Found 48 papers in cond-mat

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Intertwined Magnetism and Superconductivity in Isolated Correlated Flat Bands
Xuepeng Wang, J. F. Mendez-Valderrama, Johannes S. Hofmann, Debanjan Chowdhury
arXiv:2402.09506v1 Announce Type: new Abstract: Multi-orbital electronic models hosting a non-trivial band-topology in the regime of strong electronic interactions are an ideal playground for exploring a host of complex phenomenology. We consider here a sign-problem-free and time-reversal symmetric model with isolated topological (chern) bands involving both spin and valley degrees of freedom in the presence of a class of repulsive electronic interactions. Using a combination of numerically exact quantum Monte Carlo computations and analytical field-theoretic considerations we analyze the phase-diagram as a function of the flat-band filling, temperature and relative interaction strength. The low-energy physics is described in terms of a set of intertwined orders -- a spin-valley hall (SVH) insulator and a spin-singlet superconductor (SC). Our low-temperature phase diagram can be understood in terms of an effective SO(4) pseudo-spin non-linear sigma model. Our work paves the way for building more refined and minimal models of realistic materials, including moir\'e systems, to study the universal aspects of competing insulating phases and superconductivity in the presence of non-trivial band-topology.

Kennedy-Tasaki transformation and non-invertible symmetry in lattice models beyond one dimension
Aswin Parayil Mana, Yabo Li, Hiroki Sukeno, Tzu-Chieh Wei
arXiv:2402.09520v1 Announce Type: new Abstract: We give an explicit operator representation (via a sequential circuit and projection to symmetry subspaces) of Kramers-Wannier duality transformation in higher-dimensional subsystem symmetric models generalizing the construction in the 1D transverse-field Ising model. Using the Kramers-Wannier duality operator, we also construct the Kennedy-Tasaki transformation that maps subsystem symmetry-protected topological phases to spontaneous subsystem symmetry breaking phases, where the symmetry group for the former is either $\mathbb{Z}_2\times\mathbb{Z}_2$ or $\mathbb{Z}_2$. This generalizes the recently proposed picture of one-dimensional Kennedy-Tasaki transformation as a composition of manipulations involving gauging and stacking symmetry-protected topological phases to higher dimensions.

Electron Interference as a Probe of Majorana Zero Modes
Nadav Drechsler, Omri Lesser, Yuval Oreg
arXiv:2402.09525v1 Announce Type: new Abstract: Detecting Majorana zero modes (MZMs) in topological superconductors remains challenging, as localized non-topological states can mimic MZM signatures. Here, we propose electron interferometry by non-local transport measurements as a definitive probe to distinguish MZMs from non-topological states. We develop an analytical minimal model showing that interference via two MZMs exhibits a robust pattern, in contrast to a non-topological system. We then numerically confirm this using various topological superconductor models. We find that MZMs are characterized by an interference pattern that is insensitive to various perturbations, such as electrostatic gate potential, and resilient to disorder. Our proposed interferometry approach offers an experimentally accessible means to detect MZMs, probing their underlying nature through a universal response.

Selective Hydrogenation Promotes Anisotropic Thermoelectric Properties of TPDH-Graphene
Caique Campos de Oliveira, Douglas Soares Galvao, Pedro Alves da Silva Autreto
arXiv:2402.09572v1 Announce Type: new Abstract: We have combined DFT calculations with the Boltzmann semiclassical transport theory to investigate the effect of selective hydrogenation on the thermoelectric properties of tetra-penta-deca-hexagonal graphene (TPDH-gr), a recently proposed new 2D carbon allotrope. Our results show that the Seebeck coefficient is enhanced after hydrogenation. The conductivity along the x direction is increased almost eight times while being almost suppressed along the y direction. This behavior can be understood in terms of the electronic structure changes due to the appearance of a Dirac-like cone after the selective hydrogenation. Consistent with the literature, the electronic contribution to thermal conductivity displays the same qualitative behavior as the conductivity, as expected from the Wiedemann-Franz law. The increase in thermal conductivity with temperature limits the material's power factor. The significant increase in the Seebeck coefficient and conductivity increases also contribute to the thermal conductivity increase. These results show that hydrogenation is an effective method to improve the TPDH-gr thermoelectric properties, and this carbon allotrope can be an effective material for thermoelectric applications.

Simple realization of a fragile topological lattice with quasi flat-bands in a microcavity array
Yuhui Wang, Shupeng Xu, Liang Feng, Ritesh Agarwal
arXiv:2402.09665v1 Announce Type: new Abstract: Topological flat bands (TFBs) are increasingly recognized as an important paradigm to study topological effects in the context of strong correlation physics. As a representative example, recently it has been theoretically proposed that the topological non-triviality offers a unique contribution to flat-band superconductivity, which can potentially lead to a higher critical temperature of superconductivity phase transition. Nevertheless, the topological effects within flat bands in bosonic systems, specifically in the context of Bose-Einstein condensation (BEC), are less explored. It has been shown theoretically that non-trivial topological and geometric properties will also have a significant influence in bosonic condensates as well. However, potential experimental realizations have not been extensively studied yet. In this work, we introduce a simple photonic lattice from coupled Kagome and triangular lattices designed based on topological quantum chemistry theory, which supports topologically nontrivial quasi-flat bands. Besides band representation analysis, the non-triviality of these quasi-flat bands is also confirmed by Wilson loop spectra which exhibit winding features. We further discuss the corresponding experimental realization in a microcavity array for future study supporting the potential extension to condensed exciton-polaritons. Notably, we showed that the inevitable in-plane longitudinal-transverse polarization splitting in optical microcavities will not hinder the construction of topological quasi-flat bands. This work acts as an initial step to experimentally explore the physical consequence of non-trivial topology and quantum geometry in quasi-flat bands in bosonic systems, offering potential channels for its direct observation.

Site-selective cobalt substitution in La-Co co-substituted magnetoplumbite-type ferrites: $^{59}$Co-NMR and DFT calculation study
Hiroyuki Nakamura, Hiroto Ohta, Ryuya Kobayashi, Takeshi Waki, Yoshikazu Tabata, Hidekazu Ikeno, Christian M\'eny
arXiv:2402.09706v1 Announce Type: new Abstract: The La-Co co-substituted magnetoplumbite-type (M-type) ferrites $A$Fe$_{12}$O$_{19}$ ($A$ = Ca, Sr and Ba, ion sizes Ca$^{2+}$ $<$ Sr$^{2+}$ $<$ Ba$^{2+}$) with Co compositions around 0.2 have been subjected to $^{59}$Co-NMR. The results show that Co occupies the 4f$_1$, 2a and 12k sites, and that the smaller the $A$ ion, the more Co tends to occupy the 4f$_1$ minority spin site, which is effective in enhancing both uniaxial anisotropy and magnetisation. First-principles total energy calculations based on density functional theory (DFT) of undoped $A$Fe$_{12}$O$_{19}$ and a supercell ($2 \times 2 \times 1$ of the unit cell) in which 1/96 of Fe$^{3+}$ is replaced by Co$^{2+}$ were performed to predict the stable structure and Co occupancy sites. The results show that regardless of $A$, Co is most stable when it occupies the 4f$_1$ site, followed by the 2a and 12k sites with energy differences on the order of 100 meV, and Co practically does not occupy the 2b and 4f$_2$ sites. As the $A$ ion becomes smaller, the energy difference when Co occupies each Fe site tends to increase, and the Co occupancy of the 4f$_1$ site also increases. The site selectivity of Co can be roughly explained as a result of the difference in uniaxial strain along the $c$-axis associated with the difference in $A$. However, the influence of the $A$ ion differs between the R and S blocks and the local strain also has a secondary effect on the Co distribution. Based on these results, the guidelines for improving the performance (anisotropy and magnetisation) of La-Co co-substituted M-type ferrite magnets with a limited amount of Co can be summarised as follows: It is effective to select as small $A$ ions as possible and to post-anneal at low temperature or cool slowly to concentrate Co at the 4f$_1$ site in tetrahedral coordination.

Dimension-Dependent Critical Scaling Analysis and Emergent Competing Interaction Scales in a 2D Van der Waals magnet Cr$_{2}$Ge$_{2}$Te$_{6}$
P. C. Mahato, Suprotim Saha, Bikash Das, Subhadeep Datta, Rajib Mondal, Sourav Mal, Ashish Garg, Prasenjit Sen, S. S. Banerjee
arXiv:2402.09741v1 Announce Type: new Abstract: We investigate thickness-dependent transformation from a paramagnetic to ferromagnetic phase in Cr$_{2}$Ge$_{2}$Te$_{6}$ (CGT) in bulk and few-layer flake forms. 2D Ising-like critical transition in bulk CGT occurs at $T_{c}$ = 67 K with out-of-plane magnetic anisotropy. Few-layer CGT on hBN/SiO$_{2}$/Si substrate displays the same $T_{c}$ but also exhibits a new critical transition at $T^{\prime}_c$ = 14.2 K. Here, critical scaling analysis reveals the critical exponents differ significantly from those in bulk and do not align with the known universality classes. Our Density Functional Theory (DFT) and classical calculations indicate competition between magnetocrystalline and dipolar anisotropy emerges with reduced dimensions. The observed behavior is due to minor structural distortions in low dimensional CGT, which modify the balance between spin-orbit coupling, exchange interactions and dipolar anisotropy. This triggers a critical crossover at $T^{\prime}_c$. Our study shows the emergence of a complex interplay of short- and long-range interactions below $T^{\prime}_c$ as CGT approaches the 2D limit.

Doping induced multiferroicity and quantum anomalous Hall effect in $\alpha$-In$_2$Se$_3$ thin films
Zhiqiang Tian, Jin-Yang Li, Tao Ouyang, Chao-Fei Liu, Ziran Liu, Si Li, Anlian Pan, Mingxing Chen
arXiv:2402.09770v1 Announce Type: new Abstract: In flat-band materials, the strong Coulomb interaction between electrons can lead to exotic physical phenomena. Recently, $\alpha$-In$_2$Se$_3$ thin films were found to possess ferroelectricity and flat bands. In this work, using first-principles calculations, we find that for the monolayer, there is a Weyl point at $\Gamma$ in the flat band, where the inclusion of the spin-orbit coupling opens a gap. Shifting the Fermi level into the spin-orbit gap gives rise to nontrivial band topology, which is preserved for the bilayer regardless of the interlayer polarization couplings. We further calculate the Chern number and edge states for both the monolayer and bilayer, for which the results suggest that they become quantum anomalous Hall insulators under appropriate dopings. Moreover, we find that the doping-induced magnetism for In$_2$Se$_3$ bilayer is strongly dependent on the interlayer polarization coupling. Therefore, doping the flat bands in In$_2$Se$_3$ bilayer can also yield multiferroicity, where the magnetism is electrically tunable as the system transforms between different polarization states. Our study thus reveals that multiferroicity and nontrivial band topology can be unified into one material for designing multifunctional electronic devices.

Electronic properties of MoSe$_2$ nanowrinkles
Stefan Velja, Jannis Krumland, Caterina Cocchi
arXiv:2402.09785v1 Announce Type: new Abstract: Mechanical deformations, either spontaneously occurring during sample preparation or purposely induced in their nanoscale manipulation, drastically affect the electronic and optical properties of transition metal dichalcogenide monolayers. In this first-principles work based on density-functional theory, we shed light on the interplay among strain, curvature, and electronic structure of MoSe$_2$ nanowrinkles. We analyze their structural properties highlighting the effects of coexisting local domains of tensile and compressive strain in the same system. By contrasting the band structures of the nanowrinkles against counterparts obtained for flat monolayers subject to the same amount of strain, we clarify that the specific features of the former, such as the moderate variation of the band-gap size and its persisting direct nature, are ruled by curvature rather than strain. The analysis of the wave-function distribution indicates strain-dependent localization of the frontier states in the conduction region while in the valence the sensitivity to strain is much less pronounced. The discussion about transport properties, based on the inspection of the effective masses, reveals excellent perspectives for these systems as active components for (opto)electronic devices.

Variational Density Functional Perturbation Theory for Metals
Xavier Gonze, Samare Rostami, Christian Tantardini
arXiv:2402.09806v1 Announce Type: new Abstract: Density functional perturbation theory is a well-established method to study responses of molecules and solids, especially responses to atomic displacements or to different perturbing fields (electric, magnetic). Like for density functional theory, the treatment of metals is delicate, due to the Fermi-Dirac statistics and electronic bands crossing the Fermi energy. At zero temperature, there is an abrupt transition from occupied states to unoccupied ones, usually addressed with smearing schemes. Also, at finite temperature, fractional occupations are present, and the occupation numbers may vary in response to the perturbation. The present work establishes the characteristics of density functional perturbation theory stemming from the underlying variational principle, in the case of metals. After briefly reviewing variational density functional theory for metals, the convexity of the entropy function of the occupation number is analyzed, and, at finite temperature, the benefit of resmearing the Fermi-Dirac broadening with the Methfessel-Paxton one is highlighted. Then the variational expressions for the second-order derivative of the free energy are detailed, exposing the different possible gauge choices. The influence of the inaccuracies in the unperturbed wavefunctions from the prior density functional theory calculation is studied. The whole formalism is implemented in the ABINIT software package.

Melting of a vortex matter Wigner crystal
Tyler W. Neely, Guillaume Gauthier, Charles Glasspool, Matthew J. Davis, Matthew T. Reeves
arXiv:2402.09920v1 Announce Type: new Abstract: The two-dimensional One-Component Plasma (OCP) is a foundational model of the statistical mechanics of interacting particles, describing phenomena common to astrophysics, turbulence, and the Fractional Quantum Hall Effect (FQHE). Despite an extensive literature, the phase diagram of the 2D OCP is still a subject of some controversy. Here we develop a "vortex matter" simulator to realize the logarithmic-interaction OCP experimentally by exploiting the topological character of quantized vortices in a thin superfluid layer. Precision optical-tweezer control of the location of quantized vortices enables direct preparation of the OCP ground state with or without defects, and heating from acoustic excitations allows the observation of the melting transition from the solid Wigner crystal through the liquid phase. We present novel theoretical analysis that is in quantitative agreement with experimental observations, and demonstrates how equilibrium states are achieved through the system dynamics. This allows a precise measurement of the superfluid-thermal cloud mutual friction and heating coefficients. This platform provides a route towards solving a number of open problems in systems with long-range interactions. At equilibrium, it could distinguish between the competing scenarios of grain boundary melting and KTHNY theory. Dynamical simulators could test the existence of predicted edge-wave solitons which form a hydrodynamic analogue of topological edge states in the FQHE.

Probing $Ca_3Ti_2O_7$ crystal structure at the atomic level: Insights from $^{111m}Cd/^{111}Cd$ PAC spectroscopy and ab-initio studies
P. Rocha-Rodrigues, I. P. Miranda, S. S. M. Santos, G. N. P. Oliveira, T. Leal, M. L. Marcondes, J. G. Correia, L. V. C. Assali, H. M. Petrilli, J. P. Ara\'ujo, A. M. L. Lopes
arXiv:2402.09945v1 Announce Type: new Abstract: Perturbed angular correlation spectroscopy combined with $ab-initio$ electronic structure calculations is used to unravel the structural phase transition path from the low-temperature polar structure to the high-temperature structural phase in $Ca_3Ti_2O_7$, a hybrid improper ferroelectric. This procedure explores the unique features of a local probe environment approach by monitoring the evolution of the electric field gradient tensor at the calcium sites. The local environments, observed above 1057 K, confirm a structural phase transition from the $A2_1am$ symmetry to an orthorhombic $Acaa$ symmetry in the $Ca_3Ti_2O_7$ crystal lattice, disagreeing with the frequently reported avalanche structural transition from the polar $A2_1am$ phase to the aristotype $I4/mmm$ phase. Moreover, the EFG temperature dependency, within the $A2_1am$ temperature stability, is shown to be sensitive to the recently proposed $Ca_3Ti_2O_7$ ferroelectric polarization decrease within the 500-800~K temperature range.

Optimal design of fast topological pumping
Xianggui Ding, Zongliang Du, Jiachen Luo, Hui Chen, Zhenqun Guan, Xu Guo
arXiv:2402.09958v1 Announce Type: new Abstract: Utilizing synthetic dimensions generated by spatial or temporal modulation, topological pumping enables the exploration of higher-dimensional topological phenomena through lower-dimensional physical systems. In this letter, we propose a rational design paradigm of fast topological pumping based on 1D and 2D time-modulated discrete elastic lattices for the first time. Firstly, the realization of topological pumping is ensured by introducing quantitative indicators to drive a transition of the edge or corner state in the lattice spectrum. Meanwhile, with the help of limiting speed for adiabaticity to calculate the modulation time, a mathematical formulation of designing topological pumping with the fastest modulation speed is presented. By applying the proposed design paradigm, topological edge-bulk-edge and corner-bulk-corner energy transport are successfully achieved, with 11.2 and 4.0 times of improvement in modulation speed compared to classical pumping systems in the literature. In addition, applying to 1D and 2D space-modulated systems, the optimized modulation schemes can reduce the number of stacks to 5.3% and 26.8% of the classical systems while ensuring highly concentrated energy transport. This design paradigm is expected to be extended to the rational design of fast topological pumping in other physical fields.

Exploring 2D Materials by High Pressure Synthesis: hBN, Mg-hBN, b-P, b-AsP, and GeAs
N. D. Zhigadlo
arXiv:2402.10019v1 Announce Type: new Abstract: In materials science, selecting the right synthesis technique for specific compounds is one of the most important steps. High-pressure conditions have a significant effect on the crystal growth processes, leading to the creation of unique structures and properties that usually are not possible under normal conditions. The prime objective of this article is to illustrate the benefits of using high-pressure, high-temperature (HPHT) technique when developing two-dimensional (2D) materials. We could successfully grow bulk single crystals of hexagonal boron nitride (hBN) and magnesium doped hexagonal boron nitride (Mg-hBN) from Mg-B-N solvent. Further exploration of the Mg-B-N system could lead to the crystallization of isotopically 10B and 11B enriched hBN crystals, and other doped variants of it. Black phosphorus (b-P) and black phosphorus doped with arsenic (b-AsP) were obtained by directly converting its elements into melt and subsequently crystallizing them under HPHT. Germanium arsenide (GeAs) bulk single crystals were also obtained from the melt at a pressure of 1 GPa. Upon crystallization, all these compounds exhibit the anticipated layered structures, which makes them easy to exfoliate into 2D flakes, thus providing opportunities to modify their electrical behavior and create new useful devices.

Three-dimensional active nematic turbulence: chirality, flow alignment and elastic anisotropy
Nika Kralj, Miha Ravnik, \v{Z}iga Kos
arXiv:2402.10020v1 Announce Type: new Abstract: Various active materials exhibit strong spatio-temporal variability of their orientational order known as active turbulence, characterised by irregular and chaotic motion of topological defects, including colloidal suspensions, biofilaments, and bacterial colonies. Here, we present a numerical study of three-dimensional (3D) active nematic turbulence, examining the influence of main material constants: (i) the flow-alignment viscosity, (ii) the magnitude and anisotropy of elastic deformation modes (elastic constants), and (iii) the chirality. Specifically, this main parameter space covers contractile or extensile, flow-aligning or flow tumbling, chiral or achiral elastically anisotropic active nematic fluids. The results are presented using time- and space-averaged fields of defect density and mean square velocity. The results also discuss defect density and mean square velocity as possible effective order parameters in chiral active nematics, distinguishing two chiral nematic states -- active nematic blue phase and chiral active turbulence. This research contributes to the understanding of active turbulence, providing a numerical main phase space parameter sweep to help guide future experimental design and use of active materials.

Tomography of orbital vortex lines in a topological semimetal
T. Figgemeier, M. \"Unzelmann, P. Eck, J. Schusser, L. Crippa, J. N. Neu, B. Geldiyev, P. Kagerer, J. Buck, M. Kall\"ane, M. Hoesch, K. Rossnagel, T. Siegrist, L. -K. Lim, R. Moessner, G. Sangiovanni, D. Di Sante, F. Reinert, H. Bentmann
arXiv:2402.10031v1 Announce Type: new Abstract: Topological defects are inherently stable structures that manifest in a variety of physical settings, from particle physics and cosmology to superfluids and quantum magnets. The geometric structure of Bloch wave functions in a periodic lattice may host topological defects, underpinning the unique properties of topological quantum matter. While pointlike defects, the celebrated Weyl points, have been extensively studied, higher dimensional structures have proven to be harder to pin down. Here, we report the experimental discovery of orbital vortex lines - the first imaging of non-trivial quantum-phase winding at line nodes - in the three-dimensional band structure of a topological semimetal, TaAs. Leveraging dichroic photoemission tomography, we directly image the winding of atomic orbital angular momentum, thereby revealing - and determining the location of - lines of vorticity in full 3D momentum space. We determine the core of the orbital angular momentum vortex to host a so-called almost movable, two-fold spin-degenerate Weyl nodal line, a topological feature predicted to occur in certain non-symmorphic crystals. These results establish the capacity to detect complex topological textures in reciprocal space and may pave the way toward novel orbital transport phenomena in metallic quantum materials.

Gaining insight into molecular tunnel junctions with a pocket calculator without I-V data fitting. Five-thirds protocol
Ioan Baldea
arXiv:2402.10037v1 Announce Type: new Abstract: The proposed protocol is an attempt to meet the experimentalists' legitimate desire of reliably and easily extracting microscopic parameters from current-voltage measurements on molecular junctions. It applies to junctions wherein charge transport dominated by a single level (molecular orbital, MO) occurs via off-resonant tunneling. The recipe is simple. The measured current-voltage curve $I = I(V)$ should be recast as a curve of $V^{5/3}/I$ versus $V$. This curve exhibits two maxima: one at positive bias ($V = V_{p+}$), another at negative bias ($V = V_{p-}$). The values $V_{p +} > 0$ and $V_{p -} < 0$ at the two peaks of the curve for $V^{5/3}/I$ at positive and negative bias and the corresponding values $I_{p +} = I(V_{p+}) > 0$ and $I_{p -} = I(V_{p-}) < 0$ of the current is all information needed as input. The arithmetic average of $V_{p +}$ and $\vert V_{p -}\vert$ in volt provides the value in electronvolt of the MO energy offset $\varepsilon_0 = E_{MO} - E_F$ relative to the electrode Fermi level ($\vert \varepsilon_0\vert = e (V_{p +} + \vert V_{p -}\vert )/2$). The value of the (Stark) strength of the bias-driven MO shift is obtained as $\gamma = (4/5) (V_{p +} - \vert V_{p -} \vert) / (V_{p +} + \vert V_{p -} \vert) $. Even the low-bias conductance estimate, $ G = (3/8) (I_{p +} / V_{p +} + I_{p -} / V_{p -})$, can be a preferable alternative to that deduced from fitting the $I$-$V$ slope in situations of noisy curves at low bias. To demonstrate the reliability and the generality of this ``five-thirds'' protocol, I illustrate its wide applicability for molecular tunnel junctions fabricated using metallic and nonmetallic electrodes, molecular species possessing localized $\sigma$ and delocalized $\pi$ electrons, and} various techniques (mechanically controlled break junctions, STM break junctions, conducting probe AFM junctions, and large area junctions).

Quantum Linear Magnetoresistance and Fermi Liquid Behavior in Kagome Metal Ni3In2S2
P. Das, P. Saha, M. Singh, P. Kumar, S. Patnaik
arXiv:2402.10096v1 Announce Type: new Abstract: Kagome metals gain attention as they manifest a spectrum of quantum phenomena, including superconductivity, charge order, frustrated magnetism, and intertwined correlated states of condensed matter. With regard to electronic band structure, several of the them exhibit non-trivial topological characteristics. Here, we present a thorough investigation on the growth and the physical properties of single crystals of Ni3In2S2 which is established to be a Dirac nodal line Kagome metal. Extensive characterization is attained through temperature and field-dependent resistivity, angle-dependent magnetoresistance and specific heat measurements. In most metals, the Fermi liquid behaviour is mostly restricted to a narrow range of temperature. In Ni3In2S2, this characteristic feature has been observed for an extensive temperature range of 82 K. This is attributed to the strong electron-electron correlation in the material. Specific heat measurements reveal a high Kadowaki-Woods ratio which is in good agreement with strongly correlated systems. Almost linear positive magnetoresistance follows the conventional Kohler scaling which depicts the applicability of semi-classical theories. The angle-dependent magneto-resistance been explained using the Voigt-Thomson formula. Furthermore, de-Haas van Alphen oscillations are observed in magnetization vs. magnetic field measurement which shed light on the topological features in the Shandite Ni3In2S2.

Emergent topological quasiparticle kinetics in constricted nanomagnets
J. Guo, D. Hill, V. Lauter, L. Stingaciu, P. Zolnierczuk, C. A. Ullrich, D. K. Singh
arXiv:2402.10143v1 Announce Type: new Abstract: The ubiquitous domain wall kinetics under magnetic field or current application describes the dynamic properties in nanostructured magnets. However, when the geometrical size of a nanomagnetic system is constricted to the limiting domain wall length scale, the competing energetics between anisotropy, exchange and dipolar interactions can cause emergent kinetics due to quasiparticle relaxation, similar to bulk magnets of atomic origin. Here, we present a joint experimental and theoretical study to support this argument -- constricted nanomagnets, made of antiferromagnetic and paramagnetic neodymium thin film with honeycomb motif, reveal fast kinetic events at ps time scales due to the relaxation of chiral vortex loop-shaped topological quasiparticles that persist to low temperature in the absence of any external stimuli. Such phenomena are typically found in macroscopic magnetic materials. Our discovery is especially important considering the fact that paramagnets or antiferromagnets have no net magnetization. Yet, the kinetics in neodymium nanostructures is quantitatively similar to that found in ferromagnetic counterparts and only varies with the thickness of the specimen. This suggests that a universal, topological quasiparticle mediated dynamical behavior can be prevalent in nanoscopic magnets, irrespective of the nature of underlying magnetic material.

Understanding and tuning magnetism in layered Ising-type antiferromagnet FePSe3 for potential 2D magnet
Rabindra Basnet, Taksh Patel, Jian Wang, Dinesh Upreti, Santosh Karki Chhetri, Gokul Acharya, Md Rafique Un Nabi, Josh Sakon, Jin Hu
arXiv:2402.10155v1 Announce Type: new Abstract: Recent development in two-dimensional (2D) magnetic materials have motivated the search for new van der Waals magnetic materials, especially Ising-type magnets with strong magnetic anisotropy. Fe-based MPX3 (M = transition metal, X = chalcogen) compounds such as FePS3 and FePSe3 both exhibit an Ising-type magnetic order, but FePSe3 receives much less attention compared to FePS3. This work focuses on establishing the strategy to engineer magnetic anisotropy and exchange interactions in this less-explored compound. Through chalcogen and metal substitutions, the magnetic anisotropy is found to be immune against S substitution for Se whereas tunable only with heavy Mn substitution for Fe. In particular, Mn substitution leads to a continuous rotation of magnetic moments from the out-of-plane direction towards in-plane. Furthermore, the magnetic ordering temperature displays non-monotonic doping dependence for both chalcogen and metal substitutions but due to different mechanisms. These findings provide deeper insight into the Ising-type magnetism in this important van der Waals material, shedding light on the study of other Ising-type magnetic systems as well as discovering novel 2D magnets for potential applications in spintronics.

Mirror Chern Bands and Weyl Nodal Loops in Altermagnets
Daniil S. Antonenko, Rafael M. Fernandes, Jorn W. F. Venderbos
arXiv:2402.10201v1 Announce Type: new Abstract: The electronic spectra of altermagnets are a fertile ground for non-trivial topology due to the unique interplay between time-reversal and crystalline symmetries. This is reflected in the unconventional Zeeman splitting between bands of opposite spins, which emerges in the absence of spin-orbit coupling (SOC) and displays nodes along high-symmetry directions. Here, we argue that even for a small SOC, the direction of the magnetic moments in the altermagnetic state has a profound impact on the electronic spectrum, enabling novel topological phenomena to appear. By investigating microscopic models for two-dimensional (2D) and three-dimensional (3D) altermagnets, motivated in part by rutile materials, we demonstrate the emergence of hitherto unexplored Dirac crossings between bands of same spin but opposite sublattices. The direction of the moments determines the fate of these crossings when the SOC is turned on. We focus on the case of out-of-plane moments, which forbid an anomalous Hall effect and thus ensure that no weak magnetization is triggered in the altermagnetic state. In 2D, the SOC gaps out the Dirac crossings, resulting in mirror Chern bands that enable the quantum spin Hall effect and undergo a topological transition to trivial bands upon increasing the magnitude of the magnetic moment. On the other hand, in 3D the crossings persist even in the presence of SOC, forming Weyl nodal loops protected by mirror symmetry. Finally, we discuss possible ways to control these effects in altermagnetic material candidates.

Direction-dependent conductivity in planar Hall set-ups with tilted Weyl/multi-Weyl semimetals
Rahul Ghosh, Ipsita Mandal
arXiv:2402.10203v1 Announce Type: new Abstract: We compute the magnetoelectric conductivity tensors in planar Hall set-ups, which are built with tilted Weyl semimetals (WSMs) and multi-Weyl semimetals (mWSMs), considering distinct relative orientations of the electromagnetic fields ($\mathbf E $ and $\mathbf B $) and the direction of the tilt. The non-Drude part of the response arises from a nonzero Berry curvature in the vicinity of the WSM/mWSM node under consideration. Only in the presence of a nonzero tilt do we find linear-in-$ | \mathbf B| $ terms in set-ups where the tilt-axis is not perpendicular to the plane spanned by $\mathbf E $ and $ \mathbf B $. The advantage of the emergence of the linear-in-$ B$ terms is that, unlike the various $| \mathbf B|^2 $-dependent terms that can contribute to experimental observations, they have purely a topological origin and they dominate the overall response-characteristics in the realistic parameter regimes. The important signatures of these terms are that (1) they change the periodicity of the response from $\pi $ to $2\pi$, when we consider their dependence on the angle $\theta $ between $\mathbf E $ and $\mathbf B $; and (2) lead to an overall change in sign of the conductivity, when measured with respect to the $\mathbf B =0$ case.

Replica topological order in quantum mixed states and quantum error correction
Zhuan Li, Roger S. K. Mong
arXiv:2402.09516v1 Announce Type: cross Abstract: Topological phases of matter offer a promising platform for quantum computation and quantum error correction. Nevertheless, unlike its counterpart in pure states, descriptions of topological order in mixed states remain relatively under-explored. Our work give two definitions for replica topological order in mixed states, which involve $n$ copies of density matrices of the mixed state. Our framework categorizes topological orders in mixed states as either quantum, classical, or trivial, depending on the type of information that can be encoded. For the case of the toric code model in the presence of decoherence, we associate for each phase a quantum channel and describes the structure of the code space. We show that in the quantum-topological phase, there exists a postselection-based error correction protocol that recovers the quantum information, while in the classical-topological phase, the quantum information has decohere and cannot be fully recovered. We accomplish this by describing the mixed state as a projected entangled pairs state (PEPS) and identifying the symmetry-protected topological order of its boundary state to the bulk topology. We discuss the extent that our findings can be extrapolated to $n \to 1$ limit.

Adaptive multi-spectral mimicking with 2D-material nanoresonator networks
Yujie Luo, Thomas Christensen, Ognjen Ilic
arXiv:2402.09681v1 Announce Type: cross Abstract: Active nanophotonic materials that can emulate and adapt between many different spectral profiles -- with high fidelity and over a broad bandwidth -- could have a far-reaching impact, but are challenging to design due to a high-dimensional and complex design space. Here, we show that a metamaterial network of coupled 2D-material nanoresonators in graphene can adaptively match multiple complex absorption spectra via a set of input voltages. To design such networks, we develop a semi-analytical auto-differentiable dipole-coupled model that allows scalable optimization of high-dimensional networks with many elements and voltage signals. As a demonstration of multi-spectral capability, we design a single network capable of mimicking four spectral targets resembling select gases (nitric oxide, nitrogen dioxide, methane, nitrous oxide) with very high fidelity (${>}\,90\%$). Our results are relevant for the design of highly reconfigurable optical materials and platforms for applications in sensing, communication and display technology, and signature and thermal management.

Observation of topology transition in Floquet non-Hermitian skin effects in silicon photonics
Zhiyuan Lin, Wange Song, Li-Wei Wang, Haoran Xin, Jiacheng Sun, Shengjie Wu, Chunyu Huang, Shining Zhu, Jian-Hua Jiang, Tao Li
arXiv:2402.09700v1 Announce Type: cross Abstract: Non-Hermitian physics has greatly enriched our understanding of nonequilibrium phenomena and uncovered novel effects such as the non-Hermitian skin effect (NHSE) that has profoundly revolutionized the field. NHSE is typically predicted in systems with nonreciprocal couplings which, however, are difficult to realize in experiments. Without nonreciprocal couplings, the NHSE can also emerge in systems with coexisting gauge fields and loss or gain (e.g., in Floquet non-Hermitian systems). However, such Floquet NHSE remains largely unexplored in experiments. Here, we realize the Floquet NHSEs in periodically modulated optical waveguides integrated on a silicon photonics platform. By engineering the artificial gauge fields induced by the periodical modulation, we observe various Floquet NHSEs and unveil their rich topological transitions. Remarkably, we discover the transitions between the normal unipolar NHSEs and an unconventional bipolar NHSE which is accompanied by the directional reversal of the NHSEs. The underlying physics is revealed by the band winding in complex quasienergy space which undergoes a topology change from isolated loops with the same winding to linked loops with opposite windings. Our work unfolds a new route toward Floquet NHSEs originating from the interplay between gauge fields and dissipation effects and offers fundamentally new ways for steering light and other waves.

A lattice formulation of Weyl fermions on a single curved surface
Shoto Aoki, Hidenori Fukaya, Naoto Kan
arXiv:2402.09774v1 Announce Type: cross Abstract: In the standard lattice domain-wall fermion formulation, one needs two flat domain-walls where both of the left- and right-handed massless modes appear. In this work we investigate a single domain-wall system with a nontrivial curved background. Specifically we consider a massive fermion on a three-dimensional square lattice, whose domain-wall is a two-dimensional sphere. In the free theory, we find that a single Weyl fermion is localized at the wall and it feels gravity through the induced spin connection. With a topologically nontrivial $U(1)$ link gauge field, however, we find a zero mode with the opposite chirality localized at the center where the gauge field is singular. In the latter case, the low-energy effective theory is not chiral but vectorlike. We discuss how to circumvent this obstacle in formulating lattice chiral gauge theory in the single domain-wall fermion system.

Coevolution of relationship and interaction in cooperative dynamical multiplex networks
Xiaojin Xiong, Ziyan Zeng, Minyu Feng, Attila Szolnoki
arXiv:2402.09804v1 Announce Type: cross Abstract: While actors in a population can interact with anyone else freely, social relations significantly influence our inclination towards particular individuals. The consequence of such interactions, however, may also form the intensity of our relations established earlier. These dynamical processes are captured via a coevolutionary model staged in multiplex networks with two distinct layers. In a so-called relationship layer the weights of edges among players may change in time as a consequence of games played in the alternative interaction layer. As an reasonable assumption, bilateral cooperation confirms while mutual defection weakens these weight factors. Importantly, the fitness of a player, which basically determines the success of a strategy imitation, depends not only on the payoff collected from interactions, but also on the individual relationship index calculated from the mentioned weight factors of related edges. Within the framework of weak prisoner's dilemma situation we explore the potential outcomes of the mentioned coevolutionary process where we assume different topologies for relationship layer. We find that higher average degree of the relationship graph is more beneficial to maintain cooperation in regular graphs, but the randomness of links could be a decisive factor in harsh situations. Surprisingly, a stronger coupling between relationship index and fitness discourage the evolution of cooperation by weakening the direct consequence of a strategy change. To complete our study we also monitor how the distribution of relationship index vary and detect a strong relation between its polarization and the general cooperation level.

Approaching the absorption limit with monolayer semiconductor superlattices
Sara A. Elrafei, Lennart M. Heijnen, Rasmus H. Godiksen, Alberto G. Curto
arXiv:2402.10179v1 Announce Type: cross Abstract: Optical absorption plays a central role in optoelectronic and photonic technologies. Strongly absorbing materials are thus needed for efficient and miniaturized devices. There exists, however, a fundamental limit of 50% absorptance for any ultrathin film in a symmetric environment. Although deviating from these conditions allows higher absorption, finding the thinnest possible material with the highest intrinsic absorption is still desirable. Here, we demonstrate strong absorption approaching the fundamental limit by artificially stacking WS$_2$ monolayers into superlattices. We compare three simple approaches based on different spacer materials to surpass the record peak absorptance of WS2 monolayers, which stands at 16% on ideal substrates. Through direct monolayer stacking without an intentional spacer, we reach a transmittance contrast of 30% for an artificial bilayer, although with limited control over interlayer distance. Using a molecular spacer via spin coating, we demonstrate controllable spacer thickness in a bilayer, reaching 28% transmittance contrast while increasing photoluminescence thanks to doping. Finally, we exploit atomic layer deposition of alumina spacers to boost the transmittance contrast to 36% for a 4-monolayer superlattice. Our results demonstrate that monolayer superlattices are a powerful platform directly applicable to improve exciton-polariton phenomena such as strong light-matter coupling and nanophotonic devices such as modulators and photodetectors.

Guiding light with surface exciton-polaritons in atomically thin superlattices
Sara A. Elrafei, T. V. Raziman, Sandra de Vega, F. Javier Garc\'ia de Abajo, Alberto G. Curto
arXiv:2402.10180v1 Announce Type: cross Abstract: Two-dimensional materials give access to the ultimate physical limits of Photonics with appealing properties for ultracompact optical components such as waveguides and modulators. Specifically, in monolayer semiconductors, a strong excitonic resonance leads to a sharp oscillation in permittivity; at energies close to an exciton, the real part of the permittivity can reach high positive values or even become negative. This extreme optical response enables surface exciton-polaritons to guide visible light bound to an atomically thin layer. However, such ultrathin waveguides support a transverse electric (TE) mode with low confinement and a transverse magnetic (TM) mode with short propagation. Here, we propose that realistic semiconductor-insulator-semiconductor superlattices consisting of monolayer WS$_2$ and hexagonal boron nitride (hBN) can improve the properties of both TE and TM modes. Compared to a single monolayer, a heterostructure with a 1-nm hBN spacer improves the confinement of the TE mode from 1.2 to around 0.5 $\mu$m, whereas the out-of-plane extension of the TM mode increases from 25 to 50 nm. We propose two simple additivity rules for mode confinement valid in the ultrathin film approximation for heterostructures with increasing spacer thickness. Stacking additional WS2 monolayers into superlattices further enhances the waveguiding properties. Our results underscore the potential of monolayer superlattices as a platform for visible nanophotonics with promising optical, electrical, and magnetic tunability

Symmetry breaking at a topological phase transition
Michael F. Faulkner
arXiv:2209.03699v5 Announce Type: replace Abstract: Spontaneous symmetry breaking is a foundational concept in physics. In condensed matter, it characterizes conventional continuous phase transitions but is absent at topological phase transitions such as the Berezinskii-Kosterlitz-Thouless (BKT) transition - as in the BKT case the expected norm (i.e., the magnitude) of the $U(1)$ order parameter vanishes in the thermodynamic limit at all nonzero temperatures. Phenomena consistent with low-temperature broken symmetry have been observed, however, in many different BKT experiments. Examples include recent experiments on superconducting films and the seminal work on two-dimensional arrays of Josephson junctions. While the inaccessibility of the above thermodynamic limit partially explains this paradox in finite systems, the full dynamical framework of symmetry breaking at the BKT transition remains unresolved. Here we provide this by introducing the broader concept of general symmetry breaking. This encompasses both spontaneous symmetry breaking and the BKT case by allowing the expected norm of the order parameter to go to zero in the thermodynamic limit, provided its directional phase fluctuations are asymptotically smaller. We demonstrate this asymptotically slow directional mixing in the low-temperature BKT phase. This explicitly shows that the order parameter arbitrarily chooses some well-defined direction in the thermodynamic limit, predicting negligible phase fluctuations compared to the expected norm in arbitrarily large experimental BKT systems. Our results provide a model for directional mixing timescales across the diverse array of experimental BKT systems. We suggest various experiments.

Probing octupolar hidden order via Janus impurities
Sreekar Voleti, Koushik Pradhan, Subhro Bhattacharjee, Tanusri Saha-Dasgupta, Arun Paramekanti
arXiv:2211.07666v2 Announce Type: replace Abstract: Quantum materials with non-Kramers doublets are a fascinating venue to realize multipolar hidden orders. Impurity probes which break point group symmetries, such as implanted muons or substitutional impurities, split the non-Kramers degeneracy and exhibit a Janus-faced influence in such systems: they can destroy the very order they seek to probe. Here, we explore this duality in cubic osmate double perovskites which are candidates for exotic $d$-orbital octupolar order competing with quadrupolar states. Using {\it ab initio} computations, Landau theory, and Monte Carlo simulations, we show that Janus impurities induce local strain fields, nucleating quadrupolar puddles and suppressing the octupolar $T_c$. At the same time, strains mix the non-Kramers doublet with an excited magnetic triplet, creating parasitic dipole moments which directly expose the hidden octupolar order parameter. Our work unravels this Janus duality in recent impurity nuclear magnetic resonance (NMR) experiments, with important implications for uncovering hidden order in diverse multipolar materials.

Magnetic, transport and topological properties of Co-based shandite thin films
Kazuki Nakazawa, Yasuyuki Kato, Yukitoshi Motome
arXiv:2212.09026v3 Announce Type: replace Abstract: The kagome ferromagnet, Co-based shandite Co3Sn2S2, shows a large anomalous Hall effect (AHE) associated with the Weyl nodes. A thin film with a Co kagome monolayer was predicted to exhibit the quantum AHE, which awaits the experimental realisation. However, it is challenging to precisely predict how the Weyl nodes reside in thin films where the lattice and electronic structures are in general different from the bulk. Here we report comprehensive ab initio results for thin films of Co3Sn2S2 with one, two and three Co layers with Sn or S surface terminations. We find that all the Sn-end films stabilise a ferromagnetic state similar to the bulk, and retain the large AHE down to the monolayer limit where the AHE is quantised, while the magnetic and topological properties drastically change with the number of Co layers in the S-end films. Our results would stimulate further experimental exploration of thin Weyl materials.

Low-temperature magnetoresistance hysteresis in Vanadium-doped Bi$_{2}$Te$_{2.4}$Se$_{0.6}$ bulk topological insulators
Birkan D\"uzel, Christian Riha, Karl Graser, Olivio Chiatti, Saskia F. Fischer
arXiv:2212.14078v2 Announce Type: replace Abstract: Bi$_{2}$Te$_{2.4}$Se$_{0.6}$ single crystals show gapless topological surface states and doping ($x$) with Vanadium allows to shift the chemical potential in the bulk band gap. Accordingly, the resistivity, carrier density, and mobility are constant below 10 K and the magnetoresistance shows weak antilocalization as expected for low-temperature transport properties dominated by gapless surface states of so-called three-dimensional topological "insulators". However, the magnetoresistance also shows a hysteresis depending on the sweep rate and the magnetic field direction. Here, we provide evidence that such magnetoresistance hysteresis is enhanced if both three-dimensional bulk states and quasi-two-dimensional topological states contribute to the transport ($x$ = 0 and 0.03), and it is mostly suppressed if the topological states govern transport ($x$ = 0.015). The results are discussed in terms of spin-dependent scattering between the different available states

Discovery of Atomic Clock-Like Spin Defects in Simple Oxides from First Principles
Joel Davidsson, Mykyta Onizhuk, Christian Vorwerk, Giulia Galli
arXiv:2302.07523v3 Announce Type: replace Abstract: Virtually noiseless due to the scarcity of spinful nuclei in the lattice, simple oxides hold promise as hosts of solid-state spin qubits. However, no suitable spin defect has yet been found in these systems. Using high-throughput first-principles calculations, we predict spin defects in calcium oxide with electronic properties remarkably similar to those of the NV center in diamond. These defects are charged complexes where a dopant atom -- Sb, Bi, or I -- occupies the volume vacated by adjacent cation and anion vacancies. The predicted zero phonon line shows that the Bi complex emits in the telecommunication range, and the computed many-body energy levels suggest a viable optical cycle required for qubit initialization. Notably, the high-spin nucleus of each dopant strongly couples to the electron spin, leading to many controllable quantum levels and the emergence of atomic clock-like transitions that are well protected from environmental noise. Specifically, the Hanh-echo coherence time increases beyond seconds at the clock-like transition in the defect with \ch{^{209}Bi}. Our results pave the way to designing quantum states with long coherence times in simple oxides, making them attractive platforms for quantum technologies.

Quantum Hall Effect in a Weyl-Hubbard Model: Interplay between Topology and Correlation
Snehasish Nandy, Christopher Lane, Jian-Xin Zhu
arXiv:2306.06183v2 Announce Type: replace Abstract: The interplay between topology and electronic correlation effects offers a rich avenue for discovering emergent quantum phenomena in condensed matter systems. In this work, starting from the Weyl-Hubbard model, we investigate the quantum Hall effect to explore the consequence of onsite Hubbard repulsion on nontrivial Weyl band topology in the presence of an external magnetic field. Within the Gutzwiller projected wavefunction method, we find the system to undergo multiple topological phase transitions, including two distinct Weyl phases with a different number of Weyl node pairs and a trivial narrow band insulator, by tuning on-site Coulomb interaction. Interestingly, these two Weyl phases can be identified by the sign of their chiral Landau levels. The possible experimental signature of these topological phases and correlation effects is provided by the magnetic-field dependent quantum Hall conductivity within the Kubo response theory.

Dispersion of Multiferroic Nanoparticles in a Bent-Core Nematic Liquid Crystal: Experimental and Theoretical Study
Dhananjoy Mandal, Yiwei Wang, Supreet Kaur, Golam Mohiuddin, Apala Majumdar, Aloka Sinha
arXiv:2306.14623v2 Announce Type: replace Abstract: A novel nanocomposite system has been prepared by dispersing multiferroic bismuth ferrite nanoparticles (BiFeO$_3$) in a bent-core nematic liquid crystal (8-F-OH) that exhibits cybotactic clusters. Transition temperature, optical textures, order parameter $S_m$, and dielectric spectroscopy experiments are performed in the doped system, and the results are compared with the pure one. The main experimental outcome is that the doped system has increased orientational order parameters, even though the cybotactic cluster size is reduced due to the incorporation of multiferroic BiFeO$_3$ nanoparticles. The transition temperature, as observed under polarising optical microscopy, clearly indicates a reduction of $1 - 2~ ^\circ{\rm C}$ in the doped system compared to the pure one, and we conjecture this is due to the disordering of the cybotactic cluster in the doped system. Based on the experimental findings, a Landau-de Gennes-type free energy model is developed. The model qualitatively explains the increased mean order parameter and the disordering of cybotactic clusters with increasing polarization value of nanoparticles. This is corroborated by experimental findings.

Edge Theories for Anyon Condensation Phase Transitions
David M. Long, Andrew C. Doherty
arXiv:2307.12509v3 Announce Type: replace Abstract: The algebraic tools used to study topological phases of matter are not clearly suited to studying processes in which the bulk energy gap closes, such as phase transitions. We describe an elementary two edge thought experiment which reveals the effect of an anyon condensation phase transition on the robust edge properties of a sample, bypassing a limitation of the algebraic description. In particular, the two edge construction allows some edge degrees of freedom to be tracked through the transition, despite the bulk gap closing. The two edge model demonstrates that bulk anyon condensation induces symmetry breaking in the edge model. Further, the construction recovers the expected result that the number of chiral current carrying modes at the edge cannot change through anyon condensation. We illustrate the construction through detailed analysis of anyon condensation transitions in an achiral phase, the toric code, and in chiral phases, the Kitaev spin liquids.

Topological Quantum Computation on a Chiral Kondo Chain
Tianhao Ren, Elio J. K\"onig, Alexei M. Tsvelik
arXiv:2309.03010v5 Announce Type: replace Abstract: We describe the chiral Kondo chain model based on the symplectic Kondo effect and demonstrate that it has a quantum critical ground state populated by non-Abelian anyons. We show that the fusion channel of two arbitrary anyons can be detected by locally coupling the two anyons to an extra single channel of chiral current and measuring the corresponding conductance at finite frequency. Based on such measurements, we propose that the chiral Kondo chain model with symplectic symmetry can be used for implementation of measurement-only topological quantum computations, and it possesses a number of distinct features favorable for such applications. The sources and effects of errors in the proposed system are analyzed, and possible material realizations are discussed.

Mass of quantum topological excitations and order parameter finite size dependence
Gesualdo Delfino, Marianna Sorba
arXiv:2309.06206v2 Announce Type: replace Abstract: We consider the spontaneously broken regime of the $O(n)$ vector model in $d=n+1$ space-time dimensions, with boundary conditions enforcing the presence of a topological defect line. Comparing theory and finite size dependence of one-point functions observed in recent numerical simulations we argue that the mass of the underlying topological quantum particle becomes infinite when $d\geq 4$.

Disorder and diffuse scattering in single-chirality (TaSe$_4$)$_2$I crystals
Jacob A. Christensen, Simon Bettler, Kejian Qu, Jeffrey Huang, Soyeun Kim, Yinchuan Lu, Chengxi Zhao, Jin Chen, Matthew J. Krogstad, Toby J. Woods, Fahad Mahmood, Pinshane Y. Huang, Peter Abbamonte, Daniel P. Shoemaker
arXiv:2309.10236v4 Announce Type: replace Abstract: The quasi-one-dimensional chiral compound (TaSe$_4$)$_2$I has been extensively studied as a prime example of a topological Weyl semimetal. Upon crossing its phase transition temperature $T_\textrm{CDW}$ $\approx$ 263 K, (TaSe$_4$)$_2$I exhibits incommensurate charge density wave (CDW) modulations described by the well-defined propagation vector $\sim$(0.05, 0.05, 0.11), oblique to the TaSe$_4$ chains. Although optical and transport properties greatly depend on chirality, there is no systematic report about chiral domain size for (TaSe$_4$)$_2$I. In this study, our single-crystal scattering refinements reveal a bulk iodine deficiency, and Flack parameter measurements on multiple crystals demonstrate that separate (TaSe$_4$)$_2$I crystals have uniform handedness, supported by direct imaging and helicity dependent THz emission spectroscopy. Our single-crystal X-ray scattering and calculated diffraction patterns identify multiple diffuse features and create a real-space picture of the temperature-dependent (TaSe$_4$)$_2$I crystal structure. The short-range diffuse features are present at room temperature and decrease in intensity as the CDW modulation develops. These transverse displacements, along with electron pinning from the iodine deficiency, help explain why (TaSe$_4$)$_2$I behaves as an electronic semiconductor at temperatures above and below $T_\textrm{CDW}$, despite a metallic band structure calculated from density functional theory of the ideal structure.

Controlling Umklapp scattering in bilayer graphene moir'e superlattice
Mohit Kumar Jat, Shubhankar Mishra, Harsimran Kaur Mann, Robin Bajaj, Kenji Watanabe, Takashi Taniguchi, H. R. Krishnamurthy, Manish Jain, Aveek Bid
arXiv:2310.08906v2 Announce Type: replace Abstract: In this Letter, we present experimental findings on electron-electron scattering in a two-dimensional moir'e heterostructure with tunable Fermi wave vector, reciprocal lattice vector, and band gap. We achieve this in high-mobility aligned heterostructures of bilayer graphene (BLG) and hBN. Around half-filling, the primary contribution to the resistance of BLG/hBN aligned superlattices arises from electron-electron Umklapp (Uee) scattering, making the resistance of graphene/hBN moir'e devices significantly larger than that of non-aligned devices (where Uee is forbidden). We quantify the strength of the Uee scattering and find that it follows a universal scaling with Fermi energy and has a non-monotonic dependence on the charge carrier density. The Uee scattering is strongly electric field tunable and affected by layer-polarization of BLG. It has a strong particle-hole asymmetry - the resistance when the chemical potential is in the conduction band is significantly lesser than when it is in the valence band, making the electron-doped regime more practical for potential applications.

Intercalation-induced states at the Fermi level and the coupling of intercalated magnetic ions to conducting layers in Ni$_{1/3}$NbS$_2$
Yuki Utsumi Boucher, Izabela Bia{\l}o, Mateusz A. Gala, Wojciech Tabi\'s, Marcin Rosmus, Natalia Olszowska, Jacek J. Kolodziej, Bruno Gudac, Mario Novak, Naveen Kumar Chogondahalli Muniraju, Ivo Batisti\'c, Neven Bari\v{s}i\'c, Petar Pop\v{c}evi\'c, Eduard Tuti\v{s}
arXiv:2401.05884v2 Announce Type: replace Abstract: The magnetic sublayers introduced by intercalation into the host transition-metal dichalcogenide (TMD) are known to produce various magnetic states. The magnetic sublayers and their magnetic ordering strongly modify the electronic coupling between layers of the host compound. Understanding the roots of this variability is a significant challenge. Here we employ the angle-resolved photoelectron spectroscopy at various photon energies, the {\it ab initio} electronic structure calculations, and modeling to address the particular case of Ni-intercalate, Ni$_{1/3}$NbS$_2$. We find that the bands around the Fermi level bear the signature of a strong yet unusual hybridization between NbS$_2$ conduction band states and the Ni 3$d$ orbitals. The hybridization between metallic NbS$_2$ layers is almost entirely suppressed in the central part of the Brillouin zone, including the part of the Fermi surface around the $\mathrm{\Gamma}$ point. Simultaneously, it gets very pronounced towards the zone edges. It is shown that this behavior is the consequence of the rather exceptional, {\it symmetry imposed}, spatially strongly varying, {\it zero total} hybridization between relevant Ni magnetic orbitals and the neighboring Nb orbitals that constitute the metallic bands. We also report the presence of the so-called $\beta$-feature, discovered only recently in two other magnetic intercalates with very different magnetic orderings. In Ni$_{1/3}$NbS$_2$, the feature shows only at particular photon energies, indicating its bulk origin. Common to prior observations, it appears as a series of very shallow electron pockets at the Fermi level, positioned along the edge of the Brillouin zone. Unforeseen by {\it ab initio} electronic calculations, and its origin still unresolved, the feature appears to be a robust consequence of the intercalation of 2H-NbS$_2$ with magnetic ions.

Topological Hall effect induced by chiral fluctuations in a kagome lattice
Kyle Fruhling, Alenna Streeter, Sougata Mardanya, Xiaoping Wang, Priya Baral, Oksana Zaharko, Igor I. Mazin, Sugata Chowdhury, William D. Ratcliff, Fazel Tafti
arXiv:2401.17449v2 Announce Type: replace Abstract: Topological Hall effect (THE) is a hallmark of scalar spin chirality, which is found in static skyrmion lattices. Recent theoretical works have shown that scalar spin chirality could also emerge dynamically from thermal spin fluctuations. Evidence of such a mechanism was found in the kagome magnet YMn6Sn6 where fluctuations arise from frustrated exchange interactions between Mn kagome layers. In YMn6Sn6, the rare-earth ion Y3+ is non-magnetic. When it is replaced by a magnetic ion (Gd3+-Ho3+), the intrinsically antiferromagnetic Mn-Mn interlayer coupling is overwhelmed by the indirect ferromagnetic Mn-R-Mn one, relieving frustration. This generates interesting anomalous Hall conductivity, but not THE. Here we show that Er lies in an intermediate regime where direct and indirect interactions closely compete, so that ErMn6Sn6 can switch from one regime to the other by temperature, i.e., from a collinear ferrimagnetic ground state to a spiral antiferromagnet at 78 K. The AFM phase forms a dome in the temperature-field phase diagram. Close to the boundary of this dome, we find a sizable fluctuations-driven THE, thus underscoring the universality of this mechanism for generating non-zero scalar spin chirality.

Promising regimes for the observation of topological degeneracy in spin chains
Alexander Sattler, Maria Daghofer
arXiv:2402.02813v2 Announce Type: replace Abstract: Both the Haldane spin chain and a topologically dimerized chain feature topologically protected edge states that are expected to be robust against some kind of noise. To elucidate whether it might be feasible to create such edge states in dimerized chains in a controlled manner in solid states environments, e.g. as spin chains on surfaces, as has already been successfully achieved with the Haldane chain, we investigate their robustness with respect to long-range coupling, anisotropies and finite chain length. The theoretical investigation is based on an alternating Heisenberg spin chain with spin-1/2, which is investigated using exact diagonalization. We find that dimerized chains and Haldane chains have robustness against long-range coupling and anisotropies. In particular, dimerized spin chains are significantly more robust than Haldane chains

Theory of biexciton-polaritons in transition metal dichalcogenide monolayers
Andrey Kudlis, Ivan A. Aleksandrov, Mikhail M. Glazov, Ivan A. Shelykh
arXiv:2402.09110v2 Announce Type: replace Abstract: We theoretically investigate a nonlinear optical response of a planar microcavity with an embedded transition metal dicalcogenide monolayer of a when an energy of a biexcitonic transition is brought in resonance with an energy of a cavity mode. We demonstrate that the emission spectrum of this system strongly depends on an external pump. For small and moderate pumps we reveal the presence of a doublet in the emission with the corresponding Rabi splitting scaling as a square root of the number of the excitations in the system. Further increase of the pump leads to the reshaping of the spectrum, which demonstrates the pattern typical for a Mollow triplet. An intermediate pumping regime shows a broad irregular spectrum reminiscent of a chaotic dynamics of the system.

Optimizing the magnon-phonon cooperativity in planar geometries
K. An, C. Kim, K. -W. Moon, R. Kohno, G. Olivetti, G. de Loubens, N. Vukadinovic, J. Ben Youssef, C. Hwang, O. Klein
arXiv:2302.09936v2 Announce Type: replace-cross Abstract: Optimizing the cooperativity between two distinct particles is an important feature of quantum information processing. Of particular interest is the coupling between spin and phonon, which allows for integrated long range communication between gates operating at GHz frequency. Using local light scattering, we show that, in magnetic planar geometries, this attribute can be tuned by adjusting the orientation and strength of an external magnetic field. The coupling strength is enhanced by about a factor of 2 for the out-of-plane magnetized geometry where the Kittel mode is coupled to circularly polarized phonons, compared to the in-plane one where it couples to linearly polarized phonons. We also show that the overlap between magnon and phonon is maximized by matching the Kittel frequency with an acoustic resonance that satisfies the half-wave plate condition across the magnetic film thickness. Taking the frequency dependence of the damping into account, a maximum cooperativity of about 6 is reached in garnets for the normal configuration near 5.5 GHz.

Strongly clustered random graphs via triadic closure: An exactly solvable model
Lorenzo Cirigliano, Claudio Castellano, Gareth Baxter, G\'abor Tim\'ar
arXiv:2311.05312v2 Announce Type: replace-cross Abstract: Triadic closure, the formation of a connection between two nodes in a network sharing a common neighbor, is considered a fundamental mechanism determining the clustered nature of many real-world topologies. In this work we define a static triadic closure (STC) model for clustered networks, whereby starting from an arbitrary fixed backbone network, each triad is closed independently with a given probability. Assuming a locally treelike backbone we derive exact expressions for the expected number of various small, loopy motifs (triangles, 4-loops, diamonds and 4-cliques) as a function of moments of the backbone degree distribution. In this way we determine how transitivity and its suitably defined generalizations for higher-order motifs depend on the heterogeneity of the original network, revealing the existence of transitions due to the interplay between topologically inequivalent triads in the network. Furthermore, under reasonable assumptions for the moments of the backbone network, we establish approximate relationships between motif densities, which we test in a large dataset of real-world networks. We find a good agreement, indicating that STC is a realistic mechanism for the generation of clustered networks, while remaining simple enough to be amenable to analytical treatment.

A lattice regularization of Weyl fermions in a gravitational background
Shoto Aoki, Hidenori Fukaya, Naoto Kan
arXiv:2401.05636v2 Announce Type: replace-cross Abstract: We report on a lattice fermion formulation with a curved domain-wall mass term to nonperturbatively describe fermions in a gravitational background. In our previous work in 2022, we showed under the time-reversal symmetry that the edge-localized massless Dirac fermion appears on one and two-dimensional spherical domain-walls and the spin connection is induced on the lattice in a consistent way with continuum theory. In this work, we extend our study to the Shamir type curved domain-wall fermions without the time-reversal symmetry. We find in the free fermion case that a single Weyl fermion appears on the edge, and feels gravity through the induced spin connection. With a topologically nontrivial $U(1)$ gauge potential, however, we find an oppositely chiral zero mode at the center where the gauge field is singular.

Found 7 papers in prb
Date of feed: Fri, 16 Feb 2024 04:17:05 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)

Pressure-induced structural and electronic phase transitions in GaGeTe
Amit Pawbake, Christophe Bellin, Lorenzo Paulatto, Deepa S. Narang, Keevin Béneut, Benoit Baptiste, Paola Giura, Johan Biscaras, Federico Alabarse, Dattatray J. Late, Otakar Frank, and Abhay Shukla
Author(s): Amit Pawbake, Christophe Bellin, Lorenzo Paulatto, Deepa S. Narang, Keevin Béneut, Benoit Baptiste, Paola Giura, Johan Biscaras, Federico Alabarse, Dattatray J. Late, Otakar Frank, and Abhay Shukla

Chalcogenide-based compounds are an important part of the family of layered materials, extensively studied for their two-dimensional properties. An interesting line of investigation relates to the evolution of their properties with hydrostatic pressure, which could lead to structural transitions and…

[Phys. Rev. B 109, 054107] Published Thu Feb 15, 2024

Flat Landau levels and interface states in two-dimensional photonic crystals with a nodal ring
Meng-Cheng Jin, Ze-Guo Chen, Ming-Hui Lu, Peng Zhan, and Yan-Feng Chen
Author(s): Meng-Cheng Jin, Ze-Guo Chen, Ming-Hui Lu, Peng Zhan, and Yan-Feng Chen

Line degeneracies in the band structures have been largely explored and exhibit exotic phenomena, particularly in three-dimensional (3D) photonic crystals. The flat Landau levels are a generic feature of nodal ring semimetals when a magnetic field perpendicular to the nodal ring plane is applied. Ho…

[Phys. Rev. B 109, 054108] Published Thu Feb 15, 2024

Observation of double-kink states in multivalley acoustic crystals
Xiao-Hui Gou, Hua-Shan Lai, Xiao-Chen Sun, Si-Yuan Yu, Y. B. Chen, Cheng He, and Yan-Feng Chen
Author(s): Xiao-Hui Gou, Hua-Shan Lai, Xiao-Chen Sun, Si-Yuan Yu, Y. B. Chen, Cheng He, and Yan-Feng Chen

Graphene structures usually accommodate one pair of Dirac cones, naturally forming a single kink valley state after symmetry breaking. The authors report here that acoustic S-graphene, i.e., a carbon allotrope of graphene, can harbor two pairs of Dirac cones, further shaping double-kink valley states. By selectively exciting different symmetric or antisymmetric branches, robust yet tunable superdirectional sound radiation is experimentally demonstrated. This study could double the degrees of freedom for valleytronics and help in the design of unique functional devices.

[Phys. Rev. B 109, 054109] Published Thu Feb 15, 2024

Electrostatically coupled tunable topological phononic metamaterials for angular velocity sensing
Jian Zhao, Xianze Zheng, Najib Kacem, Zeyuan Dong, and Pengbo Liu
Author(s): Jian Zhao, Xianze Zheng, Najib Kacem, Zeyuan Dong, and Pengbo Liu

We propose an electrostatically coupled phononic metamaterial for angular velocity sensing, whose sensitivity is immune to external damping and local material defects; furthermore, the coupling strength and frequency range of bands are tunable by the voltages applied to the lattices. The induced Cor…

[Phys. Rev. B 109, 075136] Published Thu Feb 15, 2024

Electric field induced out-of-plane second-order optical nonlinearity in monolayer transition metal dichalcogenides
Zhizi Guan, Yunkun Xu, Junwen Li, Hailong Wang, Zhiwei Peng, Dangyuan Lei, and David J. Srolovitz
Author(s): Zhizi Guan, Yunkun Xu, Junwen Li, Hailong Wang, Zhiwei Peng, Dangyuan Lei, and David J. Srolovitz

Second-order nonlinear optical effects in monolayer transition-metal dichalcogenides (ML TMDCs) have attracted significant attention; these are almost exclusively associated with their in-plane second-order nonlinear susceptibility arising from the intrinsically broken in-plane inversion symmetry. H…

[Phys. Rev. B 109, 075417] Published Thu Feb 15, 2024

Space charge and screening of a supercritical impurity cluster in monolayer graphene
Eugene B. Kolomeisky and Joseph P. Straley
Author(s): Eugene B. Kolomeisky and Joseph P. Straley

A Coulomb impurity of charge $Ze$ is known to destabilize the ground state of undoped graphene with respect to creation of screening space charge when $Z$ exceeds the critical value ${Z}_{c}=1/2α$ set by the material's fine structure constant $α$. Recent experimental advances have made it possible t…

[Phys. Rev. B 109, 075418] Published Thu Feb 15, 2024

Intrinsic in-plane magnetononlinear Hall effect in tilted Weyl semimetals
Longjun Xiang and Jian Wang
Author(s): Longjun Xiang and Jian Wang

Armed with the extended semiclassical theory, we propose a Hall effect at $EB$ order, particularly in Weyl semimetals (WSMs). We dub this effect the in-plane magnetononlinear Hall effect (IMHE) since the Hall current and the driving electric and magnetic fields are confined in the same plane. Simila…

[Phys. Rev. B 109, 075419] Published Thu Feb 15, 2024

Found 4 papers in prl
Date of feed: Fri, 16 Feb 2024 04:17:04 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)

Entanglement Detection with Trace Polynomials
Albert Rico and Felix Huber
Author(s): Albert Rico and Felix Huber

We provide a systematic method for nonlinear entanglement detection based on trace polynomial inequalities. In particular, this allows us to employ multipartite witnesses for the detection of bipartite states, and vice versa. We identify pairs of entangled states and witnesses for which linear detec…

[Phys. Rev. Lett. 132, 070202] Published Thu Feb 15, 2024

Topologically Protected Strong-Interaction of Photonics with Free Electrons
Jing Li (李靖), Yiqi Fang, and Yunquan Liu
Author(s): Jing Li (李靖), Yiqi Fang, and Yunquan Liu

We propose a robust scheme of studying the strong interactions between free electrons and photons using topological photonics. Our study reveals that the topological corner state can be used to enhance the interaction between light and a free electron significantly. The quality factor of the topolog…

[Phys. Rev. Lett. 132, 073801] Published Thu Feb 15, 2024

Metal-Insulator Transition in a Semiconductor Heterobilayer Model
Yubo Yang (杨煜波), Miguel A. Morales, and Shiwei Zhang
Author(s): Yubo Yang (杨煜波), Miguel A. Morales, and Shiwei Zhang

Transition metal dichalcogenide superlattices provide an exciting new platform for exploring and understanding a variety of phases of matter. The moiré continuum Hamiltonian, of two-dimensional jellium in a modulating potential, provides a fundamental model for such systems. Accurate computations wi…

[Phys. Rev. Lett. 132, 076503] Published Thu Feb 15, 2024

Discovery of Magnetic Phase Transitions in Heavy-Fermion Superconductor ${\mathrm{CeRh}}_{2}{\mathrm{As}}_{2}$
Grzegorz Chajewski and Dariusz Kaczorowski
Author(s): Grzegorz Chajewski and Dariusz Kaczorowski

We report on the specific heat studies performed on a new generation of ${\mathrm{CeRh}}_{2}{\mathrm{As}}_{2}$ single crystals. Superior quality of the samples and dedicated experimental protocol allowed us to observe an antiferromagneticlike behavior in the normal state and to detect the first-orde…

[Phys. Rev. Lett. 132, 076504] Published Thu Feb 15, 2024

Found 1 papers in prx
Date of feed: Fri, 16 Feb 2024 04:17:03 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)

Nonlocal Electrodynamics in Ultrapure ${\mathrm{PdCoO}}_{2}$
Graham Baker, Timothy W. Branch, J. S. Bobowski, James Day, Davide Valentinis, Mohamed Oudah, Philippa McGuinness, Seunghyun Khim, Piotr Surówka, Yoshiteru Maeno, Thomas Scaffidi, Roderich Moessner, Jörg Schmalian, Andrew P. Mackenzie, and D. A. Bonn
Author(s): Graham Baker, Timothy W. Branch, J. S. Bobowski, James Day, Davide Valentinis, Mohamed Oudah, Philippa McGuinness, Seunghyun Khim, Piotr Surówka, Yoshiteru Maeno, Thomas Scaffidi, Roderich Moessner, Jörg Schmalian, Andrew P. Mackenzie, and D. A. Bonn

A new method for studying nondiffusive electron flow, based on microwave spectroscopy, reveals clear signs of ballistic flow in the ultrapure material PdCoO2 as well as novel anisotropic electron motion.

[Phys. Rev. X 14, 011018] Published Thu Feb 15, 2024

Found 1 papers in nano-lett
Date of feed: Thu, 15 Feb 2024 14:11:27 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] Fluorescence Enhancement in Topologically Optimized Gallium Phosphide All-Dielectric Nanoantennas
Cynthia Vidal, Benjamin Tilmann, Sunny Tiwari, T. V. Raziman, Stefan A. Maier, Jérôme Wenger, and Riccardo Sapienza

TOC Graphic

Nano Letters
DOI: 10.1021/acs.nanolett.3c03773

Found 2 papers in nat-comm

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)

Non-volatile electrical polarization switching via domain wall release in 3R-MoS2 bilayer
< author missing >

Nonlinear topological symmetry protection in a dissipative system
< author missing >

Found 1 papers in adv-mater
Date of feed: Thu, 15 Feb 2024 08:15:22 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)

Symmetry‐Triggered Tunable Phosphorescence Lifetime of Graphene Quantum Dots in a Solid State
Yongqiang Li, Liangfeng Chen, Siwei Yang, Genwang Wei, Xue Ren, Anli Xu, Hang Wang, Peng He, Hui Dong, Gang Wang, Caichao Ye, Guqiao Ding
Advanced Materials, Accepted Article.