title: Stable fourfold configurations for small vacancy clusters in silicon from ab initio calculations.
abstract: Using density-functional-theory calculations, we have identified new stable configurations for tri-, tetra-, and pentavacancies in silicon. These new configurations consist of combinations of a ring hexavacancy with three, two, or one interstitial atoms, respectively, such that all atoms remain fourfold. As a result, their formation energies are lower by 0.6, 1.0, and 0.6 eV, respectively, than the "part of a hexagonal ring" configurations, believed until now to be the lowest-energy states.
authors.affiliation: Département de Physique et Regroupement Québécois sur les Matériaux de Pointe, Université de Montréal, Case Postale 6128, Succursale Centre-Ville, Montréal, Québec H3C 3J7, Canada.
authors.forename: D V
authors.initials: DV
authors.lastname: Makhov
authors.forename: Laurent J
authors.initials: LJ
authors.lastname: Lewis