Plasmons in layered superconductors

Abstract

Collective modes of a layered electron gas are characterized by the presence of "acoustic" branches in addition to the usual optical plasmon branch. The influence of such acoustic modes on superconducting properties is studied within the strong-coupling phonon-plasmon scheme. Only the lowest acoustic branch at qz = π and the optical branch at qz = 0 (where qz 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 Tc is calculated. © 2000 Elsevier Science B.V. All rights reserved.