Finding topological electronic crystal in graphene
The study authors began with two thin layers (flakes) of graphene, a material made of carbon atoms arranged in a honeycomb pattern. Normally, electrons in graphene move freely, similar to how they do in metals like copper.
Next, they stacked the two graphene layers on top of each other but rotated one slightly. This small twist created an interesting pattern called a moiré pattern, where some carbon atoms from both layers were aligned perfectly, but others were misaligned.
When electrons moved through this twisted structure, their behavior completely changed. “For example, the electrons slow way down, and sometimes they develop a twist in their motion, like the vortex in the water at the drain of a bathtub as it is draining out,” Joshua Folk, one of the study authors and a physics professor at the University of British Columbia (UBC), said.