Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 20: Correlated Electrons - Poster Session

TT 20.42: Poster

Mittwoch, 28. März 2007, 14:00–17:45, Poster A

Coulomb correlations in Cu₂O and ZnO: Importance of both transition-metal U_dd and Oxygen U_pp — •Sven Binder, Hua Wu, Thomas Koethe, Stefan Klein, and Liu Hao Tjeng — II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln

Standard local density approximation (LDA) band structure calculations for Cu₂O and ZnO produce valence band spectra which show significant deviations from the experimentally observed spectra as obtained from photoemission. This is surprising since one may assume that Coulomb interactions can be well taken into account in a mean-field manner for closed shell systems. In an attempt to resolve this issue, we have performed LDA+U calculations. We have discovered that not only we have to include the Coulomb interaction in the 3d shell (U_dd) but also in the O 2p shell (U_pp). To justify this approach, we have set out to determine experimentally the values for U_dd and U_pp by performing L₃VV and KLL Auger spectroscopies for Cu₂O and ZnO.