Controlling the evolution of two-dimensional electron gas states at a metal/Bi2Se3 interface

Abstract

We demonstrate that the evolution of a two-dimensional electron gas system at an interface of a metal and the model topological insulator (TI) Bi2Se3 can be controlled by choosing an appropriate kind of metal element and by applying a low temperature evaporation procedure. In particular, we find that only topological surface states (TSSs) can exist at a Mn/Bi2Se3 interface, which would be useful for implementing a TI-based device with surface current channels only. The existence of TSSs alone at the interface is confirmed by angle-resolved photoemission spectroscopy (ARPES). Based on the ARPES and core-level x-ray photoemission spectroscopy measurements, we propose a cation intercalation model to explain our findings.