Report of room-temperature superconductor sets scientific community alight
The scientific community was abuzz in July after a South Korean team from the Quantum Energy Research Center uploaded a paper to arXiv claiming to have discovered a room-temperature superconductor they dubbed LK-99. If confirmed, the find would be monumental. Superconductivity – the transmission of electricity with no energy loss – has only been found to occur at temperatures near absolute zero or at extremely high pressures. An easily accessible room-temperature superconductor, particularly one made from cheap materials as LK-99 was, would be like bringing CERN to everyone’s living rooms.
As is usually the case with things that seem too good to be true, LK-99 was. Red flags appeared immediately. The first was that Young-Wan Kwon, the former CTO of the research center who had since departed, first uploaded a paper titled “The First Room-Temperature Ambient-Pressure Superconductor.” Kwon was at the center during most of LK-99’s development but left in March. The hasty posting of that paper prompted Sukbae Lee and Jihoon Kim (the L and K that give LK-99 its name) to post their own version, “Superconductor Pb10-xCux(PO4)6O showing levitation at room temperature and atmospheric pressure and mechanism.”
While a computer simulation by Lawrence Berkeley National Laboratory physicist Sinead Griffin gave some hope that LK-99 could in fact be a superconductor, real-world tests soon proved otherwise.
In addition to its seeming superconductivity, LK-99 appeared to levitate in a video Lee and Kim posted on social media. Researchers all over the world began putting together their own samples of LK-99 – made from copper, lead, phosphorous, and oxygen – and began conducting their own experiments.
A few, including scientists at China’s International Center for Quantum Materials, concluded that LK-99 is experiencing ferromagnetism, a phenomenon in which electrically uncharged materials strongly attract others. Derrick VanGennep, a former condensed-matter researcher at Harvard, pointed out that superconductors levitating over magnets can be spun or held upside-down, whereas the video of LK-99 showed it seemingly sticking to a magnet. Peking University researchers called it “half-levitation” due to ferromagnetism, Nature reported.
So not only is LK-99 not a room-temperature superconductor, the Condensed Matter Theory Center at the University of Maryland found its resistivity to be a billion times higher than copper. “LK99 seems to be an Anti-SC,’ the center concluded.
“I think things are pretty decisively settled at this point,” Inna Vishik, a condensed-matter experimentalist at the University of California, Davis, told Nature.
Why, then, did the Quantum Energy Research Center team think LK-99 had superconductive abilities? University of Illinois chemist Prashant Jain concluded it was because of impurities, particularly copper sulfide.
“They were very precise about it: 104.8º C,” Jain told Nature. “I was like, wait a minute, I know this temperature.”
At 104º C, copper sulfide transitions phases and its resistivity changes. “I was almost in disbelief that they missed it,” Jain said.
All signs point to LK-99 not being a room-temperature superconductor. That’s a shame, because such a discovery would change so many things about the world as we know it. Being able to bring resistance close to zero would make our electric grids 10-15% more efficient. It would help build super-fast quantum computers and make it cheap to build high-speed magnetic levitation trains.
“The sky is the limit here,” Giuseppe Tettamanzi of the University of Adelaide’s school of chemical engineering told CNET.
So researchers will continue the search for a room-temperature superconductor. With all the attention and experimentation the LK-99 saga brought, it could plant the seed of a new search method that bears fruit.
LK-99 isn’t the answer, but one could still be out there, waiting to be discovered.