Localized magnetoplasmon modes arising from broken translational symmetry in semiconductor superlattices

The electromagnetic propagator associated with the localized collective mag netoplasmon excitations in a semiconductor superlattice with broken transla tional symmetry is calculated analytically within linear response theory. W e discuss the properties of these collective excitations in both radiative and non-radiative regimes of the electromagnetic spectra. We find that low- frequency retarded modes arise when the surface density of carriers eta(d) at the symmetry-breaking layer is lower than the density eta(0) at the rema ining layers. Otherwise (eta(d) > eta(0)) a doubler of localized, high-freq uency magnetoplasmon-like modes occurs. The corresponding dispersion law an d power spectrum of these modes are shown.