The atomic and electronic structures of Ga and N interstitial created at the 8-interface of the (2¯5▪0) Σ = 19 (θ = 13.2°) tilt grain boundary in GaN were investigated by density-functional based tight-binding calculations. It was found that the structure of lowest energy of the Ga- or N-interstitial boundary was formed by a mixture of 6- and 5/7-atom rings (Gai- or Ni-interface) which was comparable to that of the 5/7-interface. The calculations showed that the non-stoichiometric Gai-interface was energetically more stable than was the stoichiometric 5/7-interface; suggesting that both configurations could exist.

Atomic Structure and Relative Stability of Gallium and Nitrogen Interstitials in GaN [0001] Grain Boundaries. A.Béré, I.Belabbas, S.Petit, G.Nouet, P.Ruterana, J.Chen, J.Koulidiati: Physica Status Solidi A, 2006, 203[9], 2176-80