  Scanning transmission electron microscopy (STEM) has advanced rapidly in the
last decade thanks to the ability to correct the major aberrations of the probe
forming lens. Now atomic-sized beams are routine, even at accelerating voltages
as low as 40 kV, allowing knock-on damage to be minimized in beam sensitive
materials. The aberration-corrected probes can contain sufficient current for
high quality, simultaneous, imaging and analysis in multiple modes. Atomic
positions can be mapped with picometer precision, revealing ferroelectric
domain structures, composition can be mapped by energy dispersive X-ray
spectroscopy (EDX) and electron energy loss spectroscopy (EELS) and charge
transfer can be tracked unit cell by unit cell using the EELS fine structure.
Furthermore, dynamics of point defects can be investigated through rapid
acquisition of multiple image scans. Today STEM has become an indispensable
tool for analytical science at the atomic level, providing a whole new level of
insights into the complex interplays that control materials properties.
