Plasmons in Infinite 2D Electron System Screened by the Disk-Shaped Metallic Gate

Abstract

We have examined the plasmon modes in infinite two-dimensional (2D) electron system (ES) with the finite-sized gate formed by a metallic disk over a 2D electron plane. Heretofore, such a problem has never been analytically considered. We have predicted that discrete plasmon modes exist in such a partly-gated system even though no voltage was applied to the gate. The plasmon spectrum has been characterized by the radial and azimuthal mode numbers. We used an analytical approach recently developed for the gate in the form of a metallic stripe [A.A. Zabolotnykh and V.A. Volkov, Phys. Rev. B 99, 165304 (2019)]. Under several reasonable assumptions, we analytically find plasmon frequencies and charge density distributions.