Formation Dirac point and the topological surface states for HgCdTe-QW and mixed 3D HgCdTe TI

AbstractTime reversal symmetric (TRS) invariant topological insulators (TIs) fullfil a paradigmatic role in the field of topological materials, standing at the origin of its development. Apart from TRS protected strong TIs, it was realized early on that more confounding weak topological insulators (WTI) exist. WTIs depend on translational symmetry and exhibit topological surface states only in certain directions making it significantly more difficult to match the experimental success of strong TIs. We here report on the discovery of a WTI state in RhBi2 that belongs to the optimal space group P$$\bar{1}$$ 1 ¯ , which is the only space group where symmetry indicated eigenvalues enumerate all possible invariants due to absence of additional constraining crystalline symmetries. Our ARPES, DFT calculations, and effective model reveal topological surface states with saddle points that are located in the vicinity of a Dirac point resulting in a van Hove singularity (VHS) along the (100) direction close to the Fermi energy (EF). Due to the combination of exotic features, this material offers great potential as a material platform for novel quantum effects.

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Topological Surface States with Persistent High Spin Polarization across the Dirac Point inBi2Te2SeandBi2Se2Te

Physical Review Letters ◽

10.1103/physrevlett.109.166802 ◽

2012 ◽

Vol 109 (16) ◽

Cited By ~ 72

Author(s):

K. Miyamoto ◽

A. Kimura ◽

T. Okuda ◽

H. Miyahara ◽

K. Kuroda ◽

...

Keyword(s):

Spin Polarization ◽

High Spin ◽

Dirac Point ◽

Surface States ◽

High Spin Polarization ◽

Topological Surface

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Magnetizing topological surface states of Bi2Se3 with a CrI3 monolayer

Science Advances ◽

10.1126/sciadv.aaw1874 ◽

2019 ◽

Vol 5 (5) ◽

pp. eaaw1874 ◽

Cited By ~ 19

Author(s):

Yusheng Hou ◽

Jeongwoo Kim ◽

Ruqian Wu

Keyword(s):

Density Functional ◽

Topological Insulators ◽

Dirac Point ◽

Surface States ◽

Anomalous Hall Effect ◽

Spin Splitting ◽

Topological Feature ◽

Topological Parameters ◽

General Rules ◽

Topological Surface

To magnetize surfaces of topological insulators without damaging their topological feature is a crucial step for the realization of the quantum anomalous Hall effect (QAHE) and remains as a challenging task. Through density functional calculations, we found that adsorption of a semiconducting two-dimensional van der Waals (2D-vdW) ferromagnetic CrI3 monolayer can create a sizable spin splitting at the Dirac point of the topological surface states of Bi2Se3 films. Furthermore, general rules that connect different quantum and topological parameters are established through model analyses. This work provides a useful guideline for the realization of QAHE at high temperatures in heterostructures of 2D-vdW magnetic monolayers and topological insulators.

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Topological surface states and Dirac point tuning in ternary topological insulators

Physical Review B ◽

10.1103/physrevb.85.235406 ◽

2012 ◽

Vol 85 (23) ◽

Cited By ~ 125

Author(s):

M. Neupane ◽

S.-Y. Xu ◽

L. A. Wray ◽

A. Petersen ◽

R. Shankar ◽

...

Keyword(s):

Topological Insulators ◽

Dirac Point ◽

Surface States ◽

Topological Surface

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Топологические поверхностные состояния фермионов Дирака в термоэлектриках n-Bi-=SUB=-2-=/SUB=-Te-=SUB=-3-y-=/SUB=-Se-=SUB=-y-=/SUB=-

Физика и техника полупроводников ◽

10.21883/ftp.2019.05.47557.15 ◽

2019 ◽

Vol 53 (5) ◽

pp. 654

Author(s):

Л.Н. Лукьянова ◽

И.В. Макаренко ◽

О.А. Усов ◽

П.А. Дементьев

Keyword(s):

Dirac Point ◽

Energy Gap ◽

Surface States ◽

Surface Concentration ◽

Scanning Tunneling ◽

Fermi Velocity ◽

Dirac Fermions ◽

Tunneling Microscopy ◽

Topological Surface ◽

Local Distortions

Topological surface states of Dirac fermions in n-Bi2Te3−ySey thermoelectrics L.N. Lukyanova, I.V. Makarenko, O.A. Usov, P.A. Dementev Ioffe Institute, 194021 St. Petersburg, Russia Abstract In n-Bi2Te3 and n-Bi2Te3−ySey thermoelectrics, the surface states of Dirac fermions of the interlayer van der Waals plane (0001) were studied by scanning tunneling microscopy (STM) and spectroscopy. The surface morphology and modulated line profiles of the images in tunneling microscopy is determined by local distortions of the surface electron states density and depend on the composition. The Dirac point ED of the studied compositions is localized in the energy gap, and it shifts to the top of the valence band with increase of Se content in the solid solutions. The dependence between Dirac surface state parameters (the Dirac point position, the Fermi velocity, the fermion surface concentration) and thermoelectric properties (Seebeck coefficient and the power factor) is established for the thermoelectrics studied.

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Formation of Dirac point and the topological surface states inside the strained gap for mixed 3DHg1−xCdxTe

Physica E Low-dimensional Systems and Nanostructures ◽

10.1016/j.physe.2016.07.022 ◽

2016 ◽

Vol 84 ◽

pp. 407-414 ◽

Cited By ~ 7

Author(s):

Michał Marchewka

Keyword(s):

Dirac Point ◽

Surface States ◽

Topological Surface

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Superconducting topological surface states in the noncentrosymmetric bulk superconductor PbTaSe2

Science Advances ◽

10.1126/sciadv.1600894 ◽

2016 ◽

Vol 2 (11) ◽

pp. e1600894 ◽

Cited By ~ 64

Author(s):

Syu-You Guan ◽

Peng-Jen Chen ◽

Ming-Wen Chu ◽

Raman Sankar ◽

Fangcheng Chou ◽

...

Keyword(s):

Bound States ◽

Dirac Point ◽

Fault Tolerant ◽

Bulk Material ◽

Surface States ◽

Atomic Scale ◽

Edge States ◽

Quasi Particle ◽

Topological Superconductors ◽

Topological Surface

The search for topological superconductors (TSCs) is one of the most urgent contemporary problems in condensed matter systems. TSCs are characterized by a full superconducting gap in the bulk and topologically protected gapless surface (or edge) states. Within each vortex core of TSCs, there exists the zero-energy Majorana bound states, which are predicted to exhibit non-Abelian statistics and to form the basis of the fault-tolerant quantum computation. To date, no stoichiometric bulk material exhibits the required topological surface states (TSSs) at the Fermi level (EF) combined with fully gapped bulk superconductivity. We report atomic-scale visualization of the TSSs of the noncentrosymmetric fully gapped superconductor PbTaSe2. Using quasi-particle scattering interference imaging, we find two TSSs with a Dirac point atE≅ 1.0 eV, of which the inner TSS and the partial outer TSS crossEF, on the Pb-terminated surface of this fully gapped superconductor. This discovery reveals PbTaSe2as a promising candidate for TSC.

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Раскрытие энергетической щели в области точки Дирака при осаждении кобальта на поверхность (0001) топологического изолятора BiSbTeSe-=SUB=-2-=/SUB=-

Физика и техника полупроводников ◽

10.21883/ftp.2020.09.49821.13 ◽

2020 ◽

Vol 54 (9) ◽

pp. 859

Author(s):

А.К. Кавеев ◽

А.Г Банщиков ◽

А.Н Терпицкий ◽

В.А Голяшов ◽

О.Е Терещенко ◽

...

Keyword(s):

Molecular Beam Epitaxy ◽

Room Temperature ◽

Molecular Beam ◽

Dirac Point ◽

Surface States ◽

Energy Band Gap ◽

Temperature Dependent ◽

Molecular Beam Epitaxy Method ◽

Topological Surface ◽

First Time

It was shown for the first time that Co subnanometer coaverage, being deposited by molecular beam epitaxy method onto the (0001) surface of the BiSbTeSe2 topological insulator at 330 °C, opens an energy band gap in the spectrum of topological surface states in the region of the Dirac point, with a shift in the position of the Dirac point caused by preliminary deposition of the adsorbate at room temperature. The gap band width is 21 +/- 6 meV. Temperature-dependent measurements in the 15-150 K range did not show any width changes.

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