We present calculations of the optical absorption and electroabsorption spectra of graphene nanoribbons (GNRs) using a $\pi$-electron approach, incorporating long-range Coulomb interactions within the Pariser-Parr-Pople-model Hamiltonian. The approach is carefully benchmarked by computing quantities, such as the band structure, electric-field-driven half-metallicity, and linear optical absorption spectra of GNRs of various types, and the results are in good agreement with those obtained using ab initio calculations. Our predictions on the linear absorption spectra for the transversely polarized photons provide a means to characterize GNRs by optical probes. We also compute the electroabsorption spectra of the zigzag GNRs and argue that it can be used to determine whether or not they have a magnetic ground state, thereby allowing the edge magnetism to be probed through nonmagnetic experiments.

• Received 12 November 2010

DOI:https://doi.org/10.1103/PhysRevB.83.075413