Strain-induced topological insulating behavior in ternary chalcogenide Ge₂Sb₂Te₅

¹ Department of Materials Science and Engineering, College of Materials, Xiamen University 361005 Xiamen, China
² Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Xiamen University 361005 Xiamen, China
³ Department of Physics and Astronomy, Condensed Matter Theory Group - Box 520, 75120 Uppsala, Sweden, EU
⁴ Department of Materials and Engineering, Royal Institute of Technology - 10044 Stockholm, Sweden, EU

^a zmsun@xmu.edu.cn
^b zhmsun2@yahoo.com

Received: 6 October 2011
Accepted: 30 November 2011

Abstract

We unraveled the strain-induced topological insulating behavior in Ge₂Sb₂Te₅ (GST) by means of ab initio calculations. The semiconductor–to–topological-insulator (TI) transition of Ge₂Sb₂Te₅ were induced by the strains along the ⟨ 100⟩ and ⟨ 110⟩ direction as well as the shear strains. Ge₂Sb₂Te₅ exhibits three types of TI-characterized conducting surface states: the single Dirac cone feature, the odd band-type and the Bi₂Se₃-type. The physical origin of the semiconductor-TI transition is the strain-induced inversion of the characterizations of conduction band minimum and valence band maximum with spin-orbit coupling. The present results suggest that GST-related materials are a new family of strain-induced TI.