Effects of cluster-cluster interactions on the structure and magnetic properties in (Fe6)2

The structure and magnetic properties of the coupled Fe-6:Fe-6 cluster have been systematically studied with the density functional formalism, and the Kohn-Sham equation is solved self-consistently with the discrete variational method (DVM). It is found that as the intercluster distance decreases the clusters are deformed, which results in the sensitive changes of magnetic moments. The cluster-cluster coupling energy indicates that the two clusters are weakly coupled, and the HOMO-LUMO gap of the coupled clusters is so small that the two coupled Fe-6 clusters are nearly metallic, and the metal-nonmetal transition can be realized by coupling and decoupling of clusters. (C) 1998 Elsevier Science S.A.