graphene
/ GRAF-een /
Think of the soft grey graphite in a pencil. It is built from millions of paper-thin sheets stacked loosely on top of each other, which is why a pencil leaves a mark: the sheets slide off and stay on the page. Peel away every layer until a single sheet is left, just one atom thick, and you have graphene.
Graphene is one flat layer of carbon atoms locked into a honeycomb pattern, the same six-sided tiling as a beehive. Each carbon holds tight to three neighbors, which makes the sheet extraordinarily strong for its weight, and leaves one electron per atom free to glide across the whole surface. Because of this honeycomb arrangement, those roaming electrons behave in an unusual way — they move as if they had no mass at all, and they travel with remarkably few collisions, giving graphene far higher electron mobility than ordinary metals.
Graphene matters because it was the first truly two-dimensional material ever isolated, and it showed that a crystal one atom thick can be stable and remarkably useful — strong, flexible, transparent, and an excellent conductor. The honest caveat is that being all-surface and ultra-thin makes it hard to make in large, flawless pieces and tricky to switch fully off, so despite the early hype it has been slow to replace silicon in everyday electronics.
The two scientists who first isolated graphene in 2004 did it with ordinary sticky tape: they pressed it onto a flake of graphite, peeled, and folded the tape over and over, halving the thickness each time, until a single atomic layer was left clinging to the adhesive.
Graphene was first peeled from graphite with nothing fancier than adhesive tape.
People sometimes call graphene a metal because it conducts so well, but it is more precisely a 'semimetal': at perfect purity its conduction and valence bands just touch at single points, so it has no electrons to spare exactly there — a delicate balance that ordinary metals never have.