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TT: Tiefe Temperaturen

TT 26: Korrelierte Elektronen: Theorie II

TT 26.3: Vortrag

Donnerstag, 11. März 2004, 10:00–10:15, H18

Electron-phonon interaction in the t-J model — •Oliver Rösch and Olle Gunnarsson — Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart

Starting from the three-band model of a CuO₂ layer we derive a t−J model with electron-phonon interaction taking into account the modulation of both hopping and Coulomb integrals by phonons. The former is found to be dominant, but the modulation of the Coulomb integrals cannot be neglected.

The model is studied on finite clusters using exact diagonalization. It explains the anomalous softening of the half-breathing mode upon doping and a weaker renormalization of the breathing mode as observed experimentally in many cuprates. The coupling to other modes is not strong in this model.