Found 60 papers in cond-mat

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

Bridging the small and large in twisted transition metal dicalcogenide homobilayers: a tight binding model capturing orbital interference and topology across a wide range of twist angles
Valentin Cr\'epel, Andrew Millis
arXiv:2403.15546v1 Announce Type: new Abstract: Many of the important phases observed in twisted transition metal dichalcogenide homobilayers are driven by short-range interactions, which should be captured by a local tight binding description since no Wannier obstruction exists for these systems. Yet, published theoretical descriptions have been mutually inconsistent, with honeycomb lattice tight binding models adopted for some twist angles, triangular lattice models adopted for others, and with tight binding models forsaken in favor of band projected continuum models in many numerical simulations. Here, we derive and study a minimal model containing both honeycomb orbitals and a triangular site that represents the band physics across a wide range of twist angles. The model provides a natural basis to study the interplay of interaction and topology in these heterostructures. It elucidates from generic features of the bilayer the sequence of Chern numbers occurring as twist angle is varied, and the microscopic origin of the magic angle at which flat-band physics occurs. At integer filling, the model successfully captures the Chern ferromagnetic and van-Hove driven antiferromagnetic insulators experimentally observed for small and large angles, respectively, and allows a straightforward calculation of the magneto-electric properties of the system.

Fast real-time arbitrary waveform generation using graphic processing units
Juntian Tu, Sarthak Subhankar
arXiv:2403.15582v1 Announce Type: new Abstract: Real-time Arbitrary Waveform Generation (AWG) is essential in various engineering and research applications, and often requires complex bespoke hardware and software. This paper introduces an AWG framework using an NVIDIA Graphics Processing Unit (GPU) and a commercially available high-speed Digital-to-Analog Converter (DAC) card, both running on a desktop personal computer (PC). The GPU accelerates the "embarrassingly" data parallel additive waveform synthesis framework for AWG, and the DAC reconstructs the generated waveform in the analog domain at high speed. The AWG framework is programmed using the developer-friendly Compute Unified Device Architecture (CUDA) runtime application programming interface from NVIDIA and is readily customizable, and scalable with additional parallel hardware. We present and characterize two different pathways for computing modulated radio-frequency (rf) waveforms: one pathway offers high-complexity simultaneous chirping of 1000 individual Nyquist-limited single-frequency tones for 35 ms at a sampling rate of 560 MB/s, and the other pathway allows simultaneous continuous chirping of 194 individual Nyquist-limited single-frequency tones at 100 MB/s, or 20 individual tones at 560 MB/s. This AWG framework is designed for fast on-the-fly rearrangement of a large stochastically-loaded optical tweezer array of single atoms or molecules into a defect-free array needed for quantum simulation and quantum computation applications.

Nanoscale Imaging of Phonons and Reconfiguration in Topologically-Engineered, Self-Assembled Nanoparticle Lattice
Chang Qian, Ethan Stanifer, Zhan Ma, Binbin Luo, Chang Liu, Lehan Yao, Wenxiao Pan, Xiaoming Mao, Qian Chen
arXiv:2403.15627v1 Announce Type: new Abstract: Topologically-engineered mechanical frames are important model constructs for architecture, machine mechanisms, and metamaterials. Despite significant advances in macroscopically fashioned frames, realization and phonon imaging of nanoframes have remained challenging. Here we extend for the first time the principles of topologically-engineered mechanical frames to lattices self-assembled from nanoparticles. Liquid-phase transmission electron microscopy images the vibrations of nanoparticles in self-assembled Maxwell and hexagonal lattices at the nanometer resolution, measuring a series of otherwise inaccessible properties such as phonon spectra and nonlinear lattice deformation paths. These properties are experimentally modulated by ionic strength, captured by our discrete mechanical model considering the complexity of nanoscale interactions and thermal fluctuations. The experiment-theory integration bridges mechanical metamaterials and colloidal self-assembly, opening new opportunities to manufacture phononic devices with solution processibility, transformability, light weight, and emergent functions, at underexplored length, frequency, and energy scales.

Controllable Freezing Transparency for Water Ice on Scalable Graphene Films on Copper
Bernhard Fickl, Teresa M. Seifried, Erwin Rait, Jakob Genser, Thomas Wicht, Jani Kotakoski, G\"unther Rupprechter, Alois Lugstein, Dengsong Zhang, Christian Dipolt, Hinrich Grothe, Dominik Eder, Bernhard C. Bayer
arXiv:2403.15629v1 Announce Type: new Abstract: Control of water ice formation on surfaces is of key technological and economic importance, but the fundamental understanding of ice nucleation and growth mechanisms and the design of surfaces for controlling water freezing behaviour remain incomplete. Graphene is a two-dimensional (2D) material that has been extensively studied for its peculiar wetting properties with liquid water incl. a heavily debated wetting transparency. Furthermore, graphene is the parent structure of soot particles that are heavily implicated as nuclei in atmospheric ice formation and consequently graphene is often used as a model surface for computational ice nucleation studies. Despite this, to date experimental reports on ice formation on scalable graphene films remain missing. Towards filling this gap, we here report on the water freezing behaviour on scalably grown chemical vapour deposited (CVD) graphene films on application-relevant polycrystalline copper (Cu). We find that as-grown CVD graphene on Cu can be (as we term it) freezing transparent i.e. the graphene presence does not change the freezing temperature curves of liquid water to solid ice on Cu in our measurements. Such freezing transparency has to date not been considered. We also show that chemical functionalization of the graphene films can result in controllable changes to the freezing behaviour to lower/higher temperatures and that also the observed freezing transparency can be lifted via functionalization. Our work thereby introduces the concept of freezing transparency of graphene on a metal support and also introduces scalable CVD graphene/Cu as an ultimately thin platform towards control of ice nucleation behaviour on a technologically highly relevant metal.

An Anisotropic Constitutive Relationship by a Series of 8 Chain Models
Libin Yang, Teng Long, Lixiang Yang
arXiv:2403.15689v1 Announce Type: new Abstract: Hyperelastic models have been widely used to model polymers and soft tissues. However, most hyperelastic models are phenomenological material models. Based on statistical mechanics and molecular chain configuration, 8 chain model or Arruda-Boyce model is a physical model which can be used to understand how microstructures of chains affect macroscopic mechanical properties of polymers and soft tissues. Mechanical properties of many polymers and soft tissues are directional dependent. Polymer matrix can be reinforced by fibers. For soft tissues, ligaments and tendons will lead to anisotropic properties. Since matrix and reinforcements are composed of similar microstructural molecular chains, they can be modeled by using the same mathematical model. In this paper, a series of 8 chain models is used to understand composite properties. That is, an isotropic 8 chain model will be used to model matrix and anisotropic 8 chain models will be used to model fibers. Replacing I_1 in isotropic 8 chain model with I_4 in anisotropic 8 chain model is physically corresponding to changing representative 8 chain cubic cell to 8 chain slender cell. This treatment not only simplifies exist anisotropic mathematical structures but also keeps microscopic physics of 8 chain model unchanged.

Screened hydrogen model of excitons in semiconducting nanoribbons
Cesar E. P. Villegas, Alexandre R. Rocha
arXiv:2403.15793v1 Announce Type: new Abstract: The optical response of quasi-one-dimensional systems is often dominated by tightly bound excitons, that significantly influence their basic electronic properties. Despite their importance for device performance, accurately predicting their excitonic effects typically requires computationally demanding many-body approaches. Here, we present a simplified model to describe the static macroscopic dielectric function, which depends only on the width of the quasi-one-dimensional system and its polarizability per unit length. We show that at certain interaction distances, the screened Coulomb potential is greater than its bare counterpart, which results from the enhanced repulsive electron-electron interactions. As a test case, we study fourteen different nanoribbons, twelve of them armchair graphene nanoribbons of different families. Initially, we devised a simplified equation to estimate the exciton binding energy and extension that provides results comparable to those from the full Bethe-Salpeter equation, albeit for a specific nanoribbon family. Then, we used our proposed screening potential to solve the 1D Wannier-Mott equation, which turn out to be broad approach, that is able to predict binding energies that match quite well the ones obtained with the Bethe-Salpeter equation, irrespective of the nanoribbon family.

Combining genetic algorithm and compressed sensing for features and operators selection in symbolic regression
Aliaksei Mazheika, Sergey V. Levchenko, Luca M. Ghiringhelli
arXiv:2403.15816v1 Announce Type: new Abstract: Symbolic-inference methods have recently found a broad application in materials science. In particular, the Sure-Independence Screening and Sparsifying Operator (SISSO) performs symbolic regression and classification by adopting compressed sensing for the selection of an optimized subset of features and mathematical operators out of a given set of candidates. However, SISSO becomes computationally unpractical when the set of candidate features and operators exceeds the size of few tens. In the present work, we combine SISSO with a genetic algorithm (GA) for the global search of the optimal subset of features and operators. We demonstrate that GA-SISSO efficiently finds more accurate predictive models than the original SISSO, due to the possibility to access a larger input feature and operator space. GA-SISSO was applied for the search of the model for the prediction of carbon-dioxide adsorption energies on semiconductor oxides. The obtained with GA-SISSO model has much higher accuracy compared to models previously discussed in the literature (based solely on the O 2p-band center). The analysis of features importance shows that, besides the O 2p-band center, the contribution of the electrostatic potential above adsorption sites and the surface formation energies are also important.

The fractional quantum Hall nematics on the first Landau level in a tilted field
Dan Ye, Chen-Xin Jiang, Zi-Xiang Hu
arXiv:2403.15820v1 Announce Type: new Abstract: We investigated the behavior of fractional quantum Hall (FQH) states in a two-dimensional electron system with layer thickness and an in-plane magnetic field. Our comparisons across various filling factors within the first Landau level revealed a crucial observation. A slight in-plane magnetic field specifically enhances the nematic order of the $\nu = 7/3$ FQH state. For this particular filling, through calculating the energy gap, the Ising nematic order parameter, the pair-correlation function, and the static structure factor, we observed that as the in-plane magnetic field increases, the system first enters into an anisotropic FQH phase without closing the spectrum gap, then the FQH nematic (FQHN) phase after neutral gap closing. The system eventually enters a gapless one-dimensional charge density wave (CDW) phase for a large in-plane field. We thus provide a full phase diagram of the $\nu = 7/3$ state in a tilted magnetic field, demonstrating the existence of the FQHN, which aligns with recent resonant inelastic light scattering (RILS) experimental observations.

Ferromagnetic Ising model on the hierarchical pentagon lattice
Takumi Oshima, Tomotoshi Nishino
arXiv:2403.15829v1 Announce Type: new Abstract: Thermodynamic properties of the ferromagnetic Ising model on the hierarchical pentagon lattice is studied by means of the tensor network methods. The lattice consists of pentagons, where 3 or 4 of them meet at each vertex. Correlation functions on the surface of the system up to n = 10 layers are evaluated by means of the time evolving block decimation (TEBD) method, and the power low decay is observed in the high temperature region. The recursive structure of the lattice enables complemental numerical study for larger systems, by means of a variant of the corner transfer matrix renormalization group (CTMRG) method. Calculated spin expectation value shows that there is a mean-field type order-disorder transition at T1 = 1.58 on the surface of the system. On the other hand, the bulk part exhibits the transition at T2 = 2.269. Consistency of these calculated results is examined.

Engineering the electronic and magnetic properties of monolayer TiS$_2$ through systematic transition-metal doping
Sara Asadi Toularoud, Hanif Hadipour, Hamid Rahimpour Soleimani
arXiv:2403.15850v1 Announce Type: new Abstract: Layered materials that exhibit magnetic ordering in their pristine form are very rare. Several standard approaches, such as adsorption of atoms, introduction of point defects, and edge engineering, have been developed to induce magnetism in two-dimensional materials. In this way, we investigate the electronic and magnetic properties of monolayer TiS$_2$ doped with 3$d$ transition metals (TMs) atoms in both octahedral 1T and trigonal prismatic 1H structures using first-principles calculations. In its pristine form, TiS$_2$ is a non-magnetic semiconductor. The bands near the Fermi energy primarily exhibit $d$ orbital characters, and due to the presence of ideal octahedral and trigonal arrangements, they are well separated from other bands with $p$ character. Upon substituting 3$d$-TM atoms in both structures, a variety of electronic and magnetic phases emerge, including magnetic semiconductor, magnetic half-metal, non-magnetic metal, and magnetic metal. Chromium exhibits the largest magnetic moment in both the 1T and 1H structures. The 1T structure shows a slightly higher magnetic moment of 3.419 $\mu_B$ compared to the 1H structure 3.138 $\mu_B$, attributed to the distorted octahedral structure of the 1T structure. Unlike pristine TiS$_2$, the deficiency in saturation of neighboring S atoms in the presence of impurities leads to the proximity of energy levels of $d$ and $p$ states, resulting in unexpectedly sizable magnetic moments. Another interesting case is Cobalt, which leads to a magnetic moment of approximately 0.805 $\mu_B$ in the 1H structure, while the Co exhibits a non-magnetic state in the 1H structure. These materials demonstrate a high degree of tunability and can be optimized for various magnetic applications.

Observation of the dual quantum spin Hall insulator by density-tuned correlations in a van der Waals monolayer
Jian Tang, Thomas Siyuan Ding, Hongyu Chen, Anyuan Gao, Tiema Qian, Zumeng Huang, Zhe Sun, Xin Han, Alex Strasser, Jiangxu Li, Michael Geiwitz, Mohamed Shehabeldin, Vsevolod Belosevich, Zihan Wang, Yiping Wang, Kenji Watanabe, Takashi Taniguchi, David C. Bell, Ziqiang Wang, Liang Fu, Yang Zhang, Xiaofeng Qian, Kenneth S. Burch, Youguo Shi, Ni Ni, Guoqing Chang, Su-Yang Xu, Qiong Ma
arXiv:2403.15912v1 Announce Type: new Abstract: The convergence of topology and correlations represents a highly coveted realm in the pursuit of novel quantum states of matter. Introducing electron correlations to a quantum spin Hall (QSH) insulator can lead to the emergence of a fractional topological insulator and other exotic time-reversal-symmetric topological order, not possible in quantum Hall and Chern insulator systems. However, the QSH insulator with quantized edge conductance remains rare, let alone that with significant correlations. In this work, we report a novel dual QSH insulator within the intrinsic monolayer crystal of TaIrTe4, arising from the interplay of its single-particle topology and density-tuned electron correlations. At charge neutrality, monolayer TaIrTe4 demonstrates the QSH insulator that aligns with single-particle band structure calculations, manifesting enhanced nonlocal transport and quantized helical edge conductance. Interestingly, upon introducing electrons from charge neutrality, TaIrTe4 only shows metallic behavior in a small range of charge densities but quickly goes into a new insulating state, entirely unexpected based on TaIrTe4's single-particle band structure. This insulating state could arise from a strong electronic instability near the van Hove singularities (VHS), likely leading to a charge density wave (CDW). Remarkably, within this correlated insulating gap, we observe a resurgence of the QSH state, marked by the revival of nonlocal transport and quantized helical edge conduction. Our observation of helical edge conduction in a CDW gap could bridge spin physics and charge orders. The discovery of a dual QSH insulator introduces a new method for creating topological flat minibands via CDW superlattices, which offer a promising platform for exploring time-reversal-symmetric fractional phases and electromagnetism.

Generalized Kramers-Wanier Duality from Bilinear Phase Map
Han Yan, Linhao Li
arXiv:2403.16017v1 Announce Type: new Abstract: We present the Bilinear Phase Map (BPM), a concept that extends the Kramers-Wannier (KW) transformation to investigate unconventional gapped phases, their dualities, and phase transitions. Defined by a matrix of $\mathbb{Z}_2$ elements, the BPM not only encapsulates the essence of KW duality but also enables exploration of a broader spectrum of generalized quantum phases and dualities. By analyzing the BPM's linear algebraic properties, we elucidate the loss of unitarity in duality transformations and derive general non-invertible fusion rules. Applying this framework to (1+1)D systems yields the discovery of new dualities, shedding light on the interplay between various Symmetry Protected Topological (SPT) and Spontaneous Symmetry Breaking (SSB) phases. Additionally, we construct a duality web that interconnects these phases and their transitions, offering valuable insights into relations between different quantum phases.

Pressure-tuning topological phase transitions in Kagome superconductor CsTi$_3$Bi$_5$
Wenfeng Wu, Xiaocheng Bai, Xianlong Wang, Dayong Liu, Zhi Zeng, Liangjian Zou
arXiv:2403.16119v1 Announce Type: new Abstract: Recently, the Kagome metal CsTi$_3$Bi$_5$ has exhibited several novel quantum properties similar to CsV$_3$Sb$_5$, such as nontrivial topology, double-dome superconductivity, and flat band features. However, CsTi$_3$Bi$_5$ lacks the charge-density wave (CDW) present in CsV$_3$Sb$_5$, making the study of its emergence of double-dome superconductivity a focus of research. In this work, we have identified an order parameter, the three-band Z$_2$ topological index, that can describe the superconducting phase diagram of CsTi$_3$Bi$_5$ under pressure. Its evolution with pressure follows the expected behavior for superconductivity. Furthermore, the results of the Fermi surface under pressure reveal the potential presence of a Lifshitz transition in the vicinity of the vanishing point of the superconducting temperature change with pressure in CsTi$_3$Bi$_5$. These results indicate that the superconducting behavior of CsTi$_3$Bi$_5$ under pressure is caused by changes in the electronic structure leading to alterations in the topological properties, provide new insights and approaches for understanding the superconducting phenomenon in Kagome metals.

Ideal spin-polarized Weyl-half-semimetal with a single pair of Weyl points in half-Heusler compounds XCrTe (X=K, Rb)
Hongshuang Liu, Jin Cao, Zeying Zhang, Jiashuo Liang, Liying Wang, Shengyuan A. Yang
arXiv:2403.16195v1 Announce Type: new Abstract: Realizing ideal Weyl semimetal state with a single pair of Weyl points has been a long-sought goal in the field of topological semimetals. Here, we reveal such a state in the Cr-based half-Heusler compounds XCrTe (X=K, Rb). We show that these materials have a half metal ground state, with Fermi level crossing only one spin channel. Importantly, the Fermi surface is clean, consisting of the minimal number (i.e., a single pair) of spin-polarized Weyl points, so the state represents an ideal Weyl half semimetal. We show that the locations of the two Weyl points and the associated Chern vector can be flexibly tuned by rotating the magnetization vector. The minimal surface Fermi arc pattern and its contribution to anomalous Hall transport are discussed. Our finding offers an ideal material platform for exploring magnetic Weyl fermions, which will also facilitate the interplay between Weyl physics and spintronics.

Acceleration of Fe3+/Fe2+ cycle in garland-like MIL-101(Fe)/MoS2 nanosheets to promote peroxymonosulfate activation for sulfamethoxazole degradation
Ke Zhu, Wenlei Qin, Yaping Gan, Yizhe Huang, Zhiwei Jiang, Yuwen Chen, Xin Li, Kai Yan
arXiv:2403.16200v1 Announce Type: new Abstract: Iron-based molybdenum disulfide (Fe-MoS2) has emerged as a Fenton-like catalyst for the highly efficient degradation of antibiotics, but the structure-activity relationship remains elusive. Herein, garland-like MIL-101(Fe)/MoS2 nanosheets (MMS) with dual metal active sites (Fe and Mo) and rich sulfur vacancies were fabricated to directly activate peroxymonosulfate (PMS) for fast degradation of different organic pollutants (phenols, dyes and drugs), even in real water bodies. The MMS exhibited extremely fast catalytic rate constant of 0.289 min-1 in the degradation of sulfamethoxazole (SMX), which was about 36 and 29 times that of single MoS2 (0.008 min-1) and MIL-101(Fe) (0.01 min-1). Moreover, MMS with good stability and reusability could reach 92% degradation of SMX after 5 cycles. Quenching experiments and electron spin resonance (ESR) tests revealed that hydroxyl radicals (.OH) and singlet oxygen (1O2) were the dominant reactive oxygen species (ROS) for SMX degradation. The integration of experimental works, characterization techniques and density functional theory (DFT) calculations unraveled that the formation of sulfur vacancies in MMS catalyst could expose more Mo sites, improve the charge density and boost the electron transfer, which was conducive to accelerating the Fe3+/Fe2+ cycle for enhancing the activation of PMS. Finally, the C-N, N-O, S-N, C-O and C-S bonds of SMX were easily attacked by ROS to generate the nontoxic intermediates in the MMS/PMS/SMX system. This study offers a new approach to designing high-performance Fe-MoS2 catalysts for the removal of organic pollutants.

The nontrivial effects of annealing on superconducting properties of Nb single crystals
Amlan Datta, Kamal R. Joshi, Giulia Berti, Sunil Ghimire, Aidan Goerdt, Makariy A. Tanatar, Deborah L. Schlagel, Matthew F. Besser, Dapeng Jing, Matthew Kramer, Maria Iavarone, Ruslan Prozorov
arXiv:2403.16279v1 Announce Type: new Abstract: The effect of annealing on the superconducting properties of niobium single crystals cut from the same master boule was studied by local and global magnetic measurements, as well as scanning tunneling microscopy (STM). The formation of large hydride precipitates was observed in unannealed samples. The variation in structural and magnetic properties was studied after annealing under high vacuum at 800 C, 1400 C, and near the melting point of niobium (2477 C) for a few seconds. The initial samples had a high hydrogen content. Polarized optics and magneto-optical studies show that the formation of large niobium hydride precipitates is suppressed already by 800 C annealing. However, the overall superconducting properties in the annealed samples did not improve after annealing, and in fact, worsened. The superconducting transition temperature decreased, the upper critical field increased, and the pinning strength increased. Parallel studies were conducted using STM, where the sample was annealed initially at 400 C, measured, annealed again at 1700 C, and measured again. These studies revealed a ``dirty'' superconducting gap with a significant spatial variation of tunneling conductance after annealing at 400 C. The clean gap was recovered after annealing at 1700 C. It is likely that these results are due to oxygen redistribution near the surface, which is always covered by oxide layers in as-grown crystals. Overall, the results indicate that vacuum annealing at least up to 1400 C, while expected to remove a large amount of hydrogen, introduces additional nanosized defects, perhaps hydride precipitates, that act as efficient pair-breaking and pinning centers.

Evidence for a finite-momentum Cooper pair in tricolor $d$-wave superconducting superlattices
T. Asaba, M. Naritsuka, H. Asaeda, Y. Kosuge, S. Ikemori, S. Suetsugu, Y. Kasahara, Y. Kohsaka, T. Terashima, A. Daido, Y. Yanase, Y. Matsuda
arXiv:2403.16496v1 Announce Type: new Abstract: Fermionic superfluidity with a nontrivial Cooper-pairing, beyond the conventional Bardeen-Cooper-Schrieffer state, is a captivating field of study in quantum many-body systems. In particular, the search for superconducting states with finite-momentum pairs has long been a challenge, but establishing its existence has long suffered from the lack of an appropriate probe to reveal its momentum. Recently, it has been proposed that the nonreciprocal {\cred electron} transport is the most {\cred powerful} probe for the finite-momentum pairs, {\cred because it directly couples} to the supercurrents. Here we reveal such a pairing state by the non-reciprocal transport on tricolor superlattices with strong spin-orbit coupling combined with broken inversion-symmetry consisting of atomically thin $d$-wave superconductor CeCoIn$_5$. We find that while the second-harmonic resistance exhibits a distinct dip anomaly at the low-temperature ($T$)/high-magnetic field ($H$) corner in the $HT$-plane for ${\bm H}$ applied to the antinodal direction of the $d$-wave gap, such an anomaly is absent for ${\bm H}$ along the nodal direction. By meticulously isolating extrinsic effects due to vortex dynamics, we reveal the presence of a non-reciprocal response originating from intrinsic superconducting properties characterized by finite-momentum pairs. We attribute the high-field state to the helical superconducting state, wherein the phase of the order parameter is spontaneously spatially modulated.

Imaging quantum interference in a monolayer Kitaev quantum spin liquid candidate
Y. Kohsaka, S. Akutagawa, S. Omachi, Y. Iwamichi, T. Ono, I. Tanaka, S. Tateishi, H. Murayama, S. Suetsugu, K. Hashimoto, T. Shibauchi, M. O. Takahashi, M. G. Yamada, S. Nikolaev, T. Mizushima, S. Fujimoto, T. Terashima, T. Asaba, Y. Kasahara, Y. Matsuda
arXiv:2403.16553v1 Announce Type: new Abstract: Single atomic defects are prominent windows to look into host quantum states because collective responses from the host states emerge as localized states around the defects. Friedel oscillations and Kondo clouds in Fermi liquids are quintessential examples. However, the situation is quite different for quantum spin liquid (QSL), an exotic state of matter with fractionalized quasiparticles and topological order arising from a profound impact of quantum entanglement. Elucidating the underlying local electronic property has been challenging due to the charge neutrality of fractionalized quasiparticles and the insulating nature of QSLs. Here, using spectroscopic-imaging scanning tunneling microscopy, we report atomically resolved images of monolayer $\alpha$-RuCl$_3$, the most promising Kitaev QSL candidate, on metallic substrates. We find quantum interference in the insulator manifesting as incommensurate and decaying spatial oscillations of the local density of states around defects with a characteristic bias dependence. The oscillation differs from any known spatial structures in its nature and does not exist in other Mott insulators, implying it is an exotic oscillation involved with excitations unique to $\alpha$-RuCl$_3$. Numerical simulations can reproduce the observed oscillation by assuming that itinerant Majorana fermions of Kitaev QSL are scattered across the Majorana Fermi surface. The oscillation provides a new approach to exploring Kitaev QSLs through the local response against defects like Friedel oscillations in metals.

Intrinsic Dipole Hall effect in tMoTe$_2$ moir\'{e}: magnetoelectricity and contact-free signature of topological transitions
Feng-Ren Fan, Cong Xiao, Wang Yao
arXiv:2403.16586v1 Announce Type: new Abstract: We discover an intrinsic dipole Hall effect in a variety of magnetic insulating states at integer fillings of twisted MoTe$_2$ moir\'e superlattice, including topologically trivial and nontrivial ferro-, antiferro-, and ferri-magnetic configurations. The dipole Hall current, in linear response to in-plane electric field, generates an in-plane orbital magnetization $M_{\parallel}$ along the field, through which an AC field can drive magnetization oscillation up to THz range. Upon the continuous topological phase transitions from trivial to quantum anomalous Hall states in both ferromagnetic and antiferromagnetic configurations, the dipole Hall current and $M_{\parallel}$ have an abrupt sign change, enabling contact free detection of the transitions through the magnetic stray field. In configurations where the linear response is forbidden by symmetry, the dipole Hall current and $M_{\parallel}$ appear as a crossed nonlinear response to both in-plane and out-of-plane electric fields. These magnetoelectric phenomena showcase novel functionalities of insulators from the interplay between magnetism, topology and electrical polarization.

Universal properties of branched copolymers in dilute solutions
K. Haydukivska, V. Blavatska
arXiv:2403.16598v1 Announce Type: new Abstract: We analyze the universal conformational properties of complex copolymer macromolecules, based on two topologies: the rosette structure containing $f_c$ linear branches and $f_r$ closed loops grafted to the central core, and the symmetric pom-pom structure, consisting of a backbone linear chain terminated by two branching points with functionalities $f$. We assume that the constituent strands (branches) of these structures can be of two different chemical species $a$ and $b$. Depending on the solvent conditions, the inter- or intrachain interactions of some links may vanish, which corresponds to $\Theta$-state of the corresponding polymer species. Applying both the analytical approach within the frames of direct polymer renormalization and numerical simulations based on the lattice model of polymer, we evaluated the set of parameters characterizing the size properties of constituent parts of two complex topologies and estimated quantitatively the impact of interactions between constituent parts on these size characteristics.

Orientation-Driven Large Magnetic Hysteresis of Er(III) Cyclooctatetraenide-Based Single-Ion Magnets Adsorbed on Ag(100)
Vladyslav Romankov, Moritz Bernhardt, Martin Heinrich, Diana Vaclavkova, Katie Harriman, Ni\'eli Daff\'e, Bernard Delley, Maciej Damian Korzy\'nski, Matthias Muntwiler, Christophe Cop\'eret, Muralee Murugesu, Frithjof Nolting, Jan Dreiser
arXiv:2403.16629v1 Announce Type: new Abstract: The molecular self-assembly and the magnetic properties of two cyclooctatetraenide (COT) - based single-ion magnets (SIM) adsorbed on Ag(100) in the sub-monolayer range are reported. Our study combines scanning-tunneling microscopy, X-ray photoemission spectroscopy and polarized X-ray absorption spectroscopy to show that Cp*ErCOT (Cp* = 1,2,3,4,5-pentamethylcyclopentadienide anion) SIMs self-assemble as alternating compact parallel rows including standing-up and lying-down conformations, following the main crystallographic directions of the substrate. Conversely, K[Er(COT)$_2$], obtained from subliming the [K(18-c-6)][Er(COT)$_2$]$\cdot$ 2THF salt, forms uniaxially ordered domains with the (COT)$^{2-}$ rings perpendicular to the substrate plane. The polarization-dependent X-ray absorption spectra reproduced by the multiX simulations suggest that the strong in-plane magnetic anisotropy of K[Er(COT)$_2$]/Ag(100) and the weak out-of-plane anisotropy of Cp*ErCOT/Ag(100) can be attributed to the strikingly different surface ordering of these two complexes. Compared to the bulk phase, surface-supported K[Er(COT)$_2$] exhibits a similarly large hysteresis opening, while the Cp*ErCOT shows a rather small opening. This result reveals that despite structural similarities, the two organometallic SMMs have strongly different magnetic properties when adsorbed on the metal substrate, attributed to the different orientations and the resulting interactions of the ligand rings with the surface.

Phase separation dynamics in a symmetric binary mixture of ultrasoft particles
Tanmay Biswas, Gerhard Kahl, Gaurav P. Shrivastav
arXiv:2403.16663v1 Announce Type: new Abstract: Phase separation plays an role in determining the self-assembly of biological and soft-matter systems. In biological systems, liquid-liquid phase separation inside a cell leads to the formation of various macromolecular aggregates. The interaction among these aggregates is soft, i.e., these can significantly overlap at a small energy cost. From the computer simulation point of view, these complex macromolecular aggregates are generally modeled by the so-called soft particles. The effective interaction between two particles is defined via the generalized exponential potential (GEM-n) with n = 4. Here, using molecular dynamics simulations, we study the phase separation dynamics of a size-symmetric binary mixture of ultrasoft particles. We find that when the mixture is quenched to a lower temperature below the critical temperature, the two components spontaneously start to separate. Domains of the two components form, and the equal-time order parameter reveals that the domains grow in a power-law manner with exponent 1/3, which is consistent with the Lifshitz-Slyozov law for conserved systems. Further, the static structure factor shows a power-law decay with exponent 4 consistent with the Porod law.

Giant tunability of magnetoelasticity in Fe$_4$N system: Platform for unveiling correlation between magnetostriction and magnetic damping
Keita Ito, Ivan Kurniawan, Yusuke Shimada, Yoshio Miura, Yasushi Endo, Takeshi Seki
arXiv:2403.16679v1 Announce Type: new Abstract: Flexible spintronics has opened new avenue to promising devices and applications in the field of wearable electronics. Particularly, miniaturized strain sensors exploiting the spintronic function have attracted considerable attention, in which the magnetoelasticity linking magnetism and lattice distortion is a vital property for high-sensitive detection of strain. This paper reports the demonstration that the magnetoelastic properties of Fe$_4$N can be significantly varied by partially replacing Fe with Co or Mn. The high quality Fe$_4$N film exhibits large negative magnetostriction along the [100] direction ($\lambda_{100}$) of -121 ppm while Fe$_{3.2}$Co$_{0.8}$N shows $\lambda_{100}$ of +46 ppm. This wide-range tunability of $\lambda_{100}$ from -121 to +46 across 0 allows us to thoroughly examine the correlation between the magnetoelasticity and other magnetic properties. The strong correlation between $\lambda_{100}$ and magnetic damping ($\alpha$) is found. The enhanced extrinsic term of $\alpha$ is attributable to the large two magnon scattering coming from the large magnetostriction. In addition, the density of states at the Fermi level plays a primal role to determine both $\lambda_{100}$ and the intrinsic term of $\alpha$. Thanks to the giant tunability and the bipolarity of magnetoelasticity, magnetic nitrides are candidate materials for high-sensitive spintronic strain sensors.

Layer Control of Magneto-Optical Effects and Their Quantization in Spin-Valley Splitting Antiferromagnets
Jiaqi Feng, Xiaodong Zhou, Meiling Xu, Jingming Shi, Yinwei Li
arXiv:2403.16701v1 Announce Type: new Abstract: Magneto-optical effects (MOE), interfacing the fundamental interplay between magnetism and light, have served as a powerful probe for magnetic order, band topology, and valley index. Here, based on multiferroic and topological bilayer antiferromagnets (AFMs), we propose a layer control of MOE (L-MOE), which is created and annihilated by layer-stacking or an electric field effect. The key character of L-MOE is the sign-reversible response controlled by ferroelectric polarization, the Neel vector, or the electric field direction. Moreover, the sign-reversible L-MOE can be quantized in topologically insulating AFMs. We reveal that the switchable L-MOE originates from the combined contributions of spin-conserving and spin-flip interband transitions in spin-valley splitting AFMs, a phenomenon not observed in conventional AFMs. Our findings bridge the ancient MOE to the emergent realms of layertronics, valleytronics, and multiferroics and may hold immense potential in these fields.

Phase Transformation in Lithium Niobate-Lithium Tantalate Solid Solutions (LiNb$_{1-x}$Ta$_x$O$_3$)
Fatima El Azzouzi, Detlef Klimm, Alexander Kapp, Leonard M. Verhoff, Nils A. Sch\"afer, Steffen Ganschow, Klaus-Dieter Becker, Simone Sanna, Holger Fritze
arXiv:2403.16717v1 Announce Type: new Abstract: The investigation of the structural phase transition in the vicinity of the Curie temperature $T_c$ of LiNb$_{1-x}$Ta$_x$O$_3$ crystals is motivated by the expected combination of advantageous high-temperature properties of LiNbO$_3$ and LiTaO$_3$, including high piezoelectric modules and remarkable high-temperature stability, respectively. $T_c$ marks the ultimate limit for exploiting the piezoelectric properties, however transition related structural modifications might impact this and other properties even below $T_c$. Remarkably, the phase transition from the ferroelectric to the paraelectric phase, whose temperature strongly depends on the composition $x$, shows a significant drop in the activation energy of the electrical conductivity. The magnitude, temperature dependence and underlying mechanisms of this drop are discussed from a microscopic perspective. Molecular dynamics calculations in the framework of the density functional theory show that substantial displacements of the cations occur below $T_c$ for both the end compounds LiNbO$_3$ and LiTaO$_3$, and might thus affect the electrical conductivity. Above $T_c$, the migration of lithium ions is presumably facilitated by a shortened diffusion path for the most favorable jump of the lithium ions. Electronic contributions to the conductivity, which become important above 900 K, are explained within the polaronic picture by the formation and migration of free small polarons.

Skyrmionic device for three dimensional magnetic field sensing enabled by spin-orbit torques
Sabri Koraltan, Rahul Gupta, Reshma Peremadathil Pradeep, Fabian Kammerbauer, Iryna Kononenko, Klemens Pr\"ugl, Michael Kirsch, Bernd Aichner, Santiago Helbig, Florian Bruckner, Claas Abert, Andrada Oana Mandru, Armin Satz, Gerhard Jakob, Hans Josef Hug, Mathias Kl\"aui, Dieter Suess
arXiv:2403.16725v1 Announce Type: new Abstract: Magnetic skyrmions are topologically protected local magnetic solitons that are promising for storage, logic or general computing applications. In this work, we demonstrate that we can use a skyrmion device based on [W/CoFeB/MgO] 1 0 multilayers for three-dimensional magnetic field sensing enabled by spin-orbit torques (SOT). We stabilize isolated chiral skyrmions and stripe domains in the multilayers, as shown by magnetic force microscopy images and micromagnetic simulations. We perform magnetic transport measurements to show that we can sense both in-plane and out-of-plane magnetic fields by means of a differential measurement scheme in which the symmetry of the SOT leads to cancelation of the DC offset. With the magnetic parameters obtained by vibrating sample magnetometry and ferromagnetic resonance measurements, we perform finite-temperature micromagnetic simulations, where we investigate the fundamental origin of the sensing signal. We identify the topological transformation between skyrmions, stripes and type-II bubbles that leads to a change in the resistance that is read-out by the anomalous Hall effect. Our study presents a novel application for skyrmions, where a differential measurement sensing concept is applied to quantify external magnetic fields paving the way towards more energy efficient applications in skyrmionics based spintronics.

Chemical homogenization for non-mixing reactive interfaces in porous media
Winston Lindqwister, Manolis Veveakis, Martin Lesueur
arXiv:2403.16770v1 Announce Type: new Abstract: Porous media, while ubiquitous across many engineering disciplines, is inherently difficult to characterize due to their innate stochasticity and heterogeneity. The key for predicting porous material behavior comes down to the structuring of its microstructure, where the linkages of microstructural properties to mesoscale effects remain as one of the key questions in unlocking understanding of this class of materials. One proposed method of linking scales comes down to using Minkowski functionals -- geometric morphometers that describe the spatial and topological features of a convex space -- to draw connections from microstructural form to mesoscale features. In this work, chemical equilibrium and kinetics on a microstructure surface were explored, with Minkowski functionals used as the basis for relating microstructural geometry to chemical performance. Using surface CRNs to model chemical behavior -- a novel asynchronous cellular automaton -- linkages were found between the Minkowski functionals and equilibrium equilibrium constant, as well as properties related to the dynamics of the system's reaction quotient.

Embedded skyrmion bags in thin films of chiral magnets
Luyan Yang, Andrii S. Savchenko, Fengshan Zheng, Nikolai S. Kiselev, Filipp N. Rybakov, Xiaodong Han, Stefan Bl\"ugel, Rafal E. Dunin-Borkowski
arXiv:2403.16931v1 Announce Type: new Abstract: Magnetic skyrmions are topologically nontrivial spin configurations that possess particle-like properties. Earlier research was mainly focused on a specific type of skyrmion with topological charge Q = -1. However, theoretical analyses of two-dimensional chiral magnets have predicted the existence of skyrmion bags -- solitons with arbitrary positive or negative topological charge. Although such spin textures are metastable states, recent experimental observations have confirmed the stability of isolated skyrmion bags in a limited range of applied magnetic fields. Here, by utilizing Lorentz transmission electron microscopy, we show the extraordinary stability of skyrmion bags in thin plates of B20-type FeGe. In particular, we show that skyrmion bags embedded within a skyrmion lattice remain stable even in zero or inverted external magnetic fields. A robust protocol for nucleating such embedded skyrmion bags is provided. Our results agree perfectly with micromagnetic simulations and establish thin plates of cubic chiral magnets as a powerful platform for exploring a broad spectrum of topological magnetic solitons.

Signatures of canted antiferromagnetism in infinite-layer nickelates studied by x-ray magnetic dichroism
G. Krieger, H. Sahib, F. Rosa, M. Rath, Y. Chen, A. Raji, P. V. B. Pinho, C. Lefevre, G. Ghiringhelli, A. Gloter, N. Viart, M. Salluzzo, D. Preziosi
arXiv:2403.16969v1 Announce Type: new Abstract: We report an experimental study of the magnetic properties of infinite-layer Nd1-xSrxNiO2 thin films by x-ray magnetic circular dichroism (XMCD) at Ni L3,2 and Nd M5,4 edges. We show that at low temperatures the out-of-plane component of the Ni1+ spin-moment is characterized by a rapid increase for magnetic fields below 1T , followed by a slower linear increase reaching a spin-moment value of 0.25uB/Ni at 9T in the case of superconducting Nd0.8Sr0.2NiO2. On the other hand, the Nd M5,4 XMCD shows a clear paramagnetic behaviour, which make both Ni- and Nd-spin-sublattices fully uncorrelated.The magnetic field and temperature dependencies of the Ni L3,2 XMCD data can be explained by assuming an out-of-plane canting of the strongly in-plane anti-ferromagnetic ordered Ni1+ spins. A symmetry lowering of the NiO2 planes observed via four-dimensional scanning transmission electron microscopy, triggering a DMI, can be responsible of the proposed Ni1+ spin-canting at zero-field. The resulting out-of-plane weak-ferromagnetic coupling under magnetic field explains the relatively large spin-moment and its magnetic field and temperature dependence.

Locally Purified Density Operators for Symmetry-Protected Topological Phases in Mixed States
Yuchen Guo, Jian-Hao Zhang, Shuo Yang, Zhen Bi
arXiv:2403.16978v1 Announce Type: new Abstract: We propose a tensor network approach known as the locally purified density operator (LPDO) to investigate the classification and characterization of symmetry-protected topological (SPT) phases in open quantum systems. We extend the concept of injectivity, originally associated with matrix product states and projected entangled pair states, to LPDOs in $(1+1)D$ and $(2+1)D$ systems, unveiling two distinct types of injectivity conditions inherent in short-range entangled density matrices. Within the LPDO framework, we outline a classification scheme for decohered average symmetry-protected topological (ASPT) phases, consistent with earlier results obtained through spectrum sequence techniques. We illustrate our framework with examples of ASPTs protected by fermion parity symmetry in both $(1+1)D$ and $(2+1)D$ systems. In addition, we discuss the classification of ASPT phases for a general group extension. We demonstrate examples of explicit construction of fixed-point LPDOs for ASPT phases including intrinsic ASPTs in $(1+1)D$ systems.

Geometeric Thermodynamics of Collapse of Gels
Asif Raza, Sanhita Das, Debasish Roy
arXiv:2403.16991v1 Announce Type: new Abstract: Stimulus-induced volumetric phase transition in gels may be potentially exploited for various bio-engineering and mechanical engineering applications. Since the discovery of the phenomenon in the 1970s, extensive experimental research has helped in understanding the phase transition and related critical phenomena. Yet, little insight is available on the evolving microstructure. In this article, we aim at unravelling certain geometric aspects of the micromechanics underlying discontinuous phase transition in polyacrylamide gels. Towards this, we use geometric thermodynamics and a Landau-Ginzburg type free energy functional involving a squared gradient, in conjunction with Flory-Huggins theory. We specifically exploit Ruppeiner's approach of Riemannian geometry-enriched thermodynamic fluctuation theory that has been previously employed to investigate phase transitions in van der Waals fluids and black holes. The framework equips us with a scalar curvature that relates to the microstructural interactions of a gel during phase transition and at critical points. This curvature also provides an insight into the universality class of phase transition and the nature of polymer-polymer interactions.

Multiple Chern bands in twisted MoTe$_2$ and possible non-Abelian states
Cheng Xu, Ning Mao, Tiansheng Zeng, Yang Zhang
arXiv:2403.17003v1 Announce Type: new Abstract: We investigate the moir\'e band structures and possible even denominator fractional quantum Hall state in small angle twisted bilayer MoTe$_2$, using combined large-scale local basis density functional theory calculation and continuum model exact diagonalization. Via large-scale first principles calculations at $\theta=1.89^{\circ}$, we find a sequence of $C=1$ moir\'e Chern bands, in analogy to Landau levels. Constructing the continuum model with multiple Chern bands and uniform Berry curvature in the second moir\'e band, we undertake band-projected exact diagonalization using unscreened Coulomb repulsion to pinpoint possible $\nu=-3/2$ non-Abelian states across a wide range of twist angles below $\theta=2.5^{\circ}$.

Multipartite entanglement distribution in a topological photonic network
Juan Zurita, Andr\'es Agust\'i Casado, Charles E. Creffield, Gloria Platero
arXiv:2403.15584v1 Announce Type: cross Abstract: In the ongoing effort towards a scalable quantum computer, multiple technologies have been proposed. Some of them exploit topological materials to process quantum information. In this work, we propose a lattice of photonic cavities with alternating hoppings to create a modified multidomain SSH chain, that is, a sequence of topological insulators made from chains of dimers. A qubit is then coupled to each boundary. We show this system is well suited for quantum information processing because topological transfer of photons through this one-dimensional lattice can entangle any set of qubits on demand, providing a scalable quantum platform. We verify this claim evaluating entanglement measures and witnesses proving that bipartite and multipartite entanglement is produced, even in the presence of some disorder.

Axion-like Interactions and CFT in Topological Matter, Anomaly Sum Rules and the Faraday Effect
Claudio Corian\`o, Mario Cret\`i, Stefano Lionetti, Dario Melle, Riccardo Tommasi
arXiv:2403.15641v1 Announce Type: cross Abstract: We discuss fundamental aspects of chiral anomaly-driven interactions in conformal field theory (CFT) in four spacetime dimensions. They find application in very general contexts, from early universe plasma to topological condensed matter. We outline the key shared characteristics of these interactions, specifically addressing the case of chiral anomalies, both for vector currents and gravitons. In the case of topological materials, the gravitational chiral anomaly is generated by thermal gradients via the (Tolman-Ehrenfest) Luttinger relation. In the CFT framework, a nonlocal effective action, derived through perturbation theory, indicates that the interaction is mediated by an excitation in the form of an anomaly pole, which appears in the conformal limit of the vertex. To illustrate this, we demonstrate how conformal Ward identities (CWIs) in momentum space allow us to reconstruct the entire chiral anomaly interaction in its longitudinal and transverse sectors just by inclusion of a pole in the longitudinal sector. Both sectors are coupled in amplitudes with an intermediate chiral fermion or a bilinear Chern-Simons current with intermediate photons. In the presence of fermion mass corrections, the pole transforms into a cut, but the absorption amplitude in the axial-vector channel satisfies mass-independent sum rules related to the anomaly in any chiral interaction. The detection of an axion-like/quasiparticle in these materials may rely on a combined investigation of these sum rules, along with the measurement of the angle of rotation of the plane of polarization of incident light when subjected to a chiral perturbation. This phenomenon serves as an analogue of a similar one in ordinary axion physics, in the presence of an axion-like condensate, that we rederive using axion electrodynamics.

Efficient semiclassical approximation for bound states in graphene in magnetic field with a small trigonal warping correction
Vladislav Rykhlov
arXiv:2403.15748v1 Announce Type: cross Abstract: This paper is devoted to the construction of efficient (simple to implement) explicit semiclassical asymptotic eigenfunctions of the Dirac operator for high-energy bound states in graphene in magnetic field. When considering excited states in graphene, a distortion called trigonal warping begins to play an~important role, see [7], [12]. We are dealing with a~trigonal warping correction, considering it to be small. While the standard semiclassical methods allow one to solve the eigenequations for operators if and only if quantization conditions are met, we, based on article [1], develop approaches that can be used in case these conditions are violated. The complete symbol turns out to be only close to integrable, which brings its own difficulties. The present paper relies heavily on the results from [3].

Shaping a Surface Microdroplet by Marangoni Forces along a Moving Contact Line of Four Immiscible Phases
Haichang Yang, Binglin Zeng, Qiuyun Lu, Yaowen Xing, Xiahui Gui, Yijun Cao, Ben Bin Xu, Xuehua Zhang
arXiv:2403.16019v1 Announce Type: cross Abstract: The ability to transfer microdroplets between fluid phases offers numerous advantages in various fields, enabling better control, manipulation, and utilization of small volumes of fluids in pharmaceutical formulations, microfluidics, and lab-on-a-chip devices, single-cell analysis or droplet-based techniques for nanomaterial synthesis. This study focuses on the stability and morphology of a sessile oil microdroplet at the four-phase contact line of solid-water-oil-air during the droplet transfer from underwater to air. We observed a distinct transition in microdroplet dynamics, characterized by a shift from a scenario dominated by Marangoni forces to one dominated by capillary forces. In the regime dominated by Marangoni forces, the oil microdroplets spread in response to the contact between the water-air interface and the water-oil interface and the emergence of an oil concentration gradient along the water-air interface. The spreading distance along the four-phase contact line follows a power law relationship of $t^{3/4}$, reflecting the balance between Marangoni forces and viscous forces. On the other hand, in the capillarity-dominated regime, the oil microdroplets remain stable at the contact line and after being transferred into the air. We identify the crossover between these two regimes in the parameter space defined by three factors: the approaching velocity of the solid-water-air contact line ($v_{cl}$), the radius of the oil microdroplet ($r_o$), and the radius of the water drop ($r_w$). Furthermore, we demonstrate how to use the four-phase contact line for shaping oil microdroplets using a full liquid process by the contact line lithography. The findings in this study may be also applied to materials synthesis where nanoparticles, microspheres, or nanocapsules are produced by microdroplet-based techniques.

Aggregate Frequency Width, Nuclear Hyperfine Coupling and Jahn-Teller Effect of $Cu^{2+}$ Impurity Ion ESR in $SrLaAlO_4$ Dielectric Resonator at $20$ Millikelvin
M. A. Hosain, J. -M. Le Floch, J. Krupka, M. E. Tobar
arXiv:2403.16315v1 Announce Type: cross Abstract: The impurity paramagnetic ion, $Cu^{2+}$ substitutes $Al$ in the $SrLaAlO_4$ single crystal lattice, this results in a $CuO_6$ elongated octahedron, the resulting measured g-factors shows four-fold axes variation condition. The aggregate frequency width of the electron spin resonance with the required minimum level of impurity concentration has been evaluated in single crystal $SrLaAlO_4$ at $20$ millikelvin. Measured parallel hyperfine constants, $A_{\scriptscriptstyle\parallel Cu}$, were determined to be $-155.7\times10^{-4}~cm^{-1},~ -163.0\times10^{-4}~cm^{-1},~ -178.3\times10^{-4}~cm^{-1} $ and$~-211.1\times10^{-4}~cm^{-1}$ at $9.072~GHz~(WGH_{4,1,1})$ for the nuclear magnetic quantum number $M_I=+\frac{3}{2},+\frac{1}{2},-\frac{1}{2}$,~and$-\frac{3}{2}$ respectively. The anisotropy of the hyperfine structure reveals a characteristics of static Jahn-Teller effect. The second-order-anisotropy-term, $\sim (\frac{spin-orbit~coupling}{10D_q})^2$, is significant and can not be disregarded, with the local strain dominating over the observed Zeeman-anisotropy-energy difference. The Bohr electron magneton, $\beta=9.23\times 10^{-24} JT^{-1}$, (within $-0.43\%$ so-called experimental error) has been found using the measured spin-Hamiltonian parameters. Measured nuclear dipolar hyperfine structure parameter $P_{\scriptscriptstyle\parallel}=12.3\times10^{-4}~cm^{-1}$ shows that the mean inverse third power of the electron distance from the nucleus is $\langle r^{-3}_q\rangle\simeq 5.23$ a.u. for $Cu^{2+}$ ion in the substituted $Al^{3+}$ ion site assuming nuclear electric quadruple moment $Q=-0.211$ barn.

Topological iron silicide with H* intermediate modulated surface for efficient electrocatalytic hydrogenation of nitrobenzene in neutral medium
Yuchen Wang, Yaoyu Liu, Zhiyue Zhao, Zhikeng Zheng, Alina M. Balu, Rafael Luque, Kai Yan
arXiv:2403.16455v1 Announce Type: cross Abstract: Electrocatalytic hydrogenation of nitrobenzene (Ph-NO2) reaction (EHNR) has been considered as a potential alternative to the traditional thermocatalytic process in the production of high-value aniline (Ph-NH2). However, due to the absence of robust catalyst and low surface H* coverage, the EHNR faces the challenges of undesired performance and indetermined mechanism. Herein, we construct a type of noble-metal free topological FeSi (M-FeSi) materials through a solvent-free microwave strategy for efficient EHNR in neutral medium. Impressively, benefiting from abundant active H* intermediates on the surface of M-FeSi catalyst, the topological M-FeSi catalyst exhibits 99.7% conversion of Ph-NO2 and 93.8% yield of Ph-NH2 after 200 C in neutral medium, which are superior to previous candidates and FeSi catalyst synthesized via the traditional arc-melting method under same conditions. Besides, theoretical calculations validate that high surface H* coverage over M-FeSi catalyst is conducive to switching the rate-determining step from Ph-NO2* Ph-NO* to Ph-NO* Ph-NHOH*, and thus decreasing the total energy barrier of electrocatalytic Ph-NH2 production.

Green fabrication of nickel-iron layered double hydroxides nanosheets efficient for the enhanced capacitive performance
Yuchen Wang, Zuo Chen, Man Zhang, Yaoyu Liu, Huixia Luo, Kai Yan
arXiv:2403.16487v1 Announce Type: cross Abstract: Rational synthesis of robust layered double hydroxides (LDHs) nanosheets for high-energy supercapacitors is full of challenges. Herein, we reported an ultrasonication-assisted strategy to eco-friendly fabricate NiFe-LDHs nanosheets for the enhanced capacitive behavior. The experimental results combined with different advanced characterization tools document that the utilization of ultrasonication has a profound effect on the morphology and thickness of the as-obtained NiFe-LDHs, alternatively affecting the capacitive behavior. It shows that NiFe-LDHs nanosheets prepared with 2-h ultrasonic treatments display the exceptional capacitive performance because of the synergetic effect of ultrathin thickness, large specific surface area, and high mesoporous volume. The maximum specific capacitance of Ni3Fe1-LDHs nanosheets with the thickness of 7.39 nm and the specific surface area of 77.16 m2 g-1 reached 1923 F g-1, which is competitive with most previously reported values. In addition, the maximum specific energy of the assembled NiFe-LDHs//AC asymmetric supercapacitor achieved 49.13 Wh kg-1 at 400 W kg-1. This work provides a green technology to fabricate LDHs nanosheets, and offers deep insights for understanding the relationship between the morphology/structure and capacitive behavior of LDHs nanosheets, which is helpful for achieving high-performance LDHs-based electrode materials.

In situ growth of hydrophilic nickel-cobalt layered double hydroxides nanosheets on biomass waste-derived porous carbon for high-performance hybrid supercapacitors
Yuchen Wang, Yaoyu Liu, Zuo Chen, Man Zhang, Biying Liu, Zhenhao Xu, Kai Yan
arXiv:2403.16506v1 Announce Type: cross Abstract: Rational design and cost-effective fabrication of layered double hydroxides (LDHs) nanosheets with extraordinary electrochemical performance is a key challenge for hybrid supercapacitors (HSCs). Herein, we report a facile in situ growth methodology to eco-friendly synthesize hydrophilic NiCo-LDHs nanosheets on biomass waste-derived porous carbon (BC) for robust high-performance HSC cathode. The in situ growth process under ultrasonication realizes the rational arrangement of NiCo-LDHs nanosheets on the surface of BC, which effectively increases the specific surface area, promotes the electronic conductivity and enhances the wettability of NiCo-LDHs nanosheets without affecting their thickness values. With the beneficial effects of ultrathin thickness of LDHs nanosheets (6.20 nm), large specific surface area (2324.1 m2 g-1), low charge transfer resistance (1.65 ohm), and high wettability with electrolyte (34-35 degree), the obtained Ni2Co1-LDHs/BC50 electrode possesses an ultra-high specific capacitance of 2390 F g-1 (956 C g-1) at 1 A g-1, which is superior to most reported values. Furthermore, an assembled Ni2Co1-LDHs/BC50//YP-80F HSC delivers a maximum specific energy of 52.47 Wh kg-1 at 375 W kg-1, and maintains a high capacitance retention of 75.9% even after 4000 cycles. This work provides a facile approach to fabricate LDHs nanosheets based cathode materials for high-performance HSCs.

Gas-phase condensation of carbonated silicate grains
Ga\"el Rouill\'e (Friedrich-Schiller-Universit\"at Jena, Max Planck Institute for Astronomy), Johannes Schmitt (Friedrich-Schiller-Universit\"at Jena, Max Planck Institute for Astronomy), Cornelia J\"ager (Friedrich-Schiller-Universit\"at Jena, Max Planck Institute for Astronomy), Thomas Henning (Max Planck Institute for Astronomy)
arXiv:2403.16925v1 Announce Type: cross Abstract: Reports on the detection of carbonates in planetary nebulae (PNe) and protostars suggested the existence of a mechanism that produce these compounds in stellar winds and outflows. A consecutive laboratory study reported a possible mechanism by observing the non-thermodynamic equilibrium (TE), gas-phase condensation of amorphous silicate grains with amorphous calcium carbonate inclusions. It concluded that water vapor was necessary to the formation of the carbonates. We present a laboratory study with pulsed laser ablation of an MgSi target in O$_2$ and CO$_2$ gases and report, in the absence of water vapor, the non-TE, gas-phase condensation of amorphous carbonated magnesium silicate dust. It consists of amorphous silicate grains with formula MgSiO$_3$ that comprise carbonate groups homogeneously dispersed in their structure. The infrared spectra of the grains show the characteristic bands of amorphous silicates and two bands at $\sim$6.3 and $\sim$7.0 $\mu$m that we assign to the carbonate groups. The silicate bands are not significantly affected at an estimated Si:C ratio of 9:1 to 9:2. Such grains could form in winds and outflows of evolved stars and PNe if C atoms are present during silicate condensation. Additionally, we find that Lyman-$\alpha$ radiation dissociates the carbonate groups at the surface of the carbonated silicate grains and we estimate the corresponding photodissociation cross section of (0.04 $\pm$ 0.02) $\times$ 10$^{-16}$ cm$^2$. Therefore, photodissociation would limit the formation of carbonate groups on grains in winds and outflows of stars emitting VUV photons and the carbonates observed in protostars have not formed by gas-phase condensation.

Entanglement-enabled symmetry-breaking orders
Cheng-Ju Lin, Liujun Zou
arXiv:2207.08828v2 Announce Type: replace Abstract: A spontaneous symmetry-breaking order is conventionally described by a tensor-product wave-function of some few-body clusters. We discuss a type of symmetry-breaking orders, dubbed entanglement-enabled symmetry-breaking orders, which cannot be realized by any tensor-product state. Given a symmetry breaking pattern, we propose a criterion to diagnose if the symmetry-breaking order is entanglement-enabled, by examining the compatibility between the symmetries and the tensor-product description. For concreteness, we present an infinite family of exactly solvable gapped models on one-dimensional lattices with nearest-neighbor interactions, whose ground states exhibit entanglement-enabled symmetry-breaking orders from a discrete symmetry breaking. In addition, these ground states have gapless edge modes protected by the unbroken symmetries. We also propose a construction to realize entanglement-enabled symmetry-breaking orders with spontaneously broken continuous symmetries. Under the unbroken symmetries, some of our examples can be viewed as symmetry-protected topological states that are beyond the conventional classifications.

Fermionic Isometric Tensor Network States in Two Dimensions
Zhehao Dai, Yantao Wu, Taige Wang, Michael P. Zaletel
arXiv:2211.00043v3 Announce Type: replace Abstract: We generalize isometric tensor network states to fermionic systems, paving the way for efficient adaptations of 1D tensor network algorithms to 2D fermionic systems. As the first application of this formalism, we developed and benchmarked a time-evolution block-decimation (TEBD) algorithm for real-time and imaginary-time evolution. The imaginary-time evolution produces ground-state energies for gapped systems, systems with a Dirac point, and systems with gapless edge modes to good accuracy. The real-time TEBD captures the scattering of two fermions and the chiral edge dynamics on the boundary of a Chern insulator.

$1/\varphi$ Spectrum of the Stress Dynamics with the Bak-Tang-Wiesenfeld Sandpile
Alexander Shapoval, Mikhail Shnirman
arXiv:2212.14726v3 Announce Type: replace Abstract: With the original Bak-Tang-Wisenefeld (BTW) sandpile we uncover the $1/\varphi$ noise in the mechanism maintaining self-organized criticality (SOC) - the question raised together with the concept of SOC. We posit that the dynamics of stress in the BTW sandpile follows quasi-cycles of graduate stress accumulation that end up with an abrupt stress-release and the drop of the system to subcritical state. In thermodynamic limit, the intra-cycle dynamics exhibits the $1/\varphi$ spectrum that extends infinitely and corresponds to the stress-release within the critical state.

Electrons trapped in graphene magnetic quantum dots with mass term
Mohammed El Azar, Ahmed Bouhlal, Ahmed Jellal
arXiv:2301.11211v2 Announce Type: replace Abstract: Owing to the Klein tunneling phenomenon, the permanent confinement or localization of electrons within a graphene quantum dot is unattainable. Nonetheless, a constant magnetic field can transiently ensnare an electron within the quantum dot, giving rise to what are known as quasi-bound states characterized by finite lifetimes. To prolong the retention of electrons within the quantum dot, we introduce a mass term into the Hamiltonian, thereby inducing an energy gap. We resolve the Dirac equation to ascertain the eigenspinors, and by ensuring their continuity at the boundaries, we investigate the scattering behavior. Our findings indicate that the presence of an energy gap can extend the lifetimes of these quasi-bound states within the quantum dot. In particular, we demonstrate that even in the absence of a magnetic field, the scattering efficiency attains significant levels when the energy gap gets closed to the incident energy of an electron traversing the quantum dot. It is found that an augmentation in the electron density within the quantum dot results in an enhancement of the electron-trapping time.

Magnetic field effect on tunneling through triple barrier in AB bilayer graphene
Mouhamadou Hassane Saley, Ahmed Jellal
arXiv:2301.12479v2 Announce Type: replace Abstract: We investigate electron tunneling in AB bilayer graphene through a triple electrostatic barrier of heights $U_i (i=2,3,4)$ subjected to a perpendicular magnetic field. By way of the transfer matrix method and using the continuity conditions at the different interfaces, the transmission probability is determined. Additional resonances appear for two-band tunneling at normal incidence, and their number is proportional to the value of $U_4$ in the case of $U_2U_4$, anti-Klein tunneling increases with $U_2$. The transmission probability exhibits an interesting oscillatory behavior when $U_3>U_2=U_4$ and $U_3 U_2=U_4$. In the four-band tunneling case, the transmission decreases in $T^+_+$, $T^-_+$ and $T^-_-$ channels in comparison with the single barrier case. It does, however, increase for $T^+_-$ when compared to the single barrier case. Transmission is suppressed in the gap region when an interlayer bias is introduced. This is reflected in the total conductance $G_{\text{tot}}$ in the region of zero conductance. Our results are relevant for electron confinement in AB bilayer graphene and for the development of graphene-based transistors.

Majorana bound state parity exchanges in planar Josephson junctions
Varsha Subramanyan, Jukka I Vayrynen, Alex Levchenko, Smitha Vishveshwara
arXiv:2303.02221v2 Announce Type: replace Abstract: We describe a scheme to exchange fermion parity between two pairs of Majorana bound states mediated by coupling with a centralized quantum dot. We specifically formulate such a scheme for Majorana bound states nucleated in the Josephson vortices formed in a four-fold crossroads junction of planar topological superconductors in the presence of a perpendicular magnetic field. This platform yields several advantages to the execution of our scheme as compared to similar ideas proposed in wire geometries, including control over the positions of the MBS and hence, a tunable coupling with the quantum dot. We show that moving the MBS along the junctions through voltage pulses can facilitate parity exchange via a two-step process, with intermediate projective measurements of the quantum dot charge. Thus, we formulate a way to achieve single qubit operations for MBS in extended Josephson junctions through projective measurements of quantum dot charge. We also discuss the physical viability of our scheme with a particular focus on changes in quantum dot energy levels as a measurable indicator of the success of the scheme.

Charge order induced Dirac pockets in the nonsymmorphic crystal TaTe$_4$
Yichen Zhang, Ruixiang Zhou, Hanlin Wu, Ji Seop Oh, Sheng Li, Jianwei Huang, Jonathan D. Denlinger, Makoto Hashimoto, Donghui Lu, Sung-Kwan Mo, Kevin F. Kelly, Gregory T. McCandless, Julia Y. Chan, Robert J. Birgeneau, Bing Lv, Gang Li, Ming Yi
arXiv:2304.00425v4 Announce Type: replace Abstract: The interplay between charge order (CO) and nontrivial band topology has spurred tremendous interest in understanding topological excitations beyond the single-particle description. In a quasi-one-dimensional nonsymmorphic crystal TaTe$_4$, the (2a$\times$2b$\times$3c) charge ordered ground state drives the system into a space group where the symmetry indicator features the emergence of Dirac fermions and unconventional double Dirac fermions. Using angle-resolved photoemission spectroscopy and first-principles calculations, we provide evidence of the CO induced Dirac fermion-related bands near the Fermi level. Furthermore, the band folding at the Fermi level is compatible with the new periodicity dictated by the CO, indicating that the electrons near the Fermi level follow the crystalline symmetries needed to host double Dirac fermions in this system.

The dynamical structure factor of the SU(4) algebraic spin liquid on the honeycomb lattice
D\'aniel V\"or\"os, Karlo Penc
arXiv:2306.16242v2 Announce Type: replace Abstract: We compute the momentum resolved dynamical spin structure factor $S(k,\omega)$ of the SU(4) Heisenberg model on the honeycomb lattice assuming the $\pi$-flux Dirac spin liquid ground state by two methods: (i) variationally using Gutzwiller projected particle-hole excitations of the $\pi$-flux Fermi sea and (ii) in the non-interacting parton mean-field picture. The two approaches produce qualitatively similar results. Based on this analogy, we argue that the energy spectrum of the projected excitations is a gapless continuum of fractional excitations. Quantitatively, the Gutzwiller projection shifts the weight from higher to lower energies, thus emphasizing the lower edge of the continuum. In the mean-field approach, we obtained the $1/\text{distance}^4$ decay of the spin correlation function, and the local correlations show $S^{33}_{\text{MF}}(\omega)\propto \omega^3$ behavior.

Deconfined quantum criticality lost
Menghan Song, Jiarui Zhao, Meng Cheng, Cenke Xu, Michael M. Scherer, Lukas Janssen, Zi Yang Meng
arXiv:2307.02547v3 Announce Type: replace Abstract: Over the past two decades, the enigma of the deconfined quantum critical point (DQCP) has attracted broad attention across the condensed matter, quantum field theory, and high-energy physics communities, as it is expected to offer a new paradigm in theory, experiment, and numerical simulations that goes beyond the Landau-Ginzburg-Wilson framework of symmetry breaking and phase transitions. However, the nature of DQCP has been controversial. For instance, in the square-lattice spin-1/2 $J$-$Q$ model, believed to realize the DQCP between N\'eel and valence bond solid states, conflicting results, such as first-order versus continuous transition, and critical exponents incompatible with conformal bootstrap bounds, have been reported. The enigma of DQCP is exemplified in its anomalous logarithmic subleading contribution in its entanglement entropy (EE), which was discussed in recent studies. In the current work, we demonstrate that similar anomalous logarithmic behavior persists in a class of models analogous to the DQCP. We systematically study the quantum EE of square-lattice SU($N$) DQCP spin models. Based on large-scale quantum Monte Carlo computation of the EE, we show that for a series of $N$ smaller than a critical value, the anomalous logarithmic behavior always exists in the EE, which implies that the previously determined DQCPs in these models do not belong to conformal fixed points. In contrast, when $N\ge N_c$ with a finite $N_c$ that we evaluate to lie between $7$ and $8$, the DQCPs are consistent with conformal fixed points that can be understood within the Abelian Higgs field theory with $N$ complex components.

Chiral Quantum well Rashba splitting in Sb monolayer on Au(111)
Jinbang Hu, Lina Liu, Xiansi Wang, Yong P. Chen, Justin W Wells
arXiv:2308.06814v3 Announce Type: replace Abstract: We present atomic and electronic structure investigations of Single-layer Sb(110) rhombohedral crystal formed on Au(111) substrate. Low energy electron diffraction (LEED) and scanning tunneling microscopy (STM) reveal a pure 2D Sb stripe structure, composed by a pair of Sb(110) unit cell located in a chiral configuration with mirror symmetry broken along the x axis direction. Based on angle-resolved photoemission spectroscopy (ARPES) measurement and Sb-weighted band structure from density functional theory calculations, we report the unambiguous determination of one pair of Rashba-type splitting band from the 2D Sb film, exhibiting a chiral symmetry in the electronic structure with the crossing point located at point and point, respectively. Moreover, From dI/dV spectra and calculated density of states(DOS), the quantum well(QW) Rashba-type states at different energy induced by the in-plane mirror symmetry broken in Sb stripe structure have been identified, and the orbital decomposition of projected band structure indicates hybridization between Sb py state and Au state can modify the spin splitting of QW states due to the intrinsic large SOC of Au state introduced into the QW states.

The effect of surface oxidation and crystal thickness on magnetic properties and magnetic domain structures of Cr2Ge2Te6
Joachim Dahl Thomsen, Myung-Geun Han, Aubrey Penn, Alexandre C. Foucher, Michael Geiwitz, Kenneth S. Burch, Luk\'a\v{s} D\v{e}kanovsk\'y, Zden\v{e}k Sofer, Yu Liu, Cedomir Petrovic, Frances M. Ross, Yimei Zhu, Prineha Narang
arXiv:2310.02319v2 Announce Type: replace Abstract: Van der Waals (vdW) magnetic materials such as Cr2Ge2Te6 (CGT) show promise for novel memory and logic applications. This is due to their broadly tunable magnetic properties and the presence of topological magnetic features such as skyrmionic bubbles. A systematic study of thickness and oxidation effects on magnetic domain structures is important for designing devices and vdW heterostructures for practical applications. Here, we investigate thickness effects on magnetic properties, magnetic domains, and bubbles in oxidation-controlled CGT crystals. We find that CGT exposed to ambient conditions for 5 days forms an oxide layer approximately 5 nm thick. This oxidation leads to a significant increase in the oxidation state of the Cr ions, indicating a change in local magnetic properties. This is supported by real space magnetic texture imaging through Lorentz transmission electron microscopy. By comparing the thickness dependent saturation field of oxidized and pristine crystals, we find that oxidation leads to a non-magnetic surface layer which is thicker than the oxide layer alone. We also find that the stripe domain width and skyrmionic bubble size are strongly affected by the crystal thickness in pristine crystals. These findings underscore the impact of thickness and surface oxidation on the properties of CGT such as saturation field and domain/skyrmionic bubble size and suggest a pathway for manipulating magnetic properties through a controlled oxidation process.

Long-Range Structural Order in a Hidden Phase of Ruddlesden-Popper Bilayer Nickelate La$_3$Ni$_2$O$_7$
Haozhe Wang, Long Chen, Aya Rutherford, Haidong Zhou, Weiwei Xie
arXiv:2312.09200v2 Announce Type: replace Abstract: The recent discovery of superconductivity in Ruddlesden-Popper bilayer nickelate, specifically La$_3$Ni$_2$O$_7$, has generated significant interest in the exploration of high-temperature superconductivity within this material family. In this study, we present the crystallographic and electrical resistivity properties of two distinct Ruddlesden-Popper nickelates: the bilayer La$_3$Ni$_2$O$_7$ (referred to as 2222-phase) and a previously uncharacterized phase, La$_3$Ni$_2$O$_7$ (1313-phase). The 2222-phase is characterized by a pseudo $F$-centered orthorhombic lattice, featuring bilayer perovskite [LaNiO$_3$] layers interspaced by rock salt [LaO] layers, forming a repeated ...2222... sequence. Intriguingly, the 1313-phase, which displays semiconducting properties, crystallizes in the $Cmmm$ space group and exhibits a pronounced predilection for a $C$-centered orthorhombic lattice. Within this structure, the perovskite [LaNiO$_3$] layers exhibit a distinctive long-range ordered arrangement, alternating between single- and trilayer configurations, resulting in a ...1313... sequence. This report contributes to novel insights into the crystallography and the structure-property relationship of Ruddlesden-Popper nickelates, paving the way for further investigations into their unique physical properties.

Persistent homology and topological statistics of hyperuniform point clouds
Marco Salvalaglio, Dominic J. Skinner, J\"orn Dunkel, Axel Voigt
arXiv:2401.13123v2 Announce Type: replace Abstract: Hyperuniformity, the suppression of density fluctuations at large length scales, is observed across a wide variety of domains, from cosmology to condensed matter and biological systems. Although the standard definition of hyperuniformity only utilizes information at the largest scales, hyperuniform configurations have distinctive local characteristics. However, the influence of global hyperuniformity on local structure has remained largely unexplored; establishing this connection can help uncover long-range interaction mechanisms and detect hyperuniform traits in finite-size systems. Here, we study the topological properties of hyperuniform point clouds by characterizing their persistent homology and the statistics of local graph neighborhoods. We find that varying the structure factor results in configurations with systematically different topological properties. Moreover, these topological properties are conserved for subsets of hyperuniform point clouds, establishing a connection between finite-sized systems and idealized reference arrangements. Comparing distributions of local topological neighborhoods reveals that the hyperuniform arrangements lie along a primarily one-dimensional manifold reflecting an order-to-disorder transition via hyperuniform configurations. The results presented here complement existing characterizations of hyperuniform phases of matter, and they show how local topological features can be used to detect hyperuniformity in size-limited simulations and experiments.

New insights into the origin of the first sharp diffraction peak in amorphous silica from an analysis of chemical and radial ordering
Parthapratim Biswas, Devilal Dahal, Stephen R. Elliott
arXiv:2403.10632v2 Announce Type: replace Abstract: The structural origin of the first sharp diffraction peak (FSDP) in amorphous silica is studied by analyzing chemical and radial ordering of silicon (Si) and oxygen (O) atoms in binary amorphous networks. The study shows that the chemical order involving Si--O and O--O pairs play a major role in the formation of the FSDP in amorphous silica. This is supplemented by small contributions arising from the relatively weak Si--Si correlations in the Fourier space. A shell-by-shell analysis of the radial correlations between Si--Si, Si--O and O--O atoms in the network reveals that the position and the intensity of the FSDP are largely determined by atomic pair correlations originating from the first two/three radial shells on a length scale of about 5--8 {\AA}, whereas the fine structure of the intensity curve in the vicinity of the FSDP is perturbatively modified by atomic correlations arising from the radial shells beyond 8 {\AA}. The study leads to a simple mathematical relationship between the position of the radial peaks ($r_k$) in the partial pair-correlation functions and the diffraction peaks ($Q_k$) that can be used to obtain approximate positions of the FSDP and the principal peak. The results are complemented by numerical calculations and an accurate semi-analytical expression for the diffraction intensity obtained from the partial pair-correlation functions of amorphous silica for a given radial shell.

Topology reconstruction for asymmetric systems by isomorphic mapping or perturbation approximation
Yunlin Li, Jingguang Chen, Xingchao Qi, Langlang Xiong, Xianjun Wang, Yufu Liu, Fang Guan, Lei Shi, Xunya Jiang
arXiv:2403.12104v3 Announce Type: replace Abstract: The systems without symmetries, e.g. the spatial and chiral symmetries, are generally thought to be improper for topological study and no conventional integral topological invariant can be well defined. In this work, with multi-band asymmetric Rice-Mele-like systems as examples, for the first time we show that the topology of all gaps can be reconstructed by two general methods and topological origin of many phenomena are revealed. A new integral topological invariant, i.e. the renormalized real-space winding number, can properly characterize the topology and bulk-edge correspondence of such systems. For the first method, an isomorphic mapping relationship between a Rice-Mele-like system and its chiral counterpart is set up, which accounts for the topology reconstruction in the half-filling gaps. For the second method, the Hilbert space of asymmetric systems could be reduced into degenerate subspaces by perturbation approximation, so that the topology in subspaces accounts for the topology reconstruction in the fractional-filling gaps. Surprisingly, the topology reconstructed by perturbation approximation exhibits extraordinary robustness since the topological edge states even exist far beyond the weak perturbation limit. We also show that both methods can be widely used for other asymmetric systems, e.g. the two-dimensional (2D) Rice-Mele systems and the superconductor systems. At last, for the asymmetric photonic systems, we predict different topological edge states by our topology-reconstruction theory and experimentally observe them in the laboratory, which agrees with each other very well. Our findings open a door for investigating new topological phenomena in asymmetric systems by various topological reconstruction methods which should greatly expand the category of topology study.

Quantum Monte Carlo study of thin parahydrogen films on graphite
Jieru Hu, Massimo Boninsegni
arXiv:2403.12637v2 Announce Type: replace Abstract: The low-temperature properties of one and two layers of parahydrogen adsorbed on graphite are investigated theoretically through Quantum Monte Carlo simulations. We adopt a microscopic model that explicitly includes the corrugation of the substrate. We study the phase diagram of a monolayer up to second layer promotion, and the possible occurrence of superfluidity in the second layer. We obtain results down to a temperature as low as 8 mK. We find second-layer promotion to occur at a considerably greater coverage than obtained in previous calculations and estimated experimentally; moreover, we find no evidence of a possible finite superfluid response in the second layer, disproving recent theoretical predictions.

Elevated temperature effects (T > 100 {\deg}C) on the interfacial water and microstructure swelling of Na-montmorillonite
Wei Qiang Chen, Majid Sedighi, Florent Curvalle, Andrey P Jivkov
arXiv:2310.06377v2 Announce Type: replace-cross Abstract: Montmorillonite-based barriers are key elements of the engineered barrier systems (EBS) in geological disposal facilities (GDF). Their performance at temperatures above 100 {\deg}C is not sufficiently understood to assess the possibility of raising the temperature limits in GDF designs that could reduce construction costs and CO2 footprint. The present work provides new fundamental insights through molecular dynamics (MD) simulations of Na-montmorillonite's water-clay interactions and swelling pressure at temperatures 298-500 K and basal spacings of 1.5-3.5 nm. At temperatures above 100 {\deg}C, the swelling behaviour is governed by the attractive van der Waals force and the repulsive hydration force instead of the repulsive electrostatic (double layer) force. The swelling pressure reduction with increasing temperature is related to the weakened hydration repulsion and electric double layer repulsion, which result from the deterioration of the interlayer water layer structure and the shrinkage of the electric double layer. The applicability and breakdown of the classic Derjaguin-Landau-Verwey-Overbeek (DLVO) theory at elevated temperatures are examined. By excluding the osmotic contribution in the DLVO theory, the summation of the van der Waals interaction in DLVO and an additional non-DLVO hydration interaction can predict our MD system's swelling under high temperatures. The findings of this study provide a fundamental understanding of the swelling behaviour and the underlying molecular-level mechanisms of the clay microstructure under extreme conditions.

Topology and entanglement of molecular phase space
Victor V. Albert, Eric Kubischta, Mikhail Lemeshko, Lee R. Liu
arXiv:2403.04572v2 Announce Type: replace-cross Abstract: We formulate a quantum phase space for molecular rotational and nuclear-spin states. Taking in molecular geometry and nuclear-spin data, our framework yields admissible position and momentum states, inter-convertible via a generalized Fourier transform. We classify molecules into three types -- asymmetric, rotationally symmetric, and perrotationally symmetric -- with the last type having no macroscopic analogue due to nuclear-spin statistics constraints. We identify two features in perrotationally symmetric state spaces that are Hamiltonian-independent and induced solely by symmetry and spin statistics. First, many molecular species are intrinsically rotation-spin entangled in a way that cannot be broken without transitioning to another species or breaking symmetry. Second, each molecular position state houses an internal pseudo-spin or "fiber" degree of freedom, and the fiber's Berry phase or matrix after adiabatic changes in position yields naturally robust operations, akin to braiding anyonic quasiparticles or realizing fault-tolerant quantum gates. We outline scenarios where these features can be experimentally probed.

$^{13}$C Hyperpolarization with Nitrogen-Vacancy Centers in Micro- and Nanodiamonds for Sensitive Magnetic Resonance Applications
R\'emi Blinder, Yuliya Mindarava, Martin Korzeczek, Alastair Marshall, Felix Gl\"ockler, Steffen Nothelfer, Alwin Kienle, Christian Laube, Wolfgang Knolle, Christian Jentgens, Martin B. Plenio, Fedor Jelezko
arXiv:2403.14521v2 Announce Type: replace-cross Abstract: Nuclear hyperpolarization is a known method to enhance the signal in nuclear magnetic resonance (NMR) by orders of magnitude. The present work addresses the $^{13}$C hyperpolarization in diamond micro- and nanoparticles, using the optically-pumped nitrogen-vacancy center (NV) to polarize $^{13}$C spins at room temperature. Consequences of the small particle size are mitigated by using a combination of surface treatment improving the $^{13}$C relaxation ($T_1$) time, as well as that of NV, and applying a technique for NV illumination based on a microphotonic structure. Monitoring the light-induced redistribution of the NV spin state populations with electron paramagnetic resonance, a strong polarization enhancement for the NV spin state is observed in a narrow spectral region corresponding to about 4\% of these defect centers. By combining adjustments to the `PulsePol' sequence and slow sample rotation, the NV-$^{13}$C polarization transfer rate is improved further. The hyperpolarized $^{13}$C NMR signal is observed in particles of 2 $\mu$m and 100 nm median sizes, with enhancements over the thermal signal (at 0.29 T magnetic field), of 1500 and 940, respectively. The present demonstration of room-temperature hyperpolarization anticipates the development of agents based on nanoparticles for sensitive magnetic resonance applications.

Found 8 papers in prb
Date of feed: Tue, 26 Mar 2024 04:16:58 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

Proximity effect of $s$-wave superconductor on an inversion-broken Weyl semimetal
Robert Dawson and Vivek Aji
Author(s): Robert Dawson and Vivek Aji

Inducing superconductivity in systems with unconventional band structures is a promising approach for realizing unconventional superconductivity. Of particular interest are single-interface or Josephson junction architectures involving Weyl semimetals (WSM), which are predicted to host odd-parity, p…

[Phys. Rev. B 109, 094517] Published Mon Mar 25, 2024

Complete zero-energy flat bands of surface states in fully gapped chiral noncentrosymmetric superconductors
Clara J. Lapp, Julia M. Link, and Carsten Timm
Author(s): Clara J. Lapp, Julia M. Link, and Carsten Timm

Flat bands of surface states in noncentrosymmetric superconductors accompanied by a full gap in the bulk would be an alternative route to a strongly interacting two-dimensional Fermi system. They could provide a robust platform for quantum computation. Here, the authors explore a way to stabilize such bands in the entire surface Brillouin zone by introducing an additional spin-rotation symmetry that forces the direction of the spin-orbit-coupling vector not to depend on the momentum component, normal to the surface.

[Phys. Rev. B 109, 104521] Published Mon Mar 25, 2024

Observation of anomalous nonequilibrium terahertz dynamics and a gapped topological phase in a semimetal $\mathrm{CaIr}{\mathrm{O}}_{3}$ thin film
K. Santhosh Kumar, Monu Kinha, Anagha P., Rahul Dagar, Siddharth Sharma, Dasarath Swaraj, and D. S. Rana
Author(s): K. Santhosh Kumar, Monu Kinha, Anagha P., Rahul Dagar, Siddharth Sharma, Dasarath Swaraj, and D. S. Rana

Understanding the effects of coexisting electron correlations and spin-orbit coupling on the electronic ground state is the crux of emergent quantum phenomena in complex oxide systems. Here, we explore the critical role of such host interactions on the semimetallic state in $\mathrm{CaIr}{\mathrm{O}…

[Phys. Rev. B 109, 115150] Published Mon Mar 25, 2024

Modulating dichroism and optical conductivity in bilayer graphene under intense electromagnetic field irradiation
S. Sajad Dabiri, Hosein Cheraghchi, Fatemeh Adinehvand, and Reza Asgari
Author(s): S. Sajad Dabiri, Hosein Cheraghchi, Fatemeh Adinehvand, and Reza Asgari

This study explores the impact of a strong perpendicular laser field on the electronic structure and optical conductivity of bilayer graphene. Employing the Floquet-Bloch theorem and a four-band Hamiltonian model, we calculate the optical conductivity, unveiling modified optical properties due to th…

[Phys. Rev. B 109, 115431] Published Mon Mar 25, 2024

Symbolic determinant construction of perturbative expansions
Ibsal Assi and J. P. F. LeBlanc
Author(s): Ibsal Assi and J. P. F. LeBlanc

We present a symbolic algorithm for the fully analytic treatment of perturbative expansions of Hamiltonians with general two-body interactions. The method merges well-known analytics with the recently developed symbolic integration tool, algorithmic Matsubara integration, that allows for the evaluat…

[Phys. Rev. B 109, 125143] Published Mon Mar 25, 2024

Variational Monte Carlo approach for the Hubbard model applied to twisted bilayer ${\mathrm{WSe}}_{2}$ at half-filling
A. Biborski, P. Wójcik, and M. Zegrodnik
Author(s): A. Biborski, P. Wójcik, and M. Zegrodnik

We consider an effective Hubbard model with spin- and direction-dependent complex hoppings $t$, applied to twisted homobilayer ${\mathrm{WSe}}_{2}$ using a variational Monte Carlo approach. The electronic correlations are taken into account by applying the Gutzwiller on-site correlator as well as lo…

[Phys. Rev. B 109, 125144] Published Mon Mar 25, 2024

Unconventional optical response in monolayer graphene due to dominant intraband scattering
Palash Saha and Bala Murali Krishna Mariserla
Author(s): Palash Saha and Bala Murali Krishna Mariserla

Scattering dynamics influences the graphene's transport properties and inhibits the charge carrier deterministic behavior. The intra/interband scattering mechanisms are vital for graphene's optical conductivity response under specific considerations of doping. In this study, we systematically explor…

[Phys. Rev. B 109, 125428] Published Mon Mar 25, 2024

Anomalous Floquet Anderson insulator in a continuously driven optical lattice
Arijit Dutta, Efe Sen, Jun-Hui Zheng, Monika Aidelsburger, and Walter Hofstetter
Author(s): Arijit Dutta, Efe Sen, Jun-Hui Zheng, Monika Aidelsburger, and Walter Hofstetter

The anomalous Floquet Anderson insulator (AFAI) has been theoretically predicted in stepwise periodically driven models, but its stability under more general driving protocols has not been determined. We show that adding disorder to the anomalous Floquet topological insulator realized with a continu…

[Phys. Rev. B 109, L121114] Published Mon Mar 25, 2024

Found 4 papers in prl
Date of feed: Tue, 26 Mar 2024 04:16:58 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

Realizing Synthetic Dimensions and Artificial Magnetic Flux in a Trapped-Ion Quantum Simulator
Y. Wang, Y.-K. Wu, Y. Jiang, M.-L. Cai, B.-W. Li, Q.-X. Mei, B.-X. Qi, Z.-C. Zhou, and L.-M. Duan
Author(s): Y. Wang, Y.-K. Wu, Y. Jiang, M.-L. Cai, B.-W. Li, Q.-X. Mei, B.-X. Qi, Z.-C. Zhou, and L.-M. Duan

Synthetic dimension is a potent tool in quantum simulation of topological phases of matter. Here we propose and demonstrate a scheme to simulate an anisotropic Harper-Hofstadter model with controllable magnetic flux on a two-leg ladder using the spin and motional states of a single trapped ion. We v…

[Phys. Rev. Lett. 132, 130601] Published Mon Mar 25, 2024

Arcsine Laws of Light
V. G. Ramesh, K. J. H. Peters, and S. R. K. Rodriguez
Author(s): V. G. Ramesh, K. J. H. Peters, and S. R. K. Rodriguez

We demonstrate that the time-integrated light intensity transmitted by a coherently driven resonator obeys Lévy’s arcsine laws—a cornerstone of extreme value statistics. We show that convergence to the arcsine distribution is algebraic, universal, and independent of nonequilibrium behavior due to no…

[Phys. Rev. Lett. 132, 133801] Published Mon Mar 25, 2024

Lossless Spin-Orbit Torque in Antiferromagnetic Topological Insulator ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$
Junyu Tang and Ran Cheng
Author(s): Junyu Tang and Ran Cheng

We formulate and quantify the spin-orbit torque (SOT) in intrinsic antiferromagnetic topological insulator ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$ of a few septuple-layer thick in charge-neutral condition, which exhibits pronounced layer-resolved characteristics and even-odd contrast. Contrary to tra…

[Phys. Rev. Lett. 132, 136701] Published Mon Mar 25, 2024

Goldilocks Fluctuations: Dynamic Constraints on Loop Formation in Scale-Free Transport Networks
Radost Waszkiewicz, John Burnham Shaw, Maciej Lisicki, and Piotr Szymczak
Author(s): Radost Waszkiewicz, John Burnham Shaw, Maciej Lisicki, and Piotr Szymczak

Adaptive transport networks are known to contain loops when subject to hydrodynamic fluctuations. However, fluctuations are no guarantee that a loop will form, as shown by loop-free networks driven by oscillating flows. We provide a complete stability analysis of the dynamical behavior of any loop f…

[Phys. Rev. Lett. 132, 137401] Published Mon Mar 25, 2024

Found 2 papers in pr_res
Date of feed: Tue, 26 Mar 2024 04:16:57 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

Atomic excitation trapping in dissimilar chirally coupled atomic arrays
I Gusti Ngurah Yudi Handayana, Chun-Chi Wu, Sumit Goswami, Ying-Cheng Chen, and H. H. Jen
Author(s): I Gusti Ngurah Yudi Handayana, Chun-Chi Wu, Sumit Goswami, Ying-Cheng Chen, and H. H. Jen

An atomic array coupled to a one-dimensional nanophotonic waveguide allows photon-mediated dipole-dipole interactions and nonreciprocal decay channels. Such an array possesses many intriguing quantum phenomena due to its distinctive and emergent quantum correlations. In this atom-waveguide quantum s…

[Phys. Rev. Research 6, 013320] Published Mon Mar 25, 2024

Tailoring coupled topological corner states in photonic crystals via symmetry breaking induced by defects
Zhaojian Zhang, Junbo Yang, and Zhihao Lan
Author(s): Zhaojian Zhang, Junbo Yang, and Zhihao Lan

In this paper, we present an effective approach to tailor the optical properties of coupled corner states in photonic crystal (PhC) supercell arrays by symmetry breaking. Defects are strategically introduced into unit cells to break the in-plane ${C}_{4v}$ symmetry, and numerical simulations confirm…

[Phys. Rev. Research 6, 013321] Published Mon Mar 25, 2024

Found 1 papers in nano-lett
Date of feed: Mon, 25 Mar 2024 13:13:40 GMT

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

[ASAP] Large and Pressure-Dependent c-Axis Piezoresistivity of Highly Oriented Pyrolytic Graphite near Zero Pressure
Bingjie Wang, Juyao Li, Zheng Fang, Yifan Jiang, Shuo Li, Fangyuan Zhan, Zhaohe Dai, Qing Chen, and Xianlong Wei

TOC Graphic

Nano Letters
DOI: 10.1021/acs.nanolett.4c00687

Found 1 papers in acs-nano
Date of feed: Mon, 25 Mar 2024 13:09:59 GMT

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[ASAP] Built-in Electric Field Promotes Interfacial Adsorption and Activation of CO2 for C1 Products over a Wide Potential Window
Xin Zhao, Qingguo Feng, Mengjie Liu, Yuchao Wang, Wei Liu, Danni Deng, Jiabi Jiang, Xinran Zheng, Longsheng Zhan, Jinxian Wang, Huanran Zheng, Yu Bai, Yingbi Chen, Xiang Xiong, and Yongpeng Lei

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ACS Nano
DOI: 10.1021/acsnano.4c01190

Found 1 papers in sci-rep

Search terms: (topolog[a-z]+)|(graphit[a-z]+)|(rhombohedr[a-z]+)|(graphe[a-z]+)|(chalcog[a-z]+)|(landau)|(weyl)|(dirac)|(STM)|(scan[a-z]+ tunne[a-z]+ micr[a-z]+)|(scan[a-z]+ tunne[a-z]+ spectr[a-z]+)|(scan[a-z]+ prob[a-z]+ micr[a-z]+)|(MoS.+\d+|MoS\d+)|(MoSe.+\d+|MoSe\d+)|(MoTe.+\d+|MoTe\d+)|(WS.+\d+|WS\d+)|(WSe.+\d+|WSe\d+)|(WTe.+\d+|WTe\d+)|(Bi\d+Rh\d+I\d+|Bi.+\d+.+Rh.+\d+.+I.+\d+.+)|(BiTeI)|(BiTeBr)|(BiTeCl)|(ZrTe5|ZrTe.+5)|(Pt2HgSe3|Pt.+2HgSe.+3)|(jacuting[a-z]+)|(flatband)|(flat.{1}band)|(LK.{1}99)

Potential toxicity of graphene (oxide) quantum dots via directly covering the active site of anterior gradient homolog 2 protein
Yaoxing Huang

Scientific Reports, Published online: 26 March 2024; doi:10.1038/s41598-024-57677-9

Potential toxicity of graphene (oxide) quantum dots via directly covering the active site of anterior gradient homolog 2 protein