Pentagonal puckering in a sheet of amorphous graphene

TL;DR

This study uses density functional theory to explore how pentagons in amorphous graphene induce local curvature and puckering, revealing a lower-energy non-planar state with buckyball-like domes.

Contribution

It provides the first density functional analysis of topologically disordered amorphous graphene, highlighting the role of pentagons in inducing puckering and local curvature.

Findings

Pentagons induce local curvature in amorphous graphene.

A puckered state has lower energy than the planar configuration.

Local buckyball domes form around pentagons.

Abstract

Ordered graphene has been extensively studied. In this paper we undertake a first density functional study of it topologically disordered analogues of graphene, in the form of a random network, consisting predominantly of hexagonal rings, but also including pentagons and heptagons. After some preliminaries with crystalline material, we relax various random network models and find that the presence of carbon pentagons induce local curvature, thus breaking the initial planar symmetry, in some analogy with the case of fullerenes. Using density functional theory to calculate the total energy, we find that while the planar state is locally stable, there is a puckered state that has lower energy. The scale of the puckering is consistent with that expected with local maxima and minima associated with pentagons surrounded by larger rings; forming local "buckyball domes".