Halide (X = I, Br, Cl) doping to tune the electronic structure for conversion of Pb0.6Sn0.4Te into a high-performing thermoelectric material

Abstract

The fabrication of thermoelectric (TE) devices requires both p- and n-type legs with comparable performances. Pb_0.6Sn_0.4Te, which belongs to the class of topological crystalline insulator (TCI), has the potential to be a high-performing TE material due to its tunable electronic structure. Herein, we use first-principles electronic structure calculations for the very first time to study the electronic structure of halide-doped (X = I, Br and Cl) Pb_0.6Sn_0.4Te. We show through Boltzmann transport property calculations that the breaking of crystal mirror symmetry is not a necessary criterion for the enhancement of TE properties. A maximum attainable ZT of ∼1.42 to ∼1.51 at 800 K by tuning the chemical potential makes these materials worth studying further.