Researchers from IBM conducted a measurement of thermal conductivity through a monatomic contact

The system with which the measurements were taken

Experts from the IBM Zurich Research Laboratory were able to obtain experimental evidence of the possibility of isolating and measuring a single quantum of heat. Looking ahead, we can say that the results of the experiment, most likely, will help engineers and scientists to overcome problems with the efficiency of heat removal from elements of modern electronic devices. As for the experiment itself, the scientists managed to measure the thermal conductivity of individual metal atoms - in this case, gold. For the first time in the history of science, scientists were able to successfully conduct a similar experiment at room temperature.

For the first time, researchers from the California Institute of Technology in 1999 made an attempt to measure the thermal conductivity of individual atoms. The experiment was also considered successful, but the measurements were carried out at ultra-low temperatures. Then scientists could experimentally confirm the validity of the Wiedemann-Franz law. This is a physical law, which states that for metals, the ratio of thermal conductivity (or thermal conductivity tensor) to electrical conductivity (or conductivity tensor) is proportional to temperature.

Thanks to this result, specialists can now predict thermal and electrical effects at the subatomic level or within a single molecule.
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“Despite the fact that the law itself was formulated, and it turned out to be fair for certain metals, it was hard to prove its fairness when switching to the nano level,” explains Bernd Gostmann, one of the leading researchers of the work.

In order to successfully conduct measurements at the subatomic level, we need reliable tools. But to create them for obvious reasons is quite difficult. However, last year, scientists from the IBM Zurich Research Lab in partnership with specialists from the Swiss Technical School of Zurich (Eidgenössische Technische Hochschule Zürich) developed and patented the appropriate technology. With its help, it was possible to create a system that can measure the temperature of objects with a size of 10 nanometers or less. The technology is called "scanning probe thermometry." The practical benefit here is that with this equipment you can create a heat distribution map for the electronic part. And this, in turn, opens up the possibility of designing elements that are effectively cooled.



However, 10 nanometers by modern standards is already a resolution for equipment. Therefore, scientists have created a tool that can measure the thermal conductivity of individual atoms, as mentioned above.

Success has been made possible by two key factors. The first is a microelectromechanical system with an integrated thermal sensor, which operates within a vacuum scanning tunneling electron microscope. The electrode with which the measurements are carried out is isolated from the thermal influence of the chip environment.

“In our work, we proved the correctness of the Wiedemann-Franz law in relation to quantum point contacts, which was predicted by IBM scientist Rolf Landauer,” said one research participant. Thanks to the work of scientists from the IBM Research Lab in Zurich, experts can now control the distribution of heat in devices the size of one or more molecules. And this opens up tremendous opportunities for electronics, materials science and other areas of science and technology.