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Researchers have proven a superconductor previously thought impossible



New type of superconductivity has been discovered

Polarized light images show researchers how electrons, represented by red crosses, in their test samples perform under different circumstances. Credit: © 2020 Okazaki et al.

Superconductivity is a phenomenon in which a circuit loses resistance and becomes extremely effective under certain conditions. There are different ways this can happen, which are supposedly incompatible. Researchers have discovered a bridge between two of these methods for the first time to achieve superconductivity. This new knowledge may lead to a more general understanding of the phenomenon and one day its application.


There are three well-known states of matter: solid, liquid and gas. There is a fourth state of matter called plasma, which is like a gas so hot that all of its constituent atoms are split apart, leaving a super-hot mess of subatomic particles. But there is a fifth physical state at the completely opposite end of the thermometer known as the Bose-Einstein condensate (BEC).

“BEC is a single state of matter because it is not made of particles but waves,”

; said Associate Professor Kozo Okazaki from the Institute of Solid State Physics at the University of Tokyo. “As they cool to near absolute zero, the atoms of certain materials become smeared in space. This stains increase until the atoms – now more like waves than are particles – superimposed, becoming indistinguishable from each other.one-single entity with new properties that previous solid, liquid, or gas states lacked, such as superconductivity. Superconductivity is only theoretical, but we have now demonstrated this in the lab with a new material based on iron and selenium (a non-metallic element). “

This is the first time that a BEC has been experimentally verified to act as a superconductor; however, other manifestations of matter, or mode, can also give rise to superconductivity. The Bardeen-Cooper-Shrieffer (BCS) mode is an arrangement of matter such that when cooled to near absolute zero, the constituent atoms slow down and line up, allowing electrons to pass easily. than. This effectively makes the resistance of such materials zero. Both BCS and BEC require freezing conditions and both are involved in the activity of atoms slowing down. But the modes are completely different. Researchers have long believed that a more general understanding of superconductivity can be obtained if the regimes can be found overlapping in some way.

New type of superconductivity has been discovered

These colorful lines are not just for display, they tell researchers under what temperature, in this case about 10 kelvin, a pattern exhibiting superconducting behavior. Credit: © 2020 Okazaki et al.

“Proving the BEC’s superconductivity is a means to an end; we really hope to discover the overlap between the BEC and the BCS,” Okazaki said. “It’s incredibly challenging but our unique apparatus and method of observation confirm that – there’s a smooth transition between these modes. And this suggests a total fundamental theory. More general behind superconductivity. This is an exciting time to work in this field.

Okazaki and his team used laser emission spectroscopy based on extremely low temperature and high energy resolution to observe how electrons behave in the transition of materials from BCS. to BEC. Electrons behave differently in the two modes, and the change between them helps fill some of the gaps in the larger picture of superconductivity.

Superconductivity is not just about laboratory curiosity, though; Superconducting devices such as electromagnets have been used in applications, the Large Hadron Collider, the world’s largest particle accelerator, is one such example. However, as explained above, these require supercooling temperatures to prevent the development of superconducting devices that we can expect to see on a daily basis. Therefore, it is not surprising that much attention is being paid to finding a way to form superconductors at higher temperatures, maybe even room temperature a day.

“With the convincing evidence of superconducting BECs, I think it will motivate other researchers to discover superconductivity at ever higher temperatures,” Okazaki said. “Right now sounds like science fiction, but if superconductivity can happen near room temperature, our energy production capacity will greatly increase and their energy needs. I will decrease. ”


Laser light forces the iron compound to conduct electricity without resistance


More information:
Hashimoto et al., Bose-Einstein condensation superconductivity is caused by the disappearance of the nematic state. Scientific advance (Year 2020). DOI: 10.1126 / sciadv.abb9052

Provided by University of Tokyo

Quote: Researchers demonstrated a previously thought impossible superconductor (2020, November 6) retrieved November 7, 2020 from https://phys.org/news/2020-11 -superconductor-previous-thought-impossible.html

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