Theory of resonant x-ray scattering in the systems with complex ordering

共振x射线散射（RXS）包括弹性和非弹性两个过程。前者和后者分别适用于基态和激发态的研究。在本研究中，我发展了定量分析RXS光谱的理论，特别是对于具有复杂有序模式的系统。本文分析了多自由度活动系统的非弹性过程和具有短程阶的系统的弹性过程，并推导了具有多极阶的系统的弹性过程。该理论已应用于一些铜酸盐、铱酸盐和稀土化合物，并成功地解释了实验结果并预测了有趣的结果，这为实现对这些系统性质的更深入理解提供了进展。

Resonant x-ray scattering (RXS) consists of elastic and inelastic processes. The former and latter are suitable for invesitigation of the ground and excited states, respectively. In this study, I have developed theories for analyzing the RXS spectra quantitatively, in particular, for the systems having complex ordering patterns. The inelastic process has been analyzed in the systems where multiple degrees of freedoms are active and those exhibit short range order, while the elastic process has been formulated in the systems possessing multipole order. The theories have been applied to some cuprates, iridate, and rare earth compounds and have succeeded in explaining the experimental results and predicting intriguing outcomes, which provide the progress in achieving the deeper understanding of the properties of such systems.