Boundary Scattering in Ballistic Graphene

TL;DR

This study investigates how boundary scattering affects magnetotransport in ballistic graphene nanowires, revealing a proportionality between cyclotron radius and wire width that differs from classical semiconductor systems.

Contribution

It provides the first detailed measurement of boundary scattering effects in ballistic graphene, highlighting a different proportionality constant than in traditional 2D electron systems.

Findings

Magnetoresistance peaks scale with W/R_c ≈ 0.9

Boundary scattering in graphene differs from classical semiconductors

Charge carrier mean free path is comparable to wire width

Abstract

We report magnetotransport measurements in ballistic graphene/hexagonal boron nitride mesoscopic wires where the charge carrier mean free path is comparable to wire width $W$. Magnetoresistance curves show characteristic peak structures where the peak field scales with the ratio of cyclotron radius $R_\textrm{c}$ and wire width $W$ as $W/R_\textrm{c} = 0.9 \pm 0.1$, due to diffusive boundary scattering. The obtained proportionality constant between $R_\textrm{c}$ and $W$ differs from that of a classical semiconductor 2D electron system where $W/R_\textrm{c} = 0.55$.