Recently, plasmonic edge and breathing modes are obtained by electron energy loss spectroscopy in aluminum nanotriangles and silver nanodisks. In this article, based on the free-electron gas model and the linear response theory, we have derived the energy absorption spectrum and charge distributions under applied external fields to study the plasmons sustained by two-dimensional disks. Plasmonic edge, center and breathing modes are further observed by the charge distributions. In addition, with the help of energy absorption spectrum, the evolutionary characteristics of plasmon modes with the system parameters such as size, atomic separation and electron filling are further confirmed, and the effect of different applied external fields on plasmon excitations is displayed.

近来，通过电子能量损失谱在铝纳米三角形和银纳米盘中获得了等离激元边缘和呼吸模式。在本文中，基于自由电子气体模型和线性响应理论，我们导出了应用外场下的能量吸收谱和电荷分布，以研究二维圆盘所维持的等离激元。电荷分布进一步观察到等离子边缘，中枢和呼吸模式。此外，借助能量吸收光谱，进一步确定了具有系统参数（如尺寸，原子分离和电子填充）的等离激元模式的演化特性，并显示了不同外加电场对等离激元激发的影响。