Interplay of Topological States on TI/TCI Interfaces.

Tatiana V Menshchikova,Evgueni V Chulkov,Sergey V Eremeev,Vladimir M Kuznetsov

doi:10.3390/ma13204481

Abstract

Based on first-principles calculations, we study electronic structure of interfaces between a topological insulator (TI) SnBiTe and a topological crystalline insulator (TCI) SnTe. We consider two interface models characterized by the different atomic structure on the contact of the SnTe(111) and SnBiTe(0001) slabs: the model when two materials are connected without intermixing (abrupt type of interface) and the interface model predicted to be realized at epitaxial immersion growth on topological insulator substrates (smooth interface). We find that a strong potential gradient at the abrupt interface leads to the redistribution of the topological states deeper from the interface plane which prevents the annihilation of the Dirac states, predicted earlier. In contrast, a smooth interface is characterized by minor charge transfer, which promotes the strong interplay between TI and TCI Dirac cones leading to their complete annihilation.The topologically protected Dirac state of SnTe(111) survives irrespective of the interface structure.

Highlights

In the last decade, the strong impact of topology on electronic structure of many materials and related properties such as novel spin textures, surface and edge Dirac states, magnetic properties in two- and three-dimensional topological insulators, spin and charge transport as well as exotic superconducting states have been actively discussed [1,2,3,4,5,6,7,8]
We have studied the electronic structure of two structural types of Ti/topological crystalline insulator (TCI) interface
The second one is the smooth interface predicted to be realized at epitaxial immersion growth on topological insulator substrates

Summary

Introduction

The strong impact of topology on electronic structure of many materials and related properties such as novel spin textures, surface and edge Dirac states, magnetic properties in two- and three-dimensional topological insulators, spin and charge transport as well as exotic superconducting states have been actively discussed [1,2,3,4,5,6,7,8]. The first class of such materials belongs to the Z2 topological insulator phase This phase is characterized by emergence of a single Dirac surface state in an inverted bulk energy gap which is topologically protected by the time-reversal symmetry. The second class of materials represents so-called topological crystalline insulators in which even the number of gapless surface states are protected by the crystal mirror symmetry [10]. The nontrivial electronic band structure of SnTe arises from band inversion at the L points of the bulk Brillouin zone combined with the mirror symmetry in the rocksalt f cc crystal structure with respect to the (110) plane. Owing to the non-trivial topology of the bulk band structure, the gapless surface states should arise on (001), (111), and (110) surfaces, which preserve the mirror

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Results

Conclusion