Abstract
A dynamic cluster quantum Monte Carlo approximation is used to study the effective pairing interaction of a two-dimensional Hubbard model with a near neighbor hopping and an onsite Coulomb interaction . The effective pairing interaction is characterized in terms of the momentum and frequency dependence of the eigenfunction of the leading eigenvalue of the irreducible particle-particle vertex. The momentum dependence of this eigenfunction is found to vary as over most of the Brillouin zone and its frequency dependence is determined by the particle-hole continuum which for large varies as several times . This implies that the effective pairing interaction is attractive for singlets formed between near-neighbor sites and retarded on a time scale set by . The strength of the pairing interaction measured by the size of the -wave eigenvalue peaks for of order of the bandwidth . It is found to increase as the system is underdoped.
2 More- Received 31 May 2006
DOI:https://doi.org/10.1103/PhysRevB.74.094513
©2006 American Physical Society