Ground state stability of δPu by way of introducing exact exchange within a DFT potential for correlated electrons

Delta phase in metallic plutonium is located at the transition from itinerant to localized electronic behaviour in the actinide series. Many models have been applied to this particular crystalline phase to unravel from first principles the elusive non-magnetic ground state observed experimentally. In this work structural and electronic ground-state properties are calculated where the possible magnetic states are compared to each other with the aid of a hybrid functional method as the high correlation approach (known as eece) implemented in the full potential LAPW code WIEN2k. Our results, obtained through a calculation procedure involving this high correlation model and the spin-orbit coupling term, show a feasible stability of the non-magnetic ground state of delta plutonium. The main contribution of the present work is the determination, under this level of theory, of approximate elastic constants of the non-magnetic ground state with zero total spin moment, thus confirming the mechanical stability of the crystal, which is in line with findings reported in previous works. (C) 2016 Elsevier B.V. All rights reserved.