Band gap of a topological insulator nanotube

Abstract

We study the electronic structure of a topological insulator Bi2Te3 cylindrical nanotube. The energy spectrum was calculated in the framework of the kp theory near the Γ point of the surface Brilloiun zone. A band gap size dependence of the topological insulator nanotube was studied. A comparative analysis of the topological insulator direct band gap of Bi2Te3 and Bi2Se3 nanowires as a function of radius was performed. Due to a high surface-to-volume ratio, a variation in the ratio of the nanotube external radius to internal radius provides a 50-fold decrease in the topological insulator band gap compared to the respective bulk value. The size dependence of the topological insulator nanotube band gap is much stronger than that for the topological insulator nanowires.