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Science

LK-99 Isn't a Superconductor - How Science Sleuths Solved the Mystery (nature.com) 94

Researchers seem to have solved the puzzle of LK-99. Scientific detective work has unearthed evidence that the material is not a superconductor, and clarified its actual properties. Nature: The conclusion dashes hopes that LK-99 -- a compound of copper, lead, phosphorus and oxygen -- marked the discovery of the first superconductor that works at room temperature and ambient pressure. Instead, studies have shown that impurities in the material -- in particular, copper sulfide -- were responsible for the sharp drops in electrical resistivity and partial levitation over a magnet, which looked similar to properties exhibited by superconductors. "I think things are pretty decisively settled at this point," says Inna Vishik, a condensed-matter experimentalist at the University of California, Davis.

The LK-99 saga began in late July, when a team led by Sukbae Lee and Ji-Hoon Kim at the Quantum Energy Research Centre, a start-up firm in Seoul, published preprints claiming that LK-99 is a superconductor at normal pressure and temperatures up to at least 127C (400 kelvin). All previously confirmed superconductors function only at extreme temperatures and pressures. The extraordinary claim quickly grabbed the attention of the science-interested public and researchers, some of whom tried to replicate LK-99. Initial attempts did not see signs of room-temperature superconductivity, but were not conclusive. Now, after dozens of replication efforts, many experts are confidently saying that the evidence shows LK-99 is not a room-temperature superconductor. The South Korean team based its claim on two of LK-99's properties: levitation above a magnet and abrupt drops in resistivity. But separate teams in Beijing, at Peking University and the Chinese Academy of Sciences (CAS), found mundane explanations for these phenomena.

Another study, by US and European researchers, combined experimental and theoretical evidence to demonstrate how LK-99's structure made superconductivity infeasible. And other experimenters synthesized and studied pure samples of LK-99, erasing doubts about the material's structure and confirming that it is not a superconductor, but an insulator. The only further confirmation would come from the Korean team sharing their samples, says Michael Fuhrer, a physicist at Monash University in Melbourne, Australia. "The burden's on them to convince everybody else," he says. Perhaps the most striking evidence for LK-99's superconductivity was a video taken by the Korean team that showed a coin-shaped sample of silvery material wobbling over a magnet. The team said the sample was levitating because of the Meissner effect -- a hallmark of superconductivity in which a material expels magnetic fields. Multiple unverified videos of LK-99 levitating subsequently circulated on social media, but none of the researchers who initially tried to replicate the findings observed any levitation.

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LK-99 Isn't a Superconductor - How Science Sleuths Solved the Mystery

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  • by backslashdot ( 95548 ) on Thursday August 17, 2023 @10:37AM (#63774776)

    1. No faster than light travel
    2. No anti-gravity
    3. No ultra-capacity batteries
    4. No room-temp superconductors
    5. No aliens

    • by PPH ( 736903 )
      6. No flying cars
      • by BigFire ( 13822 )

        Flying car isn't hard. Safe flying car that will stand up to insurance requirement is hard.

        • It is hard if not impossible to make one that is quiet, takes off vertically, can fit in a parking spot, and has usable range (double digit miles would be nice).

      • 7. No version of Firefox that doesn't leak memory, or Windows that doesn't crash periodically.
    • Yeah, turns out that the laws of physics are not merely suggestions.
      • In this house we obey the laws of thermodynamics!
      • Why haven't you detected dark matter? Is it like the Aether?

      • FTL is really the only one prohibited in that list (And by extension visiting aliens). Yeah I know alcubiere and all that, but theres too many problems for that to be even plausible for a very long time (Some of the problems might be insurmountable, at least for the FTL version of the alcubiere drive)

        But we dont actually know if ultra charge batteries and room temp superconducters are impossible, we just dont know yet.

    • by wangi ( 16741 )

      no girls

    • No free energy. No free lunch.
    • 6. No reactionless drives

      • by burtosis ( 1124179 ) on Thursday August 17, 2023 @12:25PM (#63775092)

        6. No reactionless drives

        The problem is the moment someone invents one, there is a massive uproar. If only people could be chill, then maybe we could have nice things.

        • The problem is the moment someone invents one, there is a massive uproar.

          That's because they are thinly veiled perpetual motion machines. Often the inventors don't even realise that, but it doesn't make it any less so.

          If only people could be chill, then maybe we could have nice things.

          Sometimes physics doesn't want us to have nice things. No amount of chillness or otherwise will defeat the laws of thermodynamics.

          • Why does heat flow from a colder place to a hotter place inside your car on a sunny day?

            • Eh?

              Heat pumps aren't perpetual motion machines because they don't generate energy from nowhere.

              Unlike the EM dive if it worked.

              • An EM drive would not generate energy from nowhere either.
                How should it do that? It is a just a damn drive ...

                • How should it do that? It is a just a damn drive ...

                  Well, I'm glad you asked!

                  OK, so imagine a drive which produces, say, 1N given a 1kW input without expelling any reaction mass.

                  Now let's say it's attached to a spaceship which is going 10^4 meters per second (10km/s). That's fast, but not impossibly so by any means. Let's also for sake of argument say the ship weighs 10^3 kg, i.e. 1 ton. It's about to be generating 1kW of power, let's have a heavy but not outrageous ship.

                  It's kinetic energy (0.5 *m*v^2) is

                  • Sure.
                    And when did ever anyone claim a reaction less drives uses less energy than you gain when acceleration.
                    Sorry: you are stupid. That is all.
                    But nice try.

                    • And when did ever anyone claim a reaction less drives uses less energy than you gain when acceleration.

                      Anyone with even the most basic grasp of high school physics will claim that.

                      I showed my working. There is no error in my working.

                      If you can't understand it, but still have opinions on physics you can't grasp then you are one of the most raging morons I've encountered.

                    • Sorry: you are stupid.

                      And when did ever anyone claim

                      Also, moron, that's not how physics works. Failing to even realise you are hawking a perpetual motion machine doesn't make it not one. Basic physics shows a reactionless drive can generate free energy. There is not some get-out-of-gaol free card where if you don't say the magical words "it's a free energy machine" then that bit of physics doesn't apply.

                      My god though it shows why the EM drive had such legs and kept going, the internet is full of credulous f

                    • You do not know how physics works.

                      I suggest to get a fucking book about it.

                      The fact that my fancy space ship engine is "reaction less", does not make it a PMM.

                      Dumbass. How should that work? Oh, you can not explain it. Because: it does not work like that.

                      <|[ --- * --- ]<

                      My fancy little space rocket. To make it simple for you: it weights exactly 1kg.
                      In the middle my power core: * a fucking fusion reactor - or solar panel ... up to you.
                      At the right side my fancy new reaction less EM drive. I made it look

                    • F=ma

                      and E=0.5*m*v^2

                      You claim that E is increasing by 1MJ/s. Then the acceleration must be decreasing, which means F must be decreasing.

                      Well, the only way for that to happen is if F decreases with speed, but relative to what? Unless you're about to get a Nobel prize for finding the absolute reference frame of the universe, then your reasoning is flawed.

                      The whole point is it produces thrust for energy in. Supposedly. Except it can't because as I proved (and by the way flinging poo is not actually a counterarg

                    • Sorry,
                      get a physics book.
                      The acceleration is not decreasing.
                      It is always the same ...

                      The whole point is it produces thrust for energy in. Supposedly. Except it can't because as I proved
                      You proved nothing.
                      You are just an idiot who has no clue about the most basic simplest physics.

                      Get some books. Or don't ... up to you.

                    • This is hilarious because now you're denying Newtonian mechanics in the slow speed limit.

                      The acceleration is not decreasing.

                      Great, which means I'm right.

                      I'm going to pick some numbers. You can pick different ones later.

                      m (mass) = 10^3 kg
                      Velocity at t=0 v0= 10^4 m/s
                      Power supply = 1kW
                      Acceleration = 10^-3 m/s/s # Not decreasing which you just said you agreed with, even though this directly contradicts the direct consequences of what you said earlier.

                      Now for the basic, high school physics.

                      k.e. at t=0: e0 = .

          • Wow, three mistakes in one post about physics
            1) a "reactionless drive" has nothing to do with a " perpetual motion machines. "
            2) correct: a " perpetual motion machines. " can not be build based on thermodynamics, but see 3)
            3) thermodynamics has nothing to do with a "reactionless drive"

            Your pick if you made 2 or 3 mistakes, or more.

        • I'm chill, but not liquid nitrogen chill. So, I'm no super conductor, and a moderately good insulator.
        • by syn3rg ( 530741 )
          Very subtle and well played.
          Wish I had mod points to give.
      • by chthon ( 580889 )

        7. No cold fusion...

    • 6. Hot moms in your area are not trying to contact you

    • by jonadab ( 583620 )
      So my perpetual motion machine is in the clear then?

      How about this new medication that cures all diseases?
    • 1 and 2 are very different than 3,4,5 because they require us to be fundamentally wrong about basic physics. It is likely that no room temperature, ambient pressure superconductors can exist, but they don't require us revamping anything to the extent that FTL and antigrav would. This is an important distinction for evaluating how plausible a given claim is.
    • by Ecuador ( 740021 )

      5. No aliens

      Not sure why you say that, there's lots! They didn't let Trump finish his wall!

    • by dohzer ( 867770 )

      5. No aliens

      Sounds like someone hasn't seen the Tic Tac video. I was a doubter too until I saw a blurry white thing on a video, but now I'm sold!

    • Are you an alien?

  • by LSD-OBS ( 183415 ) on Thursday August 17, 2023 @10:38AM (#63774778)

    There was no mystery. Literally the first time I heard about "LK99" was my not-even-a-physicist buddy telling me how he thinks it looks like a diagmagnetic ceramic with pretty good electrical conductivity described by an extremely poorly written paper -- but definitely not a "room temperature" superconductor.

    • And nobody needed to be a credentialed expert to note that the way the 'discovery' was shared looked about 110% like a scam designed to last as long as possible before it fell apart.

      Might be just incompetence, but the fact that it looked like a scam was a more than adequate way to judge it for any practical purpose.

    • I didn’t even read or listen to anything, just went right to the video first and it looked like a regular iron filing. Turns out that’s exactly what it likely was, iron impurities.
  • by kwelch007 ( 197081 ) on Thursday August 17, 2023 @11:13AM (#63774876) Homepage

    I'm not surprised that this didn't turn out to be a room-temp semiconductor. But the third-party research does seem to suggest that doping with copper sulfate significantly reduces resistivity. That might be worth something.

    • Concur. They should look at what's going on with the copper sulfate.
    • > But the third-party research does seem to suggest that doping with copper sulfate significantly reduces resistivity. That might be worth something.

      They actually answer that and say that it's due to a phase transition.

    • Sulfide, not sulfate. The best part of the story so far is copper sulfide specialist Prashant

      Jain "... wait a minute, I know this temperature" noting the similarity to observations reported in 1951. The original Korea paper's florid language "humankind" smelled of momentum of enthusiasm, unethical: probably not, premature and soon embarrassing: yes.

      It might still be worth looking at behavior at interfaces between bulk and impurities, especially if impurities exist in crystalline regions. That was very i

  • by backslashdot ( 95548 ) on Thursday August 17, 2023 @11:32AM (#63774928)

    This is how science works. With religion, the explanation is that you are sinful, didn't pray hard enough, and the heathen pariah group ruined it for everyone.

    • by backslashdot ( 95548 ) on Thursday August 17, 2023 @11:37AM (#63774954)

      If only we had sent in a $50 donation to God's "ministry" the LK-99 would have levitated.

    • This is how science works. With religion, the explanation is that you are sinful, didn't pray hard enough, and the heathen pariah group ruined it for everyone.

      Can you imagine what it would be like if technology required faith to function? My feet and hands are bruised enough as it is getting things to work.

    • Some religions. In others, demons were punishing you or other supernatural beings were playing games with you.
    • Ted, get back to the register. The fedora stand won't run itself.
    • This is how science works. With religion, the explanation is that you are sinful, didn't pray hard enough, and the heathen pariah group ruined it for everyone.

      LK-99 isn't a superconductor because YOU are sinful, didn't pray hard enough, and are a heathen. I mean you personally. You ruined it for everyone with your blaspheming post and were the crack in our collective faith large enough for Satan's power to disrupt God's divine plan for LK-99.

      Heavenly Trump will smite you for your wickedness! I mean, after he smites Jack Smith. And Tanya Chutkan. And Fani Willis. And Alvin Bragg. And, well, a lot others too. But He will get to you real fuckin' soon unless yo

      • Probably, after all he helped me get tickets to the US Open but didn’t do anything to stop civilians dying in wars or kids kidnapped by pedos.

    • What if experimenters buzzkilled the effect with their minds?

  • by dmay34 ( 6770232 ) on Thursday August 17, 2023 @11:32AM (#63774930)

    Some guy on Slashdot 30 years from now:

    "We already have room temperature super conductors and have had them for 30 years. Look at this paper! Bu the gov'ment quashed it!"

  • Heck, within a day of the announcement and accompanying video a youtuber showed how the material was moving in a magnetic field due to nothing more than the Lenz effect. Move copper in a magnetic field, or a magnetic field around copper, and induce eddy currents and reflected magnetism. I was playing around with that effect as a kid, dropping a magnet through a copper tube and telling my friends it was "defying" gravity, LOL.

    • by LSD-OBS ( 183415 )

      Sorry to be "that guy" (I tried to get out of it, but today I am "that guy" according to the roster) -- but Lenz's law has nothing to do with the levitation effect you've no doubt seen in video clips about LK-99. For one thing, Lenz's law requires the conductive object and/or the magnetic field to be moving with respect to each other, in order to induce an opposing force.

      What you see with LK-99 is exactly the same thing as levitating a graphite disc in a magnetic field, and the phenomenon is called diagmagn

      • I'm talking about this video: https://www.youtube.com/watch?... [youtube.com]

        • by LSD-OBS ( 183415 )

          Oh, the clip that Dave plays at about 8:15? Christ I had not even seen that one. That's really ucking embarrassingly awful. Are we SURE this wasn't just some joke that needs a Korean sense of humor to enjoy? Jeezuz.

        • by LSD-OBS ( 183415 )

          Bullshit and lying fakedemics seems to be A Thing in Korea. Like all that business with the human cloning / embryonic stem cells, where Hwang Woo-suk basically just invented fiction for 20 years. Shocking.

  • Letdown (Score:5, Funny)

    by burtosis ( 1124179 ) on Thursday August 17, 2023 @12:36PM (#63775136)
    I haven’t been this disappointed since I ordered some zero ohm resistors.
  • And it when it first came out so many comments online were "The scientific community can't accept a breakthrough by a garage lab!". Don't let your underdog bias blind you to reasonable doubt.

    • And it when it first came out so many comments online were "The scientific community can't accept a breakthrough by a garage lab!". Don't let your underdog bias blind you to reasonable doubt.

      We always get this. Fortunately this one looks to be dying down quite fast, unlike the wretched EM drive. There are still people carrying the torch for that one.

    • And they aren't wrong nor are they invalidated by this result. This is literally how science works. A scientific community can't accept a breakthrough by a garbage lab, so they band together to do actual science to reproduce and validate a claim.
      It's just as healthy to be sceptical as it is to expect major scientific breakthroughs will occur.

    • It just needs to be manufactured over a cold fusion reactor, under a dimly, and dim-wittedly, perceived street lamp. Then it will work for sure!
    • Didn't Newton do experiments in his dorm room?

  • If anyone is interested..
    https://www.youtube.com/watch?... [youtube.com]

  • There is still a levitation video. Does that means they either faked it, or achieved room-temperature supraconducivity by chance, and cannot reproduce the material? Is it possible to levitate without supraconductivity?
  • 1. The earth does not move.
    2. Heavy things fall faster.
    3. What you can't see (germs) can't hurt you.
    4. Continents don't drift.
    5. The universe is contracting.

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