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TT: Tiefe Temperaturen

TT 3: Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter I

TT 3.9: Talk

Monday, March 24, 2003, 11:30–11:45, HSZ301

The LSDA+U band structure of undoped cuprates revisted — •K. Koepernik, H. Eschrig, and I. Chaplygin — IFW Dresden, P.O.B. 27 0016, D-01171 Dresden, Germany

The electronic structure of undoped cuprates is reanalyzed with the help of the LDA+U approach of density functional theory. It is found that in-plane oxygen orbitals forming π-bonds with copper are in energetic concurrence to those forming the Zhang-Rice singlet. The corresponding bands display a surprisingly large c-axis dispersion due to hybridization with unoccupied cation d-states in the adjacent layers. This must have relevance for the c-axis magnetic couplings as well as for the so-called bilayer splitting. In view of this situation, the Emery model is incomplete for the description of magnetism of undoped cuprates.