Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Diverging thermal conductivity


Physicists at the Max Planck Institute for Polymer Research show unlimited heat conduction in graphene.

Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz and the National University of Singapore have attested that the thermal conductivity of graphene diverges with the size of the samples. This discovery challenges the fundamental laws of heat conduction for extended materials.

Davide Donadio, head of a Max Planck Research Group at the MPI-P, and his partner from Singapore were able to predict this phenomenon with computer simulations and to verify it in experiments. Their research and their results have now been presented in the scientific journal "Nature Communications".

"We recognized mechanisms of heat transfer that actually contradict Fourier’s law in the micrometer scale. Now all the previous experimental measurements of the thermal conductivity of graphene need to be reinterpreted. The very concept of thermal conductivity as an intrinsic property does not hold for graphene, at least for patches as large as several micrometers", says Davide Donadio.

Are material constants alterable after all?

The French physicist Joseph Fourier had postulated the laws of heat propagation in solids. Accordingly, thermal conductivity is an intrinsic material property that is normally independent of size or shape. In graphene, a two-dimensional layer of carbon atoms, it is not the case, as our scientists now found out. With experiments and computer simulations, they found that the thermal conductivity logarithmically increases as a function of the size of the graphene samples: i.e., the longer the graphene patches, the more heat can be transferred per length unit.

This is another unique property of this highly praised wonder material that is graphene: it is chemically very stable, flexible, a hundred times more tear-resistant than steel and at the same time very light. Graphene was already known to be an excellent heat conductor: The novelty here is that its thermal conductivity, which was so far regarded as a material constant, varies as the length of graphene increases. After analyzing the simulations, Davide Donadio found that this feature stems from the combination of reduced dimensionality and stiff chemical bonding, which make thermal vibration propagate with minimal dissipation at non-equilibrium conditions.

Optimum cooling for nanoelectronics

In the micro- and nano-electronics, heat is the limiting factor for smaller and more efficient components. Therefore, materials with virtually unlimited thermal conductivity hold an enormous potential for this kind of applications. Materials with outstanding electronic properties that are self-cooling too, as graphene might be, are the dream of every electronics engineer.

Davide Donadio, an Italian-born researcher, already dealt with nanostructures of carbon, crystallization processes and thermoelectric materials during his studies in Milan, his research stays at the ETH Zurich (Switzerland) and at the University of California, Davis (USA). Since 2010, he has been investigating, among others, thermal transport in nanostructures using theoretical physics and simulating the atomic behavior of substances with his Max Planck Research Group at the MPI-P.

Weitere Informationen: - the press release and original publication - informatio about Davide Donadio and his research - Max Planck Institute for Polymer Research

Stephan Imhof | Max-Planck-Institut

More articles from Physics and Astronomy:

nachricht Listening to the Extragalactic Radio
13.10.2015 | Max-Planck-Institut für Radioastronomie

nachricht Scientists paint quantum electronics with beams of light
12.10.2015 | University of Chicago

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Secure data transfer thanks to a single photon

Physicists of TU Berlin and mathematicians of MATHEON are so successful that even the prestigious journal “Nature Communications” reported on their project.

Security in data transfer is an important issue, and not only since the NSA scandal. Sometimes, however, the need for speed conflicts to a certain degree with...

Im Focus: A Light Touch May Help Animals and Robots Move on Sand and Snow

Having a light touch can make a hefty difference in how well animals and robots move across challenging granular surfaces such as snow, sand and leaf litter. Research reported October 9 in the journal Bioinspiration & Biomimetics shows how the design of appendages – whether legs or wheels – affects the ability of both robots and animals to cross weak and flowing surfaces.

Using an air fluidized bed trackway filled with poppy seeds or glass spheres, researchers at the Georgia Institute of Technology systematically varied the...

Im Focus: Reliable in-line inspections of high-strength automotive body parts within seconds

Nondestructive material testing (NDT) is a fast and effective way to analyze the quality of a product during the manufacturing process. Because defective materials can lead to malfunctioning finished products, NDT is an essential quality assurance measure, especially in the manufacture of safety-critical components such as automotive B-pillars. NDT examines the quality without damaging the component or modifying the surface of the material. At this year's Blechexpo trade fair in Stuttgart, Fraunhofer IZFP will have an exhibit that demonstrates the nondestructive testing of high-strength automotive body parts using 3MA. The measurement results are available in a matter of seconds.

To minimize vehicle weight and fuel consumption while providing the highest level of crash safety, automotive bodies are reinforced with elements made from...

Im Focus: Kick-off for a new era of precision astronomy

The MICADO camera, a first light instrument for the European Extremely Large Telescope (E-ELT), has entered a new phase in the project: by agreeing to a Memorandum of Understanding, the partners in Germany, France, the Netherlands, Austria, and Italy, have all confirmed their participation. Following this milestone, the project's transition into its preliminary design phase was approved at a kick-off meeting held in Vienna. Two weeks earlier, on September 18, the consortium and the European Southern Observatory (ESO), which is building the telescope, have signed the corresponding collaboration agreement.

As the first dedicated camera for the E-ELT, MICADO will equip the giant telescope with a capability for diffraction-limited imaging at near-infrared...

Im Focus: Locusts at the wheel: University of Graz investigates collision detector inspired by insect eyes

Self-driving cars will be on our streets in the foreseeable future. In Graz, research is currently dedicated to an innovative driver assistance system that takes over control if there is a danger of collision. It was nature that inspired Dr Manfred Hartbauer from the Institute of Zoology at the University of Graz: in dangerous traffic situations, migratory locusts react around ten times faster than humans. Working together with an interdisciplinary team, Hartbauer is investigating an affordable collision detector that is equipped with artificial locust eyes and can recognise potential crashes in time, during both day and night.

Inspired by insects

All Focus news of the innovation-report >>>



Event News

EHFG 2015: Securing healthcare and sustainably strengthening healthcare systems

01.10.2015 | Event News

Conference in Brussels: Tracking and Tracing the Smallest Marine Life Forms

30.09.2015 | Event News

World Alzheimer`s Day – Professor Willnow: Clearer Insights into the Development of the Disease

17.09.2015 | Event News

Latest News

Smart clothing, mini-eyes, and a virtual twin – Artificial Intelligence at ICT 2015

13.10.2015 | Trade Fair News

Listening to the Extragalactic Radio

13.10.2015 | Physics and Astronomy

Penn study stops vision loss in late-stage canine X-linked retinitis pigmentosa

13.10.2015 | Health and Medicine

More VideoLinks >>>