When two sheets of graphene are stacked, and twisted with respect to one another, they form a metameterial, with properties partially dependent on the twist ang

When two sheets of graphene are stacked, and twisted with respect to one another, they form a metameterial, with properties partially dependent on the twist angle. At a twist angle of 1.1 degrees, the energy required for an electron in one sheet to tunnel to the other sheet drops to zero. The problem is that certain angles represent a lower-energy state than others, so twisting to a magic angle also requires overcoming some buckling and creasing in the individual sheets, that allow regions to locally align to a non-magic angle (like zero degrees). This confounds measurements of the properties of the metamaterial. Certain angles have been shown to exhibit superconductivity. While less useful than previously discovered superconductors for the purpose of moving electrons, these are more useful for studying superconductivity itself, because the superconductor is 2.5d, composed of a single type of atom, each with identical bond configurations. A lot of the variables that appear in other superconductors drop out.