![]() ![]() “What got us interested in this topic,” Ross says, was “what happens when a 2D material and a 3D material are put together. While these 2D pairings have attracted scientific attention worldwide, she says, little has been known about what happens where 2D materials meet regular 3D solids. In the case of 2D materials, “it seems like anything, every interesting materials property you can think of, you can somehow modulate or change by twisting the 2D materials with respect to each other,” says Ross, who is the Ellen Swallow Richards Professor at MIT. That causes the chicken-wire-like atomic lattices to form moiré patterns, the kinds of odd bands and blobs that sometimes appear when taking a picture of a printed image, or through a window screen. Pairs of two-dimensional materials such as graphene or hexagonal boron nitride can exhibit amazing variations in their behavior when the two sheets are just slightly twisted relative to each other. The new findings are described today in the journal Nature Communications, in a paper by MIT graduate students Kate Reidy and Georgios Varnavides, professors of materials science and engineering Frances Ross, Jim LeBeau, and Polina Anikeeva, and five others at MIT, Harvard University, and the University of Victoria in Canada. An international team led by MIT researchers has now come up with a way of imaging what goes on at these interfaces, down to the level of individual atoms, and of correlating the moiré patterns at the 2D-3D boundary with the resulting changes in the material’s properties. It also changes the way electrons move through the material, in potentially useful ways.īut for practical applications, such two-dimensional materials must at some point connect with the ordinary world of 3D materials. ![]() This creates what are known as moiré patterns, where tiny shifts in the alignment of atoms between the two sheets create larger-scale patterns. In recent years, engineers have found ways to modify the properties of some “two- dimensional” materials, which are just one or a few atoms thick, by stacking two layers together and rotating one slightly in relation to the other. ![]()
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