Insulating Behavior of an Amorphous Graphene Membrane

TL;DR

This study explores how topological disorder in amorphous graphene leads to insulating behavior, with electronic properties severely degraded and localization lengths as short as 5 nanometers.

Contribution

It demonstrates that topological disorder alone can induce Anderson insulating states in amorphous graphene, supported by detailed transport calculations.

Findings

Density of states increases near charge neutrality point

Electronic properties are significantly degraded by disorder

Localization length is approximately 5 nanometers

Abstract

We investigate the charge transport properties of planar amorphous graphene that is fully topologically disordered, in the form of sp2 three-fold coordinated networks consisting of hexagonal rings, but also including many pentagons and heptagons distributed in a random fashion. Using the Kubo transport methodology and the Lanczos method, the density of states, mean free paths and semiclassical conductivities of such amorphous graphene membranes are computed. Despite a large increase in the density of states close to the charge neutrality point, all electronic properties are dramatically degraded, evidencing an Anderson insulating state caused by topological disorder alone. These results are supported by Landauer-Buttiker conductance calculations, which show a localization length as short as 5 nanometers