Work function calculation of solid solution alloys using the image force model

The electronic work function of polycrystalline solid solution alloys is being analytically calculated using three different approaches. All approaches are derived by assuming that the alloys are in equilibrium and therefore surface segregation causes a difference between the surface composition and the bulk composition. An approach based on the image force, an approach based on the dipole layer formed due to electronegativity differences, and a simple surface concentration approach are compared to published experimental results. The image force model has a good agreement with the experiments, while the dipole-layer approach has a poor agreement, challenging the conventional concept of the double layer.