Regensburg 2004 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 26: Korrelierte Elektronen: Theorie II

TT 26.7: Vortrag

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

Electron-spin Vertex in the Two-dimensional One-band Hubbard Model — •Zhongbing Huang, Werner Hanke, and Enrico Arrigoni — Institut für Theoretische Physik, Universität Würzburg, am Hubland, 97074 Würzburg, Germany

Using Quantum Monte Carlo techniques, we study the renormalization of the electron-spin (el-sp) interaction or vertex due to Coulomb correlations in a two-dimensional one-band Hubbard model with spin-fluctuation momentum transfer q=(π,π). In the physically relevant strong-correlation regime, we find that the renormalized el-sp vertex decreases monotonically and rather dramatically with increasing doping from the underdoped to the overdoped region. In the underdoped region the spin susceptibility increases very quickly with decreasing temperature, leading to a substantial increase of the effective pairing interaction. In the overdoped case, the temperature dependence of the effective pairing interaction is rather weak. Our findings imply that antiferromagnetic spin fluctuations play an important role in the transport and superconducting properties of the underdoped high-temperature superconductors. This will further be substantiated with similar calculations for the electron-phonon vertex.

11:15 Pause