Insulator or superconductor? Physicists find graphene is both

It's hard to believe that a single material can be described by as many superlatives as graphene can. Since its discovery in 2004, scientists have found that the lacy, honeycomb-like sheet of carbon atoms - essentially the most microscopic shaving of pencil lead you can imagine - is not just the thinnest material known in the world, but also incredibly light and flexible, hundreds of times stronger than steel, and more electrically conductive than copper. Now physicists at MIT and Harvard University have found the wonder material can exhibit even more curious electronic properties. In two papers , the team reports it can tune graphene to behave at two electrical extremes: as an insulator, in which electrons are completely blocked from flowing; and as a superconductor, in which electrical current can stream through without resistance. Researchers in the past, including this team, have been able to synthesize graphene superconductors by placing the material in contact with other superconducting metals - an arrangement that allows graphene to inherit some superconducting behaviors. This time around, the team found a way to make graphene superconduct on its own, demonstrating that superconductivity can be an intrinsic quality in the purely carbon-based material. The physicists accomplished this by creating a "superlattice" of two graphene sheets stacked together - not precisely on top of each other, but rotated ever so slightly, at a "magic angle" of 1.1 degrees.