Friday, April 4, 2008

Scientists Create Material One Atom Thick

PhD student Rahul Nair (who carried out this work) shows his research sample: a scaffold in which several apertures are covered by graphene
Rahul Nair's research sample: a scaffold with apertures covered by graphene

The foundations of the universe have been glimpsed in Manchester by scientists who have created the thinnest possible material.

  • Scientists create world's thinnest material
  • Do pencils point to the Holy Grail of physics?
  • Flat, parallel sheets of carbon atoms in the graphite of pencil lead have been peeled apart by the scientists to yield a sheet a single atom thick that has peculiar properties which made the fundamental feat possible.

    This new material, called graphene, is exciting physicists worldwide because it provides the wherewithal to probe the workings of the universe and without the need for exotic equipment, such as the £4.5 billion atom smasher being readied for use near Geneva.

    Today, in the journal Science, Prof Andre Geim of Manchester University and his colleagues at The University of Minho in Portugal, say they have used graphene to measure an important and enigmatic fundamental constant of nature - the fine structure constant.

    Working with Rahul Nair and Peter Blake he made large suspended membranes of graphene so that one can easily see light passing through this thinnest of all materials.

    The 2.3 per cent of light that it absorbed could then be used to calculate the constant, which shows the interaction between very fast moving electrical charges in the material and light, and it is close to 1/137.

    This is one of the exact numbers; so-called fundamental or universal constants such as the speed of light and the electric charge of an electron, that play a crucial role in making the cosmos the place it is. Among them, the fine structure constant is arguably most mysterious, says Prof Geim, who discovered graphene with Dr Kostya Novoselov a few years ago.

    "Change this fine tuned number by only a few percent and the life would not be here because nuclear reactions in which carbon is generated from lighter elements in burning stars would be forbidden," says Prof Geim. "No carbon means no life."

    Researchers say the simplicity of the Manchester experiment is "truly amazing" as measurements of fundamental constants normally require sophisticated facilities and special conditions."We were absolutely flabbergasted when realised that such a fundamental effect could be measured in such a simple way. One can have a glimpse of the very foundations of our universe just looking through graphene," says Prof Geim.

    Graphene behaves as if the electrical current within it is not carried by normal electrons but by charged particles with no mass at all. Scientists call them "Dirac fermions" and love to study them, says Prof Geim.

    The odds are that graphene can be used to make ballistic transistors - ultimately faster than any current technology. "A ballistic transistor is one in which electrons can shoot through without collisions, like a bullet," he says

    "Graphene continues to surprise beyond the wildest imagination of the early days when we found this material," he adds. "It works like a magic wand - whatever property or phenomenon you address with graphene, it brings you the answers as if by magic."

    Prof Geim is also known for his earlier use of magnetic fields to levitate frogs and his reation of the dry adhesive that is inspired by the same principle that enables a gecko to crawl along ceilings.

    Original here

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