Starting from selection rules for intershell tunneling in double-walled nanotubes with commensurate ($c$-DWNTs) and incommensurate ($i$-DWNTs) shells, we show that for $i$-DWNTs the coupling is negligible between lowest energy subbands, but it becomes important as the higher subbands become populated. In turn the elastic mean-free path of $i$-DWNTs is reduced for increasing energy, with additional suppression at subband onsets and crossings. At low energies, a Luttinger liquid theory for DWNTs with metallic shells is derived. Interaction effects are more pronounced in $i$-DWNTs than in $c$-DWNTs.

• Received 6 April 2005

DOI:https://doi.org/10.1103/PhysRevLett.95.266802