Lattice thermal conductivity of filled skutterudites: An anharmonicity perspective

We report a phenomenological model to calculate the high-temperature lattice thermal conductivity of filled skutterudite antimonides. The model needs no phonon resonant scattering terms. Instead, we assume that umklapp processes dominate the high-temperature phonon scattering. In order to represent the anharmonicity introduced by the filling atom, we introduce a Gaussian term into the relaxation time of the umklapp process. The developed model agrees remarkably well with the experimental results of REfCo4Sb12 and REfFe4Sb12 (RE = Yb, Ba, and Ca) alloys. To further test the validity of our model, we calculate the lattice thermal conductivity of nanostructured or multifilled skutterudites. The calculation results are also in good agreement with experiment, increasing our confidence in the developed anharmonicity model. (C) 2014 AIP Publishing LLC.