Dresden 2009 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 6: Postersession Correlated Electrons: (General) Theory, Low-Dimensional Systems, Kondo Physics, Heavy Fermions, Quantum-Critical Phenomena
TT 6.16: Poster
Monday, March 23, 2009, 13:00–16:45, P1A
Electronic properties of Fe, Mn, and Ni impurities in MgO thin films — T. Haupricht1, •Y.-Y. Chin1,2, R. Gierth1, J. Weinen1, S. G. Altendorf1, A. Hendricks1, Z. Hu1, J. Gegner1, H. Fujiwara1, D. Regesch1, H. H. Hsieh3, H.-J. Lin2, C. T. Chen2, and L. H. Tjeng1 — 1Institute of Physics II, University of Cologne, Germany — 2National Synchrotron Radiation Research Center, Hsinchu, Taiwan — 3Chung Cheng Institute of Technology, National Defense University, Taoyuan, Taiwan
Transition metal ions in MgO can serve as model systems for various (usually more complicated) dn systems in octahedral symmetry. Going from bulk crystals to impurity systems the core level and valence band photoemission (PES) and soft x-ray absorption (XAS) spectra can change significantly e.g. due to the absence of non-local screening effects [v. Veenendaal et al., PRL 70 (1993)]. Here, we present our core level and valence band PES and XAS data of Fe, Mn, and Ni impurities in MgO thin films grown on metal substrates in-situ by means of molecular beam epitaxy (MBE). Compared to the bulk compounds FeO, MnO, and NiO, remarkable differences are observed in the spectra. In order to understand these differences we have simulated the spectra using configuration interaction cluster calculations. Ab-initio oriented approaches such as LDA+DMFT are highly desired to obtain parameter free explanations.