Phase diagrams of the two-dimensional one-band t-t' Hubbard model are
obtained within the two-patch and the temperature-cutoff many-patch
renormalization group approach. At small t' and at van Hove band fillings
antiferromagnetism dominates, while with increasing t' or changing filling
antiferromagnetism is replaced by d-wave superconductivity. Near t'=t/2 and
close to van Hove band fillings the system is unstable towards ferromagnetism.
Away from van Hove band fillings this ferromagnetic instability is replaced by
a region with dominating triplet p-wave superconducting correlations. The
results of the renormalization-group approach are compared with the mean-field
results and the results of the T-matrix approximation.Comment: 29 pages, 17 figure
