Theory of magnetoplasmons in semiconductor superlattices in the perpendicular geometry: a Green-function approach

Abstract

In this paper electronic collective excitations of semiconducting superlattices in the presence of an external magnetic field are examined using a Green-function response theory. The applied magnetic field is taken to be parallel to the superlattice axis (or, perpendicular to the interfaces). The material layers are characterized by the frequency- and magnetic field-dependent dielectric tensors. The thicknesses of the constituent layers are assumed to be considerably large so that the “quantum size effects” can be neglected. The magnetoplasma excitations are characterized by the electromagnetic fields localized at and decaying exponentially away from the interfaces. The response theory applied for the first time to the study of magnetoplasmons in these periodic structures enables one to calculate the corresponding response functions associated with the electromagnetic fields which can in turn be used to derive almost all physical properties of the systems at hand. In spite of the mathematical complexity, we have been able to reproduce exactly the previously reported results which were obtained with different approaches. The impact and applications of the theory have been discussed briefly.