Multislice simulation of TEM images
LE3 .A278 2012
2012
Robertson, Michael
Acadia University
Bachelor of Science
Honours
Physics
Numeric simulation of physical processes can be a highly useful tool that enables experimenters to investigate situations and processes that would otherwise be difficult or impossible to examine in the lab. Applied to the subject of electron diffraction and the simulation of transmission electron microscope images, numerical methods enable experimenters to examine the effects of defects in materials and help to identify imaging artifacts [4]. In this thesis, two important aspects of image simulation, specimen potential and calcu-lation methodology have been investigated. An alternative and more accurate method of calculating the specimen potential is investigated and two variants on the multislice method (originally developed by Cowley and Moodie [2]) for transmission electron microscope im-age simulation are presented and analyzed. Additionally, a brief overview of the effects of super-cell size on real space and reciprocal space images is given. It is shown that the standard method of calculating the specimen potential gives results consistent with the new potential calculation method when the simulation slice thickness is made small. This observation indicates that Kirkland’s minimum slice thickness hypothesis may be in error [4]. In addition, it is demonstrated that the multislice method is not conver-gent on a direct numeric integration of the Schr¨odinger equation and that the dimensions of the simulated super cell contribute significantly to image formation.
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https://scholar.acadiau.ca/islandora/object/theses:896