Transition from one-dimensional to three-dimensional behavior induced by lithium doping in single wall carbon nanotubes

The electronic properties of Li doped single-wall carbon nanotubes were studied by high-resolution photoemission spectroscopy. Upon Li intercalation, the limited displacement of the Fermi level agrees with a partial charge transfer of the Li2s electron to the C2p-pi* states. The increase of the density of states near the Fermi level with Li concentration suggests a transition from the one-dimensional Tomonaga-Luttinger liquid behavior, observed in the pristine nanotubes, to three-dimensional transport properties in the doped sample. The increased spectral weight near the Fermi level can be also partly ascribed to the formation of new states in the conduction band due to the hybridization between Li and C.