Scientists Just Discovered A Brand-New Superconductor That Could Change the Game

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• One of the things that makes graphene so special is that it can turn into a superconductor when super-thin sheets of it are stacked on top of each other in a twisted moiré pattern.

• For some time, scientists thought it was unique in that way. But now, tungsten diselenide has been proven to do the same as graphene—and is even more effective.

• Activating superconduction requires extreme cold and pressure, but future research into the properties that make it possible may lead to a room-temperature superconductor someday

In the world of high-fashion, there’s a specific texture of fabric called moiré. Typically made from silk, this textile has a warped visual effect that is achieved by applying heat and pressure rollers until it looks almost like ripples on a pond. In physics and math, rippling moiré patterns can appear as a result of everything from simple geometric crosshatching to interference. And that same effect has now created a new form of superconductor.

Superconductors are so special because they can conduct electricity without resistance. This property can be gained by certain materials through exposure to extreme cold or pressure, and while only a few materials are capable of going superconductive in the first place, one more has now been added to that short and valuable list. A team of researchers led by physicist Cory Dean of Columbia University have found that ultrathin sheets of tungsten diselenide—layered in a twisted moiré arrangement—take on superconducting powers when cooled to temperatures hovering just above absolute zero.

Dean had previously attempted a similar moiré experiment with sheets of graphene (a substance made of pure carbon that is extracted from graphite), which showed signs of superconductivity in a moiré pattern. However, after the graphene structure was cooled below a certain temperature, the electrically conductive areas of the structure went inactive, and any potential superconductivity disappeared.

That was in 2018, and in the years since, Dean and his team have repeatedly tried to figure out how to get graphene to the ideal temperature for superconductivity while keeping its electrically conductive areas alive. Other materials arranged the same way also showed some promising properties—including strange versions of magnetism and electrical insulation—but fell short of turning superconductive. Then, the team decided to try tungsten diselenide.

Tungsten and selenium are both transition metal dichalcogenides (TMDs)—a new group of two-dimensional materials that can become superconductors. Unlike graphene, they have a direct band gap, meaning that their valance bands (the outermost electron shells of atoms) are directly aligned with the conduction band (the electron shell adjacent to the valence band). The direct band gap in tungsten diselenide allows for electrons to easily transition from the valence band to the conduction band. Once in the conduction band, electrons are available for conduction (or superconduction) right away.

“Although a wide range of [superconductor] correlated phenomena have indeed been observed in the moiré TMDs, robust demonstration of superconductivity has remained absent,” the researchers said in a study recently published in the journal Nature.

As graphene is no longer the only material that turns into a superconductor when arranged in a moiré structure, Dean and his team want to probe further into whether or not other TMDs gain superconductive properties from this arrangement that did not show up in any other form.

TMDs have many uses (from transistors to optoelectronics to energy storage) and even have potential for future use in biomedical imaging. The only downside has been the temperature—keeping materials near absolute zero is expensive and incredible energy-intensive. If a room-temperature superconductor is discovered, it would mean being able to transmit unlimited amounts of energy over incredible distances, but no experiments trying to produce one have yet succeeded.

While the exact properties that make tungsten diselenide a superconductor are still unknown, finding out what they are could give scientists an idea of how to maintain the state at higher temperatures—maybe even room temperature.

Who said physics couldn’t be fashionable?

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