DOPING DEPENDENCE OF THE SUSCEPTIBILITY IN THE 2-DIMENSIONAL HUBBARD-MODEL CLOSE TO HALF-FILLING

We use a theory developed in a previous paper [T. Kopp and F. Mila, Phys. Rev. B 43, 12 980 (1991)] to interpret recent Monte Carlo data relative to the doping dependence of the zero-temperature susceptibility of the Hubbard model on a square lattice. According to this theory, the susceptibility does not decrease, like the density of states, but increases upon doping, the essential reason being that the hopping processes that contribute to the susceptibility are suppressed close to half-filling because the wave functions on different sublattices have a vanishing overlap in that limit. We show that, for U/t=4, this theory is in very good agreement with recent Monte Carlo data. © 1994 The American Physical Society.