Get access

Emerging topological insulating phase in Ge[BOND]Sb[BOND]Te compounds

Authors

  • Jeongwoo Kim,

    1. Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
    Search for more papers by this author
  • Seung-Hoon Jhi

    Corresponding author
    1. Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
    2. Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
    • Phone: +82-54-279-2094, Fax: +82-54-279-3099
    Search for more papers by this author

  • Dedicated to Stanford R. Ovshinsky on the occasion of his 90th birthday

Abstract

The electronic property of Ge[BOND]Sb[BOND]Te compounds is studied within the notion of their topological insulating phase. We show that these compounds, as pseudo-binary alloys of GeTe and Sb2Te3, in their crystalline phase with well-ordered layer stacking have imbedded surface-like states originating from topological insulating Sb2Te3 at interfaces between GeTe and Sb2Te3 layers. We demonstrate that these conducting states can significantly affect the electrical conduction of the compounds and are sensitive to Ge migration. Using first-principles methods, we show that the topological insulating phase of Ge[BOND]Sb[BOND]Te compounds can be manipulated by controlling the composition and/or layer thickness. It is found that the interaction between the surface-like states intervened by insulating GeTe layers creates an inversion gap to turn the compounds into topological insulating phase. We anticipate that the topological insulating property of Ge[BOND]Sb[BOND]Te can provide new insight into understanding the underlying physics in structural transitions of the compounds and a perspective of utilizing phase change materials as spin-control devices as well as non-volatile memory devices.

Ancillary