The exit-wave power-cepstrum transform for scanning nanobeam electron diffraction: robust strain mapping at...

Area of Science:

• Materials Science
• Solid State Physics
• Electron Microscopy

Background:

• Scanning nanobeam electron diffraction (NBED) offers rapid, spatially resolved lattice structure mapping.
• Dynamical diffraction and sample mistilts complicate accurate quantification of NBED data.
• Robust data processing is essential for precise measurements in complex samples.

Purpose of the Study:

• To develop a robust data processing technique for accurate strain mapping using NBED.
• To address challenges posed by intensity variations and sample mistilts in NBED analysis.
• To enable precise lattice structure measurements under non-ideal conditions.

Main Methods:

• Introduction of the Exit Wave Power Cepstrum (EWPC) transform for NBED pattern analysis.
• Development of an analytical model to decouple lattice information from intensity variations.
• Application of EWPC for strain mapping in ferroelectric films and nanoparticle catalysts.

Main Results:

• The EWPC transform converts NBED patterns into real-space patterns with peaks indicating inter-atomic spacings.
• A simple analytical model effectively separates lattice information from tilt and thickness effects.
• Strain mapping demonstrated sub-picometer precision and sub-nanometer resolution in practical applications.

Conclusions:

• The EWPC transform provides a robust method for precise lattice structure and strain measurements using NBED.
• This technique overcomes limitations of traditional NBED analysis, particularly for complex and tilted samples.
• EWPC enables advanced materials characterization with high accuracy and resolution.