LDA + U study of Pu and PuO2 on ground state with spin–orbital coupling

In order to describe the structural, electronic and thermodynamic properties of δ-Pu and PuO2, first-principle calculation is performed with spin–orbital coupling. By applying the DFT + U and occupation matrix method, we obtain a good result close to the experimental data. All possible initial occupation matrices are tried to find the ground state. The Jahn–Teller distortion and the spin–orbital effect are discussed. The intermediate coupling is proven by PDOS analysis. Covalency between Pu and O atoms is proven by quantum theory of atoms in molecules. By PDOS, occupation matrix and Bader charge analysis, the 5f configurations of δ-Pu and PuO2 are investigated.

► In our paper, we use spin–orbital coupling to investigate PuO2, which is the first time as our knowledge.
► We also check initially the Jahn–Teller effect of PuO2.
► Based on the Bader charge analysis, the covalency of Pu and O atoms is clearly shown.