Many-body effects in x-ray absorption and magnetic circular dichroism spectra within the LSDA+DMFT framework

Abstract

The theoretical description of photoemission spectra of transition metals was greatly improved recently by accounting for the correlations between the d 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 L2,3-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 L3 white line. Differences with respect to the experiment, nevertheless, remain --- particularly concerning the ratio of the intensities of the L3 and L2 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 L2,3-edge XANES and XMCD spectra, one has to treat the core hole beyond the final state approximation.

arXiv comment4 figures, 1 table, 8 pages

References in corpus (13)

• Electronic Structure Calculations with Dynamical Mean-Field Theory: A Spectral Density Functional Approach
• Correlated metals and the LDA+U method
• Anisotropy and Magnetism in the LSDA+U Method
• Theory of quasiparticle spectra for Fe, Co, and Ni: bulk and surface
• Multiple scattering formalism for correlated systems: A KKR+DMFT approach
• Importance of Correlation Effects on Magnetic Anisotropy in Fe and Ni
• About the strength of correlation effects in the electronic structure of iron
• Orbital magnetism in transition-metal systems: The role of local correlation effects
• Orbital Polarization in Itinerant Magnets
• Quantitative determination of spin-dependent quasiparticle lifetimes and electronic correlations in hcp cobalt
• Electronic structure and effects of dynamical electron correlation in ferromagnetic bcc-Fe, fcc-Ni and antiferromagnetic NiO
• Observation and theoretical description of the pure Fano-effect in the valence-band photo-emission of ferromagnets
• Effects of electronic correlation on X-Ray absorption and dichroic spectra at L${}_{2,3}$ edge

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