Bulk and surface electronic structure of Bi4 Te3 from GW calculations and photoemission experiments

Date
2022-03-23
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Source Title
Physical Review Materials
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2475-9953
Publisher
American Physical Society
Volume
6
Issue
3
Pages
034204-1 - 034204-9
Language
English
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Article
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Abstract

We 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.

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