Posted in | Quantum Physics

Study Sheds Light on the Atomic Causes of High-Temperature Superconductivity

Superconductors are expected to redefine the energy industry in the near future, but for this to be happen, these materials should have the ability to transport electricity under room temperature without any kind of resistance.

The research team at the University of Bayreuth: Dr Thomas Meier, Professor Dr Leonid Dubrovinsky, Professor Dr Natalia Dubrovinskaia, Timofey Fedotenko M.Sc., Saiana Khandarkhaeva M.Sc., PD Dr Gerd Steinle-Neumann, Florian Trybel M.Sc., Dr Sylvain Petitgirard (from left to right). (Image credit: Christian Wißler)

The fact that metal hydrides are different from other superconductors is that they do not have this potential only at extreme coldness, but also at deep fridge temperatures. This is induced by atomic processes, which have been revealed by researchers from the University of Bayreuth for the first time.

The results of the study published in “Physical Review X” contain useful points of departure for developing superconductors that are technologically attractive.

Over the last five years, not many scientists have effectively used extremely high pressures to create hydrogen-rich metal hydrides, which turn out to be superconductive at deep fridge temperatures (about –20 °C).

Hence, this so-called transition temperature of metal hydrides is much higher than that of other materials which turn out to be superconductive only at –200 °C. For a long time, it was not known what exactly causes metal hydrides to behave in a different way.

Now, the researchers from the Laboratory of Crystallography at the University of Bayreuth and from the Bavarian Geoinstitute (BGI) have described hypothetically and demonstrated experimentally that in metal hydrides, hydrogen atoms begin to interact with one another at high pressures. This information could provide a better insight into the superconductive state as well as its origin.

We now have a valuable starting point for the design of metal hydrides which become possibly superconductive at even higher temperatures. With new technology of high-pressure research in the Bavarian Geoinstitute, we can synthesize these materials and check our predictions directly on site empirically.

Dr Thomas Meier, Team Lead, University of Bayreuth

Dr Meier continued, “The measurements under high pressure will have, in turn, an impact on our theoretical assumptions. Thereby they allow increasingly exact predictions of the atomic processes which put metal hydrides into a superconductive state.

The Bayreuth team’s vision reaches far into the future:

Predicated on the interplay of empiric measurements and theoretical predictions, the researchers want to produce innovative materials and thus accomplish transition temperatures, which reach closer to usual ambient temperatures.

It has been predicted that these new materials can make a decisive impact on electric energy transport in the near future. Despite this, one more obstacle still needs to be taken—the metal hydrides, which have become superconductive to date, have this potential as long as the extreme degree of compression continues under which they have originated.

The materials will disintegrate once the pressure reduces. However, superconductors are considered an attractive option for technological applications only if they prove to be stable under standard conditions.

The results of the study on atomic processes in metal hydrides—which have been currently published—can only be realized. This is because the Bayreuth team has integrated two research technologies—that is, nuclear magnetic resonance spectroscopy (NMR), and producing high-pressure as it is known from the materials physics and geosciences.

To realize this combination, the Bavarian Geoinstitute of the University of Bayreuth was chosen in 2018 as one among “100 excellent places in the country of the ideas.”

Thanks to the synergy of the high-pressure research know-how collected in the University of Bayreuth and the NMR proficiency of Dr Thomas Meier, these research technologies could ultimately be brought together.

Source: https://www.uni-bayreuth.de/en/

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