Abstract
We investigate the conductance through a single impurity in the metallic zigzag carbon nanotube and find that it sensitively depends on the impurity strength and the bias voltage. The interplay between the current-carrying scattering states and the evanescent modes lead to rich phenomena including resonant backward scattering, perfect tunneling, and charge accumulations. In addition to the Friedel sum rule, we also find an exact relation between the conductance and the scattering phase. Finally, relevance of our findings to the realistic transport in carbon nanotubes is discussed. © 2009 American Institute of Physics.