Gutzwiller Variational Approximation to the Heavy-Fermion Ground State of the Periodic Anderson Model

A variational wave function for the Kondo-lattice limit of the periodic Anderson model is evaluated with a Gutzwiller approximation. We obtain a characteristic energy from this coherent wave function of the Kondo form but with a different exponent in the case of finite degeneracy. The effective mass and charge and spin susceptibilities are evaluated, and only in the case of large degeneracy and not too small hybridization strength is a heavy-Fermi-liquid state stable against magnetic order.