Electrical resistivity of heavy-fermion systems with nonmagnetic impurities.

Abstract

We study nonmagnetic impurities, i.e., ``Kondo holes,'' in the periodic Anderson model in infinite dimensions d=\ensuremath{\infty}. We use standard perturbation theory up to second order in the Coulomb correlation U for the f electrons together with the coherent potential approximation to treat the Kondo holes. Choosing the parameters so that the Fermi energy of the pure system (without impurities) lies within the hybridization gap, our theory describes the influence of ``Kondo holes'' on the transport properties of Kondo insulators like ${\mathrm{Ce}}_{3}$${\mathrm{Bi}}_{4}$${\mathrm{Pt}}_{3}$. For other parameters (total number of electrons per site) the dependence of the resistivity on nonmagnetic impurities in metallic heavy-fermion systems (such as ${\mathrm{CeAl}}_{3}$, ${\mathrm{CeCu}}_{6}$) is accounted for. For both situations we calculate the density of states and the electrical resistivity as a function of temperature for different impurity concentrations. Qualitatively we obtain the correct behavior of the electrical resistivity as a function of temperature, Kondo hole concentration, and the filling of the f electrons and the band electrons. \textcopyright{} 1996 The American Physical Society.