First-principles total energy calculations were performed in order to investigate the interaction of a stacking fault with a p-type impurity in both zincblende and wurtzite GaN. For both structures, it was found that - in the presence of a stacking fault - the impurity level was a more localized state in the band-gap. In zincblende material, the minimum-energy position of the substitutional Mg atom was at the plane of the stacking fault. In wurtzite material, the substitutional Mg atom at the plane of the stacking fault was a local minimum, and the global minimum was substitutional Mg far from the fault. This behavior could be understood in terms of a packing effect which introduced a distinct strain-relief process, since the local structure of the stacking fault in zincblende was similar to that of fault-free wurtzite, and vice versa.

Stacking Fault Effects in Mg-Doped GaN. T.M.Schmidt, R.H.Miwa, W.Orellana, H.Chacham: Physical Review B, 2002, 65[3], 033205 (4pp)