Exciton distribution on single-walled carbon nanotube

In this paper we calculate the binding energy of an exciton using the tight-binding model and discuss the exciton distribution in detail. We analytically explain the dependence of the distribution direction of exciton on the chiral angle, and the distribution localization along the tube axis and oscillating along the tube circumference. The size of exciton is estimated to be slightly larger than the diameter of the nanotube and it shows two family patterns versus the inverse of tube diameter as similar as in the exciton binding energy