Particle-in-cell simulation of plasmons

Plasmons are collective oscillations of the free electron gas density in conducting media such as metals. In many cases of interest, plasmons are typically characterized by solving the Maxwell equations, where the electromagnetic response can be described by the bulk permittivity. Motivated by the physical similarity of plasmas and oscillating conduction electrons, we present a particle-in-cell-based method of simulating plasmons. By solving for the instantaneous particle position and momentum, which are connected to the electromagnetic fields through current, we demonstrate the capability of this novel approach in elucidating information on the formation of the plasmons. Specifically, we demonstrate plasmon formation in gold nanorods through laser irradiation and single-electron excitation. Lastly we investigate the non-local effects of ultra-small nanoparticles approaching quantum limit.