Abnormal Electronic Transport in Disordered Graphene Nanoribbon

TL;DR

This paper studies how impurities with different potential ranges affect the electronic conductivity of disordered graphene nanoribbons, revealing distinct regimes and behaviors that align with experimental observations.

Contribution

It classifies the conductivity behavior into four regimes based on impurity potential range and density, providing a detailed understanding of disorder effects in graphene nanoribbons.

Findings

Long range impurities cause extremely low conductance.

Conductivity exhibits a linear dependence on Fermi energy.

A wide dip in conductivity appears near the Dirac point.

Abstract

We investigate the conductivity $\sigma$ of graphene nanoribbons with zigzag edges as a function of Fermi energy $E_F$ in the presence of the impurities with different potential range. The dependence of $\sigma(E_F)$ displays four different types of behavior, classified to different regimes of length scales decided by the impurity potential range and its density. Particularly, low density of long range impurities results in an extremely low conductance compared to the ballistic value, a linear dependence of $\sigma(E_F)$ and a wide dip near the Dirac point, due to the special properties of long range potential and edge states. These behaviors agree well with the results from a recent experiment by Miao \emph{et al.} (to appear in Science).