Analysis of a plasmonic core-shell particle exhibiting high-impedance and high-admittance characteristics

The feasibility of a core-shell particle to mimic the behavior of an RLC circuit is examined. In particular, under the quasi-static limit, the conditions are derived that allow for this type of particle to exhibit a high-impedance and a high-admittance response. These conditions dictate that the core and the shell are comprised of material characterized by positive and negative permittivity, respectively. The effective medium theory is employed and it is demonstrated that the equivalent permittivity of the particle under the aforementioned conditions becomes infinite and zero, respectively. A representative numerical example supports the theoretically derived results.