The influence upon the conductance of armchair C nanotubes due to the presence of extended vacancy pairs was investigated by using a conventional π-electron tight-binding model. It was found that the conductance in the linear band region around the Fermi energy contained resonance peaks and dips, which could be understood as double-barrier scattering resonances and Fano anti-resonances and whose number depended upon the longitudinal inter-vacancy separation. Furthermore, for a given longitudinal inter-vacancy separation, only 2 distinctly different conductance spectra appeared in this energy region as the second vacancy in the pair assumed all different lateral positions around the tube circumference. It was also found that the conductance could be very sensitive to minimal changes in the relative inter-vacancy positions.

Resonances and Rotation Symmetries in the Conductance of Armchair Carbon Nanotubes with Extended Defect Pairs. U.Lindefelt: Physical Review B, 2005, 72[15], 153405 (4pp)