The 3d Parameters Of A (Nano)Crystal From Lattice Images At Two Tilts

Abstract

Various techniques have been developed to infer the 3D relationship of reciprocal lattice vectors from electron diffraction patterns taken at different specimen orientations. Such relationship is subsequently applied in crystallographic analyses. Due to the transmitted nature of the electron beam, TEM images present 3D information averaged throughout the thickness of the specimen on each micrograph. Techniques for acquiring 3D information from such images include stereomicroscopy for characterizing irregular dislocation networks, and 3D reconstruction of nonperiodic macromolecular assemblies. Prospects for finding the 3D lattice parameters of nanocrystals from HREM images taken at different specimen orientations have been discussed. Here we apply this stereo lattice imaging to a 7 nm crystal, and discuss its application to compact fee and bec lattices in general. Results on other lattice types will be published separately.Generally 3 non-coplanar lattice vectors seen along 2 different zone axes are sufficient for inferring a subset of the 3D reciprocal lattice of a single crystal.