title: Symmetry quantification and mapping using convergent beam electron diffraction.
abstract: We propose a new algorithm to quantify symmetry recorded in convergent beam electron diffraction (CBED) patterns and use it for symmetry mapping in materials applications. We evaluate the effectiveness of the profile R-factor (R(p)) and the normalized cross-correlation coefficient (γ) for quantifying the amount of symmetry in a CBED pattern. The symmetry quantification procedures are automated and the algorithm is implemented as a DM (Digital Micrograph(©)) script. Experimental and simulated CBED patterns recorded from a Si single crystal are used to calibrate the proposed algorithm for the symmetry quantification. The proposed algorithm is then applied to a Si sample with defects to test the sensitivity of symmetry quantification to defects. Using the mirror symmetry as an example, we demonstrate that the normalized cross-correlation coefficient provides an effective and robust measurement of the symmetry recorded in experimental CBED patterns.
authors.affiliation: Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Kyou-Hyun
authors.initials: KH
authors.lastname: Kim
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Zuo
mesh_terms: D000465:Algorithms; D003461:Crystallography / Q000379:methods*; D004583:Electrons; D014057:Tomography, X-Ray Computed / Q000379:methods*