Piezoconductivity of gated suspended graphene

TL;DR

This paper studies how deformation and charge redistribution in gated suspended graphene affect its conductivity, revealing that small deformations enhance conductivity while larger ones suppress it, with potential experimental setups suggested.

Contribution

It provides a detailed analysis of the combined effects of lattice distortion and charge redistribution on graphene's conductivity using elasticity theory and transfer matrix methods.

Findings

Charge redistribution enhances conductivity at small deformations.

Lattice distortion suppresses conductivity at larger deformations.

Different deformation regimes have distinct impacts on graphene's electronic properties.

Abstract

We investigate the conductivity of graphene sheet deformed over a gate. The effect of the deformation on the conductivity is twofold: The lattice distortion can be represented as pseudovector potential in the Dirac equation formalism, whereas the gate causes inhomogeneous density redistribution. We use the elasticity theory to find the profile of the graphene sheet and then evaluate the conductivity by means of the transfer matrix approach. We find that the two effects provide functionally different contributions to the conductivity. For small deformations and not too high residual stress the correction due to the charge redistribution dominates and leads to the enhancement of the conductivity. For stronger deformations, the effect of the lattice distortion becomes more important and eventually leads to the suppression of the conductivity. We consider homogeneous as well as local deformation. We also suggest that the effect of the charge redistribution can be best measured in a setup containing two gates, one fixing the overall charge density and another one deforming graphene locally.