Manipulating topological phase transition by strain.

First-principles calculations show that strain-induced topological phase transition is a universal phenomenon in those narrow-gap semiconductors for which the valence band maximum (VBM) and conduction band minimum (CBM) have different parities. The transition originates from the opposite responses of the VBM and CBM, whose magnitudes depend critically on the direction of the applied strain. Our work suggests that strain can play a unique role in tuning the electronic properties of topological insulators for device applications, as well as in the achievement of new topological insulators.