Comment on “Electronic thermal conductivity and the Wiedemann-Franz law for unconventional superconductors”

Abstract

A different treatment of the electronic contribution to the in-plane thermal conductivity of high-${T}_{c}$ superconductors than in Graf et al. [Phys. Rev. B 53, 15 147 (1996)] leads to a nonconventional ${T}^{2}$ dependence of the electron-impurity contribution in contrast to the predicted linear dependence of Graf et al. In fact, taking into account both electron-impurity-phonon scattering leads to a nontrivial ${T}^{\ensuremath{\beta}}$ dependence as found experimentally in various high-${T}_{c}$ materials, where $\ensuremath{\beta}$ results from different $T$-dependent contributions as well as the values of the impurity fraction in the sample $N$ and the in-plane transport electron-phonon coupling constant of the material ${\ensuremath{\lambda}}_{\mathrm{ab}}.$