Third Order Perturbation Analysis of Pairing Symmetry in Two-Dimensional Hubbard Model
Hirono Fukazawa, Kosaku Yamada
We study the superconducting instabilities of singlet and triplet pairing in a two-dimensional Hubbard model on the basis of the third-order perturbation theory (TOPT). We investigate the effect of the vertex correction that is given by TOPT, comparing with the study with only the second-order effective interaction. In our results, a stable p-wave pairing state spreads from low to intermediate electron density. A dx2-y2-wave pairing is dominant for the high density near a half-filling. It is shown that the vertex correction plays an essential role in making the p-wave pairing state dominant.
arXiv:cond-mat/0208057•Journal of the Physical Society of Japan•Jun 15, 2002•17 citations