Honglong Zhao

Graphene is a carbon film exactly one atom thick. Two such sheets placed on top of each other with a slight twist behave very differently from a single sheet. At an angle of about 1.1 degrees, electrons slow down so much that the material can become a superconductor or an insulator — depending on the conditions.

The electron beam of a microscope usually flies through emptiness, like a courier on an empty highway. Any air molecule is a bump that makes it bounce and lose direction. So before, to examine a sample, you had to freeze it, dry it, or coat it with metal—and still you could only look in a vacuum.