Bulk and surface electronic structure of Bi4Te3 from GW calculations and photoemission experiments

The authors present a combined theoretical and experimental study of the electronic structure of stoichiometric Bi4Te3, a natural superlattice of alternating Bi2Te3 quintuple layers and Bi bilayers. In contrast to the related semiconducting compounds Bi2Te3 and Bi1Te1, density functional theory predicts Bi4Te3 is a semimetal. In this work, we compute the quasiparticle electronic structure of Bi4Te3 in the framework of the GW approximation within many-body perturbation theory. The quasiparticle corrections are found to modify the dispersion of the valence and conduction bands in the vicinity of the Fermi energy, leading to the opening of a small indirect band gap. Based on the analysis of the eigenstates, Bi4Te3 is classified as a dual topological insulator with bulk topological invariants Z2 (1;111) and magnetic mirror Chern number nM=1. The bulk GW results are used to build a Wannier-function-based tight-binding Hamiltonian that is further applied to study the electronic properties of the (111) surface. The comparison with our angle-resolved photoemission measurements shows excellent agreement between the computed and measured surface states and indicates the dual topological nature of Bi4Te3.

Dmitrii Nabok, Murat Tas, Shotaro Kusaka, Engin Durgun, Christoph Friedrich, Gustav Bihlmayer, Stefan Blügel, Toru Hirahara, and Irene Aguilera Phys. Rev. Materials 6, 034204

The authors present a combined theoretical and experimental study of the electronic structure of stoichiometric Bi4Te3, a natural superlattice of alternating Bi2Te3 quintuple layers and Bi bilayers. https://arxiv.org/abs/2204.08856

© 2022, The Author(s)
 

https://doi.org/10.1103/PhysRevMaterials.6.034204