Influence of d-wave order parameter fluctuations on spill fluctuations in underdoped high-T-c cuprates

Dahm T, Manske D, Tewordt L. Influence of d-wave order parameter fluctuations on spill fluctuations in underdoped high-T-c cuprates. EPL (Europhysics Letters). 1997;39(2):201-206.We consider the effect of fluctuations of the superconducting d(x2-y2)-wave gap above T-c for the 2D Hubbard model. The order parameter fluctuations (OPFL) lead to a decrease of T-c and to a suppression of the dynamical spin susceptibility below a crossover temperature T* which can be much larger than T-c. The temperature T* increases while T-c decreases with increasing strength of OPFL, or decreasing doping. The resulting neutron scattering intensity and NMR relaxation rates decrease below T* for decreasing T. This agrees qualitatively with the observed spin gap behavior in the underdoped high-T-c cuprates