“A new paper attempts to codify and name one particular type of metamaterial that the authors (Justin C. W. Song & Nathaniel M. Gabor) are proposing be called “electron quantum metamaterials.”
“These types of materials are comprised of two or more layers of two-dimensional nanomaterial that are rotated with respect to each other so that special patterns emerge. This is likened to a moire pattern, where two sets of thin parallel lines are offset from each other by a certain amount and that creates an interference pattern. The interference patterns emerges from the specific relationship between the lines.
“Similarly, if you take two layers of, say, carbon nanosheets and rotate or shift them with respect to each other, at certain angles of rotation you get emergent properties that affect how electrons move through the material. In this way you can “tune” the material to make it a superconductor, or insulator, or anything in between….
“This approach has been applied to light in metamaterials, but they authors argue there is even more potential with electrons because electrons interact with each other much more than photons. Therefore the potential for emergent interference type effects is much greater. The result may be designer materials with not only optimal properties in terms of electronics and other applications, but perhaps new functions entirely…
“….it seems that electron quantum metamaterials are a potentially new class of materials with exciting properties. The authors lay out the relevant physics. I still have no idea whether this is the kind of thing we will be seeing in applications in 10 years or 50 years. Perhaps someone reading this has a better sense.”
https://theness.com/neurologicablog/index.php/electron-quantum-metamaterials/#more-11091
https://www.nature.com/articles/s41565-018-0294-9