Construction of the First-Principles Non-Local Theory of Electron Correlations and Its Application to the Quasi-Two Dimensional Iron Compounds

为了定量描述关联电子系统的性质，我们将电子关联理论扩展到第一性原理和非定域理论。在T=0时，我们在自洽投影算符方法(SCPM)和LDA+U哈密顿量的基础上建立了第一原理非定域理论。此外，我们发展了动量依赖的局域-ansatz变分理论来计算第一原理SCPM中出现的静态关联函数。在有限温度下，我们基于非对角线有效介质和增量团簇展开，建立了考虑长程格点间关联的非局域动力学CPA。此外，我们还发展了第一原理分子动力学方法，它描述了高温近似下的非局域格点间关联。

In order to describe the properties of correlated electron systems quantitatively, we have extended our theories of electron correlations towards the first-principles and nonlocal theory. At T=0, we formulated the first-principles nonlocal theory on the basis of the self-consistent projection operator method (SCPM) and the LDA+U Hamiltonian. In addition, we developed the momentum-dependent local-ansatz variational theory to calculate the static correlation functions which appear in the 1st-principles SCPM. At finite temperatures, we formulated the nonlocal dynamical CPA which takes into account the long-range inter-site correlations on the basis of the off-diagonal effective medium and the incremental cluster expansion. Furthermorewe developed the first-principles molecular dynamics method which describes the nonlocal inter-site correlations within the high-temperature approximation.