Simulation of probe position-dependent electron energy-loss fine structure

Area of Science:

• * Materials Science
• * Condensed Matter Physics
• * Electron Microscopy

Background:

• * Electron energy-loss near-edge structure (EELS) provides insights into local electronic structure.
• * Traditional EELS calculations often neglect electron beam dynamics.
• * Understanding probe position dependence is crucial for accurate nanoscale analysis.

Purpose of the Study:

• * To develop a theoretical framework for probe-position-dependent EELS.
• * To accurately model the influence of electron beam diffraction and focusing.
• * To differentiate electronic structure variations from beam effects in EELS.

Main Methods:

• * Combining density functional theory (DFT) with dynamical scattering theory (DST).
• * Calculating EELS spectra considering probe position and size.
• * Comparing results with simpler theoretical approaches.

Main Results:

• * The proposed framework accurately captures the evolution of EELS with probe position.
• * Simpler methods fail to account for essential beam physics.
• * The dependence of EELS on probe size is systematically investigated.

Conclusions:

• * The combined DFT-DST framework is essential for accurate EELS interpretation.
• * This method allows for reliable analysis of local electronic structure.
• * It provides a robust tool for advanced scanning transmission electron microscopy studies.