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In transmission electron micrography of few-layer thick graphene samples, two distinct regions, a region of superlattice and an adjacent region of parallel straight bands, are seen. These two features are explained as Moire patterns produced by (1) rotation of top part of one of the graphene layers and (2) a small change in the shape of the bottom part of the same layer. It is interesting to note that for the first time, Moire pattern of parallel straight bands is observed and satisfactorily explained. V

Evolution of structure, morphology, and reactivity of hydrogenated amorphous silicon film surfaces grown by molecular-dynamics simulation

Here, we apply revolving scanning transmission electron microscopy to measure lattice strain across a sample using a single reference area. To do so, we remove image distortion introduced by sample drift, which usually restricts strain analysis to a single image. Overcoming this challenge, we show that it is possible to use strain reference areas elsewhere in the sample, thereby enabling reliable strain mapping across large areas. As a prototypical example, we determine the strain present within the microstructure of a Ni-based superalloy directly from atom column positions as well as geometric phase analysis. While maintaining atomic resolution, we quantify strain within nanoscale regions and demonstrate that large, unit-cell level strain fluctuations are present within the intermetallic phase.

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