Impurity-assisted tunneling in graphene

TL;DR

This paper investigates how impurity-assisted resonant tunneling enhances electrical conductance in undoped graphene with smooth disorder, revealing the resonant nature and effects of disorder fluctuations.

Contribution

It introduces a transfer matrix approach to demonstrate resonant tunneling effects and models the impact of disorder fluctuations on conductivity in graphene.

Findings

Conductance increases due to impurity-assisted resonant tunneling.

Resonant character of conductivity enhancement is demonstrated.

Disorder fluctuations influence two-terminal conductivity.

Abstract

The electric conductance of a strip of undoped graphene increases in the presence of a disorder potential, which is smooth on atomic scales. The phenomenon is attributed to impurity-assisted resonant tunneling of massless Dirac fermions. Employing the transfer matrix approach we demonstrate the resonant character of the conductivity enhancement in the presence of a single impurity. We also calculate the two-terminal conductivity for the model with one-dimensional fluctuations of disorder potential by a mapping onto a problem of Anderson localization.