Universal plasmonic properties of two-dimensional nanoparticles possessing sharp corners

We investigate theoretically the impact of variable smoothing of corners of single metallic, two-dimensional nanoparticles (faceted nanowires) on the characteristics of their plasmonic resonances-the resonant frequencies, eigenfunctions, polarizability, and near fields-using the method of surface integral equations. This impact is very strong: Increasing sharpness of the corners leads to a strong separation of the plasmonic eigenfrequencies, a progressing localization of the surface charge at the corners, and a strong near-field enhancement of the light intensity. Dependences of the above characteristics on the apex angle and the corner curvature show striking universal features. The limit of nonsmoothed corners is found to be practically meaningless. DOI: 10.1103/PhysRevB.87.115406