Dresden 2009 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 38: Correlated Electrons: Low-dimensional Systems - Models 1
TT 38.10: Vortrag
Donnerstag, 26. März 2009, 12:15–12:30, HSZ 301
Momentum dependence of the spin-susceptibility in two dimensions: nonanalytic corrections in the Cooper channel — Stefano Chesi1, •Robert Zak1, Pascal Simon1,2,3, and Daniel Loss1 — 1Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland — 2Laboratoire de Physique et Modelisation des Milieux Condenses, CNRS and Universite Joseph Fourier, BP 166, 38042 Grenoble, France — 3Laboratoire de Physique des Solides, CNRS UMR-8502 Universite Paris Sud, 91405 Orsay Cedex, France
We consider the effect of rescattering of pairs of quasiparticles in the Cooper channel resulting in the strong renormalization of second order corrections to the spin susceptibility in a two-dimensional electron system. We use the Fourier expansion of the scattering potential in the vicinity of the Fermi surface to find that each harmonic becomes renormalized independently. Since some of those harmonics are negative, the slope of the spin susceptibility is bound to be negative at small momenta, in contrast to the lowest order perturbation theory result, which predicts a positive slope. We present in detail an effective method to calculate diagrammatically corrections to the spin susceptibility to infinite order.