Interplay between Structural and Electronic Properties of Carbon Nanotubes

A combination of ab initio Density Functional and parametrized Linear Combination of Atomic Orbitals calculations is used to describe the interplay between structural and electronic properties of single-wall, multi-wall, and bundled carbon nanotubes. The electronic structure of cylindrical single-and multi-wall tubes with an extremely inhomogeneous charge density is determined self-consistently using a new technique that discretizes the eigenvalue problem on a grid and yields simultaneously all occupied and unoccupied states. Comparison with parametrized calculations, which consider explicitly the atomic positions, proves that the essential features of the electronic structure in these systems can be obtained if the ionic background is approximated by infinitely thin structureless cylindrical walls. Consideration of the atomic positions is essential when describing the low-frequency twisting motion of individual tubes within a “rope” or a multi-wall nanotubes. It is shown that the weak, partly anisotropic inter-wall interaction may cause significant changes in the density of states near the Fermi level in these systems.