Electron energy-loss near-edge structure studies at the atomic level: reliability of the spatial difference technique

The spatial difference technique was applied to determine the interface-specific components of electron energy-loss near-edge structures and the results are in good agreement to those obtained by atomic column resolved measurements averaged over one atomic layer. In previous studies an experimental set-up had been chosen where the scanning areas, which are used to measure electron energy-loss spectra, were symmetrical in respect to the location of the investigated interfaces. In the present study, an asymmetric setting of the scanning areas was applied, which allows the interfacial signals to be determined directly. Comparing the results of the different measurements shows that the spatial difference technique is valid and can be used to obtain information about the electronic structure of interfaces where single atomic column resolved measurements are not yet possible.