LONDON, Sept 13: Electrons that break the rules and move perpendicular to the applied electric field could be the key to delivering next generation, low-energy computers, scientists say.
Researchers from the University of Manchester and Massachusetts Institute of Technology have described a material in which electrons move at a controllable angle to applied fields, similar to sailboats driven diagonally to the wind.
The material is graphene – one atom-thick chicken wire made from carbon – but with a difference.
It is transformed to a new so-called superlattice state by placing it on top of boron nitride, also known as ‘white graphite’, and then aligning the crystal lattices of the two materials.
In contrast to metallic graphene, a graphene superlattice behaves as a semiconductor.
In original graphene, charge carriers behave like massless neutrinos moving at the speed of light and having the electron charge.
Although an excellent conductor, graphene does not allow for easy switching on and off of current, which is at the heart of what a transistor does.
Electrons in graphene superlattices are different and behave as neutrinos that acquired a notable mass.
This results in a new, relativistic behaviour so that electrons can now skew at large angles to applied fields. The effect is huge, as found in the Manchester-MIT experiments.
Beyond the discovery, the observed phenomenon may also help enhance the performance of graphene electronics, making it a worthy companion to silicon, researchers said.
The work suggests that transistors made from graphene superlattices should consume less energy than conventional semiconductor transistors because charge carriers drift perpendicular to the electric field, which results in little energy dissipation.
The research is published in the journal Science. (PTI)
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