A computational study was made of the N vacancy in the charge states, +3, +2 and +1, in AlN in the metastable zincblende phase. The vacancy and its 4 nearest-neighbour Al ions were treated as a molecular cluster, embedded in an infinite classical shell-model crystal. The following ground state properties, all of which were determinable from experiment, were calculated: total spin, nearest-neighbour displacement, electron spin density at nearest-neighbour nuclei and breathing-mode force constant. The issue of disproportionation among the three charge states was also addressed. Most importantly, the optical excitation energies were evaluated.

The Nitrogen Vacancy in Aluminium Nitride. J.M.Vail, D.K.Chevrier, R.Pandey, M.A.Blanco: Journal of Physics - Condensed Matter, 2006, 18, 2125-35