Single-walled carbon nanotubes could function as nanoscale reaction chambers for growing smaller nanotubes within the host tube from encapsulated fullerenes by annealing. The diameter of the host outer tube restricted the diameter of the inner tube due to van der Waals interactions but not its chirality. It was possible that inner tubes with different chiralities started to grow in different places at the same time. A straight junction occurred at the connection of the two tubes; bamboo defects. It was shown that localized states appeared in the calculated density of states associated with these defects, some of them close to the Fermi level. A detailed theoretical study was made of ballistic transport through double-walled tubes where the inner shell contained bamboo defects. It was found that the presence of such defects should be possible to detect using electronic-transport measurements. The number of bamboo defects per unit length could be deduced from the structure of the resonances appearing in the transmission coefficient.

Characteristics of Bamboo Defects in Peapod-Grown Double-Walled Carbon Nanotubes. V.Zólyomi, J.Koltai, D.Visontai, L.Oroszlány, A.Rusznyák, I.László, J.Kürti: Physical Review B, 2010, 82[19], 195423