Abstract

Graphene nanoribbons (GNRs) are finite-width infinite stripes of carbon atoms arranged in a honeycomb lattice. The possibility of tuning their width as well as shaping their edge geometry provides a strategy to overcome the absence of an electronic gap in monolayer graphene, which prevents its application in optoelectronic devices. Besides this technological goal, these quasi-one-dimensional systems present unique opportunities to test quantum mechanical predictions related to low-dimensional phenomena in condensed matter. This contribution surveys the most recent theoretical advances in the investigation of excitonic many-body effects in armchair GNRs, which display an interesting family behavior in their excited-state electronic structure and optical properties. The exact diagonalization method of the Hubbard model applied in the low-intermediate correlation regime will be presented as a full many-body approach going beyond perturbative techniques for elucidating the excitonic fine structure of these systems and the family behavior of their optoelectronic properties. Optical interband transitions and selection rules for both longitudinally and transversely polarized photons are shown and compared to those known for systems of similar symmetry like zigzag single-walled carbon nanotubes. Further work suggestions for treating wider systems are provided in the end.