Inelastic scattering in a monolayer graphene sheet; a weak-localization study

TL;DR

This study investigates weak localization effects in a monolayer graphene sheet, revealing how chiral-symmetry-breaking scattering and electron-electron interactions influence quantum interference and phase coherence.

Contribution

It provides experimental insights into the role of elastic intervalley scattering and electron-electron interactions in weak localization in graphene.

Findings

Chiral-symmetry-breaking elastic scattering restores weak localization.

Electron-electron interactions dominate inelastic scattering.

Inelastic scattering is enhanced near the Dirac point due to electron-hole puddles.

Abstract

Charge carriers in a graphene sheet, a single layer of graphite, exhibit much distinctive characteristics to those in other two-dimensional electronic systems because of their chiral nature. In this report, we focus on the observation of weak localization in a graphene sheet exfoliated from a piece of natural graphite and nano-patterned into a Hall-bar geometry. Much stronger chiral-symmetry-breaking elastic intervalley scattering in our graphene sheet restores the conventional weak localization. The resulting carrier-density and temperature dependence of the phase coherence length reveal that the electron-electron interaction including a direct Coulomb interaction is the main inelastic scattering factor while electron-hole puddles enhance the inelastic scattering near the Dirac point.