Abstract
The conversion of waste heat into electrical energy by spin Seebeck effect (SSE) can be a proficient alternative of traditional thermoelectrics. For this purpose, most efficient materials are required. In this article, we report Cs2WX6 (X = Cl, Br) ferromagnetic materials for possible SSE on the basis of results of first principles calculations combined by density functional and classical Boltzmann transport theories. The synthesis possibility of both the compounds is verified from negative values of formation energy, while the cubic phase stability is evaluated through calculated values of tolerance factor. The ductile elastic nature is confirmed from Cauchy pressure and Pugh's condition. The lattice thermal conductivity calculated through Slack's equation is observed to decrease with rise in temperature. Electronically, both Cs2WX6 compounds are predicted as half metallic through density of states, band structure and integral values of magnetic moments (2 mu(B)). Moreover, from spin-dependent thermoelectric properties, large values Seebeck coefficients and figure of merit are observed in spin-down states in comparison of spin-up channel. The spin-dependent thermoelectric parameters along with half metallic character make Cs2WX6 compounds suitable for spin Seebeck effect.