Theoretical study of thermoelectric properties of n-type doped Mg2Si0.4Sn0.6 solid solutions

Abstract

In this work, a systematic theoretical investigation of thermoelectric properties of n-type doped [GRAPHICS] solid solutions with [GRAPHICS] is presented in the temperature range [GRAPHICS] K. Electronic transport properties ( [GRAPHICS] , S, and [GRAPHICS] ) are calculated using the nearly-free-electron approximation and the Fermi-Dirac statistics. Thermal transport properties including contributions from carriers ( [GRAPHICS] ), electron-hole pairs ( [GRAPHICS] ) and phonons ( [GRAPHICS] ) computed using the Wiedemann-Franz law, Price's theory and Srivastava's scheme, respectively. in a very good agreement with available experimental measurements, among with [GRAPHICS] samples, the highest value for thermoelectric figure of merit ZT is found to be 1.41 at 800K for [GRAPHICS] sample owing to its highest electrical conductivity and the lowest lattice thermal conductivity values. Additionally, by theoretically considering the doping levels as [GRAPHICS] , we suggest that at 800K ZT goes up by 30% for [GRAPHICS] sample with the value of [GRAPHICS] compared to [GRAPHICS] sample due to increment in the electrical conductivity and additional mass defect effects to the phonon thermal conductivity.