Simulation of transmission electron microscopy diffraction patterns
LE3 .A278 2015
Bachelor of Science
Transmission electron microscopy (TEM) is the only instrument for studying the phys- ical, compositional, optical and electronic structure of materials at sub-nanometre length scales. However, TEM images and di raction patterns are often not easily interpretable and rigorous numerical simulation work is required to extract as much information as possible from the data. The goal of this project is to design and code a program that will, in the Bloch-wave formalism, calculate the Bloch-wave basis states, the atomic potential map, and the electron di raction pattern, for any crys- talline structure at any zone-axis orientation. The contribution of this work to the overall project has been the automated selection of di raction beams used to form the Bloch-wave basis states, as well as incorporating crystallographic transformations so that di raction patterns of 3D crystals from various coordinate systems can be projected onto a 2D Cartesian plane for calculation and viewing. In order to test the program, di raction patterns from arti cial test crystals with known solutions were compared to expected results. As well, application to ve real crystals: Au, Si, MnSi, Mn5Si3, Mn4Si7 will be presented. Furthermore, comparison to several experimental patterns of MnSi will be shown.
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