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

广义自旋轨道（GSO）分子磁学和超导理论研究

基本信息

批准号：
14204061
负责人：
YAMAGUCHI Kizashi
金额：
$ 30.12万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

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.

分子簇系统中的电子、磁和光学性质非常有趣。在理论处理中，这些通常属于强电子关联系统。因此，为了揭示功能磁性材料的机理，迫切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，非共线磁性是通过自旋挫败和自旋简并来实现的。然而，普通的UHF和UDFT方法无法处理此类系统，必须开发基于广义自旋轨道（GSO）的GHF和GDFT方法。在这个研究项目中，我们通过数学群论的扩展、程序包的开发和计算机系统的定制来实现这些主题。我们扩展了GSO的理论框架，并开发了用于非共线磁体从头计算的程序包。例如，从头开始 HF (GHF)、GSO-LDA、GSO-GGA、GSO-LSDA+SIC 和 GSO-GW 方法适合这些目的。使用这些方法，明确了以下几点：（1）2维和3维自旋结构在自旋挫败和自旋简并系统中都是最稳定的。 (2)当三线态氧分子解离成两个氧原子时，二维自旋结构很重要。此外，我们将它们应用到许多模型系统中。磁参数（有效交换积分（J）、各向异性参数（D））对于磁特性的研究至关重要，可以通过从头计算来评估。在本研究中，开发了非共线系统中 J 和 D 值的评估方案。