Observing Symmetry Breaks in CBED Patterns: Insights into Specimen Morphology

What is it about?

The article discusses the observation of symmetry breakages in the intensity distributions of near-zone-axis convergent-beam electron diffraction (CBED) patterns due to the specimen's morphology, which cannot be explained by the material's atomic structure. The study examines CBED patterns of an aluminium-copper-tin alloy containing voids many tens of nanometres in size within continuous single crystals of the aluminium host matrix. The article shows that it is possible to deduce nanoscale morphological information about the specimen using CBED patterns.

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Photo by The Creativv on Unsplash

Photo by The Creativv on Unsplash

Why is it important?

This research is important because it demonstrates the strong effects that the symmetry of the specimen morphology can have on the intensities in convergent-beam electron diffraction (CBED) patterns. It shows that it is possible to deduce nanoscale morphological information about the specimen in the direction of the electron beam, which is the elusive third dimension in transmission electron microscopy. This has potential applications in morphological contrast imaging in 4D scanning transmission electron microscopy, which is a major area of development in microscopy, crystallography, and diffraction physics. Key Takeaways: 1. The symmetry of the specimen morphology can have strong effects on the intensities in CBED patterns. 2. It is possible to deduce nanoscale morphological information about the specimen in the direction of the electron beam. 3. The study suggests that tilted near-zone orientations may enhance QCBED structure factor measurements in and around nanostructures.