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

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D'Souza, Ransell
Cao, Jiang
Querales-Flores, José D.
Fahy, Stephen B.
Savic, Ivana
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We present a first-principles-based model of electron-phonon scattering mechanisms and thermoelectric transport at the L and Σ valleys in 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 sizable 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.
Electron diffraction , Electron scattering , Electron-phonon interactions , IV-VI semiconductors , Landforms , Lead compounds , Phonon scattering , Thermoelectricity , Doping concentration , Electron phonon scattering , Energy differences , Longitudinal optical phonons , Scattering mechanisms , Thermoelectric performance , Thermoelectric transport , Transverse optical modes , Tellurium compounds
D'Souza, R., Cao, J., Querales-Flores, J. D., Fahy, S. B and Savic, I. (2020) 'Electron-phonon scattering and thermoelectric transport in p-type PbTe from first principles', Physical Review B, 102, 115204 (14pp). doi: 10.1103/PhysRevB.102.115204
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