Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 26: Electron Theory
MA 26.9: Vortrag
Donnerstag, 30. März 2006, 12:15–12:30, HSZ 401
Electronic structure of REAuMg and REAgMg (RE = Eu, Gd, Yb) — •Jan Gegner1, T.C. Koethe1, Hua Wu1, H. Hartmann1, T. Lorenz1, T. Fickenscher2, R. Pöttgen2, and L.H. Tjeng1 — 1II. Physikalisches Institut der Universität zu Köln, Germany — 2Institut für Anorganische und Analytische Chemie,Westfälische Wilhelms-Universität Münster, Germany
We have investigated the electronic structure of the equiatomic EuAuMg, GdAuMg, YbAuMg and GdAgMg intermetallics using x-ray photoelectron spectroscopy. The spectra revealed that the Yb and Eu are divalent while the Gd is trivalent. The spectral weight in the vicinity of the Fermi level is in all cases dominated by the mix of Mg s, Au/Ag sp and RE spd bands, and not by the RE 4f. We also found that the Au and Ag d bands are extraordinarily narrow, as if the noble metal atoms were impurities submerged in a low density sp metal host. The experimental results were compared with band structure calculations, and we found good agreement provided that the spin-orbit interaction in the Au an Ag d bands is included and correlation effects in the open 4f shells are accounted for using the LDA+U scheme. Nevertheless, limitations of such mean-field scheme to explain excitation spectra are also evident.