Thermoelectric Properties of PbTe, SnTe, and GeTe at High Pressure: an Ab Initio Study

In this work we present an ab initio study of the transport properties of PbTe, SnTe, and GeTe crystals in the B1 structure under zero and high pressure and analyze the possibility of pressure-induced thermoelectric performance enhancement. GeTe displays higher thermoelectric coefficients in both the p- and n-doping cases at zero pressure, but with applied pressure they drop quickly. n-Type SnTe has a higher Seebeck coefficient and figure of merit (ZT) than p-type SnTe at ambient conditions. With increased pressure its thermoelectric performance is improved initially and degrades later. The highest ZT appears at about 5 GPa. p-Type PbTe possesses attractive thermoelectric properties at zero pressure. With pressure applied, the ZT of this material undergoes a decline–climb–decline variation, and the optimal ZT occurs at 8 GPa to 10 GPa. Thermoelectric properties of n-type PbTe degrade slightly with increasing pressure and improve later; the improvement can be observed for pressures up to 20 GPa. These results suggest possible enhancement of thermoelectric properties for SnTe under intermediate pressure and PbTe under high pressure.