Room temperature superconductor paper published

[DaveC426913]

Sounds like preliminary replication are starting to trickle in.

https://www.tomshardware.com/news/superconductor-breakthrough-replicated-twiceNot a reputable source, but I'm gonna stay tuned

 

[Haborix]

Sounds like preliminary replication are starting to trickle in.

https://www.tomshardware.com/news/superconductor-breakthrough-replicated-twiceNot a reputable source, but I'm gonna stay tuned

Important to note, the simulation results say nothing about the ambient pressure part of the claim (other than to quote it). And the other replication mentioned in that article is the replication of the manufacturing process. Taking all of these as true, we still wouldn't have replication of the most interesting part of the claim: a high Tc superconductor at ambient pressure.

 

[berkeman]

Sounds like preliminary replication are starting to trickle in.

https://www.tomshardware.com/news/superconductor-breakthrough-replicated-twiceNot a reputable source, but I'm gonna stay tuned

Tom's Hardware is not a reputable source? How dare you!

 

[Vanadium 50]

citing this paper as replication

I do not consider a calculation, no matter how good, as experimental replication.

 

[mfb]

Wikipedia has a table

Group by group as of now:

* Diamagnetism seen, waiting for resistance measurements
* No diamagnetism, high resistance
* Big changes in resistance as function of temperature, but low or no resistance only at 110 K. No Meissner effect.
* No diamagnetism seen
* Resistance doesn't drop to zero in measured temperature range
* No diamagnetism seen
* No clear results yet

Just one group seeing diamagnetism is a bad start. Superconductivity implies (ideal) diamagnetism but the reverse is not true - even if the material is strongly diamagnetic it doesn't have to be a superconductor.

 

[romsofia]

A fun article by nature:

https://www.nature.com/articles/d41586-023-02481-0

 

[fluidistic]

Another thibg to have ib mind is that even if we find a RT SC at 1 atm, it doesn't necessailty make it useful. Not only because of the ability to make wires but also due to I max. It is said that if such a cuprate was found, it would be of little use, due to low I max. It may not lead to any technological revolution. Not sure this would be worth a nobel prize.

 

[Baluncore]

It is said that if such a cuprate was found, it would be of little use, due to low I max.

That may be true for electrical and transport applications, but it could well be a benefit to information processing or instrumentation.

 

[Vanadium 50]

Except in the dictionary, confirmation comes before application.

 

[Baluncore]

Except in the dictionary, confirmation comes before application.

I can make it consistent, by reverse sorting the dictionary, which would help to get an earlier retraction.

 

[Vanadium 50]

Here's another thing that bugs me "LK"? Really? They named it after themselves? Not only is it worth 20 points on the Baez Index, do they not remember the GFAJ-1 fiasco?

 

[Baluncore]

Fiasco normally comes before redaction and retraction.

 

[Vanadium 50]

I don't think the arsenic crowd ever retracted. However, I think it has been generally accepted as wrong. "Too good to check" is a common problem with such papers.

 

[mfb]

Here's another thing that bugs me "LK"? Really? They named it after themselves? Not only is it worth 20 points on the Baez Index, do they not remember the GFAJ-1 fiasco?

Worked (possibly) for J/Psi.
As far as I understand they picked that name as students and at a time they didn't expect that material to get larger attention.

 

[Swamp Thing]

This didn't happen with the last time we had the first room temperature superconductor, the Indian gold-silver amalgam. Or maybe it was the time before that.

Does this pass the smell test? It's pretty stinky. Doesn't make it wrong, but...

1. The paper, as stated, is not very good. Doesn't make it wrong, but...
2. The evidence plots are, at least to me, not so clear. Doesn't make it wrong, but...
3. The authors' publication history is not in experimental superconductivity - it appears to be more in theory, and non-SC theory dominates. Doesn't make it wrong, but...
4. The research was apparently conducted at a commercial company, This appears to be the very first paper out of this company, at least in English. Doesn't make it wrong, but...
5. The idea of increasing the internal pressure by substitution is not new. It has had some success in the past, but nothing like this. Doesn't make it wrong, but...
6. The authors claim to have a new family of materials. The first and thus far only member of this family has the property of interest. Doesn't make it wrong, but...

You may be sensing a theme.

Smells like... uh, ... "but" ?

 

[BWV]

Is it dead or does it still just smell funny?

We successfully synthesized polycrystalline LK-99-like ceramic samples with a solid-state-sintering method. Powder X-ray diffraction shows that the main contents are Pb10−xCux(PO4)6O and Cu2S, consistent with recent reports [arXiv:2307.12037; arXiv:2308.01192]. In some small flaky fragments, we successfully observed ``half levitation'' atop a Nd2Fe14B magnet. Using magnetization measurements on such small pieces, as well as on a large piece which does not exhibit the half levitation, we show that the samples ubiquitously contain weak yet definitive soft ferromagnetic components. We argue that, together with the pronounced shape anisotropy of the small fragments, the soft ferromagnetism is sufficient to explain the observed half levitation in strong vertical magnetic fields. Our measurements do not indicate the presence of the Meissner effect, nor zero resistance, in our samples, leading us to believe that our samples do not exhibit superconductivity.

https://arxiv.org/abs/2308.03110

 

[mfb]

https://en.wikipedia.org/wiki/LK-99#Replication_attempts

Some groups see some diamagnetism, but no one sees superconductivity.

 

[Vanadium 50]

Is there any result that cannot be explained by this material being a diamagnetic metal?

 

[mfb]

Nature: LK-99 isn’t a superconductor — how science sleuths solved the mystery

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.

Multiple groups reproduced the claimed "levitation" with ferromagnetic elements and the sudden resistance drop seems to come from copper sulfide undergoing a phase transition.

 

[George Jones]

University of Nottingham physicist Philip Moriarty doesn't hold back about the way this initially unfolded

 

[Vanadium 50]

Well, it sounds like we can stick a fork in it. At least until next time.

 

[Haborix]

Well, it sounds like we can stick a fork in it. At least until next time.

But if it sticks to the fork doesn't that mean it is a superconductor?

 

[DrDu]

As a fun fact, I want to mention that this material is a close relative of the common mineral pyromorphite: https://en.wikipedia.org/wiki/Pyromorphite

 

[mfb]

Co-Authors Seek to Retract Paper Claiming Superconductor Breakthrough
(without paywall)

This is the Dias paper not LK-99, but it still feels relevant.

 

[Vanadium 50]

A lot of the Dias work is...um...troubled.