Charge-Carrier Screening in Single-Layer Graphene

TL;DR

This study investigates how charge-carrier screening affects the electronic structure and transport properties of single-layer graphene, revealing renormalization effects and increased mean free path due to impurity screening.

Contribution

It provides direct experimental evidence of how screening modifies the Dirac cone and transport characteristics in graphene, advancing understanding of electron-electron interactions.

Findings

Renormalization of Fermi velocity and Dirac cone distortion

Increase in electron mean free path due to impurity screening

Insights into fundamental electron-electron interactions at the Dirac point

Abstract

The effect of charge-carrier screening on the transport properties of a neutral graphene sheet is studied by directly probing its electronic structure. We find that the Fermi velocity, Dirac point velocity, and overall distortion of the Dirac cone are renormalized due to the screening of the electron-electron interaction in an unusual way. We also observe an increase of the electron mean free path due to the screening of charged impurities. These observations help us to understand the basis for the transport properties of graphene, as well as the fundamental physics of these interesting electron-electron interactions at the Dirac point crossing.