“What could we do with layered structures with just the right layers?” asked Richard Feynman in his famous 1959 lecture, “There’s plenty of room at the bottom.” With the help of the amazing developments of the past several years, we are coming close to answering that question. Whereas thin layers and multilayers of various kinds have long been known to technology, researchers are now learning to create uniform, atomically thin layers and manipulate them into novel solids with a broad range of physical properties.
Layered materials are characterized by extended crystalline planar structures held together by strong in-plane covalent bonds and weak out-of-plane van der Waals forces. Individual layers can easily be removed by breaking the van der Waals bonds, with little damage either to the remaining structure or to the extracted layer. For example, layers of graphene can be peeled away from bulk graphite with adhesive tape. Hence layered...
