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arXiv · 1206.7043

Manipulation of Topological States and Bulk Band Gap Using Natural Heterostructures of a Topological Insulator

K. Nakayama·K. Eto·Y. Tanaka·T. Sato·S. Souma·T. Takahashi·Kouji Segawa·Yoichi Ando
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Abstract

We have performed angle-resolved photoemission spectroscopy on (PbSe)5(Bi2Se3)3m, which forms a natural multilayer heterostructure consisting of a topological insulator (TI) and an ordinary insulator. For m = 2, we observed a gapped Dirac-cone state within the bulk-band gap, suggesting that the topological interface states are effectively encapsulated by block layers; furthermore, it was found that the quantum confinement effect of the band dispersions of Bi2Se3 layers enhances the effective bulk-band gap to 0.5 eV, the largest ever observed in TIs. In addition, we found that the system is no longer in the topological phase at m = 1, pointing to a topological phase transition between m = 1 and 2. These results demonstrate that utilization of naturally-occurring heterostructures is a new promising strategy for realizing exotic quantum phenomena and device applications of TIs.

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K. Nakayama, K. Eto, Y. Tanaka, T. Sato, S. Souma, T. Takahashi, Kouji Segawa, Yoichi Ando. 2012-06-29. Manipulation of Topological States and Bulk Band Gap Using Natural Heterostructures of a Topological Insulator. https://doi.org/10.1103/physrevlett.109.236804

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