物理学报Issue(9)：1-7,7.DOI:10.7498/aps.64.097101
二氧化铀电子结构和弹性性质的第一性原理研究∗
Study on the electronic structure and elastic constants of uranium dioxide by first principles
摘要
Abstract
The crystal structure, electronic structure and elastic constants of uranium dioxide are investigated using first-principles calculations, wherein the generalized gradient approximation and Hubbard U terms are used in the framework of density-functional theory. On-site Coulomb interactions with the simplified rotational invariant approach (the Dudarev approach), fully relativistic calculations for the core electrons (represented as a pseudopotential), and scalar relativistic approximations for the valence electrons are employed to account for the relativistic effects and electron correlation of 5f electrons in UO2. The Hubbard U parameters (Ueff =U−J, U =3.70 eV, J =0.40 eV) are derived by calculating the band gap width of UO2. In addition, the electron density of states calculation suggests that the following value of band gap is appropriate. The calculated lattice constant is 5.54 Å, and the band gap width is 2.17 eV which shows that UO2 is a semiconductor. Its density of states shows that the U 5f orbital contributes to the peaks immediately adjacent to the Fermi level, which agrees with the U 5f2 configuration, while the O 2p orbital plays a dominant role in the bonding band at approximately−6 to−2 eV. Results obtained above have been compared with available experimental data, and also discussed in relation to previous calculations. Above results are better than existing ones gained by others. Analyzing the density of states for different Hubbard U parameters, we find that the Hubbard U parameters can influence the distribution of U 5f electronic orbit.关键词
DFT+U/Ueff值/UO2/性质Key words
DFT+U/the Hubbard U parameters/UO2/property引用本文复制引用
范航,王珊珊,李玉红..二氧化铀电子结构和弹性性质的第一性原理研究∗[J].物理学报,2015,(9):1-7,7.基金项目
国家自然科学基金(批准号:11175076,11475076)资助的课题.* Project Supported by the National Natural Science Foudation of China (Grant Nos.11175065,11475076) （批准号:11175076,11475076）
