The behaviors of Ga and N vacancies (Schottky defects, Frenkel defects), lattice-site and interstitial Mg atoms, and interstitial H atoms were studied, in wurtzite-type crystals, by means of molecular dynamics simulations. The diffusion of interstitial Mg atoms on the (00▪1) plane predominated, as compared with the diffusivity along the [00▪1] direction. The diffusion coefficients of interstitial Mg atoms were described by 2 Arrhenius formulae for 850 to 2000K. One reflected the highly possible  occurrence of jumping movements among the cage centers of hexagonal crystal structure at higher temperatures. The other reflected the thermal vibration at the cage center for lower temperatures.

Magnesium Diffusion in Wurtzite-Type GaN Crystal. K.Harafuji, T.Tsuchiya, K.Kawamura: Physica Status Solidi C, 2003, 0[7], 2240-3