Electronic structure of cross-linked carbon nanotubes doped with alkali metals

Based upon ab initio density functional theory calculations, it has been predicted that bundles of small zigzag single walled carbon nanotubes can undergo spontaneous cross linking to form 2-dimensional layered structures. Analogous to graphite, these layered structures should provide a framework that allows intercalation of chemical species. Using density functional theory, we explore the possible structures of alkali metal intercalated cross-linked (5,0) nanotubes and calculate the electronic properties of these materials. We have found that the intercalated materials undergo substantial lattice expansion and that the metal atoms are largely ionized. The cross-linked (5,0) nanotube material and the alkali metal intercalation compounds are predicted to be metallic representing a substantial change in electronic properties relative to the semiconducting cylindrical (5,0) zigzag nanotubes.