Impurity levels associated to Fe 3+ -V o , Fe 4+ -V o and Ti 4+ -V o centers in cubic perovskite crystals: Xα cluster analysis

The recent analysis of the local structure of transition-metal-oxygen-vacancy defets, M-Vo, trapped in a cubic SrTiO3 host (1), shows a distorsion of the local geometry. The M ion moves by about 0.2Å towards the vacancy site while the four oxygens in a plane perpendicular to the M-Vo axis are desplaced against the metal ion by about 0.08Å.