First-principles prediction the effect of lattice deformation on thermoelectric properties of CuGaTe2

Under several strains, the band structures of CuGaTe2 are calculated with modified Becke-Johnson potential via full-potential all-electron linearized augmented plane wave method. It is found that the uppermost light and heavy valence bands converge at −0.5% compressive strain. Based on the electronic structure calculations, we investigate their thermoelectric properties by semi-classical Boltzmann transport theory. The results suggest that CuGaTe2 at −0.5% compressive strain displays the highest value of Seebeck coefficient. The in-plane and out-of-plane power factors over relaxation time can be increased under compressive strain. The optimal p-type doping concentrations are estimated based on the predicted maximum values of power factors.