1ST PRINCIPLE EVALUATION OF HYBRIDIZATION AND EXCHANGE EFFECTS FOR MAGNETIC-ORDERING IN CORRELATED-ELECTRON URANIUM SYSTEMS

Cerium and light actinide compounds show widely varied f-electron phenomena. The f-electron behavior in these systems ranges from well-localized to heavy-fermion-like or itinerant. Over a period of time we have been developing techniques to evaluate the fundamental interactions for correlated f-electron systems, such as band-f hybridization and band-f exchange, and trying to understand their properties and trends in the evolution of the properties between different isostructural cerium and light actinide compounds on the basis of absolute first principle calculations. Previous calculations are successful in explaining a variety of f-electron properties in cerium monopnictides and monochalcogenides. When going from localized f-electron cerium systems to more itinerant f-electron uranium systems, the hybridization between f- and non-f-conduction electrons is strongly enhanced by the self banding of the f states. We develop a scheme to evaluate the hybridization from the starting point that the f states are viewed as bands. We apply this scheme to uranium monopnictides and monochalcogenides to calculate their magnetic ordering.