Cancellation of spin and orbital magnetic moments in δ-Pu: Theory

Density functional theory (DFT), in conjunction with the fixed-spin-moment (FSM) method, spin-orbit coupling (SO), and orbital polarization (OP), is shown to retain key features of the conventional DFT treatment of δ-Pu while at the same time not producing the substantial net magnetic moments commonly predicted by this theory. It is shown that when a small adjustment of the spin moment (less than 20%) is allowed, a complete spin- and orbital-moment cancellation occurs which results in a zero net magnetic moment in δ-Pu. This minor modification, accomplished by the FSM method, is shown to have a very small effect on the calculated total energy as well as the electron density-of-states (DOS). The photoemission spectra (PES), obtained from the DOS of the present model, compares equal or better to measured spectra, than that of two other recent non-magnetic models for δ-Pu.