Picometer accuracy in measuring lattice displacements across planar faults by interferometry in coherent electron diffraction
We calculate the shadow image in far field below a thin crystal when a coherent electron source is placed at micrometer distances above the specimen, and note that the presence of a planar fault results in very strong oscillatory contrast. We realize these predictions experimentally using a field-emission electron source in a microscope. With this technique, we determine displacement vectors at planar faults with an accuracy down to 1 pm in studies of the Bi2Sr2CaCu2O8 superconductor containing thin intercalated layers.
Wu
L
Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973, USA.
Zhu
Y
Tafto
J