Exciton States and Linear Optical Spectra of Semiconducting Carbon Nanotubes under Uniaxial Strain

Considering the exciton effect, the linear optical spectra of semiconducting single-walled carbon nanotubes (SWNTs) under uniaxial strain are theoretically studied by using the standard formulae of Orr and Ward [Mol. Phys. 20(1971)513]. It is found that due to the wrapping effect existing in the semiconducting zigzag tubes, the excitation energies of the linear optical spectra show two different kinds of variations with increasing uniaxial strain, among which one decreases such as tube (11,0), and the other increases firstly and then decreases such as tube (10,0). These variations of the linear optical spectra are consistent with the changes of the exciton binding energies or the (quasi)continuum edge of these SWNTs calculated in our previous work, which can be used as a supplemented tool to detect the deformation degree of an SWNT under uniaxial strain. (condensed matter: electronicstructure, electrical, magnetic, and opticalproperties)