First-principles local density approximation+U and generalized gradient approximation+U study of plutonium oxides

Abstract

The electronic structure and properties of PuO2 and Pu2O3 have been studied from first principles by the all-electron projector-augmented-wave method. The local density approximation+U and the generalized gradient approximation+U formalisms have been used to account for the strong on-site Coulomb repulsion among the localized Pu 5f electrons. We discuss how the properties of PuO2 and Pu2O3 are affected by the choice of U as well as the choice of exchange-correlation potential. Also, oxidation reaction of Pu2O3, leading to formation of PuO2, and its dependence on U and exchange-correlation potential have been studied. Our results show that by choosing an appropriate U, it is promising to correctly and consistently describe structural, electronic, and thermodynamic properties of PuO2 and Pu2O3, which enable the modeling of redox process involving Pu-based materials possible.

Screened Coulomb interaction calculations: cRPA implementation and applications to dynamical screening and self-consistency in uranium dioxide and cerium

“…The DFT+U method 1 or the combination of DFT with Dynamical Mean Field Theory method (DFT+DMFT) 2,3 have been successfully applied to a large number of systems in the last twenty years. In particular, these methods have been particularly useful to study the ground state and the photoemission spectra of Mott insulators such as bulk actinide [4][5][6][7][8][9][10][11] and lanthanide oxide [11][12][13][14][15][16] . For instance, to date DFT+DMFT is the only method to give a good description of photoemission spectra of both α and γ cerium [17][18][19][20][21][22] .…”

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

“…LDA + U with an approximate correction for the self-interaction correction (SIC) is employed [20]. Hubbard term of U = 0.294 Ry (4 eV) and J = 0.051 Ry (0.7 eV) for Pu and PuO 2 , which have been used widely [8,9,12,21].…”

“…Prodan et al found that PuO 2 was AFM by DFT and hybrid density functionals [6,7]. Sun et al performed calculation by DFT + U and obtained the same result [8]. More recently, Jomard et al provided a practical procedure which compared the energies of all energy minima with different initial occupation matrices (OM) and determined the ground state [9].…”

Atomistic simulation of interactions of fracture with defect clusters in delta-Pu

“…For the heavy actinides with localized 5f electrons, because of the strong electron-electron interaction, conventional DFT fails to capture the localization effect of 5f electrons. Pu lies at the boundary between the light actinides and the heavy actinides, so it exhibits abnormal behaviors [31]. At the present time, the better methods for dealing with Pu and Pu alloys are the hybrid exchange-correlation functional (such as B3LYP used in this paper), the self-interaction correction (SIC), the dynamics mean field theory (DMFT), and the local density approximation (LDA) or the generalized gradient approximation (GGA)+U (Hubbard U parameter represents a correction to Coulomb repulsion interaction) [32][33][34].…”