The positive piezoconductive effect in graphene

TL;DR

This paper reports a positive piezoconductive effect in suspended bi- and multi-layer graphene, showing layer-dependent behavior due to strain-induced competition between interlayer coupling and intralayer transport, with implications for tuning graphene's electromechanical properties.

Contribution

It reveals a layer-dependent positive piezoconductive effect in graphene and explains it through numerical modeling, highlighting the role of interlayer interactions in electromechanical properties.

Findings

Most pronounced response in tri-layer graphene.

Effect explained by strain-induced competition between interlayer and intralayer transport.

Layer number can be used to tune graphene's electromechanical properties.

Abstract

As the thinnest conductive and elastic material, graphene is expected to play a crucial role in post-Moore era. Besides applications on electronic devices, graphene has shown great potential for nano-electromechanical systems. While interlayer interactions play a key role in modifying the electronic structures of layered materials, no attention has been given to their impact on electromechanical properties. Here we report the positive piezoconductive effect observed in suspended bi- and multi-layer graphene. The effect is highly layer number dependent and shows the most pronounced response for tri-layer graphene. The effect, and its dependence on the layer number, can be understood as resulting from the strain-induced competition between interlayer coupling and intralayer transport, as confirmed by the numerical calculations based on the non-equilibrium Green's function method. Our results enrich the understanding of graphene and point to layer number as a powerful tool for tuning the electromechanical properties of graphene for future applications.