Effect of hydrostatic pressure on the thermoelectric properties of Bi2 Te3

Abstract

We use first-principles calculations to understand the behavior of the Seebeck coefficient (S) in Bi2Te3 as a function of isotropic pressure. We perform calculations up to 5 GPa using density functional theory and with thermoelectric properties extracted using Boltzmann transport equations. We find that with the increase in pressure the system becomes more metallic, in agreement with previous calculations on Sb2Te3. For p-type doping the overall behavior is a decrease in S with an increase in pressure. At small values of hole doping (p=1.8×1018cm-3), we obtain an anomalous variation of S under 2 GPa, which is an indication of the electronic topological transition. For n-type doping, S slightly increases with pressure.