Topological quantum phase transitions driven by external electric fields in Sb2Te3 thin films

TLDR: It is shown that topological quantum phase transitions are driven by external electric fields in thin films of Sb2Te3, and the band topology is identified by directly calculating the invariant from electronic wave functions.

Abstract: Using first-principles calculations, we show that topological quantum phase transitions are driven by external electric fields in thin films of Sb(2)Te(3). The film, as the applied electric field normal to its surface increases, is transformed from a normal insulator to a topological insulator or vice versa depending on the film thickness. We identify the band topology by directly calculating the Z(2) invariant from electronic wave functions. The dispersion of edge states is also found to be consistent with the bulk band topology in view of the bulk-boundary correspondence. We present possible applications of the topological phase transition as an on/off switch of the topologically protected edge states in nano-scale devices.