Decoherence in electron backscattering by kinked dislocations.
A model is proposed that explains the origin of the bright contrast of dislocation walls consisting of edge dislocation dipoles in electron channelling contrast images (ECCI) of fatigued crystals, when the incident beam is parallel to the edge dislocations. The model is based on the assumption that the contrast arises from the dislocation segments terminating the dipoles. These are modelled as screw-type kinks which scatter electrons. Scattering by randomly distributed kinks leads to the randomization of phase of transmitted and diffracted beams and suppresses the anomalous transmission of electrons. The predicted behaviour of electron-channeling contrast images agrees well with experimental observations.With apologies for using two beams instead of three!
Dudarev
SL
Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, England. sergei.dudarev@materials.oxford.ac.uk
Ahmed
J
Hirsch
PB
Wilkinson
AJ