Moiré superlattices at the topological insulator Bi₂Te₃

We report on the observation of complex superlattices at the surface of the topological insulator Bi 2 Te 3. Scanning tunneling microscopy reveals the existence of two different periodic structures in addition to the Bi 2 Te 3 atomic lattice, which is found to strongly affect the local electronic structure. These three different periodicities are interpreted to result from a single small in-plane rotation of the topmost quintuple layer only. Density functional theory calculations support the observed increase in the DOS near the Fermi level, and exclude the possibility that strain is at the origin of the observed Moiré pattern. Exploration of Moiré superlattices formed by the quintuple layers of topological insulators holds great potential for further tuning of the properties of topological insulators.