Theoretical studies on molecular magnetism and superconductivity with the generalized spin orbital(GSO)

分子团簇系统的电子、磁性和光学性质是人们十分感兴趣的，在理论处理中，它们通常属于强电子关联系统。因此，为了揭示功能磁性材料的作用机理，需要对自旋相关性进行研究。事实上，在由过渡金属组成的单分子磁体中，通过自旋挫挫和自旋简并实现非共线磁性。然而，通常的UHF和UDFT方法不能处理这样的系统，必须发展基于广义自旋轨道（GSO）的GHF和GDFT方法。本研究项目围绕这一主题，通过对数学群论的扩展、程序包的开发和计算机系统的定制，扩展了GSO的理论框架，开发了非共线磁体的从头计算程序包。例如，从头算HF（GHF）、GSO-LDA、GSO-GGA、GSO-LSDA+SIC和GSO-GW方法适用于这些目的。利用这些方法，明确了以下几点：（1）在自旋阻挫和自旋简并系统中，二维和三维自旋结构都是最稳定的。（2）当三重态氧分子离解成两个氧原子时，二维自旋结构是重要的。磁性参数（有效交换积分（J），各向异性参数（D））是研究磁性的重要参数，可以通过从头计算来计算。在这项研究中，评估计划的J和D值在非共线系统的发展。

Electronic, magnetic and optical properties in cluster systems of molecules are very interesting.In theoretical treatment, these commonly belong to strong electronic correlation systems. Thus, studies for spin correlation is strongly needed in order to reveal mechanism of functional magnetic materials. Indeed, in the single molecular magnets which are composed of transition metals, noncollinear magnetism is realized with spin frustration and spin degeneration. However, ordinary UHF and UDFT methods cannot treat such systems, and the GHF and GDFT methods based on generalized spin orbital (GSO) must be developed. In this research project, we approach these theme, through extension of mathematical group theory, developing of program package and custom making of computer system.We extended theoretical framework of GSO and developed program packages for ab initio calculation for noncollinear magnets. For example, ab initio HF (GHF), GSO-LDA, GSO-GGA, GSO-LSDA+SIC and GSO-GW methods are suitable for these purpose. Using these methods, the following points were made clear : (1)2- and 3- dimensional spin structure is most stable in both spin frustration and spin degenerate systems. (2)2-dimensinal spin structure is important, when triplet oxygen molecules are dissociated into two oxygen atoms. In addition, we applied them to many model systems.Magnetic parameters (effective exchange integral (J), anisotropic parameter (D)) are essential for investigation of magnetic properties and can be evaluated by ab initio calculation. In this study, evaluation scheme for both J and D values in noncollinear systems is developed.