Pu2O3晶体结构、弹性和电子性质的 密度泛函理论研究

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Pu_2O_3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Pu_2O_3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1.8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Pu_2O_3的Pu-5f加U能使体系从导体转变为绝缘体,这与实验测定Pu_2O_3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.

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

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.