Superconductivity
Superconductor-insulator transitions in infinite-layer nickelates controlled via ${operando}$ monitored reduction
Heng Wang, Haoliang Huang, Wei Lv et al. (+9 more)
Nickelates represent an emerging class of
superconductors that demand innovative approaches for structural and electronic phase modulations. Continuous control over
superconductor-
insulator transition (SIT) in nickelates remains particularly challenging, hindering both fundamental understanding and potential applications. Here, we demonstrate SIT in infinite-layer nickelate
superconductors utilizing multiple techniques, including an ${operando}$ monitored reduction (OMR) method. OMR enables ultrawide-range continuous modulation of the Ni 3${d}$ orbital electron occupancy from ~3${d}^7$ to ~3${d}^9$. The 3${d}$ occupancy is calibrated through systematic synchrotron X-ray absorption (XAS), combined with scanning transmission electron microscopy (STEM) annular bright field (ABF) analysis of oxygen atoms. SIT is further modulated via ionic
liquid gating and
magnetic field. Strikingly different from cuprates, our Nernst effect measurements show that pairing initiates at the onset of the resistive drop. The subsequent emergence of the Meissner effect at zero resistance marks the establishment of global phase coherence. Angle-dependent magnetotransport within the transition temperature regime indicates a mixture of two-dimensional (2D) and three-dimensional (3D) superconducting characters, suggesting the observed SIT deviates from the canonical 2D model. Our results provide a unique perspective on the interplay of structural and electronic phase transitions in the infinite-layer nickelates across the oxygen content-
magnetic field-temperature parameter space.
Read the full abstract ▾
All authors Heng Wang, Haoliang Huang, Wei Lv, Xianfeng Wu, Guangdi Zhou, Zihao Nie, Yueying Li, Cui Ding, Danfeng Li, Hongtao Yuan, Qi-Kun Xue, Zhuoyu Chen
Materials Science
Binding Energies of Charged Particles on Dielectric Surfaces in Liquid Nitrogen
Ashok Timsina and Wolfgang Korsch
A new approach for determining the binding energies of charged particles, such as ions and electrons, on dielectric surfaces in cryogenic
liquids is introduced. The experimental technique outlined in this paper is employed to observe the buildup of charged particles on nonconductive surfaces using the electro-optic Kerr effect. The initial results of binding energy measurements on surfaces of deuterated tetraphenyl butadiene (dTPB)-coated and uncoated polymethyl methacrylate (PMMA) in
liquid nitrogen are presented. Under these conditions, the ions or electrons displayed binding energies of less than 1 meV. Although these findings were obtained in
liquid nitrogen, the methodology is not limited to cryogenic
liquids and is applicable to a wide variety of fluids, with no essential dependence on temperature.
Read the full abstract ▾
Statistical Mechanics
Universal Coarsening and Giant-Cluster Formation in Growing Interfaces
Renan A. L. Almeida, Tiago J. Oliveira, Jeferson J. Arenzon et al. (+1 more)
Clusters formed by fluctuations of two-dimensional (2D) directed interfaces around a threshold level have been extensively studied at
equilibrium and in nonequilibrium steady states, but their coarsening dynamics remain poorly understood. Here, we numerically investigate this unexplored coarsening of clusters in 2D growing interfaces believed to belong to the Kardar-Parisi-Zhang universality class. Using a two-point spatial correlator, we demonstrate statistical time invariance of the evolving configurations and identify scaling forms shared across distinct models. We reveal a pronounced asymmetry in the growth of the largest clusters: one cluster emerges as a
giant structure whose characteristic length exceeds the correlation length. Population-dependent scaling forms for the number densities of cluster areas are uncovered. These findings highlight new universal aspects of growing interfaces and suggest avenues for experimental verification.
Read the full abstract ▾
All authors Renan A. L. Almeida, Tiago J. Oliveira, Jeferson J. Arenzon, Leticia F. Cugliandolo
Mesoscale and Nanoscale Physics
Layer-engineered quantum anomalous Hall effect in twisted rhombohedral graphene
Zhangyuan Chen, Naitian Liu, Jiannan Hua et al. (+13 more)
Realizing programmable topological states in
quantum anomalous
Hall (QAH)
insulators requires the ability to design and dynamically tune their topological invariant, the Chern number C. Here, we report a designer QAH platform based on twisted rhombohedral
graphene family, in which C becomes a programmable and electrically tunable degree of freedom. By engineering the layer configuration in twisted monolayer-rhombohedral N-layer
graphene, denoted as (1+N)L, we realize QAH states with C=N at moire filling v=1, where the layer number N=3,4,5 directly sets the Chern number. Beyond such static layer programming, we demonstrate in-situ electrical control. In a twisted monolayer-trilayer device, the sign of C (chirality) can be switched by electrostatic doping or displacement field. Most strikingly, in twisted Bernal
bilayer-rhombohedral tetralayer
graphene denoted as (2+4)L, we drive a displacement-field-induced topological phase transition between two distinct QAH states with C=3 and C=4 in a single device. Our work establishes a layer-engineered and electrically tunable platform that transitions topological
quantum matter from discovery to design, opening the way toward on-demand engineering of correlated topological states and reconfigurable topological electronics.
Read the full abstract ▾
All authors Zhangyuan Chen, Naitian Liu, Jiannan Hua, Hanxiao Xiang, Wenqiang Zhou, Jing Ding, Xinjie Fang, Linfeng Wu, Le Zhang, Qianmei Chen, Xuanyu Chen, Kenji Watanabe, Takashi Taniguchi, Na Xin, Wei Zhu, Shuigang Xu
Soft Condensed Matter · Cross-listed from math.NA
Numerical solution of Smoluchowski coagulation equation combined with Ostwald ripening
Robert T. Zaks, Sergey A. Matveev, Margarita A. Nikishina et al. (+1 more)
The processes of simultaneous coagulation and Ostwald ripening of particles in the concluding stage of phase transformation are considered. We solve the integro-differential system of Smoluchowski-type kinetic and mass balance equations using a computationally efficient numerical
algorithm based on low-rank
matrices. We compare our numerical solutions for different initial particle-volume distributions with the universal distribution function for combined coagulation and Ostwald ripening. Our calculations confirm the tendency of a particulate ensemble to the universal particle-volume distribution to be approached asymptotically after a sufficiently long time, no matter what the initial particle-volume distribution might be.
Read the full abstract ▾
All authors Robert T. Zaks, Sergey A. Matveev, Margarita A. Nikishina, Dmitri V. Alexandrov
Mesoscale and Nanoscale Physics
Interlayer charge transfer from contact electrification in conducting micro and nanoscale thin film heterostructures
Sandeep Kumar and Ravindra G Bhardwaj
Contact electrification give rise to charge accumulation at the interface when two materials are brought into contact with each other. The charge accumulation at the interface will diffuse to the interior of the conducting material if the dimensions of the contacting conducting material is of the order of an unknown critical length scale. This contact electrification induced interlayer charge transfer will modify the fundamental physical properties of both the contacting materials. This review first discusses the reported experimental evidence of flexoelectricity induced contact electrification and interlayer charge transfer in conducting thin film based
heterostructures. The interlayer charge transfer creates a gradient of charge carrier in both the thin films constituting the
heterostructure and also modifies the electron-electron interactions. Further, the interlayer charge transfer changes the electron-
phonon coupling,
spin-
phonon coupling and magnetoelectronic coupling that give rise to new physical behavior, which did not exist prior to the interlayer charge transfer. The new physical behaviors from interlayer charge transfer and their mechanistic origins are reanalyzed and discussed, which include
spin-
Hall effect of charge carriers, topological
Hall effect of magnetoelectronic electromagnon, inhomogeneous magnetoelectronic multiferroic effect, flexoelectronic proximity effect and topological
spin texture. This review article presents a unified picture of current status and future directions that will provide the scientists a stepping stone for research in the field of flexoelectricity mediated contact electrification and interlayer charge transfer mediated behavior in the micro/nanoscale
heterostructures of the conducting materials.
Read the full abstract ▾
Statistical Mechanics
Component systems: do null models explain everything?
Andrea Mazzolini, Mattia Corigliano, Rossana Droghetti et al. (+2 more)
Component systems - ensembles of realizations built from a shared repertoire of modular parts - are ubiquitous in biological, ecological, technological, and socio-cultural domains. From genomes to texts, cities, and software, these systems exhibit statistical regularities that often meet the "bona fide" requirements of laws in the physical sciences. Here, we argue that the generality and simplicity of those laws are often due to basic combinatorial or sampling constraints, raising the question of whether such patterns are actually revealing system-specific mechanisms and how we might move beyond them. To this end, we first present a unifying mathematical framework, which allows us to compare modular systems in different fields and highlights the common "null" trends as well as the system-specific uniqueness, which, arguably, are signatures of the underlying generative dynamics. Next, we can exploit the framework with statistical mechanics and modern machine-learning tools for a twofold objective. (i) Explaining why the general regularities emerge, highlighting the constraints between them and the general principles at their origins, and (ii) "subtracting" them from data, which will isolate the informative features for inferring hidden system-specific generative processes, mechanistic and causal aspects.
Read the full abstract ▾
All authors Andrea Mazzolini, Mattia Corigliano, Rossana Droghetti, Matteo Osella, Marco Cosentino-Lagomarsino
Materials Science
Correlated domain and crystallographic orientation mapping in uniaxial ferroelectric polycrystals by interferometric vector piezoresponse force microscopy
Ruben Dragland, Jan Schultheiß, Ivan N. Ushakov et al. (+2 more)
Ongoing advances in scanning probe microscopy techniques are continually expanding the possibilities for nanoscale characterization and correlated studies of functional materials. Here, we demonstrate how a recent extension of piezoresponse force microscopy (PFM), known as interferometric vector PFM, can be utilized for simultaneously mapping the local crystallographic orientations and the domain structure of distributed grains in uniaxial ferroelectric polycrystals. By shifting the
laser beam position on the cantilever, direction-dependent piezoresponse signals are acquired analogous to classical vector PFM, but without the need to rotate the sample. Using polycrystalline ErMnO$_{3}$ as a model system, we demonstrate that the reconstructed piezoresponse vectors correlate one-to-one with the crystallographic orientations of the micrometer-sized grains, carrying grain-orientation and domain-related information. We establish a versatile approach for rapid,
multimodal characterization of polycrystalline uniaxial ferroelectrics, enabling automated, high-throughput reconstruction of polarization and grain orientations with nanoscale precision.
Read the full abstract ▾
All authors Ruben Dragland, Jan Schultheiß, Ivan N. Ushakov, Roger Proksch, Dennis Meier
Quantum Gases
Influence of intraspecies interactions on the nucleation and wetting phase diagram in dilute ternary Bose-Einstein condensates
Nguyen Van Thu
Within the framework of Gross-Pitaevskii theory, we investigate the effects of intraspecies interactions on the nucleation transition and the wetting phase diagram of dilute ternary Bose-Einstein condensate in the regime of strong segregation between two components. The analyses are carried out using both the analytical double-parabola approximation (DPA) and numerical computations. Our results show that the DPA provides a reliable approximation for describing the nucleation transition. For the wetting phase diagram, we find that the DPA is in excellent agreement with numerical results in symmetric systems, particularly in the completely symmetric case, whereas it fails to provide an adequate description for asymmetric systems.
Read the full abstract ▾
Materials Science
Grain-Growth Stagnation from Vacancy-Diffusion-Limited Disconnection Climb
Maik Punke, Abel H. G. Milor and Marco Salvalaglio
Grain growth in polycrystals typically stagnates at long times. We identify disconnection climb, limited by vacancy
diffusion, as a fundamental microscopic mechanism underlying this behavior. Using a phase-field
crystal framework extended to model vacancy
diffusion, we resolve grain-boundary migration on diffusive time scales and show that disconnection climb rates correlate with the characteristic grain size at which growth arrests. These results link vacancy transport, disconnection dynamics, and microstructural
evolution, establishing vacancy
diffusion as a key governing factor.
Read the full abstract ▾
Materials Science
Direct probing the quantum geometric tensor for bosonic collective excitations
Chi Wu, Takashi Oka, Shuichi Murakami et al. (+1 more)
The
quantum geometric tensor (QGT), whose real and imaginary parts define the
quantum metric and Berry
curvature, encodes the intrinsic geometry of
quantum states. While electronic QGT has recently become experimentally accessible and linked to diverse physical phenomena, its bosonic counterpart remains largely unexplored. Here we show that the dynamical structure factor encodes the momentum-space structure of bosonic wave functions and thereby provides direct access to the full bosonic QGT throughout the Brillouin zone. Applying this framework, we uncover clear
geometric signatures in the twofold quadrupole-Weyl
phonon of BaPtGe and the nodal-line
magnon in Gd, and further generalize the formalism to multiband systems. Our results establish a general route to measuring (non-)Abelian
quantum geometry in bosonic systems, a crucial step toward elucidating its impact on condensed matter phenomena.
Read the full abstract ▾
All authors Chi Wu, Takashi Oka, Shuichi Murakami, Tiantian Zhang
Materials Science
Dynamic Multiband Microscopy: A Universal Paradigm for Quantitative Nanoscale Metrology
Boris N. Slautin, Alwikh Rohi, Sanjay Mathur et al. (+4 more)
Scanning Probe Microscopy (SPM) is the primary tool for exploring nanoscale functionality, yet standard single-frequency operation is fundamentally limited, because the dynamic tip-sample interaction is mathematically underdetermined. While advanced methods such as Dual Amplitude Resonance Tracking (DART) and Band Excitation (BE) address this by tracking resonance, they face critical limitations: DART suffers from feedback instability on complex topographies, while Band Excitation is constrained by severe trade-offs between spectral resolution and acquisition speed. Here, we introduce Dynamic Multiband Microscopy (DMM), a general framework that bridges these gaps by combining multifrequency excitation with continuous frequency sweeping. We implement this within an automated experimental workflow that autonomously identifies and targets measurement points of interest. In combination with quantitative interferometric detection, this approach brings SPM to the fundamental limits of noise and spectral sensitivity. Validated on ferroelectric nanofibers, this platform enables simultaneous, crosstalk-free 3D polarization mapping, establishing a universal framework for autonomous, high-fidelity nanoscale metrology.
Read the full abstract ▾
All authors Boris N. Slautin, Alwikh Rohi, Sanjay Mathur, Arun Ichangi, Sergei V. Kalinin, Doru C. Lupascu, Vladimir V. Shvartsman
Statistical Mechanics · Cross-listed from physics.soc-ph
Generating consensus and dissent on massive discussion platforms with a semantic-vector model
A. Ferrer, D. Muñoz-Jordán, A. Rivero et al. (+3 more)
Reaching consensus on massive discussion networks is critical for reducing noise and achieving optimal collective outcomes. However, the natural tendency of humans to preserve their initial ideas constrains the emergence of global solutions. To address this, Collective Intelligence (CI) platforms facilitate the discovery of globally superior solutions. We introduce a dynamical system based on the standard $O(N)$ model to drive the aggregation of semantically similar ideas. The system consists of users represented as nodes in a $d=2$
lattice with nearest-neighbor interactions, where their ideas are represented by semantic vectors computed with a pretrained
embedding model. We analyze the system's
equilibrium states as a function of the coupling parameter $\beta$. Our results show that $\beta > 0$ drives the system toward a
ferromagnetic-like phase (global consensus), while $\beta < 0$ induces an
antiferromagnetic-like state (maximum dissent), where users maximize semantic distance from their neighbors. This framework offers a controllable method for managing the tradeoff between cohesion and diversity in CI platforms.
Read the full abstract ▾
All authors A. Ferrer, D. Muñoz-Jordán, A. Rivero, A. Tarancón, C. Tarancón, D. Yllanes
Strongly Correlated Electrons
Alternative $\nu+\nu$-picture of bosonic fractional Chern insulators at high filling factors in multiple flat-band systems
Licheng Wang, Dong-Hao Guan, Ai-Lei He et al. (+2 more)
Most fractional
quantum Hall states have been traditionally identified within a single energy band, such as the lowest Landau level or topological flat band. As more particles are introduced, they inevitably populate higher energy bands. Whether the inclusion of multiple topological bands leads to new physics remains an open question. Here, we propose a universal picture applicable at higher filling factors $\nu \geq 1$ in bosonic systems: the occupied bands tend to coalesce into an effective single topological band characterized by a total Chern number $\vert C\vert$, the sum of the Chern number of all occupied lower topological flat bands. Using a Kekulé
lattice model with two lower flat bands featuring a total Chern number $C=1$, regardless of their specific configurations, we identify the emergence of a $\frac{1}{2}$ fractional Chern
insulator (FCI) state at integer filling factor $\nu=1$, followed by the Jain sequence states $\frac{2}{3}$ and $\frac{3}{4}$ at filling $\nu=\frac{4}{3}$ and $\frac{6}{4}$. That is a $\nu+\nu$ picture, rather than the generally expected $1+\nu^{\prime}$ picture, where $\nu^{\prime}$ is the permitted FCI filling factor in the single second topological flat band. Our findings deepen the understanding of FCI states and open avenues for discovering exotic fractional topological phases in multiband systems.
Read the full abstract ▾
All authors Licheng Wang, Dong-Hao Guan, Ai-Lei He, Shun-Li Yu, Yuan Zhou
Materials Science
Determinants of Self-Interstitial Energetics in Refractory High-Entropy Alloys
Zichen Zhang, Zhiling Luo, Wang Gao et al. (+1 more)
Self-interstitials play a central role in governing the mechanical and anti-irradiation properties of refractory high-
entropy alloys (RHEAs), however, the prediction of interstitial formation energies (Ef) is formidable due to the chemically complex environments in RHEAs. Herein, we develop a framework based on the tight-binding model to quantify the effects of complex alloying and
lattice distortion on Ef. Our scheme reveals that Ef is jointly determined by the average d-band center of RHEAs and the d-band width of interstitial sites. Notably, the d-band width mainly depends on the interatomic hopping
matrix and atomic size-determined coordination number, which together make the metallic bonding around interstitials in RHEAs resemble the distance-dependence law of van der Waals forces. By capturing d-band coupling character, our descriptor describes both interstitial configurations within a universal framework. Our model reveals a new physical picture of interstitial formation, providing a useful tool for the design of high-performance RHEAs.
Read the full abstract ▾
All authors Zichen Zhang, Zhiling Luo, Wang Gao, Qing Jiang
Materials Science
Janus MoSSe/WSSe Heterobilayers as Selective Photocatalysts for Water Splitting
Mostafa Torkashvand, Saeedeh Sarabadani Tafreshi, Caterina Cocchi et al. (+1 more)
Identifying materials that simultaneously straddle the water redox potentials and possess an intrinsic electric field is crucial for achieving high
solar-to-hydrogen (STH) efficiency. Using state-of-the-art first-principles calculations, including a range-separated hybrid functional and
spin-orbit coupling, we investigate MoXY/WXY (X, Y = S, Se) Janus
bilayers for overall water splitting. We find a critical competition between the metal-to-metal chemical potential difference and the intrinsic dipoles at the interface between the Janus monolayers. We find that the Se-Se interfaced heterobilayer is intrinsically capable of driving water splitting, while its S-S counterpart can meet the redox requirements through pH modulation. For both configurations, a remarkable STH efficiency of 17.1% is anticipated. Furthermore, we predict a threshold of 1.0 eV for the built-in potential gradient to govern the transition from overall water splitting to band-edge pinning. Compared to homobilayers, heterobilayers benefit from the reciprocity between layer-specific dipoles and the Mo/W chemical potential difference, which promotes spatial separation and suppresses recombination, overall enhancing hydrogen production. Our results establish specific electronic descriptors for Janus
heterostructures, providing a rational design rule for maximizing
solar-driven hydrogen production in asymmetric two-dimensional materials.
Read the full abstract ▾
All authors Mostafa Torkashvand, Saeedeh Sarabadani Tafreshi, Caterina Cocchi, Surender Kumar
Strongly Correlated Electrons
Correlation-driven branch in doped excitonic insulators
Tatsuya Kaneko, Ryota Ueda and Satoshi Ejima
We investigate the spectral properties of doped one-dimensional excitonic
insulators. Employing
matrix-product-state-based methods, we compute the single-particle spectrum and optical conductivity in a correlated two-band model. Our numerical calculation reveals the emergence of a correlation-driven in-gap branch in the doped state. The origin of the in-gap branch is examined by decomposing the propagation dynamics of a single particle, elucidating that the doping-induced branch is associated with excitonic correlations. Our demonstrations suggest that the doping-induced branch can serve as an indicator of electron-hole correlations.
Read the full abstract ▾
Soft Condensed Matter
Unraveling the Mechanisms of Ultrasound-Induced Mechanical Degradation of Microgels: Effects of Mechanoresponsive Crosslinks, Softness, and Core-Shell Architecture
Alexander V. Petrunin, Susanne Braun, Felix J. Byn et al. (+6 more)
Ultrasound-induced degradation of soft polymeric colloids, like microgels, as well as a controlled drug release enabled by mechanoresponsive bonds, has recently attracted considerable
attention. However, most examples in the literature focus primarily on the applications rather than examining the underlying mechanisms of the structural changes occurring in microgels due to cavitation - changes that are crucial for developing effective drug delivery systems. In this work, we provide a comprehensive view on how microgel structure governs the susceptibility to rupture and mass loss upon cavitation, investigating both conventional microgels containing mechanoresponsive disulfide bonds and more complex asymmetrically crosslinked core-shell microgels. By combining dynamic and static light scattering, small-angle X-ray scattering, and atomic force microscopy, we demonstrate that an interplay between mechanoresponsive crosslinks and the swelling degree determines the microgels susceptibility to ultrasound-induced damage. Our findings indicate that local stress from cavitation bubbles varies strongly within the microgel dispersion. The majority of microgels undergo gradual erosion at their periphery, resulting in smaller yet structurally intact particles over time, observable by light scattering and AFM. In contrast, microgels closer to a cavitation bubble can experience partial rupture or completely disintegrate, producing smaller, more polydisperse fragments, which contributes substantially to the overall mass loss observed. In the core-shell microgels with different crosslinkers in the core and shell, degradation occurs nearly uniformly across both regions, instead of selectively targeting the weaker part. These observations highlight the complexity of the degradation dynamics as well as the similarity to processes seen in linear
polymers and bulk hydrogels.
Read the full abstract ▾
All authors Alexander V. Petrunin, Susanne Braun, Felix J. Byn, Indré Milvydaité, Timon Kratzenberg, Pablo Mota-Santiago, Andrea Scotti, Andrij Pich, Walter Richtering
Strongly Correlated Electrons
To infinity and back – $1/N$ graph expansions of light-matter systems
Andreas Schellenberger and Kai P. Schmidt
We present a method for performing a full graph expansion for light-matter systems, utilizing the linked-cluster
theorem. This method enables us to explore $1/N$ corrections to the thermodynamic limit $N\to \infty$ in the number of particles, giving us access to the mesoscopic regime. While this regime is yet largely unexplored due to the challenges of studying it with established approaches, it incorporates intriguing features, such as
entanglement between light and matter that vanishes in the thermodynamic limit. As a representative application, we calculate physical quantities of the low-energy regime for the paradigmatic Dicke-Ising chain in the paramagnetic normal phase by accompanying the graph expansion with both exact diagonalization (NLCE) and perturbation theory (pcst++), benchmarking our approach against other techniques. We investigate the ground-state energy density and
photon density, showing a smooth transition from the microscopic to the macroscopic regime up to the thermodynamic limit. Around the
quantum critical point, we extract the $1/N$ corrections to the ground-state energy density to obtain the critical point and critical exponent using extrapolation techniques.
Read the full abstract ▾
Mesoscale and Nanoscale Physics
Confinement-Tunable Synthetic Gauge Fields and Floquet Topological Phenomena in a Driven Quantum Wire Qubit
Dongmo Tedo Lynsia Saychele, Feulefack Ornela Claire, Danga Jeremie Edmond et al. (+6 more)
Theoretical analysis indicates that a
spin qubit in a
parabolic quantum wire, when driven by a bichromatic field, generates a confinement-tunable non-Abelian synthetic gauge field that gives rise to novel Floquet topological phenomena. In the low-confinement regime, the system exhibits topological Landau-Zener (LZ) transitions,
chiral Landau-Zener-St$\ddot{u}$ckelberg-Majorana (LZSM) interference, and non-Abelian
geometric phases around diabolical points. These features enable holonomic
quantum computation, as well as unconventional Floquet Bloch oscillations and fractal spectra. In contrast, in the strong confinement regime, narrow avoided crossings significantly suppress cross-coupling, thereby insulating the
qubit from multi-
photon LZSM interference. Quantitative Floquet-Lindblad analysis shows that the optimized gate times, determined by the biharmonic driving period and non-Abelian parameter-space loops, are sufficiently short to surpass primary environmental decoherence channels. When applied to high-mobility $\text{GaAs/AlGaAs}$ core-shell nanowires, this approach converts spatial drives into robust non-Abelian gauge fields, positioning
quantum wire systems as a versatile and scalable platform for fault-tolerant
quantum information processing.
Read the full abstract ▾
All authors Dongmo Tedo Lynsia Saychele, Feulefack Ornela Claire, Danga Jeremie Edmond, Keumo Tsiaze Roger Magloire, Fridolin Melong, Kenfack-Sadem Christian, Fotue Alain Jerve, Mahouton Norbert Hounkonnou, Lukong Cornelius Fai
Materials Science · Cross-listed from physics.atm-clus
Interpretable, Physics-Informed Learning Reveals Sulfur Adsorption and Poisoning Mechanisms in 13-Atom Icosahedra Nanoclusters
Raiane Ferreira Monteiro, João Marcos T. Palheta, Tulio Gnoatto Grison et al. (+7 more)
Transition-metal nanoclusters exhibit structural and electronic properties that depend on their size, often making them superior to bulk materials for heterogeneous catalysis. However, their performance can be limited by sulfur poisoning. Here, we use dispersion-corrected density functional theory (DFT) and physics-informed machine learning to map how atomic sulfur adsorbs and causes poisoning on 13-atom icosahedral clusters from 30 different transition metals (3$d$ to 5$d$). We measure which sites sulfur prefers to adsorb to, the thermodynamics and energy breakdown, changes in structure, such as bond lengths and coordination, and electronic properties, such as $\varepsilon_d$, the HOMO-LUMO gap, and charge transfer. Vibrational analysis reveals true energy minima and provides ZPE-based descriptors that reflect the
lattice stiffening upon sulfur adsorption. For most metals, the metal-sulfur interaction mainly determines adsorption energy. At the same time, distortion penalties are usually moderate but can be significant for a few metals, suggesting these are more likely to restructure when sulfur is adsorbed. Using unsupervised k-means clustering, we identify periodic trends and group metals based on their adsorption responses. Supervised regression models with leave-one-feature-out analysis identify the descriptors that best predict adsorption for new samples. Our results highlight the isoelectronic triad \ce{Ti}, \ce{Zr}, and \ce{Hf} as a balanced group that combines strong sulfur binding with minimal structural change. Additional DFT calculations for \ce{SO2} adsorption reveal strong binding and a clear tendency toward dissociation on these clusters, linking electronic states,
lattice response, and poisoning strength. These findings offer data-driven guidelines for designing sulfur-tolerant nanocatalysts at the subnanometer scale.
Read the full abstract ▾
All authors Raiane Ferreira Monteiro, João Marcos T. Palheta, Tulio Gnoatto Grison, Octávio Rodrigues Filho, Renato Luis Tame Parreira, Diego Guedes-Sobrinho, Celso R. C. Rêgo, Alexandre C. Dias, Krys Elly de Araújo Batista, Maurício J. Piotrowski
Materials Science
Nanoparticle Self-assembly Assisted by Polymers: The Role of Shear Stress in the Nanoparticle Arrangement of Langmuir and Langmuir-Blodgett Films
Beatriz Martín-García and M. Mercedes Velázquez
We propose to use the self-assembly ability of a block copolymer combined with compression-expansion cycles to obtain CdSe
quantum dots (QDs) structures of different morphology. The methodology proposed consists in transferring onto mica mixed Langmuir monolayers of QDs and the
polymer poly (styrene-co-maleic anhydride) partial 2 buthoxy ethyl ester cumene terminated, PS-MA-BEE, previously sheared by 50 compression-expansion cycles. Results indicate that the shear stress takes out nanoparticles at the air-water interface from metastable states and promoted a new
equilibrium state of the Langmuir monolayer, then it was transferred onto mica by the Langmuir-Blodgett (LB) methodology and the morphology of the LB films was analyzed by Atomic Force Microscopy and Transmission Electron Microscopy measurements. Our results show that when the amplitude strain increases the QDs domain size decreases and the LB film becomes more ordered. The dynamic of the monolayer relaxation after cycling involves at least three timescales which are related to the damping of surface fluctuation, raft rearrangement and component movements inside each raft. Brewster Angle Microscopy allowed visualizing in situ the raft rearrangement at the air-water interface.
Read the full abstract ▾
Quantum Gases · Cross-listed from nucl-th
Comparative study of quartet superfluid state: Quartet Bardeen-Cooper-Schrieffer theory and generalized Nambu-Gor'kov formalism
Yixin Guo, Hiroyuki Tajima and Haozhao Liang
We theoretically investigate a quartet superfluid state in fermionic matter by using the quartet Bardeen-Cooper-Schrieffer (BCS) variational theory and the Green's function method. We demonstrate that the quartet BCS theory with the multiple-infinite-product ansatz successfully reproduces an exact four-body result in a one-dimensional four-component
Fermi gas at the dilute limit, in contrast to the single-infinite-product ansatz. To see the validity of the quartet BCS state, we derive the self-consistent equation for the quartet superfluid order parameter within the generalized imaginary-time Nambu-Gor'kov formalism, which is found to be consistent with the quartet BCS variational equation. Moreover, by numerically computing the momentum-resolved single-particle spectral function in a one-dimensional system, we discuss how the single-particle spectra evolve with increasing the strength of the four-body cluster formation. We show that a coherent BCS-like quasiparticle branch on the weak-coupling side evolves into a strongly damped, continuum-dominated spectrum in the strong-coupling side, while nonzero quartet superfluid order parameter persists throughout the crossover regime. Our results would be useful for understanding beyond-BCS pairing effects and four-body cluster formations in fermionic systems in an interdisciplinary way.
Read the full abstract ▾
Strongly Correlated Electrons
Quantum simulation of general spin-1/2 Hamiltonians with parity-violating fermionic Gaussian states
Michael Kaicher, Joseph Vovrosh, Alexandre Dauphin et al. (+1 more)
We introduce equations of motion for a parity-violating fermionic mean-field theory (PV-FMFT): a numerically efficient fermionic mean-field theory based on parity-violating fermionic Gaussian states (PV-FGS). This work provides explicit equations of motion for studying the real- and imaginary-time
evolution of
spin-1/2
Hamiltonians with arbitrary geometries and interactions. We extend previous formulations of parity-preserving fermionic mean-field theory (PP-FMFT) by including fermionic displacement operators in the variational Ansatz. Unlike PP-FMFT, PV-FMFT can be applied to general
spin-1/2
Hamiltonians, describe quenches from arbitrary initial
spin-1/2 product states, and compute local and non-local observables in a straight-forward manner at the same modest computational cost as PP-FMFT – scaling as $O(N^3)$ in the worst case for a system of $N$
spins or fermionic modes. We demonstrate that PV-FMFT can exactly capture the imaginary- and real-time dynamics of non-interacting
spin-1/2
Hamiltonians. We then study the post quench-dynamics of the one- and two-dimensional Ising model in presence of longitudinal and transversal fields with PV-FMFT and compute the single site magnetization and correlation functions, and compare them against results from other state-of-the-art numerical approaches. In two-dimensional
spin systems, we show that the employed
spin-to-
fermion mapping can break rotational
symmetry within the PV-FMFT description, and we discuss the resulting consequences for the calculated correlation functions. Our work introduces PV-FMFT as a
benchmark for other numerical techniques and
quantum simulators, and it outlines both its capabilities and its limitations.
Read the full abstract ▾
All authors Michael Kaicher, Joseph Vovrosh, Alexandre Dauphin, Simon B. Jäger
Materials Science
Influence of Ru content on electrocatalytic activity and defect formation of Au-Pd-Pt-Ru compositionally complex solid solution thin films
Miran Joo, Huixin Xiu, Sabrina Baha et al. (+8 more)
Compositionally complex solid solutions (CCSSs) consist of a randomly mixed single phase with the potential to enhance electrocatalytic activity through their polyelemental surface atom arrangements. However, microstructural complexity originating from multiple principal elements influences local structure, chemistry, and
lattice strain, which might also affect electrocatalytic activity. Here, we investigate the effect of Ru content on electrochemistry and defect formation in Au-Pd-Pt-Ru CCSS thin films. Such defects could provide active sites when terminating at the CCSS surface or modify surface composition through preferential segregation. A thin-film material library covering a wide composition range was fabricated by room-temperature combinatorial co-sputtering. High-throughput compositional, structural and functional characterization, including electron microscopy equipped with energy dispersive X-ray spectroscopy, X-ray diffraction, and electrochemical screening, were used to correlate composition and microstructural features with catalytic activity. Three representative compositions selected from the library - Au68Pd13Pt15Ru4, Au27Pd24Pt23Ru26, and Au9Pd21Pt18Ru52 - were examined in detail. The three samples exhibit face-centered cubic structures, with
lattice contraction occurring with increasing Ru content. In addition, with increasing Ru content, a transition from a high density of nanotwins to high-density, atomic-layer stacking faults was observed. Moreover, the hydrogen
evolution reaction activity improves with higher Ru content. Atom probe
tomography reveals local compositional fluctuations, including element-specific enrichment and depletion at grain boundaries. The findings provide a new insight into surface atom arrangement design in the CCSS electrocatalysts with enhanced performance.
Read the full abstract ▾
All authors Miran Joo, Huixin Xiu, Sabrina Baha, Ridha Zerdoumi, Ningyan Cheng, Christoph Somsen, Yujiao Li, Aleksander Kostka, Wolfgang Schuhmann, Alfred Ludwig, Christina Scheu
Strongly Correlated Electrons
Entanglement entropy and disorder operator at kagome deconfined quantum criticality
Yan-Cheng Wang, Yan Zheng and Xue-Feng Zhang
We investigate the deconfined
quantum critical point (DQCP) candidate in the extended hard-core Bose-Hubbard model on the kagome
lattice, employing
quantum Monte Carlo simulations to study the
entanglement entropy and the $U(1)$ disorder operator. In stark contrast to findings in $J$-$Q$ models and other candidates, the universal logarithmic correction coefficients for both quantities are found to be {positive}, consistent with a
unitary conformal field theory (CFT). Crucially, the current central charge $C_J$, extracted from the small-angle behavior of the disorder operator, is enhanced by a factor of approximately {4/3} compared to that of the conventional 3D $O(2)$ Wilson-Fisher fixed point. This enhancement {implies} a consistent explanation in the recently observed low-energy excitation spectrum at this DQCP, which features {two distinct linearly dispersing modes} with a velocity ratio of approximately three. Our results provide evidence that this
quantum phase transition constitutes a genuine DQCP, characterized by coexisting fractionalized excitations that collectively modify its critical properties.
Read the full abstract ▾
Strongly Correlated Electrons
On the Optimal Layout of Two-Dimensional Lattices for Density Matrix Renormalization Group
A. Scardicchio
For
quantum spin models defined on a two-dimensional
lattice, we look for the best numbering of the
lattice sites (a layout) that, at fixed bond dimension and other parameters of the density
matrix renormalization group (DMRG)
algorithm, gives the lowest value of the variational energy, maximum
entropy and truncation error. We consider the
conjecture that the optimal layout is a
Hamiltonian path, and that it optimizes a simply computable
geometric cost function. Finding the minimum of such a function, which is a variant of the minimum linear arrangement problem, provides the DMRG with an efficient layout of the
lattice and improves both accuracy and convergence time. We present applications to the
antiferromagnetic and
spin glass
spin-1/2 models on the square and triangular
lattices.
Read the full abstract ▾
Disordered Systems and Neural Networks
Topological Anderson insulator and reentrant topological transitions in a mosaic trimer lattice
Xiatao Wang, Li Wang and Shu Chen
We study the topological properties of a one-dimensional quasiperiodic-potential-modulated mosaic trimer
lattice. To begin with, we first investigate the topological properties of the model in the clean limit free of quasiperiodic disorder based on analytical derivation and numerical calculations of the Zak phase $Z$ and the polarization $P$. Two nontrivial topological phases corresponding to the $1/3$ filling and $2/3$ filling, respectively, are revealed. Then we incorporate the mosaic modulation and investigate the influence of quasiperiodic disorder on the two existing topological phases. Interestingly, it turns out that quasiperiodic disorder gives rise to multiple distinct effects for different fillings. At $2/3$ filling, the topological phase is significantly enhanced by the quasiperiodic disorder and topological Anderson
insulator emerges. Based on the calculations of polarization and energy gap, we explicitly present corresponding topological phase diagram in the $\lambda-J$ plane. While for the $1/3$ filling case, % the topological phase is dramatically suppressed by the same quasiperiodic disorder. the quasiperiodic disorder dramatically compresses the topological phase, and strikingly, further induces the emergence of reentrant topological phase transitions instead. Furthermore, we verify the topological phase diagrams by computing the many-body ground state fidelity susceptibility for both the $1/3$ filling and $2/3$ filling cases. Our work exemplifies the diverse roles of quasiperiodic disorder in the modulation of topological properties, and will further inspire more research on the competitive and cooperative interplay between topological properties and quasiperiodic disorder.
Read the full abstract ▾
Strongly Correlated Electrons
Large magneto-optical Kerr effect induced by collinear antiferromagnetic order
H. Yoshimochi, K. Yoshida, R. Oiwa et al. (+6 more)
In modern technology, the optical readout of
magnetic information is conventionally achieved by the magneto-optical Kerr effect, i.e., the polarization rotation of reflected light. The Kerr rotation is sensitive to time-reversal
symmetry breaking and generally proportional to magnetization, enabling optical readout of the up and down
spin states in ferromagnets. By contrast, antiferromagnets with a collinear antiparallel
spin arrangement have long been considered inactive to such magneto-optical responses, because of Tt-
symmetry (time-reversal T followed by translation t
symmetry) and lack of macroscopic magnetization. Here, we report the observation of
giant magneto-optical Kerr effect in a room-temperature
antiferromagnetic insulator alpha-Fe2O3. In this compound, the up-down and down-up
spin states induce the opposite sign of spontaneous Kerr effect, whose Kerr rotation angle turned out to be exceptionally large (~ 80 mdeg, comparable to typical ferromagnets). Our first-principles calculations successfully reproduce both the absolute magnitude and spectral shape of the Kerr rotation and ellipticity with remarkable accuracy, which unambiguously proves that it originates from a Tt-
symmetry-broken collinear
antiferromagnetic order, rather than magnetization. This compound hosts temperature-dependent transition between easy-plane and easy-axis
antiferromagnetic states, and their contrasting behaviors are also investigated in detail. The present results demonstrate that even a simple collinear
antiferromagnetic order can induce a
giant magneto-optical Kerr effect, and highlight Tt-
symmetry-broken antiferromagnets as a promising material platform for highly sensitive optical detection of up-down and down-up
spin states.
Read the full abstract ▾
All authors H. Yoshimochi, K. Yoshida, R. Oiwa, T. Nomoto, N. D. Khanh, A. Kitaori, R. Takagi, R. Arita, S. Seki
Materials Science
Near-atomic investigation on the elemental redistribution during co-precipitation of nano-sized kappa phase and B2 phase in an Al-alloyed lightweight steel
Bowen Zou, Yixu Wang, Xiao Shen et al. (+4 more)
In the present study, correlative transmission Kikuchi diffraction transmission electron microscopy (TKD-TEM) measurements, atom probe
tomography (APT), and density functional theory (DFT) calculations are used to reveal the elemental redistribution during co-precipitation of nanosized kappa and B2 phases in an FCC
matrix of an Al alloyed Fe-10Al-7Mn-6Ni-1C (wt.%) steel. Upon ageing at 800 C for 15 min, two co-nanoprecipitation modes are observed: B2 forming together with kappa and B2 forming separately from kappa in the FCC
matrix. APT reveals that the B2 precipitate next to kappa (referred to as B2I) is close to an FeAl type phase, while the isolated B2 precipitate (referred to as B2II) is close to a NiAl type phase. The kappa precipitates maintain a nearly constant Al content of approximately 18.4 at.% regardless of their precipitation position. DFT confirms that kappa may accommodate limited Ni substitution at Fe sites without losing structural stability, and that Fe Ni atomic exchange between kappa and B2 is thermodynamically favorable at 800 C. This exchange drives the B2 phase to evolve from a NiAl type towards an FeAl type, improving the stability of both phases during co-precipitation. These results provide understanding of kappa B2 interactions and offer insights for designing nanosized intermetallic strengthened microstructures in Al alloyed lightweight steels.
Read the full abstract ▾
All authors Bowen Zou, Yixu Wang, Xiao Shen, Philipp Krooss, Thomas Niendorf, Richard Dronskowski, Wenwen Song