First-principles dynamic simulations of field emission from carbon nanotubes on gold substrate

In order to investigate the usability of carbon nanotubes as electron-beam sources, we carry out dynamic simulations of the field emission of open-tip armchair single-wall carbon nanotubes in a fully first-principles manner. By including a metallic substrate in the structure, the charge transfer from the substrate to the carbon nanotubes under external electric fields is self-consistently taken into account and the description of the potential becomes more realistic. It is found that s-like pi states near the Fermi level make a major contribution to the emission current. The emission patterns of the s-like pi states take the shape of a small spot at the center and a ring around it.