Quantitative Agreement between Electron-Optical Phase Images of WSe_{2} and Simulations Based on Electrostatic...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Quantitative analysis of electron-optical phase images often uses simulations.
• Independent atom approximation in simulations overestimates experimental phase shifts by ~10% due to neglecting bonding effects.

Purpose of the Study:

• To develop and validate a computational method for accurate electron phase analysis in materials.
• To improve the accuracy of simulated electron phase images by incorporating bonding effects.

Main Methods:

• Comparison of experimental and simulated phase images for few-layer WSe2.
• Utilized a combination of pseudopotentials and all-electron density functional theory (DFT) calculations.
• Accurate simulation of electron propagation through the sample.

Main Results:

• Achieved accurate mean electron phases and improved atomic-resolution spatial distribution of electron phase.
• Demonstrated a perfect contrast match between experimental and simulated atomic-resolution phase images for a known thickness sample.
• The developed method shows low computational cost.

Conclusions:

• A combination of pseudopotentials and all-electron DFT calculations accurately predicts electron phase shifts by including bonding effects.
• This approach is suitable for analyzing large electronic systems, including defects, substitutional atoms, and material interfaces.
• Enables more precise quantitative analysis of electron-holography data.