title: Spatial resolution and information transfer in scanning transmission electron microscopy.
abstract: The relation between image resolution and information transfer is explored. It is shown that the existence of higher frequency transfer in the image is just a necessary but not sufficient condition for the achievement of higher resolution. Adopting a two-point resolution criterion, we suggest that a 10% contrast level between two features in an image should be used as a practical definition of resolution. In the context of scanning transmission electron microscopy, it is shown that the channeling effect does not have a direct connection with image resolution because sharp channeling peaks do not move with the scanning probe. Through a quantitative comparison between experimental image and simulation, a Fourier-space approach is proposed to estimate defocus and sample thickness. The effective atom size in Z-contrast imaging depends on the annular detector's inner angle. Therefore, an optimum angle exists for the highest resolution as a trade-off between reduced atom size and reduced signal with limited information transfer due to noise.
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6031, USA.
authors.forename: Yiping
authors.initials: Y
authors.lastname: Peng
authors.forename: Mark P
authors.initials: MP
authors.lastname: Oxley
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Lupini
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Chisholm
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Pennycook
mesh_terms: D007089:Image Enhancement; D008433:Mathematics; D017348:Microscopy, Electron, Scanning Transmission / Q000379:methods*