Regensburg 2000 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
TT: Tiefe Temperaturen
TT 10: Supraleitung: Theorie
TT 10.5: Vortrag
Dienstag, 28. März 2000, 11:45–12:00, H19
Antiferromagnetic Spin Correlations, Pseudogaps and Superconductivity in the Hubbard Model — •Thomas Maier1, Mark Jarrell2, Thomas Pruschke1, and Joachim Keller1 — 1Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany — 2Department of Physics, University of Cincinnati, Cincinnati, OH 45221
Using the Hubbard Model we performed calculations within the recently developed Dynamical Cluster Approximation (DCA). The DCA technique includes short ranged correlations by mapping the lattice problem onto a self-consistently embedded periodic cluster. In the paramagnetic state at moderate doping we find that the antiferromagnetic (AF) spin fluctuations drive the system to a pseudogap phase with d-wave symmetry. With increasing doping the AF spin fluctuations are suppressed and the system shows a crossover to a Fermi liquid consistent with experimental observations. As the temperature decreases we observe a transition to a superconducting state in doped systems. The order parameter has d-wave symmetry and the highest transition temperature Tc is obtained for 18% doping. In underdoped and overdoped systems superconductivity gets suppressed and Tc drops rapidly in agreement with experiments on the cuprates.