Anisotropy on the Fermi surface of the two-dimensional Hubbard model

Abstract

We investigate anisotropic charge fluctuations in the two-dimensional Hubbard model at half-filling. By the quantum Monte Carlo method, we calculate a momentum-resolved charge compressibility (formula presented), which shows the effects of an infinitesimal doping. At the temperature (formula presented) (formula presented) shows a peak structure at the (±Π/2,±Π/2) points along the (formula presented) line. A similar peak structure is reproduced in the mean-field calculation for the d-wave pairing state or the staggered flux state. © 2002 The American Physical Society.