Sunday, July 31, 2011

New graphene discovery brings practical devices closer | KurzweilAI

Graphene Electrons

Graphene's band dispersion and low energy Dirac cone in a monolayer of carbon atoms arranged in a hexagonal lattice (credit: University of Manchester)

Interactions between electrons significantly enhance the already high velocity of electrons in graphene, researchers at The University of Manchester have found.

They anticipate their findings will accelerate building graphene-based devices such as touchscreens, ultrafast transistors, and photodetectors.

The researchers used extremely high-quality graphene devices, prepared by suspending sheets of graphene in a vacuum. This eliminated most of the unwanted scattering mechanisms for electrons in graphene, enhancing the effect of electron-on-electron interaction.

This is the first effect of its kind where the interactions between electrons in graphene could be clearly seen.

The electrons in graphene behave like massless Dirac particles that appear in the electronic band structure as gapless excitations with a linear dispersion.

“The exciting physics which we have found in this particular experiment may have an immediate implementation in practical electronic devices,” said University of Manchester professor Kostya Novoselov.

Novoselov, together with Professor Francisco Guinea from Madrid, won the Nobel Prize for Physics in 2010 for “groundbreaking experiments regarding the two-dimensional material graphene.” They used Scotch tape to peel away layers of carbon from a piece of graphite, and were left with a single-atom-thick, two-dimensional film of carbon — graphene.

Ref.: D. C. Elias, et al., Dirac cones reshaped by interaction effects in suspended graphene, Nature Physics, 2011; [DOI:10.1038/nphys2049]