Symmetry effect on the conductance of two-defect carbon nanotubes

The transport property and related electronic structure of a single-walled armchair carbon nanotube with two substitutional defects are studied within the $\pi$-electron tight-binding model. It is found that the conductance and the local density of states are strongly dependent on the symmetry and relative distance of the two defects. The effects of defect strength and nanotube size on the conductance are also discussed.