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TT: Tiefe Temperaturen

TT 15: Postersitzung II: Elektronische Eigenschaften (1-12), Josephson-Kontakte (13-27), Heavy Fermions (28-40), Theorie HTSL (41-48), M-I-Überg
änge, Korrelierte Systeme (49-79)

TT 15.69: Poster

Mittwoch, 24. März 1999, 14:30–18:00, Foy

Detailed Comparison of Photoemission Results from 1-Band t−t′−U Hubbard Models and High-T_c-Superconductors — •Carsten Gröber, Hans Gerd Evertz, and Werner Hanke — Institut fuer Theoretische Physik, Universität Würzburg, Am Hubland 97074, Germany

On the basis of Quantum-Monte-Carlo simulations of the two-dimensional t−t′−U Hubbard-model with U=8   t, t′=−0.2   t and t=0.45   eV we find that photoemission results on Sr₂CuO₂Cl₂ and Bi₂Sr₂CaCu₂O_8+δ are reproduced in excellent agreement with experiment in the whole doping range from half-filled to over-doped. Both the dispersion and the width of the bands are reproduced as well as the broad peaks at (π,0) in the under-doped regime which sharpen up again in the over-doped region. For the first time the underlying peak width (equivalent to the quasi-particle scattering rate) is derived from high quality Quantum-Monte-Carlo data. Our results suggest that the unique doping dependence of the spin response identifies antiferromagnetic correlations as the driving mechanism behind all the (π,0)-features (pseudogap, broad peaks) in the under-doped regime.