Green-function theory of confined plasmons in coaxial cylindrical geometries: Zero magnetic field

A theoretical investigation is made of the plasmon propagation in the coaxial cylindrical geometries using Green function (or response function) theory in the absence of an applied magnetic field. The plasmon excitations in such multiple interface structures are characterized by the electromagnetic (EM) fields that are localized at and decay exponentially away from the interfaces. The Green-function theory, generalized to be applicable to such quasi-one-dimensional (1D) systems, enables us to derive explicit expressions for the corresponding response functions (associated with EM fields), which can in turn be used to compute numerous physical properties of the system at hand. A rigorous analytical diagnosis of the general results in diverse situations leads us to reproduce exactly the previously well-established results on 2D and 1D systems, obtained within the different theoretical frameworks. As an application, we present several illustrative examples on the dispersion characteristics of the confined and extended plasmons in single- and double-interface structures. These dispersive modes are also substantiated through the computation of local as well as total density of states. Our theoretical framework can also serve as a powerful technique for studying the intrasubband plasmons in the emerging mutiple-walled carbon nanotubes. The elegance of theory lies in the fact that it does not require the matching of the messy boundary conditions and in its simplicity and the compact form of the desired results.