Dynamical cluster approximation for study of non-local correlations in the periodic anderson model

The single particle excitation spectrum of the periodic Anderson model in two dimensions is calculated by using the dynamical cluster approximation (DCA). The DCA method restores the short ranged inter-site correlations which are neglected in the dynamical mean field approximation. For the half filling model the resonance peak at the Fermi level is suppressed due to the anti-feromagnetic RKKY-like interaction. When the filling of the conduction electron band is small, there is a sharp coherence peak. It can be explained that the effect of the RKKY-like interaction is weaker than that for the half filling model. For the intermediate filling model the intensity of the coherence peak becomes very small. (author)