4D imaging of transient structures and morphologies in ultrafast electron microscopy

Area of Science:

• Materials Science
• Physics
• Chemistry

Background:

• Electron microscopy offers atomic-scale resolution for 2D and 3D imaging.
• Studying dynamic processes at the nanoscale requires advanced imaging techniques.

Purpose of the Study:

• To introduce and demonstrate 4D imaging capabilities in ultrafast electron microscopy (UEM).
• To enable in situ spatiotemporal resolution for studying fleeting structures and morphologies.

Main Methods:

• Utilizing ultrafast electron microscopy (UEM) for 4D imaging.
• Controlling pulse separation for temporal cooling and capturing selected-area-image dynamics with pixel resolution.

Main Results:

• Observed atomic structural expansion, nonthermal lattice temperature, and ultrafast transients in gold under thermal stress.
• Detected coherent structural transients and measured the nanoscale resonance period in graphite, linked to Young's elastic modulus.

Conclusions:

• UEM provides a powerful tool for real-space imaging of dynamic processes at the atomic scale.
• The demonstrated applications highlight UEM's potential for investigating transient material behaviors.