Dynamical conductivity of heavy fermion systems: effect of impurity scattering

The influence of impurity scattering on a heavy fermion system is studied within a mean-field approximation of the Anderson Hamiltonian and using a coherent potential approximation for the impurity scattering. Two types of scattering mechanisms are investigated: missingf-ions and potential scatterring centers. The dynamical conductivity shows a nearow peak at low frequencies scaling with the effective mass of the heavy quasi-particles together with a peak at finite frequencies due to interband transitions. These features are also found in experimental results on heavy fermion systems.