Electronic structure of carbon nanotubes with chiral symmetry

The sigma+pi electron densities of states of chiral carbon nanotubes are computed with a tight-binding Hamiltonian. Our calculations show that the electronic structures of carbon nanotubes with chiral symmetry are similar to the zigzag and armchair ones. The implications of these results on the characterization of single-wall nanotube ropes using resonant Raman experiments are discussed.