Electron correlation and spin density wave order in iron pnictides.

We study the correlation effects on the electronic structure, orbital and spin density wave (SDW) order in Fe pnictides. Using the multiorbital Hubbard model and Gutzwiller projection, we show that correlation effects are essential to stabilize the metallic SDW phase for the intermediate correlation strengths appropriate for pnictides. We find that the ordered moments depend sensitively on Hund's rule coupling J but weakly on the intraorbital Coulomb repulsion U, varying from 0.3μB to 1.5μB in the range J=0.3-0.8  eV for U=3-4  eV. We study the phase diagram, the evolution of the Fermi surface with the ordered moment, the effects of electron doping, and compare to recent experiments.