Vibrational properties and Raman spectra of different edge graphene nanoribbons, studied by first-principles calculations

The vibrational properties and Raman spectra of graphene nanoribbons with six different edges have been studied by using the first-principles calculations. It is found that edge reconstruction leads to the emergence of localized vibrational modes and new topological defect modes, making the different edges identified by polarized Raman spectra. The radial breathing-like modes are found to be independent of the edge structures, while the G-band-related modes are affected by different edge structures. Our results suggest that the polarized Raman spectrum could be a powerful experimental tool for distinguishing the GNRs with different edge structures due to their different vibrational properties.

► zz-57 GNR is the most stable edge structure compared with other five edge GNRs.
► New topological defect modes and edge modes could be used to distinguish edge structures.
► The radial breathing-like mode (RBLM) frequencies are independent of the edge structures
► The G-band-related modes are affected by different edge structures.