Energetics and electronic structure of C70-peapods and one-dimensional chains of C70 -: art. no. 122

We report total-energy electronic structure calculations that provide the energetics of encapsulation of C-70 fullerenes in carbon nanotubes. The encapsulation processes for C-70 in tubes thicker than (17, 0) are all exothermic. We find that the lying arrangement is energetically favourable for the thin nanotubes, whereas the standing arrangement is favourable for thick nanotubes. To explore the stable molecular arrangements in the nanotubes, we further study the energetics and electronic structures of one-dimensional chains of C-70. It is found that the standing intermolecular arrangement is the most stable structure for the chain due to the large intermolecular interaction. The electronic structures of the chains strongly depend on the mutual orientation of adjacent molecules. We find flat dispersion bands around the Fermi level of the standing chains and a possibility of spin polarization on the one-dimensional chain of C-70.