Silicon adsorption in defective carbon nanotubes: a first principles study

The electronic and structural properties of an (8, 0) single-walled carbon nanotube (SWNT) with a single vacancy and interacting with a Si atom are studied using first principles calculations based on the density-functional theory. Initially, the Si atom is positioned in the site above the vacancy, with its position fixed until the nanotube geometry is fully relaxed. After that, the Si atom approaches the tube and it is shown that one C atom is displaced outwards forming a bump. The final configuration, as well as each step of the process, is studied in detail and the resulting band structures and the total charge densities are systematically analysed.