Surface-near modifications of SrTiO3 local symmetry due to nitrogen implantation investigated by grazing incidence XANES

Nitrogen ion implantation into strontium titanate single crystals causes a slight shift of the Ti-K edge position compared to pristine SrTiO3 and a strong increase of the second pre-edge peak in X-ray absorption near-edge spectroscopy (XANES) using graz- ing incidence geometry. Calculations by a finite difference method demonstrate that the strong increase of the second pre-edge fea- ture in the defect distorted phase can be attributed to a static displacement of the Ti atom relative to the surrounding oxygen octahedron.