Insight into structures and electronic states of connected (n/n−1, 0) carbon nanotubes: Implications from a SCC-DFTB algorithm

Abstract

A self-consistent density functional tight binding (SCC-DFTB) algorithm is performed to investigate geometries and electronical structures of bamboo-like (n/n-1,0) carbon nanotube through connecting (n-1,0) and (n,0) zigzag carbon nanotube. The connection tubes are characterized by packing geometries, bond length, intrinsic energy, energy gap, chemical potential, Mulliken populations, charge density differences, and molecular orbitals at HOMO and LUMO energy levels. These simulation results present significant differences compared to straight carbon nanotubes. Charge density differences suggest the bonding changes among the carbon atoms of the tubes having different diameters. The charge amount gained or lost can occur among the atoms at the junction in the small diameter tubes, while the gained or lost charge mainly occurs on the eight carbon atoms in the "heart" octagon in the large diameter ones. There are significant differences in HOMOs and LUMOs in the tubes with small chiral indexes. The HOMOs of the tubes with large chiral index are different from the LUMOs at the junction. The present simulations provide helpful support for developing novel molecular devices, which may be used in the field of light, corrosion resistance, and efficient microwave absorbents.

Graphical Abstract

Self-consistent density functional tight binding (SCC-DFTB) algorithm is performed to investigate the connection of (n, 0) and (n−1, 0) carbon nanotubes.