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arXiv · 1403.0066

The emergence of topologically protected surface states in epitaxial Bi(111) thin films

Kai Zhu·Lin Wu·Xinxin Gong·Shunhao Xiao·Shiyan Li·Xiaofeng Jin·Mengyu Yao·Dong Qian·Meng Wu·Ji Feng·Qian Niu·Fernando de Juan·Dung-Hai Lee
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Abstract

Quantum transport measurements including the Altshuler-Aronov-Spivak (AAS) and Aharonov-Bohm (AB) effects, universal conductance fluctuations (UCF), and weak anti-localization (WAL) have been carried out on epitaxial Bi thin films ($10-70$ bilayers) on Si(111). The results show that while the film interior is insulating all six surfaces of the Bi thin films are robustly metallic. We propose that these properties are the manifestation of a novel phenomenon, namely, a topologically trivial bulk system can become topologically non-trivial when it is made into a thin film. We stress that what's observed here is entirely different from the predicted 2D topological insulating state in a single bilayer Bi where only the four side surfaces should possess topologically protected gapless states.

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Kai Zhu, Lin Wu, Xinxin Gong, Shunhao Xiao, Shiyan Li, Xiaofeng Jin, Mengyu Yao, Dong Qian, Meng Wu, Ji Feng, Qian Niu, Fernando de Juan, Dung-Hai Lee. 2014-03-01. The emergence of topologically protected surface states in epitaxial Bi(111) thin films. https://arxiv.org/abs/1403.0066

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