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

doi:10.1103/PhysRevB.93.165123

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

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

14 Citations (Scopus)

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.

Original language	English
Article number	165123
Journal	Physical Review B
Volume	93
Issue number	16
DOIs	https://doi.org/10.1103/PhysRevB.93.165123
Publication status	Published - 18 Apr 2016
Externally published	Yes

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

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.",

author = "Trang, {Chi Xuan} and Zhiwei Wang and Keiko Yamada and Seigo Souma and Takafumi Sato and Takashi Takahashi and Kouji Segawa and Yoichi Ando",

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AU - Trang, Chi Xuan

AU - Wang, Zhiwei

AU - Yamada, Keiko

AU - Souma, Seigo

AU - Sato, Takafumi

AU - Takahashi, Takashi

AU - Segawa, Kouji

AU - Ando, Yoichi

PY - 2016/4/18

Y1 - 2016/4/18

N2 - 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.

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

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