MAGNETIC ORDERING IN A TWO-DIMENSIONAL HUBBARD MODEL

We have used the fourth order perturbation expansion to construct the magnetic phase diagram of the two-dimensional Hubbard model. To the contrary of the three-dimensional case, a stable antiferromagnetic phase is found at the limit of (t/U)≃0 if the electron density n lies in the region 0.95magnetic structure factor regarding the antiferromagnetic ordering.