Defect modeling in HRTEM image simulation

Abstract

One practical problem in High Resolution Transmission Electron Microscopy (HRTEM) image simulation is the creation of atomistic models of defect structures. The ideal crystal structures are readily represented by a relatively small number of “basis” atoms and the crystallographic space group. On the other hand, the specification of a grain boundary between two crystals requires the atomic location of possibly thousands of atoms, and a HRTEM simulation program will need all this information before a calculation can be carried out. Users comfortable with writing computer code will write a computer program to generate the hundreds or thousands of atomistic locations, while others may be forced to enter the data by hand or search around for a ready made program that can generate the required data To the authors knowledge, no such suitable program is readily available. There are existing programs that will generate geometric interface models, but these programs were designed to create input to atomistic relaxation calculations, not as generalized tools for creating defect structures.