Evidence for Graphene Edges Beyond Zigzag and Armchair

TL;DR

This paper provides experimental evidence that the most stable graphene edges are reconstructed beyond the traditional zigzag and armchair types, highlighting the need to consider unconventional edges in future research.

Contribution

It confirms that zigzag edges are metastable and that reconstructed edges are more stable, expanding the understanding of graphene edge structures.

Findings

Reconstructed edges are more stable than zigzag edges.

Experimental evidence supports the existence of unconventional graphene edges.

Reconstruction alters the chemical properties of graphene edges.

Abstract

The edges of nanoscopic objects determine most of their properties. For this reason the edges of honeycomb carbon--always considered either zigzag- or armchair-like--need special attention. In this report we provide experimental evidence confirming a previous unexpected prediction: zigzag is a metastable edge, as its planar reconstruction lowers energy and forms the most stable graphene edge. Our evidence is based on re-analyzing a recent experiment. Since the reconstructed edge, along with other unconventional edges we discuss, has distinct chemical properties, this discovery urges for care in experiments and theory--we must enter the realm beyond zigzag and armchair.