Carrier drift velocity and edge magnetoplasmons in graphene

TL;DR

This paper studies the behavior of edge magnetoplasmons in graphene, revealing quantized chiral propagation velocities and insights into carrier drift and Coulomb interaction lengths at the graphene edge.

Contribution

It provides the first detailed measurement of EMP propagation velocities and Coulomb interaction lengths in graphene edges, highlighting the effects of edge abruptness.

Findings

EMP propagation is chiral with low attenuation.

Propagation velocity is quantized on Hall plateaus.

Carrier drift velocity is slightly less than Fermi velocity.

Abstract

We investigate electron dynamics at the graphene edge by studying the propagation of collective edge magnetoplasmon (EMP) excitations. By timing the travel of narrow wave-packets on picosecond time scales around exfoliated samples, we find chiral propagation with low attenuation at a velocity which is quantized on Hall plateaus. We extract the carrier drift contribution from the EMP propagation and find it to be slightly less than the Fermi velocity, as expected for an abrupt edge. We also extract the characteristic length for Coulomb interaction at the edge and find it to be smaller than for soft, depletion edge systems.