Ab initio study of thermoelectric transport properties of pure and doped quaternary compounds (original) (raw)

Recent experiments on thermoelectric characterization of doped quaternary compounds of sattanite or kesterite-type Cu 2 ZnSnSe 4 , Cu 2 ZnSnS 4 , and Cu 2 CdSnSe 4 , show promise for their use as bulk thermoelectrics. In this paper we present and discuss the energetic, electronic, and transport properties of several tetrahedrally bonded quaternary compounds Cu 2 QSnX 4 , where Q = Zn, Cd; X =S,Se,Te and their alloyed/doped structures, Cu doped at Q sites and M doped ͑M =Al,Ga,In͒ at Sn sites, for elucidating their thermoelectric performance. In our calculations, using density-functional theory and Boltzmann transport equations, we determine Seebeck coefficients, conductivities, power factors, a simple measure "maximum" ZT for each compound at experimentally amenable doping levels. Based on the electronic-structure and transport property calculations, we conclude that the base compounds and several doped compounds show similar potential as thermoelectric materials to the experimentally characterized one.