Polar optical oscillation modes in GaAs-based double heterostructures: Long wavelength limit

Applying a theory developed in previous works we calculated the polar oscillation modes of a DHS (double heterostructure) of the GaAs/AlAs prototype in the long wavelength limit. The material for each layer of the structure is modelled as an isotropic continuum. We report general analytical solutions of the fundamental equations involved in the theory, allowing in principle to study an arbitrary structure of the same type with N interfaces. For the DHS case we report amplitudes and potentials as a function of coordinates for the various oscillation modes, as well as dispersion-relation curves. Our results show good agreement with experimental data and also an excellent coincidence with ab initio microscopic calculations even for relatively large values of the in-plane wavevector. (author). 21 refs, 6 figs