Magnetic superatoms in cage doped 13-atom trimetallic Mg n Li12− n Sc (n = 1–8) clusters and their assembled discrete supermolecules: a theoretical prediction

Abstract

Designing the novel cluster units is a major concern in the cluster assembled materials. With the aid of particle swarm optimization algorithm and density functional theory calculations, we have identified the geometric and electronic structures of 13-atom Mg n Li12−n Sc (n = 1–8) nanoclusters. The icosahedral structures are discovered as their respective global minima except Mg8Li4Sc, of which the cage structure is destroyed due to a magnesium atom outside the external metal cage. As the magnesium atoms increases, there is a sharp energy drop thereafter Mg5Li7Sc, and a large gain energy in Mg n Li12−n Sc (n = 3–5) is indicative of their especial stability. Molecular orbital analysis shows that the high stable clusters have the characteristics of magnetic superatoms. Then, the second stable magnetic cluster of Mg4Li8Sc is chosen as a possible building unit and the five-membered face-sharing motif is adopted. Mg4Li13Sc2 with the supermolecular properties are successfully constructed. Though the outer cage doped, this could to be a useful way to form the magnetic superatoms. Our findings further enrich building units that may aid in developing cluster-materials and tailoring their properties.