Everyone in this thread needs to understand that particularly for materials science, and particularly when there is bad methodology documentation, it is really, really normal for early replication attempts to fail. What works in one lab will often need to be adjusted to work in another, with different equipment, altitude, humidity, all sorts of stuff. Making it even worse, apparently the original team can't even get production correct in more than 10% of runs! Combined with the slipshod methodology, doesn't this make you feel like it was silly to release the arXiv paper when they did? Well, the LK-99 team agree, according to them it was a rogue industrial scientist that they'd apparently fired four months ago who published it to arXiv with himself listed as third author. They wanted more time to nail down sample production and otherwise make a paper to their standards before release, but it effectively leaked and to avoid having credit taken from them for potentially months (or like, forever - science can be brutal) some of them decided to publish what they had on hand within a few hours. This sucks for them, a lot. I don't believe that their intention was to put out work with errors in it or incomplete methodology.<p>Secondly, this all happened two days ago! If the methodology was perfect, I still wouldn't expect good replication results back within two (part non-business!) days.<p>I don't know if this material is legit. I really hope it is. But the process of figuring that out could potentially take months (or more), and a two-day-later failed to replicate is not a death sentence.<p>As much as it sucks, this is really just going to take time to prove it's not a superconductor. If it is a superconductor, we may not know for a while either, unless one of the influencers/"makers" attempting to reproduce the material succeeds and posts some good convincing video of flux pinning or other Meissner effect stuff (that person is going to go insanely viral, if it happens).
What they have produced is clearly not LK-99.<p>They write that:
"
As shown in Figure 9, the x-ray diffraction spectrum of the
ground powder of the finally sintered product is highly consistent with the x-ray diffraction
spectrum reported by Lee et al.[3] and coincides well with the diffraction pattern of the apatite.
This proves that we have successfully synthesized the modified lead-apatite as Lee et al.[3.4]
"<p>(First off, you need to pay to the spectrum swear jar. an XRD pattern is a <i>pattern</i>, not a <i>spectrum</i>, it resolves space, not energy.)<p>But looking at figure 9 shows that the material is not the same.
They are missing a peak at ~17.5 degrees, and have an extra one around 25 degrees.<p>Further, all the peaks seem to be shifted about the same amount from the LK-99 structure, as the LK-99 is from pure lead-apatite.
This indicates that they have an even smaller unit cell. So if the .5% compression in the original LK-99 paper is correct, there could easily be an overcompression present in this article.<p>All the XRD pattern tells you is that they produced something wrong, an that it did not superconduct.<p>It makes it impressive how pure the phase was in the original LK-99 paper.<p>I will however say that there are some problems with the XRD pattern in the original paper too:
They did not write which energy the XRD was measured at, one would then guess that it is Cu-Ka, but who knows.
Under any circumstances, a peak should not be missing completely from a powder measurement (if it was a pellet, it could be missing due to orientation effects)
For the non-chemists/physicists:<p>Recently[1], there was an exciting claim that a new type of material could conduct electricity perfectly at room temperature (this is what is meant by "superconductivity")[4]. This material was a version of lead-apatite [2], a type of mineral, that was altered with certain additions and made by combining two other materials, lanarkite and copper phosphide.<p>The researchers writing this report wanted to check if this claim was true. So, they made the same types of materials (lanarkite, copper phosphide, and the altered lead-apatite) and tested how they conducted electricity and reacted to magnets.<p>What they found was that lanarkite (Pb2SO5) didn't conduct electricity well at all, and copper phosphide Cu3P) conducted electricity similar to a semiconductor [3]. The altered lead-apatite, which was supposed to be the superconductor, behaved more like a semiconductor (a type of material that can sometimes conduct electricity, depending on conditions).<p>Also, a key property of superconductors is that they repel magnets. But when the researchers put a magnet near their lead-apatite, there was no repulsion.<p>Because of these tests, they're suggesting that the original claim about this room-temperature superconductor should be re-examined more carefully. It doesn't seem to behave like a superconductor in their tests.<p>[1] <a href="https://news.ycombinator.com/item?id=36864624">https://news.ycombinator.com/item?id=36864624</a><p>[2] <a href="https://en.wikipedia.org/wiki/Apatite" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Apatite</a><p>[3] <a href="https://en.wikipedia.org/wiki/Semiconductor" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Semiconductor</a><p>[4] <a href="https://en.wikipedia.org/wiki/Superconductivity" rel="nofollow noreferrer">https://en.wikipedia.org/wiki/Superconductivity</a>
I think this theoretical result by Griffin at the Livermore Lab explains why labs are having difficulty replicating the LK-99 sample: <a href="https://arxiv.org/pdf/2307.16892.pdf" rel="nofollow noreferrer">https://arxiv.org/pdf/2307.16892.pdf</a><p>There are basically two repeating crystal cells. Her theoretical calculation shows superconducting properties when you substitute one cell for copper, but not the other. The "bad" substitution is a lower energy substitution that occurs more easily.<p>"Finally, the calculations presented here suggest that
Cu substitution on the appropriate (Pb(1)) site displays
many key characteristics for high-TC superconductivity,
namely a particularly flat isolated d-manifold, and the
potential presence of fluctuating magnetism, charge and
phonons. However, substitution on the other Pb(2) does
not appear to have such sought-after properties, despite
being the lower-energy substitution site. This result hints
to the synthesis challenge in obtaining Cu substituted on
the appropriate site for obtaining a bulk superconducting
sample."
Research out of Berkeley, 1 Aug 2023: theoretical analysis suggests high-Tc superconductors from apatite possible, points to synthesis challenges.<p>> Finally, the calculations presented here suggest that
Cu substitution on the appropriate (Pb(1)) site displays
many key characteristics for high-TC superconductivity,
namely a particularly flat isolated d-manifold, and the
potential presence of fluctuating magnetism, charge and
phonons. However, substitution on the other Pb(2) does
not appear to have such sought-after properties, despite
being the lower-energy substitution site. This result hints
to the synthesis challenge in obtaining Cu substituted on
the appropriate site for obtaining a bulk superconducting
sample.<p><a href="https://arxiv.org/abs/2307.16892" rel="nofollow noreferrer">https://arxiv.org/abs/2307.16892</a><p>Edit: Layperson summary from <a href="https://twitter.com/Andercot/status/1686215574177841152" rel="nofollow noreferrer">https://twitter.com/Andercot/status/1686215574177841152</a>. It's crazy for the sim to not only be favorable towards SC, but also showing results that align with what the researchers proposed and what the replicators are experiencing (difficulty in synthesis).<p>> The simulations modeled what the original Korean authors proposed was happening to their material - where copper atoms were percolating into a crystal structure and replacing lead atoms, causing the crystal to strain slightly and contract by 0.5%. This unique structure was proposed to allow this amazing property.<p>> Lastly, these interesting conduction pathways only form when the copper atom percolates into the less likely location in the crystal lattice, or the 'higher energy' binding site. This means the material would be difficult to synthesize since only a small fraction of crystal gets its copper in just the right location.
> In addition, when a pressed Pb10-xCux(PO4)6O pellet is located on top of a commercial Nd2Fe14B magnet at room temperature, no repulsion could be felt and no magnetic levitation was observed either.<p>So what about the video[1] that shows magnetic levitation occurring?<p>Since the linked article was unable to reproduce this effect, it seems there are two possibilities:<p>1. The video is fake (which is really, really hard to imagine since that would predictably end the authors' careers).<p>2. The sample synthesized for the linked article doesn't match the original one for whatever reason.<p>[1] <a href="https://sciencecast.org/casts/suc384jly50n" rel="nofollow noreferrer">https://sciencecast.org/casts/suc384jly50n</a>
Doesn't it seem like there should be some sort of annealing process required? this material being essentially a powder smashed into a tablet form seems like it would likely be a very poor conductor unless the superconducting properties not only existed in each of the granules of the powder, but also can easily transition between each of the boundaries. So wouldn't you want the final thing to be closer to like a ceramic form? (probably not understanding something here)
Seems there is new support that its legit!<p><a href="https://twitter.com/Andercot/status/1686215574177841152" rel="nofollow noreferrer">https://twitter.com/Andercot/status/1686215574177841152</a><p>National Lab (LBNL) results support LK-99 as a room-temperature ambient-pressure superconductor.<p>Simulations published 1 hour ago on arxiv support LK-99 as the holy grail of modern material science and applied physics.<p><a href="https://arxiv.org/abs/2307.16892" rel="nofollow noreferrer">https://arxiv.org/abs/2307.16892</a>
Given the stark contrast in behavior between their sample and the one described in Lee et al., is this even the same material? Surely while the conductive characteristics can be explained by errors in measurement procedure, why would the behavior in a magnetic field be different? Were the original authors being dishonest? Was the replicated material different? The X-ray analysis seems to support that they are very similar, if not the same. I expect we're going to see more of this over the next week as more Chinese labs manufacture the samples.
> In addition, when a pressed Pb10-xCux(PO4)6O pellet is located on top of a commercial Nd2Fe14B magnet at room temperature, no repulsion could be felt and no magnetic levitation was observed either.<p>Unless we assume the original paper's authors were straight up lying, it sounds like this paper's author didn't end up with exactly the same material?
The biggest question in this whole thing was, why not bring a sample to another lab for verification? Well, now we’re starting to get some reproduction attempt results anyways.
Maybe not yet the final nail in the coffin but I would no longer bet much on a successful replication. Which leaves me wondering how we got the initial papers. Does fraud make any sense, how could you possibly benefit from something like this? And if I would think that I might have produced a room temperature superconductor due to experimental errors, I would double and tripple check what I did. Assuming there is time for that. So incompetence? Self-delusion due to a desire for it to be true?
I get a strong feeling that this guy is like the lab that said they found life that didn’t use phosphorous for dna a few years back. I think it just turned out to be shoddy lab work and not accounting for contaminants in their lab chemicals.<p><a href="https://www.nature.com/articles/nature.2012.9861" rel="nofollow noreferrer">https://www.nature.com/articles/nature.2012.9861</a><p>If you find something extremely rare that rewrites what we know you need to be damn sure that what you are saying is true. But some people rush to the media and trying to publish it before they’ve even made sure.
A little bit of a rabbit trail, but with this and similar science/reporting issues, I find myself wishing both the hype and the vitriol was taken out completely. What if the world could follow the LK-99 team and replication attempts in near real time and everyone had a sense like "if this succeeds, great, if not, we know one more way it doesn't work". And what if the millions of various studies on any topic were publicly accessible, instantly searchable, discussed intelligently, then novel ideas bubbled up and became studies themselves.<p>I understand I'm being naive here and ignoring "little" things like funding, profit motives, and basic human nature. But more what I'm suggesting is that there has to be a way to speed up scientific research and application while toning down the hyperbole. This really became apparent to me during Covid. There _have_ to be ways to rethink from first principles how we do and report on science.
A paper dropped on the 29th examining if their theory of LK99's superconducting mechanism was plausible. The good news that it is. The bad news is that the copper atoms need to end up in the least likely place in the crystal.<p>Long story short, though the ingredients are easy to find we should expect reproduction to take longer than we first thought.
Can anyone ELI5 - Is the compound/material used for LK-99 that unique? Are there other, similar materials that might also have this 'quantum well' quality?
I’m surprised/impressed by the quick turnaround between the original LK99 paper submitted on 22 Jul 2023 and this reproduction attempt submitted on 31 Jul 2023. Could there have been a pre-print of the original paper that allowed the reproduction attempt to begin earlier?
How many days have scientists been working on this? Like 2, not including the weekend? I'm impressed that results and papers are already starting to come out.
This is another example of why to do great science you need to do great engineering. The original group rushed to publish the paper without polishing the details, and now other groups are struggling to replicate their results.
I was just thinking that it would be funny if, having actually discovered a high-temp ambient pressure superconductor, rather than announce it, go around to other labs and replace their samples with yours.
Let's hope it can be settled fast. The worse thing that can happen to a revolutionary claim like this is for it to become a "cold fusion" type of subject, with lots of "confirmations" and many more non-replications.