Local Semiconducting Transition in Armchair Carbon Nanotubes: The Effect of Periodic Bi-site Perturbation on Electronic and Transport Properties of Carbon Nanotubes

摘要

In carbon nanotubes, the most abundant defects, caused for example byirradiation or chemisorption treatments, are small perturbing clusters, i.e.bi-site defects, extending over both A and B sites. The relative positions ofthese perturbing clusters play a crucial role in determining the electronicproperties of carbon nanotubes. Using bandstructure and electronic transportcalculations, we find out that in the case of armchair metallic nanotubes aband gap opens up when the clusters fulfill a certain periodicity condition.This phenomenon might be used in future nanoelectronic devices in which certainregions of single metallic nanotubes could be turned to semiconducting ones.Although in this work we study specifically the effect of hydrogen adatomclusters, the phenomenon is general for different types of defects. Moreover,we study the influence of the length and randomness of the defected region onthe electron transport through it.