Abstract
4D-STEM (four dimensional scanning transmission electron microscopy) is a powerful technique for analysis from which structural, physical, chemical information can be extracted. When it comes to 4D-STEM experiment, a converged electron beam is scanned across the 2D area of sample, and a pixelated detector records a 2D diffraction pattern at each scan position. Thus, the final datasets have four dimensions. This paper will cover material information that can be obtained through 4D STEM and summarize the current status and use of 4D-STEM studies including virtual imaging, phase retrieval (ptychography) and structural analysis of amorphous materials. The future perspective of 4D-STEM for new findings is also discussed.