Electronic and structural properties of silicon-doped carbon nanotubes - art. no. 085413

Predictions of the electronic and structural properties of silicon substitu tional doping in carbon nanotubes are presented using first-principles calc ulations based on the density-functional theory. A large outward displaceme nt of the Si atom and its nearest-neighbor carbon atoms is observed. For th e two tubes studied [metallic (6,6) and semiconducting ( 10,0)] the formati on energies of the substitutional defects are obtained around 3.1 eV/atom. In the doped metallic nanotube case a resonant state appears about 0.7 eV a bove the Fermi level, whereas for the semiconductor tube, the silicon intro duces an empty level at approximately 0.6 eV above the top of the valence b and.