A team of researchers has made a bold claim that they have created materials that can conduct electricity perfectly at room temperature and ambient pressure. However, many physicists remain highly skeptical of this claim. Hyun-Tak Kim, from the College of William & Mary in Virginia, speaking to media, states that he is willing to support anyone attempting to replicate his team’s work.
Superconductors are materials that allow electricity to flow without any resistance, which could greatly reduce energy costs in electronics. However, until now, researchers have only been able to achieve superconductivity under extreme conditions, such as very low temperatures and high pressures.
Kim and his colleagues claim to have created a material, called LK-99, that is superconductive at room temperature and pressure. If this claim withstands scientific scrutiny, it would be an extraordinary accomplishment. However, given previous reports of breakthroughs in superconductivity that were later retracted and the inability of other teams to replicate the results, there is a need for rigorous evidence.
To create LK-99, Kim and his colleagues mixed various powdered compounds containing lead, oxygen, Sulphur, and phosphorus. They then heated these powders at a high temperature for several hours, causing them to chemically react and transform into a dark grey solid.
The researchers measured the resistance of a millimeter-sized sample of LK-99 at different temperatures. They found that the resistivity decreased sharply from a significant positive value at 105°C (221°F) to nearly zero at 30°C (86°F).
In addition, the researchers tested the material’s response to a magnetic field at various temperatures. They observed the Meissner effect, a phenomenon where superconductors expel magnetic fields. To demonstrate this effect, they placed a piece of LK-99 above a magnet, and it levitated above the magnet’s surface.
However, only one edge of the material fully levitated, while the other remained in contact with the magnet. Kim attributes this imperfection to the sample, suggesting that only a portion of it becomes superconductive and exhibits the Meissner effect.
Currently, two papers discussing LK-99 are available on the preprint service arXiv, which does not conduct peer review. Another related study was published in the Journal of the Korean Crystal Growth and Crystal Technology in April. Kim is a co-author of one arXiv paper, while the other is authored by his colleagues from the Quantum Energy Research Centre in South Korea, some of whom filed a patent application for LK-99 in August 2022.
Although both papers present similar measurements, Kim claims that the second paper contains “many defects” and was uploaded to arXiv without his permission. In that paper, the work is described as ushering in a “new era for humankind.”
While some social media commentators hailed these findings as a groundbreaking achievement, experts in the field of superconductivity remain largely sceptical. Researchers, such as Susannah Speller and Chris Grovenor from the University of Oxford, argue that there should be clear evidence of superconductivity in multiple measurements, including the response to a magnetic field and heat capacity, which are lacking in the data presented.
Other experts consulted by Science with RV also expressed doubt about the results and the generated data, suggesting that errors in experimental procedures and imperfections in the LK-99 sample could explain some of the findings.
One researcher questioned the theoretical models cited by Kim and his colleagues as explanations for why the new material can exhibit superconductivity under such different conditions than previous materials.
Despite the skepticism, Kim remains confident in his team’s work and encourages other researchers to replicate their findings. Once the research is published in a peer-reviewed journal, which Kim says is underway, he will support those interested in creating and testing LK-99. In the meantime, Kim and his colleagues will continue refining their samples and working towards mass production of this alleged miracle superconductor.
