title: Maximizing the thermoelectric performance of topological insulator Bi2Te3 films in the few-quintuple layer regime.
abstract: Using first-principles calculations and the Boltzmann theory, we explore the feasibility to maximize the thermoelectric figure of merit (ZT) of topological insulator Bi2Te3 films in the few-quintuple layer regime. We discover that the delicate competitions between the surface and bulk contributions, coupled with the overall quantum size effects, lead to a novel and generic non-monotonous dependence of ZT on the film thickness. In particular, when the system crosses into the topologically non-trivial regime upon increasing the film thickness, the much longer surface relaxation time associated with the robust nature of the topological surface states results in a maximal ZT value, which can be further optimized to ∼2.0 under physically realistic conditions. We also reveal the appealing potential of bridging the long-standing ZT asymmetry of p- and n-type Bi2Te3 systems.
authors.affiliation: Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, China. phlhj@whu.edu.cn.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Liang
authors.forename: Long
authors.initials: L
authors.lastname: Cheng
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Huijun
authors.initials: H
authors.lastname: Liu
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Zhang