Lawrence Berkeley National Laboratory

With the advent of electron-optical systems able to generate negative spherical aberration (usually called "Cs correctors"), it has now become feasible to zero-out objective lens Cs in the high-resolution transmission electron microscope. However, I show that - instead of tuning out spherical aberration completely - there is an optimum value for the residual Cs that maximizes information transfer to the best possible resolution and depends only on the information limit of the microscope.