Plasmon DOS in layered systems: two layers per unit cell

In this paper we present the partial and total DOS of the plasmons in a lay ered electron gas system consisting of two layers per unit cell using the R andom Phase Approximation. The description of a lattice in terms of conduct ing bilayers surrounded by a non-conducting medium can be seen as a first a pproximation to oxide superconductors like Bi2212 and Tl2212. The relevancy of the partial density of states for experimental probes like reflection E ELS will be briefly discussed. Preceding the exact description of the parti al DOS we will give a short summary of the derivation of the plasmon disper sion in a two layer/unit cell system [A. Griffin, A.J. Pindor, Phys. Rev. B 39 (1989) 11503] and describe the two different branches that emerge. Fina lly, the total DOS is calculated numerically and is compared to the one lay er/unit cell case. (C) 1999 Elsevier Science B.V. All rights reserved.