Abstract
In order to explore how superconductivity arises when charge fluctuations and spin fluctuations coexist, we have obtained a phase diagram against the off-site repulsion and band filling for the extended, repulsive Hubbard model on the square lattice with the fluctuation exchange approximation. We have found the existence of (i) a transition between and pairing symmetries, (ii) -pairing in between the and CDW phases for intermediate and large , and (iii) for anisotropic cases the pairing symmetry changing, in agreement with a previously proposed “generic phase diagram,” as when (hence the charge fluctuations) are increased. All these are consequences of the structure in the charge and spin susceptibilities, which have peaks habitating at common or segregated positions in space.
1 More- Received 16 December 2003
DOI:https://doi.org/10.1103/PhysRevB.70.094523
©2004 American Physical Society