Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 83: [MA] Focussed Session "X-ray absorption spectra - state of the art of theory and experiment" (jointly with DS, HL, MM, O)

O 83.3: Topical Talk

Donnerstag, 17. März 2011, 16:15–16:45, HSZ 403

Theoretical description of X-ray absorption in correlated transition metal systems — •Hubert Ebert¹, Jan Minar¹, and Ondrej Sipr² — ¹Ludwig-Maximilians-Universität München, Department Chemie und Biochemie, Physikalische Chemie, Butenandtstraße 11, D-81377 München, Germany — ²Institute of Physics AS CR, Prague, Czech Republic

During the last years, great progress has been made in dealing with correlation effects in solids. Among the various theoretical approaches available now, the LSDA+DMFT (local spin density approximation + dynamical mean field theory) plays a prominent role, as it accounts for dynamical correlations when dealing with the ground state. We present a description of x-ray absorption spectra based on combining the LSDA+DMFT and the multiple scattering formalism. Working with a fully relativistic formulation, this approach gives access to a corresponding treatment of x-ray magnetic circular dichroism (XMCD). By applying the XMCD sum rules, we can demonstrate that the enhancement of orbital magnetism in ferromagnetic 3d-transition metals, which results from using the LSDA+DMFT formalism instead of plain LSDA, is indeed reflected by the XMCD spectra. Comparing the LSDA+DMFT-based XAS and XMCD spectra with experiment, however, some discrepancies remain that are ascribed to dynamical effects connected with the absorption process itself. To account for these effects we extended the sketched approach by including the presence of a core hole within the XAS and XMCD calculations using various schemes.