Effect of intertube coupling on the electronic structure of carbon nanotube ropes

We calculate the structural and electronic properties of an ordered “bundle” of (10,10) carbon nanotubes. Our results indicate that intertube coupling causes an additional band dispersion of (Formula presented) and opens up a pseudogap of the same magnitude at (Formula presented) Soft librations at (Formula presented) are predicted to occur below the orientational melting temperature which marks the onset of tube rotations about their axis. Whereas the density of states near (Formula presented) increases by 7% due to intertube coupling and by one order of magnitude due to K doping in (Formula presented) these states do not couple to tube librations.