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Growth of disorder of electrons measured in dual temperature system

Date:
August 15, 2013
Source:
Aalto University
Summary:
Researchers have succeeded for the first time in experimentally measuring a probability distribution for entropy production of electrons. Entropy production means an increase in disorder when electrons are moved individually between two microscopic conductors of differing temperatures.
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Researchers at Aalto University, Finland and the University of Tokyo have succeeded for the first time in experimentally measuring a probability distribution for entropy production of electrons. Entropy production means an increase in disorder when electrons are moved individually between two microscopic conductors of differing temperatures.

The researchers also showed that a connection prevails between two definitions of entropy that have been used. The result is significant for the design of future nanoelectronic devices. The study was published recently in the scientific journal Nature Physics.

Similar experiments have been conducted before, but this is the first time the researchers have used conductors at different temperatures to measure the entropy production of electrons.

'Entropy production is defined either by the time when the shift takes place or by the heat that moves from one conductor to another. In the study we measured electronic entropy production according to both definitions. The change in entropy in an individual measurement is random: the distribution for production is acquired by repeating the process about 100,000 times, for instance. Both distributions follow the so-called fluctuation relation', says doctoral student Jonne Koski from Aalto University.

Fluctuation relations are relatively new discoveries of thermodynamics and statistical physics. When the probability to produce a certain amount of disorder of electrons, or entropy, is precisely known, the fluctuation relation is an equation, which gives a probability for the decrease in the amount of entropy. Therefore, the degree of disorder of electrons can decline when the nanostructures are examined for short periods of time.

'Entropy production leads to overheating in the nanostructures, which is why it is important to get more information on their heat transmission properties', says Professor Jukka Pekola.


Story Source:

The above post is reprinted from materials provided by Aalto University. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. V. Koski, T. Sagawa, O-P. Saira, Y. Yoon, A. Kutvonen, P. Solinas, M. Möttönen, T. Ala-Nissila, J. P. Pekola. Distribution of entropy production in a single-electron box. Nature Physics, 2013; DOI: 10.1038/nphys2711

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Aalto University. "Growth of disorder of electrons measured in dual temperature system." ScienceDaily. ScienceDaily, 15 August 2013. <www.sciencedaily.com/releases/2013/08/130815104928.htm>.
Aalto University. (2013, August 15). Growth of disorder of electrons measured in dual temperature system. ScienceDaily. Retrieved September 4, 2015 from www.sciencedaily.com/releases/2013/08/130815104928.htm
Aalto University. "Growth of disorder of electrons measured in dual temperature system." ScienceDaily. www.sciencedaily.com/releases/2013/08/130815104928.htm (accessed September 4, 2015).

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