizing the complexity of materials in a manner accessible to measurement. We confirm the physical relevance of our formal approach, by applying it to phase transformations in crystals using the HCP to FCC transformation as a model system. To explore this approach, we introduce random stacking faults in closed-packed systems simplified to one-dimensional strings and demonstrate how Assembly can track the phase transformation. We then compare the Assembly of closed-packed structures with random or engineered faults, demonstrating its utility in distinguishing engineered materials from randomly structured ones. Our results have implications for the study of pre-genetic minerals at the origin of life, optimization of material design in the trade-off between complexity and function, and new approaches to explore material technosignatures which can be unambiguously identified as products of engineered design.
Materials Science (cond-mat.mtrl-sci)
34 pages, 7 figures, 55 references
Skyrmion-Skyrmionium Phase Separation and Laning Transitions via Spin-Orbit Torque Currents
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
N. P. Vizarim, J. C. Bellizotti Souza, C. J. O. Reichhardt, C. Reichhardt, P. A. Venegas, F. Béron
Many driven binary systems can exhibit laning transitions when the two species have different mobilities, such as colloidal particles with opposite charges in electric fields. Another example is pedestrian or active matter systems, where particles moving in opposite directions form a phase-separated state that enhances the overall mobility. In this work, we use atomistic simulations to demonstrate that mixtures of skyrmions and skyrmioniums also exhibit pattern formation and laning transitions. Skyrmions move more slowly and at a finite Hall angle compared to skyrmioniums, which move faster and without a Hall effect. At low drives, the system forms a partially jammed phase where the skyrmionium is dragged by the surrounding skyrmions, resulting in a finite angle of motion for the skyrmionium. At higher drives, the system transitions into a laned state, but unlike colloidal systems, the lanes in the skyrmion skyrmionium mixture are tilted relative to the driving direction due to the intrinsic skyrmion Hall angle. In the laned state, the skyrmionium angle of motion is reversed when it aligns with the tilted lane structure. At even higher drives, the skyrmioniums collapse into skyrmions. Below a critical skyrmion density, both textures can move independently with few collisions, but above this density, the laning state disappears entirely, and the system transitions to a skyrmion-only state. We map out the velocity and Hall responses of the different textures and identify three distinct phases: partially jammed, laned, and skyrmion-only moving crystal states. We compare our results to recent observations of tilted laning phases in pedestrian flows, where chiral symmetry breaking in the particle interactions leads to similar behavior.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
11 pages, 13 figures
Effect of hole-strain coupling on the eigenmodes of semiconductor-based nanomechanical systems
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Electron-phonon coupling can strongly affect the eigenmodes of nano- and micromechanical resonators. We study the effect of the coupling for \(p\)-doped semiconductor resonators. We show that the backaction from the strain-induced redistribution of the holes between and within the energy bands can lead to a nonmonotonic dependence of the modes' eigenfrequencies on temperature and to a strong mode nonlinearity that also nonmonotonically depends on temperature. Unexpectedly, we find that the nonlinearity can nonmonotonically depend on the hole density. We also briefly discuss the effect of the coupling to holes on the modes' decay rates. The results are compared with the experiment.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Bound states in the continuum in cuprous oxide quantum wells
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Angelos Aslanidis, Jörg Main, Patric Rommel, Stefan Scheel, Pavel A. Belov
We propose a realistic semiconductor system containing bound states in the continuum (BICs) which allows for a practical realization. By varying the confinement strength of excitons in cuprous oxide quantum wells, we show that long-lived Rydberg states of the confined electron-hole pairs appear in the continuum background. The accuracy of calculations of the linewidths based on the coupled-channel Schrödinger equation with three channels and only few basis states is confirmed by a numerically exact solution employing a B-spline basis and the complex coordinate-rotation method. We argue that finite-sized cuprous oxide crystals, due to their large exciton binding energies, are a convenient platform for experimental identification of BICs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
6 pages, 4 figures (paper) + 4 pages, 1 figure (supplemental material), submitted to Phys. Rev. B
Atom identification in bilayer moire materials with Gomb-Net
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Austin C. Houston, Sumner B. Harris, Hao Wang, Yu-Chuan Lin, David B. Geohegan, Kai Xiao, Gerd Duscher
Moire patterns in van der Waals bilayer materials complicate the analysis of atomic-resolution images, hindering the atomic-scale insight typically attainable with scanning transmission electron microscopy. Here, we report a method to detect the positions and identity of atoms in each of the individual layers that compose bilayer heterostructures. We developed a deep learning model, Gomb-Net, which can distinguish atomic species in each individual layer, effectively deconvoluting the moire pattern to enable layer-specific mapping of strain and dopant distributions, unlike other methods which struggle with moire-induced complexity. Using this approach, we explored Se atom substitutional sites in a twisted fractional Janus WS2-WS2(1-x)Se2x heterostructure and found that layer specific implantation sites are unaffected by the moire pattern's local energetic or electronic modulation. This advancement enables atom-identification within material regimes where it was not possible before, opening new insights into previously inaccessible material physics.
Materials Science (cond-mat.mtrl-sci), Computer Vision and Pattern Recognition (cs.CV)
Exploring the mechanism of phase transitions between the hexagonal close-packed and the cuboidal structures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Andres Robles-Navarro, Shaun Cooper, Odile R. Smits, Peter Schwerdtfeger
By introducing appropriate lattice parameters for a bi-lattice smoothly connecting the hexagonal close-packed (hcp) with the cuboidal structures, namely the body-centered (bcc) and the face centered cubic (fcc) lattices, we were able to map out the minimum energy path for a Burgers-Bain type of phase transition. We demonstrate that for three different models applied, i.e. the kissing hard-sphere model, the Lennard-Jones potential, and density functional theory for metallic lithium, the direct transition path is always from hcp to fcc with a separate path leading from fcc to bcc. This solves, at least for the models considered here, a long-standing controversy of whether or not fcc acts as an intermediate phase in martensitic type of phase transitions.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Atomic Fermi superfluids with tunable pairing interactions under the influence of spin-dependent Rydberg molecular potentials
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-17 20:00 EST
Chih-Chun Chien, Seth T. Rittenhouse, S. I. Mistakidis, H. R. Sadeghpour
We explore the energy spectrum and eigenstates of two-component atomic Fermi superfluids with tunable pairing interactions in the presence of spin-dependent ultra long-range Rydberg molecule (ULRM) potentials, within the Bogoliubov-de Gennes formalism. The attractive ULRM potentials lead to local density accumulation, while their difference results in a local polarization potential and induces the in-gap Yu-Shiba-Rusinov (YSR) states whose energies lie below the bulk energy gap. A transition from equal-population to population-imbalance occurs as the pairing strength falls below a critical value, accompanied by the emergence of local Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) like states characterized by out-of-phase wave functions and lower energies compared to the YSR states. The negative contribution emanating from the FFLO-like states also causes a sign change in the gap function within the ULRM potentials. Depending on the Rydberg state generating the ULRM potentials, the transition towards population-imbalance can be on either the BCS or the Bose-Einstein condensation side of the Fermi superfluid. Additionally, spin-polarized bound states arise along with oscillatory ``clumpy states" to compensate for the local density difference. Finally, we discuss possible experimental realizations and measurements of the composite Rydberg atom-Fermi superfluid system.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
12 pages, 7 figures, submitted
Direct experimental measurement of many-body hydrodynamic interactions with optical tweezers
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-17 20:00 EST
Dae Yeon Kim, Sachit G. Nagella, Kyu Hwan Choi, Sho C. Takatori
Many-body hydrodynamic interactions (HIs) play an important role in the dynamics of fluid suspensions. While many-body HIs have been studied extensively using particle simulations, there is a dearth of experimental frameworks with which to quantify fluid-mediated multi-body interactions. To address this, we design an experimental method that utilizes optical laser tweezers for quantifying fluid-mediated colloidal interactions with exquisite precision and control. By inducing translation-rotation hydrodynamic coupling between trapped fluorescently-labeled colloids, we obtain a direct reporter of few- to many-body HIs experimentally. We leverage the torque-free nature of laser tweezers to enable sensitive measurements of signals between trapped colloids. First, we measure the pair HI between a stationary tracer probe and a translating particle as a function of their separation distance. We discover that our technique can precisely quantify distant fluid disturbances that are generated by ~2 pN of hydrodynamic force at 12 particle radii of separation. To study the effect of many-body HIs, we measure the rotational mobility of a probe in a three-particle setup and in a model material, a two-dimensional hexagonally-close-packed lattice, that undergoes oscillatory strain. Respectively, we discover that the probe's rotation can reverse in certain three-body configurations, and we find that rotational mobility in the crystalline array is strongly attenuated by particle rigidity. Experimental measurements are corroborated by microhydrodynamic theory and Stokesian Dynamics simulations with excellent agreement, highlighting our ability to measure accurately many-body HIs. Lastly, we extend our theoretical framework to manipulate colloidal-scale fluid flows. With experimental validation, we compute the required trajectory of a moving particle to induce a desired angular velocity of a probe.
Soft Condensed Matter (cond-mat.soft)
Strain energy enhanced room-temperature magnetocaloric effect in second-order magnetic transition materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Xiaohe Liu, Ping Song, Sen Yao, Yuhao Lei, Ling Yang, Shenxiang Du, Yiran Deng, Defeng Guo
Large magnetic entropy change (deltaSM) can realize a prominent heat transformation under the magnetic field and directly strengthen the efficacy of the magnetocaloric effect, which provides a pioneering environmentally friendly solid-state strategy to improve refrigeration capacities and efficiencies. The second-order magnetic transition (SOMT) materials have broader deltaSM peaks without thermal hysteresis compared with most first-order magnetic transition materials, making them highly attractive in magnetic refrigeration, especially in the room temperature range. Here, we report a significant enhancement of deltaSM at room temperature in single-crystal Mn5Ge3. In this SOMT system, we realize a 60% improvement of -deltaSM from 3.5 J/kgK to 5.6 J/kgK at T = 300K. This considerable enhancement of deltaSM is achieved by intentionally introducing strain energy through high-pressure constrained deformation. Both experimental results and Monte Carlo simulations demonstrate that the enhancement of deltaSM originates from the microscopic strain and lattice deformation induced by strain energy after deformation. This strain energy will reconstruct the energy landscape of this ferromagnetic system and enhance magnetization, resulting in a giant intensity of magnetocaloric responses. Our findings provide an approach to increase magnetic entropy change and may give fresh ideas for exploring advanced magnetocaloric materials.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Unveiling resilient superconducting fluctuations in atomically thin NbSe\(_2\) through Higgs mode spectroscopy
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-17 20:00 EST
Yu Du, Gan Liu, Wei Ruan, Zhi Fang, Kenji Watanabe, Takashi Taniguchi, Ronghua Liu, Jian-Xin Li, Xiaoxiang Xi
We report a combined electrical transport and optical study of the superconductivity in atomically thin NbSe\(_2\). When subjected to an out-of-plane magnetic field, an anomalous metallic state emerges, characterized by a finite longitudinal resistance and a vanishing Hall resistance, suggesting the presence of particle-hole symmetry. We establish a superconducting Higgs mode in atomically thin samples, which reveals enduring superconducting fluctuations that withstand unexpectedly high reduced magnetic fields. These findings provide evidence of robust locally paired electrons in the anomalous metallic state, affirming its bosonic nature.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phys. Rev. Lett. 134, 066002 (2025)
Superconductivity and a van Hove singularity confined to the surface of a topological semimetal
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-17 20:00 EST
Md Shafayat Hossain, Rajibul Islam, Zi-Jia Cheng, Zahir Muhammad, Qi Zhang, Zurab Guguchia, Jonas A. Krieger, Brian Casas, Yu-Xiao Jiang, Maksim Litskevich, Xian P. Yang, Byunghoon Kim, Tyler A. Cochran, Ilias E. Perakis, Fei Xue, Mehdi Kargarian, Weisheng Zhao, Luis Balicas, M. Zahid Hasan
The interplay between electronic topology and superconductivity is the subject of great current interest in condensed matter physics. For example, superconductivity induced on the surface of topological insulators is predicted to be triplet in nature, while the interplay between electronic correlations and topology may lead to unconventional superconductivity as in twisted bilayer graphene. Here, we unveil an unconventional two-dimensional superconducting state in the recently discovered Dirac nodal line semimetal ZrAs2 which is exclusively confined to the top and bottom surfaces within the crystal's ab plane. As a remarkable consequence of this emergent state, we observe a Berezinskii-Kosterlitz-Thouless (BKT) transition, the hallmark of two-dimensional superconductivity. Notably, this is the first observation of a BKT transition on the surface of a three-dimensional system. Furthermore, employing angle-resolved photoemission spectroscopy and first-principles calculations, we find that these same surfaces also host a two-dimensional van Hove singularity near the Fermi energy. The proximity of van Hove singularity to the Fermi level leads to enhanced electronic correlations contributing to the stabilization of superconductivity at the surface of ZrAs2, a unique phenomenon among topological semimetals. The surface-confined nature of the van Hove singularity, and associated superconductivity, realized for the first time, opens new avenues to explore the interplay between low-dimensional quantum topology, correlations, and superconductivity in a bulk material without resorting to the superconducting proximity effect.
Superconductivity (cond-mat.supr-con), Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el), Applied Physics (physics.app-ph)
in press
Nature Communications (2025)
Spin separation and filtering assisted by topological corner states in the Kekulé lattice
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Kai-Tong Wang, Hui Wang, Shijie Liu, Miaomiao Wei, Fuming Xu
Higher-order topological corner states have been realized in two-dimensional Kekulé lattice, which can be further coupled with spin polarization through the implementation of local magnetization. In this work, we numerically investigate the spin-dependent transport properties assisted by topological corner states in the Kekulé lattice. By applying local magnetization and electric potential, the topological corner states are spin polarized with opposite spins localized at different corners, thereby demonstrating a spin-corner state locking mechanism. Transport characteristics, including transmission, local density of states, and local current density, are calculated for a two-terminal setup consisting of a diamond-shaped Kekulé lattice connected to two leads. When opposite local magnetization is applied to the corners, spin-up and spin-down electrons are perfectly separated, forming two spin-polarized conducting channels and leading to spin spatial separation. In the presence of identical local magnetization on both corners and an electric potential at one corner, the spin-polarized corner states can facilitate selective filtering of different spins and generate spin-polarized currents by tuning the energy. Furthermore, spin-resolved transmission diagrams as functions of both the Fermi energy and electric potential are presented, illustrating the global distribution of spin filtering through topological corner states.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phys. Rev. B 110, 125433 (2024)
Large Spin Nernst Effect in Ni70Cu30 Alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Wen-Yuan Li, Chia-Hsi Lin, Guang-Yu Guo, Ssu-Yen Huang, Danru Qu
The interplay among heat, spin, and charge is the central focus in spin caloritronic research. While the longitudinal heat-to-spin conversion via the spin Seebeck effect has been intensively studied, the transverse heat-to-spin conversion via the spin Nernst effect (SNE) has not been equally explored. One major challenge is the minuscule signals generated by the SNE, which are often mixed with the background noises. In this work, we overcome this difficulty by studying the thin films of Ni70Cu30 alloy with not only a sizable spin Hall angle but also a large Seebeck coefficient. We observe in the Ni70Cu30 alloy a large spin Nernst effect with an estimated spin Nernst angle ranging from -28% to -72%. In comparison, the spin Nernst angle for Pt is -8.2%. Our ab initio calculation reveals that the large spin Nernst conductivity in Ni70Cu30 is caused by the Fermi energy shift to the steepest slope of the spin Hall conductivity curve due to electron doping from 30% Cu. Our study provides critical directions in searching for materials with a large spin Nernst effect.
Materials Science (cond-mat.mtrl-sci)
Phys. Rev. B 111, 054421 (2025)
Resolving the Thermal Paradox: Many-body localization or fractionalization?
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Saikat Banerjee, Piers Coleman
Thermal measurements of heat capacity and thermal conductivity in a
wide range of insulators and superconductors exhibit a
thermal paradox": a large linear specific heat reminiscent of neutral Fermi surfaces in samples that exhibit no corresponding linear temperature coefficient to the thermal conductivity. At first sight, these observations appear to support the formation of a continuum of thermally localized many-body excitations, a form of many-body localization that would be fascinating in its own right. Here, by mapping thermal conductivity measurements onto thermal RC circuits, we argue that the development of extremely long thermal relaxation times, athermal
bottleneck," is likely in systems with either many-body localization or
neutral Fermi surfaces due to the large ratio between the electron and
phonon specific heat capacities. We present a re-evaluation of thermal
conductivity measurements in materials exhibiting a thermal paradox that
can be used in future experiments to deliberate between these two
exciting alternatives.
Strongly Correlated Electrons (cond-mat.str-el)
5+3 Pages, 2 Tables, and 1 Figure
General method for calculating transport properties of disordered mesoscopic systems based on the nonequilibrium Green's function formalism
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Gaoyang Li, MiaoMiao Wei, Fuming Xu, Jian Wang
Disorder scattering plays important roles in quantum transport as well as various Hall effects, including the second-order nonlinear Hall effect induced by Berry curvature dipole. Calculation of disorder-averaged transport properties usually requires substantial computational resources, especially for higher-order effects. Existing methods are either limited by approximation conditions or constrained by numerical stability, making it difficult to conveniently obtain average physical quantities over a wide range of disorder strength. In this work, we develop a general method for noninteracting system to obtain analytical expressions of disorder averages in finite orders of disorder strength. This method utilizes the Dyson equation to expand physical quantities expressed in terms of the Green's functions into series of disorder-averaged matrices, and the only approximation involved is the truncation of the Dyson equation. Therefore, this method not only avoids the brute force calculation of disorder samples, but also widely applies to different model systems, types of disorder, and the number of Green's functions in the expressions. We demonstrate the applicability of this general method by calculating averages of the linear conductance of a two-terminal system, the spin Hall conductance and the second-order nonlinear conductance of four-terminal Hall setups. It is found that truncation at the fourth order of disorder strength provides a reasonable accuracy and a convenient Padé treatment effectively extends its applicable range. Numerical results also confirms disorder enhancement of the second-order nonlinear Hall current in four-terminal systems. Moreover, more accurate predictions for a broader range of disorder strength can be achieved by including higher-order terms in a similar manner.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Phys. Rev. B 111, 035409 (2025)
Rigorous lower bound of the dynamical critical exponent of the Ising model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-17 20:00 EST
Rintaro Masaoka, Tomohiro Soejima, Haruki Watanabe
To date, the best known bound of the dynamic critical exponent \(z\) of the \(d\)-dimensional kinetic Ising model is \(z\geq 2-\eta\). We rigorously improve this bound to \(z\geq 2\).
Statistical Mechanics (cond-mat.stat-mech), Other Condensed Matter (cond-mat.other), Mathematical Physics (math-ph), Quantum Physics (quant-ph)
5+6 pages
Evidence of magnetoelastic coupling and magnetic phase coexistence in Mn\(_{1.7}\)Fe\(_{1.3}\)Si Heusler Alloy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Kulbhushan Mishra, Elaine T. Dias, Rajeev Joshi, A. D. Fortes, Christopher M. Howard, Rajeev Rawat, P. A. Bhobe
Noncollinear metallic antiferromagnets, with their rapid spin dynamics, efficient spin transport, and distinctive spin textures, play a pivotal role in advancing the field of spintronics. In this study, we report a comprehensive investigation of the structural, magnetic, and transport properties of cubic Mn\(_{1.7}\)Fe\(_{1.3}\)Si Heusler compound. Temperature-dependent magnetization measurement reveals a paramagnetic to ferromagnetic transition at \(T_C\) = 85 K, followed by a spin reorientation transition. Neutron diffraction data, analyzed as a function of temperature, demonstrates that the occurrence of a spin-reorientation transition is accompanied by magnetoelastic coupling, as evidenced by a change in unit cell volume below \(T_C\). Magnetic structure refinement of the low-temperature neutron powder diffraction data confirms the canted antiferromagnetic ordering below 55 K. The metallic nature of the sample is confirmed by the gradual decrease in the \(\rho\)(T) with decreasing temperature. At low temperatures, a field-induced metamgnetic transition is observed in both, magnetization and magneto-transport measurements. The \(H-T\) phase diagram shows a phase-coexistence region emerging at low temperatures for H \(<\) 2.5 T. These findings provide valuable insights into the magnetic and transport behavior of the Heusler compounds, underscoring their potential for spintronic applications.
Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other)
11 pages, 10 figures
Pressure-Induced Structural and Dielectric Changes in Liquid Water at Room Temperature
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Understanding the pressure-dependent dielectric properties of water is crucial for a wide range of scientific and practical applications. In this study, we employ a deep neural network trained on density functional theory data to investigate the dielectric properties of liquid water at room temperature across a pressure range of 0.1 MPa to 1000 MPa. We observe a nonlinear increase in the static dielectric constant \(\epsilon_0\) with increasing pressure, a trend that is qualitatively consistent with experimental observations. This increase in \(\epsilon_0\) is primarily attributed to the increase in water density under compression, which enhances collective dipole fluctuations within the hydrogen-bonding network as well as the dielectric response. Despite the increase in \(\epsilon_0\), our results reveal a decrease in the Kirkwood correlation factor \(G_K\) with increasing pressure. This decrease in \(G_K\) is attributed to pressure-induced structural distortions in the hydrogen-bonding network, which weaken dipolar correlations by disrupting the ideal tetrahedral arrangement of water molecules.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph)
Quantifying Phase Magnitudes of Open-Source Focused-Probe 4D-STEM Ptychography Reconstructions
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Accurate computational ptychographic phase reconstructions are enabled by fast direct-electron cameras with high dynamic ranges used for four-dimensional scanning transmission electron microscopy (4D-STEM). The availability of open software packages is making such analyses widely accessible, and especially when implemented in Python, easy to compare in terms of computational efficiency and reconstruction quality. In this contribution, I reconstruct atomic phase shifts from convergent-beam electron diffraction maps of pristine monolayer graphene, which is an ideal dose-robust uniform phase object, acquired on a Dectris ARINA detector installed in a Nion UltraSTEM 100 operated at 60 keV with a focused-probe convergence semi-angle of 34 mrad. For two different recorded maximum scattering angle settings, I compare a range of direct and iterative open-source phase reconstruction algorithms, evaluating their computational efficiency and tolerance to reciprocal-space binning and real-space thinning of the data. The quality of the phase images is assessed by quantifying the variation of atomic phase shifts using a robust parameter-based method revealing an overall agreement with some notable differences in the absolute magnitudes and the variation of the phases. Although such variation is not a major issue when analyzing data with many identical atoms, it does put limits on what level of precision can be relied upon for unique sites such as defects or dopants, which also tend to be more dose-sensitive. Overall, these findings and the accompanying open data and code provide useful guidance for the sampling required for desired levels of phase precision, and suggest particular care is required when relying on electron ptychography for quantitative analyses of atomic-scale electromagnetic properties.
Materials Science (cond-mat.mtrl-sci)
17 pages, 8 figures
Removal of excess iron by annealing processes and emergence of bulk superconductivity in sulfur-substituted FeTe
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-17 20:00 EST
Ryosuke Kurihara, Ryusuke Kogure, Tomotaka Ota, Yuto Kinoshita, Satoshi Hakamada, Masashi Tokunaga, Hiroshi Yaguchi
There are several strategies to discover new superconductors. Growing new materials and applying high pressures can be the classic ways since superconductivity was found. Also, chemical processing, such as annealing, is another way to induce superconductivity in a non-superconducting material. Here, we show chemical processing effects in the non-superconducting material, sulfur-substituted FeTe. It has been known that superconductivity in S-substituted FeTe is induced by O\(_2\) annealing. We revealed that hydrochloric acid etching and vacuum annealing for O\(_2\)-annealed samples made the quality of superconductivity higher by several physical property measurements. Furthermore, we visualized the superconducting regions by a magneto-optical imaging technique, indicating that the superconductivity in the processed sample was bulk. In this sample, we confirmed that the concentration of excess iron was reduced compared to that in the as-grown state. These results provide an important route to bulk superconductivity in S-substituted FeTe and its related iron-based compounds.
Superconductivity (cond-mat.supr-con)
Accepted in Phys. Rev. Mater
Fractional-flux oscillations of Josephson critical currents in multi-gap superconductors: a test for unconventional superconductivity
New Submission | Superconductivity (cond-mat.supr-con) | 2025-02-17 20:00 EST
Josephson-junction interferometry has played a pivotal role in uncovering unconventional superconductivity in the cuprates. Using a Ginzburg-Landau-like approach, we generalize previous results to the genuine multi-gap case. Thus, we show that fractional flux oscillations of the Josephson critical current can arise as a direct consequence of multi-gap superconductivity. These oscillations reveal key information about the underlying superconducting states, including the unconventional \(s_\pm\)-wave state. Thus, our findings suggest new phase-sensitive experiments to characterize the Cooper pairing of new emerging superconductors such as the nickelates.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci), Quantum Gases (cond-mat.quant-gas), Strongly Correlated Electrons (cond-mat.str-el)
4 pages, 3 figures
Band Structure Engineering, Optical, Transport, and Photocatalytic Properties of Pristine and Doped Nb3O7(OH): A Systematic DFT Study
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Wilayat Khan, Alishba Tariq, Jan Minar, Sawera Durrani, Abdul Raziq, Sikander Azam, Khalid Saeed
Nb3O2(OH) has emerged as a highly attractive photocatalyst based on its chemical stability, energetic band positions, and large active lattice sites. Compared to other various photocatalytic semiconductors, it can be synthesized easily. This study presents a systematic analysis of pristine and doped Nb3O7(OH) based on recent developments in related research. The current study summarizes the modeling approach and computationally used techniques for doped Nb3O7(OH) based photocatalysts, focusing on their structural properties, defects engineering, and band structure engineering. This study demonstrates that the Trans-Blaha modified Becke Johnson approximation (TB-mBJ) is an effective approach for optoelectronic properties of pristine and Ta/Sb-doped Nb3O7(OH). The generalized gradient approximation is used for structure optimization of all systems studied. Spin-orbit (SO) coupling is also applied to deal with the Ta f orbital and Sb d orbital in the Ta/Sb-doped systems. Doping shifts the energetic band positions and relocates the Fermi level i.e. both the valence band maximum and the conduction band minimum are relocated, decreasing the band gap from 1.7 eV (pristine), to 1.266 eV (Ta-doped)/1.203 eV (Sb-doped). Moreover, doped systems shift the optical threshold to the visible region. Transport properties like effective mass and electrical conductivity are calculated, reflecting that the mobility of charge carriers increases with the doping of Ta/Sb this http URL reduction in the band gap and red-shift in the optical properties of the Ta/Sb-doped Nb3O7(OH) to the visible region suggest their promising potential for photocatalytic activity and photoelectrochemical solar cells.
Materials Science (cond-mat.mtrl-sci)
Final submited version, postprint
RSC Adv., 2025,15, 2452-2460
Universal Machine Learning Interatomic Potentials are Ready for Solid Ion Conductors
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Hongwei Du, Jian Hui, Lanting Zhang, Hong Wang
With the rapid development of energy storage technology, high-performance solid-state electrolytes (SSEs) have become critical for next-generation lithium-ion batteries. These materials require high ionic conductivity, excellent electrochemical stability, and good mechanical properties to meet the demands of electric vehicles and portable electronics. However, traditional methods like density functional theory (DFT) and empirical force fields face challenges such as high computational costs, poor scalability, and limited accuracy across material systems. Universal machine learning interatomic potentials (uMLIPs) offer a promising solution with their efficiency and near-DFT-level this http URL study systematically evaluates six advanced uMLIP models (MatterSim, MACE, SevenNet, CHGNet, M3GNet, and ORBFF) in terms of energy, forces, thermodynamic properties, elastic moduli, and lithium-ion diffusion behavior. The results show that MatterSim outperforms others in nearly all metrics, particularly in complex material systems, demonstrating superior accuracy and physical consistency. Other models exhibit significant deviations due to issues like energy inconsistency or insufficient training data this http URL analysis reveals that MatterSim achieves excellent agreement with reference values in lithium-ion diffusivity calculations, especially at room temperature. Studies on Li3YCl6 and Li6PS5Cl uncover how crystal structure, anion disorder levels, and Na/Li arrangements influence ionic conductivity. Appropriate S/Cl disorder levels and optimized Na/Li arrangements enhance diffusion pathway connectivity, improving overall ionic transport performance.
Materials Science (cond-mat.mtrl-sci), Machine Learning (cs.LG)
Monitoring Vibrational Evolution in Jahn-Teller Effect by Raman Imaging
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Hai-Zhen Yu, Dingwei Chu, Yuanzhi Li, Li Wang, Yuzhi Song, Sai Duan, Chuan-Kui Wang, Zhen Xie
The Jahn-Teller effect (JTE) reduces the geometrical symmetry of a system with degenerate electronic states via vibronic coupling, playing a pivotal role in molecular and condensed systems. In this Letter, we propose that vibrational resolved tip-enhanced Raman scattering images can visualize the vibrational evolutions in JTE in real space. Taking an experimentally viable single zinc phthalocyanine (ZnPc) molecule as a proof-of-principle example, not only the degenerate vibrational splitting but also the overlooked vibration mixing caused by the JTE in its anionic form can be straightforwardly characterized by Raman images. Leveraging Raman images, the controllable configuration of JTE distortion with partial isotopic substitution could be further identified. These findings establish a practical protocol to monitor the detailed vibrational evolutions when a single molecule experiences JTE, opening a door for visualization of spontaneous symmetry breaking in molecular and solid-state systems.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
6 pages, 4 figures
Spontaneous in-plane anomalous Hall response observed in a ferromagnetic oxide
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Shinichi Nishihaya, Yuta Matsuki, Haruto Kaminakamura, Yoshiya Murakami, Hiroaki Ishizuka, Masaki Uchida
Recent observation of anomalous Hall effect (AHE) induced by magnetic field or spin magnetization lying in the Hall deflection plane has sparked interest in diverse mechanisms for inducing the Hall vector component perpendicular to the applied magnetic field. Such off-diagonal coupling, which is strictly constrained by symmetry of the system, provides new degrees of freedom for engineering Hall responses. However, spontaneous response as extensively studied for out-of-plane AHE remains unexplored. Here we elucidate in-plane AHE in a typical ferromagnetic oxide SrRuO\(_3\). The (111)-orientated ultrathin films with in-plane easy axes of spin magnetization exhibit spontaneous AHE at zero field, which is intrinsically coupled to the in-plane spin magnetization and controllable via its direction. Systematic measurements by varying azimuthal and polar field angles further reveal complex Hall responses shaped by higher-order terms allowed by trigonal distortion of the films. Our findings highlight versatile and controllable in-plane Hall responses with out-of-plane orbital ferromagnetism.
Materials Science (cond-mat.mtrl-sci), Strongly Correlated Electrons (cond-mat.str-el)
16 pages, 4 figures
Phases and critical transport of the SU(N) Hofstadter-Hubbard model on the triangular lattice
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Lu Zhang, Rongning Liu, Xue-Yang Song
We study phases and transitions of a triangular Hubbard model subject to commensurate magnetic field, called the Hofstadter-Hubbard model. At filling one fermion per site, for the number of fermion flavors 2 <= N <= 4, we identify three distinct phases and calculate critical interaction strength from self-consistent mean-field approximation. Integer quantum Hall, chiral spin liquid, and valence bond solid (or stripe) states could be realized upon varying the Hubbard interaction U. We study the critical transport behavior using quantum Boltzmann equations for general N for the putative continuous transition from quantum Hall states to chiral spin liquid. The critical behavior serves as strong signatures of the critical theory and consequently of the existence of chiral spin liquid as the proximate phase.
Strongly Correlated Electrons (cond-mat.str-el)
9 pages, 4 figures
Modeling metamaterials by second-order rate-type constitutive relations between only the macroscopic stress and strain
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Vít Průša, K. R. Rajagopal, Casey Rodriguez, Ladislav Trnka, Martin Vejvoda
We propose a thermodynamically based approach for constructing
effective rate-type constitutive relations describing finite
deformations of metamaterials. The effective constitutive relations are
formulated as second-order in time rate-type Eulerian constitutive
relations between only the Cauchy stress tensor, the Hencky strain
tensor and objective time derivatives thereof. In particular, there is
no need to introduce additional quantities or concepts such as
micro-level deformation'',micromorphic continua'', or
elastic solids with frequency dependent material properties. Moreover,
the linearisation of the proposed fully nonlinear (finite deformations)
constitutive relations leads, in Fourier/frequency space, to the same
constitutive relations as those commonly used in theories based on the
concepts of frequency dependent density and/or stiffness. From this
perspective the proposed constitutive relations reproduce the behaviour
predicted by the frequency dependent density and/or stiffness models,
but yet they work with constant -- that is motion independent --
material properties. This is clearly more convenient from the physical
point of view. Furthermore, the linearised version of the proposed
constitutive relations leads to the governing partial differential
equations that are particularly simple both in Fourier space as well as
in physical space. Finally, we argue that the proposed fully nonlinear
(finite deformations) second-order in time rate-type constitutive
relations do not fall into traditional classes of models for elastic
solids (hyperelastic solids/Green elastic solids, first-order in time
hypoelastic solids), and that the proposed constitutive relations embody
a class of constitutive relations characterising elastic solids.
Materials Science (cond-mat.mtrl-sci)
Multifunctional Altermagnet with Large Out-of-Plane Piezoelectric Response in Janus V\(_{2}\)AsBrO Monolayer
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Qiuyue Ma, Busheng Wang, Guochun Yang, Yong Liu
Altermagnetism has emerged as a third fundamental category of collinear magnetism, characterized by spin-splitting in symmetry-compensated collinear antiferromagnets, opening new frontiers in spintronics and condensed matter physics. Here, based on first-principles calculations, we propose a novel altermagnetic semiconductor, the asymmetric Janus V\(_2\)AsBrO monolayer, which exhibits a magnetic easy axis favoring the out-of-plane direction and a Néel temperature (\(T_N\)) exceeding room temperature. The system exhibits a strain-tunable piezovalley effect, generating valley polarization under uniaxial strain. Notably, hole doping under uniaxial strain generates a net magnetization (\(M\)) through a piezomagnetic mechanism. Additionally, the broken inversion symmetry endows the monolayer with a substantial out-of-plane piezoelectric coefficient \(d_{31}\) (2.19 pm/V), presenting broad prospects for the development and design of novel piezoelectric devices. Our findings provide a promising candidate material for the advancement of 2D multifunctional devices in nanoelectronics, spintronics, valleytronics, and piezoelectrics.
Materials Science (cond-mat.mtrl-sci)
17 pages, 4 figures
Transverse vortices induced by modulated granular shear flows of elongated particles
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-17 20:00 EST
Sára Lévay, Philippe Claudin, Ellák Somfai, Tamás Börzsönyi
We have performed DEM simulations of elongated grains in a shear cell for various particle aspect ratios and contact frictions, with an additional heterogeneous force perturbation in the flow direction. For a perturbation in the form of a single Fourier mode, we show that the response of the system consists of transverse secondary flows that average onto a pattern of four vortices. We have also theoretically studied this phenomenon by generalizing the granular rheology \(\mu(I)\) to the case of elongated grains and computing the linear response to such a perturbation. Even if the agreement between theory and simulations remains qualitative only, we can reproduce and understand the inversion of the vortex pattern when the cell aspect ratio is increased from a vertically to a horizontally elongated cell shape, emphasizing the key role of the second normal stress difference as well as the cell geometry.
Soft Condensed Matter (cond-mat.soft), Other Condensed Matter (cond-mat.other)
Balloon regime: Drop elasticity leads to complete rebound
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-17 20:00 EST
D. Díaz, A.G. Balasubramanian, K. Amini, X. Li, F. Lundell, S. Bagheri, O. Tammisola
When a viscoelastic shear-thinning drop of high elasticity hits a superhydrophobic surface, a growing tail-like filament vertically emerges from the impact spot as the contact line recedes. Notably, the ligament transitions into a balloon-like shape before detaching (Balloon regime) completely from the surface. Here, we attribute the ligament formation to the liquid impalement upon impact into the surface protrusion spacing. Our findings reveal that ligament formation can be controlled by tuning the roughness and surface wettability. We show that ligament stretching mainly depends on inertia and gravity, whereas the high elasticity prevents the ligament break up, enabling complete rebounds.
Soft Condensed Matter (cond-mat.soft), Fluid Dynamics (physics.flu-dyn)
4 pages, 4 figures
The speed of sound and elastic properties of single crystals of inorganic and hybrid lead-free iodide perovskites obtained by femtosecond transient optical reflectivity
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Giuseppe Ammirati, Patrick O Keeffe, Stefano Turchini, Daniele Catone, Alessandra Paladini, Francesco Toschi, Stevan Gavranovic, Jan Pospisil, Giovanni Mannino, Salvatore Valastro, Faustino Martelli
Optoelectronic devices operate under continuous thermal stress that may influence both long-term stability and optical properties of the active material. It is therefore useful to know the elastic properties of the active materials. In general, the elastic constants of a material may be deduced by the measurement of the speed of sound in that material. In this work, we report on the measurements of the speed of sound in three lead-free halide perovskites, namely the inorganic Cs3Bi2I9 and the hybrid MA3Bi2I9 and MA3Sb2I9, by means of femtosecond transient optical reflectivity that shows oscillations of the signal intensity that are related to the strain field caused by the photoexcitation of electron-hole pairs. The values of the speed of sound thus obtained have allowed us to extract the elastic constant, c11, along the propagation direction of the light. The c11 values indicate a lower stiffness of the hybrid materials, an important aspect when designing optoelectronic devices.
Materials Science (cond-mat.mtrl-sci)
Softened Spin Waves in Films with Perpendicular Magnetic Anisotropy: Sombrero-Like Dispersion, Negative Reflection, Bi-, and Trireflection
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Nikodem Leśniewski, Yuliya S. Dadoenkova, Florian F. L. Bentivegna, Paweł Gruszecki
We theoretically investigate the effect of perpendicular magnetic anisotropy (PMA) on spin wave (SW) dynamics at low magnetic fields. PMA exerts an in-plane torque on magnetization, counteracting exchange, dipolar, and Zeeman torques, thereby significantly transforming SW dynamics. In ultrathin films, sombrero-like dispersion relation facilitates bireflection and negative reflection of SWs, while in thicker films we demonstrate anti-Larmor precession, cowboy-hat-like dispersion relation, and trireflection of SWs. These results open up new opportunities to explore wave phenomena beyond magnonics.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Boson-Gutzwiller Quantum liquids on a lattice
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-17 20:00 EST
Daniel Pérez-Cruz, Manuel Valiente
We consider one-dimensional, interacting spinless bosons on a tight-binding lattice described by the Bose-Hubbard model. Besides attractive on-site two-body interactions, we include a three-body repulsive term such that the competition between these two forces allows the formation of self-bound liquid states. We investigate the properties of this system using the Gutzwiller approximation, showing that, indeed, this mean-field approach also supports liquid states. We find that for densities lower than the equilibrium density, the Gutzwiller method, and other mean-field approaches -- such as the Gross-Pitaevskii theory -- feature a sharp transition to the vacuum state. This, however, is avoided by considering local minima of the functional in the standard manner. We also study the excitation spectrum, and calculate the speed of sound, in full agreement with the usual expression obtained from the thermodynamic equation of state. We study their corresponding quantum droplets variationally and find that the results behave in accordance with the one-dimensional liquid drop model.
Quantum Gases (cond-mat.quant-gas)
8 pages, 7 figures
Microwave pulse transparency in Flux-qubit based superconducting quantum metamaterial
New Submission | Other Condensed Matter (cond-mat.other) | 2025-02-17 20:00 EST
S. Galovic, Z. Ivic, V. Nikolic, Z. Przulj, D. Chevizovich
We consider the propagation of a classical microwave pulse through a simple setup of a quantum metamaterial composed of a large number of three-Josephson-junction flux qubits. We find that population inversion and electromagnetic waves propagate together as two-component nonlinear waves, exhibiting distinct features depending on the initial preparation of the qubit subsystem and the strength of the "matter"-light interaction. Three different regimes are observed. In the limit of weak nonlinearity, when all qubits are initially prepared in either the clockwise or counterclockwise persistent current state, population inversion undergoes coherent Rabi-like oscillations, with a complete transfer between these two opposite states. As nonlinearity approaches unity, the transition dynamics lose their oscillatory nature, and the system rapidly becomes frozen in a state of zero population inversion, where each qubit is trapped in a superposition with equal probabilities of clockwise and counterclockwise polarity. In the overcritical regime, population inversion exhibits pulsating behavior, but without complete transfer. In the extreme coupling limit, population inversion undergoes small-amplitude oscillations around its initial value, while the pulse amplitude oscillates around zero, indicating pulse stopping.
Other Condensed Matter (cond-mat.other)
Energy diffusion in the long-range interacting spin systems
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-17 20:00 EST
Hideaki Nishikawa, Keiji Saito
We investigate energy diffusion in long-range interacting spin systems, where the interaction decays algebraically as \(V(r) \propto r^{-\alpha}\) with the distance \(r\) between the sites. We consider prototypical spin systems, the transverse Ising model, and the XYZ model in the \(D\)-dimensional lattice with finite \(\alpha >D\) which guarantees the thermodynamic extensivity. In one dimension, both normal and anomalous diffusion are observed, where the anomalous diffusion is attributed to anomalous enhancement of the amplitude of the equilibrium current correlation. We prove the power-law clustering property of arbitrary orders of joint cumulants in general dimensions. Applying this theorem to equal-time current correlations, we further prove several theorems leading to the statement that the sufficient condition for normal diffusion in one dimension is \(\alpha > 3/2\) regardless of the models. The fluctuating hydrodynamics approach consistently explains Lévy diffusion for \(\alpha < 3/2\), which implies the condition is optimal. In higher dimensions of \(D \geq 2\), normal diffusion is indicated as long as \(\alpha > D\). Pecular behavior for \(\alpha <D\) is also discussed.
Statistical Mechanics (cond-mat.stat-mech), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
7 + 34 pages, 4 + 26 figures
Single-molecule phosphorescence and intersystem crossing in a coupled exciton-plasmon system
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Abhishek Grewal, Hiroshi Imada, Kuniyuki Miwa, Miyabi Imai-Imada, Kensuke Kimura, Rafael Jaculbia, Klaus Kuhnke, Klaus Kern, Yousoo Kim
Scanning the sharp metal tip of a scanning tunneling microscope (STM) over a molecule allows tuning the coupling between the tip plasmon and a molecular fluorescence emitter. This allows access to local variations of fluorescence field enhancement and wavelength shifts, which are central parameters for characterizing the plasmon-exciton coupling. Performing the same for phosphorescence with molecular scale resolution remains a significant challenge. In this study, we present the first investigation of phosphorescence from isolated Pt-Phthalocyanine molecules by analyzing tip-enhanced emission spectra in both current-induced and laser-induced phosphorescence. The latter directly monitors singlet-to-triplet state intersystem crossing of a molecule below the tip. The study paves the way to a detailed understanding of triplet excitation pathways and their potential control at sub-molecular length scales. Additionally, the coupling of organic phosphors to plasmonic structures is a promising route for the improving light-emitting diodes.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
39 pages, 12 figures
Light-induced dissipationless states in magnetic topological insulators with hexagonal warping
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Mohammad Shafiei, Milorad V. Milošević
Magnetic impurities in topological insulators (TIs) induce backscattering via magnetic torque, unlike pristine TIs where spin-orbit locking promotes dissipationless surface states. Here we reveal that one can suppress that unwanted backscattering and dissipation in magnetic TIs using high-frequency linearly polarized light (LPL). By carefully considering the hexagonal warping of the Fermi surface of the TI, we demonstrate how the coupling between Dirac surface states and LPL can effectively reduce backscattering on magnetic dopants, enhance carrier mobility and suppress resistance, even entirely. These findings open up avenues for designing ultra low-power sensing and spintronic technology.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Panoscopic non-equilibrium fluctuation identity
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-17 20:00 EST
Juliana Caspers, Karthika Krishna Kumar, Clemens Bechinger, Matthias Krüger
Quantifying and characterizing fluctuations far away from equilibrium is a challenging task. We introduce and experimentally confirm an identity for a driven classical system, relating the different non-equilibrium cumulants of the observable conjugate to the driving protocol. The identity is valid from micro- to macroscopic length scales, and it encompasses the fluctuation dissipation theorem. We apply it in experiments of a Brownian probe particle confined and driven by an optical potential and suspended in a nonlinear and non-Markovian fluid.
Statistical Mechanics (cond-mat.stat-mech), Soft Condensed Matter (cond-mat.soft)
5 pages, 4 figures
Identities for nonlinear memory kernels
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-02-17 20:00 EST
Juliana Caspers, Matthias Krüger
Perturbing a system far away from equilibrium via a time dependent protocol can formally be described by a nonlinear Volterra series expansion. Here we derive identities for the nonlinear memory kernels arising in such nonlinear expansion, including the possibility of a nonlinear coupling between perturbation and system. These identities rely on local detailed balance, and they include the fluctuation dissipation theorem as the lowest order identity. We test them in simulations for driven over- and underdamped Brownian particles. These identities for memory kernels can be recast in a series relation for the non-equilibrium cumulants of the observable conjugate to the driving and the observable described by the Volterra series.
Statistical Mechanics (cond-mat.stat-mech)
11 pages, 5 figures
THz electric field control of spins in collinear antiferromagnet Cr\(_{2}\)O\(_{3}\)
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
V. R. Bilyk, R. M. Dubrovin, A. K. Zvezdin, A. I. Kirilyuk, A. V. Kimel
The idea to find a magnet that responds to an electric field as efficiently as to its magnetic counterpart has long intrigued people's minds and recently became a cornerstone for future energy efficient and nano-scalable technologies for magnetic writing and information processing. In contrast to electric currents, a control by electric fields promises much lower dissipations and in contrast to magnetic fields, electric fields are easier to apply to a nanoscale bit. Recently, the idea to find materials and mechanisms facilitating a strong and simultaneously fast response of spins to electric field has fueled an intense research interest to electromagnons in non-collinear antiferromagnets. Here we show that THz spin resonance at the frequency 0.165 THz in collinear antiferromagnet Cr\(_{2}\)O\(_{3}\), which does not host any electromagnons, can be excited by both THz magnetic and electric fields. The mechanisms result in comparable effects on spin dynamics, when excited by freely propagating electromagnetic wave, but have different dependencies on the orientation of the applied THz electric field and the antiferromagnetic Néel vector. Hence this discovery opens up new chapters in the research areas targeting to reveal novel principles for the fastest and energy efficient information processing - ultrafast magnetism, antiferromagnetic spintronics, and THz magnonics.
Materials Science (cond-mat.mtrl-sci)
High-accuracy evaluation of non-thermal magnetic states beyond spin-wave theory: applications to higher-energy states
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Wesley Roberts, Michael Vogl, Roderich Moessner, Gregory A. Fiete
We present an approximation scheme based on selective Hilbert space truncation for characterizing non-thermal states of magnetic systems beyond spin-wave theory. We study applications to states that are inaccessible through linear spin-wave theory, such as multi-magnon states and higher-energy states. Our approach is based on the existence of an exact representation of spin operators in terms of finite-order polynomials of bosonic operators. It can be applied to systems with and without a magnetically ordered ground state. The approximation exactly diagonalizes the bosonic Hamiltonian restricted to particular boson occupation subspaces, improving the conventional linear spin-wave approach and exponentially reducing the computing time relative to exact diagonalization schemes. As a test case, we apply the approach to a prototypical one-dimensional model - an XXZ spin chain with an applied magnetic field and antisymmetric exchange coupling. Here the antisymmetric coupling introduces a continuous parameter to tune the system away from its exactly solvable limit. We find excellent agreement between numerically exact eigenstates and eigenvalues and those found via the approximation scheme. Our approach applies not just to higher lying states but also to boson bound states, which could make them more accessible to theoretical predictions for comparison with experiment.
Strongly Correlated Electrons (cond-mat.str-el)
Low-Defect Quantum Dot Lasers Directly Grown on Silicon Exhibiting Low Threshold Current and High Output Power at Elevated Temperatures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-02-17 20:00 EST
Konstantinos Papatryfonos, Jean-Christophe Girard, Mingchu Tang, Huiwen Deng, Alwyn J. Seeds, Christophe David, Guillemin Rodary, Huiyun Liu, David R. Selviah
The direct growth of III-V materials on silicon is a key enabler for developing monolithically integrated lasers, offering substantial potential for ultra-dense photonic integration in vital communications and computing technologies. However, the III-V/Si lattice and thermal expansion mismatch pose significant hurdles, leading to defects that degrade lasing performance. This study overcomes this challenge, demonstrating InAs/GaAs-on-Si lasers that perform on par with top-tier lasers on native GaAs substrates. This is achieved through a newly developed epitaxial approach comprising a series of rigorously optimised growth strategies. Atomic-resolution scanning tunnelling microscopy and spectroscopy experiments reveal exceptional material quality in the active region, and elucidate the impact of each growth strategy on defect dynamics. The optimised III-V-on-silicon ridge-waveguide lasers demonstrate a continuous-wave threshold current as low as 6 mA and high-temperature operation reaching 165 °C. At 80 °C, critical for data centre applications, they maintain a 12-mA threshold and 35 mW output power. Furthermore, lasers fabricated on both Si and GaAs substrates using identical processes exhibit virtually identical average threshold current. By eliminating the performance limitations associated with the GaAs/Si mismatch, this study paves the way for robust and high-density integration of a broad spectrum of critical III-V photonic technologies into the silicon ecosystem.
Materials Science (cond-mat.mtrl-sci)
Adv. Photonics Res. 2400082, 2024
Superballistic paradox in electron fluids: Evidence of tomographic transport
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-02-17 20:00 EST
Jorge Estrada-Álvarez, Elena Díaz, Francisco Domínguez-Adame
Electron hydrodynamics encompasses the exotic fluid-like behavior of electrons in two-dimensional materials such as graphene. It accounts for superballistic conduction, also known as the Gurzhi effect, where increasing temperature reduces the electrical resistance. In analogy with conventional fluids, the Gurzhi effect is only expected in the hydrodynamic regime, with the decrease in the resistance occurring at intermediate temperatures. Nonetheless, experiments on electron fluids consistently show that superballistic conduction starts at close-to-zero temperatures. To address this paradox, we study hydrodynamic flow, and we find that replacing the classical dynamics with tomographic dynamics, where only head-on collisions are allowed between electrons, solves the dilemma. The latter strengthens superballistic conduction, with potential applications in low-dissipation devices, and explains its differences with the Molenkamp effect and conventional fluids dynamics. Our study reveals that the superballistic paradox is resolved by considering the electrons not as classical particles but as fermions.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Gases (cond-mat.quant-gas), Statistical Mechanics (cond-mat.stat-mech)
Giant vortex in a harmonically-trapped rotating dipolar \(^{164}\)Dy condensate
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-02-17 20:00 EST
Luis E. Young-S., S. K. Adhikari
We demonstrate the formation of dynamically stable giant vortices in a harmonically-trapped strongly dipolar \(^{164}\)Dy Bose-Einstein condensate under rotation around the polarization direction of dipolar atoms, employing the numerical solution of an improved mean-field model including a Lee-Huang-Yang-type interaction, meant to stop a collapse at high atom density. These giant vortices are stationary, obtainable by imaginary-time propagation using a Gaussian initial state, while the appropriate phase of the giant vortex is imprinted on the initial wave function. The dynamical stability of the giant vortices is established by real-time propagation during a long interval of time after a small change of a parameter.
Quantum Gases (cond-mat.quant-gas)
Variationally optimizing infinite projected entangled-pair states at large bond dimensions: A split-CTMRG approach
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Jan Naumann, Erik Lennart Weerda, Jens Eisert, Matteo Rizzi, Philipp Schmoll
Projected entangled-pair states (PEPS) have become a powerful tool for studying quantum many-body systems in the condensed matter and quantum materials context, particularly with advances in variational energy optimization methods. A key challenge within this framework is the computational cost associated with the contraction of the two-dimensional lattice, crucial for calculating state vector norms and expectation values. The conventional approach, using the corner transfer matrix renormalization group (CTMRG), involves combining two tensor network layers, resulting in significant time and memory demands. In this work, we introduce an alternative "split-CTMRG" algorithm, which maintains separate PEPS layers and leverages new environment tensors, reducing computational complexity while preserving accuracy. Benchmarks on quantum lattice models demonstrate substantial speedups for variational energy optimization, rendering this method valuable for large-scale PEPS simulations.
Strongly Correlated Electrons (cond-mat.str-el), Computational Physics (physics.comp-ph), Quantum Physics (quant-ph)
Electromagnon signatures of a metastable multiferroic state
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Blake S. Dastrup, Zhuquan Zhang, Peter R. Miedaner, Yu-Che Chien, Young Sun, Yan Wu, Huibo Cao, Edoardo Baldini, Keith A. Nelson
Magnetoelectric multiferroic materials, particularly type-II multiferroics where ferroelectric polarizations arise from magnetic order, offer significant potential for the simultaneous control of magnetic and electric properties. However, it remains an open question as to how the multiferroic ground states are stabilized on the free-energy landscape in the presence of intricate competition between the magnetoelectric coupling and thermal fluctuations. In this work, by using terahertz time-domain spectroscopy in combination with an applied magnetic field, photoexcitation, and single-shot detection, we reveal the spectroscopic signatures of a magnetic-field-induced metastable multiferroic state in a hexaferrite. This state remains robust until thermal influences cause the sample to revert to the original paraelectric state. Our findings shed light on the emergence of metastable multiferroicity and its interplay with thermal dynamics.
Strongly Correlated Electrons (cond-mat.str-el)
Impurity-induced moment freezing in NaFe\(_x\)Ru\(_{1-x}\)O\(_2\)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Alon Hendler Avidor, Brenden R. Ortiz, Paul M. Sarte, Qiang Zhang, Stephen D. Wilson
We report the impact of magnetic impurity substitution on the quantum disordered magnetic ground state of NaRuO\(_2\). Local \(S=5/2\) moments are introduced into the frustrated triangular lattice of \(J_{eff}=1/2\) Ru moments via Fe-substitution in NaFe\(_x\)Ru\(_{1-x}\)O\(_2\), and the evolution of the magnetic ground state is reported. Local spin freezing associated with conventional spin glass behavior is observed upon Fe substitution, marking an impurity-induced freezing of the primarily dynamic magnetic ground state in NaRuO\(_2\). Furthermore, local Fe moments induce a Curie-Weiss magnetic behavior in the uniform magnetic susceptibility, and the local moment magnitude is best described by dynamic Ru moments polarized about impurity sites. Our results establish an impurity-doping phenomenology consistent with inherently dynamic moments in NaRuO\(_2\) that are pinned by local magnetic impurities, similar to ``swiss cheese" models of impurity-substituted copper oxides.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures, 2 tables
Phys. Rev. Materials 9, 024404 (2025)
Stretching theory of Hookean metashells
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-02-17 20:00 EST
Despite being governed by the familiar laws of Hookean mechanics, elastic shells patterned with an internal structure (i.e. metashells) exhibit a wealth of unusual mechanical properties with no counterparts in unstructured materials. Here I show that much of this behavior can be captured by a real-valued analog of the inhomogeneous Schrödinger equation, with the lateral pressure experienced by the internal structure in the role of the wave function. In the fine structure limit \(-\) i.e. when the length scale associated with the internal structure is much smaller than the local radius of curvature \(-\) this approach reveals the existence of localized states, in which elastic deformations are prevented to diffuse away from their origin, thereby allowing the internal structure to smoothly adapt to the intrinsic geometry of the metashell. Leveraging on an analogy with scattering states in nearly free electrons, I further show that periodic metashells, obtained from the repetition of the same structural unit periodically in space, support elastic Bloch waves, corresponding to stationary periodic configurations of the internal structure and characterized by a geometry-dependent band structure. When applied to crystalline monolayers, this approach provides a generalization of the elastic theory of interacting topological defect to compressible systems.
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph)
8 pages, 3 figures
Gapping the spin-nodal planes of an anisotropic p-wave magnet to induce a large anomalous Hall effect
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-02-17 20:00 EST
Rinsuke Yamada, Max T. Birch, Priya R. Baral, Shun Okumura, Ryota Nakano, Shang Gao, Yuki Ishihara, Kamil K. Kolincio, Ilya Belopolski, Hajime Sagayama, Hironori Nakao, Kazuki Ohishi, Taro Nakajima, Yoshinori Tokura, Taka-hisa Arima, Yukitoshi Motome, Moritz M. Hirschmann, Max Hirschberger
Antiferromagnets with spin splitting in the electronic structure are desired for novel spintronic phenomena in materials with nearly zero net magnetization. One of the simplest spin-split antiferromagnetic states, the \(p\)-wave magnet, is proposed as a result of collective instability of electron gases. Following a more recent theoretical proposal without strong electron correlations, we here report a material with the symmetry constraints for \(p\)-wave magnetism of conduction electrons in momentum space, based on a texture of magnetic moments in direct space. Our resonant X-ray scattering reveals coplanar, lattice-locked antiferromagnetism that satisfies the required conditions for a \(p\)-wave magnet: it breaks space inversion, but preserves time-reversal (\(T\)) symmetry up to a positional shift in direct space. Consistent with theoretical predictions, the electric conductivity is characteristically anisotropic in this \(p\)-wave magnet. In conducting magnets, the coupling of magnetic spins and freely moving electrons favors small distortions of the \(p\)-wave state, slightly breaking the \(T\) symmetry and inducing a tiny net magnetization. In our material, this gentle symmetry breaking induces an anomalous Hall effect (AHE) with a giant anomalous Hall conductivity for a bulk antiferromagnet, \(\sigma_{xy}>600\,\)S/cm (Hall angle \(>3\,\%\)). The \(p\)-wave magnet has characteristic spin-nodal planes, and such a giant AHE can be attributed to hybridization of electron bands around these nodal regions due to \(T\) breaking.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Other Condensed Matter (cond-mat.other), Applied Physics (physics.app-ph)
10 pages, 4 figures