November 25, 2024

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A screen capture from a YouTube video describing superconductivity provided by Kim Hyun-tak, who was part of the Korean team researching superconductor technology and a research professor of physics at the College of William and Mary in Virginia (Kim Hyun-tak’s YouTube)

The Korean Society of Superconductivity and Cryogenics’ review committee on Wednesday said LK-99, an alleged room-temperature superconductor created by a South Korean research team, has not shown any key features of superconductivity.

“There is no ground for saying that LK-99 is a superconductor,” the committee said in a report, stressing that it showed no signs of superconductivity in a series of tests on resistance and magnetic susceptibility in either room- or low temperatures.

Another test that removed impurities on the re-created single crystal samples proved that the so-called superconductor is a "nonconductor" that does not allow electricity to pass through, it added.

If LK-99 was a superconductor, it had to show zero resistance, transmitting electricity without losing energy. When a scientist applies a magnetic field, it should create its own equal and opposite magnetic field that allows a magnet to levitate above the superconductor -- showing the Meissner effect.

“Some samples exhibited drastic changes in its resistivity at 100 degrees Celsius, however, we believe the phase transition was caused by impurities (in the samples),” the committee said. “Like the research conducted in other countries, there was no phase transition in samples with less impurities.”

It added that the Seoul-based startup Quantum Energy Research Centre, headed by Lee Suk-bae, the first author of the LK-99 research, did not send the superconductor samples for cross-validation as promised.

The committee, composed of eight research teams from local universities including Seoul National University, Postech and Hanyang University, has conducted monthslong validity tests on the so-called superconductor, since its launch in August.

Experts say even if Quantum Energy Research Centre decides to send its LK-99 samples to the committee, it is "highly unlikely" it would prove the validity of a superconductor.

“Unlike the research center’s claim that single crystal samples with little impurities show a drastic drop in resistivity, many papers, (before the committee’s announcement,) have reported that impurities in the re-created samples -- in particular, copper sulfide -- were responsible for it,” said Kim Sung-soo, a senior researcher at the carbon composite materials research center at the Korea Institute of Science and Technology.

Kim noted the samples from the lab might consist of structures that they cannot understand or characterize, or even contain impurities, therefore hardly supports their claim that LK-99 is a superconductor.

But Kwon Young-wan, who claims he led the superconductor research as opposed to first author Lee’s claims, held a press conference on Monday, and said, “I still believe LK-99 is a superconductor.”

Kwon added that the committee has failed to re-create the room-temperature superconductor because it is impossible to prove the validity of the research within several months.

Commenting on one of the research team's YouTube videos showing the LK-99 levitating in a tilted position, Kwon said, “It exhibits a lower level of the Meissner effect than high-temperature superconductors.” But he declined to disclose the video on re-creating the superconductor, saying it is not ready yet.

On July 22, two research papers separately uploaded by Lee and Kwon on the open-access preprint repository arXiv created buzz worldwide that Korea has created one of the holy grails in science -- a room-temperature superconductor.

If realized, the material capable of carrying electrical charges with no energy loss along the way could have revolutionized the energy efficiency of power grids, electronic devices and transportation.

By Byun Hye-jin (hyejin2@heraldcorp.com)