First-principles study of surface properties of crystalline and amorphous uranium aluminides

Mei, Zhi-Gang; Yacout, Abdellatif M.

doi:10.1016/j.apsusc.2019.144132

Cited by 6 publications

(1 citation statement)

References 30 publications

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“…The conclusion is that DFT, with the GGA for the electron exchange and correlations, is sufficient for all studied actinide metals (no Hubbard U needed). Recently, numerous others came to the same conclusion [65][66][67][68] for uranium. For plutonium, however, treating the orbital-orbital interaction is necessary for a good electronic structure, total energy, and magnetic form factor [69].…”

Section: Discussionmentioning

confidence: 87%

Assessing Relativistic Effects and Electron Correlation in the Actinide Metals Th to Pu

et al. 2019

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Density functional theory (DFT) calculations are employed to explore and assess the effects of the relativistic spin-orbit interaction and electron correlations in the actinide elements. Specifically, we address electron correlations in terms of an intra-atomic Coulomb interaction with a Hubbard U parameter (DFT + U). Contrary to recent beliefs, we show that for the ground-state properties of the light actinide elements Th to Pu, the DFT + U makes its best predictions for U = 0. Actually, our modeling suggests that the most popular DFT + U formulation leads to the wrong ground-state phase for plutonium. Instead, extending DFT and the generalized gradient approximation (GGA) with orbital-orbital interaction (orbital polarization; OP) is the most accurate approach. We believe the confusion in the literature on the subject mostly originates from incorrectly accounting for the spin-orbit (SO) interaction for the p 1/2 state, which is not treated in any of the widely used pseudopotential plane-wave codes. Here, we show that for the actinides it suffices to simply discard the SO coupling for the p states for excellent accuracy. We thus describe a formalism within the projector-augmented-wave (PAW) scheme that allows for spin-orbit coupling, orbital polarization, and non-collinear magnetism, while retaining an efficient calculation of Hellmann-Feynman forces. We present results of the ground-state phases of all the light actinide metals (Th to Pu). Furthermore, we conclude that the contribution from OP is generally small, but substantial in plutonium.

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