Magneto-orbital coupling in iron pnictides

Abstract A magneto-orbital coupling mechanism is proposed to account for the weak energy gap at the Fermi energy in the ( π , 0 ) ordered SDW state of a realistic three-orbital model for iron pnictides involving d xz , d yz , and d xy Fe orbitals. The orbital mixing terms between the d xy and d xz / d yz orbitals, which are important in reproducing the orbital composition of the elliptical electron pockets at ( ± π , 0 ) and ( 0 , ± π ) , are shown to play a key role in the energy gap formation in the SDW state.