Point Defect Energies for Strontium Titanate: A Pair-Potentials Study

A crystal potential has been derived for strontium titanate and used to calculate the intrinsic defect properties of the room temperature cubic phase. Interactive potentials for a number of uni-, di-, tri-, and tetra-valent metal ions with O2-, Sr2+, and Ti4 +has been derived by well-tried methods, using HFSCF calculations of the ionic charge densities and the conserved density approximation. Kinetic energy, exchange, and correlation contributions to the total interaction energy are approximated by the corresponding contributions to an electron gas of the same charge density as the sum of the two SCF ionic charge densities at each separationR. These impurity×host lattice potentials are then used to calculate the solubility of these ions in cubic SrTiO3as well as the possible mobility of these substituents.