Linear optical properties of deformed carbon nanotubes

Optical absorptions of the deformed single-walled carbon nanotubes (SWNTs) have been studied by the pi-band tight-binding calculation, in which the matrix elements of the momentum operator are evaluated in an analytical way similar to the first-principles calculation. Our study shows that the linear optical properties of the deformed SWNTs are very sensitive to the kind of strains and the nanotube geometry (radius and chiral angle). It is also found that the absorption spectra of a deformed finite-length SWNT exhibit some new characters, e.g., many new peaks appear along with the original characteristic peaks. Based upon the obtained results, an effective experimental tool is proposed to easily measure the deformation degree of a deformed SWNT.