Abstract
We perform first-principles calculations to study the stability and electronic structure of the (111) surface of SnTe, a representative topological crystalline insulator (TCI). We find three stable surface phases, which support two qualitatively different types of topological surface states: type I with four Dirac points at and three points and type II with two Dirac points nearby but not at . Their appearance can be controlled by varying growth conditions. Under an Sn-poor condition, the Te-terminated surface without reconstruction is stable, resulting in the type-I surface states. While under an Sn-rich condition, the (21)-reconstructed Sn-terminated surface becomes more stable. The reconstruction folds the surface Brillouin zone and effectively induces interactions between the Dirac points at the and points. Surface states thus change from type I to type II accompanied by a Lifshitz transition. Under intermediate growth conditions, the ()-reconstructed Sn-terminated surface gets stabilized, which recovers the type-I surface states. Our work suggests a promising alternative way to control the topological surface states of TCIs besides selecting different surface orientations.
- Received 21 November 2013
- Revised 11 March 2014
DOI:https://doi.org/10.1103/PhysRevB.89.125308
©2014 American Physical Society