Jiabin Yu

In a superconductor, electrons pair up like dancers holding hands. Usually, the distance between them, the pair size, depends on how fast they move and how strongly they are bound. But sometimes the dance floor almost disappears, and there's nowhere to move. This happens in materials with flat electronic bands: electrons nearly freeze, and the usual rules stop working.

In an ultrathin sheet of four-layer graphene, electrons can behave like a frozen liquid. When cooled strongly and subjected to an electric field, they stop darting around and line up into a regular pattern — a Wigner crystal. It's similar to how water droplets on a frosty morning turn into ice honeycombs.