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 nontrivial spin textures.
@article{arxiv.1404.6085,
title = {Ab initio study of topological surface states of strained HgTe},
author = {Shu-Chun Wu and Binghai Yan and Claudia Felser},
journal= {arXiv preprint arXiv:1404.6085},
year = {2014}
}