Lattice thermal conductivity and spectral phonon scattering in FeVSb-based half-Heusler compounds

Alloying and grain refinement have been conducted to reduce the lattice thermal conductivity of FeVSb-based half-Heusler compounds. And the effects of point defect and boundary on phonon scattering are analyzed using the Callaway model. Point defect scattering and boundary scattering, respectively, cut out the high-frequency and low-frequency phonons. Consequently, most of the heat (similar to 70%) is carried by phonons with mean free path (mfp) in the range of 1-80 nm and 0.6-30 nm at Debye temperature and 650K, respectively, indicating that further reduction in lattice thermal conductivity should enhance the scattering of phonons with these characteristic mfp. Copyright (C) EPLA, 2013