Lattice dynamics and Raman spectra of SrTiO3

The three independent components of the second order Raman spectra of SrTiO3 have been measured at 300 K. They show a strong similarity to the second order spectra of SrO. Very recently, the lattice dynamics1 and the Raman spectra of SrO have been successfully explained on the basis of a nonlinear shell model. It is shown that a modified version of this model theory can be applied to the case of SrTiO3. The importance of the polarizability of the oxygen ion, in particular its intra-ionic anisotropy, for the phonon dispersion curves as well as for the Raman spectra is established. Our results are critically compared with those obtained by other authors.2–4