Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wandering heat: Anomalous heat distribution in one-dimensional systems

12.02.2014
According to Fourier’s law, heat spreads evenly throughout a system. For two- and one-dimensional objects such as films or the finest of wires, however, other rules seem to apply. NIM scientists have now pinned these down.

Just as ember spreads through a piece of coal, heat principally diffuses at a constant rate. The corresponding physical law known as Fourier’s law was already established 200 years ago.


Uniform spreading of heat ceases in low dimensions

Later, scientists came to the conclusion that other rules must apply to the distribution of heat in two- or one-dimensional objects such as films or very fine wires. Respective evidence was provided, for example, by experiments with carbon nanotubes or organic molecular chains, where thermal conductivity was not only dependent on the object’s material but also on its size, or rather its length.

This means that in some materials thermal conductivity increases with the object’s length, while in others it decreases. However, no one has so far been able to derive a physical law similar to Fourier’s law from these observations.

Together with international colleagues, NIM physicist Prof. Peter Hänggi (University of Augsburg) and his team have now gone one step further in the quest for such a law. The scientists have for the first time established a universally valid mathematical connection between object-size-dependent thermal conductivity and the corresponding anomalous rate of heat diffusion.

The insights thus gained allow scientists to devise hybrid materials which display entirely new thermal properties in one- or two-dimensional form. They exploit the fact that in these cases the rate of heat diffusion can be very high in some material compositions and extremely low in others. This is to say that one material allows heat to travel through it very quickly, while another functions as thermal insulator. The theoretical calculations are of particular interest for objects at nanoscale, whose thermal behavior is hard to measure in experiments. Currently, nanostructures composed of carbon materials which are to serve as phononic diodes or heat storage systems (memory) are simulated by computer models. Analogous to electronic components, these elements can then be used to conduct information processing.

“The exploration of heat diffusion in low-scale dimensions is only just beginning and certainly holds many surprises – as well as a huge potential”, explains Peter Hänggi. “The ubiquitous detrimental thermal losses, for example, can be used to beneficial effect for functional materials or phononic information processing. Maybe, in the distant future, the dream of a computer functioning with waste heat will come true.”

Publication:

Anomalous Heat Diffusion by Sha Liu, Peter Hänggi, Nianbei Li, Jie Ren, and Baowen Li. Phys. Rev. Lett. 112: 040601 (2014)

http://prl.aps.org/abstract/PRL/v112/i4/e040601

Contact person:

Prof. Peter Hänggi
Chair of Theoretical Physics I
Institute of Physics
University of Augsburg
86135 Augsburg, Germany
Tel: +49 821 598-3250
Hanggi@physik.uni-augsburg.de

Klaus P. Prem | idw
Further information:
http://www.nano-initiative-munich.de
http://www.uni-augsburg.de

More articles from Physics and Astronomy:

nachricht Superconductivity: footballs with no resistance
09.02.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht A deep look into a single molecule
09.02.2016 | Physikalisch-Technische Bundesanstalt (PTB)

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: New study: How stable is the West Antarctic Ice Sheet?

Exceeding critical temperature limits in the Southern Ocean may cause the collapse of ice sheets and a sharp rise in sea levels

A future warming of the Southern Ocean caused by rising greenhouse gas concentrations in the atmosphere may severely disrupt the stability of the West...

Im Focus: Superconductivity: footballs with no resistance

Indications of light-induced lossless electricity transmission in fullerenes contribute to the search for superconducting materials for practical applications.

Superconductors have long been confined to niche applications, due to the fact that the highest temperature at which even the best of these materials becomes...

Im Focus: Wbp2 is a novel deafness gene

Researchers at King’s College London and the Wellcome Trust Sanger Institute in the United Kingdom have for the first time demonstrated a direct link between the Wbp2 gene and progressive hearing loss. The scientists report that the loss of Wbp2 expression leads to progressive high-frequency hearing loss in mouse as well as in two clinical cases of children with deafness with no other obvious features. The results are published in EMBO Molecular Medicine.

The scientists have shown that hearing impairment is linked to hormonal signalling rather than to hair cell degeneration. Wbp2 is known as a transcriptional...

Im Focus: From allergens to anodes: Pollen derived battery electrodes

Pollens, the bane of allergy sufferers, could represent a boon for battery makers: Recent research has suggested their potential use as anodes in lithium-ion batteries.

"Our findings have demonstrated that renewable pollens could produce carbon architectures for anode applications in energy storage devices," said Vilas Pol, an...

Im Focus: Automated driving: Steering without limits

OmniSteer project to increase automobiles’ urban maneuverability begins with a € 3.4 million budget

Automobiles increase the mobility of their users. However, their maneuverability is pushed to the limit by cramped inner city conditions. Those who need to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Travel grants available: Meet the world’s most proficient mathematicians and computer scientists

09.02.2016 | Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

From intelligent knee braces to anti-theft backpacks

26.01.2016 | Event News

 
Latest News

Travel grants available: Meet the world’s most proficient mathematicians and computer scientists

09.02.2016 | Event News

Body temperature triggers newly developed polymer to change shape

09.02.2016 | Materials Sciences

Using renewable energy in heating networks more efficiently

09.02.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>