Hopping perturbation treatment of the periodic Anderson model around the atomic limit - art. no. 245119

The periodic Anderson model with two strongly correlated subsystems of d an d f electrons and local on-site hybridization is investigated by considerin g the hopping of d electrons between lattice sites as perturbation. In zero order without the intersite transfer term, the system of correlated d and f electrons can be treated exactly. The delocalization of electrons and the corresponding renormalization of the one-particle Green's functions are an alyzed by using a special diagram technique from which the Dyson equations for the Green's functions are established. We discuss the physics of the de localized electrons in the simplest approximation corresponding to a Hubbar d I-like decoupling giving rise to eight different energy bands, which depe nd in a non-trivial way on the exact eigenvalues of the local model. These bands are discussed for the symmetrical case in which the energies of doubl y occupied d and f states are equal to each other.