Eur. Phys. J. B 23, 297-305 (2001)
https://doi.org/10.1007/s100510170048

The role of layer-thickness deviation in dispersion and structure of plasmons in finite superlattices

Department of Physics and Astronomy, Western Washington University, Bellingham, 98225, Washington, USA

Corresponding author: ^a bljohnso@physics.wwu.edu

Received: 16 April 2001
Revised: 6 July 2001
Published online: 15 October 2001

Abstract

We study the effects of layer thickness variations on the collective plasmon excitation modes of finite superlattices. Unlike other symmetry lowering mechanisms, thickness variation does not strongly localize the surface modes. We find that the reason for this insensitivity lies in the fact that the collective modes of a given finite structure must evolve continuously from the single-finite-superlattice at zero thickness deviation into modes of a pair of uncoupled finite structures at large thickness variation. We also show that this behavior is analogous to the evolution of molecular orbitals from atomic orbitals as the internuclear separation is reduced, in contrast to the analogy of the superlattice modes as a stack of coupled quantum wells. This emphasizes the difference between the electromagnetic symmetry of the finite superlattice and the structural symmetry.