title: Surface energies of AlN allotropes from first principles.
abstract: In this letter we present first-principles calculations of the surface energies of rock-salt (B1), zinc-blende (B3) and wurtzite (B4) AlN allotropes. Of several low-index facets, the highest energies are obtained for monoatomic surfaces (i.e. of only either Al or N atoms): [Formula: see text] and [Formula: see text]. The difference between Al- and N-terminated surfaces in these cases is less then 20 meV/Å2. The stoichiometric facets have energies lower by 100 meV/Å2or more. The obtained trends could be rationalized by a simple nearest-neighbour broken-bond model.
authors.affiliation: Montanuniversität Leoben, Franz-Josef-Straße 18, Leoben A-8700, Austria.
authors.forename: David
authors.initials: D
authors.lastname: Holec
authors.forename: Paul H
authors.initials: PH
authors.lastname: Mayrhofer
keywords: Aluminium nitride; Broken-bond model; Density functional theory; Surface energy