Using a one-of-a-kind instrument designed and built at the National Institute of Standards and Technology (NIST), an international team of researchers have unveiled a quartet of graphene’s electron states and discovered that electrons in graphene can split up into an unexpected and tantalizing set of energy levels when exposed to extremely low temperatures and extremely high magnetic fields. Published in the Sept. 9th, 2010, issue of Nature,* this new research raises several intriguing questions about the fundamental physics of this exciting material and reveals new effects that may make graphene even more powerful than previously expected for practical applications.
Graphene is one of the simplest materials—a single-atom-thick sheet of carbon atoms arranged in a honeycomb-like lattice—yet it has many remarkable and surprisingly complex properties. Measuring and understanding how electrons carry current through the sheet is important to realizing its technological promise in wide-ranging applications, including high-speed electronics and sensors.
One possible explanation for this behavior, the team says, is that the electrons have formed a “condensate” in which they cease moving independently of one another and act as a single coordinated unit. If so, the work could point the way to the creation of smaller, very-low-heat-producing, highly energy efficient electronic devices based upon graphene.
The research team includes collaborators from NIST, the University of Maryland, Seoul National University, the Georgia Institute of Technology and the University of Texas at Austin. For more details, see NIST's Sept. 8th, 2010, news announcement, “NIST Researchers Hear Puzzling New Physics from Graphene Quartet’s Quantum Harmonies” online at www.nist.gov/cnst/graphene_quartet.
* Y.J. Song, A.F. Otte, Y. Kuk, Y.Hu, D.B. Torrance, P.N. First, W.A. de Heer, H. Min, S. Adam, M.D. Stiles, A.H. MacDonald and J.A. Stroscio. High resolution tunneling spectroscopy of a graphene quartet. Nature. Sept. 9, 2010.
**D.L. Miller, K.D. Kubista, G.M. Rutter, Ming Ruan, W.A. de Heer, M. Kindermann, P.N. First and J.A. Stroscio. Real-space mapping of magnetically quantized graphene states. Nature Physics. Published online Aug. 8, 2010. www.nature.com/nphys/journal/vaop/ncurrent/.
Contact: Mark Esser email@example.com 301-975-8735 National Institute of Standards and Technology (NIST)