Physical mechanism on edge-dependent electrons transfer in graphene in mid infrared region.

In this paper, we report nanophotonic properties of single layer graphene with Zigzag and/or armchair edge in the region of Mid Infrared (Mid-IR). The photoinduced charge transfer of graphene can occur in electronic state transition of Mid-IR region, and then the transferred electrons can interact with the phonon of graphene at Mid-IR. The coupling excitation of photon and phonon (graphene plasmon) can results in photon-electron-phonon interactions, which can significantly enhance resonance Raman scattering of Mid-IR region, which is so called "graphene plasmon-enhanced resonance Raman scattering of Mid-IR region". The photoinduced charge transfers are strongly dependent on the kinds of edge structures of Zigzag and/or armchair, which are revealed by charge difference density. It is found that the edge structures of Zigzag and/or armchair play the most important role on the orientation of charge transfer. The analysis of molecular orbital Pipek-Mezey localization reveals the nature of edge structure on the occurrence or not photoinduced charge transfer. Our results can promote deeper understanding nanophotonic mechanism of Mid Infrared graphene and can be potentially used in the design of optical device based on Mid Infrared graphene.