Optical properties of chiral graphene nanoribbons: a first principle study

Recent successes in unzipping carbon nanotubes have introduced a new member of graphene nanoribbons (GNRs) family known as chiral GNRs. In this paper, optical properties of chiral GNRs both in longitudinal and transverse polarizations of incident beam have been studied using Density Functional Theory. We have shown that the selection rules, which were previously reported for armchair and zigzag GNRs, are no longer valid due to breaking symmetries in this new family. However, we have demonstrated that the edge states play a critical role in the dielectric constant. It has been shown that, depending on the polarization of incident beam the absorption peaks are different, although they are spread in the same energy range. We also suggested that the absorption energy range is sensitive to the chiral vectors and the light polarization. Due to breaking symmetries in chiral GNRs, absorption peaks are changed becoming approximately 1000 nm, thus a new potential of GNRs for optoelectronic devices is introduced.