Pu2O3晶体结构、弹性和电子性质的 密度泛函理论研究

The density functional theory studies of structural, elastic and electronic properties of Pu2O3

摘要:

采用基于密度泛函理论的全势能线性缀加平面波方法(FLAPW)，在局域自旋密度近似（LSDA：Local spin density approximation）和广义梯度近似（GGA: generalized gradient approximation）及LSDA/GGA+U下，系统研究了强关联5f电子体系Pu2O3的晶体结构，弹性参数，电子态密度和电荷密度。优化计算结果表明，LSDA+U的晶格参数a0和c/a与实验值吻合最好，同时也在不同的近似下计算了Pu2O3的弹性参数。与此同时，LSDA/GGA+U计算的态密度在费米能级处分别出现约1.8eV和2.2eV能隙，而LSDA/GGA的计算结果在费米能级处并无能隙，所以对Pu2O3的Pu-5f加U能使体系从导体转变为绝缘体，这与实验测定Pu2O3是绝缘性很好吻合。此外，电荷密度计算结果表明，与LSDA相比，LSDA+U计算的Pu-O间电荷密度增加且有明显的成键特征。

Abstract:

The structural, elastic and electronic properties of Pu2O3 have been investigated by means of the density functional theory using the full-potential linearized augmented plane wave (FLAPW) method and the local spin density approximation (LSDA) and the generalized gradient approximation (GGA) with on-site Coulomb repulsion U (LSDA/GGA+U) method. Our studies indicated the lattice parameters a0 and c/a of Pu2O3 are in good agreement with the corresponding experimental data, and elastic constants were reported in this article. At the same time, the density of states of Pu2O3 by LSDA/GGA+U appear 1.8eV and 2.2ev bandgap at the Fermi level, and LSDA/GGA calculation results in the formation of apparent contrast and therefore the U value of 5f in Pu makes the system change from a conductor to an insulator, which is in accord with the experiment. In addition, the charge density calculation results show that the charge density between Pu-O and LSDA is increased compared with LSDA+U, and it has obvious characteristics of bond formation.