Symmetry-selected electron energy loss scattering

Abstract

Equation in Born approximation were obtained by expanding the swift electron Coulomb interaction in a Fourier series and choosing one momentum transfer. However, this kind of method is not agreeable for scattering in STEM. Therefore for differential cross sections for EELS, well defined diffraction conditions are needed. In these conditions initial and final states of swift electron that have chosen symmetries are produced with respect to atom columns in a sample. The standard two beam theory for Bragg reflection for the [001] oriented diamond crystal is used.