Documenting the Coming Singularity

Tuesday, April 10, 2007

Graphene - Thin is In

Billed as "the thinnest of all possible materials in the universe," graphene is a one-atom-thick sheet of carbon that looks like "molecular chicken wire." The latest in a series of carbon discoveries (after buckyballs and nanotubes), is easier and cheaper to make than its older brothers. The method for splitting carbon into thin sheets involves, of all things, sticky tape. It turns out that ordinary sticky tape is ideal for pulling apart layers of graphite until a single-atom layer is left.

Graphene has some very interesting properties:

Because of how the electrons flowing in graphene interact with the honeycomb chicken-wire structure, they behave as if they have no mass, always traveling at the same speed regardless of their energy, like particles of light. Dr. Beenakker at Leiden has proposed taking advantage of graphene’s unusual behavior in a new type of electronics that he calls “valleytronics.”

Independently, Dr. Geim and Dr. Kim at Columbia demonstrated a phenomenon known as the quantum Hall effect, where the electrical resistance perpendicular to the current and an applied magnetic field jumps between certain discrete values. The quantum Hall effect is usually seen just at very low temperatures in semiconductors, but it occurs in graphene at room temperature. A more recent paper by Dr. Geim and his collaborators describes a suspended graphene sheet as not flat, but wavy.

In a sense, nanotubes are nothing more than unrolled graphene. Will it be possible to overcome the difficulties of producing nanotubes of specific types and lengths by working instead with the flat graphene, which is simple to make and manipulate. I'll be watching the progress of this research closely, because as soon as nanotubes are ready for prime time, the applications will be astounding.

(Via The New York Times)


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