'Digital' Electron Diffraction - Seeing the Whole Picture

TL;DR

This paper introduces a computer-controlled technique for electron diffraction that captures a wide angular range of data simultaneously, improving analysis of thin materials and larger lattice structures.

Contribution

A novel computer-controlled method that overcomes previous angular limitations in electron diffraction, enabling comprehensive data collection from small focused beams.

Findings

Enhanced diffraction data over large angular ranges

Improved interpretation and applicability for thin and large-lattice materials

Significant increase in information content from electron diffraction patterns

Abstract

The advantages of convergent beam electron diffraction for symmetry determination at the scale of a few nm are well known. In practice, the approach is often limited due to the restriction on the angular range of the electron beam imposed by the small Bragg angle for high energy electron diffraction, i.e. a large convergence angle of the incident beam results in overlapping information in the diffraction pattern. Techniques have been generally available since the 1980s which overcome this restriction for individual diffracted beams, by making a compromise between illuminated area and beam convergence. Here, we describe a simple technique which overcomes all of these problems using computer control, giving electron diffraction data over a large angular range for many diffracted beams from the volume given by a focused electron beam (typically a few nm or less). The increase in the amount of information significantly improves ease of interpretation and widens the applicability of the technique, particularly for thin materials or those with larger lattice parameters.