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TT: Tiefe Temperaturen
TT 24: Postersitzung III: Korrelierte Elektronen, ”Orbital Physics”
TT 24.23: Poster
Wednesday, March 10, 2004, 14:30–19:00, Poster A
Electronic structure, magnetism, and superconductivity in pseudo-ladder compounds — •S.-L. Drechsler1, H. Rosner1, N.M. Plakida2, A. Vladimirov3, H. Eschrig1, and M. Knupfer1 — 1IFW-Dresden, P.O. Box 270116, 01171 Dresden, Germany — 2MPI-CPfS Dresden, Germany — 3J. Inst. f. Nuclear Res., Dubna, Russia
The electronic structure of ACu2O3 compounds [A=Ca,Mg] has been calculated within the local density approximation and compared with x-ray absorption spectroscopy and magnetic neutron scattering data [1]. Both compounds deviate markedly from the usual pdσ cuprate picture. Significant interlayer exchange in the stacking c-direction is found to be responsible for the missing spin gap (generic for ideal two-leg ladders) and the finite Néel-temperature. Hence, they can be modelled as weakly coupled anisotropic Heisenberg (Hubbard) bi-layers. Within a derived effective t-J-model in mean-field approximation nodeless superconductivity below 50 K is predicted for Ca0.88Na0.12Cu2O3 (optimal hole doping).
[1]V. Kiryukhin et al., PRB 64, 1444418 (2001).