For one, creating
sheets of graphene, even as it has gotten much easier in the recent
past, is still somewhat difficult. One cannot simply use a press to
create a sheet of carbon. Fortunately, advances by groups using
common ingredients like sheets
of indium or camera
flashes look promising not only for raw material for studies, but
for pre-printed electronic circuits.
Though the strength of
graphene is undoubtedly an area of interest, its peculiar electrical
properties may be of more use to all industries. Unlike most other
conductors, graphene retains its superior abilities all the way down
to the molecular level. One day time will run out for silicon-based
electronics and it may be this property of graphene that allows it to
take up the reigns for further miniaturization of modern
Another property that sets it apart from metallic
conductors is the way electrons flow through and the effective mass
they carry. In metallic conductors, electrons have to find their way
through a maze of electrical fields produced by the metal atoms. This
causes them to be perceived as if they have more mass than a typical
electron should. The effect is quite the opposite in graphene however
-- the electrons act as if they have little to no mass while they
move through the crystal lattice.
This lack of mass conforms
to the same relativistic equations that are thought to govern the
behavior of particles in a black hole and particle accelerators.
Scientists call this quantum electrodynamics, and until recently, it
has been very difficult to study this effect in graphene, even
knowing that the electrons behave similarly.
cooperation with researchers at Columbia University, have come up
with a method for suspending
a sheet of graphene (PDF) from gold posts using standard
lithography techniques. The idea for this process came from the
team’s realization that part of the reason they weren’t getting
the results they were looking for was due to the sheet of graphene
being used being in contact with whatever material it was being laid
upon for study.
One property they had hoped to see was an
enhanced fractional quantum Hall effect. In a fractional quantum Hall
effect, the interaction of electrons on a two-dimensional plane,
magnetic fields and low temperature create electrons that have
fractional negative charges.
Previous efforts to study the
effect required a sandwich of different semiconductors being cooled
to within a degree of absolute zero, and this only approximated the
effect of a two-dimensional sheet because the movement of the
electrons was confined between the two semiconductors. Using their
new technique, the Columbia group was able to use a true
two-dimensional plane. The suspended sample was cooled to only six
degrees Kelvin and when a magnetic field was applied, this fractional
quantum Hall effect sprang to life just as they had predicted.
this new technique for suspending sheets of graphene, many more such
experiments should be possible for researchers. Unlocking the
mysteries of both graphene itself and exotic quantum electricity and
other effects will undoubtedly bring new ideas and creations to
The Columbia group’s research has been
published in the journal Nature.
quote: ...leaving the sheet of grapehen suspended freely...