  Hybrid density functionals, which replaces a fraction of density functional
theory (DFT) exchange with exact Hartree-Fock (HF) exchange, have been used to
study the structural, magnetic, and electronic properties of delta-Plutonium.
The fractions of exact Hartree-Fock exchange used were 25%, 40%, and 55%.
Compared to the pure PBE functional, the lattice constants expanded with
respect to the experimental value when the PBE-HF hybrid functionals were
applied. A non-magnetic ground state was realized for 55% HF contribution;
otherwise the ground state was anti-ferromagnetic. The 5f electrons tend to
exhibit slight delocalization or itinerancy for the pure PBE functional and
well-defined localization for the hybrid functionals, with the degree of 5f
electron localization increasing with the amount of HF exchange. Overall, the
performance of the hybrid density functionals do not seem superior to pure
density functionals for delta-Plutonium.
