In order to find relationships among the atomic structure, electronic structure, and

defect energetics, [001](310)Σ5 grain boundaries of SrTiO3 and BaTiO3 were

investigated by using first-principles calculations and high-resolution scanning

transmission electron microscopy. It was found that the rigid-body translations of

one grain with respect to the other were indispensable to obtain the stable grain

boundary structure, and the rigid-body translation played an important role to

reduce the structural distortions such as dangling bonds and strains. It was clearly

demonstrated that a fit of calculated structures with microscopy images was not

enough to determine the grain boundary structure unless O columns can be seen in

the microscopy image. Although the vacancy formation energy depends on the

atomic site, the defect energetics at the grain boundary was found to be similar to

that in the bulk. It was also found that Ti vacancy was more sensitive to the

structural distortions than Sr(Ba) and O vacancies. This would be caused by the

difference in the bonding character of Ti-O and Sr(Ba)-O. Through this study, the

atomic structures of the [001](310)Σ5 grain boundaries of SrTiO3 and BaTiO3 were

determined, and the characteristic electronic structures and defect energetics of

those grain boundaries were identified.

Atomic Structure, Electronic Structure, and Defect Energetics in [001](310)Σ5

Grain Boundaries of SrTiO3 and BaTiO3. M.Imaeda, T.Mizoguchi, Y.Sato,

H.S.Lee, S.D.Findlay, N.Shibata, T.Yamamoto, Y.Ikuhara: Physical Review B,

2008, 78[24], 245320