Diffuse Streak Diffraction Patterns from Single Crystals I. General Discussion and Aspects of Electron Diffraction Diffuse Streak Patterns

TLDR

Diffuse streak patterns from single crystals, recently observed in electron diffraction, correspond to non‑radial streaks seen in X‑ray diffraction and can be described by a parallel‑wall distribution of intensity along low‑index reciprocal lattice planes. The study aims to identify these streak patterns, relate them to X‑ray counterparts, and suggest that a linear‑chain scatterer model can be applied to other crystal systems. Evidence supporting this description is presented from electron diffraction data on silicon, germanium, and aluminium. Illustrations of the patterns in gold, iron, sodium and potassium chlorides, and barium titanate, together with the demonstration that a linear‑chain scatterer model reproduces the characteristic streak features of diamond and simple face‑centred cubic structures, confirm the model’s validity.

Abstract

Diffuse streak patterns from single crystals which have become to be noticed very recently in electron diffraction are identified with the “non-radial” streak patterns in X-ray diffraction and their description in terms of parallel wall distribution of intensity weight along low index reciprocal net planes is discussed. Evidences for the description in electron diffraction patterns from silicon, germanium, aluminium. gold, iron, sodium and potassium chlorides and barium titanate are illustrated. An assumption of linear chain scatterers consisting of a small number of nearest neighbour atoms shifted from their regular positions is shown to be able to reproduce the characteristic features of the streak patterns from diamond structure and simple face centred cubic structure. Applicability of similar assumptions to the other cases is suggested.