Interpolative solution for the periodic Anderson model of mixed-valence compounds

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Abstract
A general solution for the periodic Anderson model of mixed-valence compounds is presented. The method uses Green-function techniques and is based on the introduction of an appropriate self-energy by interpolating between two extreme limits: Small intrasite Coulomb interaction and small hopping integral between the d and f levels of the same site. The method has been checked for a simple model of an impurity, and the conclusion is that its accuracy for calculating the density of states is better than 10%. We have applied the general method to a one-dimensional chain, with two electrons per site, a degeneracy of spin 1/2 for the f level and zero temperature, and have calculated its electronic density of states. We give results for the electronic bands near the fundamental gap and the integrated density of states for different parameters, and show that the paramagnetic phase is always insulating in agreement with a kind of Luttinger’s sum rule.