Electron-phonon scattering and temperature dependence of electronic transport properties of PbTe from first principles

In PbTe, one of the most efficient thermoelectric materials, the temperature dependence of the mobility suggests the major role of acoustic phonon scattering [1]. However, recent studies showed that longitudinal optical (LO) phonon scattering is dominant in PbTe [2]. Here we build accurate models of electronic and phonon bands, and electron-phonon scattering from first principles. By solving the Boltzmann equation in the momentum relaxation time approximation, we calculate mobility and thermoelectric transport properties. Our approach allows us to obtain a very fine k-space resolution while significantly reducing computational cost, and study the impact of individual phonons on electronic transport. We find that polar LO scattering dominates in PbTe, while acoustic scattering is relatively weak. However, at high temperatures and doping concentrations, the non-polar LO contribution becomes appreciable, thus changing the temperature dependence of the mobility to that characteristic for acoustic phonons. Our calculated mobility and thermoelectric properties of PbTe are in very good agreement with experiments.

[1] Y. Pei et al, Adv. Energy Mater. 4, 13 (2014)
[2] Q. Song et al, Mater. Today Phys. 2, 69 (2017)