Evidence from Raman Scattering for an Overdamped Soft Optic Mode in BaTiO3

Abstract
We report the temperature dependence of the Raman spectrum of the soft E mode in single-domain BaTiO3 and show that the unusually broad Raman line shape has the form expected for an overdamped vibrational mode. From a detailed line-shape analysis we obtain the undamped mode frequency and the damping constant of this soft mode.