Eur. Phys. J. B 61, 433-439 (2008)
https://doi.org/10.1140/epjb/e2008-00104-3

Structural dependence of exciton in carbon nanotubes

Group of Computational Condensed Matter Physics, National Laboratory of Solid State Microstructures and Dept. of Physics, Nanjing University, Nanjing, 210093, P.R. China

Corresponding author: ^a jdong@nju.edu.cn

Received: 20 August 2007
Revised: 31 December 2007
Published online: 13 March 2008

Abstract

The binding energies and sizes of excitons, and energy splitting of the bright-dark excitons in single-walled carbon nanotubes have been calculated using the nonorthogonal tight-binding model, supplemented by the long-range Coulomb interaction. It is found that the binding energies and the sizes of excitons not only depend on tube's diameter d, but also its chirality. However, the splitting of the bright-dark excitons mostly depends on 1/d². Our obtained results show that the curvature effect is very important for the exciton excitations in the SWNTs, especially in the smaller diameter ones.