Regensburg 1998 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 21: Postersitzung III: Spin-Peierls-Systeme, Metall-Isolator-Übergang, Lokalisierung; SL: Theorie; Quantenflüssigkeiten und -kristalle; Amorphe Materialien, Tunnelsysteme; Borcarbide, Fullerene, konventionelle SL; SL dünner Filme; Experimentiertechniken
TT 21.44: Poster
Donnerstag, 26. März 1998, 15:00–18:30, D
Static and dynamic properties of the 1-Band Hubbard Model with longer-ranged hoppings — •C. Gröber, G. Hildebrand, H. G. Evertz, E. Arrigoni, R. Eder, and W. Hanke — Institut für Theoretische Physik, Am Hubland, D-97074 Würzburg
On the basis of Quantum-Monte-Carlo simulations in connection with Maximum-Entropy techniques for the spectral weight A (k→,ω) and for the two-particle spin- and charge-response χs,c (q→,ω) we investigate the influence of longer-ranged hoppings on the static and dynamic properties of the Hubbard model. In accordance with experiment we find the Fermi surface of the model closing around the point (π, π) when a second-nearest neighbor hopping of t′/t=−0.2 is introduced. This situation does not change with an additional third-nearest neighbor hopping of t″/t=0.15. The influence of these longer-ranged hoppings is investigated for the parameter sets with a hopping of t′ alone and with hoppings t′ and t″ together, for several temperatures in the half-filled case and for several dopings at inverse temperature β t=3 in the under-doped situation.