Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers Track Ripples in Freestanding Graphene for First Time

30.04.2014

Clear images advance understanding of fluctuations in 2-D materials

An international team of scientists, led by physicists at the University of Arkansas, has tracked the dynamic movement of ripples in freestanding graphene at the atomic level.


Russell Cothren

Paul Thibado, University of Arkansas

This discovery advances the fundamental understanding of one of the strongest, lightest and most conductive materials, said Paul Thibado, University of Arkansas professor of physics.
“Physicists have known that the ripples must be there and some experiments did find them,” he said. “But they could only measure the ripples as static in time. The theory requires that they fluctuate, more like looking at an ocean with waves. The thermal energy needs to vibrate. Up until our experiment no one had successfully measured this dynamic property of the ripples.”

The team published its findings on Monday, April 28, in Nature Communications, an online journal published by the journal Nature, in a paper titled “Unusual ultra-low frequency fluctuations in freestanding graphene.”

Freestanding graphene could emerge as a replacement for silicon and other materials in microprocessors and next-generation energy devices, but much remains unknown about its mechanical and thermal properties.

Graphene, discovered in 2004, is a one-atom-thick sheet of graphite. Electrons moving through graphite have mass and encounter resistance, but electrons moving through graphene are massless and therefore encounter much less resistance. This makes graphene an excellent candidate material for future energy needs, as well as for use in quantum computers, to enable enormous calculations with little energy use.

The study was led by Peng Xu, a postdoctoral research associate in the department of physics in the J. William Fulbright College of Arts and Sciences at the University of Arkansas.

Xu and Thibado used scanning tunneling microscopy, which produces images of individual atoms on a surface, to measure ultra-low frequency fluctuations in a one-square-angstrom region of freestanding graphene. An angstrom is a unit of length equivalent to one hundred millionth of a centimeter.

These fluctuations, known as intrinsic ripples, have been exceedingly difficult to study because their vertical movement usually creates blurry images, Thibado said. The University of Arkansas researchers successfully produced clear images, enabling them to present a model from elasticity theory to explain the very-low frequency oscillations. In physics, elasticity is the tendency of solid materials to return to their original shape after being deformed.

The researchers’ innovative scanning tunneling microscopy technique provides a much-needed atomic- scale probe for the time-dependent behaviors of intrinsic ripples, said Thibado, an expert in experimental condensed matter physics. The ripple dynamics are important for understanding mechanical stability and the efficient thermal conductivity transport properties of graphene.

In the last decade, theoretical physicists predicted a bending mode in two-dimensional material graphene that couples to a stretching mode of the graphene. Without that bending and coupling, freestanding graphene wouldn’t exist, Thibado said.

This study, funded by the Office of Naval Research and the National Science Foundation, was conducted primarily through a research partnership between the University of Arkansas and the University of Antwerp in Belgium.

The results were obtained through a collaborative effort with University of Arkansas physics graduate students Steven D. Barber, James Kevin Schoelz and Matthew L. Ackerman; Mehdi Neek-Amal of the University of Antwerp and Shahid Rajaee Teacher Training University in Iran, Ali Sadeghi of the University of Basel in Switzerland and Francois Peeters of the University of Antwerp.

CONTACT:
Paul Thibado, professor, physics
J. William Fulbright College of Arts and Sciences
479-575-7932, thibado@uark.edu

Chris Branam | newswise

Further reports about: Arts elasticity fluctuations graphene graphite materials measure physics properties

More articles from Materials Sciences:

nachricht Mat4Rail: EU Research Project on the Railway of the Future
23.02.2018 | Universität Bremen

nachricht Atomic structure of ultrasound material not what anyone expected
21.02.2018 | North Carolina State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>