Influence of electron-phonon interaction on the lattice thermal conductivity ofCo1−xNixSb3

We have investigated the effect of electron-phonon scattering in a series of n-type nickel-doped ${\mathrm{CoSb}}_3$ skutterudite materials. Samples were polycrystalline of the form ${\mathrm{Co}}_{1-x}{\mathrm{Ni}}_x{\mathrm{Sb}}_3$ with $x=0,$ 0.001, 0.003, 0.005, 0.0075, and 0.01. The lattice thermal conductivity decreases dramatically with increasing Ni doping for $x<~\mathrm{0.003.}$ For higher Ni concentration the reduction of the lattice thermal conductivity saturates. Our theoretical analysis indicates that this reduction of the lattice thermal conductivity cannot be explained solely by point-defect scattering of the phonons. Rather, we can fit the lattice thermal conductivity of Ni-doped ${\mathrm{CoSb}}_3$ by introducing an electron-phonon scattering mechanism, and this demonstrates that the electron-phonon interaction can play an important role in the reduction of the heat conduction in n-type skutterudites.