# Negative Landau damping in bilayer graphene

## TL;DR

This paper theoretically shows that coupled graphene sheets can exhibit negative Landau damping, enabling plasmon amplification and light emission in the mid-infrared range through drift-induced instabilities.

## Contribution

It introduces a novel negative damping regime in bilayer graphene systems driven by DC current, linking wave instabilities to moving media phenomena.

## Key findings

- Demonstrates negative Landau damping in bilayer graphene
- Predicts spontaneous light emission (spasing) due to drift currents
- Highlights potential applications in nanophotonic on-chip light sources

## Abstract

We theoretically demonstrate that a system formed by two coupled graphene sheets enables a negative damping regime wherein graphene plasmons are pumped by a DC current. This effect is triggered by electrons drifting through one of the graphene sheets and leads to the spontaneous light emission (spasing) and wave instabilities in the mid-infrared range. It is shown that there is a deep link between the drift-induced instabilities and wave instabilities in moving media, as both result from the hybridization of oscillators with oppositely signed frequencies. With a thickness of few nanometers and wide spectral tunability, the proposed structure may find interesting applications in nanophotonic circuitry as an on-chip light source.

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Source: https://tomesphere.com/paper/1703.03623