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arXiv · 2008.10343

Electron-phonon scattering and thermoelectric transport in $p$-type PbTe from first principles

Ransell D'Souza·Jiang Cao·José D. Querales-Flores·Stephen Fahy·Ivana Savić
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Abstract

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.

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Ransell D'Souza, Jiang Cao, José D. Querales-Flores, Stephen Fahy, Ivana Savić. 2020-08-24. Electron-phonon scattering and thermoelectric transport in $p$-type PbTe from first principles. https://doi.org/10.1103/physrevb.102.115204

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