Impurity potential induced gap at the Dirac point of topological insulators with in-plane magnetization

M. F. Islam; Anna Pertsova; C. M. Canali

doi:10.1103/physrevb.99.155401

Discovery of a weak topological insulating state and van Hove singularity in triclinic RhBi2

Nature Communications ◽

10.1038/s41467-021-22136-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Kyungchan Lee ◽

Gunnar F. Lange ◽

Lin-Lin Wang ◽

Brinda Kuthanazhi ◽

Thaís V. Trevisan ◽

...

Keyword(s):

Time Reversal ◽

Topological Insulators ◽

Dirac Point ◽

Saddle Points ◽

Surface States ◽

Van Hove Singularity ◽

Space Group ◽

Topological Materials ◽

Topological Surface ◽

Optimal Space

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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Simultaneous observation of surface- and edge-states of a 2D topological insulator through scanning tunneling spectroscopy and differential conductance imaging

Physical Chemistry Chemical Physics ◽

10.1039/c7cp00149e ◽

2017 ◽

Vol 19 (15) ◽

pp. 9872-9878 ◽

Cited By ~ 3

Author(s):

Hrishikesh Bhunia ◽

Abhijit Bar ◽

Abhijit Bera ◽

Amlan J. Pal

Keyword(s):

Topological Insulator ◽

Fermi Energy ◽

Topological Insulators ◽

Dirac Point ◽

Scanning Tunneling Spectroscopy ◽

Tunneling Spectroscopy ◽

Differential Conductance ◽

Scanning Tunneling ◽

Edge States ◽

Simultaneous Observation

Gapless edge-states with a Dirac point below the Fermi energy and band-edges at the interior observed in 2D topological insulators.

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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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Origin of the temperature dependence of the energy gap in Cr-doped Bi2Se3

Physical Chemistry Chemical Physics ◽

10.1039/c7cp08049b ◽

2018 ◽

Vol 20 (13) ◽

pp. 8624-8628 ◽

Cited By ~ 4

Author(s):

Turgut Yilmaz ◽

William Hines ◽

Shoroog Alraddadi ◽

Joseph I. Budnick ◽

Boris Sinkovic

Keyword(s):

Temperature Dependence ◽

Topological Insulators ◽

Recent Progress ◽

Dirac Point ◽

Energy Gap ◽

Impurity Doped

Recent progress in impurity-doped topological insulators has shown that the gap at the Dirac point shrinks with reducing temperature.

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Impurity-Induced Magnetization of Graphene

Materials ◽

10.3390/ma15020526 ◽

2022 ◽

Vol 15 (2) ◽

pp. 526

Author(s):

Michał Inglot ◽

Tomasz Szczepański

Keyword(s):

Dirac Point ◽

Bessel Functions ◽

Magnetic Impurity ◽

Energy Levels ◽

Resonance Energy ◽

Coupling Constant ◽

Impurity States ◽

Impurity Potential ◽

Single Impurity ◽

Massless Fermions

We present a model of impurity-induced magnetization of graphene assuming that the main source of graphene magnetization is related to impurity states with a localized spin. The analysis of solutions of the Schrödinger equation for electrons near the Dirac point has been performed using the model of massless fermions. For a single impurity, the solution of Schrödinger’s equation is a linear combination of Bessel functions. We found resonance energy levels of the non-magnetic impurity. The magnetic moment of impurity with a localized spin was accounted for the calculation of graphene magnetization using the Green’s function formalism. The spatial distribution of induced magnetization for a single impurity is obtained. The energy of resonance states was also calculated as a function of interaction. This energy is depending on the impurity potential and the coupling constant of interaction.

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