Modulation of intertube band dispersion relation of carbon nanotube bundles by symmetry and intertube wave function coupling

Based on density functional theory with a local density approximation and the simple tight-binding approximation, we investigated an electronic structure of carbon nanotube bundles in terms of mutual nanotube arrangement. The dispersion relation near the Fermi level along the intertube direction was found to be sensitive to the nanotube species and their mutual orientation within the bundles. Nanotube bundles with three-fold symmetry exhibited a substantial orientation dependence in the band dispersion relation along the intertube direction. The tight-binding calculation and wave function analysis revealed that this orientation dependence arises from the intertube wave function coupling whether a node exists between nanotubes.

Automated summary

In this study, the electronic structure of carbon nanotube bundles was investigated using density functional theory and a simple tight-binding approximation. The research found that the band dispersion relation near the Fermi level along the intertube direction is sensitive to the nanotube species and their mutual orientation within the bundles, especially in cases of three-fold symmetry. The tight-binding calculation and wave function analysis revealed that this orientation dependence is due to intertube wave function coupling, regardless of the existence of a node between nanotubes.