Laser pulses reveal the superconductors of the future

May 10, 2017
Thanks to innovative laser techniques, a class of materials shows a new potential for energy efficiency. Credit: Pixabay

An experiment at the cutting edge of condensed matter physics and materials science has revealed that the dream of more efficient energy usage can become reality. An international collaboration led by the scientists of Italy's International School for Advanced Studies (SISSA) in Trieste, Università Cattolica di Brescia and Politecnico di Milano used tailored laser pulses to snap the electronic interactions in a compound containing copper, oxygen and bismuth. They were thus able to identify the condition for which the electrons do not repel each other, that is an essential prerequisite for current to flow without resistance. This research opens new perspectives for the development of superconducting materials with applications in electronics, diagnostics and transport. The study has just been published in Nature Physics.

Using sophisticated laser techniques to investigate the so-called non-equilibrium regime, the scientists found an innovative way to understand the properties of a special class of . The SISSA team dealt with the theoretical aspects of the research while the I-LAMP labs of Università Cattolica del Sacro Cuore (Brescia) and Politecnico di Milano coordinated the experimental side.

"One of the greatest obstacles to exploit superconductivity in everyday technology is that the most promising superconductors tend to become insulators at high temperatures and for low doping concentrations," the scientists explained. "This is because the electrons tend to repel each other instead of pairing up and moving in the direction of the current flow." To study this phenomenon, the researchers focused on a specific superconductor with highly complex physical and chemical properties, being composed of four different elements including copper and oxygen. "Using a laser pulse, we drove the material out of its equilibrium state. A second, ultra-short pulse then enabled us to disentangle the components that characterise the interaction between the electrons while the material was returning to equilibrium. Metaphorically, it was like taking a series of snapshots of the different properties of that material at different moments."

Through this approach, the scientists found that "in this material, the repulsion between the electrons, and therefore their insulating properties, disappears even at room temperature. It is a very interesting observation, as this is the essential prerequisite for turning a material into a superconductor." What is the next step in achieving this? "We will be able to take this material as a starting point and change its chemical composition, for example," the researchers explained. Having discovered that the prerequisites for producing a superconductor at exist, scientists now have new tools at their disposal for finding the correct recipe: by changing a few ingredients, they might not be too far away from the right formula.

Its applications? The magnetic field generated by passing a current through a superconductor could be used for a new generation of magnetic levitation trains like the one that already links Shanghai to its airport, featuring far better performance and efficiency. In diagnostics, it would be possible to generate very large magnetic fields in extremely small spaces, thus making it possible to perform high-accuracy magnetic resonance imaging on a very small scale. In the field of energy transport or microelectronics, high-temperature would provide extremely high efficiency and, at the same time, considerable energy savings.

Explore further: Ultrafast laser pulses shed light on elusive superconducting mechanism

More information: S. Peli et al, Mottness at finite doping and charge instabilities in cuprates, Nature Physics (2017). DOI: 10.1038/nphys4112

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rderkis
5 / 5 (1) May 10, 2017
Another breakthrough for fusion? :-)
Dingbone
May 10, 2017
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Mark Thomas
5 / 5 (3) May 10, 2017
"Another breakthrough for fusion?"

Hopefully. Maximum magnetic field strength and manufacturability may be the biggest factors, but this certainly can't hurt by potentially improving operating costs and safety margins at the same time.

Potentially another use is power storage from renewable energy sources, etc. Room temperature superconductors would also make it easier to have magnetic field shielding for spacecraft to reduce damage from radiation.
rderkis
5 / 5 (2) May 10, 2017
Hopefully. Maximum magnetic field strength and manufacturability may be the biggest factors

I could be wrong but it would change everything. Anything that uses superconductors would get much cheaper. MRIs and all superconducting medical equipment. I read once that it would revolutionize battery storage. You could build a powerhouse anywhere and not worry about how far away your base customers are. I think the list goes on and on.
Every time you double the strength of a fusion magnet you cut down the size of the needed structure by 90%.
Soon it will be just a engineering problem to make the magnets structure strong enough to hold it.
If you listen to what MIT says about ARC and SPARC the fusion technology is available now. The engineering is available now. The cost is not billions but millions. And BTW the engineering is such that it can be easily disassembled for upgrading.
Mark Thomas
5 / 5 (2) May 10, 2017
Rderkis, I am hedging a little, but only because I don't know if these new materials will outperform all known superconductors on every measure. However, I agree it could potentially change everything in a very big way. I am encouraged to read that you are aware of the most recent MIT fusion reactor design. I believe their work is excellent and I would love to see their fusion reactor get built and pass up ITER, if only because the human race could really use a break on energy production before mid-century. Room temperature superconductors could potentially go a long way to addressing our global warming problem. I for one am sick of arguing about global warming. Let's just solve the damn problem and get on to bigger and better things like exploring the amazing solar system we live in.
vacuumforce
5 / 5 (1) May 10, 2017
and terraforming mars

hint hint

magnetic shield
rderkis
3 / 5 (2) May 10, 2017
and terraforming mars


While terraforming mars sounds great, I think Humanforming us to live on mars will happen much sooner.

pass up ITER,


From what I understand about the MIT fusion concept, is that it is ITER on a smaller scale physically (less than 1/10) but producing more power and updated with latest technology. That is why they are certain it will work. Plus it is cheaper by a magnitude.
swordsman
1 / 5 (1) May 11, 2017
Electrons not repelling one another? Coulomb's Law repealed? I think not. Misinterpretations.
rderkis
3 / 5 (2) May 11, 2017
Electrons not repelling one another? Coulomb's Law repealed? I think not. Misinterpretations.


I don't know exactly what you mean but I understand the current(pun?) theory is that 2 electrons join(?) each other and travel as a pair through/over a superconductor.
khermerker
not rated yet May 11, 2017
Electrons not repelling one another? Coulomb's Law repealed? I think not. Misinterpretations.

ok.. they are talking about the net force, superconductors are too complex system.. and a lot of interactions happen.. between them and the ions forming the lattice. Is usual think that phonos (vibrations of the lattice) and the interaction of electrons with phonos could bring a net attraction between electrons.. that is eletron interaction by phonos and by coulomb is attractive.

I suggest read about eletron-electron interaction by phonon exchange, but its not the only one that could be possible ..other could be plasmons, etc

I have to add that BCS theory only ask for attraction between electrons .. so this sounds at least interesting.
Dingbone
May 11, 2017
This comment has been removed by a moderator.
antialias_physorg
5 / 5 (2) May 11, 2017
Electrons not repelling one another? Coulomb's Law repealed?

No, Coulomb's law is still applicable. But you have at to look at the whole picture. Electrons aren't moving in free space, here. They are moving within a material where this happens:
https://en.wikipe...per_pair

In essence we're talking about pairs of electrons potentially far apart (i.e. little repulsion to begin with) but where the distortion of the material lattice they are moving in (positive nuclei) causes this residual repulsion to be cancelled out. So they act as if they are bound to one another (i.e. no repulsion)
Da Schneib
5 / 5 (2) May 11, 2017
Basically the idea is that each free electron creates a distortion in the lattice around it as it moves through the superconducting substrate; this distortion propagates through the lattice as the electron moves. At the right distance apart, two such distortions can result in an attraction, which is stronger than the Coulomb force between the electrons. This attraction is present only at certain distances, determined by the inter-atomic forces in the lattice, which are in turn determined by the exact composition of the lattice.

As the temperature increases, these distortions become overwhelmed by thermal noise in the lattice. How much this affects the phenomenon depends on a lot of variables. What these guys are looking for is a material that can serve as a substrate when it is at room temperature.

We can discuss what all these variables are if you're curious.
Dingbone
May 11, 2017
This comment has been removed by a moderator.
Da Schneib
5 / 5 (1) May 11, 2017
@Dingtroll, sorry if you don't have the imagination to see why.

Maybe you should learn some integral calculus which you could then deny.

From a graphical perspective, consider the interaction of two phonons, each propagating from the two distortions in the lattice created by the Cooper pair. At some given distance, they will form an attractive interaction exactly offsetting the Coulomb repulsive interaction; at this distance, which is controlled by the attributes of the lattice, if the attractive force is equal to the Coulomb force, the two electrons will be formed into a pair and will move through the lattice with zero resistance.

This is pretty much how superconductivity works. You might want to study it instead of denying it. Just sayin'.
antialias_physorg
5 / 5 (1) May 11, 2017
Rather than type it out here's a vidoe explaining it
https://www.youtu...oQcljFOs
rderkis
1 / 5 (1) May 11, 2017
This is very easy to say - but how can distortion of lattice lead into an attraction?


How dare you ask a question of a lot of Trolls? (Unless you have already muted/ignored them)

I will guarantee you will get answers back that are clocked in demeaning or bullying words. I suggest you mute/ignore the person sending it. But only if you have the strength of character not to peek at and then answer their comments. :-)
Da Schneib
5 / 5 (1) May 11, 2017
Mmmmhhhh, @antialias, he kinda avoids the part about the two lattice distortions forming an attraction that's greater than the Coulomb repulsion. Not bad, but not complete.
Dingbone
May 12, 2017
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Dingbone
May 12, 2017
This comment has been removed by a moderator.
Dingbone
May 12, 2017
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