title: Raman study on the g mode of graphene for determination of edge orientation.
abstract: We report a confocal Raman study on edges of single-layer graphene. It is found that edge orientations could be identified by G mode in addition to D mode. We observe that G mode at the edges of single-layer graphene exhibits polar behaviors and different edges such as zigzag- or armchair-dominated responses differently than the polarization of the incident laser. Moreover, G mode shows stiffening at zigzag-dominated edges, while it is softened at armchair-dominated ones. Our observations are in good agreement with recent theory (Sasaki, K. et al. J. Phys. Soc. Jpn. 2010, 79, 044603) and could be well-explained by the unique properties of pseudospin at graphene edges, which lead to asymmetry of Raman active modes and non-adiabatic processes (Kohn Anomaly) at different types of edges. This work could be useful for further study on the properties of the graphene edge and development of graphene-based devices.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
authors.forename: Chunxiao
authors.initials: C
authors.lastname: Cong
authors.forename: Ting
authors.initials: T
authors.lastname: Yu
authors.forename: Haomin
authors.initials: H
authors.lastname: Wang
mesh_terms: D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D006108:Graphite / Q000737:chemistry*; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012542:Scattering, Radiation; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D006108:Graphite