"Topological Insulators in Ternary Compounds with a Honeycomb Lattice"

Hai-Jun Zhang: Stanislav Chadov, Lukas Müchler, Binghai Yan, Xiao-Liang Qi, Jürgen Kübler, Shou-Cheng Zhang, and Claudia Felser; Phys. Rev. Lett., 04/11/11.

Additional Authors: Stanislav Chadov, Lukas Müchler, Binghai Yan, Xiao-Liang Qi, Jürgen Kübler, Shou-Cheng Zhang, and Claudia Felser

Abstract:

We investigate a new class of ternary materials such as LiAuSe and KHgSb with a honeycomb structure in Au-Se and Hg-Sb layers. We demonstrate the band inversion in these materials similar to HgTe, which is a strong precondition for existence of the topological surface states. In contrast with graphene, these materials exhibit strong spin-orbit coupling and a small direct band gap at the Γ point. Since these materials are centrosymmetric, it is straightforward to determine the parity of their wave functions, and hence their topological character. Surprisingly, the compound with strong spin-orbit coupling (KHgSb) is trivial, whereas LiAuSe is found to be a topological insulator.