Zigzag and armchair edges in graphene

Edges of finite size graphene, particularly nanographene, play an important role in giving unconventional electronic structure owing to the massless Dirac fermion features. This emerges as the creation of nonbonding edge state localized in the zigzag-shaped edges and electron wave interference in the armchair-shaped ones. We fabricated zigzag-edged and armchair-edged graphene nanoribbons, and investigated the Raman G-band and STM superlattice which are governed by the electron wave interference at the armchair edges.