Dresden 2026 – wissenschaftliches Programm
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FM: Fachverband Funktionsmaterialien
FM 11: Poster Session Functional Materials
FM 11.15: Poster
Dienstag, 10. März 2026, 18:00–20:30, P4
Towards Quantification of Convergent Beam Electron Diffraction Patterns — •Jimmy Steinweh1, Daniel Wolf1, and Axel Lubk1, 2 — 1Leibniz Institute for Solid State and Materials Research, Dresden, Germany — 2Institute of Solid State and Materials Physics, TU Dresden, Germany
Convergent beam electron diffraction (CBED) is a transmission electron microscopy (TEM) method, that utilizes a convergent electron beam to investigate the symmetry of crystalline samples at the nanoscale. A method for quantifying discrete rotational and mirror symmetries in CBED patterns is presented, involving a quantification algorithm for both simulated and experimental CBED patterns. This approach is used to investigate the influence of probe shifts, beam tilts, and thermal lattice vibrations on the symmetry of simulated CBED patterns of silicon to identify crystal structure related asymmetries. It is found that for a semi-convergence angle of α = 1.7 mrad, the asymmetry introduced by probe shifts is barely detectable in simulations, whereas beam tilt effects are significant at beam tilt angles as low as 0.1 mrad. Consequently, precise alignment of the beam in zone axis is crucial. We find furthermore that consideration of lattice vibrations within the frozen lattice approximation also slightly breaks the symmetry and discuss the origin of this effect. These results aim to establish a foundation for further development of CBED as a quantitative tool for probing crystal symmetries at the nanoscale.
Keywords: Transmission electron microscopy; Convergent Beam Electron Diffraction