Nanocircuits and Nanoimpedances of Nonmagnetic Plasmonic Nanoparticles From the Mie Theory Point of View

In this study, we show how the Mie theory fits into the recently proposed nanocircuitry for a spherical nanoscatterer. Because this theory must give the same results for the scattering problem as those provided by the dipole approximation, regardless of any particular electromagnetic response functions, a comparison is made between these two approaches for the internal and fringing nanoimpedances associated with the scattering of dielectric and plasmonic spheres. It is shown that, because of plasmonic resonances observed when the real part of the permittivity assumes a negative value, the simple dipole model, usually reliably adopted in the conventional positive refractive index case, must be used with care. This extends some previous works and provides a more complete picture of the physical nanoimpedance associated with the fringing fields, specially at the plasmonic resonances.