Polar optical vibration modes in semiconductor superlattices

The investigation of the polar optical vibration modes in semiconductor superlattices by different models are reviewed. It is emphasized that the simple analytic representations of the lattice modes calculated with the dipole oscillator model have introduced the double boundary condition that both the electrostatic potential and optical displacement vanish at the interfaces and have found wide acceptance. They have been referred to as the Huang-Zhu model. It is pointed out that its improved simulation version is essentially the dielectric continuum model taking account of phonon dispersion and subject to the double boundary condition.