Localized interface optical phonon modes in a semi-infinite superlattice with a caplayer

Abstract

We investigate the existence and characteristics of the localized interface opticalphonon modes (IOPMs) in a semi-infinite AlAs–GaAs superlattice with a caplayer consisting of ternary mixed crystal Alx Ga1−x As inthe dielectric continuum approximation. We find that the introductionof two-mode behaviour of the ternary mixed crystal of the cap layer orthe semi-infinite uniform dielectric medium leads to rich and variedlocalized mode spectra with interesting features. Moreover, it is alsofound that the localized IOPMs are sensitive to the concentrationx, thethickness of the cap layer and the type of semi-infinite uniform dielectric medium.A brief analysis of these results is given. It is expected that the localized IOPMscan be artificially controlled by adjusting the parameters of the proposedmicro-structures.