SPATIAL-RESOLUTION IN ELECTRON-ENERGY LOSS SPECTROSCOPY

Within the semi-classical theory, energy loss scattering may be calculated in an electrostatic limit. The range of interaction is then dominated by the response of the probed system and not by the Coulomb potential of the swift electron. General quantum mechanical considerations lead to the conclusion that the semi-classical approach is very good for high-energy electron scattering, and provide a good framework for evaluation of scattering using small probes. Excitation of a localized electron state, or an electron-hole pair, is highly modified by the presence of dielectric screening within a solid. This screening may be visualized as a response field within the bulk, and is closely related to the charge density wake which trials the swift electron. The spatial resolution for this situation is less than 0.5 nm.