Coupling and splitting of the plasmon modes in a superlattice with complex defect structures

Abstract

We study the properties of the localized interface plasmon modes (IPMs) arising from coupling and splitting of the plasmon eigenstates in two semiinfinite superlattices containing complex defect structures. Two kinds of defect structure are considered: one is a single quantum well, i.e., a barrier-wellbarrier structure; the other is a well-barrier-well structure. The influences of the constitution of the defect structures, as well as the physical and geometric parameters of the superlattices on the characteristics of the localized IPMs are investigated in detail. The numerical results show that the localized modes exhibit peculiar features; the complexity of the dispersion of IPMs is essentially associated with the coupling of the interwell regions in the defect structure, and the barrier and well layers play different roles in the features of the localized IPMs. We also present a comparison of the dispersions of the localized IPMs between these two types of defect structure and give a physical picture to explain these results.