论文标题
Fock交换二维材料缺陷的非直率分数
Nonunique fraction of Fock exchange for defects in two-dimensional materials
论文作者
论文摘要
通过调查单层WS $ _2 $与混合功能的空缺和替代缺陷，我们发现没有唯一的Fock交换量同时满足了广义的Koopmans状况，并可以重现带隙和带边缘的位置。根据带隙来固定Fock交换的混合参数可能导致二维材料中的定性缺陷物理。取而代之的是，一旦将混合参数分别调整为缺陷和频带边缘，在$ GW $近似中实现了极好的一致性和多体扰动理论。我们表明，与独特的优化混合参数不同是二维系统固有的，因为频带边缘经历了减少的筛选，而局部缺陷则进行了散装筛选。
By investigating the vacancy and substitutional defects in monolayer WS$_2$ with hybrid functionals, we find that there is no unique amount of Fock exchange that concurrently satisfies the generalized Koopmans' condition and reproduces the band gap and band-edge positions. Fixing the mixing parameter of Fock exchange based upon the band gap can lead to qualitatively incorrect defect physics in two-dimensional materials. Instead, excellent agreement is achieved with experiment and many-body perturbation theory within $GW$ approximation once the mixing parameters are tuned individually for the defects and the band edges. We show the departure from a unique optimized mixing parameter is inherent to two-dimensional systems as the band edges experience a reduced screening whilst the localized defects are subject to bulklike screening.
