PLASMONS IN A SUPERLATTICE IN A PARABOLIC QUANTUM-WELL

Well-defined plasma oscillations are observed in a superlattice miniba nd even though the Fermi energy lies in the minigap. Despite the compl ex band structure, the resonance shows a remarkable insensitivity to c hanges in the number of electrons in the parabolic well in which the s uperlattice is placed, a feature of the generalized Kohn theorem that is expected only in the limit that the Fermi energy is near the bottom of the lowest miniband. (C) 1995 American Institute of Physics.