Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Phys Rev Lett. 2013 May 24;110(21):217212. doi: 10.1103/PhysRevLett.110.217212.
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.
我们在 L 吸收边进行了钙铱氧化物（CaIrO(3)）的共振 X 射线衍射实验，该化合物具有 (t(2g))^{5} 电子构型。通过观察磁信号，我们可以清楚地看到磁结构是带有沿 c 轴反铁磁矩的条纹有序，并且 t(2g) 空穴的波函数强烈地与自旋轨道纠缠，形成 J(eff)=1/2 态。观察到的自旋排列与预测在 J(eff)=1/2 态下存在独特超交换相互作用的理论工作一致，并指出了自旋轨道耦合在 Ir 氧化物中的普遍重要性，这与八面体连接和晶格拓扑无关。我们还提出，非磁性共振散射是揭示轨道态的有力工具，即使在金属铱酸盐中也是如此。
