First Principles Calculations of Atomic and Electronic Structure of TiAl3+- and TiAl2+-Doped YAlO.

In this paper, the density functional theory accompanied with linear combination of atomic orbitals (LCAO) method is applied to study the atomic and electronic structure of the Ti and Ti ions substituted for the host Al atom in orthorhombic bulk YAlO crystals. The disordered crystalline structure of YAlO was modelled in a large supercell containing 160 atoms, allowing simulation of a substitutional dopant with a concentration of about 3%. In the case of the Ti-doped YAlO, compensated -center (oxygen vacancy with two trapped electrons) is inserted close to the Ti to make the unit cell neutral. Changes of the interatomic distances and angles between the chemical bonds in the defect-containing lattices were analyzed and quantified. The positions of various defect levels in the host band gap were determined.