Doping-dependent thermopower of PbTe from Boltzmann transport calculations

The thermopower of PbTe as a function of temperature and doping level is reported based on Boltzmann transport calculations using the first principles relativistic electronic structure as obtained with the Engel-Vosko generalized gradient approximation. The results are discussed in relation to experimental data. For p-type material there is an enhancement at high-doping levels due to the onset of an increased density of states starting similar to 0.2 eV below the valence band edge. This leads to agreement between the calculated thermopower and recent results on PbTe with heavy Tl doping.