First-principles calculation of positron states and annihilation parameters for group-III nitrides

We calculated theoretically positron states and annihilation parameters for VGa-C complexes in GaN. Positron lifetimes and Doppler-broadening S–W parameters were evaluated. The obtained results are compared other various types of defects in group-III nitrides. A random alloy In0.5Ga0.5N and its multilayer system together with GaN are investigated also. The results of the present study are expected to be useful for interpretation of experimental results on practical materials.