Analysis of band-anticrossing model in GaNAs near localised states

Abstract

Replacing As by N in GaNAs leads to a strong perturbation of the conduction band structure, generally described using the band-anticrossing (BAC) model. We have solved the single particle Hamiltonian for a very large supercell containing randomly placed nitrogen and have calculated the fractional Γ character, localisation factor and the density of states in the supercell. Comparison of these results with those calculated by the 2-level BAC model confirms the validity of the BAC model at energies away from N state energies but highlights the role of disorder at energies close to the N state energy.