First-principles study of the electronic structure and magnetism of CaIrO3

I study the electronic structure and magnetism of postperovskite CaIrO3 using first-principles calculations. The density functional calculations within the local density approximation without the combined effect of spin-orbit coupling and on-site Coulomb repulsion show the system to be metallic, which is in disagreement with the recent experimental evidences that show CaIrO3 to be an antiferromagnetic Mott insulator in the J(eff) = 1/2 state. However, when spin-orbit coupling is taken into account, the Ir t(2g) bands split into fully filled J(eff) = 3/2 bands and half-filled J(eff) = 1/2 bands. I find that spin-orbit coupling along with a modest on-site Coulomb repulsion opens a gap leading to a Mott insulating state. The ordering is antiferromagnetic along the c axis with total moments aligned antiparallel along the c axis and canted along the b axis.