The effects of wave-function dimensionality and inelastic localization on ALCHEMI (Atom Location by Channeling-Enhanced Microanalysis) are studied. The original ALCHEMI equations are shown to hold for the case of partially delocalized excitations, provided that the thickness-averaged dynamical electron wavefield varies slowly over the localization volume. Experimental and theoretical comparisons of electron channeling in GaAs show that characteristic X-ray emission intensities in the axial orientation are more sensitive to variations in X-ray energy than are those in the planar (systematics) geometry. The effects of variations in localization are elucidated in a two-beam analysis, and methods for extending ALCHEMI to low-energy X-ray emission are discussed.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics