First principles simulations of electron-phonon coupling and thermoelectric transport in PbTe

Date

Oct 10, 2024

Time

1:00 PM - 3:00 PM

Speaker

Ivana Savic

Affiliation

Department of Physics, King's College London

Series

TUD nanoSeminar

Language

en

Main Topic

Physik

Other Topics

Physik

Host

Arezoo Dianat

Description

I will describe our recent development of a first principles thermoelectric transport model based on the Boltzmann transport theory and its application to the classic high-performing thermoelectric material PbTe [1,2]. Unlike nowadays standard methods which calculate electron-phonon matrix elements in the entire Brillouin zone using density functional perturbation theory and Wannier/Fourier interpolation [3], our model makes use of deformation potential theory, which dramatically reduces the number of electron-phonon matrix elements that need to be computed. This development is important for narrow-gap semiconductors such as PbTe, where the band structures are often inaccurately captured by density functional theory, and the effects of electron correlations on electron-phonon matrix elements might be necessary to include [4]. 
 
 Regarding the physical effects, I will show that soft transverse optical modes are the key to the high thermoelectric figure of merit of PbTe: they preserve its high electronic conductivity while suppressing the lattice thermal conductivity [1]. I will also present our recently developed understanding of the role of intervalley scattering in establishing the high thermoelectric figure of merit of p-type PbTe [2,5].
 
 [1] J. Cao, J. D. Querales-Flores, A. R. Murphy, S. Fahy, and I. Savic, Phys. Rev. B, 98, 205202 (2018)
 [2] R. D'Souza, J. Cao, J. D. Querales-Flores, S. Fahy, and I. Savic, Phys. Rev. B 102, 115204 (2020)
 [3] S. Ponce, E. R. Margine, C. Verdi, and F. Giustino, Comput. Phys. Commun. 209, 116 (2016)
 [4] A. R. Murphy, F. Murphy-Armando, S. Fahy, and I. Savic, Phys. Rev. B 98, 085201 (2018)
 [5] R. D'Souza, J. D. Querales-Flores, J. Cao, S. Fahy, and I. Savic, ACS Appl. Energy Mater. 5, 7260 (2022)

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Last modified: Oct 11, 2024, 7:41:04 AM