Thermal transport properties of some iron based semiconductors from first principles

We have performed first-principles calculations on the phonon transport properties of iron based semiconductors (FeX2 X=S, Se, Te, and Sb) in the marcasite structure. The calculations have been carried out using density functional theory and Peierls-Boltzmann transport methods. Phonon dispersions, group velocities, mode Grüneisen parameters, anharmonic scattering rates and lattice thermal conductivity are calculated and the results are discussed with available experiments and other calculations. Possible anharmonic effects are also investigated in detail. We have found significant contributions from low frequency optic mode region (hybridized with acoustic modes) to the lattice thermal conductivity for all materials investigated. The large experimental decrease of thermal conductivity of FeS2 and FeSb2 by nanostructuring is also verified by our calculations for room temperatures and above.