Defect clustering in wustite

Atomistic simulation calculations based on the Mott-Littleton and supercell approaches have been used to investigate the geometries of defect clusters in Fe1-xO. Cluster binding energies and predicted lattice parameters are u sed as the basis of the analysis. The results clearly rule out some cluster s such as the [8:3] and [10:4] based on [100] stacking of [4:1] units and t he Koch-Cohen cluster. However, clusters based on the [111] spinel type sta cking and many based on the [110] type stacking yield results which are ver y close to experimental data and are energetically stable. This implies tha t at the lower end of the nonstoichiometry range a variety of different clu sters will coexist. (C) 1998 Elsevier Science Ltd. All rights reserved.