Surface polaron in the vicinity of two orthogonal surfaces.

Abstract

When a slow electron is in the vicinity of a corner made of two orthogonal ionic surfaces such as LiF, it interacts with the surfaces in two forms, one representing the ionic polarization and the other representing electronic polarization. The comparison between the binding energy of the system with the related surface polarization quanta indicates that the latter takes the static image-potential form and the former creates a surface polaron in the vicinity of the corner. The coupling constant between the electron and surface phonon in LiF is about 7 and, therefore, in the limit of small total momentum, we can adopt the simple Tomonaga approximation for the wave function to calculate the binding energy and effective mass of the system. The result shows the presence of the second surface increasing both the binding energy and effective mass of the surface polaron.