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arXiv · 1104.0978

Stable nontrivial Z2 topology in ultrathin Bi (111) films: a first-principles study

Zheng Liu·Chao-Xing Liu·Yong-Shi Wu·Wen-Hui Duan·Feng Liu·Jian Wu
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Abstract

Recently, there have been intense efforts in searching for new topological insulator (TI) materials. Based on first-principles calculations, we find that all the ultrathin Bi (111) films are characterized by a nontrivial Z2 number independent of the film thickness, without the odd-even oscillation of topological triviality as commonly perceived. The stable nontrivial Z2 topology is retained by the concurrent band gap inversions at multiple time-reversal-invariant k-points and associated with the intermediate inter-bilayer coupling of the multi-bilayer Bi film. Our calculations further indicate that the presence of metallic surface states in thick Bi(111) films can be effectively removed by surface adsorption.

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Zheng Liu, Chao-Xing Liu, Yong-Shi Wu, Wen-Hui Duan, Feng Liu, Jian Wu. 2011-04-06. Stable nontrivial Z2 topology in ultrathin Bi (111) films: a first-principles study. https://doi.org/10.1103/physrevlett.107.136805

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