  We study the transport properties of defective single-walled armchair carbon
nanotubes (CNTs) on a mesoscopic length scale. Monovacancies and divancancies
are positioned randomly along the CNT. The calculations are based on a fast,
linearly scaling recursive Green's function formalism that allows us to treat
large systems quantum-mechanically. The electronic structure of the CNT is
described by a density-functional-based tight-binding model. We determine the
influence of the defects on the transmission function for a given defect
density by statistical analysis. We show that the system is in the regime of
strong localization (i.e. Anderson localization). In the limit of large
disorder the conductance scales exponentially with the number of defects. This
allows us to extract the localization length. Furthermore, we study in a
systematic and comprehensive way, how the conductance, the conductance
distribution, and the localization length depend on defect probability, CNT
diameter, and temperature.
