Multiple exciton generation by a single photon in single-walled carbon nanotubes.

Multiple-exciton generation in single-walled carbon nanotubes is investigated theoretically. We show that multiple excitons can be directly generated by a single photon through resonant coupling with multiexciton states. Further, the theoretically predicted threshold energy for this process is consistent with recent experimental results. Our calculations clarify the elementary processes of multiple-exciton generation in single-walled carbon nanotubes.