First principles thermoelectric performance calculations of TiN, ZnS, and Ag2Se at low temperatures

Abstract

In this work ab initio computations are used to explore the low temperature, thermoelectric performance of pure, single crystal TiN (Fm3‾m), ZnS (P63mc) and Ag2Se (P212121). Complimenting ab initio theory, the quasi harmonic approximation and solutions to the Boltzmann transport equation are also used to solve for the underlying structural and elastic properties, to include bulk and shear modulus, electronic band structure, phonon dispersion, heat capacity, thermal conductivity, and figure of merit. Where applicable, the results agree well with those of previously published works, and among other findings, confirm the relatively large figure of merit specifically attributable to Ag2Se. In addition to providing a viable computational approach to the solution of these aformentioned properties, this work is also intended to serve as a baseline from which additional alloy derivatives may be explored.