Graphene gazing gives glimpse of foundations of universe

Apr 03, 2008
Fine Structure Constant Measured from Opacity of Graphene Membranes
Magnified image of research samples with small holes covered by graphene. One can see light passing through them by the naked eye. Credit: University of Manchester

Researchers at The University of Manchester have used graphene to measure an important and mysterious fundamental constant - and glimpse the foundations of the universe.

The researchers from The School of Physics and Astronomy, led by Professor Andre Geim, have found that the world’s thinnest material absorbs a well-defined fraction of visible light, which allows the direct determination of the fine structure constant.

Working with Portuguese theorists from The University of Minho in Portugal, Geim and colleagues report their findings online in the latest edition of Science Express. The paper will be published in the journal Science in the coming weeks.

The universe and life on this planet are intimately controlled by several exact numbers; so-called fundamental or universal constants such as the speed of light and the electric charge of an electron.

Among them, the fine structure constant is arguably most mysterious. It defines the interaction between very fast moving electrical charges and light – or electromagnetic waves – and its exact value is close to 1/137.

Prof Geim, who in 2004 discovered graphene with Dr Kostya Novoselov, a one-atom-thick gauze of carbon atoms resembling chicken wire, says: “Change this fine tuned number by only a few percent and the life would not be here because nuclear reactions in which carbon is generated from lighter elements in burning stars would be forbidden. No carbon means no life.”

Geim now working together with PhD students Rahul Nair and Peter Blake have for the first time produced large suspended membranes of graphene so that one can easily see light passing through this thinnest of all materials.

The researchers have found the carbon monolayer is not crystal-clear but notably opaque, absorbing a rather large 2.3 percent of visible light. The experiments supported by theory show this number divided by Pi gives you the exact value of the fine structures constant.

The fundamental reason for this is that electrons in graphene behave as if they have completely lost their mass, as shown in the previous work of the Manchester group and repeated by many researchers worldwide.

The accuracy of the optical determination of the constant so far is relatively low, by metrological standards.

But researchers say the simplicity of the Manchester experiment is “truly amazing” as measurements of fundamental constants normally require sophisticated facilities and special conditions.

With large membranes in hand, Prof Geim says it requires barely anything more sophisticated then a camera to measure visual transparency of graphene.

“We were absolutely flabbergasted when realized that such a fundamental effect could be measured in such a simple way. One can have a glimpse of the very foundations of our universe just looking through graphene,” said Prof Geim.

“Graphene continues to surprise beyond the wildest imagination of the early days when we found this material.

“It works like a magic wand – whatever property or phenomenon you address with graphene, it brings you back a sheer magic.

“I was rather pessimistic about graphene-based technologies coming out of research labs any time soon. I have to admit I was wrong. They are coming sooner rather than later.”

Source: University of Manchester

Explore further: Vortex of electrons provides unprecedented information on magnetic quantum states in solids

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User comments : 8

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NeilFarbstein
1.3 / 5 (4) Apr 03, 2008
I would not be surprised if graphene supports superconductive effects since electrons in that material are "massless"
MikeMarianiMD,FAAP
1.8 / 5 (6) Apr 03, 2008
When Prof Geim exclaims, %u201CChange this fine tuned number by only a few percent and the life would not be here because nuclear reactions in which carbon is generated from lighter elements in burning stars would be forbidden. No carbon means no life%u201D, surely he does not hope to explain to us that life as we know it requires carbon. Anyone even remotely interested in reading the content of this web site is aware that carbon is fundamental to life on Earth.

Is this professor an expert in extraterrestrial life forms as well as physics?
None the entities of which I am aware living in extra-cosmic realities is carbon based.
Silicon?
Honestly, I don%u2019t know. They really don%u2019t like to communicate with the arrogant members of H. sapiens.
I think I know why.

THolley28
1.3 / 5 (3) Apr 03, 2008
I wonder if this is the reason why conductivity is so stupidly high in graphene. What if the weight of the electron does effect its movement therefore affecting electricity? And if that is the case, what if the differences the electrons exibit at less weight can tell us more about particle physics or quantum physics using the mathematical differences in electrical reaction? Some days I wish I actually had a degree to be able to play with the math on this.
out7x
1 / 5 (6) Apr 04, 2008
This article is truly nonsense.
taisha99
3.3 / 5 (3) Apr 04, 2008
Hi
Right - who says all life must be carbon based. Only our VERY local experience and knowledge indicates that. Also idf the constant were different then perhaps something like silicon might behave exactly like carbon.
Nevertheless. Interesting work.
Ged
E_L_Earnhardt
not rated yet Apr 04, 2008
Inteligence will unravel inteligent design - bit by bit. Ignorance is blind by choice!
asiwel
not rated yet Apr 04, 2008
Odd about graphene being "not crystal-clear but notably opaque." I just read an article stating the graphene was the next outstanding new choice for LCD construction because it had much greater light transmission properties than current materials?
asiwel
not rated yet Apr 04, 2008
That article from the Max Plank Insitute about graphene translucency (at least at infrared, better than iridium) is entitled "Carbon electrodes could slash cost of solar panels" 12:43 19 December 2007 from NewScientist.com news service. The "next thing" they were going to try improving was LCD panels.

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