DYNAMICAL IMAGE FORCES IN THREE-LAYER SYSTEMS AND FIELD EMISSION

The dynamical image forces are calculated in the infinite barrier model with specular reflection at the interfaces for a non-relativistic charge moving in the core of the three-layer sandwich. Spatial disperison of the cover layer dielectric functions and the temporaldispersion of dielectric functions for all three layers are taken into account. Dynamical corrections to the conventional image forces make it possible to explain large field deviations from the Fowler-Nordheim law in the cold emission from metals and the photo-assisted electron tunneling in MOS structures.