Defect energetics in the Σ13 pyramidal twin grain boundary 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 grain boundary was similar to that in the bulk Al2O3, namely the

oxygen vacancy exhibited much higher formation energy than the aluminum

vacancy and the Schottky defect was the most preferable species in a wide range of

atmospheres. By analyzing the atomic structures of the grain boundary in detail, it

was found that the defect energetics at the GB was closely related to the structural

distortions, such as strains and dangling-bonds in the vicinity of the grain

boundary.

First Principles Calculations of Vacancy Formation Energies in Σ13 Pyramidal

Twin Grain Boundary of α-Al2O3. N.Takahashi, T.Mizoguchi, T.Tohei,

K.Nakamura, T.Nakagawa, N.Shibata, T.Yamamoto, Y.Ikuhara: Materials

Transactions, 2009, 50[5], 1019-22