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.
http://www.mpip-mainz.mpg.de/news/thermal_conductivity - the press release and original publication
http://www.mpip-mainz.mpg.de/theory_nanostructures - informatio about Davide Donadio and his research
http://www.mpip-mainz.mpg.de/home/en - Max Planck Institute for Polymer Research
Stephan Imhof | Max-Planck-Institut
Spiral arms: not just in galaxies
30.09.2016 | Max-Planck-Institut für Radioastronomie
Discovery of an Extragalactic Hot Molecular Core
29.09.2016 | National Astronomical Observatory of Japan
Heavy construction machinery is the focus of Oak Ridge National Laboratory’s latest advance in additive manufacturing research. With industry partners and university students, ORNL researchers are designing and producing the world’s first 3D printed excavator, a prototype that will leverage large-scale AM technologies and explore the feasibility of printing with metal alloys.
Increasing the size and speed of metal-based 3D printing techniques, using low-cost alloys like steel and aluminum, could create new industrial applications...
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of light metals.
Scientists at the University of Stuttgart have now developed two new process variants that will considerably expand the areas of application for friction stir welding.
Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations.
Friction stir welding is a still-young and thus often unfamiliar pressure welding process for joining flat components and semi-finished components made of...
Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.
Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...
The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.
“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...
With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.
Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...
30.09.2016 | Event News
29.09.2016 | Event News
28.09.2016 | Event News
30.09.2016 | Materials Sciences
30.09.2016 | Earth Sciences
30.09.2016 | Life Sciences