The single particle excitation spectrum of the periodic Anderson model in two dimensions is calculated by using the dynamical cluster approximation (DC A). The DC A method restores the short ranged inter-site correlations which are neglected in the dynamical mean field approximation. For the half filling model the resoance 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 explaind 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.
- Dynamical cluster approximation
- Non-crossing approximation
- Periodic anderson model