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

Research output: Contribution to journalArticlepeer-review

51 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 languageEnglish
Pages (from-to)253-257
Number of pages5
JournalNature Materials
Volume13
Issue number3
DOIs
Publication statusPublished - 2014 Mar

ASJC Scopus subject areas

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

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