Applications and theoretical simulation of low-loss electron energy-loss spectra

Abstract

Spectrum imaging using the low-loss part of the electron energy-loss spectrum plays a role in developing the understanding of the optical response of nanostructured materials. Applications to metal nanoparticles and quantum wells are given here. However, the effects of delocalisation prevent the measurement of bandgaps in embedded quantum wells, when a standard scanning transmission electron microscope is used (i.e. one without monochromation or aberration correction). The complex nature of the low-loss spectrum means that interpreting the features in the spectra is greatly aided by ab initio calculations based on the density functional theory. Examples of full potential and pseudopotential calculations are presented here and their limitations are highlighted.