Robust surface electronic properties of topological insulators: Bi_2Te_3 films grown by molecular beam epitaxy

摘要

The surface electronic properties of the important topological insulator Bi_2Te_3 are shown to be robust under an extended surface preparation procedure, which includes exposure to atmosphere and subsequent cleaning and recrystallization by an optimized in situ sputter-anneal procedure under ultrahigh vacuum conditions. Clear Dirac-cone features are displayed in high-resolution angle-resolved photoemission spectra from the resulting samples, indicating remarkable insensitivity of the topological surface state to cleaning-induced surface roughness.