Role Played by Surface Plasmons on Plasma Instability in Composite Layered Structures

TL;DR

This paper explores how surface plasmons in composite layered nano-structures can be engineered to induce plasma instabilities that generate radiation, with potential applications in nano-plasmonic devices.

Contribution

It demonstrates the control of surface plasmon instabilities in hybrid nano-structures involving graphene, silicene, or electron gases, enabling radiation sources.

Findings

Surface plasmon instabilities can be triggered by electric currents in layered structures.

The instability range depends on layer separation and material properties.

The proposed mechanism can be tuned for specific applications in electromagnetic devices.

Abstract

We demonstrate the engineering of a source of radiation from growing surface plasmons (charge density oscillations) in a composite nano-system. The considered hybrid nano-structure consists of a thick layer of a conducting substrate on whose surface a plasmon mode is activated conjoining a single or pair of thin sheets of either monolayer graphene, silicene or a two-dimensional electron gas as would occur at a hetero-interface. When an electric current is passed through either a layer or within the substrate, the low-frequency plasmons in the layer may bifurcate into separate streams due to the driving current. At a critical wave vector, determined by the separation between layers (if there are two) and their distance from the surface, their phase velocities may be in opposite directions and a surface plasmon instability leads to the emission of radiation (spiler). Spiler takes advantage of the flexibility of choosing its constituents to produce sources of radiation. The role of the substrate is to screen the Coulomb interaction between two layers or between a layer and the surface. The range of wave vectors where the instability is achieved may be adjusted by varying layer separation and type of material. Applications to detectors and other electromagnetic devices exploiting nano-plasmonics are discussed.