TEMPERATURE-DEPENDENT ELECTRONIC-STRUCTURE AND FERROMAGNETISM IN THE D=INFINITY HUBBARD-MODEL STUDIED BY A MODIFIED PERTURBATION-THEORY

The infinite-dimensional Hubbard model is studied by means of a modifi ed perturbation theory. The approach reduces to the iterative perturba tion theory for weak coupling. It is exact in the atomic limit and cor rectly reproduces the dispersions and the weights of the Hubbard bands in the strong-coupling regime for arbitrary fillings. Results are pre sented for the hypercubic and an fee-type lattice. For the latter we f ind ferromagnetic solutions. The filling-dependent Curie temperature i s compared with the results of a recent quantum Monte Carlo study.