Hopes are dashed when it is confirmed that LK-99 is not a room temperature superconductor
The dream seems to be over. After several intense weeks of speculation and drama, more and more labs have managed to recreate LK-99, also known as Modified Lead Apatite. The material was believed to be the first superconductor at room temperature and pressure, a claim that met with healthy skepticism and enthusiasm. Extraordinary claims require extraordinary evidence.
The LK-99 saga began in late July when a team led by Sukbae Lee and Ji-Hoon Kim at Quantum Energy Research Center, a Seoul-based startup, released preliminary papers claiming that the LK-99 is normally a superconductor at pressure and at temperatures up to at least 127 °C. All superconductors confirmed so far only work at extreme temperatures and pressures.
Unfortunately, the tests did not come about. The labs reproduced the material following the original article’s instructions and found no evidence of superconductivity in the newly uploaded documents. Actually quite the opposite.
Superconductivity begins at a critical temperature below which the material can transmit electricity without resistance. According to some new data, LK-99’s resistivity increases with decreasing temperature, similar to that of an anti-superconductor.
A key preprint from tonight comes from ICQM, a top research center in China (whose faculty includes several CMTC alumni). No SC but a small amount of ferromagnetism (no diamagnetism) was found in minute flakes of LK99 samples. No SC at all in all 3 reports
— Center for Condensed Matter Theory (@confided_the) August 8, 2023
In the case of a superconductor, the aim is for the resistance to become zero above a certain temperature. At the temperature where superconductivity starts, you should see a very clear change in resistance.
Other expected measurements were a drastic change in heat capacity at the critical temperature and the change from nonmagnetic to diamagnetic. Diamagnetism has been seen in several videos (although one article claims it’s ferromagnetism), but it’s not that interesting on its own. Many materials are diamagnetic without many revolutionary applications.
Although the development is certainly disappointing, materials science continues to make advances in superconductivity. New materials with revolutionary properties are expected to appear in the next decade. They still need cooling, but using liquid nitrogen as a coolant isn’t too expensive since it’s the most abundant gas in the atmosphere.
Scientists don’t know much about how superconductivity occurs in a material, so finding a material that is superconductive at room temperature and pressure is difficult. The work goes on.