Sign reversal of the orbital moment via ligand states - art. no. 172405

It is demonstrated that the coupling between spin and orbital moments in ma gnetic systems may-for certain materials-be reversed from antiparallel to p arallel, via the influence of ligand states. This is exemplified by first-p rinciples calculations for an intermetallic compound VAu4, but the effect m ay be found also in other classes of materials. From a computational analys is of the influence of the ligand states, and from an expression based on p erturbation theory, we show that ligand states, that traditionally are know n only to quench the orbital moment, may produce anomalous orbital moments that violate Hunds third rule.