Electronic band gaps for optically allowed transitions are calculated for a series of
semiconducting single-walled zig-zag carbon nanotubes of increasing diameter within the
many-body perturbation theory GW method. The dependence of the evaluated gaps with
respect to tube diameters is then compared with those found from previous experimental
data for optical gaps combined with theoretical estimations of exciton binding energies. We
find that our GW gaps confirm the behavior inferred from experiment. The relationship …