Transport properties of graphene across strain-induced nonuniform velocity profiles

TL;DR

This paper investigates how uniaxial strain affects ballistic transport in graphene, revealing shifts in Dirac points, deformation of Dirac cones, and their impact on tunneling, conductivity, and Fano factor in both uniform and nonuniform barrier structures.

Contribution

It introduces a model accounting for strain-induced Dirac cone deformation and nonuniform barriers, enhancing understanding of realistic graphene nanodevices with complex strain profiles.

Findings

Strain shifts Dirac points in reciprocal space.

Strain deforms Dirac cones affecting tunneling.

Transport properties are significantly altered by nonuniform strain profiles.

Abstract

We consider the effect of uniaxial strain on ballistic transport in graphene, across single and multiple tunneling barriers. Specifically, we show that applied strain not only shifts the position of the Dirac points in reciprocal space, but also induces a deformation of the Dirac cones, and that both effects are of the same order on the applied strain intensity. We therefore study the deviations thereby induced on the angular dependence of the tunneling transmission across a single barrier, as well as on the conductivity and Fano factor across a single barrier and a superstructure of several, periodically repeated, such sharp barriers. Our model is generalized to the case of nonuniform barriers, where either the strain or the gate potential profiles may depend continuously on position. This should afford a more accurate description of realistic `origami' nanodevices based on graphene, where `foldings' are expected to involve several lattice spacings.