Volume 71, Number 6, September 2005
|Page(s)||959 - 965|
|Section||Condensed matter: electronic structure, electrical, magnetic, and optical properties|
|Published online||17 August 2005|
Role of vertex corrections in the spin-fluctuation–mediated pairing mechanism
Institut für Theoretische Physik und Astrophysik, Universität Würzburg am Hubland, 97074 Würzburg, Germany
2 Department of Physics, Hubei University - Wuhan 430062, PRC
3 Institut für Theoretische Physik, Computational Physics, Technische Universität Graz Petersgasse 16, A-8010 Graz, Austria
Accepted: 15 July 2005
We study numerically and partly diagrammatically the renormalization of the electron-spin interaction or vertex in a two-dimensional one-band Hubbard model with spin-fluctuation momentum transfer . We find that the renormalized electron-spin vertex decreases quite generally with decreasing temperature at all doping densities. As a combination of two concurring effects, i.e. the decrease of the vertex and the increase of the spin susceptibility, the effective pairing interaction increases with lowering temperature in the intermediate-correlation regime, but flattens off in the strong-correlation regime. Our findings indicate that in the high- cuprates the pairing mediated by antiferromagnetic spin fluctuations is substantially reduced due to vertex corrections.
PACS: 71.27.+a – Strongly correlated electron systems; heavy fermions / 71.10.Fd – Lattice fermion models (Hubbard model, etc.)
© EDP Sciences, 2005
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