Effect of non-local correlations in the periodic Anderson model studied by the dynamical cluster approximation

The single particle excitation spectrum of the periodic Anderson model for the half filling case 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 (DMFA). A comparison between the results by DCA and DMFA shows that the resonance peak in low energies is suppressed due to the non-local correlations. (C) 2002 Elsevier Science B.V. All rights reserved.