Using Scanning Transmission Electron Microscopy (STEM) to Study Oxides and Future Outlook on 4D-STEM

Oxides can host a variety of physical properties including metallicity, ferroelectricity, piezoelectricity and superconductivity. As lattice structures or defects at nanoscale are responsible for exhibiting certain properties, scanning transmission electron microscopy becomes an important characterization tool for oxides. Here we first introduce what oxides are, and proceed to show several examples where microscopy can aid our understanding of oxides. Moreover, with the development of electron microscopy detectors, the concept of four-dimensional scanning transmission electron microscopy will be briefly introduced. Examples using this method and its future outlook will be discussed further.