Optical lattice vibrations in a zinc-blende superlattice consisting of periodically inverted polar domains are theoretically investigated and phonon dispersion curves are obtained. The salient features of the phonon dispersion are the mixing of longitudinal and transverse optical phonons and zone folding at twice the superlattice wave vector. The patterns of sublattice displacement and electric field are obtained and analyzed. The most interesting feature is the change in symmetry between the displacement and the electrical field, leading to different selection rules for various photon-phonon and carrier-phonon interactions.

• Received 13 June 2003

DOI:https://doi.org/10.1103/PhysRevB.70.085319