Optical-phonon confinement and scattering in wurtzite heterostructures

We investigate Fr\"ohlich-like electron--optical-phonon interactions in wurtzite structures with single and double heterointerfaces based on the macroscopic dielectric continuum model and the uniaxial model. In addition to confined (for the case of double interfaces), interface, and half-space optical phonon modes as expected from the analogy with zinc-blende structures, propagating modes may exist in wurtzite heterosystems due to anisotropic phonon dispersion. This is especially the case when the dielectric properties of the adjacent heterostructure materials do not differ substantially. The dispersion relations and the interaction Hamiltonians for each of these modes are derived.