"Model Hamiltonian for topological insulators"

Chao-Xing Liu: Xiao-Liang Qi, HaiJun Zhang, Xi Dai, Zhong Fang, and Shou-Cheng Zhang; Phys. Rev. B, 07/26/10.

Additional Authors: Xiao-Liang Qi, HaiJun Zhang, Xi Dai, Zhong Fang, and Shou-Cheng Zhang

Abstract:

In this paper we give the full microscopic derivation of the model Hamiltonian for the three-dimensional topological insulators in the Bi2Se3 family of materials (Bi2Se3, Bi2Te3 and Sb2Te3). We first give a physical picture to understand the electronic structure by analyzing atomic orbitals and applying symmetry principles. Subsequently, we give the full microscopic derivation of the model Hamiltonian introduced by Zhang et al. Nat. Phys. 5 438 (2009) based both on symmetry principles and the k⋅p perturbation theory. Two different types of k3 terms, which break the in-plane full rotation symmetry down to threefold rotation symmetry, are taken into account. An effective Hamiltonian is derived for the topological surface states. Both bulk and surface models are investigated in the presence of an external magnetic field, and the associated Landau level structure is presented. For a more quantitative fitting to the first principle calculations, we also present a model Hamiltonian including eight energy bands.