Giant spin-orbit splitting in ultrathin Ir(111) film

Spin-orbit (SO) splitting in ultrathin Ir(111) film was examined on the basis of density functional theory. The states with giant SO splitting can be found in few-monolayer Ir film terminated by H atoms. They distribute in several bands. From projected wave function study, the giant SO splitting is mainly induced by the pz and dyz states. The origin of this orbital dependence is analyzed by the distribution of states on the film. The stability of states is also discussed when the Ir surface is covered with graphene or graphone (half-hydrogenated graphene). The hybridization of energy bands greatly influences the large SO splitting and the persistence of states.