CMP Journal 2025-05-12
Statistics
Nature Materials: 2
Nature Reviews Physics: 2
arXiv: 65
Nature Materials
Viscous dissipation in the rupture of cell-cell contacts
Original Paper | Biophysical methods | 2025-05-11 20:00 EDT
Aditya Arora, Mohd Suhail Rizvi, Gianluca Grenci, Florian Dilasser, Chaoyu Fu, Modhura Ganguly, Sree Vaishnavi, Kathirvel Paramsivam, Srikanth Budnar, Ivar Noordstra, Alpha S. Yap, Virgile Viasnoff
Cell-cell adhesions mediated by adherens junctions, structures connecting cells to each other and to the cortical cytoskeleton, are essential for epithelial physical and biological integrity. Nonetheless, how such structures resist mechanical stimuli that prompt cell-cell rupture is still not fully understood. Here we challenge the conventional views on cell-cell adhesion stability, highlighting the importance of viscous dissipation at the cellular level. Using microdevices to measure the rupture energy of cell-cell junctions and synthetic cadherins to discriminate cadherin binding energy from downstream cytoskeletal regulation, we demonstrate that the balance between cortical tension and cell shape recovery time determines a transition from ductile to brittle fracture in cell-cell contact. These findings suggest that junction toughness, defined as the junction disruption energy, is a more accurate measure of junctional stability, challenging the current emphasis on bond energy and tension. Overall, our results highlight the role and the regulation of energy dissipation through the cytoskeleton during junction deformation for epithelial integrity.
Biophysical methods, Biophysics, Cell biology
Visualizing subatomic orbital and spin moments using a scanning transmission electron microscope
Original Paper | Ferromagnetism | 2025-05-11 20:00 EDT
Hasan Ali, Jan Rusz, Daniel E. Bürgler, Joseph V. Vas, Lei Jin, Roman Adam, Claus M. Schneider, Rafal E. Dunin-Borkowski
Magnetism originates from the spin and orbital angular momenta of electrons and their coupling. These interactions occur at subatomic scales and a comprehensive understanding of such phenomena relies on characterization techniques capable of probing the spin and orbital moments at atomic resolution. Although electron energy loss magnetic chiral dichroism has previously enabled the detection of magnetic moments at atomic scales, it was limited to a chromatic-aberration-corrected transmission electron microscope. Although possible, the detection of atomic-scale electron energy loss magnetic chiral dichroism in a scanning transmission electron microscope remains elusive due to challenges associated with convergent beam setups. Here we demonstrate the detection of atomic-scale electron energy loss magnetic chiral dichroism signals in a probe-corrected scanning transmission electron microscope. We not only determine the orbital-to-spin moments ratio for individual atomic planes of an iron crystal but also reveal its local variations at subatomic scales. These findings open the possibility of resolving magnetism down to the orbital level in future studies.
Ferromagnetism, Magnetic properties and materials, Microscopy
Nature Reviews Physics
Programmable metasurfaces for future photonic artificial intelligence
Review Paper | Applied optics | 2025-05-11 20:00 EDT
Loubnan Abou-Hamdan, Emil Marinov, Peter Wiecha, Philipp del Hougne, Tianyu Wang, Patrice Genevet
Photonic neural networks (PNNs), which share the inherent benefits of photonic systems, such as high parallelism and low power consumption, could challenge traditional digital neural networks in terms of energy efficiency, latency and throughput. However, producing scalable photonic artificial intelligence (AI) solutions remains challenging. To make photonic AI models viable, the scalability problem needs to be solved. Large optical AI models implemented on PNNs are only commercially feasible if the advantages of optical computation outweigh the cost of their input-output overhead. In this Perspective, we discuss how field-programmable metasurface technology may become a key hardware ingredient in achieving scalable photonic AI accelerators and how it can compete with current digital electronic technologies. Programmability or reconfigurability is a pivotal component for PNN hardware, enabling in situ training and accommodating non-stationary use cases that require fine-tuning or transfer learning. Co-integration with electronics, 3D stacking and large-scale manufacturing of metasurfaces would significantly improve PNN scalability and functionalities. Programmable metasurfaces could address some of the current challenges that PNNs face and enable next-generation photonic AI technology.
Applied optics, Computational science, Nanoscale devices, Photonic devices, Sub-wavelength optics
Neutrinos from explosive transients at the dawn of multi-messenger astronomy
Review Paper | High-energy astrophysics | 2025-05-11 20:00 EDT
Irene Tamborra
With the advent of time-domain astronomy and the game-changing next generation of telescopes, we have unprecedented opportunities to explore the most energetic events in our Universe through electromagnetic radiation, gravitational waves and neutrinos. These are elementary particles, which exist in three different flavours and change the latter as they propagate in the dense core of astrophysical sources as well as en route to Earth. To capitalize on existing and upcoming multi-messenger opportunities, it is crucial to understand: (1) the role of neutrinos in explosive transient sources as well as in the synthesis of the elements heavier than iron; (2) the impact of neutrino physics on the multi-messenger observables and (3) the information on the source physics carried by the detectable neutrino signal. In this Review, the status of this exciting and fast-moving field is outlined, focusing on astrophysical sources linked to collapsing massive stars and neutron-star mergers. In the light of the upcoming plethora of multi-messenger data, outstanding open issues concerning the optimization of multi-messenger detection strategies are discussed.
High-energy astrophysics, Particle astrophysics, Transient astrophysical phenomena
arXiv
Sucrose ester surfactants: current understanding and emerging perspectives
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Diana Cholakova, Slavka Tcholakova
Sucrose esters (SEs), derived from sucrose and fatty acids, are biodegradable and non-toxic surfactants increasingly favored as substitutes for petrochemically-synthesized ones in food, cosmetics, and pharmaceuticals. SEs provide versatile hydrophilic-lipophilic properties, determined by the degree of sucrose esterification ranging from one to eight. The length of the fatty acid residues further influences the phase behavior of SEs, allowing creation of tailored formulations for specific applications. This review provides insights about our current understanding of the SEs phase behavior, their aggregation in aqueous and oily solutions, and its correlation with formulation outcomes. Furthermore, an overview of recent studies investigating SEs in various colloidal systems, incl. emulsions, foams, oleogels, and others, is provided. Novel concepts are discussed alongside future research directions, emphasizing the SEs potential as sustainable, functional ingredients.
Soft Condensed Matter (cond-mat.soft)
Curr. Opin. Colloid Interface Sci. 2024, 73, 101832
Optimizing superlattice bilayer graphene for a fractional Chern insulator
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Dathan Ault-McCoy, M. Nabil Y. Lhachemi, Aaron Dunbrack, Sayed Ali Akbar Ghorashi, Jennifer Cano
Bernal-stacked bilayer graphene modulated by a superlattice potential is a highly tunable system predicted to realize isolated topological flat bands. In this work we calculate the band structure and quantum geometry of bilayer graphene subject to both triangular and square superlattices, across a wide range of gate voltages. We identify the parameter regime that optimizes the “single-particle indicators” for the stability of a fractional Chern insulator (FCI) when a topological flat band is partially filled. Our results guide the experimental realization of an FCI in this platform.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
9 pages, 11 figures
Observation of excitons bound by antiferromagnetic correlations
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
Omar Mehio, Yuchen Han, Xinwei Li, Honglie Ning, Zach Porter, Stephen D. Wilson, David Hsieh
Two-dimensional Mott insulators host antiferromagnetic (AFM) correlations that are predicted to enhance the attractive interaction between empty (holons) and doubly occupied (doublons) sites, creating a novel pathway for exciton formation. However, experimental confirmation of this spin-mediated binding mechanism remains elusive. Leveraging the distinct magnetic critical properties of the Mott antiferromagnets Sr$ _2$ IrO$ _4$ and Sr$ _3$ Ir$ _2$ O$ _7$ , we show using time-resolved THz spectroscopy that excitons only exist at temperatures below where short-range AFM correlation develops. The excitons remain stable up to photodoping densities approaching the predicted excitonic Mott insulator-to-metal transition, revealing a unique robustness against screening. Our results establish the viability of spin-bound excitons and introduce opportunities for excitonic control through magnetic degrees of freedom.
Strongly Correlated Electrons (cond-mat.str-el)
14 pages main text, 4 figures, 16 pages supplementary information
Phys. Rev. Research 7, 013114 (2025)
A Hubbard exciton fluid in a photo-doped antiferromagnetic Mott insulator
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
Omar Mehio, Xinwei Li, Honglie Ning, Zala Lenarčič, Yuchen Han, Michael Buchhold, Zach Porter, Nicholas J. Laurita, Stephen D. Wilson, David Hsieh
The undoped antiferromagnetic Mott insulator naturally has one charge carrier per lattice site. When it is doped with additional carriers, they are unstable to spin fluctuation-mediated Cooper pairing as well as other unconventional types of charge, spin, and orbital current ordering. Photo-excitation can produce charge carriers in the form of empty (holons) and doubly occupied (doublons) sites that may also exhibit charge instabilities. There is evidence that antiferromagnetic correlations enhance attractive interactions between holons and doublons, which can then form bound pairs known as Hubbard excitons, and that these might self-organize into an insulating Hubbard exciton fluid. However, this out-of-equilibrium phenomenon has not been detected experimentally. Here, we report the transient formation of a Hubbard exciton fluid in the antiferromagnetic Mott insulator Sr$ _{2}$ IrO$ _{4}$ using ultrafast terahertz conductivity. Following photo-excitation, we observe rapid spectral weight transfer from a Drude metallic response to an insulating response. The latter is characterized by a finite energy peak originating from intra-excitonic transitions, whose assignment is corroborated by our numerical simulations of an extended Hubbard model. The lifetime of the peak is short, approximately one picosecond, and scales exponentially with Mott gap size, implying extremely strong coupling to magnon modes.
Strongly Correlated Electrons (cond-mat.str-el)
23 pages main text, 4 figures, 4 extended figures, 19 pages supplementary information
Nature Physics 19, 1876-1882 (2023)
Proposal for many-body quantum chaos detection with single-site measurements
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
Isaías Vallejo-Fabila, Adway Kumar Das, Sayan Choudhury, Lea F. Santos
We demonstrate that the long-time dynamics of an observable associated with a single lattice site is sufficient to determine whether a many-body quantum system exhibits level statistics characteristic of random matrix theory, a widely used diagnostic of quantum chaos. In particular, we focus on the partial survival probability and spin autocorrelation function at a single site, both evolved under a disordered spin-1/2 chain, which is a setup realizable in current experimental platforms. Given the precision and timescales currently achievable, our results indicate that the detection of many-body quantum chaos is feasible, but constrained to small system sizes.
Statistical Mechanics (cond-mat.stat-mech)
8 pages, 6 figures
Interpolating between pair-potential systems
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Lorenzo Costigliola, Andreas C. Martine, Claudia X. Romero, Jone E. Steinhoff, Francisco M. F. A. S. da Fonseca, Maria B. T. Nielsen, Jeppe C. Dyre
This paper studies liquid-model systems with almost identical constant-potential-energy hypersurfaces. We simulated continuous interpolations between such systems, specifically between the Lennard-Jones (LJ), Weeks-Chandler-Andersen (WCA), exponent 12 inverse-power-law (IPL), and Yukawa (YK) pair-potential systems. Structure and dynamics were monitored via the radial distribution function and the time-dependent mean-square displacement, respectively. In terms of the interpolation parameter lambda, we argue that two systems have very similar constant-potential-energy hypersurfaces if the potential energies of configurations rarely cross when plotted as functions of lambda. Such absence of “level crossing” applies to a very good approximation for the LJ to WCA transformation, and it also applies to a quite good approximation for the LJ to IPL and the YK to YK transformations (the latter varies the screening length). In all cases, structure and dynamics are shown to be almost invariant as functions of lambda. The density is kept constant when lambda is varied. Temperature must be generally adjusted with lambda, which is done by an iterative “reduced-force-matching” method with no free parameters. We also apply the interpolation strategy to two versions of the Kob-Andersen (KA) binary LJ system and show that a recently introduced shifted-force-cutoff version of this system has constant-potential-energy hypersurfaces, which are almost identical to those of the original KA system. This result rationalizes the previously established fact that the two KA versions have virtually identical physics.
Soft Condensed Matter (cond-mat.soft)
Trends in Gibbs States for Thermodynamics of Canonical Nonlinearity
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
When we consider canonical average for classical discrete systems under constant composition (specifically, substitutional alloys) as a map phi from a set of many-body interatomic interactions to that of microscopic configuration in thermodynamic equilibrium, phi generally exhibits complicated nonlinearity. The nonlinearity has recently been amply studied in terms of configurational geometry, measured by vector field and Kullback-Leibler divergence, whose individual concepts are further unified through stochastic thermodynamic transformation: We call this procedure as Themodynamics of canonical nonlinearity (TCN). Although TCN can reveal the non-linear character across multiple configurations through thermodynamic functions, the essential role for Gibbs states (GBS) in terms of the nonlinearity is still totally unclear. We here tackle this problem, and reveal the characteristic roles of the GBS: (i) Concrete expression of the GBS is derived, (ii) strong correlation between GBSs and averaged nonlinearity over configurations for moled systems is found, and (iii) GBS-based bounds for averaged nonlinearity at specific conditions is derived.
Statistical Mechanics (cond-mat.stat-mech)
5 pages, 1 figure
Subdiffusion of sticky dendrimers in an associative polymer network
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Silpa Mariya, Jeremy J. Barr, P. Sunthar, J. Ravi Prakash
We investigate the static and dynamic properties of dendrimers diffusing through a network of linear associative polymers using coarse-grained Brownian dynamics simulations. Both dendrimers and network chains are modelled as bead-spring chain polymers, with hydrodynamic interactions incorporated for the accurate prediction of dynamic properties. Linear chains form a network via the associating groups distributed along their backbones, and the dendrimers interact attractively or repulsively with the network, enabling a direct comparison of sticky and non-sticky behaviour of dendrimers. Structural analysis reveals that while non-sticky dendrimers shrink with increasing network concentration, similar to linear polymer behaviour, sticky dendrimers exhibit stretching at low concentrations due to binding interactions. Dendrimer dynamics are largely insensitive to network architecture but are strongly influenced by the strength of dendrimer-network interactions. Increasing attraction to the network leads to subdiffusive motion and non-Gaussian displacement statistics, even when dendrimers are smaller than the average mesh size. The long-time diffusivity aligns with theoretical predictions for nanoparticle transport in polymer networks. Additionally, dendrimers deform the network locally, altering the mesh size distribution depending on their stickiness. These findings offer insight into the interplay between macromolecular architecture, binding interactions, and transport in polymeric environments.
Soft Condensed Matter (cond-mat.soft)
18 pages 15 figures, submitted to Macromolecules
Cerium doped graphene-based materials towards oxygen reduction reaction catalysis
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Lanna E.B. Lucchetti, Pedro A.S. Autreto, Mauro C. Santos, James M. de Almeida
With the global transition towards cleaner energy and sustainable processes, the demand for efficient catalysts, especially for the oxygen reduction reaction, has gained attention from the scientific community. This research work investigates cerium-doped graphene-based materials as catalysts for this process with density functional theory calculations. The electrochemical performance of Ce-doped graphene was assessed within the computation hydrogen electrode framework. Our findings reveal that Ce doping, especially when synergized with an oxygen atom, shows improved catalytic activity and selectivity. For instance, Ce doping in combination with an oxygen atom, located near a border, can be selective for the 2-electron pathway. Overall, the combination of Ce doping with structural defects and oxygenated functions lowers the reaction free energies for the oxygen reduction compared to pure graphene, and consequently, might improve the catalytic activity. This research sheds light from a computational perspective on Ce-doped carbon materials as a sustainable alternative to traditional costly metal-based catalysts, offering promising prospects for green energy technologies and electrochemical applications.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Static and dynamic theory of polarization under internal and directing electric fields: Fixed-charge and fixed-potential conditions
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
We present a continuum theory on statics and dynamics of polar fluids, where the orientational polarization $ {\bi p}_1$ and the induced polarization $ {\bi p}_2$ are governed by
the Onsager directing field $ {\bi E}_d$ and the Lorentz internal field $ \bi F$ , respectively. We start with a dielectric free energy functional $ \cal F$ with a cross term $ \propto \int\hspace{-0.5mm} d{\bi r}~{\bi p}_1\cdot{\bi p}_2$ , which was proposed by
Felderhof $ [$ J. Phys. C: Solid State Phys. {\bf 12}, 2423 (1979)$ ]$ . With this cross-coupling, our theory can
yield the theoretical results by Onsager and Kirkwood.
We also present dynamic equations
using the functional derivatives $ \delta {\cal F}/\delta {\bi p}_i$ to calculate the space-time correlations of $ {\bi p}_i$ . We then obtain analytic expressions for
various frequency-dependent quantities including the Debye formula. We find that the fluctuations of the total polarization drastically depend on whether we fix the electrode charge or the applied potential difference between parallel metal electrodes.
In the latter fixed-potential condition, we obtain a nonlocal (long-range) polarization correlation
inversely proportional to the cell volume $ V$ , which
is crucial to understand the dielectric response. It is produced by nonlocal charge fluctuations on the electrode surfaces and
is sensitive to the potential drops in the Stern layers in small systems. These nonlocal correlations in the bulk and on the surfaces are closely related due to the global constraint of fixed potential difference. We also add some results in other boundary conditions including the periodic one, where nonlocal correlations also appear.
Soft Condensed Matter (cond-mat.soft), Statistical Mechanics (cond-mat.stat-mech)
20 pages, 2 figures, accepted in J. Chem. Phys
One-third magnetization plateau in a spin-1 kagome magnet BaNi$_3$(AsO$_4$)$_2$(OH)$_2$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
Yuya Haraguchi, Jun-ichi Yamaura, Akira Matsuo, Koichi Kindo, Hiroko Aruga Katori
We investigate the structural and magnetic properties of BaNi$ _3$ (AsO$ _4$ )$ _2$ (OH)$ _2$ , focusing on its spin-1 kagome lattice and the intricate coexistence of ferromagnetic and antiferromagnetic interactions. Powder x-ray diffraction analysis confirms a highly crystalline trigonal structure. Detailed Rietveld refinement identifies a single crystallographic Ni site, indicative of a perfect kagome lattice. Magnetic susceptibility measurements suggest predominantly ferromagnetic interactions with an effective magnetic moment consistent with Ni$ ^{2+}$ spins, yet the system undergoes antiferromagnetic ordering at a N$ é$ el temperature of 5.8 K. Isothermal magnetization measurements reveal a series of metamagnetic transitions culminating in a plateau-like phase near one-third of the total saturation magnetization. Analysis of the phase boundaries shows that the antiferromagnetic phase supports a substantial net moment in each kagome layer, comparable to that of the one-third plateau. This observation challenges the conventional model-where a 120$ ^\circ$ ground state transitions to an up-up-down configuration-commonly assumed for kagome antiferromagnets. Instead, our findings indicate that both the zero-field ground state and the field-induced phases exhibit in-plane ferrimagnetic spin arrangements on the kagome lattice, with the metamagnetic transition corresponding to a shift from layer-by-layer antiferromagnetically aligned net moments to ferromagnetically aligned ones. This configuration is stabilized by bond frustration, a network of competing interactions that can favor both ferromagnetic and antiferromagnetic couplings, highlighting the essential role of frustration in governing the low-temperature magnetic behavior of spin-1 kagome systems.
Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci)
8 pages, 3 figure, accepted in Physical Review Materials
Criticality and Universality of Generalized Kuramoto Model
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
Zhongpu Qiu, Tianyi Wu, Sheng Fang, Jun Meng, Jingfang Fan
We explore synchronization transitions in even-$ D$ -dimensional generalized Kuramoto oscillators on both complete graphs and $ d$ -dimensional lattices. In the globally coupled system, analytical expansions of the self-consistency equations, incorporating finite-size corrections, reveal universal critical exponents $ \beta = 1/2$ and $ \bar{\nu} = 5/2$ for all even $ D$ , indicating an unconventional upper critical dimension $ d_u = 5$ . Extensive numerical simulations across multiple $ D$ confirm these theoretical predictions. For locally coupled systems, we develop a framework based on spin-wave theory and fluctuation-resolved functional network diagnostics, which captures criticality in entrainment transition. A modified Edwards-Anderson order parameter further validates the predicted exponents. This combined theoretical and numerical study uncovers a family of universality classes characterized by $ D$ -independent but $ d$ -dependent criticality, offering a unified perspective on symmetry and dimensionality in nonequilibrium synchronization phenomena.
Statistical Mechanics (cond-mat.stat-mech)
An Exactly Solvable Model of Phase-Fluctuating Superconductivity in Cuprates: The Role of Partially Flat Bands
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
Utilizing an exactly solvable Hubbard-like model that exhibits a pseudogap (PG) phase and a partially flat band, we perform self-consistent microscopic calculations of the superconductivity (SC) in cuprates, incorporating both thermal and zero-point superconducting phase fluctuations in the presence of long-range Coulomb interactions. The results reveal an important role of the partially flat band in determining phase-fluctuating SC as well as several key features that are consistent with experimental observations. Specifically, we find a dome-shaped $ d$ -wave superconducting region in the temperature-doping phase diagram with the optimal doping point located near the quantum critical point between the PG and the metallic phases. Near the optimal doping, the partially flat band suppresses and amplifies the fluctuation-induced destructing effect on the $ d_{x^2-y^2}$ - and $ d_{xy}$ -wave pairing, respectively, ensuring an absolutely dominant $ d_{x^2-y^2}$ -wave SC. While the phase fluctuations of the $ d_{x^2-y^2}$ -wave SC are relatively weak around optimal doping, they become significant in both underdoped and overdoped regimes. We then identify a discontinuity on the superconducting dome in underdoped regime that results from a transition from a strong- to a weak-phase-fluctuating state as doping approaches the optimal point.
Strongly Correlated Electrons (cond-mat.str-el), Superconductivity (cond-mat.supr-con)
Finite Membrane Thickness Influences Hydrodynamics on the Nanoscale
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Zachary G. Lipel, Yannick A. D. Omar, Dimitrios Fraggedakis
Many lipid membrane-mediated transport processes–such as mechanically-gated channel activation and solute transport–involve structural and dynamical features on membrane thickness length scales. Most existing membrane models, however, tend to adopt (quasi-)two-dimensional descriptions that neglect thickness-dependent phenomena relevant to internal membrane mechanics, and thus do not fully account for the complex coupling of lipid membranes with their surrounding fluid media. Therefore, explicitly incorporating membrane thickness effects in lipid membrane models will enable a more accurate description of the influence of membrane/fluid coupling on transport phenomena in the vicinity of the bilayer surfaces. Here, we present a continuum model for membrane fluctuations that accounts for finite membrane thickness and resolves hydrodynamic interactions between the bilayer and its surrounding fluid. By applying linear response analysis, we observe that membrane thickness-mediated effects, such as bending-induced lipid reorientations, can generate shear flows close to the membrane surface that slow down the relaxation of nanometer scale shape fluctuations. Additionally, we reveal the emergence of pressure inversion and flow reversal near the membrane interfaces, accompanied by localized stagnation points. Among these, extensional stagnation points give rise to a novel mode of bulk dissipation, originating from bending-induced compression and expansion of the membrane surfaces and their coupling to shear stresses in the fluid. Our findings identify membrane thickness as a key factor in nanoscale hydrodynamics and suggest that its effects may be detectable in fluctuation spectra and can be relevant to interfacial processes such as solute permeability and contact with solid boundaries or other membranes.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
7 pages, 2 figures
Development of precession Lorentz transmission electron microscopy
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Shunsuke Hayashi, Dongxue Han, Hidenori Tsuji, Kyoko Ishizaka, Asuka Nakamura
Lorentz transmission electron microscopy (LTEM) is a powerful tool for high-resolution imaging of magnetic textures, including their dynamics under external stimuli and ultrafast nonequilibrium conditions. However, magnetic imaging is often hindered by non-magnetic diffraction contrast arising from inhomogeneous sample deformation or a non-parallel electron beam. In this study, we develop a precession LTEM system that can suppress diffraction contrast by changing the incident angle of the electron beam relative to the sample in a precessional manner. By comparing LTEM images acquired at different precession angles ($ \theta$ ), we show that diffraction contrast is significantly reduced with increasing $ \theta$ . However, large $ \theta$ values lead to an undesired broadening of the magnetic contrast, highlighting the importance of optimizing $ \theta$ . Furthermore, defocus-dependent measurements reveal that magnetic contrast is particularly improved at small defocus values, suggesting that precession LTEM can achieve higher spatial resolution. These findings demonstrate the potential of precession LTEM as a powerful technique for studying magnetic dynamics.
Materials Science (cond-mat.mtrl-sci), Instrumentation and Detectors (physics.ins-det)
19 pages, 5 figures
Mitigating Singlet Exciton Back-Transfer using 2D Spacer Layers for Perovskite-Sensitised Upconversion
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Nicholas P. Sloane, Damon M. de Clercq, Md Arafat Mahmud, Jianghui Zheng, Adrian Mena, Michael P. Nielsen, Anita W.Y. Ho-Baillie, Christopher G. Bailey, Timothy W. Schmidt, Dane R. McCamey
Photon upconversion has potential applications in light-emitting diodes, photocatalysis, bio-imaging, microscopy, 3D printing, and photovoltaics. Bulk lead-halide perovskite films have emerged as promising sensitisers for solid-state photon upconversion via triplet-triplet annihilation due to their excellent optoelectronic properties. In this system, a perovskite sensitiser absorbs photons and subsequently generates triplet excitons in an adjacent emitter material, where triplet-triplet annihilation can occur allowing for the emission of higher energy photons. However, a major loss pathway in perovskite-sensitised upconversion is the back-transfer of singlet excitons from the emitter to the sensitiser via Förster Resonance Energy Transfer. In this investigation we introduce a 2D perovskite spacer layer between the bulk perovskite sensitiser and a rubrene emitter to mitigate back-transfer of singlet excitons from rubrene to the bulk perovskite sensitiser. This modification reveals the inherent balance between efficient triplet exciton transfer across the interface with a potential barrier versus the mitigation of near-field back-transfer by increasing the distance between the sensitiser and singlet excitons in the emitter. Notably, the introduction of this spacer layer enhances the relative upconversion efficiency at lower excitation power densities while also sustaining performance over extended timescales. This work represents significant progress toward the practical applications of perovskite-sensitised photon upconversion.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph)
Core-Ionized States and X-ray Photoelectron Spectra of Solids From Periodic Algebraic Diagrammatic Construction Theory
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Abdelrahman M. Ahmed, Alexander Yu. Sokolov
We present the first-ever implementation and benchmark of periodic algebraic diagrammatic construction theory (ADC) for core-ionized states and X-ray photoelectron spectra (XPS) in crystalline materials. Using a triple-zeta Gaussian basis set and accounting for finite-size and scalar relativistic effects, the strict and extended second-order ADC approximations (ADC(2) and ADC(2)-X) predict the core ionization energies of weakly correlated solids within ~ 1.5 and 0.5 eV of experimental measurements, respectively. We further demonstrate that the ADC(2)-X method can capture the satellite features in XPS spectra of graphite, cubic and hexagonal boron nitride, and TiO2, albeit significantly overestimating their energies. The ADC(2)-X calculations reveal that the satellite transitions display strong configuration interaction with excitations involving several frontier orbitals delocalized in phase space. Our work demonstrates that ADC is a promising first-principles approach for simulating the core-excited states and X-ray spectra of materials, highlighting its potential and motivating further development.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
Atypical Ferrimagnetism in the case of Ni$_4$Nb$_2$O$_9$
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Jhuma Sannigrahi, Roumita Roy, Richard Waite, Anupam Banerjee, Mohamad Numan, Manh Duc Le, D. T. Adroja, Dmitry Khalyavin, Sudipta Kanungo, Subham Majumdar
Ferrimagnetism typically emerges from chemically distinct magnetic ions or mixed-valence states. In contrast, we discover an unconventional route to ferrimagnetism in Ni4Nb2O9, where identical Ni(2+) ions at crystallographically equivalent positions develop unequal magnetic moments purely due to differences in their local environments. Through a synergy of powder neutron diffraction, inelastic neutron scattering, first-principle-based calculations, we reveal that the Ni(A) and Ni(B) sublattices, despite sharing the same nominal valence, differ in octahedral distortion, magnetic dimensionality, and electronic structure. Ni(A) exhibits a quasi one-dimensional character, enhanced p-d hybridization, and reduced magnetic moment due to spin delocalization onto oxygen, while Ni(B) retains a nearly two-dimensional geometry and a full spin-1 moment. Our findings demonstrate that structural and electronic inequivalence alone can induce ferrimagnetism, offering a new design principle for materials with controllable magnetic compensation and anisotropy relevant for spintronic applications and beyond.
Materials Science (cond-mat.mtrl-sci)
9 pages, 6 figures, regular article
Low-dimensional Bose-Bose Mixture in Random Speckle Potential
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-12 20:00 EDT
Avra Banerjee, Saswata Sahu, Dwipesh Majumder
In this work, we have studied the effect of the repulsive speckle potential in a mixture of Bose-Einstein condensates in one dimension (1D) and two dimension (2D). We simulated linear and circular random speckle potentials in 1D and 2D, respectively. Our calculation shows that the condensate density forms a sharp ring in 2D, and the condensate is divided into two parts in 1D at a high impurity density of speckle potential. We have calculated the energy and chemical potential of the system by solving the Gross-Pitaevskii (GP) equation to see the stability of the condensate. In our study, we have seen that the nature of the impurity response is the same for one-dimensional and two-dimensional quantum droplets.
Quantum Gases (cond-mat.quant-gas), Atomic Physics (physics.atom-ph)
Journal Of Technology 13, 301 (2025)
Experimental Investigation of a Bipartite Quench in a 1D Bose gas
New Submission | Quantum Gases (cond-mat.quant-gas) | 2025-05-12 20:00 EDT
Léa Dubois, Guillaume Thémèze, Jérôme Dubail, Isabelle Bouchoule
Long wavelength dynamics of 1D Bose gases with repulsive contact interactions can be captured by Generalized HydroDynamics (GHD) which predicts the evolution of the local rapidity distribution. The latter corresponds to the momentum distribution of quasiparticles, which have infinite lifetime owing to the integrability of the system. Here we experimentally investigate the dynamics for an initial situation that is the junction of two semi-infinite systems in different stationary states, a protocol referred to as “bipartite quench” protocol. More precisely we realise the particular case where one half of the system is the vacuum state. We show that the evolution of the boundary density profile exhibits ballistic dynamics obeying the Euler hydrodynamic scaling. The boundary profiles are similar to the ones predicted with zero-temperature GHD in the quasi-BEC regime, with deviations due to non-zero entropy effects. We show that this protocol, provided the boundary profile is measured with infinite precision, permits to reconstruct the rapidity distribution of the initial state. For our data, we extract the initial rapidity distribution by fitting the boundary profile and we use a 3-parameter ansatz that goes beyond the thermal assumption. Finally, we investigate the local rapidity distribution inside the boundary profile, which, according to GHD, presents, on one side, features of zero-entropy states. The measured distribution shows the asymmetry predicted by GHD, although unelucidated deviations remain.
Quantum Gases (cond-mat.quant-gas), Quantum Physics (quant-ph)
16 pages, 7 figures
Diverse electronic phases correlated with twist-angle distribution and pseudomagnetic field in turbostratic graphene
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Mona Garg, Ankit Kumar, Deepti Rana, Anmol Arya, Aswini R, Umesh Waghmare, G. U. Kulkarni, Goutam Sheet
Twisted multilayer graphene has become a focal point of research due to its ability to host a range of quantum phases, including unconventional superconductivity, ferromagnetism, and strong correlation effects. In the present work, we address the challenge of investigating the diverse physics associated with a variety of twist-angles in a simple graphene platform which is economic and bypasses the tedious process of fabricating multiple devices, each with one twist angle. We used turbostratic graphene films containing a variety of twist angles characterized by distinct Moiré patterns observed through scanning tunneling microscopy (STM), and distinct signatures recorded by Raman spectroscopy. From scanning tunneling spectroscopy (STS), we show that the local twist angles remarkably correlate with the characteristic local electronic properties. Most remarkably, the films spontaneously generate strained wrinkles during growth, with certain wrinkled regions exhibiting robust strain-induced pseudo-magnetic fields, as recorded by ultra-low temperature STS.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
26 pages, 17 figures
Ab initio X-ray Near-Edge Spectroscopy of Sodium-Based Multi-Alkali Antimonides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Chung Xu, Richard Schier, Caterina Cocchi
Multi-alkali antimonides (MAAs) are promising materials for vacuum electron sources. While sodium-based MAAs have demonstrated superior characteristics for ultrabright electron sources, their synthesis remains challenging, often resulting in mixed stoichiometries and polycrystalline domains. To address this complexity and guide the characterization of experimentally grown photocathodes, we present a comprehensive theoretical study of the X-ray near-edge spectroscopy (XANES) of four ternary MAAs: cubic Na$ _2$ KSb and hexagonal NaK$ _2$ Sb, representing the experimentally known phase of each stoichiometry, as well as hexagonal Na$ _2$ KSb and cubic NaK$ _2$ Sb, two computationally predicted polymorphs. Employing state-of-the-art ab initio methods based on all-electron density-functional theory and the solution of the Bethe-Salpeter equation (BSE), we compute and analyze the XANES at the sodium and potassium K-edges, potassium L$ _{2,3}$ -edge, and antimony K and L$ _2$ -edges. Our analysis reveals distinct spectral fingerprints for the experimentally known phases, cubic Na$ _2$ KSb and hexagonal NaK$ _2$ Sb, particularly at the sodium K-edge and potassium L$ _{2,3}$ -edge, providing useful indications for their identification in complex samples. We further investigate the role of excitonic effects by comparing BSE spectra and their counterparts obtained in the independent-particle approximation, highlighting their significant influence on the near-edge features, especially for shallower core levels. Our findings offer a useful theoretical benchmark for the experimental characterization and diagnostics of sodium-based MAA photocathodes.
Materials Science (cond-mat.mtrl-sci)
Directed light emission from monolayers on 2D materials via optical interferences
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Pavel Trofimov, Sabrina Juergensen, Adrián Dewambrechies Fernández, Kirill Bolotin, Stephanie Reich, Hélène Seiler
Two-dimensional materials provide a rich platform to explore phenomena such as emerging electronic and excitonic states, strong light-matter coupling and new optoelectronic device concepts. The optical response of monolayers is entangled with the substrate on which they are grown or deposited on, often a two-dimensional material itself. Understanding how the properties of the two-dimensional monolayers can be tuned via the substrate is therefore essential. Here we employ angle-resolved reflectivity and photoluminescence spectroscopy on highly ordered molecular monolayers on hexagonal boron nitride (hBN) to systematically investigate the angle-dependent optical response as a function of the thickness of the hBN flake. We observe that light reflection and emission occur in a strongly directed fashion and that the direction of light reflection and emission is dictated by the hBN flake thickness. Transfer matrix simulations reproduce the experimental data and show that optical interference effects in hBN are at the origin of the angle-dependent optical properties. While our study focuses on molecular monolayers on hBN, our findings are general and relevant for any 2D material placed on top of a substrate. Our findings demonstrate the need to carefully choose substrate parameters for a given experimental geometry but also highlight opportunities in applications such as lighting technology where the direction of light emission can be controlled via substrate thickness.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Materials Science (cond-mat.mtrl-sci)
Inferring charge noise source locations from correlations in spin qubits
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Juan S. Rojas-Arias, Akito Noiri, Jun Yoneda, Peter Stano, Takashi Nakajima, Kenta Takeda, Takashi Kobayashi, Giordano Scappucci, Seigo Tarucha, Daniel Loss
We investigate low-frequency noise in a spin-qubit device made in isotopically purified Si/Si-Ge. Observing sizable cross-correlations among energy fluctuations of different qubits, we conclude that these fluctuations are dominated by charge noise. At low frequencies, the noise spectra do not fit well a power law; rather, we can recognize a few individual two-level fluctuators (TLFs). We demonstrate that the noise cross-correlations allow one to get information on the spatial location of such individual TLFs.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Quantum Physics (quant-ph)
Main text: 6 pages, 4 figures. Supplemental material: 6 pages, 7 figures
Quantum Monte Carlo study of the quasiparticle effective mass of the two-dimensional uniform electron liquid
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
S. Azadi, N.D. Drummond, A. Principi, R.V. Belosludov, M.S. Bahramy
The real-space variation quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) are used to calculate the quasiparticle energy bands and the quasiparticle effective mass of the paramagnetic and ferromagnetic two-dimensional uniform electron liquid (2D-UEL)@. The many-body finite-size errors are minimized by performing simulations for three system sizes with the number of electrons $ N=146$ , 218, and 302 for paramagnetic and $ N=151$ for ferromagnetic systems. We consider 2D-UEL to be within the metallic density range $ 1\leq r_s \leq 5$ . The VMC and DMC results predict that the quasiparticle effective mass $ m^\ast$ of the paramagnetic 2D-UEL at high density $ r_s=1$ is very close to 1, suggesting that effective mass renormalization due to electron-electron interaction is negligible. We find that $ m^\ast$ of the paramagnetic 2D-UEL obtained by the VMC and DMC methods increases by $ r_s$ but with different slopes. Our VMC and DMC results for ferromagnetic 2D-UEL indicate that $ m^\ast$ decreases rapidly by reducing the density due to the strong suppression of the electron-electron interaction.
Strongly Correlated Electrons (cond-mat.str-el), Plasma Physics (physics.plasm-ph), Quantum Physics (quant-ph)
Algorithm for finding local integrals of motion in quantum lattice models in the thermodynamic limit
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
J. Pawlowski, J. Herbrych, M. Mierzejewski
Local integrals of motion (LIOMs) play a key role in understanding the stationary states of closed macroscopic systems. They were found for selected integrable systems via complex analytical calculations. The existence of LIOMs and their structure can also be studied via numerical methods, which, however, involve exact diagonalization of Hamiltonians, posing a bottleneck for such studies. We show that finding LIOMs in translationally invariant lattice models or unitary quantum circuits can be reduced to a problem for which one may numerically find an exact solution also in the thermodynamic limit. We develop and implement a simple algorithm and demonstrate the efficiency of this method by calculating LIOMs and the Mazur bounds for infinite integrable spin chains and unitary circuits. Finally, we demonstrate that this approach correctly identifies approximate LIOMs in nearly integrable spin ladders.
Strongly Correlated Electrons (cond-mat.str-el), Quantum Physics (quant-ph)
Supplemental GitHub repository with code: this https URL
Quantum Monte Carlo description of correlated electrons in two-dimensional FeSe
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
S. Azadi, A. Principi, R. V. Belosludov, T. D. Kühne, M.S. Bahramy
Electronic correlation effects on the structural properties of double-layer FeSe are studied using variation and diffusion quantum Monte Carlo methods. The Slater-Jastrow many-body wavefunction with two different forms for the homogeneous two-body pair-correlation term is used. The ground-state energy of the system is obtained at the thermodynamic limit using two different trial wave functions called JDFT and JSD. Only the Jastrow factor is fully optimized in the JDFT wave function, while the Slater determinant comes from the density functional approximation. In the JSD trial wave function, the Slater determinant and the Jastrow factor are fully optimized simultaneously. We calculated the VMC and DMC energies as a function of interlayer separation for two different in-plane iron-iron bond lengths. Our QMC results indicate that the optimized interlayer separation decreases with increasing iron-iron bond length, driven by stretch. We found that a three- to two-dimensional phase transition increases the electron-electron correlation effects and shifts the system from moderately correlated to strongly correlated. The value of correlation energy implies that the Hubbard $ U$ value, which is widely used in DFT+U calculations, for two-dimensional FeSe is larger than its value in bulk.
Strongly Correlated Electrons (cond-mat.str-el), Other Condensed Matter (cond-mat.other), Quantum Physics (quant-ph)
Bipolar doping in van der Waals semiconductor through Flexo-doping
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Bo Zhang, Hui Xia, Zhengdong Huang, Yaqian Liu, Jun Kang, Liaoxin Sun, Tianxin Li, Su-Huai Wei, Wei Lu
Doping plays a key role in functionalizing semiconductor devices, yet traditional chemical approaches relying on foreign-atom incorporation suffer from doping-asymmetry, pronounced lattice disorder and constrained spatial resolution. Here, we demonstrate a physical doping technique to directly write nanoscale doping patterns into layered semiconductors (MoS2). By applying localized tensile and compressive stress via an atomic force microscopy probe, p and n type conductance are simultaneously written into the designed area with sub-100-nm resolution, as verified by spatially resolved capacitance and photocurrent experiments. Density functional theory calculations reveal strain-driven shifts of donor and acceptor levels, as large as several hundreds of meV, linking mechanical stress to semiconductor doping. Fabricated strain-engineered junction efficiently rectifies the current flow and performs logic operations with stable dynamic response. This strain-driven approach enables spatially precise doping in van der Waals materials without degrading crystallinity, offering a versatile platform for nanoscale semiconductor devices.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Topological Devil’s staircase in a constrained kagome Ising antiferromagnet
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
Afonso Rufino, Samuel Nyckees, Jeanne Colbois, Frédéric Mila
We show that the constrained Ising model on the kagome lattice with infinite first and third neighbor couplings undergoes an infinite series of thermal first-order transitions at which, as in the Kasteleyn transition, linear defects of infinite length condense. However, their density undergoes abrupt jumps because of the peculiar structure of the low temperature phase, which is only partially ordered and hosts a finite density of zero-energy domain walls. The number of linear defects between consecutive zero-energy domain walls is quantized to integer values, leading to a devil’s staircase of topological origin. By contrast to the devil’s staircase of the ANNNI and related models, the wave-vector is not fixed to commensurate values inside each phase.
Strongly Correlated Electrons (cond-mat.str-el), Statistical Mechanics (cond-mat.stat-mech)
Elastic properties of transition metal dichalcogenides
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
S. Azadi, A. Azhar, R. V. Belosludov, T. D. Kühne, M.S. Bahramy
We present a comprehensive first-principles study of the structural and elastic properties of 2H-MX$ _2$ transition metal dichalcogenides (TMDs) (M = W, Mo, Ta, Nb; X = S, Se). Using density functional theory with various van der Waals exchange-correlation functionals, we systematically investigate the influence of nonlocal interactions on lattice parameters, elastic constants, and mechanical moduli. Our results reveal a fundamental distinction between semiconducting and metallic TMDs: metallic compounds exhibit larger in-plane lattice parameters and reduced interlayer spacing, consistent with their bonding characteristics. We find that metallic TMDs display significantly lower in-plane stiffness and shear modulus compared to their semiconducting counterparts. We discuss this behaviour in the context of the observed charge density waves. In addition, we establish clear trends in the bulk, Young’s, and shear moduli, demonstrating the role of atomic number and chemical composition in determining mechanical stability.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Efficient parallel algorithms for free-energy calculation of millions of water molecules in the fluid phases
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
Luis Enrique Coronas, Oriol Vilanova, Giancarlo Franzese
Simulating water droplets made up of millions of molecules and on timescales as needed in biological and technological applications is challenging due to the difficulty of balancing accuracy with computational capabilities. Most detailed descriptions, such as ab initio, polarizable, or rigid models, are typically constrained to a few hundred (for ab initio) or thousands of molecules (for rigid models). Recent machine learning approaches allow for the simulation of up to 4 million molecules with ab initio accuracy but only for tens of nanoseconds, even if parallelized across hundreds of GPUs. In contrast, coarse-grained models permit simulations on a larger scale but at the expense of accuracy or transferability. Here, we consider the CVF molecular model of fluid water, which bridges the gap between accuracy and efficiency for free-energy and thermodynamic quantities due to i) a detailed calculation of the hydrogen bond contributions at the molecular level, including cooperative effects, and ii) coarse-graining of the translational and rotational degrees of freedom of the molecules. The CVF model can reproduce the experimental equation of state and fluctuations of fluid water across a temperature range of 60 degrees around ambient temperature and from 0 to 50 MPa. In this work, we describe efficient parallel Monte Carlo algorithms executed on GPUs using CUDA, tailored explicitly for the CVF model. We benchmark accessible sizes of 17 million molecules with the Metropolis and 2 million with the Swendsen-Wang Monte Carlo algorithm.
Statistical Mechanics (cond-mat.stat-mech)
29 pages, 9 figures
Magnetic anisotropy related to hybridization between Fe 3$d$ and As 4$p$ orbitals in a bcc Fe-As thin film
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Takahito Takeda, Karumuri Sriharsha, Seiji Aota, Ryo Okano, Le Duc Anh, Yukiharu Takeda, Akira Yasui, Miho Kitamura, Yuki K. Wakabayashi, Atsushi Fujimori, Masaaki Tanaka, Masaki Kobayashi
The magnetic anisotropy (MA) of Fe-based ferromagnetic thin films has been extensively studied for device applications. The examined material is a new Fe-based ferromagnetic thin film, bcc Fe$ {1-x}$ As$ x$ (Fe-As) with the in-plane MA (IMA) grown on a GaAs (111)B substrate. The magnetic properties of the Fe-As thin film have been investigated by Xray magnetic circular dichroism (XMCD) and magnetic circular dichroism in hard X-ray photoemission spectroscopy (MCD-HAXPES) to elucidate the role of As ions in the IMA. The XMCD spectra at the Fe $ L{2,3}$ edge and MCD-HAXPES spectra of the Fe 2$ p$ core level exhibit ferromagnetic and metallic features like Fe metal. The XMCD at the As $ L{2,3}$ edge demonstrates that the As ions contribute to the ferromagnetism of bcc Fe-As through the hybridization between the Fe 3$ d$ and As 4$ p$ orbitals. The estimations of the magnetic moments of Fe using the XMCD sum rules have revealed that the orbital magnetic moment is isotropic and the magnetic dipole term is anisotropic. The anisotropy of the magnetic dipole term can be attributed to the anisotropic $ p-d$ hybridization due to epitaxial strain, contributing to the IMA of bcc Fe-As. Our findings enlighten the mechanism of the MA of the non-magnetic ion-doped bcc Fe thin film, which can be applied to other magnetic 3$ d$ transition metal thin films doped with non-magnetic elements.
Materials Science (cond-mat.mtrl-sci)
Synthetic gauge field enabled realization of bulk- and edge-transported states in an aperiodic acoustic structure
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Y. X. Fang, W. H. Zhu, Y. Cai, X. H. Li, M. Q. Zhang, J. Huang, Y. Li, S. Q. Wu
Topologically protected edge states with immunity against various disorders have been implemented in a variety of topological insulators. In this Letter, we reveal that Landau levels in aperiodic acoustic structures can be achieved under different pseudomagnetic fields (PMFs). The produced zero order Landau modes (ZOLMs) could transmit along the channels at the interior or exterior of the inhomogeneous array, which are separately termed as “bulk-transported states” (BTSs) and “edge-transported states” (ETSs). Distinct from conventional valley edge states, the ZOLMs show intriguing self-collimation feature. If a pseudoelectric field (PEF) is further included, the combination of a PMF and PEF can result in the formation of bulk or edge Landau rainbow, where Landau zero modes are distributed at various positions of the bulk or boundary of the sample at different frequencies. The synthetic-gauge-field-controlled topological states can enable fully control of robust transmission, and using the entire footprint of a topological lattice. Our findings not only profoundly advance the current understanding of topological phase matter but also offer new avenues for constructing topological acoustic devices.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optics (physics.optics)
19 pages, 7 figures
Luminescent Platform for Thermal Sensing and Imaging Based on Structural Phase-Transition
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Anam Javaid, Maja Szymczak, Malgorzata Kubicka, Vasyl Kinzhybalo, Marek Drozd, Damian Szymanski, Lukasz Marciniak
The remarkable sensitivity of the luminescent properties of Eu3+ ions to structural changes in host materials has been well-explored for years. However, the application of this feature of Eu3+ in materials exhibiting thermally induced structural phase transitions for the development of luminescent thermometers has only recently been proposed. The narrow operating range of such thermometers necessitates the exploration of new host materials. In response to this demand, this study carefully analyzes the spectroscopic properties of X as a function of temperature and dopant ion concentration. As demonstrated, X undergoes a phase transition from a low-temperature monoclinic phase to a high-temperature trigonal structure, resulting in significant changes in both the emission spectrum shape of Eu ions and the depopulation kinetics of the 5D0 level. Consequently, X can be utilized as both a ratiometric and a lifetime-based luminescence thermometer, achieving maximal relative sensitivities of 3.4 and 1.0 or the respective approaches. Additionally, this work highlights how increasing the concentration of Eu3+ ions enables the tuning of the thermal operating range to achieve optimal thermometric performance. Moreover, an implementation of ratiometric approach of temperature sensing and imaging with X using digital camera without filters was demonstrated. This is the first report that demonstrates thermal imaging using Eu3+-solely doped phosphor. This finding underscores the potential of X as a versatile host material for advanced luminescent thermometry applications.
Materials Science (cond-mat.mtrl-sci)
Generation of non-equilibrium spin-motive force at the surface of a topological insulator induced by current-driven domain wall motion in the magnetic substrate
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Reza Fazeli Mehrabani, Babak Abdollahipour, Hakimeh Mohammadpour, Arash Phirouznia
The generalized Faraday method can be used for computation of spin-motive force (SMF) within the unitary transformation approach. Meanwhile, the unitary transformation approach, which could be employed to obtain an effective collinear exchange interaction of non-collinear magnetic structures, cannot be used when the other parts of the Hamiltonian contain spin-dependent couplings. In the current study, the method of unitary transformation has been generalized to systems with spin-momentum coupling. In this way, the SMF at topological insulator surfaces has been computed analytically.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Surface mobility of a glass-forming polymer in an ionic liquid
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Xinyu Zhang (CUHK), Christian Pedersen (UiO), Haoqi Zhu (CUHK), Siming Wang (CUHK), Yuchen Fu (CUHK), Liang Dai (CUHK), Andreas Carlson (UiO), Thomas Salez (LOMA), Yu Chai (CUHK)
The free surface of glassy polymers exhibits enhanced segmental dynamics compared to the bulk, forming a liquid-like layer that lowers the glass transition temperature (Tg) in nanometersized polymer samples. Recent studies have shown that immersing polymers in ionic liquids can suppress this enhanced surface dynamics. To investigate how ionic liquids influence polymer dynamics near the ionic-liquid-polymer interface, we measure the surface leveling of nanometersized stepped polystyrene films immersed in ionic liquids, and compared the results to the case of films in vacuum. Our results reveal that ionic liquids significantly slow the leveling process both above and below Tg. However, our results indicate that the liquid-like surface layer below Tg does exist in ionic liquids. Numerical solutions of the thin-film equation, incorporating appropriate boundary conditions, show that the surface mobility of PS films in ionic liquids can match that of PS films in vacuum. Thus, while ionic liquids alter the polymer flow process, they do not eliminate the dynamical heterogeneity inherent to glassy polymers.
Soft Condensed Matter (cond-mat.soft), Classical Physics (physics.class-ph)
Unravelling the Antimicrobial Action Mechanism of Ribosomal Protein S30
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
J. Bhatt Mitra, V. K. Sharma, M. Kumar, V. Garcia Sakai, A. Mukherjee
Ribosomal protein S30 (RS30) exhibits potent antimicrobial activity against a broad spectrum of bacteria. Despite its efficacy, the underlying action mechanism remained elusive. In this study, we unravel the fundamental mechanism by which RS30 exerts its bactericidal effects, using a combination of microbiological assays and advanced biophysical techniques. Microbiological analyses reveal that RS30 kills bacteria primarily through membrane depolarization, despite limited membrane permeabilization, indicating an unconventional mode of action involving no or partial lysis of the membrane. Importantly, RS30 demonstrates time-dependent bactericidal activity with no detectable cytotoxicity toward mammalian cells, underscoring its high selectivity. This selective action was further confirmed using biophysical experiments on model membrane systems composed of anionic (bacterial mimic) and zwitterionic (mammalian mimic) phospholipids. Our measurements suggested that RS30 preferentially binds to anionic membranes via electrostatic interactions, undergoes a conformational transition from a random coil to an {\alpha}-helix upon binding, and induces vesicle aggregation. Quasielastic neutron scattering (QENS) measurements provide microscopic insights, showing that RS30 significantly restricts the lateral diffusion of anionic lipids, thereby perturbing membrane dynamics and increasing susceptibility to external stress. Together, our findings uncover important insights into the antimicrobial action mechanism of RS30, characterized by selective membrane interaction, structural transformation, and dynamic modulation of lipid membranes.
Soft Condensed Matter (cond-mat.soft)
Periodic implementation of the random phase approximation with numerical atomic orbitals and dual reciprocal space grids
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Edoardo Spadetto, Pier Herman Theodoor Philipsen, Arno Förster, Lucas Visscher
The random phase approximation (RPA) has emerged as a prominent first-principles method in material science, particularly to study the adsorption and chemisorption of small molecules on surfaces. However, its widespread application is hampered by its relatively high computational cost. Here, we present a well-parallelised implementation of the RPA with localised atomic orbitals and pair-atomic density fitting, which is especially suitable for studying two-dimensional systems. Through a dual $ \textbf{k}$ -grid scheme, we achieve fast and reliable convergence of RPA correlation energies to the thermodynamic limit. We demonstrate the efficacy of our implementation through an application to the adsorption of CO on MgO(001) using PBE input orbitals (RPA@PBE) Our calculated adsorption energy in in good agreement with previously published RPA@PBE studies, but, as expected, overestimates the experimentally available adsorption energies as well as recent CCSD(T) results.
Materials Science (cond-mat.mtrl-sci), Chemical Physics (physics.chem-ph)
many pages and figures
Engineering Morphologies of Metal Colloidal Assemblies via Colloid Jamming at Liquid-Liquid Interfaces
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Jiyuan Yao, Shuting Xie, Shijian Huang, Weilong Xu, Jiaqin Li, Zhenping Liu, Mingliang Jin, Loes I. Segerink, Lingling Shui, Sergii Pud
Self-assemblies, structured via nanoparticles, show promise as materials for advanced applications, like photonic devices, electrochemical energy storage units and catalysis support. Despite observing diverse morphologies, a comprehensive understanding of the formation mechanism remains elusive. In this work, we show that the coordination interaction between metal sulfide nanoparticles (MS NPs) and the fluorosurfactants at the droplet interface influences the morphology during the evaporation-induced self-assembly facilitated by droplet microfluidics. Further investigation into fluorosurfactants with various chemical groups and MS NPs reveals that the strength of coordination interactions significantly influences assembly morphology. The interfacial interactions can be eliminated through coating a SiO2 layer on the metal colloid (M@SiO2 NPs). In addition, we demonstrate that the morphologies of the self-assemblies can be engineered via the coordination interactions between the MS NPs and fluorosurfactants, and by varying the concentrations of MS NPs. Utilizing these interfacial interactions, assemblies with core-shell and homogeneous distribution of binary nanoparticles were constructed. Our findings offer novel insights into the interfacial jamming of nanoparticles at the droplet interface through evaporation-induced self-assembly, and into the design of metal colloidal assemblies with diverse morphologies, crucial for developing novel functional assemblies for catalysis, plasmonic, and porous materials in a controlled manner.
Soft Condensed Matter (cond-mat.soft)
An Extension of the Adiabatic Theorem
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
We examine the validity of a potential extension of the adiabatic theorem to quantum quenches, i.e., non-adiabatic changes. In particular, the Transverse Field Ising Model (TFIM) and the Axial Next Nearest Neighbour Ising (ANNNI) model are studied. The proposed extension of the adiabatic theorem is stated as follows: Consider the overlap between the initial ground state and the post-quench Hamiltonian eigenstates for quenches within the same phase. This overlap is largest for the post-quench ground state. In the case of the TFIM, this conjecture is confirmed for both the paramagnetic and ferromagnetic phases numerically and analytically. In the ANNNI model, the conjecture could be analytically proven for a special case. Numerical methods were employed to investigate the conjecture’s validity beyond this special case.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
13 pages, 14 figures
Polymer-Shell Coating of Mie-Resonant Silicon Nanospheres for Controlled Fabrication of Self-Assembled Monolayer
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Oanh Vu, Jialu Song, Hiroshi Sugimoto, Minoru Fujii
A polymer shell offers a unique opportunity to tailor structural and optical properties of optically functional nanoparticles and their ensembles. Here, we develop a process to coat Mie-resonant silicon nanospheres (Si NSs) with a thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel shell. We show formation of a PNIPAM shell of controlled thickness from the change of the hydrodynamic diameter and study the effect of thermoresponsive shrinkage and expansion of the shell on the Mie resonance of a Si NS. We then demonstrate that Si NSs with PNIPAM shells enable fabrication of cluster-free, self-assembled monolayers of Si NSs, in which distances between NSs are controlled by the PNIPAM shell thickness.
Materials Science (cond-mat.mtrl-sci), Optics (physics.optics)
Surface Nematic Uniformity
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Andrea Pedrini, Epifanio G. Virga
An ant-like observer confined to a two-dimensional surface traversed by stripes would wonder whether this striped landscape could be devised in such a way as to appear to be the same wherever they go. Differently stated, this is the problem studied in this paper. In a more technical jargon, we determine all possible uniform nematic fields on a smooth surface. It was already known that for such a field to exist, the surface must have constant negative Gaussian curvature. Here, we show that all uniform nematic fields on such a surface are parallel transported (in Levi-Civita’s sense) by special systems of geodesics, which (with scant inventiveness) are termed uniform. We prove that, for every geodesic on the surface, there are two systems of uniform geodesics that include it; they are conventionally called right and left, to allude at a possible intrinsic definition of handedness. We found explicitly all uniform fields for Beltrami’s pseudosphere. Since both geodesics and uniformity are preserved under isometries, by a classical theorem of Minding, the solution for the pseudosphere carries over all other admissible surfaces, thus providing a general solution to the problem (at least in principle).
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph)
Synthetic spin-orbit coupling in superconductor-semiconductor hybrid nanowires with micromagnet arrays
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
M.P. Hynes, D. Burke, K. Ganesh, A. Vekris, B.J. Villis, J.C. Gartside, T. Kanne, J. Nygård, K. Moors, W.R. Branford, M.R. Connolly, M.R. Buitelaar
Spin-orbit interaction accounts for the coupling of momentum and spin degrees of freedom of electrons and holes in semiconductor materials. In quantum information processing, it allows for electrical control of spin states and for the engineering of topologically protected Majorana zero modes. Although such functionalities were previously considered to be limited to semiconductor materials with strong intrinsic spin-orbit interactions only, recent theoretical work proposes using external rotating magnetic fields to engineer synthetic spin-orbit coupling. This would relax material constraints and open up new research directions for materials with low intrinsic spin-orbit interaction or augment existing spin-orbit interaction in materials in which this interaction is already strong. Here we demonstrate the feasibility of this approach and introduce rotating magnetic fields along an InAs/Al hybrid nanowire using permalloy micromagnet arrays which yields an estimated synthetic Rashba spin-orbit interaction coefficient of 0.022 eV nm. We use transport spectroscopy and the energy dependence of Andreev bound states in the nanowires as a probe of the magnetic field profiles of the micromagnets which are reconfigurably prepared in parallel or antiparallel magnetization configurations.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Electron Spin Resonance of Eu on triangular layers in EuT2P2 (T =Mn, Zn, Cd)
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
Jörg Sichelschmidt, Pierre Chailloleau, Sarah Krebber, Asmaa El Mard, Cornelius Krellner, Kristin Kliemt
We report on the electron spin resonance (ESR) of Eu$ ^{2+}$ in Eu$ T_{2}$ P$ {2}$ ($ T$ =Mn, Zn, Cd) single crystals. The temperature dependencies of ESR linewidth and resonance shift show a similar behaviour when approaching the Eu-ordered state – a divergence towards $ T{\rm N}$ , indicating the growing importance of magnetic correlations and the build-up of internal magnetic fields. For $ T$ =Mn an additional temperature scale of $ \approx 47$ ~K has considerable impact on linewidth, resonance field and intensity. This points to the presence of Mn magnetic correlations which yet were not reported.
Strongly Correlated Electrons (cond-mat.str-el)
7 pages, 3 figures, ICM 2024 proceedings
Modeling complex particle suspensions: perspectives on the rigid multiblob method
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Blaise Delmotte, Florencio Balboa Usabiaga
Many suspensions contain particles with complex shapes that are affected not only by hydrodynamics, but also by thermal fluctuations, internal kinematic constraints and other long-range non-hydrodynamic interactions. Modeling these systems represents a significant numerical challenge due to the interplay between different effects and the need to accurately capture multiscale phenomena. In this article we review recent developments to model large suspensions of particles of arbitrary shapes and multiple couplings with controllable accuracy within the rigid multiblob framework. We discuss the governing equations, highlight key numerical developments, and illustrate applications ranging from microswimmers to complex colloidal suspensions. This review illustrates the effectiveness and versatility of the rigid multiblob method in tackling a wide range of physical problems in fluid mechanics, soft matter physics, biophysics, materials and colloidal science.
Soft Condensed Matter (cond-mat.soft)
24 pages, 8 figures
Engineering inter-band coupling in a two-band superconductor by topological defects
New Submission | Superconductivity (cond-mat.supr-con) | 2025-05-12 20:00 EDT
Thomas Gozlinski, Qili Li, Rolf Heid, Oleg Kurnosikov, Alexander Haas, Ryohei Nemoto, Toyo Kazu Yamada, Joerg Schmalian, Wulf Wulfhekel
The vast majority of superconductors have more than one Fermi surface, on which the electrons pair below the critical temperature TC, yet their superconducting behavior can be well described by a single-band Bardeen-Cooper-Schrieffer theory. This is mostly due to inter-band scattering, especially in superconductors in the dirty limit, rigidly linking the pairing amplitude of the different bands. This effect has severely limited experimental studies of the complex physics of multi-band superconductivity. In this study, we utilize the fact that elementary Pb - as a clean limit system - has two Fermi surfaces that are only weakly coupled by inter-band scattering, allowing the formation of two separate condensates. By studying elementary crystal defects in the form of stacking faults with our millikelvin scanning tunneling microscope, we show how to locally tune inter-band coupling ranging from weak to strong coupling and modify the superconducting order parameters around defects. The experiments critically test the theory of multi-band superconductors and give a route to access a wide range of predicted quantum effects in these systems.
Superconductivity (cond-mat.supr-con), Materials Science (cond-mat.mtrl-sci)
Main text: 21 pages, 4 figures; Supplementary Material: 14 pages, 12 figures
The role of non-equilibrium populations in dark exciton formation
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Paul Werner, Wiebke Bennecke, Jan Philipp Bange, Giuseppe Meneghini, David Schmitt, Marco Merboldt, Anna M. Seiler, AbdulAziz AlMutairi, Kenji Watanabe, Takashi Taniguchi, G. S. Matthijs Jansen, Junde Liu, Daniel Steil, Stephan Hofmann, R. Thomas Weitz, Ermin Malic, Stefan Mathias, Marcel Reutzel
In two-dimensional transition metal dichalcogenide structures, the optical excitation of a bright exciton may be followed by the formation of a plethora of lower energy dark states. In these formation and relaxation processes between different exciton species, non-equilibrium exciton and phonon populations play a dominant role, but remain so far largely unexplored as most states are inaccessible by regular spectroscopies. Here, on the example of homobilayer 2H-MoS$ _2$ , we realize direct access to the full exciton relaxation cascade from experiment and theory. By measuring the energy- and in-plane momentum-resolved photoemission spectral function, we reveal a distinct fingerprint for dark excitons in a non-equilibrium excitonic occupation distribution. In excellent agreement with microscopic many-particle calculations, we quantify the timescales for the formation of a non-equilibrium dark excitonic occupation and its subsequent thermalization to 85fs and 150fs, respectively. Our results provide a previously inaccessible view of the complete exciton relaxation cascade, which is of paramount importance for the future characterization of non-equilibrium excitonic phases and the efficient design of optoelectronic devices based on two-dimensional materials.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Neutron scattering studies of complex lattice dynamics in energy materials
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Qingyong Ren, Jianli Wang, Bing Li, Jie Ma, Xin Tong
Lattice dynamics play a crucial role in understanding the physical mechanisms of cutting-edge energy materials. Many excellent energy materials have complex multiple-sublattice structures, with intricate lattice dynamics, and the underlying mechanisms are difficult to understand. Neutron scattering technologies, which are known for their high energy and momentum resolution, are powerful tools for simultaneously characterizing material structure and complex lattice dynamics. In recent years, neutron scattering techniques have made significant contributions to the study of energy materials, shedding light on their physical mechanisms. This review article details several neutron scattering techniques commonly used in energy material research, including neutron diffraction, total neutron scattering, quasi-elastic and inelastic neutron scattering. Then, some important research progress made in the field of energy materials in recent years using neutron scattering as the main characterization method is reviewed, including ultra-low lattice thermal conductivity in superionic thermoelectric materials, ion diffusion mechanism of solid-state electrolytes, plastic-crystalline phase transition and configuration entropy changes in barocaloric materials, lattice anharmonicity and charge transport in photovoltaic materials, and first-order magnetic-structural phase transition in magnetocaloric materials. In these complex energy conversion and storage materials, lattice dynamics do not work independently, and their functioning in macroscopic physical properties is always achieved through correlation or mutual coupling with other degrees of freedom, such as sublattices, charge, spin, etc. Through these typical examples, this review paper can provide a reference for further exploring and understanding the energy materials and lattice dynamics.
Materials Science (cond-mat.mtrl-sci)
37 pages, 12 figures
Acta Phys. Sin. 74 (2025) 012801
Photovoltaic Hall Effect by Electric Field-Induced Berry Curvature and Energy Shift
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Yuta Murotani, Tomohiro Fujimoto, Ryusuke Matsunaga
Helicity-dependent photocurrents perpendicular to a bias electric field have attracted considerable attention as an expression of optically controlled Berry curvature in Floquet engineering. More recent studies have revealed a larger contribution by the momentum asymmetry of photocarriers to this photovoltaic Hall effect, although its physical mechanism has not yet been elucidated. In this study, we describe this phenomenon as a circular photogalvanic effect caused by an electric field-induced Berry curvature. The shift vector provides an additional contribution through the energy shift of interband transitions. A resonant enhancement of the transverse photocurrent occurs in GaAs owing to the topological character of the valence band. Our results present a geometric picture of the third-order nonlinear response under light and bias fields, shedding new light on Berry curvature engineering.
Materials Science (cond-mat.mtrl-sci)
7 pages, 4 figures
Validating Griffith fracture propagation in the phase-field approach to fracture: The case of Mode III by means of the trousers test
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
F. Kamarei, E. Breedlove, O. Lopez-Pamies
At present, there is an abundance of results showing that the phase-field approach to fracture in elastic brittle materials – when properly accounting for material strength – describes the \emph{nucleation} of fracture from large pre-existing cracks in a manner that is consistent with the Griffith competition between bulk deformation energy and surface fracture energy. By contrast, results that demonstrate the ability of this approach to describe Griffith fracture \emph{propagation} are scarce and restricted to Mode I. Aimed at addressing this lacuna, the main objective of this paper is to show that the phase-field approach to fracture describes Mode III fracture propagation in a manner that is indeed consistent with the Griffith energy competition. This is accomplished via direct comparisons between phase-field predictions for fracture propagation in the so-called \emph{trousers} \emph{test} and the corresponding results that emerge from the Griffith energy competition. The latter are generated from full-field finite-element solutions that – as an additional critical contribution of this paper – also serve to bring to light the hitherto unexplored limitations of the classical Rivlin-Thomas-Greensmith formulas that are routinely used to analyze the trousers test.
Soft Condensed Matter (cond-mat.soft), Mathematical Physics (math-ph)
A Piezoelectric Molecular Cocrystal with Unconventional $π$-Stacking
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Samuel G. Dunning, Aldo Raeliarijaona, Piotr A. Guńka, Anirudh Hari, Dongzhou Zhang, Ronald E. Cohen, Timothy A. Strobel
We demonstrate the crystallization of a polar octafluoronaphthalene (OFN, \OFN)–phthalazine (Phth, \Phth) cocrystal, formed in a 1:2 ratio by slow evaporation. The crystal structure and vibrational properties of the cocrystal were determined using powder/single-crystal X-ray diffraction (XRD) and Fourier-Transform Infrared (FTIR) spectroscopy, and confirmed with density functional theory (DFT) and density functional perturbation theory (DFPT) calculations. The molecular $ \pi$ -stacking of aromatic rings is unconventional compared with other arene–perfluoroarene cocrystals. Phth molecules are offset and misaligned with respect to the major axis of OFN due to electrostatic repulsion between N and F atoms, enabling overall electric polarization attributed to the dipole moment of Phth. Our calculations show that OFN:2Phth is an insulator with a band gap of $ \sim$ 2.4 eV. The electric polarization was calculated to be 7.1 \muC, while the shear piezoelectric coefficient ($ d_{34}$ ) may be as large as 11.4 pC N$ ^{-1}$ .
Materials Science (cond-mat.mtrl-sci), Soft Condensed Matter (cond-mat.soft)
Above-room-temperature ferromagnetism in large-area epitaxial Fe3GaTe2/graphene van der Waals heterostructures
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Tauqir Shinwari, Kacho Imtiyaz Ali Khan, Hua Lv, Atekelte Abebe Kassa, Frans Munnik, Simon Josephy, Achim Trampert, Victor Ukleev, Chen Luo, Florin Radu, Jens Herfort, Michael Hanke, Joao Marcelo Jordao Lopes
Fe3GaTe2 (FGaT), a two-dimensional (2D) layered ferromagnetic metal, exhibits a high Curie temperature (TC) ~ 360 K along with strong perpendicular magnetic anisotropy (PMA), making it a promising material candidate for next-generation energy-efficient magnetic devices. However, the vast majority of studies on FGaT to date have been limited to millimeter-sized bulk crystals and exfoliated flakes, which are unsuitable for practical applications and integration into device processing. Also, its combination with other 2D materials to form van der Waals heterostructures has only been achieved by flake stacking. Consequently, the controlled large-scale growth of FGaT and related heterostructures remains largely unexplored. In this work, we demonstrate a breakthrough in the high-quality, large-scale growth of epitaxial FGaT thin films on single-crystalline graphene/SiC templates using molecular beam epitaxy. Structural characterization confirms the high crystalline quality of the continuous FGaT/graphene van der Waals heterostructures. Temperature-dependent magnetization and anomalous Hall measurements reveal robust PMA with an enhanced TC well above room temperature, reaching up to 400 K. Furthermore, X-ray absorption and X-ray magnetic circular dichroism spectra provide insight into the spin and orbital magnetic moment contributions, further validating the high TC and robust PMA. These findings are highly significant for the future development of high-performance spintronic devices based on 2D heterostructures, with potential applications in next-generation data storage, logic processing and quantum technologies.
Materials Science (cond-mat.mtrl-sci), Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
Hexagonal ice density dependence on inter atomic distance changes due to nuclear quantum effects
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Lucas T. S. de Miranda, Márcio S. Gomes-Filho, Mariana Rossi, Luana S. Pedroza, Alexandre R. Rocha
Hexagonal ice ($ \rm{I_h}$ ), the most common structure of ice, displays a variety of fascinating properties. Despite major efforts, a theoretical description of all its properties is still lacking. In particular, correctly accounting for its density and interatomic interactions is of utmost importance as a stepping stone for a deeper understanding of other properties. Deep potentials are a recent alternative to investigate the properties of {\iceIH}, which aims to match the accuracy of \textit{ab initio} simulations with the simplicity and scalability of classical molecular dynamics. This becomes particularly significant if one wishes to address nuclear quantum effects. In this work, we use machine learning potentials obtained for different exchange and correlation functionals to simulate the structural and vibrational properties of {\iceIH}. We show that most functionals overestimate the density of ice compared to experimental results. Furthermore, a quantum treatment of the nuclei leads to even further distancing from experiments. We understand this by highlighting how different inter-atomic interactions play a role in obtaining the equilibrium density. In particular, different from water clusters and bulk water, nuclear quantum effects lead to stronger H-bonds in {\iceIH}.
Materials Science (cond-mat.mtrl-sci)
Role of defects in atom probe analysis of sol-gel silica
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Gustav Eriksson, Matteo De Tullio, Francesco Carnovale, Giovanni Novi Inverardi, Tommaso Morresi, Jonathan Houard, Marc Ropitaux, Ivan Blum, Emmanuel Cadel, Gianluca Lattanzi, Mattias Thuvander, Martin Andersson, Mats Hulander, Simone Taioli, Angela Vella
Silica is a suitable material to encapsulate proteins at room temperature, enabling their analysis at the atomic level using laser-assisted atom probe tomography (La- APT). In this study, we show that UV and deep-UV lasers can achieve a high success rate in La-APT of silica in terms of chemical resolution and three-dimensional image volume, with both lasers providing comparable results. Since the La-APT analyses are driven by photon absorption, in order to understand the mechanisms behind the enhanced absorption of UV light, we performed density functional theory calculations to model the electronic and optical properties of amorphous silica matrices generated using a Monte Carlo approach to structural optimisation. In particular, we have investigated the role of various defects introduced during sample preparation, such as substitutional and interstitial carbon, sodium and gallium ions, and hydrogen. Our results show that the presence of defects increases the absorption of silica in the UV and deep-UV range and thus improves the La-APT capabilities of the material. However, due to the low density of free charge carriers resulting from the absorption of laser energy by defects, deviations from the nominal chemical composition and suboptimal chemical resolution may occur, potentially limiting the optimal acquisition of APT mass spectra.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Chemical Physics (physics.chem-ph), Computational Physics (physics.comp-ph), Instrumentation and Detectors (physics.ins-det)
41 pages, 19 figures
Edelstein effect in optically driven monolayer jacutingaite Pt$_2$HgSe$_3$
New Submission | Strongly Correlated Electrons (cond-mat.str-el) | 2025-05-12 20:00 EDT
Nguyen Quang Bau, Ta Thi Tho, Le Thi Thu Phuong, Bui Dinh Hoi
The optical control of spin- and valley-selective gapless states in two-dimensional materials presents new opportunities for next-generation spintronic and valleytronic technologies. In this work, we study monolayer jacutingaite (Pt$ _2$ HgSe$ _3$ ), a quantum spin Hall insulator with strong intrinsic spin-orbit coupling, under irradiation by circularly polarized light. The light-induced Floquet engineering gives rise to tunable topological phases, including transitions to spin- and valley-polarized semimetallic states. To probe these topological transitions, we employ the spin and orbital Edelstein effects – non-equilibrium responses arising from spin-orbit interactions in systems lacking inversion symmetry – without resorting to topological invariants such as Chern numbers. We identify universal signatures of the phase transitions encoded in the Edelstein response: a pronounced discontinuity in the spin Edelstein conductivity and a vanishing orbital Edelstein susceptibility mark the onset of the semimetallic regime. Furthermore, we investigate how the growth and suppression of the spin Edelstein responses across the topological phase transition depend on the interband scattering time. These findings establish the Edelstein effect as a sensitive and experimentally accessible probe of light-induced topological transitions in quantum materials.
Strongly Correlated Electrons (cond-mat.str-el)
8 pages, 4 figures
Control of encounter kinetics by chemically active droplets
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Jacques Fries, Roxanne Berthin, Marie Jardat, Pierre Illien, Vincent Dahirel
Biomolecular condensates play a crucial role in the spatial organization of living matter. These membrane-less organelles, resulting from liquid-liquid phase separation, operate far from thermodynamic equilibrium, with their size and stability influenced by non-equilibrium chemical reactions. While condensates are frequently considered optimized nanoreactors that enhance molecular encounters, their actual impact on reaction kinetics remains unclear due to competing effects such as diffusion hindrance, and random trapping in non-specific condensates. In this study, we develop a microscopic, stochastic model for chemically active droplets, incorporating reaction-driven modulation of protein interactions. Using Brownian dynamics simulations, we investigate how protein interactions and active coupling to a free energy reservoir influence phase separation, molecular transport and reaction kinetics. We demonstrate that the intensity of the chemical drive governs surface dynamics, generating fluxes that modulate bimolecular reaction rates. Comparing active emulsions to homogeneous systems, we reveal that condensates can either accelerate or decelerate molecular encounters. Our findings provide key insights into the role of biomolecular condensates as potential regulators of intracellular reaction kinetics.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Entanglement dynamics and Page curves in random permutation circuits
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
Dávid Szász-Schagrin, Michele Mazzoni, Bruno Bertini, Katja Klobas, Lorenzo Piroli
The characterization of ensembles of many-qubit random states and their realization via quantum circuits are crucial tasks in quantum-information theory. In this work, we study the ensembles generated by quantum circuits that randomly permute the computational basis, thus acting classically on the corresponding states. We focus on the averaged entanglement and present two main results. First, we derive generically tight upper bounds on the entanglement that can be generated by applying permutation circuits to arbitrary initial states. We show that the late-time entanglement Page curves'' are bounded in terms of the initial state participation entropies and its overlap with the maximally antilocalized’’ state. Second, comparing the averaged Rényi-$ 2$ entropies generated by $ (i)$ an infinitely deep random circuit of two-qubit gates and $ (ii)$ global random permutations, we show that the two quantities are different for finite $ N$ but the corresponding Page curves coincide in the thermodynamic limit. We also discuss how these conclusions are modified by additional random phases or considering circuits of $ k$ -local gates with $ k\geq 3$ . Our results are exact and highlight the implications of classical features on entanglement generation in many-body systems.
Statistical Mechanics (cond-mat.stat-mech), Quantum Physics (quant-ph)
7+16 pages, 4 figures
Discovering novel order parameters in the Potts model: A bridge between machine learning and critical phenomena
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
Yi-Lun Du, Nan Su, Konrad Tywoniuk
Machine learning (ML) models trained on Ising spin configurations have demonstrated surprising effectiveness in classifying phases of Potts models, even when processing severely reduced representations that retain only two spin states. To unravel this remarkable capability, we identify a family of novel alternative order parameters for the $ q=3$ and $ q=4$ Potts models on a square lattice, constructed from the occupancies of secondary and minimal spin states rather than the conventional dominant-state order parameter. Through systematic finite-size scaling analyses, we demonstrate that these observables, including a magnetization-like observable derived from a reduced spin representation, accurately capture critical behavior, yielding critical temperatures and exponents consistent with established theoretical predictions and numerical benchmarks. Furthermore, we rigorously establish the fundamental relationships between these alternative order parameters, demonstrating how they collectively encode criticality through different aspects of spin configurations. Our results provide a thermodynamic basis for ML’s success in reduced representations. This work bridges data-driven ML approaches with fundamental statistical mechanics, showing that criticality in Potts systems can be encoded in more compact, non-traditional forms, and opens avenues for discovering analogous order parameters in broader spin systems.
Statistical Mechanics (cond-mat.stat-mech), High Energy Physics - Lattice (hep-lat)
8+3 pages, 3+8 figures, 2 tables
Controlling the morphologies and dynamics in three-dimensional tissues
New Submission | Soft Condensed Matter (cond-mat.soft) | 2025-05-12 20:00 EDT
Rajsekhar Das, Xin Li, Sumit Sinha, D. Thirumalai
A number of factors, such as, cell-cell interactions and self-propulsion of cells driven by cytoskeletal forces determine tissue morphologies and dynamics. To explore the interplay between these factors in controlling the dynamics at the tissue scale, we created a minimal three dimensional model in which short-range repulsive elastic forces account for cell-cell interactions. Self-propulsion is modeled as active uncorrelated random stochastic forces, with strength $ \mu$ , that act on individual cells and is the only source of cell motility. Strikingly, variations in polydispersity in cell sizes ($ \Sigma$ ) and cell elasticity ($ E$ ), results in the formation of a variety of distinct ``phases”, driven entirely by $ \mu$ . At low $ E$ , the tissue behaves like a liquid, at all values of $ \Sigma$ , whereas at high $ E$ and $ \Sigma$ , it has the characteristics of a glass. The tissue crystallizes at low $ \Sigma$ provided $ E$ exceeds a critical value. Over a narrow range of $ E$ and $ \Sigma$ , that lies between the boundaries of the liquid and glass phase, the effective viscosity increases like in a glass as the cell density increases and saturates as the cells are compressed beyond a certain value, creating the viscosity saturation (VS) phase. The VS phase does not form in systems at finite temperature in which the dynamics satisfies the Fluctuation Dissipation Theorem. In the glass phase, the tissue exhibits aging (relaxation times depend on the waiting time) behavior at high $ E$ values. Our findings provide a framework for designing tissues with tunable material properties by controlling the physical characteristics of cells.
Soft Condensed Matter (cond-mat.soft), Biological Physics (physics.bio-ph)
Non-Hermitian Exchange as the Origin of Chirality-Induced Spin Selectivity
New Submission | Mesoscale and Nanoscale Physics (cond-mat.mes-hall) | 2025-05-12 20:00 EDT
Pius M. Theiler, Sander Driessen, Matthew C. Beard
For over two decades, the role of structural chirality in spin polarization has been widely investigated, with implications for the origins of life, catalysis, and quantum phenomena. Yet, it remains unclear whether all chirality-induced spin selectivity (CISS) effects arise from a common mechanism. We show that breaking all mirror symmetries in structurally chiral electron systems enforces a twin-pair electron exchange, inherently violating both parity P and time-reversal T symmetry while preserving combined PT-symmetry of the Hamiltonian. This exchange produces chiral quantum states where electron spin and motion are intrinsically linked, a key feature of CISS. At interfaces, these states drive spin and charge accumulation via spin-momentum locking. Our findings establish a new paradigm connecting quantum statistics, non-Hermitian physics, and spin transport with structural chirality. This framework unifies all observed CISS effects and provides guiding principles for designing chiral materials for spintronic and quantum applications.
Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
12 pages, 4 figures
New Advances in Phonons: From Band Topology to Quasiparticle Chirality
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Tiantian Zhang, Yizhou Liu, Hu Miao, Shuichi Murakami
Phonons, the quantized vibrational modes of a crystal lattice, are ubiquitous quasiparticles in solid-state systems. They play a central role in a wide range of physical phenomena, from thermal transport, as primary carriers of heat in insulators, to their involvement in symmetry-breaking orders such as charge density waves and superconductivity. Traditionally considered as spinless bosons, phonons have recently emerged as a fertile ground for exploring topological physics, spurred by the rapid development of topological band theory initially formulated for fermionic systems. It is now understood that the phonon eigenstates, characterized by their eigenvalues and eigenvectors, can carry nontrivial topological invariants such as Berry curvature and Chern numbers, despite the absence of spin or charge. This new understanding opens up avenues to investigate the interplay between lattice dynamics, topology, and chirality in bosonic systems. In this article, we provide a comprehensive review of recent theoretical and experimental advances in the field of topological and chiral phonons. We begin by introducing the foundational concepts, including the classification of phononic band structures, symmetry-protected topological phases, and the definition of topological invariants in bosonic systems. Special attention is given to the concept of phonon angular momentum and its fundametal connection to Weyl phonons in inversion-symmetry-breaking systems. We then discuss key experimental realizations of topological and chiral phonons across a variety of material platforms. Finally, we outline outstanding challenges and promising directions for future research, such as the role of topology in phonon-mediated quasiparticle interactions and the manipulation of phonon angular momentum in quantum technologies.
Materials Science (cond-mat.mtrl-sci)
Comments are welcomed!
ProME: An Integrated Computational Platform for Material Properties at Extremes and Its Application in Multicomponent Alloy Design
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Xingyu Gao (1), William Yi Wang (2), Xin Chen (1), Xiaoyu Chong (3), Jiawei Xian (1), Fuyang Tian (4), Lifang Wang (1), Huajie Chen (5), Yu Liu (1), Houbing Huang (6), HaiFeng Song (1) ((1) National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing, China, (2) State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, China, (3) Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, China, (4) Institute for Applied Physics, University of Science and Technology Beijing, Beijing, China, (5) School of Mathematical Sciences, Beijing Normal University, Beijing, China, (6) School of Multidisciplinary Science, Beijing Institute of Technology, Beijing, China)
We have built an integrated computational platform for material properties at extreme conditions, ProME (Professional Materials at Extremes) v1.0, which enables integrated calculations for multicomponent alloys, covering high temperatures up to tens of thousands of Kelvin, high pressures up to millions of atmospheres, and high strain rates up to millions per second. A series of software packages have been developed and integrated into ProME v1.0, including ABC (AI-Based Crystal search) for crystal structure search under pressure, SAE (Similar Atomic Environment) for disordered configuration modeling, MFP$ ^2$ (Multiphase Fast Previewer by Mean-Field Potential) for multiphase thermodynamic properties, HTEM (High-throughput Toolkit for Elasticity Modeling) for thermo-elastic properties, TREX (TRansport at Extremes) for electrical and thermal conductivity, Hippos (High plastic phase model software) for phase-field simulation of microstructure evolution under high strain rates, and AutoCalphad for modeling and optimization of phase diagrams with variable compositions. ProME v1.0 has been applied to design the composition of the quaternary alloys Platinum-Iridium-Aluminum-Chromium (Pt-Ir-Al-Cr) for engine nozzles of aerospace attitude-orbit control, achieving high-temperature strength comparable to the currently used Pt-Ir alloys but with significantly reduced costs for raw materials. ProME offers crucial support for advancing both fundamental scientific understanding and industrial innovation in materials research and development.
Materials Science (cond-mat.mtrl-sci), Computational Physics (physics.comp-ph)
Guerra interpolation for inverse freezing
New Submission | Disordered Systems and Neural Networks (cond-mat.dis-nn) | 2025-05-12 20:00 EDT
Linda Albanese, Adriano Barra, Emilio N. M. Cirillo
In these short notes, we adapt and systematically apply Guerra’s interpolation techniques on a class of disordered mean-field spin glasses equipped with crystal fields and multi-value spin variables. These models undergo the phenomenon of inverse melting or inverse freezing. In particular, we focus on the Ghatak-Sherrington model, its extension provided by Katayama and Horiguchi, and the disordered Blume-Emery-Griffiths-Capel model in the mean-field limit, deepened by Crisanti and Leuzzi and by Schupper and Shnerb. Once shown how all these models can be retrieved as particular limits of a unique broader Hamiltonian, we study their free energies. We provide explicit expressions of their annealed and quenched expectations, inspecting the cases of replica symmetry and (first-step) broken replica symmetry. We recover several results previously obtained via heuristic approaches (mainly the replica trick) to prove full agreement with the existing literature. As a sideline, we also inspect the onset of replica symmetry breaking by providing analytically the expression of the de Almeida-Thouless instability line for a replica symmetric description: in this general setting, the latter is new also from a physical viewpoint.
Disordered Systems and Neural Networks (cond-mat.dis-nn), Statistical Mechanics (cond-mat.stat-mech)
Counting observables in stochastic excursions
New Submission | Statistical Mechanics (cond-mat.stat-mech) | 2025-05-12 20:00 EDT
Guilherme Fiusa, Pedro E. Harunari, Abhaya S. Hegde, Gabriel T. Landi
Understanding fluctuations of observables across stochastic trajectories is essential for various fields of research, from quantum thermal machines to biological motors. We introduce the notion of stochastic excursions as a framework to analyze sub-trajectories of processes far from equilibrium. Given a partition of state space in two phases, labeled active and inactive, an excursion starts with a transition into the active phase and ends upon returning to inactivity. By incorporating counting variables, our approach captures finite-time fluctuations and trajectory-level behavior, providing insights on thermodynamic trade-offs between energy expenditure, entropy production and dynamical activity. As our main result, we uncover a fundamental relation between fluctuations of counting observables at the single-excursion level and the steady state noise obtained from full counting statistics. We also show the existence of an exchange-type fluctuation theorem at the level of individual excursions. As an application, we explore how analyzing excursions yields additional insights into the operation of the three-qubit absorption refrigerator.
Statistical Mechanics (cond-mat.stat-mech)
Anomalous spin dynamics after dual optical excitation
New Submission | Materials Science (cond-mat.mtrl-sci) | 2025-05-12 20:00 EDT
Sergii Parchenko, Peter M. Oppeneer, Andreas Scherz
Ultrashort optical pulses are a cornerstone for manipulating electronic and magnetic states in materials on a femtosecond timescale. Conventional models assume that optical excitation primarily modifies the occupation of the electron energy levels without long-lasting altering of the coupling of individual electrons in certain processes. Here, we demonstrate that optical excitation with two femtosecond pulses that come from different directions fundamentally transforms the electron dynamics in copper, affecting the efficiency of angular momentum transfer between electrons and the lattice. Using time-resolved magneto-optical Kerr effect measurements, we reveal a ~2.5. increase in spin imbalance decay time following inverse Faraday effect excitation under dual-pump conditions compared to single-pulse excitation. This observation challenges the prevailing paradigm of ultrafast light-matter interactions, showing that dual optical excitation can transiently modify electron dynamics beyond simple changes in the energy levels occupancy. Our findings open new avenues for controlling quantum states through a dual pump approach, with implications for ultrafast spintronics and the design of novel light-driven states.
Materials Science (cond-mat.mtrl-sci), Applied Physics (physics.app-ph), Optics (physics.optics)