Ab initio lattice thermal conductivity in pure and doped Half-Heusler thermoelectric materials
Abstract
Half-Heusler phases are promising intermetallics for applications in thermo-electric generators. Optimization of their thermal transport properties is essential to improve their overall conversion efficiency. Our goal is to perform a theoretical evaluation of thermal transport properties directly from first-principles calcula-tions for various pure and doped half-Heusler compounds. The electronic struc-tures are modeled in the framework of the density functional theory (DFT). The ab initio thermal properties are deduced from harmonic and anharmonic interatomic force constants calculations using finite size displacements method. Many-body perturbation theory is used for calculating the phonon-phonon interactions which yields the lifetime of phonons as function of momentum and band index. Finally, thanks to a direct solution to the phonons Boltzmann transport equation we com-puted the ab initio thermal conductivities, which are found in good agreement with the experimental data.
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