title: Resonant x-ray diffraction study of the strongly spin-orbit-coupled mott insulator CaIrO3.
abstract: We performed resonant x-ray diffraction experiments at the L absorption edges for the post-perovskite-type compound CaIrO(3) with a (t(2g))^{5} electronic configuration. By observing the magnetic signals, we could clearly see that the magnetic structure was a striped ordering with an antiferromagnetic moment along the c axis and that the wave function of a t(2g) hole is strongly spin-orbit entangled, the J(eff)=1/2 state. The observed spin arrangement is consistent with theoretical work predicting a unique superexchange interaction in the J(eff)=1/2 state and points to the universal importance of the spin-orbit coupling in Ir oxides, independent of the octahedral connectivity and lattice topology. We also propose that nonmagnetic resonant scattering is a powerful tool for unraveling an orbital state even in a metallic iridate.
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Ohgushi
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Yamaura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ohsumi
authors.forename: Kunihisa
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Soshi
authors.initials: S
authors.lastname: Takeshita
authors.forename: Akihisa
authors.initials: A
authors.lastname: Tokuda
authors.forename: Hidenori
authors.initials: H
authors.lastname: Takagi
authors.forename: Masaki
authors.initials: M
authors.lastname: Takata
authors.forename: Taka-hisa
authors.initials: TH
authors.lastname: Arima