U. Manchester's Andre Geim: Sticking with
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Grahene is one atom thick, which makes it the thinnest
material in the universe, or at least tied for the
thinnest should some novel competitor be lurking out
there somewhere, as yet undiscovered. It’s a
crystal arranged in a chicken-wire or honeycomb
lattice, and a very high-quality crystal at that.
According to its creator, the University of Manchester
solid-state physicist Andre Geim, no one has yet found
a single vacancy or dislocation in a graphene crystal
made by following his recipe. Graphene is also highly
conductive, conducting both heat and electricity better
than any other material, and it is strong. Stronger
than diamond, if you could imagine a diamond as thin as
Ever since Geim published his first paper on graphene in Science
in October, 2004—"Electric field effect in atomically thin carbon
films"—the two-dimensional variation on graphite has taken materials
science and condensed-matter physics by storm, while launching Geim into
prominence among Thomson Reuters’ measures of hot researchers in the
field. Geim’s 2004 Science paper has now been cited nearly
600 times (see adjoining table), eclipsed only by a November, 2005 article
in Nature on the unique quantum mechanical properties of these
materials, "Two-dimensional gas of massless Dirac fermions in graphene,"
which has been cited roughly 650 times. Beginning in early 2007, this paper
spent more than a year on the upper rungs of the Science
Watch® Physics Top Ten.
More recently, the latest bimonthly file of the Hot Papers Database shows
that seven reports from Geim and colleagues published in the last two years
are currently being cited at a notably high rate compared to papers of
similar type and age.
materials like this before, in fact, it was
assumed that they couldn’t exist."
Geim's research has wielded impact beyond the physics world. In 2007, for
example, one of his previous reports, discussing his work on "gecko
tape"—a microfabricated adhesive that mimics the super-sticky action
of the gecko lizard's footpads—was identified as a core paper in a
Research Front in the field of Microbiology.
Geim is also known for injecting, quite literally, a bit of levity into
science, with the 1997 experimental levitation of a frog by means of a
magnetic field. The work earned Geim a share of one of the tongue-in-cheek
IgNobel Awards in 2000, while also entertainingly demonstrating valid
principles of diamagnetism.
Geim, 49, received his Master's in Science degree in 1982 from the Moscow
Physical-Technical University and his Ph.D, five years later, from the
Institute of Solid State physics in Chernogolovka, Russia. After spending
two years as a research scientist at the nearby Institute for
Microelectronics Technology, Geim left for the West to become a visiting
fellow at Nottingham University in the U.K. He led a peripatetic career
through 1994, when he became an associate professor at the University of
Nijmegen in the Netherlands. In 2001, he became a professor of physics at
England’s University of Manchester, where he is also director of the
Centre for Mesoscience & Nanotechnology. In 2007 he was elected a
Fellow of the Royal Society.
Geim spoke to Science Watch from his
Graphene seems to be just one particularly
extraordinary example of a long line of unique discoveries in your
research. How would you characterize your research style?
It is rather unusual, I have to say. I do not dig deep—I graze
shallow. So ever since I was a postdoc, I would go into a different subject
every five years or so. Every time I took a different university position,
I would change subjects. I don't want to carry on studying the same thing
from cradle to grave. Sometimes I joke that I am not interested in doing
re-search, only search. There have been a few hits, like graphene and
levitating frogs and gecko tape. When I moved from Holland to the
University of Manchester, it was a good time to try new subjects, and one
of the things that came out of it was gecko tape and another was graphene,
and a third involved domain walls in magnetic structures. Graphene
certainly turned out to be the biggest hit, scientifically the most
important. Even though gecko tape is very popular these days, we had to
completely abandon it. Graphene turned out to be much, much more important
than anything else.
Is there a common theme to your research
The common theme is to use experimental facilities that are available and
to see what we can do—what other people haven’t done
previously. I’m looking for an unexplored area of research, based on
a combination of knowledge and facilities. I’m not trying to reach
some theoretical goal set forth by someone else. It’s like this kids'
toy, Lego. You have all these different pieces, cubes and stuff, and you
have to build something based strictly on what pieces you’ve got. So
in research, some of the Lego pieces are facilities, some are random
knowledge, and we try to build up something new from that. I guess we could
call it the "Lego Doctrine."
So how did this Lego Doctrine lead you to
We had facilities to study small samples. I have knowledge from
low-dimensional systems that I had worked on during my postdoctoral
studies. The third element here was what I jokingly call scientific spite:
I looked at the carbon-nanotube community and was spiteful about how many
nice results they had. I thought that I could do something like carbon
nanotubes but from a different perspective. Why couldn’t we do carbon
nanotubes, but unfolded? That was the initial idea: try to do something
similar to carbon nanotubes, but do it by starting with graphite and then
polishing the graphite down to a few layers thick, or at least whatever we
could reach. At that time, neither I nor anyone else thought it was
possible to reach a single layer, but 10 or 100 layers seemed quite
reasonable. So that was the goal: make 100-layer graphite and try to study
it, hoping to address problems similar to those in the carbon-nanotube
world. And we started this about five years ago, 2002 to 2003.
So you literally polish the graphite down until
it’s one layer thick?
Highly Cited Papers by
Andre K. Geim and Colleagues,
Published Since 2004
(Ranked by total citations)
K.S. Novoselov, et al.,
"Two-dimensional gas of massless Direc
fermions in graphene," Nature,
438(7065): 197-200, 2005.
K.S. Novoselov, et al., "Electric
field effect in atomically thin carbon
films," Science, 306(5296): 666-9,
A.K. Geim, K.S. Novoselov, "The rise of
graphene," Nature Materials, 6(3):
K.S. Novoselov, et al.,
"Two-dimensional atomic crystals,"
PNAS, 102(30): 10451-3, 2005.
K.S. Novoselov, et al.,
"Unconventional quantum Hall effect and
Berry's phase of 2p bilayer graphene,"
Nature Physics, 2(3): 177-80,
Web of Science®
Let me tell you a nice story: I had a new Chinese Ph.D. student. I bought a
big piece of highly oriented pyralytic graphite, known as HOPG, and I asked
him to make films as thin as possible. Initially I gave him a very fancy
polishing machine. A piece of Lego was in place, see. Three weeks later, he
comes back and says he’s succeeded. He shows me a Petri dish with a
tiny speck of graphite at the bottom. I look in the microscope and see that
it's about 10 microns thick—maybe 1,000 layers. I ask him, "Can you
polish it a little bit more?" And he says he would need another piece of
HOPG, which costs about $300. I must say that I was not very polite when
explaining to him that you don't have to polish off a whole brick to get a
grain of it. His equally polite reply was, "If you’re so clever, try
to do it yourself."
This was a point of no return. I decided to use Scotch tape.
Graphite is a very layered material. It’s like mica. It splits
into planes very easily. So you put Scotch tape on graphite or mica and
peel the top layer. There are flakes of graphite that come off on your
tape. Then you fold the tape in half and stick it to the flakes on top
and split them again. And you repeat this procedure 10 or 20 times. Each
time, the flakes split into thinner and thinner flakes. At the end
you’re left with very thin flakes attached to your tape. You
dissolve the tape and everything goes into solution. It turned
out—and no one would have guessed—that the thin flakes did
not lump and scroll. Within a week we had a working device. It
wasn’t graphene. It was still graphite—maybe 10 layers
thick—but we had gone farther than anyone else in this direction,
and we started to make transistors from it.
Yes. It’s now called the "Scotch tape technique." I fought against
this name, but lost. It doesn't sound very high-tech, does it? Then again,
you could equally call the way nanotubes are grown a "barbeque technique."
Nanotubes and all sorts of fullerenes can be found in soot at the bottom of
a barbeque tray. There are now more sophisticated ways of getting graphene,
but Scotch tape gave us the first glimpse of what’s
possible—that you can essentially pull a single atomic plane off of
What’s the difference between graphite and
Graphene is a single atomic plane of graphite. Graphite is a stack of
graphene planes. It’s very important to emphasize that all matter,
all materials we knew before this, were and are three-dimensional
materials. Even those that were called one- or two-dimensional were never
actually one or two. Take carbon nanotubes. People might refer to them as
one-dimensional, but if you look carefully, you see that a nanotube is a
cylinder—thin and long but still a three-dimensional object. Here,
for the first time ever, we really are dealing with strictly
two-dimensional matter. We’ve never known materials like this before.
In fact, it was assumed that they couldn’t exist.
What were the arguments against 2-D
There are very powerful theoretical
arguments that 2-D materials cannot be grown, because whenever you try to
grow something of dimensionality less than three in our three-dimensional
world, it will morph and go through all sorts of three-dimensional
structures. We fooled nature by making first a three-dimensional material,
which is graphite, and then pulling an individual layer out of it. This way
is not forbidden by theory.
You’ve said these graphene sheets are
revealing secrets of fundamental physics. Can you tell us more about
If graphene were just the thinnest material and
so on, I would not be giving this interview. It's an extraordinary
system and provides a cornucopia of new physics. The most important
physics comes from the very unusual electronic properties of this
material. The point is that in all material we knew about until graphene
came along, charge carriers could be described classically as bullets or
billiard balls moving through the material, or quantum mechanically as
these electron waves described by the wave equation of quantum physics,
the Schrödinger equation. In graphene, conducting electrons arrange
themselves into new types of quasi-particles, or new types of waves, if
you wish, which move according to the laws of relativistic quantum
physics—the Dirac equation. They behave like neutrinos or
electrons moving at close to the speed of light. I like to emphasize
that they are not really relativistic; they just mimic these
relativistic laws. That's a new kind of thing to study. It's like the
Large Hadron Collider, but on your desktop.
What technological applications do you foresee for
graphene, and are we going to need new technologies to create it to make
these applications viable?
Well, there is another way of producing graphene, and it’s called
epitaxial growth. You can essentially grow a single layer on top of other
crystals. If you find a crystal with a matching substrate, you can grow
graphene on top of this substrate, too. It’s been shown that this can
be done on silicon carbide, iridium, nickel, and other materials. Many
applications, especially in electronics, require graphene wafers and are
hard to imagine without epitaxial growth.
As for what those applications are, the idea is to consider graphene as
unfolded carbon nanotubes. Whatever people have suggested for carbon
nanotubes can then be done with graphene. I have to say, though, that
I’m always very skeptical about applications. When someone asks about
applications in my talks, I usually tell a story about how I was on a boat
one day watching dolphins, and they were jumping out of the water, allowing
people to nearly touch them. Everyone was mesmerized by these magnificent
creatures. It was an extraordinary romantic moment—well, until a
little boy shouted out, "Mom, can we eat them?" It's a similar matter
here—as in, okay, we just found this extraordinary material, so we're
enjoying this romantic moment, and now people are asking if we can eat it
or not. Probably we can, but you have to step back and enjoy the moment
So what are the applications? How do you serve up
If you insist on going in this direction, we can talk about the realistic
applications, and then about the dreams that might someday come true. In
realistic applications, people have now learned how to make graphene
suspensions, not too dissimilar to dissolving Scotch tape but on an
industrial scale. You use this suspension as a filler in plastic to make
composite materials—conductive plastics that might not be as strong
as graphene itself but are strong enough. Several groups also used graphene
suspension to make a conductive, transparent film. So you have glass. You
spin your suspension over this glass and you make optically transparent and
conductive films. These are used, of course, in many, many applications.
The easiest one is right in front of you, your LCD screen, and graphene
looks very promising for this kind of application.
An example of a graphene dream could be what I call "Graphenium Inside,"
like "Pentium Inside." We’re about to reach the point where silicon
can’t be miniaturized any further; the material itself becomes
unstable at sizes down to 10 nanometers. People are looking for a material
to substitute, to take over from silicon and go to smaller sizes. There
have been about ten candidates in the last ten years and all, in my
opinion, have failed miserably. Graphene is a strong possibility as a
substitute. This material is not great for computer chips with large
transistors, but as you decrease in size, it becomes far stronger. Every
big-name company, from Intel to IBM to Samsung, now has its fingers in this
particular pie, but it’s still a dream at the moment, not a realistic
You said your research style is to graze and find a new field every
five years. You published your discovery of graphene in 2004. Are you
planning on leaving the field next year?
No, although I’m often asked that question by my colleagues who, I
believe, hope I’ll leave the field to them. No chance, guys! You'll
have to cope with my sarcastic jokes for longer. With graphene, each year
brings a new result, a new sub-area of research that opens up and sparks a
gold rush. I want to put many more stakes in the ground before it’s
covered completely, before all the interesting science is claimed and
taken. Then it will be time to move on.
Read two Fast Moving Front
commentary features from Andre Geim. The
is regarding his Science paper published in October, 2004 titled,
"Electric field effect in atomically thin carbon films." The
is in regards to his Nature Materials paper published in July,
2003 titled, "Microfabricated adhesive mimicking gecko foot-hair." This
commentary includes an image of imetic gecko hairs seen in a scanning
Keywords: Andre K. Geim, University of Manchester, graphite,
graphene, materials science, gecko tape, nanotubes.