Electron ‘dance’ could lead to room-temperature superconductors

Considered the “holy grail” of contemporary physics Superconducting materials have revealed some extraordinary properties in the last centuryThe most important of these is the ability to conduct electricity without any electrical resistance, which points to some revolutionary applications, such as magnetic levitation trains.

The problem that researchers are constantly working on is, Is this superconductivity? currently only works at extremely low temperaturesThe biggest challenge in this sense is to find materials that offer their unique properties at higher temperatures or even at room temperature.

Recently, an international team led by researchers from the SLAC National Accelerator Laboratory at Stanford University in the USA noted in a study published in the journal Science that electron pairing, a necessary property of a superconductor, can be achieved at much lower temperatures than previously thought and made of an unusual material: an antiferromagnetic insulator.

Synchronized “dance” of electrons

Although an electrical insulator might not seem like a material that would be conducive to superconductivity, the team detected electron pairs at temperatures as low as -123°C, one of the requirements for lossless flow. “The electron pairs tell us that they are ready to become superconductors, but something is stopping them“, jokes the paper’s first author Ke-Jun Xu in a statement.

The question now, says the physics graduate student, is to discover a new method to synchronize these pairs. Over the years, researchers have learned that for a material to be superconducting, it is not enough for the electrons to be paired, they also need to be coherent. This means that their movements must be synchronized, otherwise the material becomes an insulator.

In the press release, SLAC science communications officer David Krause likens the behavior of electrons to two people at a party who get together and start dancing when they hear the DJ play a song they both like. Then, Other electrons also start to form pairs and make the party superconductingThe engineer says that in the current study, the electrons were just flirting but not trying to dance.

Testing electron pairing in cuprates

Conventional superconductors operate at temperatures near absolute zero (-273.15 °C), but in materials known as unconventional superconductors, electrons pair and dance simultaneously at much higher temperatures. In this particular class of materials, something other than lattice vibrations is causing the electrons to pair, but researchers don’t know why.

In the current study, the authors bet on a family. unconventional superconductors have been little studied They are called “cuprates.” The team proved that the electrons resisted sputtering by shining ultraviolet light on the material, resulting in an “energy gap” that remained up to 150 Kelvin, which is evidence that the electrons couple at temperatures higher than zero resistance, up to almost 25 Kelvin.

Paradoxically, the coupling was stronger in more isolating samples. The next step is to test this coupling gap in new families of superconductors..

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