We have retold 3 papers by this author. 2 of them with a full read. most often about: graphene, structural_superlubricity, twistronics. 20 co-authors across our retellings.
Two pieces of graphite rub against each other, and the resistance vanishes as if an invisible film of oil separated them. Previously, this was only seen under a microscope, on tiny contact patches.
A door lock with two different keys: one turns easily, the other demands noticeable effort. That is how two layers of hexagonal boron nitride behave when twisted relative to each other. This material consists of boron and nitrogen atoms arranged in a hexagonal lattice, and its layers can sit in different registries, like two identical grids shifted by different angles.
It is easier to turn a jar lid by gripping its edge than its center. Layered crystals such as graphite behave similarly when one layer is twisted relative to another: the resistance arises not from the whole contact area but only from its rim.