Image states on Pb/Ge(111) observed through electron scattering

Resonant inelastic electron scattering is a new method that allows to detect image resonances with an energy resolution that makes line-shape analysis possible at an energy far above the vacuum level. For a better understanding of image states on Pb/Ge(111) and of the scattering mechanism, the two symmetry directions of the surface Γ̄M̄ and Γ̄K̄, and the dependence of the image resonances on the surface phases, the sample doping and the Pb coverage have been investigated. The maximum intensity of the image resonances is found for coverages ≥1 ML.