Superconductivity is a phenomenon where certain materials can conduct electricity with zero resistance. Obviously, this has enormous technological advantages, which makes superconductivity one of the most intensely researched fields in the world.

But superconductivity is not straightforward. Take, for example, the double-dome effect. When scientists plot where superconductivity appears in material as they change how many electrons are in it, the material’s superconducting regions sometimes look like two separate “domes” on a graph.

In other words, the material becomes superconducting, then stops, then becomes superconducting again as we keep changing its electron density.