Exciton transport and exchange self-energy in semiconducting carbon nanotubes

We present direct measurements of $S_1$ exciton transport in (6,5) carbon nanotubes. Exciton diffusion lengths associated with end quenching, photoluminescence lifetimes, and homogeneous emission linewidths provide a basis for determining an intrinsic diffusion constant of 5 cm$^2$s$^{-1}$ within the dispersion of light. Exciton diffusion is modeled in terms of an anomalous dispersion within a marginal Fermi liquid description of the exciton exchange self-energy and acoustic phonon scattering.