Influence of atomic coordination environment on the elastic-delocalization-induced artifacts in atomic-resolution...

Area of Science:

• Materials Science
• Analytical Chemistry
• Physics

Background:

• Atomic-resolution elemental mapping techniques like EDS and EELS are crucial for materials characterization.
• Elastic electron delocalization can displace elemental signals, creating artifacts that may lead to structural misinterpretations.

Purpose of the Study:

• To systematically investigate how the atomic coordination environment influences electron delocalization distance.
• To provide a quantitative basis for identifying and interpreting imaging artifacts in atomic-scale elemental analysis.

Main Methods:

• Utilized a model structure of multi-element metal carbide (Mo1.33Er0.67Nb2AlC3) for systematic investigation.
• Performed model simulations based on experimentally observed artifacts to analyze delocalization distances.

Main Results:

• EELS signals are more localized for light elements; EDS signals are more localized for heavy elements.
• Delocalization distance increases with convergence semi-angle and sample thickness.
• Neighboring atom's atomic number has a negligible effect (<0.1 Å) on delocalization, while interatomic spacing variations cause non-monotonic changes within 20%.

Conclusions:

• Electron delocalization artifacts in EDS and EELS are influenced by element type, experimental parameters, and interatomic spacing.
• The negligible effect of neighboring atom type simplifies artifact interpretation.
• Findings contribute to more accurate atomic-scale structural analysis using electron microscopy techniques.