Single Impurity Anderson Model versus Density Functional Theory for Describing Ce L_3 X-Ray Absorption Spectra of CeFe_2: Resolution of a Recent Controversy

摘要

We resolved a recent controversy on the structure of the Ce L_3 x-ray absorption spectra (XAS) of CeFe_2; i.e., which of the single impurity Anderson model (SIAM) and the first-principles band calculations based on the density-functional theory (DFT) describes more appropriately the Ce 4f states and their contribution to the Ce L_3 XAS? For this purpose, we examined the core-hole effect in Ce L_3 XAS as an application of our new method taking advantage of resonant x-ray emission spectroscopy. Our result clearly shows that the Ce L_3 XAS structure is caused by the mixed valence 4f character revealed by the core-hole potential effect as indicated by SIAM, but denies the possibility that the L_3 XAS structure is caused by the 5d band structure with a very small core-hole effect as predicted by band calculations based on DFT.