Surface excitation in a semi-classical approach

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Accurate characterization of electron-matter interactions is crucial for surface analysis.
• Existing models may not fully capture surface excitation phenomena.
• Understanding electron inelastic scattering is key to interpreting spectroscopic data.

Purpose of the Study:

• To develop a detailed semi-classical theoretical model for surface excitation.
• To describe the electron differential inverse inelastic mean free path (DIIMFP) in the surface region.
• To quantitatively analyze electron-beam interactions using reflection electron energy loss spectroscopy (REELS).

Main Methods:

• Formulation of a theoretical model in cylindrical coordinates for momentum transfer.
• Derivation of surface dielectric function from bulk dielectric properties.
• Integration of electron inelastic scattering model into reverse Monte Carlo simulations.
• Acquisition and analysis of REELS spectra for lead (Pb) at various electron incident energies.

Main Results:

• The model explicitly incorporates surface plasmon dispersion.
• A depth-dependent surface dielectric function was derived.
• REELS analysis revealed a pronounced bulk plasmon in lead at 13 eV with high intensity.
• Experimental results showed excellent agreement with theoretical calculations.

Conclusions:

• The developed theoretical model provides a robust framework for surface excitation analysis.
• The study successfully extracted the bulk dielectric function of lead.
• The findings enhance the quantitative analysis capabilities of REELS for material characterization.