Surface states and edge states of topologica...

Topological insulator is a new kind of topological material. Its body state is an insulating state with band gap, while its surface state (or edge state) is a metal state without band gap and protected by topology.

Bi2Se3 is proposed to be a kind of three-dimensional topological insulator, and it is confirmed by angle resolved photoelectron spectroscopy that Bi2Se3 is a three-dimensional topological insulator with Dirac conical surface electronic structure. However, the chemical properties of this kind of materials are complex, and there are usually various crystal defects in the actual crystals, such as Se vacancy, Bi occupying se (or Te) to form anti-site defects, etc., which le