Structure of surface electronic states in strained mercury telluride

O V Kibis,I A Shelykh,O Kyriienko

doi:10.1088/1367-2630/ab1406

Abstract

We present the theory describing the various surface electronic states arisen from the mixing of conduction and valence bands in a strained mercury telluride (HgTe) bulk material. We demonstrate that the strain-induced band gap in the Brillouin zone center of HgTe results in the surface states of two different kinds. Surface states of the first kind exist in the small region of electron wave vectors near the center of the Brillouin zone and have the Dirac linear electron dispersion characteristic for topological states. The surface states of the second kind exist only far from the center of the Brillouin zone and have the parabolic dispersion for large wave vectors. The structure of these surface electronic states is studied both analytically and numerically in the broad range of their parameters, aiming to develop its systematic understanding for the relevant model Hamiltonian. The results bring attention to the rich surface physics relevant for topological systems.

Highlights

The studies of two-dimensional (2D) electronic modes localized near the surface of a three-dimensional (3D) condensed matter structure represent one of the most actively studied directions of modern science of the last decade
The band structure of natural HgTe is semi-metallic: There is the small overlap of conduction and valence bands originated from the bulk inversion asymmetry of the crystal structure[19]
The characteristic feature of HgTe is the coexistence of surface electronic states of different physical nature: Besides of the discussed topological surface states in gapped HgTe, there are the surface states in gapless HgTe analyzed for the first time by D’yakonov and Khaetskii[34]

Summary

Introduction

The studies of two-dimensional (2D) electronic modes localized near the surface of a three-dimensional (3D) condensed matter structure (surface electronic states) represent one of the most actively studied directions of modern science of the last decade. In bulk strained HgTe, the states of this electronic term are described by the Hamiltonian[19] In bulk HgTe, there are the four different branches of electron energy, ε(k), corresponding to the four branches of the conduction and valence bands spin-split due to the BIA terms of the Hamiltonian (1).

Results

Conclusion