Dirac electron states formed at the heterointerface between a topological insulator and a conventional semiconductor

R. Yoshimi; A. Tsukazaki; K. Kikutake; J. G. Checkelsky; K. S. Takahashi; M. Kawasaki; Y. Tokura

doi:10.1038/nmat3885

Dirac electron states formed at the heterointerface between a topological insulator and a conventional semiconductor

R. Yoshimi, A. Tsukazaki, K. Kikutake, J. G. Checkelsky, K. S. Takahashi, M. Kawasaki, Y. Tokura

Materials Property Division

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

55 Citations (Scopus)

Abstract

Topological insulators are a class of semiconductor exhibiting charge-gapped insulating behaviour in the bulk, but hosting a spin-polarized massless Dirac electron state at the surface. The presence of a topologically protected helical edge channel has been verified for the vacuum-facing surface of several topological insulators by means of angle-resolved photoemission spectroscopy and scanning tunnelling microscopy. By performing tunnelling spectroscopy on heterojunction devices composed of p-type topological insulator (Bi 1-x Sb x) 2 Te 3 and n-type conventional semiconductor InP, we report the observation of such states at the solid-state interface. Under an applied magnetic field, we observe a resonance in the tunnelling conductance through the heterojunction due to the formation of Landau levels of two-dimensional Dirac electrons at the interface. Moreover, resonant tunnelling spectroscopy reveals a systematic dependence of the Fermi velocity and Dirac point energy on the composition x. The successful formation of robust non-trivial edge channels at a solid-state interface is an essential step towards functional junctions based on topological insulators.

Original language	English
Pages (from-to)	253-257
Number of pages	5
Journal	Nature Materials
Volume	13
Issue number	3
DOIs	https://doi.org/10.1038/nmat3885
Publication status	Published - 2014 Mar

ASJC Scopus subject areas

Chemistry(all)
Materials Science(all)
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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title = "Dirac electron states formed at the heterointerface between a topological insulator and a conventional semiconductor",

abstract = "Topological insulators are a class of semiconductor exhibiting charge-gapped insulating behaviour in the bulk, but hosting a spin-polarized massless Dirac electron state at the surface. The presence of a topologically protected helical edge channel has been verified for the vacuum-facing surface of several topological insulators by means of angle-resolved photoemission spectroscopy and scanning tunnelling microscopy. By performing tunnelling spectroscopy on heterojunction devices composed of p-type topological insulator (Bi 1-x Sb x) 2 Te 3 and n-type conventional semiconductor InP, we report the observation of such states at the solid-state interface. Under an applied magnetic field, we observe a resonance in the tunnelling conductance through the heterojunction due to the formation of Landau levels of two-dimensional Dirac electrons at the interface. Moreover, resonant tunnelling spectroscopy reveals a systematic dependence of the Fermi velocity and Dirac point energy on the composition x. The successful formation of robust non-trivial edge channels at a solid-state interface is an essential step towards functional junctions based on topological insulators.",

author = "R. Yoshimi and A. Tsukazaki and K. Kikutake and Checkelsky, {J. G.} and Takahashi, {K. S.} and M. Kawasaki and Y. Tokura",

note = "Funding Information: This research was supported by the Japan Society for the Promotion of Science through the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program) on {\textquoteleft}Quantum Science on Strong Correlation{\textquoteright} initiated by the Council for Science and Technology Policy and by JSPS Grant-in-Aid for Scientific Research(S) No. 24224009 and No. 24226002.",

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doi = "10.1038/nmat3885",

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AU - Yoshimi, R.

AU - Tsukazaki, A.

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AU - Takahashi, K. S.

AU - Kawasaki, M.

AU - Tokura, Y.

N1 - Funding Information: This research was supported by the Japan Society for the Promotion of Science through the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program) on ‘Quantum Science on Strong Correlation’ initiated by the Council for Science and Technology Policy and by JSPS Grant-in-Aid for Scientific Research(S) No. 24224009 and No. 24226002.

PY - 2014/3

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N2 - Topological insulators are a class of semiconductor exhibiting charge-gapped insulating behaviour in the bulk, but hosting a spin-polarized massless Dirac electron state at the surface. The presence of a topologically protected helical edge channel has been verified for the vacuum-facing surface of several topological insulators by means of angle-resolved photoemission spectroscopy and scanning tunnelling microscopy. By performing tunnelling spectroscopy on heterojunction devices composed of p-type topological insulator (Bi 1-x Sb x) 2 Te 3 and n-type conventional semiconductor InP, we report the observation of such states at the solid-state interface. Under an applied magnetic field, we observe a resonance in the tunnelling conductance through the heterojunction due to the formation of Landau levels of two-dimensional Dirac electrons at the interface. Moreover, resonant tunnelling spectroscopy reveals a systematic dependence of the Fermi velocity and Dirac point energy on the composition x. The successful formation of robust non-trivial edge channels at a solid-state interface is an essential step towards functional junctions based on topological insulators.

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Dirac electron states formed at the heterointerface between a topological insulator and a conventional semiconductor

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