Li Jiachen, Zhu Tianyu
Department of Chemistry, Yale University, New Haven, CT, 06520, USA.
Faraday Discuss. 2024 Nov 6;254(0):641-652. doi: 10.1039/d4fd00068d.
Dynamical mean-field theory (DMFT) and its cluster extensions provide an efficient Green's function formalism to simulate spectral properties of periodic systems at the quantum many-body level. However, traditional cluster DMFT breaks translational invariance in solid-state materials, and the best strategy to capture non-local correlation effects within cluster DMFT remains elusive. In this work, we investigate the use of overlapping atom-centered impurity fragments in recently-developed all-orbital DMFT, where all local orbitals within the impurity are treated with high-level quantum chemistry impurity solvers. We demonstrate how the translational symmetry of the lattice self-energy can be restored by designing symmetry-adapted embedding problems, which results in an improved description of spectral functions in two-dimensional boron nitride monolayers and graphene at the levels of many-body perturbation theory (GW) and coupled-cluster theory. Furthermore, we study the convergence of self-energy and density of states as the embedding size is systematically expanded in one-shot and self-consistent DMFT calculations.
动态平均场理论（DMFT）及其团簇扩展提供了一种有效的格林函数形式，用于在量子多体水平上模拟周期性系统的光谱性质。然而，传统的团簇DMFT破坏了固态材料中的平移不变性，并且在团簇DMFT中捕捉非局域关联效应的最佳策略仍然难以捉摸。在这项工作中，我们研究了在最近发展的全轨道DMFT中使用重叠的以原子为中心的杂质片段，其中杂质内的所有局域轨道都用高级量子化学杂质求解器处理。我们展示了如何通过设计对称适应的嵌入问题来恢复晶格自能的平移对称性，这导致在多体微扰理论（GW）和耦合簇理论水平上对二维氮化硼单层和石墨烯中的光谱函数有了改进的描述。此外，我们研究了在一次性和自洽DMFT计算中，随着嵌入尺寸系统地扩大，自能和态密度的收敛情况。
