Coexistence of antiferromagnetism and superconductivity in the Anderson lattice

We study the interplay between anti ferromagnetism and superconductivity in a generalized infinite-U Anderson lattice, where both superconductivity and antiferromagnetic order are introduced phenomenologically in mean field theory. In a certain regime, a quantum phase transition is found which is characterized by an abrupt expulsion of magnetic order by d-wave superconductivity, as externally applied pressure increases. This transition takes place when the d-wave superconducting critical temperature, T-c, intercepts the magnetic critical temperature, T-m, under increasing pressure. Calculations of the quasiparticle bands and density of states in the ordered phases are presented. We calculate the optical conductivity sigma (omega) in the clean limit. It is shown that, when the temperature drops below T-m, a double peak structure develops in sigma (omega).