  Multi-orbital Hubbard model Hamiltonians for the undoped parent compounds of
the Fe-pnictide superconductors are here investigated using mean-field
techniques. For a realistic four-orbital model, our results show the existence
of an intermediate Hubbard U coupling regime where the mean-field ground state
has spin stripe magnetic order, as in neutron scattering experiments, while
remaining metallic, due to the phenomenon of band overlaps. The angle-resolved
photoemission intensity and Fermi surface of this magnetic and metallic state
are discussed. Other models are also investigated, including a two orbital
model where not only the mean-field technique can be used, but also Exact
Diagonalization in small clusters and the Variational Cluster Approximation in
the bulk. The combined results of the three techniques point toward the
existence of an intermediate-coupling magnetic and metallic state in the
two-orbital model, similar to the intermediate coupling mean-field state of the
four-orbital model. We conclude that the state discussed here is compatible
with the experimentally known properties of the undoped Fe-pnictides.
