Atom-by-atom imaging of moiré transformations in 2D transition metal dichalcogenides

초록

Understanding the atomic-scale mechanisms that govern the structure of interfaces is critical across materials systems but particularly so for two-dimensional (2D) moire materials. Here, we image, atom-by-atom, the thermally induced structural evolution of twisted bilayer transition metal dichalcogenides using in situ transmission electron microscopy. We observe low-temperature, local conversion of moire superlattice into nanoscale aligned domains. Unexpectedly, this process occurs by nucleating a new grain within one monolayer, whose crystal orientation is templated by the other. The aligned domains grow through collective rotation of moire supercells and hopping of 5|7 defect pairs at moire boundaries. This provides mechanistic insight into the atomic-scale interactions controlling moire structures and illustrates the potential to pattern interfacial structure and properties of 2D materials at the nanoscale.

키워드