We present a first principles based model of electron-phonon scattering mechanisms and thermoelectric transport at the L and Σ valleys in <200b>p-type PbTe, accounting for their thermally induced shifts. Our calculated values of all thermoelectric transport parameters at room temperature are in very good agreement with experiments for a wide range of doping concentrations. Scattering due to longitudinal optical phonons is the main scattering mechanism in p-type PbTe, while scattering due to transverse optical modes is the weakest. The L valleys contribute most to thermoelectric transport at 300 K due to the sizeable energy difference between the L and Σ valleys. We show that both scattering between the L and Σ valleys and additional transport channels of the Σ valleys are beneficial for the overall thermoelectric performance of p-type PbTe at 300 K. Our findings thus support the idea that materials with high valley degeneracy may be good thermoelectrics.
@article{arxiv.2008.10343,
title = {Electron-phonon scattering and thermoelectric transport in $p$-type PbTe from first principles},
author = {Ransell D'Souza and Jiang Cao and José D. Querales-Flores and Stephen Fahy and Ivana Savić},
journal= {arXiv preprint arXiv:2008.10343},
year = {2020}
}