Mg/Ca doping ameliorates the thermoelectric properties of GeTe: Influence of electronic structure engineering

Abstract GeTe, though originally believed to be a poor thermoelectric material due to its inherent Ge vacancies has recently attracted the attention of the scientific community due to its tunable electronic structure. Herein, we study the electronic structure modifications of GeTe by means of doping it with Mg and Ca. Both Mg and Ca increases the band gap of GeTe and brings about valence band convergence decreasing the energy offset. The enhanced Seebeck co-efficient due to tuning of the electronic structure results in improved thermoelectric properties as predicted by the Boltzmann transport calculations. This strategy of doping could be very well extended to other dopants for improving the thermoelectric properties of GeTe.