LOCAL SYMMETRY OF HYDROGEN IN CUBIC AND TETRAGONAL SRTIO3 AND KTAO3-LI DETERMINED BY POLARIZED RAMAN-SCATTERING

The OH stretch mode of hydrogen defect ensembles in cubic and tetragonal SrTiO3 and KTaO3:Li has been investigated with polarized Raman scattering. Introducing the Raman behavior type analysis to tetragonal crystals allows the determination of the local symmetry and proves for SrTiO3 that protons vibrate along the O-O bonds on the edges of the oxygen octahedron. Moreover, the different local symmetries of OH dipoles in antiferrodistortive SrTiO3 and KTaO3:Li with polar off-center Li(K) are reflected experimentally in the behavior type of the Raman scattering intensities.