The structural relaxations and the formation energies of intrinsic defects in cubic

and orthorhombic CaTiO3 were investigated by a first principles projectoraugmented

wave method. It was found that cations and oxygen vacancies in both

phases cause extra levels near the valence band maximum and the conduction band

minimum, respectively, and the Ti-vacancy induced level in orthorhombic CaTiO3

was closer to the valence band maximum than that in cubic CaTiO3. Among the

neutral defect species, including neutral isolated vacancy, partial Schottky, and full

Schottky, it was found that the VCa

2-+VO

2+ and VO

0 were the most preferable defect

species for orthorhombic CaTiO3 under reduction and oxidization conditions,

respectively, whereas the VCa

2-+VO

2+ partial Schottky was always stable in any

atmosphere in cubic CaTiO3. As compared to cubic CaTiO3, it was found that

orthorhombic CaTiO3 exhibited higher defect formation energies.

First Principles Study on Intrinsic Vacancies in Cubic and Orthorhombic CaTiO3.

H.Lee, T.Mizoguchi, T.Yamamoto, Y.Ikuhara: Materials Transactions, 2009,

50[5], 977-83