Acoustic Deformation Potentials of n-type PbTe from First Principles*

There are conflicting reports in the literature regarding the strength of intravalley acoustic phonon scattering in PbTe [1,2], and the role it plays in PbTe's excellent thermoelectric properties. Efforts to calculate electron-phonon scattering in PbTe are further complicated due to the tendency of the standard density functional theory to produce an inverted band gap in materials with heavy elements when spin orbit coupling is taken into account [3]. In this work, we calculate the acoustic deformation potentials [4] in n-type PbTe from first principles using both the local density approximation and hybrid functionals. We find that the choice of the exchange correlation functional does not substantially affect the calculated deformation potential values once the physically correct representation of the conduction and valence band states near the band gap has been obtained. Our calculations show that the acoustic deformation potentials of n-type PbTe are much weaker than previously thought [1].

[1] Y. Ravich et al, Phys. Status Solidi (b) 43, 453 (1971)
[2] L. Ferreira, Phys. Rev. 37, A1601 (1956)
[3] K. Hummer et al, Phys. Rev. B 75, 195211 (2007)
[4] C. Herring and E. Vogt, Phys. Rev. 101, 944 (1956)