First-principles study of thermal transport in FeSB[subscript 2]

Abstract

We study the thermal transport properties of FeSb[subscript 2], a promising thermoelectric material for cooling applications at cryogenic temperatures. A first-principles formalism based on density functional theory and ab initio lattice dynamics is applied. We calculate the electronic structure, the phonon dispersion relation, the bulk thermal expansion coefficient, and the thermal conductivity of FeSb[subscript 2] and compare them with other calculations and experiments. Our calculation is found insufficient to fully explain the temperature dependence of the lattice thermal conductivity of FeSb[subscript 2], suggesting new scattering mechanisms in this strongly correlated system. The mean free path distribution of different phonon modes is also calculated, which may provide valuable guidance in designing nanostructures for reducing the thermal conductivity of FeSb[subscript 2] and improving the thermoelectric figure of merit zT.