Discrete Plasmons in Finite Semiconductor Multilayers

Abstract
We observe discrete plasmons in layered 2D electron gases with a large, but finte, number of periods. The twofold degeneracy of plasmon modes with wave numbers in the first Brillouin zone of the infinite system is lifted by the loss of complete periodicity in the finite system. These characteristic discrete plasmon doublets are measured in inelastic-light-scattering spectra of multilayer GaAs/(AlGa)As heterostructures.