Unified explanation of chemical ordering, the Slater-Pauling rule, and half-metallicity in full Heusler compounds

In the present work we developed an orbital coupling model for cubic full Heusler compounds that provides a unified set of rules that account for the chemical ordering, magnetic moment, and composition of the most promising candidates for half-metallicity. The origin and limitations of the rules are clearly described. To the best of our knowledge all of the several dozen half-metallic Heusler compounds known in the literature that follow the Mt=Nt-24 or Mt=Nt-28 generalized Slater-Pauling behavior satisfy the derived half-metallicity rule. Calculations performed by using density functional theory - performed for 259 compounds - confirm the validity of our model and derived rules for broad classes of Heusler compounds.