  We study the correlation effects on the electronic structure and spin density
wave order in Fe-pnictides. Using the multiorbital Hubbard model and Gutzwiller
projection, we show that nonperturbative correlation effects are essential to
stabilize the metallic spin density wave phase for the intermediate correlation
strengths appropriate for pnictides. We find that the ordered moments depend
sensitively on the Hund's rule coupling $J$ but weakly on the intraorbital
Coulomb repulsion $U$, varying from $0.3\mu_B$ to $1.5\mu_B$ in the range
$J=0.3\sim0.8$ eV for $U=3\sim4$ eV. We obtain the phase diagram and discuss
the effects of orbital order and electron doping, the evolution of the Fermi
surface topology with the ordered moment, and compare to recent experiments.

Strongly Correlated Electrons;Superconductivity