Strong effect of chirality on doped single walled carbon nanotubes

Abstract

Carbon nanotubes (CNTs) are one of the important 'tailor made' materials, in the sense that their properties can be tuned in desired ways. A lot of research work is in progress to investigate the various properties of CNTs to exploit them for possible technological applications. It has been observed that impurity doping largely affects the band structure of CNTs, giving rise to novel phenomena. In this work, we have investigated the effect of curvature on the donor binding energies of both chiral and achiral CNTs with n−m=1, 2 such as (5, 4), (6, 5), (5, 3) and (6, 4) with diameter ranging from 0.5 to 1.3 nm. Band curvature has been included through the corresponding effective mass derived from a suitable energy dispersion relation, and binding energies are calculated as a function of impurity concentration. The results show that binding energy decreases as the curvature and impurity concentration increase for all types of tubes, but the rate of decrease is very high for chiral tubes, indicating the strong effect of chirality on doped single walled CNTs.