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arXiv · 1606.08252

Metal-insulator transition and tunable Dirac-cone surface state in the topological insulator TlBi1-xSbxTe2 studied by angle-resolved photoemission

Chi Xuan Trang·Zhiwei Wang·Keiko Yamada·Seigo Souma·Takafumi Sato·Takashi Takahashi·Kouji Segawa·Yoichi Ando
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Abstract

We report a systematic angle-resolved photoemission spectroscopy on topological insulator (TI) TlBi1-xSbxTe2 which is bulk insulating at 0.5 < x < 0.9 and undergoes a metal-insulator-metal transition with the Sb content x. We found that this transition is characterized by a systematic hole doping with increasing x, which results in the Fermi-level crossings of the bulk conduction and valence bands at x~ 0 and x~1, respectively. The Dirac point of the topological surface state is gradually isolated from the valence-band edge, accompanied by a sign reversal of Dirac carriers. We also found that the Dirac velocity is the largest among known solid-solution TI systems. The TlBi1-xSbxTe2 system thus provides an excellent platform for Dirac-cone engineering and device applications of TIs.

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Chi Xuan Trang, Zhiwei Wang, Keiko Yamada, Seigo Souma, Takafumi Sato, Takashi Takahashi, Kouji Segawa, Yoichi Ando. 2016-06-27. Metal-insulator transition and tunable Dirac-cone surface state in the topological insulator TlBi1-xSbxTe2 studied by angle-resolved photoemission. https://doi.org/10.1103/physrevb.93.165123

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