ANTIFERROMAGNETIC SYMMETRY-BREAKING IN THE HALF-FILLED HUBBARD-MODEL IN INFINITE DIMENSIONS

We study the half-filled Hubbard model on a hypercubic lattice in infi nite dimensions in the presence of a staggered magnetic field. Using t he analyticity of the Anderson impurity model and assuming that for sm all enough on-site repulsion U the high-temperature phase is a Fermi l iquid, we show that at weak coupling the nesting property of the non-i nteracting band-structure necessarily leads to antiferromagnetic symme try breaking at a finite temperature.