Surface lattice vibration and electron-phonon interaction in topological insulator Bi2Te3 (111) films from first principles

Surface phonon and electron-phonon (EP) interaction in Bi2Te3 (111) films are calculated by including spin-orbit coupling from the density-functional perturbation theory. We present a detailed analysis of the zone-center phonons by considering the interlayer relaxation of the films. The phonon density of states and the localized surface phonon modes along the (Gamma M) over bar and (Gamma K) over bar directions in the surface Brillouin zone are given. Our results clearly show that softening and stiffening of the surface phonons coexist in Bi2Te3 ultrathin films. Furthermore, we report on a first-principles study of the EP coupling constant for Bi2Te3 films. Our calculated EP interaction in Bi2Te3 films is very weak, which is in favor of application for room temperature electronic devices. Copyright (c) EPLA, 2012