Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 33: Symposium: High-Temperature Superconductivity
TT 33.4: Vortrag
Donnerstag, 28. Februar 2008, 15:30–15:55, H 0104
Momentum-resolved electron-phonon coupling and self-energy effects in YBa2Cu3O7: an LDA study — •Rolf Heid1, Klaus-Peter Bohnen1, Roland Zeyher2, and Dirk Manske2 — 1Forschungszentrum Karlsruhe, Institut für Festkörperphysik — 2Max-Planck-Institut für Festkörperforschung, Stuttgart
The observation of kinks in the electronic dispersion of high-Tc cuprates by angle resolved photoemission experiments has revived the discussion about the importance of electron-phonon interaction in the cuprates. Here we determine the effect of the electron-phonon coupling on the electronic self-energy in the normal state within the local-density approximation. Using a realistic phonon spectrum we determine the momentum and frequency dependence of α2F(k,ω) in YBa2Cu3O7 for the bonding, antibonding, and chain band. We find that the maximum in the real part of the self-energy at low frequencies is about a factor 5 too small compared to the experiment. The renormalization factor Z(k,ω), which determines the change in the slope of the electronic dispersion due to the interaction, varies smoothly as a function of frequency and momentum. These findings show that, at least within the LDA, phonons cannot produce well-pronounced kinks in YBa2Cu3O7.