2009 Volume 50 Issue 5 Pages 1019-1022
Defect energetics in Σ13 pyramidal twin grain boundary (GB) of Al2O3 was investigated by a first principles projector-augmented wave method. It was found that the vacancy formation energy depends on the atomic site and the defect energetics at the GB is similar to that in the bulk Al2O3, namely the oxygen vacancy shows much higher formation energy than the aluminum vacancy and the Schottky defect is the most preferable species in a wide range of atmospheres. By analyzing the atomic structures of the GB in detail, it was found that the defect energetics at the GB is closely related to the structural distortions, such as strains and dangling-bonds in the vicinity of the GB.