T. Fondén, S. Papadia, and M. Persson
J. Phys.: Cond.
Matt. 7, 2697 (1995)
We extend and detail a previously developed model for formation of electronic resonances at free-electron-like metal surfaces, in order to calculate scanning tunneling (ST) spectra. The effect of the tip is mimicked by inclusion of an external field, self-consistently, in a jellium description of the surface potential. The lattice-induced corrugation of the potential is included perturbatively via a pseudopotential. We compare our calculated ST spectra for Al(111) with experimental spectra for that surface and conclude that a peak occuring below the metal vacuum level is a ``crystal-derived'' resonance, in the sense that lattice effects are crucial for its manifestation.