Ultrafast imaging of electron waves in graphene (w/ Video)

November 10, 2010, Argonne National Laboratory
A frame from one of the electron-motion movies (watch the entire sequences below).

The fastest "movies" ever made of electron motion have been captured by researchers using the U.S. Department of Energy’s Advanced Photon Source (APS) at Argonne and the Frederick Seitz Materials Research Laboratory at the University of Illinois at Urbana-Champaign (UIUC). The movies, which were created by scattering x-rays off of graphene, show that the interaction among graphene’s electrons is surprisingly weak.

Using inelastic x-ray scattering experiments at the X-ray Science Division 9-ID x-ray beamline at the APS, physicists from UIUC imaged the motion of electrons in with resolutions of 0.533 Å and 10.3 attoseconds. Their results were published in the November 5 issue of Science.

Exactly how small and how fast are these measurements? An angstrom is 1/10,000,000,000 of a meter, about the width of a hydrogen atom. And an attosecond is to a second as a second is to the age of the Universe.

Animation of n(x,y,t) at two different vertical scales.

The 2010 Nobel Prize for Physics was awarded to Andre Geim and Konstantin Novoselov for their work on graphene, a single-atom-thick sheet of carbon atoms arrayed in a honeycomb pattern that exhibits many intriguing properties, including great strength, flexibility, excellent electrical conductivity, and heat resistance. As a result, graphene is a candidate material for a wide range of applications, including a new generation of low-cost, flexible electronics. A major outstanding question about this material is whether the electrons in graphene move independently, or if their motion is correlated by Coulomb repulsion.

The researchers in this study found that graphene screens Coulomb interactions surprisingly effectively, causing it to act like a simple, independent-electron semimetal. Their work explains several mysteries, including why freestanding graphene fails to become an insulator as predicted. The study also demonstrates a new approach to studying ultrafast dynamics, creating a new window on the most fundamental properties of materials.

Explore further: Graphene pioneers follow in Nobel footsteps

More information: James P. Reed, et al. “The Effective Fine-Structure Constant of Freestanding Graphene Measured in Graphite,” Science 330(6005), 805 (5 November 2010). DOI:10.1126/science.1190920

Related Stories

Professor scoops top prize for 2D atomic crystals discovery

October 19, 2006

Professor Andre Geim of the School of Physics and Astronomy has been awarded the 2007 Mott Medal and Prize by the Institute of Physics for his ground-breaking work. The research of Professor Geim, Dr Kostya Novoselov and ...

Light-speed nanotech: Controlling the nature of graphene

January 21, 2009

Researchers at Rensselaer Polytechnic Institute have discovered a new method for controlling the nature of graphene, bringing academia and industry potentially one step closer to realizing the mass production of graphene-based ...

Recommended for you

Meteorite source in asteroid belt not a single debris field

February 17, 2019

A new study published online in Meteoritics and Planetary Science finds that our most common meteorites, those known as L chondrites, come from at least two different debris fields in the asteroid belt. The belt contains ...

Diagnosing 'art acne' in Georgia O'Keeffe's paintings

February 17, 2019

Even Georgia O'Keeffe noticed the pin-sized blisters bubbling on the surface of her paintings. For decades, conservationists and scholars assumed these tiny protrusions were grains of sand, kicked up from the New Mexico desert ...

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...

What rising seas mean for local economies

February 15, 2019

Impacts from climate change are not always easy to see. But for many local businesses in coastal communities across the United States, the evidence is right outside their doors—or in their parking lots.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.