Polar optical oscillation modes in a semiconductor heterostructure

A recently proposed phenomenological theory for polar optical oscillations in semiconductor nanostructures is applied to the case of a system modeled as follows: a layer of a given material (e.g., GaAs) has one of its interfa ces free to oscillate mechanically (e.g., GaAs-air) while the other one is the interface with a semi-infinite semiconductor (e.g., GaAs-AlAs). To a ce rtain extent this model nanostructure could be addressed to the single hete rostructure case. By solving the system of four coupled differential equati ons involved in the theory analytical expressions for mode amplitudes and d ispersion relations are obtained. The present treatment, valid in the long wavelength limit, provides a full account of the electromechanical coupling of the oscillations and was applied successfully to other types of structu res. A detailed discussion of the obtained results is made.