Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 2: Magnetic Thin Films I
MA 2.1: Vortrag
Montag, 27. März 2006, 10:15–10:30, HSZ 03
Measuring the kernel of time-dependent density functional theory with X-ray absorption spectroscopy of 3d transition metals — •H. Wende1, A. Scherz2, E.K.U. Gross1, H. Appel1, C. Sorg1, K. Baberschke1, and K. Burke3 — 1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin-Dahlem, Germany. — 2SSRL, 2575 Sand Hill Road, Menlo Park, California 94025, USA — 3Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Rd, Piscataway, NJ 08854, USA
We showed that the induced magnetic moments in ultrathin films of the light 3d elements Ti, V and Cr at the interface to Fe cannot be determined by the XMCD sum rule analysis at the L2,3 edges. The reasons are correlation effects which result in the deviation of the intensity ratio (branching ratio) from its statistical value. Therefore, we established a double-pole approximation within time-dependent density functional theory to investigate these effects in detail. A (2×2) matrix of the matrix elements of the unknown exchange correlation kernel is used to describe the shift of the two transitions (diagonal) and the change of the branching ratio (off-diagonal elements). We experimentally measure the branching ratios and level splittings for these films, and deduce these matrix elements. It turns out that off-diagonal matrix elements are much smaller (factor 5) than the diagonal ones which demonstrates that the change of the branching ratio for the light 3d elements is simply due to transition repulsion, as the two transitions near one another (reduced spin-orbit splitting). Supported by BMBF (05 KS4 KEB 5).
[1] A. Scherz et al., Phys. Rev. Lett. in print