The scientific community is still scrambling to confirm the recent revolutionary claim by Korean scientists that they have created a room-temperature, ambient-pressure superconductor. But with enough brainpower looking into the subject of the LK-99 material, it's bound to be a matter of time before the superconductivity claims are fully confirmed or denied.
Once again, researchers in China seem to be at the forefront: today, scientists with the Physics Department of Southeast University, a top university in Nanjing, China, have reported measuring zero electrical resistance, a key requirement for superconductivity, in a sample of LK-99 they produced from scratch. However, that comes with the caveat that they could only achieve the properties at -163C, not at the room temperature touted by the original paper. As with other efforts from other teams, two of which claim to have confirmed certain other aspects of the claimed superconducting breakthrough, the new results from the Southeast University team are preliminary — the team is still studying different methods of fabricating the material, with plans to provide more results in the future. Other research teams are also still working to replicate the initial claims.
After having successfully synthesized LK-99, which they say was purer than the samples the original Korean time achieved, the Chinese research team helmed by Doctor Sun Yue looked into the material's conductive properties, finding some "very interesting electronic properties of this material." As a reminder, LK-99 is a compound of lanarkite [Pb₂SO₅] and copper phosphide [Cu₃P] baked within a 4-day, multi-step, small batch, solid-state synthesis process that was nevertheless also achieved over a Russian kitchen counter.
In this case, the "very interesting electronic properties" refer to the material's ability to conduct electricity without any resistance — leading to incredible efficiency savings that could get PC enthusiasts something like that 30 GHz processor Intel promised but never delivered.
The above video shows the researcher explaining the findings. Using a four-point probe method, the scientists measured their synthesized LK-99 at 0 resistance at an ambient temperature of 110K (-163 º C) and at normal air pressure. They also verified that LK-99 transitioned in and out of its zero resistance state depending on whether it was subject to a strong electric field, another hallmark of superconductivity. Here's a summation of the team's findings, taken from the Wikipedia live-tracker page:
"Claimed to have synthesized LK-99 and to have measured superconductivity up to a temperature of 110 kelvin. Claimed to have observed an abrupt drop in resistance between ~300K and 220K, aligning with the Korean LKK team's results. Claimed to have confirmed structural consistency with x-ray diffraction."
The confirmed absence of electrical resistance now comes together with yesterday's news that confirmed at least one-half of the superconducting equation was solved: LK-99 showcased the Meissner effect (originally Meissner-Ochsenfeld), which results in the levitation of materials as they interact with the Meissner-effect-induced magnetic field. And now, it seems the other half of the equation, resistance-less electrical conduction, was verified in LK-99.
But questions remain even here: it seems that LK-99 only shows superconductivity at 110 kelvin (-163C), which disputes the "room-temperature" bit originally claimed (although all tech enthusiasts that have dabbled in liquid nitrogen cooling know that 110 kelvin is handleable, if not practical). It's also unclear why LK-99 would show both diamagnetism (responsible for levitation) and superconductivity, but within different temperature bands — expectations would paint it more as a "buy one, get two" promotion.
Yet one plus one generally being equal to two, we seem to have independent confirmation of several facets of a superconducting compound being successfully synthesized.
But while this is incredibly promising news, there are still caveats. For one: it's strange that two teams verified different halves of the superconducting requirements, but no team has successfully verified both (as of the time of writing). You would think that it would make more sense for one side to take more time to crack than the other; otherwise, why didn't the initial Meissner-effect observation also show the hallmarks of zero electrical resistance? What is stopping these teams of extremely talented individuals from achieving what others before them did in full?
In the video, Professor Yue himself says that while promising, the team's results aren't proof that LK-99 is the superconductor breakthrough we've been waiting for. For that to happen, you'd have to wait for a credible institution to confirm both the Meissner effect and the zero electrical resistance halves of the equation — at the same time. And even then, it won't be enough: their announcement (cue all other scientific prizes) will have to be followed up by other institutions up to a point where there's enough overlap in the results that says: "This is more than fabricated data or a mere fluke".
And that's not saying anything of all the sweet spots this material needs to hit to be the hero we want it to be. It has to be abundant enough and easy enough to access that it's relatively cheap to mine; then it has to be relatively cheap to process and synthesize at a mass scale; and then it still has to be turned into actually useable bits of electronics that are compatible enough with our current fabrication methods. Talk about high standards; that's years of work right there.
For now, LK-99 seems to have some limitations. It's currently hard to synthesize at high purities (because it only happens in very specific areas of the compound), meaning yield is likely to be poor. And in fact, perhaps this purity problem (acknowledged in the original paper) is the root of most of these issues: scientists have had a difficult time creating enough quantities of the material that display any of the superconducting or diamagnetic features. There could be unknown factors at play at a chemistry level that explain the low yield, but if that's true, then we can't really trust the replicability of the results just yet.
Another limitation is that the material could be one-dimensional - meaning that it only presents superconductivity on a section of it, which could be why the levitation in the original video wasn't even. That still means a load of possible applications while unlocking new ones — it's never a pure loss.
For now, the jury is still out on the original Korean teams' claims of a room-temperature superconductor, and the Southeast University researchers will continue to study the new material and fabrication methods as they search to find the correct mixture to replicate the room-temperature superconductor. For now, some claims have been preliminarily confirmed, while others remain out of reach. Several other teams are also racing to validate the paper, so we're sure to learn more over the coming days.
