First-principles study of native point defects in topological insulator Bi$_2$Se$_3$

Shuang-Xi Wang; Ping Zhang; Shu-Shen Li

paper

First-principles study of native point defects in topological insulator Bi $_{2}$ Se $_{3}$

arXiv:1201.2469

Abstract

The \emph{p}-type Bi $_{2}$ Se $_{3}$ is much desirable as a promising thermoelectric material and topological insulator, while the naturally grown Bi $_{2}$ Se $_{3}$ is always \emph{n}-type doped by native point defects. Here we use first-principles calculations to identify the origin of the \emph{n}-type tendency in bulk Bi $_{2}$ Se $_{3}$ : The Se vacancies (V $_{Se1}$ and V $_{Se2}$ ) and Se $_{Bi}$ antisite dominate the donorlike doping with low formation energy, while the predisposed Bi $_{Se1}$ defect results in the pair of V $_{Se1}$ and Bi interstitial, which is also a donor rather than an acceptor. Moreover, for Bi $_{2}$ Se $_{3}$ (111) surface, we find that the band structures modulated by the defects explicitly account for the existing experimental observations of \emph{n}-type preference.

First-principles study of native point defects in topological insulator Bi2​Se3​

Abstract

First-principles study of native point defects in topological insulator Bi $_{2}$ Se $_{3}$