Developing Machine Learning Driven 4D-STEM Techniques
Four-Dimensional Scanning Transmission Electron Microscopy (4D-STEM) is a technique in which an electron beam is scanned across the specimen while a diffraction pattern is recorded at each probe position. This approach provides an enormous amount of structural and electronic information beyond conventional TEM analysis, enabling precise characterization of crystal structure, strain, and electric field distributions at the nanometer scale.
The diffraction patterns obtained from 4D-STEM inherently reflect different crystal phases and symmetries. By quantitatively analyzing these patterns, it becomes possible to distinguish and map complex multi-phase materials as well as local structural variations. This capability is essential for studying phase transitions in thin films, functional materials, and advanced devices.