  We investigate the phase diagram of a two-band frustrated Hubbard model in
the framework of dynamical mean field theory. While a first-order phase
transition occurs from a paramagnetic (PM) metal to an antiferromagnetic (AF)
insulator when both bands are equally frustrated, an intermediate AF metallic
phase appears in each band at different $U_c$ values if only one of the two
bands is frustrated, resulting in continuous orbital-selective phase
transitions from PM metal to AF metal and AF metal to AF insulator. We argue
that such intermediate phases are possibly related to the puzzling AF metallic
state with small magnetization observed in undoped iron-pnictide
superconductors as well as to the pseudogap features observed in optical
experiments.
