Wonder material graphene gets more wonderfully mysterious the closer scientists look. And the latest attempt to understand how the atom-thick sheet of carbon atoms carries current the way it does has left physicists with more questions than they started with.
Researchers at NIST (National Institute of Standards and Technology) subjected sheets of graphene to high vacuum, ultra-low temperatures and vastly large magnetic fields. Sounds intolerable, but in fact graphene remains pristine for weeks under these extreme conditions. Perfect, then for a bit of scientific investigating with a high power scanning probe microscope.
And what they found was that once you start observing at the atomic level in a large magnetic field, the electrons in graphene start behaving in "unexpectedly complex" ways.
From the announcement: Because of the geometry and electromagnetic properties of graphene's structure, an electron in any given energy level populates four possible sublevels, called a "quartet." Theorists have predicted that this quartet of levels would split into different energies when immersed in a magnetic field, but until recently there had not been an instrument sensitive enough to resolve these differences.
And what they saw might have been electrons behaving as a condensate. That is to say, they behave as one unit, rather than as independent entities. Although it is one possible explanation, it has the scientists quite excited:
"If our hypothesis proves to be correct, it could point the way to the creation of smaller, very-low-heat producing, highly energy efficient electronic devices based upon graphene," said Shaffique Adam, a postdoctoral researcher who worked on the project.
The research is published in Nature, but there is lots more from the press announcement here.