Interface of topological insulator Bi₂Se₃ with As₂Te₃

Abstract

We study the topological states which appear at the interface of the topological insulator (TI) Bi2Se3 with As2Te3 which share similar size lattice constants. A Dirac-like state (DLS) with spin-momentum correlations characteristic to an edge Dirac-like state of a TI, forms at the interface. While our parity analysis shows that one should not expect a topologically protected surface state for As2Te3, the interface DLS has stronger overlap with the atoms of the As2Te3 layers, especially slightly away from the zone center. We believe that this interface DLS is the topologically protected Bi2Se3 edge state which "spills" over to the As2Te3 layers to optimize its energy.