Realistic many-body approach to materials with strong nonlocal correlations

针对具有强非局部相关性的材料的现实多体方法

• 批准号: 175297939
• 负责人: Professor Dr. Alexander Lichtenstein
• 金额: --
• 依托单位: I. Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/175297939?language=en
• 关键词: Realistic; many; body; approach; materials

Our project aims at substantial progress in the development of a realistic dynamical meanfield theory. This is achieved by advancing our present-day impurity solvers and by improving the interface to band theory. We employ optimized quantum Monte-Carlo techniques for the numerical evaluation of the recently developed dual-fermion approach which is extended for a general impurity model with several orbitals and sites. Our goal is to include non-local correlations beyond the single-site DMFT, to include long wave-length modes and to calculate dynamical two-particle correlation functions. These finite-temperature (T>0) methods are checked against a T=0solver that will be developed by using a recent reformulation of the (dynamical) density-matrix renormalization group in terms of matrix-product states. The prime goal is to provide and apply a T=0multi-orbital impurity solver without a sign problem and for real frequencies. Vital methodical progress is envisaged at the interface of DMFT to effective single-particle methods: This comprises tailored basis sets for an efficient representation of the correlated subspace, global charge self-consistency as well as access to phase diagrams and atomic forces due to a reliable scheme to compute the free energy. Correlated transition metals and compounds as well as correlation-induced insulators and frustrated lattice systems are considered.

我们的项目的目的是在一个现实的动态平均场理论的发展取得实质性进展。这是通过推进我们目前的杂质解决方案，并通过改善界面带理论。我们采用优化的量子蒙特-卡罗技术的数值评估最近开发的双费米子的方法，这是扩展到一个一般的杂质模型与几个轨道和网站。我们的目标是包括非本地的相关性超出单站点DMFT，包括长波长模式和计算动态的两粒子相关函数。这些有限温度（T>0）的方法检查对T= 0的求解器，将通过使用最近的（动态）密度矩阵重整化群的矩阵产品状态的重新制定。我们的主要目标是提供和应用一个T= 0的多轨道杂质求解器没有一个符号的问题，并为真实的频率。在DMFT与有效的单粒子方法的接口处，设想了重要的方法学进展：这包括定制的基组，用于有效地表示相关子空间、全局电荷自洽性以及由于计算自由能的可靠方案而获得相图和原子力。相关的过渡金属和化合物，以及相关诱导的绝缘体和阻挫晶格系统被认为是。