Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Physicists Heat Freestanding Graphene to Control Curvature of Ripples


Discovery represents advance in understanding of conductive material

An international team of physicists, led by a research group at the University of Arkansas, has discovered that heating can be used to control the curvature of ripples in freestanding graphene.

Mehdi Neek-Amal, University of Antwerp

Height of the initial buckled graphene state with the bias voltage set to 3 V and the central temperature set to 300 K.

The finding provides fundamental insight into understanding the influence temperature exerts on the dynamics of freestanding graphene. This may drive future applications of the flexible circuits of consumer devices such as cell phones and digital cameras.

While freestanding graphene offers promise as a replacement for silicon and other materials in microprocessors and next-generation energy devices, much remains unknown about its mechanical and thermal properties.

The research team published its findings on Wednesday, Sept. 17, in a paper titled “Thermal mirror buckling in freestanding graphene locally controlled by scanning tunneling microscopy” in the online journal Nature Communications, a publication of the journal Nature.

Previously, scientists have used electric voltage to cause large movements and sudden changes in the curvature of the ripples in freestanding graphene, said Paul Thibado, professor of physics at the University of Arkansas. In this paper, the team showed that an alternative method, thermal load, can be used to control these movements.

“Imagine taking a racquetball and cutting it in half,” said Thibado, an expert in experimental condensed matter physics. “You could invert it by pressing on it. That’s what we did here with a cross-section of a single ripple of freestanding graphene at the nanometer scale. Most materials expand when you heat them. Graphene contracts which is very unusual. So when we heated this cross-section, instead of expanding, it contracted, and that thermal stress caused it to buckle in the opposite direction.”

Graphene, discovered in 2004, is a one-atom-thick sheet of graphite. Electrons moving through graphite have mass and encounter resistance, while electrons moving through graphene are massless, and therefore travel much more freely. This makes graphene an excellent candidate material for use in meeting future energy needs and the fabrication of quantum computers, which make enormous calculations with little energy use.

The study was led by Peng Xu, formerly a postdoctoral research associate in the Department of Physics at the University of Arkansas and currently a postdoctoral research associate at the University of Maryland.

Xu and Thibado used scanning tunneling microscopy, which produces images of individual atoms on a surface, combined with large-scale molecular dynamic simulations to demonstrate the thermal mirror buckling.

In the paper, the third published in a major journal by the research team in 2014, they propose a concept for a new instrument that capitalizes on the control of the mirror buckling: a nanoscale electro-thermal-mechanical device.

Such a device would provide an alternative to microelectromechanical systems, which are tiny machines that are activated electrically. The advantage of this nanoscale electro-thermal-mechanical device would be the ability to change its output using electricity or heat. In addition, thermal loads can provide a significantly larger force.

The 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.

Paul Thibado, professor, physics
J. William Fulbright College of Arts and Sciences

Chris Branam | newswise

More articles from Materials Sciences:

nachricht How nanoscience will improve our health and lives in the coming years
27.10.2016 | University of California - Los Angeles

nachricht 3-D-printed structures shrink when heated
26.10.2016 | Massachusetts Institute of Technology

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 light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

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

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Steering a fusion plasma toward stability

28.10.2016 | Power and Electrical Engineering

Bioluminescent sensor causes brain cells to glow in the dark

28.10.2016 | Life Sciences

Activation of 2 genes linked to development of atherosclerosis

28.10.2016 | Life Sciences

More VideoLinks >>>