Radiation damage at the coherent anatase TiO2/SrTiO3TiO2/SrTiO3 interface under Ne ion irradiation

Epitaxial anatase TiO2TiO2 films with thickness of around 300 nm were deposited on SrTiO3SrTiO3 and irradiated with 250 keV Ne ions at room temperature. X-ray diffraction, Rutherford backscattering spectrometry, and transmission electron microscopy were used to characterize the microstructural changes under irradiation. Two primary features are observed in the irradiated material: a damaged layer with a high density of nano-sized defects including dislocation loops was observed in the TiO2TiO2 film and, near the TiO2/SrTiO3TiO2/SrTiO3 interface, a defect denuded zone formed on the TiO2TiO2 side while an amorphous layer formed on the SrTiO3SrTiO3 side. Atomistic calculations attribute the formation of both the defect-denuded zone and the interfacial amorphous layer not to the interaction between the irradiation induced defects and the TiO2/SrTiO3TiO2/SrTiO3 hetero-interface but rather differences in chemical potential and mobilities for defects in each of the two phases.