Using the extended Su-Schriffer-Heeger model in real space, the electronic structure and charge density of three systems, (9,0)-(8,0), (9,0)-(7,0) and (9,0)-(6,0) were calculated. This was achieved by introducing topological defects (5/7), (5/6/7) and (5/6/6/7) into the perfect hexagonal network of the zig-zag carbon nanotube configuration. The results for the various systems were compared. This showed that the various arrangements of pentagons and heptagons along the axis caused obvious differences in the electrical properties of the carbon nanotube.

Effects of Topological Defects on Carbon Nanotube. L.Zhang, H.Hu: Chinese Journal of Semiconductors, 2005, 26[10], 1959-62