Plasmon transport in graphene investigated by time-resolved measurement

TL;DR

This paper demonstrates that the velocity of plasmons in graphene can be widely tuned using magnetic fields and gating, revealing edge magnetoplasmons with low loss and potential for nano-scale plasmonic devices.

Contribution

The study shows how to significantly tune graphene plasmon velocities via magnetic fields and gating, introducing the concept of edge magnetoplasmons with controllable properties.

Findings

Plasmon velocity in graphene can be tuned over two orders of magnitude.

Edge magnetoplasmons are formed at high magnetic fields.

Low-loss plasmon transport observed, suitable for nanostructure applications.

Abstract

Plasmons, which are collective charge oscillations, offer the potential to use optical signals in nano-scale electric circuits. Recently, plasmonics using graphene have attracted interest, particularly because of the tunable plasmon frequency through the carrier density $n$. However, the $n$ dependence of the plasmon velocity is weak ($\propto n^{1/4}$) and it is difficult to tune the frequency over orders of magnitude. Here, we demonstrate that the velocity of plasmons in graphene can be changed over two orders of magnitude by applying a magnetic field $B$ and by the presence/absence of a gate; at high $B$, edge magnetoplasmons (EMPs), which are plasmons localized at the sample edge, are formed and their velocity depends on $B$ and the gate screening effect. The wide range tunability of the velocity and the observed low-loss plasmon transport encourage designing graphene nanostructures for plasmonics applications.