Graphite Found to Exhibit Surprising Quantum Effects

Albert Einstein, Paul Dirac and other founding physicists may have used
pencils to work out the details of relativity and quantum mechanics. Now
their modern successors are employing pencil lead in a new way to prove
those theories--and potentially point the way toward a whole new form of
electronics.

Pencil lead is actually graphite--a carbon mineral that, when dragged across
paper, leaves writing behind because its atomic layers separate easily. This
also means that it is an excellent conductor of electricity. Last year,
Andre Geim of the University of Manchester in the U.K. used adhesive tape to
strip graphite down to a layer just one atom thick; they called this
superthin layer of graphite "graphene."

Experiments on graphene have revealed some strange phenomena, as detailed in
two papers in today's Nature. The two-dimensional material remains capable
of conducting electricity thanks to the free-floating electron in the
honeycomb structure of carbon atoms. But these electrons display some
unusual properties.

Geim's team found that they do not slow down, even at very low temperatures.
In essence, the electrons act as if they have no mass, or no "rest mass," to
use the more precise phrase from special relativity. It also means that
graphite--at least the two-dimensional variety--never stops conducting.
Dubbing these pseudo-relativistic particles "massless Dirac fermions," the
researchers also proved that they travel far faster than electrons in other
semiconductors. As such, they conform to that famous equation E=mc2 (with
their actual speed, some 400 times slower than the speed of light, standing
in for c).

Physicists at Columbia University, led by Philip Kim, independently
confirmed these findings and also found that the massless electrons
fulfilled the predictions of the Hall effect. (Edwin Hall proved in 1879
that applying a magnetic field at a right angle to a conducting material
would create a voltage that is perpendicular to the regular flow of current
through that material.) This effect is also applicable at the quantum level,
with one caveat: instead of the voltage smoothly increasing as the magnetic
field intensifies, the voltage jumps up in steps. And that is exactly how
the massless electrons in the graphene behaved, according to both groups.

Ultimately, Kim writes, the findings may "lead to new applications in
carbon-based electronic and magneto-electronic devices," though further
research is needed. It also means that the graphite left behind by a
pencil--stripped down to a layer one atom thick--can be used to prove the
theories scrawled in pencil by physicists of old. --David Biello

Full Text from Scientific American
http://www.sciam.com/article.cfm?cha...5483414B7F0000


--
Posted by
Robert Karl Stonjek

Robert Karl Stonjek wrote:
Graphite Found to Exhibit Surprising Quantum Effects

Albert Einstein, Paul Dirac and other founding physicists may have used
pencils to work out the details of relativity and quantum mechanics. Now
their modern successors are employing pencil lead in a new way to prove
those theories--and potentially point the way toward a whole new form of
electronics.

Pencil lead is actually graphite--a carbon mineral that, when dragged across
paper, leaves writing behind because its atomic layers separate easily. This
also means that it is an excellent conductor of electricity. Last year,
Andre Geim of the University of Manchester in the U.K. used adhesive tape to
strip graphite down to a layer just one atom thick; they called this
superthin layer of graphite "graphene."

Experiments on graphene have revealed some strange phenomena, as detailed in
two papers in today's Nature. The two-dimensional material remains capable
of conducting electricity thanks to the free-floating electron in the
honeycomb structure of carbon atoms. But these electrons display some
unusual properties.

Geim's team found that they do not slow down, even at very low temperatures.
In essence, the electrons act as if they have no mass, or no "rest mass," to
use the more precise phrase from special relativity. It also means that
graphite--at least the two-dimensional variety--never stops conducting.
Dubbing these pseudo-relativistic particles "massless Dirac fermions," the
researchers also proved that they travel far faster than electrons in other
semiconductors. As such, they conform to that famous equation E=mc2 (with
their actual speed, some 400 times slower than the speed of light, standing
in for c).

Physicists at Columbia University, led by Philip Kim, independently
confirmed these findings and also found that the massless electrons
fulfilled the predictions of the Hall effect. (Edwin Hall proved in 1879
that applying a magnetic field at a right angle to a conducting material
would create a voltage that is perpendicular to the regular flow of current
through that material.) This effect is also applicable at the quantum level,
with one caveat: instead of the voltage smoothly increasing as the magnetic
field intensifies, the voltage jumps up in steps. And that is exactly how
the massless electrons in the graphene behaved, according to both groups.

Ultimately, Kim writes, the findings may "lead to new applications in
carbon-based electronic and magneto-electronic devices," though further
research is needed. It also means that the graphite left behind by a
pencil--stripped down to a layer one atom thick--can be used to prove the
theories scrawled in pencil by physicists of old. --David Biello

Full Text from Scientific American
http://www.sciam.com/article.cfm?cha...5483414B7F0000



Also

Electrons lose their mass in carbon sheets (Nov 9)
http://physicsweb.org/article/news/9/11/6

Two teams of physicists have discovered previously unseen exotic
behaviour in sheets of carbon atoms. The teams have shown that electrons
move through the sheets as if they have no rest mass. They have also
observed a minimum value of conductivity for the sheets and an unusual
form of the quantum Hall effect (Nature 438 197 and 201).

what is
'as if they have no mass'???!!

they must make up their minds
do those electrons have mass
or dont they have mass
there is nothing in between

if there is for them something in between means that
*they are confused*!!

2 did QM predicted it or may be the QM people will get up now
and say 'we can explain it' as it usually their habit?

3 just remember the new simple and powerful postulate;

No mass - no real physics!!

ATB
Y.Porat
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