We have studied lattice dynamic properties of SrTiO3 thin films from 5 to 300 K using metal-oxide bilayer Raman scattering. First-order zone-center optical phonons, symmetry forbidden in single crystals, have been observed in the thin films, indicating strain-induced lowering of symmetry. The asymmetric line shape of the TO2 phonon is interpreted as evidence for micropolar regions in the thin films, likely due to oxygen vacancies. The optical phonon lines and the asymmetry persist up to room temperature.
ASJC Scopus subject areas
- Physics and Astronomy(all)