Magnetoplasmons in quasi-neutral epitaxial graphene nanoribbons

TL;DR

This study investigates magnetoplasmon interactions in quasi-neutral epitaxial graphene nanoribbons, revealing hybrid modes with unique dispersion relations that differ from those in conventional graphene and two-dimensional systems.

Contribution

It provides the first detailed infrared spectroscopy analysis of inter-Landau-level excitations and hybrid modes in epitaxial graphene nanoribbons, highlighting deviations from standard magnetic-field dependencies.

Findings

Observation of deviation in Landau level transition energies

Identification of upper-hybrid mode formation

Distinct dispersion relation in the quantum regime

Abstract

We present infrared transmission spectroscopy study of the inter-Landau-level excitations in quasi-neutral epitaxial graphene nanoribbon arrays. We observed a substantial deviation in energy of the $L_{0(-1)}$$\to$$L_{1(0)}$ transition from the characteristic square root magnetic-field dependence of two-dimensional graphene. This deviation arises from the formation of upper-hybrid mode between the Landau level transition and the plasmon resonance. In the quantum regime the hybrid mode exhibits a distinct dispersion relation, markedly different from that expected for conventional two-dimensional systems and highly doped graphene.