Theory of resonant x-ray scattering and the establishment of the ab initio calculation method of the associated excited states

从微观角度研究了共振X射线散射（RXS）的机制，得到了以下结果：弹性散射（1）分析了反铁磁体KCuF_3中Cu K边附近和NiO中Ni K边附近的磁超晶格点的RXS谱。考虑到自旋轨道相互作用，我们在局域密度近似下进行了从头计算。解释了各种实验事实，阐明了拉链带轨道极化的机制。(2)We采用考虑自旋轨道相互作用的从头计算方法，分析了反铁磁体UGa_3中Ga K边磁超晶格点的RXS谱。阐明了UGa_3的4p带的大轨道极化是由于U原子的大轨道矩通过Ga的4p态和U的5 f态的混合而产生的。实验 关于我们 通过分析自然地解释了大的光谱强度。(3)We在考虑Ce 4f-Ce 4f原子间相互作用的原子模型基础上，分析了CeB_6中四极有序超晶格点的RXS谱。在不考虑晶格畸变的情况下，很好地再现了共振散射和汤姆逊散射之间的干涉。非弹性散射（1）在从头计算的基础上，分析了Ge K边附近的共振非弹性散射（RIXS）谱。很好地再现了实验光谱，并阐明了光谱与能带图之间的关系。(2)We在d-p模型的基础上分析了La_2CuO_4中Cu K边附近的RIXS谱。用Hartree-Fock近似和无规相位近似计算了能谱，与实验符合得很好。阐明了谱峰随末态动量变化而移动的机制。少

We have studied the mechanism of the resonant x-ray scattering (RXS) from the microscopic viewpoint, and have obtained the following results :Elastic scattering(1)We have analyzed the RXS spectra at the magnetic superlattice spots around the Cu K edge in the antiferromagnet KCuF_3 and around the Ni K edge in NiO. Taking account of the spin-orbit interaction, we have carried out ab initio calculations within the local density approximation. We have explained various experimental facts, having clarified the mechanism of the orbital polarization on the zip band.(2)We have analyzed the RXS spectra at the magnetic superlattice spots around the Ga K edge in the antiferromagnet UGa_3 by carrying out the ab initio calculation with taking account of the spin-orbit interaction. We have clarified tha mechanism that the large orbital polarization in the 4p band of UGa3 arises from the large orbital moment of U atoms through the mixing between the Ga 4p states and the U 5f states. The experimental … More large spectral intensitieshave been explained naturally by the analysis.(3)We have analyzed the RXS spectra at the quadrupole ordering superlattice spots in CeB_6 on the basis of an atomic model including Ce4f-Ce4f interatomic interaction. The interference between the resonant scattering and the Thomson scattering found in the experiment have been well reproduced without assuming the lattice distortion.Inelastic scattering(1)We have analyzed the resonant inelastic scattering (RIXS) spectra around the Ge K edge on the basis of the ab initio calculation. The experimental spectra have been well reproduced, and the relation between the spectra and the band mapping has been clarified.(2)We have analyzed the RIXS spectra around the Cu K edge in La_2CuO_4 on the basis of the d-p model. Using the Hartree-Fock approximation together with the random phase approximation, we have calculated the spectra in good agreement with the experiment. We have clarified the mechanism for the move of the the spectral peak with varying final-state momenta. Less