Gate control of surface transport in MBE-grown topological insulator (Bi 1-xSb x) 2Te 3 thin films

Sunao Shimizu, Ryutaro Yoshimi, Takafumi Hatano, Kei S. Takahashi, Atsushi Tsukazaki, Masashi Kawasaki, Yoshihiro Iwasa, Yoshinori Tokura

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Topological insulators are quantum materials comprised of an insulating bulk gap and topologically protected metallic surfaces with a Dirac-like band dispersion. To access the Dirac point by transport measurements is a very challenging issue faced in current investigations of these materials. Here we report the electronic state modulation in topological insulator (Bi 1-xSb x) 2Te 3 thin films by means of an ionic-liquid gating. The films with 20 nm thickness were grown on lattice-matched semi-insulating InP substrates by molecular beam epitaxy; the temperature dependencies of resistance of these films clearly indicate their insulating bulk and metallic surface characteristics. The surface state carriers were systematically controlled by using electric-double-layer transistor (EDLT) configurations with ionic-liquid dielectrics. It was demonstrated that the surface state in the (Bi 1-xSb x) 2Te 3-based EDLTs is tuned across the Dirac point, showing ambipolar transport in a topological transport regime.

Original languageEnglish
Article number045319
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number4
Publication statusPublished - 2012 Jul 27
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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