Comparative study of the electron–electron interactions on optoelectronic properties of carbon nanotube within orthogonal and nonorthogonal tight-binding model

Abstract

We investigate the electron–electron (e–e) interactions effect on the optoelectronic properties of single-walled carbon nanotubes (SWCNTs). We study theoretically the effect of e–e interactions on the optoelectronic properties of zigzag carbon nanotubes and obtain some useful expressions for the band structure and optical absorption of nanotubes for the first nearest-neighbor (1NN) and second nearest-neighbor (2NN) approximation in tight-binding (TB) model. Our computational approach is based on combination of the orthogonal (o-TB) and nonorthogonal (n-TB) tight-binding method with Hubbard model for zigzag SWCNTs. In nonorthogonal tight-binding model we consider the effect of orbital overlap on optoelectronic properties of nanotubes. We also obtain the optical absorption spectrum of zigzag SWCNTs under e–e interactions effect with considering orthogonal and nonorthogonal tight-binding method for 1NN and 2NN approximation. We investigate optical absorption for the incident light polarized parallel to the tube axis and obtain all allowed optical transitions. Our results show some variations in the band structure and optical absorption spectrum of nanotubes under e–e interactions effect when we use orthogonal tight-binding model compare with nonorthogonal tight-binding model.