Spin-orbital-polarized density functional theory approach to the materials physics of Pu metal and its alloys

We introduce non-collinear generalizations of the orbital-polarization (OP) functional extending the capabilities of spin-polarized density functional theory (SP-DFT). It is found that in the presence of strong spin-orbit (SO) coupling, the balance between the magnitudes of the induced static spin moments versus spin currents depends sensitively on the details of the OP functionals. We thus propose a generalized SP+SO+OP-DFT approach, which can accurately account for the structures and energies of different phases of Pu without requiring formation of large net spin moments. The new SP+SO+OP-DFT method is computationally expedient and allows for convergence to self-consistency of large supercells at reasonable computational cost.