Observation of spin-orbit excitations and Hund's multiplets in Ca2RuO4
Observation of spin-orbit excitations and Hund's multiplets in Ca2RuO4
复制标题
DOI：
10.1103/physrevb.100.045123
复制
发表时间：
2019-07-16
影响因子：
3.7
通讯作者：
Keimer, B.
中科院分区：
文献类型：
--
作者：
Gretarsson, H.;Suzuki, H.;Keimer, B.
我们用Ru-L-3边(2838.5 eV)共振非弹性x射线散射对Ca2RuO4的电子结构进行了量化，这是一种层状4d电子化合物，表现出关联驱动的金属-绝缘体转变和非传统的反铁磁性。我们观察到了一系列的Ru离子内跃迁，其能量和强度被模型计算很好地描述了。特别地，我们发现在320 meV处存在J=0->；2自旋轨道激发，并且在750 meV和1000 meV处存在洪德规则驱动的S=1->；0自旋态跃迁。这三个特征的能量唯一地决定了自旋-轨道耦合、四方晶场能量和洪德规则相互作用。从RIXS谱中推断的参数与用来解释反铁磁态的集体模的激子磁性图像非常一致。因此，Ru化合物和其他4d电子材料的L-3边RIXS可以直接测量对实际模型计算至关重要的相互作用参数。
We use Ru L-3-edge (2838.5 eV) resonant inelastic x-ray scattering (RIXS) to quantify the electronic structure of Ca2RuO4, a layered 4d-electron compound that exhibits a correlation-driven metal-insulator transition and unconventional antiferromagnetism. We observe a series of Ru intraionic transitions whose energies and intensities are well described by model calculations. In particular, we find a J = 0 -> 2 spin-orbit excitation at 320 meV, as well as Hund's-rule driven S = 1 -> 0 spin-state transitions at 750 and 1000 meV. The energy of these three features uniquely determines the spin-orbit coupling, tetragonal crystal-field energy, and Hund's rule interaction. The parameters inferred from the RIXS spectra are in excellent agreement with the picture of excitonic magnetism that has been devised to explain the collective modes of the antiferromagnetic state. L-3-edge RIXS of Ru compounds and other 4d-electron materials thus enables direct measurements of interactions parameters that are essential for realistic model calculations.