Electron-phonon coupling and electronic thermoelectric properties of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>n</mml:mi></mml:math> -type PbTe driven near the soft-mode phase transition via lattice expansion

IV-VI materials are some of the most efficient bulk thermoelectric due to their proximity soft-mode phase transitions, which leads low lattice thermal conductivity. It has been shown that conductivity PbTe can be considerably reduced by bringing closer transition e.g. via expansion. However, effect soft phonon modes on electronic properties such system remains unknown. Using first principles calculations, we show zone center transverse optical phonons do not deteriorate driven expansion external stress, and thus enhance figure merit. We find deformation potentials change very weakly as increases, but population scattering space increase. Nevertheless, between states near band edge relatively weak even transition.