Evidence for Graphene Edges Beyond Zigzag and Armchair

Abstract

The edges of nanoscopic objects determine most of their properties. For this reason the edges of honeycomb carbon—always considered either zigzag- or armchairlike—need special attention. In this Brief 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 reanalyzing 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.