Surface excitations in electron spectroscopy. Part I: dielectric formalism and Monte Carlo algorithm

Area of Science:

• Condensed Matter Physics
• Surface Science
• Computational Physics

Background:

• Understanding energy loss mechanisms of charged particles interacting with surfaces is fundamental in various surface analysis techniques.
• Existing models often rely on simplifications that can significantly impact the accuracy of simulations.
• Accurate theoretical descriptions are needed for reliable interpretation of experimental data in surface electron spectroscopy.

Purpose of the Study:

• To derive a general theory for the energy losses of charged non-relativistic projectiles crossing a planar interface.
• To investigate the impact of common simplifications on key parameters like differential inelastic inverse mean free path (DIIMFP) and stopping power.
• To implement the derived theory into a Monte Carlo algorithm for electron transport simulations.

Main Methods:

• Derivation of the energy loss theory based on Maxwell equations, detailing physical assumptions.
• Examination of charged projectile dynamics, including induced surface charge, DIIMFP, and stopping power.
• Implementation of the model in a Monte Carlo algorithm for simulating electron transport.

Main Results:

• The developed model is general and can reproduce common surface excitation models.
• Investigated simplifications can lead to significant discrepancies (up to 100%) in DIIMFP peak characteristics.
• Simulated reflection electron energy loss spectra show good agreement with experimental data on an absolute scale.

Conclusions:

• The derived theory provides a robust framework for describing charged particle energy loss at interfaces.
• The study highlights the importance of avoiding common simplifications for accurate DIIMFP and stopping power calculations.
• The Monte Carlo implementation enables reliable simulations for surface electron spectroscopy, validating the model against experimental results.