High-resolution angle-resolved photoemission studies of the surface states on Al(111) and Al(001)

High-resolution angle-resolved photoemission has been used to study Al(111) and Al(001). Two new surface states at {Γ}{} and K{} of Al(111) were observed and characterized. Their energy positions are in good accord with recent self-consistent calculations. The state at {Γ}{} is observed over a narrow range of photon energies near h{ν}=53 eV. A simple model is presented which explains this observation and gives a rough estimate of the decay length of the surface state into the bulk. Further studies of the evolution of the peak width as a function of parallel momentum for the {Γ}{} surface state on both surfaces indicates the presence of a new broadening mechanism. Interactions of the initial and final states with the nearby bulk continuum is suggested.