Stability of the (0001) surface of the Bi2Se3 topological insulator

Abstract

The inertness of the cleaved (0001) surface of a Bi2Se3 single crystal to oxidation has been demonstrated using X-ray photoelectron spectroscopy, as well as atomic-force and scanning tunneling microscopy and spectroscopy. No intrinsic bismuth and selenium oxides are formed on the surface after a month of storage in air. Atomically flat surfaces with macroscopic sizes (∼1 cm2) and rms roughness less than 0.1 nm have been prepared, and (1 × 1)-(0001) Bi2Se3 atomic structure has been resolved. The tunneling conductance measurements have shown that the energy dependence of the surface density of states is quasilinear in the band gap of Bi2Se3.