Numerical study of impurity scattering in carbon nanotubes

The transmission and reflection coefficients of a carbon nanotube with a scatterer are calculated in a tight-binding model. The result obtained in a k . p scheme is shown to be essentially valid, including the complete absence of back scattering for scatterers with range larger than the lattice constant, unless the strength of the potential becomes comparable to the band width. When the potential strength is comparable to the band width, a resonant enhancement of back scattering appears and the result becomes completely different from that in the k . p scheme.