title: Low magnification differential phase contrast imaging of electric fields in crystals with fine electron probes.
abstract: To correlate atomistic structure with longer range electric field distribution within materials, it is necessary to use atomically fine electron probes and specimens in on-axis orientation. However, electric field mapping via low magnification differential phase contrast imaging under these conditions raises challenges: electron scattering tends to reduce the beam deflection due to the electric field strength from what simple models predict, and other effects, most notably crystal mistilt, can lead to asymmetric intensity redistribution in the diffraction pattern which is difficult to distinguish from that produced by long range electric fields. Using electron scattering simulations, we explore the effects of such factors on the reliable interpretation and measurement of electric field distributions. In addition to these limitations of principle, some limitations of practice when seeking to perform such measurements using segmented detector systems are also discussed.
authors.affiliation: School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Taplin
authors.affiliation: Institute of Engineering Innovation, School of Engineering, University of Tokyo, Tokyo 113-8656, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Shibata
authors.affiliation: Monash Centre for Electron Microscopy, Monash University, Clayton, Victoria 3800, Australia; Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Weyland
authors.affiliation: School of Physics and Astronomy, Monash University, Clayton, Victoria 3800, Australia. Electronic address: scott.findlay@monash.edu.
authors.forename: S D
authors.initials: SD
authors.lastname: Findlay
keywords: Differential phase contrast; Electric field mapping; Scanning transmission electron microscopy; Segmented detectors