Found 35 papers in cond-mat
Date of feed: Tue, 11 Jul 2023 00:30:00 GMT

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Effects of anisotropy on the high field magnetoresistance of Weyl semimetals. (arXiv:2307.03772v1 [cond-mat.mes-hall])
A. S. Dotdaev, Ya. I. Rodionov, K. I. Kugel, B. A. Aronzon

We study the effects of anisotropy on the magnetoresistance of Weyl semimetals (WSMs) in the ultraquantum regime. We utilize the fact that many Weyl semimetals are approximately axially anisotropic. We find that anisotropy manifests itself in the strong dependence of the magnetoresistance on the polar and azimuthal angles determining the orientation of the anisotropy axis with respect to the applied magnetic field and electric current. We also predict that the ratio of magnetoresistances in the geometries, where the magnetic field and anisotropy axes are aligned and where they are orthogonal, scales as $(v_\bot/v_\parallel)^2$ where $v_\bot$ and $v_\parallel$ are the corresponding Fermi velocities.

The topological Kondo model out of equilibrium. (arXiv:2307.03773v1 [cond-mat.str-el])
Matteo M. Wauters, Chia-Min Chung, Lorenzo Maffi, Michele Burrello

The topological Kondo effect is a genuine manifestation of the nonlocality of Majorana modes. We investigate its out-of-equilibrium signatures in a model with a Cooper-pair box hosting four of these topological modes, each connected to a metallic lead. Through matrix-product-state techniques, we simulate the relaxation of the Majorana magnetization, which allows us to determine the related Kondo temperature. Then, we analyze the onset of electric transport after a quantum quench of a lead voltage. Our results apply to Majorana Cooper-pair boxes fabricated in double nanowire devices and provide non-perturbative evidence of the crossover from weak-coupling states to the strongly correlated topological Kondo regime. The latter dominates at the superconductor charge degeneracy points and displays the expected universal fractional zero-bias conductance.

Chirality probe of twisted bilayer graphene in the linear transport regime. (arXiv:2307.03779v1 [cond-mat.mes-hall])
D. A. Bahamon, G. Gómez-Santos, D. K. Efetov, T. Stauber

We propose a minimal transport experiment in the linear regime that can probe the chirality of twisted moir\'e structures. First, we point out that usual two-terminal conductance measurements cannot access the chirality of a system. Only with a third contact and in the presence of an in-plane magnetic field, a chiral system displays non-reciprocal transport even if all contacts are symmetric. We thus propose to use the third lead as a voltage probe and show that opposite enantiomers give rise to different voltage drops on the third lead. The third lead can also be used as a current probe in the case of layer-discriminating contacts that can detect different handedness even in the absence of a magnetic field. Our exact symmetry considerations are supported by numerical calculations that confirm our conclusions and also demonstrate that there is a change of chirality around the magic angle.

Localization and interaction of interlayer excitons in MoSe$_2$/WSe$_2$ heterobilayers. (arXiv:2307.03842v1 [cond-mat.mes-hall])
Hanlin Fang, Qiaoling Lin, Yi Zhang, Joshua Thompson, Sanshui Xiao, Zhipei Sun, Ermin Malic, Saroj Dash, Witlef Wieczorek

Transition metal dichalcogenide (TMD) heterobilayers provide a versatile platform to explore unique excitonic physics via properties of the constituent TMDs and external stimuli. Interlayer excitons (IXs) can form in TMD heterobilayers as delocalized or localized states. However, the localization of IX in different types of potential traps, the emergence of biexcitons in the high-excitation regime, and the impact of potential traps on biexciton formation have remained elusive. In our work, we observe two types of potential traps in a MoSe$_2$/WSe$_2$ heterobilayer, which result in significantly different emission behavior of IXs at different temperatures. We identify the origin of these traps as localized defect states and the moir{\'e} potential of the TMD heterobilayer. Furthermore, with strong excitation intensity, a superlinear emission behavior indicates the emergence of interlayer biexcitons, whose formation peaks at a specific temperature. Our work elucidates the different excitation and temperature regimes required for the formation of both localized and delocalized IX and biexcitons, and, thus, contributes to a better understanding and application of the rich exciton physics in TMD heterostructures.

Spectroscopic evidence for topological band structure in FeTe$_{0.55}$Se$_{0.45}$. (arXiv:2307.03861v1 [cond-mat.str-el])
Y.-F. Li, S.-D. Chen, M. Garcia-Diez, M. I. Iraola, H. Pfau, Y.-L. Zhu, Z.-Q. Mao, T. Chen, M. Yi, P.-C. Dai, J.A. Sobota, M. Hashimoto, M. G. Vergniory, D.-H. Lu, Z.-X. Shen

FeTe$_{0.55}$Se$_{0.45}$(FTS) occupies a special spot in modern condensed matter physics at the intersections of electron correlation, topology, and unconventional superconductivity. The bulk electronic structure of FTS is predicted to be topologically nontrivial thanks to the band inversion between the $d_{xz}$ and $p_z$ bands along $\Gamma$-$Z$. However, there remain debates in both the authenticity of the Dirac surface states (DSS) and the experimental deviations of band structure from the theoretical band inversion picture. Here we resolve these debates through a comprehensive ARPES investigation. We first observe a persistent DSS independent of $k_z$. Then, by comparing FTS with FeSe which has no band inversion along $\Gamma$-$Z$, we identify the spectral weight fingerprint of both the presence of the $p_z$ band and the inversion between the $d_{xz}$ and $p_z$ bands. Furthermore, we propose a reconciling band structure under the framework of a tight-binding model preserving crystal symmetry. Our results highlight the significant influence of correlation on modifying the band structure and make a strong case for the existence of topological band structure in this unconventional superconductor.

Revealing intrinsic domains and fluctuations of moir\'e magnetism by a wide-field quantum microscope. (arXiv:2307.03876v1 [cond-mat.mes-hall])
Mengqi Huang, Zeliang Sun, Gerald Yan, Hongchao Xie, Nishkarsh Agarwal, Gaihua Ye, Suk Hyun Sung, Hanyi Lu, Jingcheng Zhou, Shaohua Yan, Shangjie Tian, Hechang Lei, Robert Hovden, Rui He, Hailong Wang, Liuyan Zhao, Chunhui Rita Du

Moir\'e magnetism featured by stacking engineered atomic registry and lattice interactions has recently emerged as an appealing quantum state of matter at the forefront condensed matter physics research. Nanoscale imaging of moir\'e magnets is highly desirable and serves as a prerequisite to investigate a broad range of intriguing physics underlying the interplay between topology, electronic correlations, and unconventional nanomagnetism. Here we report spin defect-based wide-field imaging of magnetic domains and spin fluctuations in twisted double trilayer (tDT) chromium triiodide CrI3. We explicitly show that intrinsic moir\'e domains of opposite magnetizations appear over arrays of moir\'e supercells in low-twist-angle tDT CrI3. In contrast, spin fluctuations measured in tDT CrI3 manifest little spatial variations on the same mesoscopic length scale due to the dominant driving force of intralayer exchange interaction. Our results enrich the current understanding of exotic magnetic phases sustained by moir\'e magnetism and highlight the opportunities provided by quantum spin sensors in probing microscopic spin related phenomena on two-dimensional flatland.

Enhanced Strong Coupling between Spin Ensemble and non-Hermitian Topological Edge States. (arXiv:2307.03944v1 [quant-ph])
Jie Qian, Jie Li, Shi-Yao Zhu, J. Q. You, Yi-Pu Wang

Light-matter interaction is crucial to both understanding fundamental phenomena and developing versatile applications. Strong coupling, robustness, and controllability are the three most important aspects in realizing light-matter interactions. Topological and non-Hermitian photonics, have provided frameworks for robustness and extensive control freedom, respectively. How to engineer the properties of the edge state such as photonic density of state, scattering parameters by using non-Hermitian engineering while ensuring topological protection has not been fully studied. Here we construct a parity-time-symmetric dimerized photonic lattice and generate complex-valued edge states via spontaneous PT-symmetry breaking. The enhanced strong coupling between the topological photonic edge mode and magnon mode in a ferromagnetic spin ensemble is demonstrated. Our research reveals the subtle non-Hermitian topological edge states and provides strategies for realizing and engineering topological light-matter interactions.

Transport properties in gapped graphene through magnetic barrier in a laser field. (arXiv:2307.03999v1 [cond-mat.mes-hall])
Rachid El Aitouni, Miloud Mekkaoui, Ahmed Jellal, Michael Schreiber

We study the transport properties of Dirac fermions through gapped graphene through a magnetic barrier irradiated by a laser field oscillating in time. We use Floquet theory and the solution of Weber's differential equation to determine the energy spectrum corresponding to the three regions composing the system. The boundary conditions and the transfer matrix approach {are} employed to explicitly determine the transmission probabilities for multi-energy bands and the associated conductance. As an illustration, we focus only on the three first bands: the central band $T_0$ (zero photon exchange) and the two first side bands $T_{\pm1}$ (photon emission or absorption). It is found that the laser field activates the process of translation through photon exchange. Furthermore, we show that varying the incident angle and energy gap strongly affects the transmission process. The conductance increases when the number of electrons that cross the barrier increases, namely when there is a significant transmission.

Correlation-induced symmetry-broken states in large-angle twisted bilayer graphene on MoS2. (arXiv:2307.04170v1 [cond-mat.mes-hall])
Kaihui Li, Long-Jing Yin, Chenglong Che, Xueying Liu, Yulong Xiao, Songlong Liu, Qingjun Tong, Si-Yu Li, Anlian Pan

Strongly correlated states are commonly emerged in twisted bilayer graphene (TBG) with magic-angle, where the electron-electron (e-e) interaction U becomes prominent relative to the small bandwidth W of the nearly flat band. However, the stringent requirement of this magic angle makes the sample preparation and the further application facing great challenges. Here, using scanning tunneling microscopy (STM) and spectroscopy (STS), we demonstrate that the correlation-induced symmetry-broken states can also be achieved in a 3.45{\deg} TBG, via engineering this non-magic-angle TBG into regimes of U/W > 1. We enhance the e-e interaction through controlling the microscopic dielectric environment by using a MoS2 substrate. Simultaneously, the bandwidth of the low-energy van Hove singularity (VHS) peak is reduced by enhancing the interlayer coupling via STM tip modulation. When partially filled, the VHS peak exhibits a giant splitting into two states flanked the Fermi level and shows a symmetry-broken LDOS distribution with a stripy charge order, which confirms the existence of strong correlation effect in our 3.45{\deg} TBG. Our result paves the way for the study and application of the correlation physics in TBGs with a wider range of twist angle.

Optical Properties of Charged Defects in Monolayer MoS$_2$. (arXiv:2307.04268v1 [cond-mat.mtrl-sci])
Martik Aghajanian, Arash A. Mostofi, Johannes Lischner

We present theoretical calculations of the optical spectrum of monolayer MoS$_2$ with a charged defect. In particular, we solve the Bethe-Salpeter equation based on an atomistic tight-binding model of the MoS$_2$ electronic structure which allows calculations for large supercells. The defect is modelled as a point charge whose potential is screened by the MoS$_2$ electrons. We find that the defect gives rise to new peaks in the optical spectrum approximately 100-200 meV below the first free exciton peak. These peaks arise from transitions involving in-gap bound states induced by the charged defect. Our findings are in good agreement with experimental measurements.

Phononic transport in 1T prime-MoTe2: anisotropic structure with an isotropic lattice thermal conductivity. (arXiv:2307.04278v1 [cond-mat.mtrl-sci])
Xiangyue Cui, Xuefei Yan, Bowen Wang, Yongqing Cai

Molybdenum ditelluride (MoTe2) is an unique transition metal dichalcogenide owing to its energetically comparable 1H and 1T prime phases. This implies a high chance of coexistence of 1H-1T prime heterostructures which poses great complexity in the measurement of the intrinsic lattice thermal conductivities (kappa). In this work, via first-principles calculations, we examine the lattice-wave propagation and thermal conduction in this highly structurally anisotropic 1T prime MoTe2. Our calculation shows that the 1T prime phase has a sound velocity of 2.13 km/s (longitudinal acoustic wave), much lower than that of the 1H phase (4.05 km /s), indicating a staggered transmission of lattice waves across the boundary from 1H to 1T prime phase. Interestingly, the highly anisotropic 1T prime MoTe2 shows nearly isotropic and limited kappa_L of 13.02 W/mK, owing to a large Gruneisen parameter of acoustic flexural mode, heavy masses of Mo and Te elements and a low phonon group velocity. Accumulative kappa_L as a function of mean free path (MFP) indicates phonons with MFP less than ~300 nm contribute 80% of kappa_L and an inflection point at ~600 nm. Our results will be critical for understanding of the size dependent kappa_L of nanostructured 1T prime MoTe2.

Weyl semimetallic state in the Rashba-Hubbard model. (arXiv:2307.04307v1 [cond-mat.str-el])
Katsunori Kubo

We investigate the Hubbard model with the Rashba spin-orbit coupling on a square lattice. The Rashba spin-orbit coupling generates two-dimensional Weyl points in the band dispersion. In a system with edges along [11] direction, zero-energy edge states appear, while no edge state exists for a system with edges along an axis direction. The zero-energy edge states with a certain momentum along the edges are predominantly in the up-spin state on the right edge, while they are predominantly in the down-spin state on the left edge. Thus, the zero-energy edge states are helical. By using a variational Monte Carlo method for finite Coulomb interaction cases, we find that the Weyl points can move toward the Fermi level by the correlation effects. We also investigate the magnetism of the model by the Hartree-Fock approximation and discuss weak magnetic order in the weak-coupling region.

Quasicrystalline second-order topological semimetals. (arXiv:2307.04334v1 [cond-mat.mes-hall])
Rui Chen, Bin Zhou, Dong-Hui Xu

Three-dimensional higher-order topological semimetals in crystalline systems exhibit higher-order Fermi arcs on one-dimensional hinges, challenging the conventional bulk-boundary correspondence. However, the existence of higher-order Fermi arc states in aperiodic quasicrystalline systems remains uncertain. In this work, we present the emergence of three-dimensional quasicrystalline second-order topological semimetal phases by vertically stacking two-dimensional quasicrystalline second-order topological insulators. These quasicrystalline topological semimetal phases are protected by rotational symmetries forbidden in crystals, and are characterized by topological hinge Fermi arcs connecting fourfold degenerate Dirac-like points in the spectrum. Our findings reveal an intriguing class of higher-order topological phases in quasicrystalline systems, shedding light on their unique properties.

Phase Diagram and Crossover Phases of Topologically Ordered Graphene Zigzag Nanoribbons: Role of Localization Effects. (arXiv:2307.04352v1 [cond-mat.str-el])
Hoang Anh Le, In Hwan Lee, Young Heon Kim, S.-R. Eric Yang

We computed the phase diagram of the zigzag graphene nanoribbons as a function of on-site repulsion, doping, and disorder strength. The topologically ordered phase undergoes topological phase transitions into crossover phases, which are new disordered phases with a nonuniversal topological entanglement entropy with significant variance. The topological order is destroyed by competition between localization effects and on-site repulsion. We found that strong on-site repulsion and/or doping weakens the nonlocal correlations between the opposite zigzag edges. In one of the crossover phases, both $\frac{e^-}{2}$ fractional charges and spin-charge separation were absent; however, charge-transfer correlations between the zigzag edges were possible. Another crossover phase contains $\frac{e^-}{2}$ fractional charges, but no charge transfer correlations. In low-doped zigzag ribbons the interplay between electron localization and on-site repulsion contributes to the spatial separation of quasi-degenerate gap-edge states and protects the charge fractionalization against quantum fluctuations. In all these effects, mixed chiral gap-edge states play an important role. The properties of nontopological strongly disordered and strongly repulsive phases are also observed. Each phase of the phase diagram has a different zigzag-edge structure.

Novel Carbon allotropes with mixed hybridizations: ene-C10, and ene-yne-C14. Crystal chemistry and first principles investigations. (arXiv:2307.04359v1 [cond-mat.mtrl-sci])
Samir F. Matar

Based on C8, carbon 4C, with cfc topology, two hybrid carbon allotropes generated by inserting C(sp2) and C(sp1) carbon atoms into C8 diamond-like lattice were identified and labeled ene-C10 containing C(sp2) and ene-yne-C14 containing C(sp2 and sp1). The introduced double and triple chemical descriptions were illustrated from the projected charge densities. The crystal density and the cohesive energy were found to decrease due to the enhanced openness of the structures from inserted sp2/sp1 carbons, with a resulting decrease of the hardness along the series C8, C10, C12, and C14. The novel hybrid allotropes were found stable mechanically (elastic constants and their combinations) and dynamically (phonons band structures). The thermal properties from the temperature dependence of the heat capacity CV were found to increasingly depart from diamond-like C8 to higher values. From the electronic band structures, the inserted carbons were found to add up bands rigidly to diamond-like C8 while being characterized by metallic-like behavior for ene-C10 and ene-yne-C14.

Nonlinear and nonreciprocal transport effects in untwinned thin films of ferromagnetic Weyl metal SrRuO$_3$. (arXiv:2307.04482v1 [cond-mat.mes-hall])
Uddipta Kar (1 and 6), Elisha Cho-Hao Lu (1), Akhilesh Kr. Singh (1) P. V. Sreenivasa Reddy (2), Youngjoon Han (4), Xinwei Li (4), Cheng-Tung Cheng (1), Song Yang (5), Chun-Yen Lin (5), I-Chun Cheng (8), Chia-Hung Hsu (5), D. Hsieh (4), Wei-Cheng Lee (3), Guang-Yu Guo (2 and 7), Wei-Li Lee (1) ((1) Institute of Physics, Academia Sinica, Nankang, Taipei, Taiwan, (2) Department of Physics, National Taiwan University, Taipei, Taiwan, (3) Department of Physics, Applied Physics and Astronomy, Binghamton University, Binghamton, New York, USA, (4) Department of Physics, California Institute of Technology, Pasadena, California, USA, (5) Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan, (6) Nano Science and Technology, Taiwan International Graduate Program, Academia Sinica and National Taiwan University, Taipei, Taiwan, (7) Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan, (8) Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan)

The identification of distinct charge transport features, deriving from nontrivial bulk band and surface states, has been a challenging subject in the field of topological systems. In topological Dirac and Weyl semimetals, nontrivial conical bands with Fermi-arc surfaces states give rise to negative longitudinal magnetoresistance due to chiral anomaly effect and unusual thickness dependent quantum oscillation from Weyl-orbit effect, which were demonstrated recently in experiments. In this work, we report the experimental observations of large nonlinear and nonreciprocal transport effects for both longitudinal and transverse channels in an untwinned Weyl metal of SrRuO$_3$ thin film grown on a SrTiO$_{3}$ substrate. From rigorous measurements with bias current applied along various directions with respect to the crystalline principal axes, the magnitude of nonlinear Hall signals from the transverse channel exhibits a simple sin$\alpha$ dependent at low temperatures, where $\alpha$ is the angle between bias current direction and orthorhombic [001]$_{\rm o}$, reaching a maximum when current is along orthorhombic [1-10]$_{\rm o}$. On the contrary, the magnitude of nonlinear and nonreciprocal signals in the longitudinal channel attains a maximum for bias current along [001]$_{\rm o}$, and it vanishes for bias current along [1-10]$_{\rm o}$. The observed $\alpha$-dependent nonlinear and nonreciprocal signals in longitudinal and transverse channels reveal a magnetic Weyl phase with an effective Berry curvature dipole along [1-10]$_{\rm o}$ from surface states, accompanied by 1D chiral edge modes along [001]$_{\rm o}$.

Strong transient magnetic fields induced by THz-driven plasmons in graphene disks. (arXiv:2307.04512v1 [cond-mat.mes-hall])
Jeong Woo Han, Pavlo Sai, Dmytro But, Ece Uykur, Stephan Winnerl, Gagan Kumar, Matthew L. Chin, Rachael L. Myers-Ward, Matthew T. Dejarld, Kevin M. Daniels, Thomas E. Murphy, Wojciech Knap, Martin Mittendorff

Strong circularly polarized excitation opens up the possibility to generate and control effective magnetic fields in solid state systems, e.g., via the optical inverse Faraday effect or the phonon inverse Faraday effect. While these effects rely on material properties that can be tailored only to a limited degree, plasmonic resonances can be fully controlled by choosing proper dimensions and carrier concentrations. Plasmon resonances provide new degrees of freedom that can be used to tune or enhance the light-induced magnetic field in engineered metamaterials. Here we employ graphene disks to demonstrate light-induced transient magnetic fields from a plasmonic circular current with extremely high efficiency. The effective magnetic field at the plasmon resonance frequency of the graphene disks (3.5 THz) is evidenced by a strong (~1{\deg}) ultrafast Faraday rotation (~ 20 ps). In accordance with reference measurements and simulations, we estimated the strength of the induced magnetic field to be on the order of 0.7 T under a moderate pump fluence of about 440 nJ cm-2.

Topological engineered 3D printing of Architecturally Interlocked Petal-Schwarzites. (arXiv:2307.04540v1 [cond-mat.mtrl-sci])
Rushikesh S. Ambekar, Leonardo V. Bastos, Douglas S. Galvao, Chandra S. Tiwary, Cristiano F. Woellner

The topologically engineered complex Schwarzites architecture has been used to build novel and unique structural components with a high specific strength. The mechanical properties of these building blocks can be further tuned, reinforcing with stronger and high surface area architecture. In the current work, we have built six different Schwarzites structures with multiple interlocked layers, which we named architecturally interlocked petal-schwarzites (AIPS). These complex structures are 3D printed into macroscopic dimensions and compressed using uniaxial compression. The experimental results show a strong dependency of mechanical response on the number of layers and topology of the layers. Fully atomistic molecular dynamics compressive simulations were also carried out, and the results are in good agreement with experimental observations. They can explain the underlying AIPS mechanism of high specific strength and energy absorption. The proposed approach opens a new perspective on developing new 3D-printed materials with tunable and enhanced mechanical properties.

Global synchronization on time-varying higher-order structures. (arXiv:2307.04568v1 [cond-mat.stat-mech])
Md Sayeed Anwar, Dibakar Ghosh, Timoteo Carletti

Synchronization has received a lot of attention from the scientific community for systems evolving on static networks or higher-order structures, such as hypergraphs and simplicial complexes. In many relevant real world applications, the latter are not static but do evolve in time, in this paper we thus discuss the impact of the time-varying nature of high-order structures in the emergence of global synchronization.

To achieve this goal we extend the master stability formalism to account, in a general way, for the additional contributions arising from the time evolution of the higher-order structure supporting the dynamical systems. The theory is successfully challenged against two illustrative examples, the Stuart-Landau nonlinear oscillator and the Lorenz chaotic oscillator.

Porous CrO$_2$: a ferromagnetic half-metallic member in sparse hollandite oxide family. (arXiv:2307.04584v1 [cond-mat.mtrl-sci])
Sujoy Datta

A stable polymorph of CrO$_2$ is predicted using PBE+U method. The porous material is isostructural with $\alpha$-MnO$_2$ making it the second transition metal oxide in sparse hollandite group of materials. However, unlike the anti-ferromagnetic semiconducting character of the $\alpha$-MnO$_2$, it is found to be a ferromagnetic half-metal. At Fermi level, the hole pocket has ample contribution from O-2$p$ orbital, though, the electron pocket is mostly contributed by Cr-3$d_{xy}$ and Cr-3d$_{x^2-y^2}$. A combination of negative charge transfer through orbital mixing and extended anti-bonding state near Fermi level is responsible for the half-metallic ferromagnetic character of the structure. A comparative study of rutile and hollandite CrO$_2$ and hollandite MnO$_2$ structures delineate the interplay between structural, electronic and magnetic properties. The material shows a robust magnetic character under hydrothermal pressure, as well as, the band topology is conserved under uniaxial strain. Moderate magneto-crystalline anisotropy is observed and it shows a correspondence with the anisotropy of elastic constants.

Endotaxial Stabilization of 2D Charge Density Waves with Long-range Order. (arXiv:2307.04587v1 [cond-mat.mtrl-sci])
Suk Hyun Sung, Nishkarsh Agarwal, Ismail El Baggari, Yin Min Goh, Patrick Kezer, Noah Schnitzer, Yu Liu, Wenjian Lu, Yuping Sun, Lena F. Kourkoutis, John T. Heron, Kai Sun, Robert Hovden

Charge density waves are emergent quantum states that spontaneously reduce crystal symmetry, drive metal-insulator transitions, and precede superconductivity. In low-dimensions, distinct quantum states arise, however, thermal fluctuations and external disorder destroy long-range order. Here we stabilize ordered two-dimensional (2D) charge density waves through endotaxial synthesis of confined monolayers of 1T-TaS$_2$. Specifically, an ordered incommensurate charge density wave (oIC-CDW) is realized in 2D with dramatically enhanced amplitude and resistivity. By enhancing CDW order, the hexatic nature of charge density waves becomes observable. Upon heating via in-situ TEM, the CDW continuously melts in a reversible hexatic process wherein topological defects form in the charge density wave. From these results, new regimes of the CDW phase diagram for 1T-TaS$_2$ are derived and consistent with the predicted emergence of vestigial quantum order.

Moire-enabled artificial topological superconductivity in twisted bilayer graphene. (arXiv:2307.04605v1 [cond-mat.mes-hall])
Maryam Khosravian, Elena Bascones, Jose L. Lado

Twisted van der Waals materials have risen as highly tunable platform for realizing unconventional superconductivity. Here we demonstrate how a topological superconducting state can be driven in a twisted graphene multilayer at a twist angle of approximately 1.6 degrees proximitized to other 2D materials. We show that an encapsulated twisted bilayer subject to induced Rashba spin-orbit coupling, s-wave superconductivity and exchange field generates a topological superconducting state enabled by the moire pattern. We demonstrate a variety of topological states with different Chern numbers highly tunable through doping, strain and bias voltage. Our proposal does not depend on a fine tuning of the twist angle, but solely on the emergence of moire minibands and is applicable for twist angles between 1.3 and 3 degrees. Our results establish the potential of twisted graphene bilayers to create artificial topological superconductivity without requiring ultraflat dispersions.

Surface magnon spectra of nodal loop semimetals. (arXiv:2307.04620v1 [cond-mat.mes-hall])
Assem Alassaf, János Koltai, László Oroszlány

In this paper we establish a connection between the bulk topological structure and the magnetic properties of drumhead surface states of nodal loop semimetals. We identify the magnetic characteristics of the surface states and compute the system's magnon spectrum by treating electron-electron interactions on a mean-field level. We draw attention to a subtle connection between a Lifshitz-like transition of the surface states driven by mechanical distortions and the magnetic characteristics of the system. Our findings may be experimentally verified e.g. by spin polarized electron energy loss spectroscopy of nodal semimetal surfaces.

Reversal of the skyrmion topological deflection across ferrimagnetic angular momentum compensation. (arXiv:2307.04669v1 [cond-mat.mtrl-sci])
L. Berges, R. Weil, A. Mougin, J. Sampaio

Due to their non-trivial topology, skyrmions describe deflected trajectories, which hinders their straight propagation in nanotracks and can lead to their annihilation at the track edges. This deflection is caused by a gyrotropic force proportional to the topological charge and the angular momentum density of the host film. In this article we present clear evidence of the reversal of the topological deflection angle of skyrmions with the sign of angular momentum density. We measured the skyrmion trajectories across the angular momentum compensation temperature (TAC) in GdCo thin films, a rare earth/transition metal ferrimagnetic alloy. The sample composition was used to engineer the skyrmion stability below and above the TAC. A refined comparison of their dynamical properties evidenced a reversal of the skyrmions deflection angle with the total angular momentum density. This reversal is a clear demonstration of the possibility of tuning the skyrmion deflection angle in ferrimagnetic materials and paves the way for deflection-free skyrmion devices.

Non-equilibrium attractor for non-linear stochastic dynamics. (arXiv:2307.04728v1 [cond-mat.stat-mech])
A. Patrón, B. Sánchez-Rey, E. Trizac, A. Prados

We study the dynamical behaviour of mesoscopic systems in contact with a thermal bath, described either via the non-linear Fokker-Planck equation for the probability distribution function at the ensemble level -- or the corresponding non-linear Langevin equation at the trajectory level. Our focus is put on one-dimensional -- or $d$-dimensional isotropic -- systems in confining potentials, with detailed balance -- fluctuation-dissipation thus holds, and the stationary probability distribution has the canonical form at the bath temperature. When quenching the bath temperature to low enough values, a far-from-equilibrium state emerges that rules the dynamics over a characteristic intermediate timescale. Such a long-lived state has a Dirac-delta probability distribution function and attracts all solutions over this intermediate timescale, in which the initial conditions are immaterial while the influence of the bath is still negligible. Numerical evidence and qualitative physical arguments suggest that the above picture extends to higher-dimensional systems, with anisotropy and interactions.

Quantum oscillations with topological phases in a kagome metal CsTi$_3$Bi$_5$. (arXiv:2307.04750v1 [cond-mat.str-el])
Yongkang Li, Hengxin Tan, Binghai Yan

Quantum oscillations can reveal Fermi surfaces and their topology in solids and provide a powerful tool for understanding transport and electronic properties. It is well established that the oscillation frequency maps the Fermi surface area by Onsager's relation. However, the topological phase accumulated along the quantum orbit remains difficult to estimate in calculations, because it includes multiple contributions from the Berry phase, orbital and spin moments, and also becomes gauge-sensitive for degenerate states. In this work, we develop a gauge-independent Wilson loop scheme to evaluate all topological phase contributions and apply it to CsTi$_3$Bi$_5$, an emerging kagome metal. We find that the spin-orbit coupling dramatically alters the topological phase compared to the spinless case. Especially, oscillation phases of representative quantum orbits demonstrate a strong 3D signature despite their cylinder-like Fermi surface geometry. Our work reveals the Fermi surface topology of CsTi$_3$Bi$_5$ and paves the way for the theoretical investigation of quantum oscillations in realistic materials.

Switching on surface conduction in a topological insulator. (arXiv:2010.10620v2 [cond-mat.mtrl-sci] UPDATED)
M. Taupin, G. Eguchi, M. Luznik, A. Steiger-Thirsfeld, Y. Ishida, K. Kuroda, S. Shin, A. Kimura, S. Paschen

The protected surface conduction of topological insulators is in high demand for the next generation of electronic devices. What is needed to move forward are robust settings where topological surface currents can be controlled by simple means, ideally by the application of external stimuli. Surprisingly, this direction is only little explored. In this work we demonstrate that we can boost the surface conduction of a topological insulator by both light and electric field. This happens in a fully controlled way, and the additional Dirac carriers exhibit ultra-long lifetimes. We provide a comprehensive understanding, namely that carriers are injected from the bulk to the surface states across an intrinsic Schottky barrier. We expect this mechanism to be at play in a broad range of materials and experimental settings.

Probing Chern number by opacity and topological phase transition by a nonlocal Chern marker. (arXiv:2207.00016v4 [cond-mat.str-el] UPDATED)
Paolo Molignini, Bastien Lapierre, R. Chitra, Wei Chen

In 2D semiconductors and insulators, the Chern number of the valence band Bloch state is an important quantity that has been linked to various material properties, such as the topological order. We elaborate that the opacity of 2D materials to circularly polarized light over a wide range of frequencies, measured in units of the fine structure constant, can be used to extract a spectral function that frequency-integrates to the Chern number, offering a simple optical experiment to measure it. This method is subsequently generalized to finite temperature and locally on every lattice site by a linear response theory, which helps to extract the Chern marker that maps the Chern number to lattice sites. The long range response in our theory corresponds to a Chern correlator that acts like the internal fluctuation of the Chern marker, and is found to be enhanced in the topologically nontrivial phase. Finally, from the Fourier transform of the valence band Berry curvature, a nonlocal Chern marker is further introduced, whose decay length diverges at topological phase transitions and therefore serves as a faithful indicator of the transitions, and moreover can be interpreted as a Wannier state correlation function. The concepts discussed in this work explore multi-faceted aspects of topology and should help address the impact of system inhomogeneities.

Correlated Fractional Dirac Materials. (arXiv:2207.09449v3 [cond-mat.str-el] UPDATED)
Bitan Roy, Vladimir Juricic

Fractional Dirac materials (FDMs) feature a fractional energy-momentum relation $E(\vec{k}) \sim |\vec{k}|^{\alpha}$, where $\alpha \; (<1)$ is a real noninteger number, in contrast to that in conventional Dirac materials with $\alpha=1$. Here we analyze the effects of short- and long-range Coulomb repulsions in two- and three-dimensional FDMs. Only a strong short-range interaction causes nucleation of a correlated insulator that takes place through a quantum critical point. The universality class of the associated quantum phase transition is determined by the correlation length exponent $\nu^{-1}=d-\alpha$ and dynamic scaling exponent $z=\alpha$, set by the band curvature. On the other hand, the fractional dispersion is protected against long-range interaction due to its nonanalytic structure. Rather, a linear Dirac dispersion gets generated under coarse graining, and the associated Fermi velocity increases logarithmically in the infrared regime, thereby yielding a two-fluid system. Altogether, correlated FDMs unfold a rich landscape accommodating unconventional emergent many-body phenomena.

Theoretical proposal to obtain strong Majorana evidence from scanning tunneling spectroscopy of a vortex with a dissipative environment. (arXiv:2209.14006v3 [cond-mat.supr-con] UPDATED)
Gu Zhang, Chuang Li, Geng Li, Can-Li Song, Xin Liu, Fu-Chun Zhang, Dong E. Liu

It is predicted that a vortex in a topological superconductor contains a Majorana zero mode (MZM). The confirmative Majorana signature, i.e., the $2e^2/h$ quantized conductance, however is easily sabotaged by unavoidable interruptions, e.g. instrument broadening, non-Majorana signal, and extra particle channels. We propose to avoid the signal interruption by introducing disorder-induced dissipation that couples to the tip-sample tunneling. With dissipation involved, we highlight three features, each of which alone can provide a strong evidence to identify MZM. Firstly, dissipation suppresses a finite-energy Caroli-de Gennes-Matricon (CdGM) conductance peak into a valley, while it does not split MZM zero-bias conductance peak. Secondly, we predict a dissipation-dependent scaling feature of the zero-bias conductance peak. Thirdly, the introduced dissipation manifests the MZM signal by suppressing non-topological CdGM modes. Importantly, the observation of these features does not require a quantized conductance value $2e^2/h$.

Thermodynamic efficiency of atmospheric motion governed by Lorenz system. (arXiv:2302.03887v2 [nlin.CD] UPDATED)
Zhen Li, Yuki Izumida

The Lorenz system was derived on the basis of a model of convective atmospheric motion and may serve as a paradigmatic model for considering a complex climate system. In this study, we formulated the thermodynamic efficiency of convective atmospheric motion governed by the Lorenz system by treating it a non-equilibrium thermodynamic system. Based on the fluid conservation equations under the Oberbeck-Boussinesq approximation, the work necessary to maintain atmospheric motion and heat fluxes at the boundaries were calculated. Using these calculations, the thermodynamic efficiency was formulated for stationary and chaotic dynamics. The numerical results show that, for both stationary and chaotic dynamics, the efficiency tends to increase as the atmospheric motion is driven out of thermodynamic equilibrium when the Rayleigh number increases. However, it is shown that the efficiency is upper bounded by the maximum efficiency, which is expressed in terms of the parameters characterizing the fluid and the convective system. The analysis of the entropy generation rate was also performed for elucidating the difference between the thermodynamic efficiency of conventional heat engines and the present atmospheric heat engine. It is also found that there exists an abrupt drop in efficiency at the critical Hopf bifurcation point, where the dynamics change from stationary to chaotic. These properties are similar to those found previously in Malkus-Lorenz waterwheel system.

Ferroelectric metals in 1T/1T'-phase transition metal dichalcogenides bilayers. (arXiv:2303.14343v2 [cond-mat.mtrl-sci] UPDATED)
Haohao Sheng, Zhijun Wang

Ferroelectricity and metallicity cannot coexist due to the screening effect of conducting electrons, and a large number of stable monolayers with 1T/1T$^{\prime}$ phase lack spontaneous polarization due to inversion symmetry (IS). In this work, we have constructed the $\pi$-bilayer structures for transition metal dichalcogenides (TMD; $M$Te$_2,M =$ Pt, Pd, and Ni) with van der Waals stacking, where two monolayers are related by $C_{2z}$ rotation, and have demonstrated that these $\pi$-bilayers are typical ferroelectric metals (FEMs). The $\pi$-bilayer structure widely exist in nature, such as 1T$^{\prime}$/T$_d$-TMD, $\alpha$-Bi$_4$Br$_4$. The computed vertical polarization of PtTe$_2$ and MoTe$_2$ $\pi$-bilayers are 0.46 and 0.25 pC/m, respectively. We show that the switching of polarization can be realized through interlayer sliding, which only requires crossing a low energy barrier. The interlayer vdW charge transfer is the source of both vertical polarization and metallicity, and these properties are closely related to the spatially extended Te-$p_z$ orbital. Finally, we reveal that electron doping can significantly adjust the vertical polarization of these FEMs in both magnitude and direction. Our findings introduce a new class of FEMs, which have potential applications in functional nanodevices such as ferroelectric tunneling junction and nonvolatile ferroelectric memory.

Aperiodic dynamical quantum phase transitions in multi-band Bloch Hamiltonian and its origin. (arXiv:2303.15966v3 [cond-mat.stat-mech] UPDATED)
Kaiyuan Cao, Hao Guo, Guangwen Yang

We study the dynamical quantum phase transition (DQPT) in the multi-band Bloch Hamiltonian of the one-dimensional periodic Kitaev model following a quench from a Bloch band. Using a combination of dynamical free energy and Pancharatnam geometric phase analysis, we demonstrate that the critical times of DQPTs are not periodically spaced due to the deviation of critical momentum caused by the multi-band effect, which differs from the results found in two-band models. We propose a geometric interpretation to explain the non-uniformly spaced critical times. Additionally, we clarify the conditions necessary for the occurrence of the DQPT in the multi-band Bloch Hamiltonian. We find that only the quench from the Bloch states, which causes the band gap to collapse at the critical point, can induce a DQPT after crossing the quantum phase transition. Otherwise, the DQPT will not occur. Furthermore, we confirm that the dynamical topological order parameter, which is defined by the winding number of the Pancharatnam geometric phase, is not quantized due to the periodic modulation but still displays discontinuous jumps at the critical times of DQPTs. In addition, we extend our theory to mixed-state DQPT and find that the DQPT is absent at non-zero temperatures.

Topological triple phase transition in non-Hermitian quasicrystals with complex asymmetric hopping. (arXiv:2306.14987v2 [cond-mat.dis-nn] UPDATED)
Shaina Gandhi, Jayendra N. Bandyopadhyay

The triple phase transitions or simultaneous transitions of three different phases, namely topological, parity-time (PT) symmetry breaking, and metal-insulator transitions, are observed in an extension of PT symmetric non-Hermitian Aubry-Andr\'e-Harper model. In this model, besides non-Hermitian complex quasi-periodic onsite potential, non-Hermiticity is also included in the nearest-neighbor hopping terms. Moreover, the nearest-neighbor hopping terms is also quasi-periodic. The presence of two non-Hermitian parameters, one from the onsite potential and another one from the hopping part, ensures PT symmetry transition in the system. In addition, tuning these two non-Hermitian parameters, we identify a parameters regime, where we observe the triple phase transition. Following some recent studies, an electrical circuit based experimental realization of this model is also discussed.

Symmetric Mass Generation of K\"ahler-Dirac Fermions from the Perspective of Symmetry-Protected Topological Phases. (arXiv:2306.17420v4 [cond-mat.str-el] UPDATED)
Yuxuan Guo, Yi-Zhuang You

The K\"ahler-Dirac fermion, recognized as an elegant geometric approach, offers an alternative to traditional representations of relativistic fermions. Recent studies have demonstrated that symmetric mass generation (SMG) can precisely occur with two copies of K\"ahler-Dirac fermions across any spacetime dimensions. This conclusion stems from the study of anomaly cancellation within the fermion system. Our research provides an alternative understanding of this phenomenon from a condensed matter perspective, by associating the interacting K\"ahler-Dirac fermion with the boundary of bosonic symmetry-protected topological (SPT) phases. We show that the low-energy bosonic fluctuations in a single copy of the K\"ahler-Dirac fermion can be mapped to the boundary modes of a $\mathbb{Z}_2$-classified bosonic SPT state, protected by an inversion symmetry universally across all dimensions. This implies that two copies of K\"ahler-Dirac fermions can always undergo SMG through interactions mediated by these bosonic modes. This picture aids in systematically designing SMG interactions for K\"ahler-Dirac fermions in any dimension. We present the exact lattice Hamiltonian of these interactions and validate their efficacy in driving SMG.

Found 8 papers in prb
Date of feed: Tue, 11 Jul 2023 03:17:05 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]+)

Spin-valley dependent double Andreev reflections in the proximitized graphene/superconductor junction
Lu Gao, Qiang Cheng, and Qing-Feng Sun
Author(s): Lu Gao, Qiang Cheng, and Qing-Feng Sun

We study the Andreev reflections and the quantum transport in the proximitized graphene/superconductor junction. The proximitized graphene possesses the pseudospin staggered potential and the intrinsic spin-orbit coupling induced by substrate, which are responsible for the spin-valley dependent doub…

[Phys. Rev. B 108, 024504] Published Mon Jul 10, 2023

Tunneling spectra of impurity states in unconventional superconductors
P. O. Sukhachov, Felix von Oppen, and L. I. Glazman
Author(s): P. O. Sukhachov, Felix von Oppen, and L. I. Glazman

We investigate the role of the Bloch functions and superconducting gap symmetries on the formation and properties of impurity-induced resonances in a two-dimensional superconductor, and elucidate their manifestation in scanning tunneling spectra. We use and extend a recently developed scattering app…

[Phys. Rev. B 108, 024505] Published Mon Jul 10, 2023

Accurate prediction of migration barrier of oxygen vacancy in ${\mathrm{PrMnO}}_{3}$ and ${\mathrm{CaMnO}}_{3}$: Explaining experimental results with density functional theory
Shashank V. Inge, Adityanarayan Pandey, Udayan Ganguly, and Amrita Bhattacharya
Author(s): Shashank V. Inge, Adityanarayan Pandey, Udayan Ganguly, and Amrita Bhattacharya

Resistive-switching-based memory is a popular research area for majorly neuromorphic, nonvolatile memory design and in-memory computing. ${\mathrm{Pr}}_{1−x}{\mathrm{Ca}}_{x}{\mathrm{MnO}}_{\text{3}}$ [$\mathrm{PCMO}(x$)] is one of the most explored perovskite materials for resistive random access m…

[Phys. Rev. B 108, 035114] Published Mon Jul 10, 2023

Layer-by-layer disentangling two-dimensional topological quantum codes
Mohammad Hossein Zarei and Mohsen Rahmani Haghighi
Author(s): Mohammad Hossein Zarei and Mohsen Rahmani Haghighi

While local unitary transformations are used for identifying quantum states that are in the same topological class, nonlocal unitary transformations are also important for studying the transition between different topological classes. In particular, it is an important task to find suitable nonlocal …

[Phys. Rev. B 108, 035116] Published Mon Jul 10, 2023

Nonlinear magnetotransport in a two-dimensional system with merging Dirac points
Ojasvi Pal, Bashab Dey, and Tarun Kanti Ghosh
Author(s): Ojasvi Pal, Bashab Dey, and Tarun Kanti Ghosh

We study the linear, second-order nonlinear (NL) current and voltage responses of a two-dimensional gapped semi-Dirac system with merging Dirac nodes along the $x$ direction under the influence of a weak magnetic field $(B)$, using the semiclassical Boltzmann formalism. We investigate the effect of …

[Phys. Rev. B 108, 035203] Published Mon Jul 10, 2023

Multiconfigurational nature of electron correlation within nitrogen vacancy centers in diamond
Yilin Chen, Tonghuan Jiang, Haoxiang Chen, Erxun Han, Ali Alavi, Kuang Yu, Enge Wang, and Ji Chen
Author(s): Yilin Chen, Tonghuan Jiang, Haoxiang Chen, Erxun Han, Ali Alavi, Kuang Yu, Enge Wang, and Ji Chen

Diamond is a solid-state platform used to develop quantum technologies, but it has been a long-standing problem that the current understanding of quantum states of nitrogen vacancy (NV) centers in diamond is mostly limited to single-electron pictures. Here, we combine the full configuration interact…

[Phys. Rev. B 108, 045111] Published Mon Jul 10, 2023

Charge fluctuations, phonons, and superconductivity in multilayer graphene
Ziyan Li, Xueheng Kuang, Alejandro Jimeno-Pozo, Héctor Sainz-Cruz, Zhen Zhan, Shengjun Yuan, and Francisco Guinea
Author(s): Ziyan Li, Xueheng Kuang, Alejandro Jimeno-Pozo, Héctor Sainz-Cruz, Zhen Zhan, Shengjun Yuan, and Francisco Guinea

Motivated by the recent experimental detection of superconductivity in Bernal bilayer (AB) and rhombohedral trilayer (ABC) graphene, we study the emergence of superconductivity in multilayer graphene based on a Kohn-Luttinger (KL) -like mechanism in which the pairing glue is the screened Coulomb int…

[Phys. Rev. B 108, 045404] Published Mon Jul 10, 2023

Chiral anomalies in three-dimensional spin-orbit coupled metals: Electrical, thermal, and gravitational anomalies
Sunit Das, Kamal Das, and Amit Agarwal
Author(s): Sunit Das, Kamal Das, and Amit Agarwal

The discovery of chiral anomaly in Weyl semimetals, the nonconservation of chiral charge and energy across two opposite chirality Weyl nodes, has sparked immense interest in understanding its impact on various physical phenomena. Here, we demonstrate the existence of electrical, thermal, and gravita…

[Phys. Rev. B 108, 045405] Published Mon Jul 10, 2023

Found 1 papers in prl
Date of feed: Tue, 11 Jul 2023 03:17:04 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]+)

Universal Velocity Statistics in Decaying Turbulence
Christian Küchler, Gregory P. Bewley, and Eberhard Bodenschatz
Author(s): Christian Küchler, Gregory P. Bewley, and Eberhard Bodenschatz

In turbulent flows, kinetic energy is transferred from large spatial scales to small ones, where it is converted to heat by viscosity. For strong turbulence, i.e., high Reynolds numbers, Kolmogorov conjectured in 1941 that this energy transfer is dominated by inertial forces at intermediate spatial …

[Phys. Rev. Lett. 131, 024001] Published Mon Jul 10, 2023

Found 2 papers in pr_res
Date of feed: Tue, 11 Jul 2023 03:17:05 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]+)

RKKY to Kondo crossover in helical edge of a topological insulator
Pol Alonso-Cuevillas Ferrer, Oleg M. Yevtushenko, and Andreas Weichselbaum
Author(s): Pol Alonso-Cuevillas Ferrer, Oleg M. Yevtushenko, and Andreas Weichselbaum

Two spatially separated magnetic impurities coupled to itinerant electrons give rise to a dynamically generated exchange (RKKY) inter-impurity interaction that competes with the individual Kondo screening of the impurities. It has been recently shown by Yevtushenko and Yudson [Phys. Rev. Lett. 120, …

[Phys. Rev. Research 5, 033016] Published Mon Jul 10, 2023

Correlated fractional Dirac materials
Bitan Roy and Vladimir Juričić
Author(s): Bitan Roy and Vladimir Juričić

Fractional Dirac materials, featuring a fractional energy-momentum relation, can either manifest unconventional quantum critical phenomena driven by local Hubbard-like interactions or harbor a two-fluid quantum system, with a conventional Dirac-liquid component, tuned by the long-range Coulomb interaction.

[Phys. Rev. Research 5, L032002] Published Mon Jul 10, 2023

Found 1 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]+)

Observation of flat band, Dirac nodal lines and topological surface states in Kagome superconductor CsTi3Bi5
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