Abstract
The theoretical description of photoemission spectra of transition metals was greatly improved recently by accounting for the correlations between the electrons within the local spin-density approximation (LSDA) plus dynamical mean-field theory (DMFT). We assess the improvement of the LSDA+DMFT over the plain LSDA in x-ray absorption spectroscopy, which—unlike the photoemission spectroscopy—is probing unocccupied electronic states. By investigating the edge x-ray absorption near-edge structure (XANES) and x-ray magnetic circular dichroism (XMCD) of Fe, Co, and Ni, we find that the LSDA+DMFT improves the LSDA results, in particular concerning the asymmetry of the white line. Differences with respect to the experiment, nevertheless, remain—particularly concerning the ratio of the intensities of the and peaks. The changes in the XMCD peak intensities invoked by the use of the LSDA+DMFT are a consequence of the improved description of the orbital polarization and are consistent with the XMCD sum rules. Accounting for the core hole within the final-state approximation does not generally improve the results. This indicates that to get more accurate edge XANES and XMCD spectra, one has to treat the core hole beyond the final-state approximation.
- Received 17 May 2011
DOI:https://doi.org/10.1103/PhysRevB.84.115102
©2011 American Physical Society