In 't Veld Yann, Schüler Malte, Wehling Tim O, Katsnelson Mikhail I, van Loon Erik G C P
Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, NL-6525 AJ Nijmegen, The Netherlands.
J Phys Condens Matter. 2019 Nov 20;31(46):465603. doi: 10.1088/1361-648X/ab36fe. Epub 2019 Jul 30.
The theory of correlated electrons is currently moving beyond the paradigmatic Hubbard U, towards the investigation of intersite Coulomb interactions. Recent investigations have revealed that these interactions are relevant for the quantitative description of realistic materials. Physically, intersite interactions are responsible for two rather different effects: screening and bandwidth renormalization. We use a variational principle to disentangle the roles of these two processes and study how appropriate the recently proposed Fock treatment of intersite interactions is in correlated systems. The magnitude of this effect in graphene is calculated based on cRPA values of the intersite interaction. We also apply the variational principle to benzene and find effective parameters comparable to those obtained by ab initio density matrix downfolding.
关联电子理论目前正超越典型的哈伯德U，朝着研究格点间库仑相互作用的方向发展。最近的研究表明，这些相互作用对于现实材料的定量描述至关重要。从物理角度来看，格点间相互作用会产生两种截然不同的效应：屏蔽和带宽重整化。我们使用变分原理来区分这两个过程的作用，并研究最近提出的对格点间相互作用的福克处理方法在关联系统中的适用性。基于格点间相互作用的cRPA值计算了石墨烯中这种效应的大小。我们还将变分原理应用于苯，并发现有效参数与通过从头算密度矩阵降阶得到的参数相当。
