Atomic and electronic structure of bismuth-bilayer-terminated Bi2Se3(0001) prepared by atomic hydrogen etching

Abstract

A bilayer of bismuth is recognized as a prototype two-dimensional topological insulator. Here we present a simple and well reproducible top-down approach to prepare a flat and well ordered bismuth bilayer with a lateral size of several hundred nanometers on Bi2Se3(0001). Using scanning tunneling microscopy, surface x-ray diffraction, and Auger electron spectroscopy we show that exposure of Bi2Se3(0001) to atomic hydrogen completely removes selenium from the top quintuple layer. The band structure of the system, calculated from first principles for the experimentally derived atomic structure, is in excellent agreement with recent photoemission data. Our results open interesting perspectives for the study of topological insulators in general.