The embedded-atom model was applied to the study of vacancy formation in the bulk. A systematic study was made of the sensitivity of the embedded-atom model potentials and embedding energy functionals as a function of the unrelaxed vacancy formation energy which was normally derived using ab initio density functional calculations. The effect of this so-called empirical input parameter upon the vacancy relaxation energy, formation volume and structural relaxation was also investigated by using super-cell sizes which were not normally accessible in orbital-based ab initio relaxation studies. It was found that, for Al, where a fifth-nearest neighbor model at most was required, the vacancy relaxation energy and formation volume were not sensitive functions of the unrelaxed vacancy formation energy. For Li, where a ninth-nearest neighbor model at least was needed, the situation was different. Both the vacancy relaxation energy and the formation volume were noticeably related to the unrelaxed vacancy formation energy. For both solids, the structural relaxation was largely insensitive to the unrelaxed vacancy formation energy, in good agreement with previous ab initio calculations. For Al, in particular, the embedded-atom model results agreed extremely well with recent orbital-free density functional calculations which used super-cell sizes that approached the ones which were used here. It was found that, for Li, the embedding energy functional had negligible curvature for a wide range of local electronic densities; thus justifying the use of a simpler pair-potential description for Li in slightly inhomogeneous systems.

The Embedded-Atom Model Applied to Vacancy Formation in Bulk Aluminium and Lithium. P.M.Derlet, R.Høier, R.Holmestad, K.Marthinsen, N.Ryum: Journal of Physics - Condensed Matter, 1999, 11[18], 3663-77