The electronic structures of a clean (001) surface, of a stepped (001) surface and of an Al(001) surface with vacancies, were investigated via first-principles calculations in order to elucidate the emission mechanism of field-stimulated exo-electrons from Al tip surfaces. The results showed that vacancies at the (001) surface slightly increased the local density of states in the occupied states, and that monatomic steps significantly increased the local density of states at 0.36eV above the Fermi level in the unoccupied states. The local density of states peak position in the unoccupied states at the stepped surface was close to the trap level of field-stimulated exo-electrons measured in previous experiments. It was concluded that the monatomic steps at Al surfaces could play the role of exo-electron traps.

Computational Study of the Effect of Surface Defects and Steps on Field-Stimulated Exo-Electron Emission from Aluminium. T.Shiota, M.Morita, M.Umeno, N.Shima, M.Tagawa, N.Ohmae: Physical Review B, 2002, 65[16], 165430 (4pp)