The experts think that the LK-99 is a superconductor
Unidentified Superconducting Objects: The First Year at a University of Science and Technology, Is LK-99 Still Getting Closer
LK-99’s purported superconductivity drew immediate scrutiny from scientists. Inna says her first thought was no. “These ‘Unidentified Superconducting Objects’, as they’re sometimes called, reliably show up on the arXiv. There’s a new one every year or so.” The recent discoveries of superconductivity could potentially have an impact on some technologies such as computer chips and maglev trains. Historically, progress in superconductivity has had tremendous benefits for basic science, but little in the way of everyday applications. There’s no guarantee that a material with a room-temperature superconductor would work out in the real world.
We could still potentially see some of the things that a room-temperature superconductor is supposed to usher in, even if it’s never discovered. Consider electricity grids and more powerful medical devices. Those developments might depend on more incremental improvements to make existing superconducting materials cheaper to manufacture and easier to deploy.
Experts tell The Verge it’s still too soon to make a final call on LK-99. Nevertheless, some early results have captured people’s imaginations on social media. A piece of LK-99, made by a research team from the University of Science and Technology, is appearing tolevitate on the internet. A material that expels a magnetic field is a sign of diamagnetism. It’s a classic signature of a superconductor, through a phenomenon called the Meissner effect, and the authors who first wrote about LK-99 also included a video of it partially levitating.
If it can’t be manufactured, it is a laboratory curiosity that will win a Pulitzer Prize, but it is still curious. It’s a really long way from a material which everybody can get excited about as a physics experiment to something which an engineer will say, ‘Yes, I’m going to buy that and put it in my machine,’” Grovenor says.
Other big-name institutions have yet to share their results, including researchers at Argonne National Laboratory and FAMU-FSU College of Engineering. “Within a week or two, we’re going to have 20, 30, 40, 50, or 100 labs that will have done various syntheses. So it’s going to be clear pretty quickly,” says Larbalestier.
That is not good for the field. And it makes most of us very, very wary of claims and cases where people can’t reproduce their data.” Mason says. “Science works by reproduction and by our ability to be open with each other and test each other’s results.”
The Rochester Superconductor, Redd Matter, and the Zero Resistance Test of Leptium: After Two Months, The Verge Revisited
The Rochester researchers tried again. In March, they published another paper on a room-temperature superconductor made from nitrogen, hydrogen, and the rare earth metal lutetium. The word “reddmatter” comes from a fictional piece of Star Trek that creates black holes. That paper is still under scrutiny, especially since one of the key researchers from Rochester faces separate allegations of plagiarism and data fabrication in his other work.
David Larbalestier, chief materials scientist at the National High Magnetic Field Laboratory and a professor at the Florida A&M College of Engineering, says that the discovery is out of the blue. “I have no idea what the idea, frankly, behind doping this [mineral] with copper was.”
The Korean team’s sample was consistent with the data produced by the Southeastern University team. Several researchers are questioning the claim of achieving zero resistance. C. Evan Zalys-Geller of the Massachusetts Institute of Technology in Cambridge says that it isn’t possible to tell between a zero resistance superconductor and a low-resistance metal. Members of the team did not respond to the request for comment.
A heat anomaly test that is standard for major laboratories studying these kind of materials was not performed by the researchers. “All superconductors that have ever been proven to be superconductors show this specific heat anomaly,” he says. “If there is no specific heat anomaly, it ain’t a superconductor.”
To start, there were inconsistencies in the data; the two preprints disagree with each other. There’s reportedly also conflict between the authors (there are three authors named on one paper and six on the other). An author of the other paper said that the preprint with fewer authors had many defects. The author said that the preprint was uploaded to arXiv without his permission. Kim and other corresponding authors of the papers didn’t respond after being contacted by The Verge.
That makes the efforts we’re seeing now to try to duplicate the findings in those preprints crucial. That issue is one of many that gives experts pause. They raised a range of concerns in interviews with The Verge.
Online Sensation: Claimed Superconductivity of LK-99 on Forks, Folded Graphene, and Atomically Thin Carbon
Uncertainty surrounding the structure of LK-99 makes it hard for researchers to draw conclusions from theoretical studies.
Frustrated by the atmosphere of hype, some scientists have taken to mimicking the levitation videos with everyday materials suspended by string and other props. “I opened Twitter up one day and noticed a bunch of sketchy videos with little floating pebbles,” says Eric Aspling, a physicist at Binghamton University in New York. In response, he uploaded a video featuring a “sample of LK-99 shaped as a fork” suspended by tape. He thought, how can anyone be convinced by this?
Speculation continues despite the limited success of the replication attempts. Unverified videos of samples, supposedly levitating because of superconductivity, have circulated as viral evidence, despite the fact that many materials — including graphene, frogs and pliers — can exhibit similar magnetic behaviour.
Even if future experiments confirm flat bands, the feature does not mean the material would display room-temperature superconductivity, Schoop says. Flat bands are shown to have superconductivity at -271 C ( 1.7 K), and they are associated with other materials, such as ‘twisted’ layers of Graphene and atomically thin carbon. This does not give evidence of superconductivity in the lead based LK-99, according to Schoop.
Source: Claimed superconductor LK-99 is an online sensation — but replication efforts fall short
The Flat Bands of Lead Phosphide: Evidence from a Newly Discovered Superconducting Metal LK-99
Griffin agrees that knowing the structure is essential. But she says that the structure found by the Korean team is similar to that of other lead phosphate minerals. “So it’s not too bizarre to think it possible.”
A solid state chemist at a university in New Jersey says that all theory papers have the same assumption about the structure, but they differ in theirsuggestions of flat bands. She says that she doesn’t believe in any of the DFT until she knows the correct crystal structure.
On July 31, a theoretical analysis was posted on the micro-blogging website. Sinéad Griffin, who studies quantum materials at Lawrence Berkeley National Laboratory in California, shared her theory paper, accompanied by a gif of former US president Barack Obama performing a ‘mic drop’. The optimism was spurred by the discovery that LK-99 has flat bands, a feature that shows electrons are correlated with each other. TheFlat band systems show interesting physics. “So when a material is predicted to have a flat band, people get kind of excited.”
The materials of both teams are different, according to Robert Palgrave, a chemist at University College London. Both X-ray diffraction patterns are significantly different from the Korean team’s patterns and from each other, says Palgrave. Nature requested comment from the members of the group, but they did not reply.
Physicist Veerpal Singh Awana acknowledged that there were small differences between the sample from the National Physical Laboratory and the one from the Korean team. “Our LK-99 is very similar to that as the reported superconducting LK-99,” he says.
To confirm that material’s structure and identity, replicators used X-ray diffraction, an atomic imaging technique. The Beihang team concluded that their sample’s structure was “highly consistent” with that of LK-99.
A research team has discovered a new type of superconductor made from lead, which appears to have a ‘flat band’. The team used a method called’Meissner effect’ to find the structure of the new material. The material is similar to other lead phosphates and it may be the first time a superconductor has been discovered with a ‘flat band’.