Programable Beam Control for Electron Energy-Loss Spectroscopy and Ptychography

Area of Science:

• Materials Science
• Physics
• Analytical Chemistry

Background:

• Scanning transmission electron microscopy (STEM) is crucial for materials characterization.
• Scan-induced artifacts and dose limitations affect high-resolution imaging and spectroscopy.
• Non-raster scanning trajectories offer potential solutions for improved data acquisition.

Purpose of the Study:

• To systematically benchmark non-raster electron-beam scanning trajectories.
• To evaluate their impact on electron energy-loss spectroscopy (EELS) and ptychography.
• To provide guidelines for implementing advanced scanning strategies in 4D-STEM.

Main Methods:

• Comparison of raster, spiral, and multi-pass sequential scan patterns.
• Analysis of spatial resolution, spectral fidelity, and artifact suppression.
• Application to DyScO3 perovskite for EELS and ptychography, and BTO thin films under cryogenic conditions.

Main Results:

• Ptychographic reconstructions achieved atomic resolution and were robust to probe jumps.
• Atomic-resolution EELS maps exhibited sensitivity to probe motion, with non-uniform contrast from non-raster scans.
• Spiral scanning under cryogenic conditions improved dose uniformity and reduced drift artifacts in BTO films.

Conclusions:

• Non-raster scan strategies offer benefits for dose efficiency and artifact mitigation in 4D-STEM.
• Ptychography demonstrates inherent resilience to trajectory-induced artifacts.
• EELS requires optimized non-raster trajectories to maintain spectral fidelity and elemental contrast.