Plasmons in layered superconductors

Collective modes of a layered electron gas are characterized by the presenc e of "acoustic" branches in addition to the usual optical plasmon branch. T he influence of such acoustic modes on superconducting properties is studie d within the strong-coupling phonon-plasmon scheme. Only the lowest acousti c branch at q(z) = pi and the optical branch at q(z) = 0 (where q(z) is the wave-vector perpendicular to the planes), for which the density-of-states (DOS) is peaked, are considered here. The effective plasmon-induced pairing interaction is given as a function of Matsubara frequency and T-c is calcu lated. (C) 2000 Elsevier Science B.V. All rights reserved.