By using a tight-binding based ab initio method, the atomic and electronic core structures of the threading (a+c)-mixed dislocation in wurtzite were investigated. For this dislocation, 2 core configurations were found: a 5/7-atom ring and a complex double 5/6-atom ring configuration. Both core configurations were found to induce levels in the band-gap as well deep as shallow gap states.

Investigation of the Atomic Core Structure of the (a+c)-Mixed Dislocation in Wurtzite GaN. I.Belabbas, A.Béré, J.Chen, P.Ruterana, G.Nouet: Physica Status Solidi C, 2007, 4[8], 2940-4