First-Principles Calculations of Titanium Dopants in Alumina
First-principles pseudopotential calculations were performed to investigate atomic and electronic structures of titanium (Ti) dopants in alumina (Al2O3). It was found that a substitutional Ti3+ defect induced an extra level occupied by one electron within the band gap of Al2O3. When two or more substitutional Ti3+ defects were located closely to each other, the defect-induced levels exhibited strong bonding interactions, and their formation energies decreased with increasing numbers of Ti3+ defects. This indicates that association and clustering of substitutional Ti3+ defects in Al2O3 can take place due to the interaction of the defect-induced levels.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
K. Matsunaga et al., "First-Principles Calculations of Titanium Dopants in Alumina", Materials Science Forum, Vols. 475-479, pp. 3095-3098, 2005