In this work, we report the pressure dependence of the effective Coulomb interaction parameters (Hubbard U) in paramagnetic NiO within the constrained random phase approximation (cRPA). We consider five different low energy models starting from the most expensive one that treats both Ni-d and O-p states as correlated orbitals (dp-dp model) to the smallest possible two-orbital model comprising the eg states only (eg-eg model). We find that in all the considered models, the bare interactions are not very sensitive to the compression. However the partially screened interaction parameters show an almost linear increment as a function of compression, resulting from the substantial weakening of screening effects upon compression. This counterintuitive trend is explained from the specific characteristic changes of the basic electronic structure of this system. We further calculate the nearest neighbor inter-site d-d interaction terms which also show substantial enhancement due to compression. Our results for both the experimental and highly compressed structures reveal that the frequency dependence of the partially screened interactions can not be ignored in a realistic modeling of NiO. We also find that the computed interaction parameters for the antiferromagnetic NiO are almost identical to their paramagnetic counter parts.

翻译：在这项工作中,我们报告在受限制的随机阶段近似(cRPA)中,有效库伦相互作用参数(Hubbbard U)在负磁性NiO中的压力依赖度。我们考虑五种不同的低能模型,从将Ni-d和O-p状态视为相关轨道模型的最昂贵模型(dp-dp模型),到仅由等离子状态组成的最小的可能双轨模型(eg-eg模型),我们发现在所有考虑的模型中,光相互作用并不对压缩非常敏感。但部分筛选的相互作用参数显示,由于压缩时的筛选效果大大削弱,它是一种压缩功能,几乎是线性递增。这种反直觉趋势来自该系统基本电子结构的具体特点变化。我们进一步计算最近的相邻d-d-d互动条件,这些条件也显示压缩后会大大增强。我们实验和高度压缩结构的结果显示,在对NiO进行现实的模型中,部分筛选相互作用的频率依赖性不能忽视。我们还发现,反法磁号核部分的反面部分的计算结果几乎完全相同。