Deformation of Fermi Surface Due to Antiferromagnetic Correlation

Abstract

It is investigated, on the basis of the fluctuation exchange approximation, how the shape of the Fermi surface is modified in two-dimensional $t-t'-U$ Hubbard model at half filling as strength of the onsite Coulomb interaction $U$ is increased. The antiferromagnetic (AF) correlation length is shown to be enhanced as the Coulomb interaction get closer to the critical value $U_{\rm c}$ for the onset AF order. At the same time, the shape of the renormalized Fermi surface is deformed showing the tendency of nesting near $U_{\rm c}$.