INTERACTION OF OPTICAL PHONONS WITH ANISOTROPIC IMPERFECTIONS

Inelastic (Raman) light scattering by phonons interacting with anisotr opic imperfections is investigated. Three different kind of disorder-i nduced defects (point, linear and planar) have been considered. The op tical phonon width and line shape are found to depend importantly on t he dimension of the imperfections. There is a close correspondence bet ween the scale of the imperfection and the phonon line shape observed in the Raman scattering experiments. The dependence of the phonon freq uency shift and width on the defect concentrations is calculated, and the critical concentrations at which the optical phonon can no longer be observed are determined. (C) 1997 American Institute of Physics. [S 0021-3640(97)01324-8].