| Abstract Scope |
Four-dimensional scanning transmission electron microscopy (4D-STEM) enables quantitative mapping of atomic structure, strain, and electromagnetic fields. This talk presents workflows for ePDF reconstruction and field mapping, examining how convergence angle, detector sampling, angular range, dose, precession, thickness, and multiple scattering affect accuracy. Applications include nanometer-resolved ePDF mapping of short- and medium-range order in metallic glasses [1,2]. Diffraction-ring distortion in the same datasets also enables strain mapping, revealing shear-band-associated heterogeneity and linking atomic order, residual strain, and structure–property relationships [3,4]. The broader applicability of 4D-STEM is further demonstrated through electric-field mapping of grain-boundary space-charge layers in polycrystalline electroceramics.
[1] S. Kang et al., Ultramicroscopy 281, 114295 (2026).
[2] S. Kang et al., Acta Materialia 269, 119495 (2024).
[3] S. Kang et al., Advanced Materials 202212086 (2023).
[4] S. Kang et al., Nature Communications 16, 1305 (2025). |