Practical aspects of electron energy-loss spectroscopy (EELS) calculations using FEFF8

Area of Science:

• Computational Physics
• Materials Science
• Spectroscopy

Background:

• Electron energy-loss spectroscopy (EELS) is a powerful technique for probing electronic structure.
• Accurate theoretical simulations are crucial for interpreting complex EELS spectra, especially core-loss regions.
• The FEFF8 code offers a sophisticated approach based on real-space multiple scattering theory.

Purpose of the Study:

• To present the application of the ab initio FEFF8 program for calculating electron energy-loss spectroscopy (EELS) core-loss spectra.
• To address practical considerations for accurate EELS simulations using FEFF8.
• To demonstrate the interpretation of EELS spectra in terms of electronic structure and local projected density of states (LDOS).

Main Methods:

• Utilizing the FEFF8 code, which employs a self-consistent, real-space multiple scattering formalism.
• Focusing on the construction of well-converged potentials and the treatment of core-hole effects.
• Incorporating experimental conditions such as sample orientation and finite temperature (Debye-Waller factors).

Main Results:

• Demonstrated the capability of FEFF8 to simulate core-loss EELS spectra with attention to practical simulation parameters.
• Illustrated the influence of experimental factors on spectral features.
• Showcased the analysis of ionization edges in Gallium Nitride (GaN) as a case study.

Conclusions:

• FEFF8 is a valuable tool for ab initio EELS core-loss spectral calculations.
• Careful consideration of computational parameters and experimental conditions is essential for reliable spectral interpretation.
• The code facilitates the connection between experimental spectra and fundamental electronic structure properties.