论文标题
DFT+U方法中UO $ _2 $的结构和电子特性研究中的相对论效应
Relativistic effects in the study of structure and electronic properties of UO$_2$ within DFT+U method
论文作者
论文摘要
为了研究包含沉重原子的晶体，重要的是要考虑相对论效应，因为接近原子核的轨道中的电子可以达到与真空中光相当的速度。在这项研究中，我们利用第一原理DFT+U方法分析了二氧化铀（UO2）的电子结构和几何特性，并使用三种公式：全相关，标量 - 相关主义和非相关主义。我们的发现表明，非相关方案产生的结果显着偏离了晶格常数和带隙的实验值。相比之下，标量相关方案为UO2的几何特性产生了高度准确的结果，因此对于大多数研究而言，足够了。但是，为了进行更精确的分析，应采用具有自旋轨道效应的全依赖性计算，这导致Kohn-Sham带隙增加$ 6.2 \％$，而与标量 - 利用主义方法相比，晶格常数的0.05 \％$降低。
To study crystals that contain heavy atoms, it is important to consider the relativistic effects, as electrons in orbitals close to the atom's nucleus can reach speeds comparable to that of light in a vacuum. In this study, we utilized the first-principles DFT+U method to analyze the electronic structure and geometric properties of uranium dioxide (UO2) using three formulations: full-relativistic, scalar-relativistic, and non-relativistic. Our findings demonstrate that the non-relativistic scheme produces results that deviate significantly from experimental values for both lattice constant and band gap. In contrast, the scalar-relativistic regime yields highly accurate results for the geometric properties of UO2, and is therefore sufficient for most studies. However, for a more precise analysis, the full-relativistic calculations with spin-orbit effects should be employed, which result in a $6.2\%$ increase in the Kohn-Sham band-gap and a $0.05\%$ decrease in the lattice constant compared to the scalar-relativistic approach.
