Ab initio study of topological surface states of strained HgTe

¹ Max Planck Institute for Chemical Physics of Solids - D-01187 Dresden, Germany
² Max Planck Institute for Physics of Complex Systems - D-01187 Dresden, Germany

^(a) yan@cpfs.mpg.de

Received: 18 August 2014
Accepted: 20 August 2014

Abstract

The topological surface states of mercury telluride (HgTe) are studied by ab initio calculations assuming different strains and surface terminations. For the Te-terminated surface, a single Dirac cone exists at the Γ-point. The Dirac point shifts up from the bulk valence bands into the energy gap when the substrate-induced strain increases. At the experimental strain value (0.3%), the Dirac point lies slightly below the bulk valence band maximum. A left-handed spin texture was observed in the upper Dirac cone, similar to that of the Bi₂Se₃-type topological insulator. For the Hg-terminated surface, three Dirac cones appear at three time-reversal–invariant momenta, excluding the Γ-point, with non-trivial spin textures.