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

X射线共振散射理论及相关激发态从头计算方法的建立

• 批准号: 14540323
• 负责人: IGARASHI Jun-ichi
• 金额: $ 0.9万
• 依托单位: Japan Atomic Energy Research Institute
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14540323/
• 关键词: resonant x-ray scattering (RXS); resonant inelastic scattering (RIXS); K absorption edge; orbital order; magnetic order; 4p electronic state; spin-orbit interaction; 共鳴X線散乱; 磁気円二色性; 格子歪

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

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 ...更多信息 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

项目成果

J.Igarashi: "Lattice Distortion and Resonant X-Ray Scattering in DyB_2C_2"J.Phys.Soc.Jpn.. (掲載予定). (2003)

J.Igarashi：“DyB_2C_2 中的晶格畸变和共振 X 射线散射”J.Phys.Soc.Jpn..（即将出版）。

M.Usuda, M.Takahashi, J.Igarashi: "An Ab-Initio Calculation of Magnetic Resonant X-Ray Scattering Spectra in NiO"Phys.Rev.B. 69. 014408(1)-014408(7) (2004)

M.Usuda、M.Takahashi、J.Igarashi：“NiO 中磁共振 X 射线散射光谱的从头算”Phys.Rev.B。

T.Nagao: "Interference between Thomson Scattering and Resonant Scattering in X-Ray Diffraction from CeB_6"J.Phys.Soc.Jpn.. 72. 2381-2384 (2003)

T.Nagao：“来自 CeB_6 的 X 射线衍射中汤姆逊散射和共振散射之间的干涉”J.Phys.Soc.Jpn.. 72. 2381-2384 (2003)

Y.Nishikawa: "Resonant Inelastic X-Ray Scattering at the K Edge of Ge"J.Phys.Soc.Jpn.. (掲載予定). (2004)

Y.Nishikawa：“Ge K 边缘处的共振非弹性 X 射线散射”J.Phys.Soc.Jpn..（待出版）。

T.Nagao: "5d States and Resonant X-Ray Scattering from CeB_6"Surface Rev.Lett.. 9・2. 1203-1207 (2002)

T.Nagao：“来自 CeB_6 的 5d 状态和共振 X 射线散射”Surface Rev.Lett.. 9・2（2002 年）