Peng-Fei Zhang, Zheng Liu, Wenhui Duan, Jian Wu
Based on first-principles calculations, the electronic properties of Sb (111) films are found to undergo three transitions as a function of the film thickness. Being a topological semimetal with large enough thickness as the three-dimension limit, the film transforms to a topological insulator below 78 {\AA} (22-bilayer). A crossover from the topological insulator phase to the quantum spin hall phase occurs around 27 {\AA} (8-bilayer), due to the coupling between the upper and bottom surfaces. To the two-dimension limit, the film degrades into a trivial semiconductor below 13 {\AA} (4-bilayer), as a result of the quantum-confinement-induced level crossings.
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http://arxiv.org/abs/1203.3379
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