Tunable plasmonic reflection by bound 1D electron states in a 2D Dirac metal

TL;DR

This paper demonstrates that line-like perturbations hosting 1D electron states in 2D Dirac metals like graphene can be used to control plasmon reflection, with experimental evidence showing local conductivity enhancement via a nanotube gate.

Contribution

It introduces a method to tune plasmon reflection in 2D Dirac materials through bound 1D electron states controlled by electrostatic gating.

Findings

Enhanced local optical conductivity due to bound states

Experimental evidence of conductivity modulation with nanotube gate

Potential for tunable plasmonic devices

Abstract

We show that surface plasmons of a two-dimensional Dirac metal such as graphene can be reflected by line-like perturbations hosting one-dimensional electron states. The reflection originates from a strong enhancement of the local optical conductivity caused by optical transitions involving these bound states. We propose that the bound states can be systematically created, controlled, and liquidated by an ultranarrow electrostatic gate. Using infrared nanoimaging, we obtain experimental evidence for the locally enhanced conductivity of graphene induced by a carbon nanotube gate, which supports this theoretical concept.