The effect of the presence of extended vacancy pairs upon the conductance of armchair carbon nanotubes was investigated using a conventional π-electron tight-binding model. It was found that the conductance in the linear band region around the Fermi energy exhibited resonance peaks and dips which could be understood as being double-barrier scattering resonances and Fano anti-resonances. Their number depended upon the longitudinal inter-vacancy separation. For a given longitudinal inter-vacancy separation, only two 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