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 Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside

nachricht New process produces hydrogen at much lower temperature
01.12.2016 | Waseda 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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>