The Origin of Raman D Band: Bonding and Antibonding Orbitals in Graphene

In Raman spectroscopy of graphite and graphene, the D band at ～ 1355 cm ？1 is used as the indication of the dirtiness of a sample. However, our analysis suggests that the physics behind the D band is closely related to a very clear idea for describing a molecule, namely bonding and antibonding orbitals in graphene. In this paper, we review our recent work on the mechanism for activating the D band at a graphene edge.