VARIATIONAL THEORY OF CORRELATED FERMI-LIQUID STATE IN THE KONDO LATTICE MODEL

A variational wave function is constructed and studied for the spin-compensated Fermi-liquid-type ground state in the Kondo lattice model. The spins of the localized f-electrons are compensated by overlapping conduction-electron clouds. In accordance with Luttinger's theorem, the volume enclosed by the Fermi surface corresponds to the total number of electrons, i.e., it includes the f-electrons as well as the conduction electrons. An approximate analytic treatment of the correlated heavy Fermi liquid is given by using the Gutzwiller approximation.