Many-body effects in magnetic circular dichroism at Ce L2,3 absorption edges in CeFe2

Magnetic circular dichroism (MCD) of the X-ray absorption spectroscopy (XAS) at the Cc L-2,L-3 edges in a typical mixed valence compound, CeFe2, is theoretically studied by using the impurity Anderson model combined with a cluster approach. We find that the hybridization of Ce 5d states with spin-polarized Fe 3d states is responsible for the differences between XAS and MCD, while the Coulomb interaction of a photo-excited 5d electrons plays a novel role, in addition to the many body effects yielding the two-peak structure of XAS. (C) 2003 Elsevier B.V. All rights reserved.