Band Gap Size Dependence of Topological Insulator Bi2Te3 Nanotube

Abstract

We study the electronic structure of a cylindrical nanotube made of a topological insulator Bi2Te3. The calculation was made 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 done. Due to high surface-to volume ratio, a variation of nanotube geometrical sizes provides decreasing of the topological insulator band gap in 60 times compared to the corresponding bulk value. The size dependence of topological insulator nanotube band gap is mach stronger than that for the topological insulator nanowires.