First-principles study of half-metallic properties in RbCaNZ (Z = O, S, and Se) quaternary Heusler compounds

On the basis of first principles calculations, the electronic structures and magnetic properties of quaternary Heusler alloys RbCaNZ (Z = O, S, and Se) were studied. The negative formation energies indicated that all these compounds were thermodynamically stable and thus may be experimentally synthesized at appropriate conditions in the future. The results showed that Y-I structure was the most favorable configuration among the three possible structures. All compounds were found to be half-metallic ferromagnets. The characteristic of energy bands and origin of half-metallicity were also verified. The total magnetic moments of RbCaNZ (Z = O, S, and Se) compounds were obtained 2 mu(B) per formula unit, which were in an agreement with Slater-Pauling rule (M-tot = 12 - Z(tot)). Half-metallicity was preserved at ranges of 5.06-8.36 angstrom, 5.96-8.81 angstrom, and 6.13-8.73 angstrom for RbCaNO, RbCaNS, and RbCaNSe compounds, respectively, which show that these quaternary Heusler compounds may be potential candidates in spintronic applications. (C) 2018 Elsevier B.V. All rights reserved.