High-resolution transmission electron microscopy image simulation of screw dislocation core structures in body centered cubic metals
✍ Scribed by Y. Kamimura; K. Edagawa; M. Noda; K. Suzuki; S. Takeuchi
- Publisher
- Elsevier Science
- Year
- 2004
- Tongue
- English
- Weight
- 221 KB
- Volume
- 387-389
- Category
- Article
- ISSN
- 0921-5093
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✦ Synopsis
High-resolution transmission electron microscopy (HRTEM) images are simulated for the core structures of 1/2[111] screw dislocations in body centered cubic (bcc) metals to examine the possibility of determining the core structure experimentally by HRTEM. Two types of cores are studied: a polarized core and an isotropic one. For the model crystals containing the screw dislocations with the two types of cores, HRTEM images are calculated by a multi-slice method with the incident beam parallel to the [1 1 0] direction that is perpendicular to the direction of the dislocation line. A qualitative difference between the images of the two types of cores is detected; for the isotropic core the image always possesses the two-fold symmetry, irrespective of the defocus value, while for the polarized core it does not. This fact suggests that HRTEM experiments with the incident beam parallel to the [1 1 0] direction can distinguish between the two types of core.