Topological electronic effects in exfoliated thin films of bismuth telluride

Abstract

AbstractAn important aspect of band gap engineering in 2D thin films of topological insulators is determining their surface electronic properties at various atomic terminations. In this work, the electronic structure evolution of thin films of bismuth telluride () with varying surface termination is discussed based on density functional theory. The reported electronic effects include closure of the hybridization energy band gap and distinct spatial charge localization of topological surface states on two types of defected surfaces –Te and Bi‐terminated. The observed band gap value changes periodically every five monolayers following the quintuple‐based layered structure. The studied system shares, to a large extent, the main features with thin films of bismuth selenide (), although with a stronger size effect.