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Related papers: Bulk metals with helical surface states

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Topological edge modes are excitations that are localized at the materials' edges and yet are characterized by a topological invariant defined in the bulk. Such bulk-edge correspondence has enabled the creation of robust electronic,…

Mesoscale and Nanoscale Physics · Physics 2020-11-30 Ananya Ghatak , Martin Brandenbourger , Jasper van Wezel , Corentin Coulais

We experimentally demonstrate boundary-induced helical bulk states (BI-HBSs) for RF acoustic transport in LiNbO3 thin-film phononic crystals (approximately 175-200 MHz). A boundary-symmetry selection rule at an accidental {\Gamma}-point…

Previous studies have shown that the bulk topology of single-particle systems can be captured by the band inversion surface or by the spin inversion surface emerged on the time-averaged spin polarization. Most of the studies, however, are…

Strongly Correlated Electrons · Physics 2023-01-12 Rui Wu , Panpan Fang , Chen Sun , Fuxiang Li

We analyze the probability density distribution in a topological insulator slab of finite thickness, where the bulk and surface states are allowed to hybridize. By using an effective continuum Hamiltonian approach as a theoretical…

Mesoscale and Nanoscale Physics · Physics 2023-12-11 Jorge David Castaño-Yepes , Enrique Muñoz

Topological insulators are a recently discovered class of materials with fascinating properties: While the inside of the solid is insulating, fundamental symmetry considerations require the surfaces to be metallic. The metallic surface…

Flocking models with metric and topological interactions are supposed to exhibit distinct features, as for instance the presence and absence of moving polar bands. On the other hand, quenched disorder (spatial heterogeneities) has been…

Biological Physics · Physics 2022-01-04 Parisa Rahmani , Fernando Peruani , Pawel Romanczuk

We study the surface states of a strongly coupled Weyl semimetal within holography. By explicit numerical computation of an inhomogeneous holographic Weyl semimetal we observe the appearance of an electric current restricted to the surface…

High Energy Physics - Theory · Physics 2017-09-07 Martin Ammon , Markus Heinrich , Amadeo Jiménez-Alba , Sebastian Moeckel

In this work we study many-body 'steady states' that arise in the non-Hermitian generalisation of the non-interacting Su-Schrieffer-Heeger model at a finite density of fermions. We find that the hitherto known phase diagrams for this…

Mesoscale and Nanoscale Physics · Physics 2022-05-17 Ayan Banerjee , Suraj S. Hegde , Adhip Agarwala , Awadhesh Narayan

We have investigated the surface states of a potential mixed-valent topological insulator SmB$_6$ based on the first principles density functional theory slab band structure analysis. We have found that metallic surface states are formed in…

Strongly Correlated Electrons · Physics 2015-06-19 Junwon Kim , Kyoo Kim , Chang-Jong Kang , Sooran Kim , Hong Chul Choi , J. -S. Kang , J. D. Denlinger , B. I. Min

Topological phases of matter have been extensively studied for their intriguing bulk and edge properties. Recently, higher-order topological insulators with boundary states that are two or more dimensions lower than the bulk states, have…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 Xiujuan Zhang , Bi-Ye Xie , Hong-Fei Wang , Xiangyuan Xu , Yuan Tian , Jian-Hua Jiang , Ming-Hui Lu , Yan-Feng Chen

We consider asymmetric and symmetric dimerized two-leg ladders, comprising of four different lattice points per unit cell, illuminated by circularly polarized light. In the asymmetric dimerized ladder case, rungs are not perpendicular to…

Mesoscale and Nanoscale Physics · Physics 2020-09-08 Milad Jangjan , Mir Vahid Hosseini

We present a quantitative microscopic theory of the disorder- and phonon-induced coupling between surface and bulk states in topological insulator (TI) films. We find a simple structure for the surface-to-bulk scattering matrix elements and…

Strongly Correlated Electrons · Physics 2015-01-20 Kush Saha , Ion Garate

Topological insulators, along with Chern insulators and Quantum Hall insulator phases, are considered as paradigms for symmetry protected topological phases of matter. This article reports the experimental realization of the time-reversal…

Mesoscale and Nanoscale Physics · Physics 2021-01-01 Priya Tiwari , Saurabh Kumar Srivastav , Sujay Ray , Tanmoy Das , Aveek Bid

We calculate the magnetization of the helical metallic surface states of a topological insulator. We account for the presence of a small sub-dominant Schr{\"o}dinger piece in the Hamiltonian in addition to the dominant Dirac contribution.…

Mesoscale and Nanoscale Physics · Physics 2014-12-01 Calvin J. Tabert , J. P. Carbotte

A key challenge in condensed matter research is the optimization of topological insulator (TI) compounds for the study and future application of their unique surface states. Truly insulating bulk states would allow the exploitation of…

The protected helical surface states in thin films of topological insulators (TI) are subject to inter-surface hybridisation. This leads to gap opening and spin texture changes as witnessed in photoemission and quasiparticle interference…

Materials Science · Physics 2021-11-23 Peter Thalmeier , Alireza Akbari

When electrons are subject to a large external magnetic field, the conventional charge quantum Hall effect \cite{Klitzing,Tsui} dictates that an electronic excitation gap is generated in the sample bulk, but metallic conduction is permitted…

Mesoscale and Nanoscale Physics · Physics 2009-10-08 D. Hsieh , D. Qian , L. Wray , Y. Xia , Y. S. Hor , R. J. Cava , M. Z. Hasan

We investigated the electronic properties of the topological insulator Bi$_{2}$Te$_{3}$ by scanning tunneling microscopy and spectroscopy at low temperature. We obtained high-resolution quasiparticle interference data of the topological…

Topological insulators are ideally represented as having an insulating bulk with topologically protected, spin-textured surface states. However, it is increasingly becoming clear that these surface transport channels can be accompanied by a…

Mesoscale and Nanoscale Physics · Physics 2017-07-28 E. K. de Vries , S. Pezzini , M. J. Meijer , N. Koirala , M. Salehi , J. Moon , S. Oh , S. Wiedmann , T. Banerjee

We show that the topologically protected flat band emerging on a surface of a nodal fermionic system promotes the surface superconductivity due to an infinitely large density of states associated with the flat band. The critical temperature…

Superconductivity · Physics 2015-05-27 N. B. Kopnin , T. T. Heikkilä , G. E. Volovik