Superconducting Gap Nodal Surface and Fermi Surface: their partial overlap in cuprates

Abstract

Electron correlation in cuprates leads to a global constraint ${\sum }_{\mathbf{k}}{\Delta }_{\mathbf{k}}=0$ on the gap function ${\Delta }_{\mathbf{k}}$ resulting in a gap nodal surface. We give physical arguments supported by numerical results and discuss some experimental results to argue that correlations also lead to a local constraint on charge fluctuations in $\mathbf{k}$-space close to the Fermi surface, which may result in a substantial overlap of the Fermi surface with the gap nodal surface.

RevTeX 3.0, 4 Pages, 6 PostScript Figures.