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LK-99: Team of Southeast University observed zero resistance below 110 K

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Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#211

Post by pama »

lambdasquirrel wrote: post #138
jacquesm wrote: post #26

Earlier quoted context omitted.

It's all unusual because it is uncharted territory. My guess would be assuming that it all pans out that this is due to various impurities and that it will take a while before we have a sample that is pure enough that all of these properties can be nailed down for good. What's strange is that drop at higher temps, that's either a measurement anomaly or something really odd.

According to wikipedia, that was observed by the original team in Korea. https://en.wikipedia.org/wiki/LK-99#Replication_attempts > 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-r…

Just a word of caution that Wikipedia entries around LK99 are unusually poor at this point in time. The citation of an attempt to publish it in Nature in 2020 is completely made up when the original Korean only mentions in passing a completely different paper that was withdrawn from Nature at the time. I hope the understandable excitement around this new invention will allow for a correct eventual accounting of the events.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#212

Post by stasmo »

lnenad wrote: post #197
Palpatineli wrote: post #119

Earlier quoted context omitted.

[flagged]

Holy shit what a statement.

The worlds best scientists don’t even know how to make room temp superconductors but this one person on HN is certain that purity doesn’t matter.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#213

Post by overnight5349 »

bilsbie wrote: post #73
psychphysic wrote: post #67

Earlier quoted context omitted.

Could be insulated RTP superconducting crystals, grains, islands with the bulk being a high temperature superconductor?

Yes exactly.

It seems likely. Given that the copper atoms prefer to form a non-superconducting material, it makes sense that there would be regions where the energy is just right to form the correct structure, and you get the incorrect structure everywhere else.

Given the way crystals grow, it then would follow that you'd get discontinuous crystals or grains within the material.

If we're taking bets, my money is on this exact thing happening. It'd explain the inconsistent results we've seen so far.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#214

Post by callalex »

refulgentis wrote: post #200
callalex wrote: post #184

Earlier quoted context omitted.

What prediction markets are you looking at? Are there any concrete examples of these markets being accurate, or just a venue for gambling addicts to feel smart?

One prediction market company spent a day spamming e v e r y tweet with a link to their own stuff, so it's adopted a meme-y link to LK-99 but it's honestly unrelated other than a clever marketing campaign

My question is also broader than LK-99, and my point still stands.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#215

Post by saberdancer »

tootie wrote: post #186
saberdancer wrote: post #148

Earlier quoted context omitted.

I think most people are just seeing the headline 110K instead of realizing the implications (not a scam, not a mistake, hard to replicate). I was quite sceptical earlier today due to unconvincing videos but this finding pushes it heavily into "This might be it" territory.

I'm still unclear. Why is the test limit 110K? If this is supposed to be usable at ambient temperature then this seems like not a useful finding. Is it just some artifact of how superconductivity is measured?

Most materials are not superconductors at 110K. If this one is, it is possible Koreans did not fake room temperature results but rather their sample is slightly different for some reason, maybe pure luck, maybe some part of process that they didn't clearly define or that their precursor materials have certain impurities.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#216

Post by crazygringo »

modeless wrote: post #121

To me this is encouraging. 110K is really high! It's higher than YBCO which is what they make commercial "high temperature" superconducting tape out of. IMO if this is legit (I have no way of judging the source) then this is the first good third party evidence that the original researchers are not just doing some kind of fraud. A total fraud wouldn't have actually discovered a novel high-temperature, but not room tem…

> I'm surprised the prediction markets don't seem to be reacting.

Where can we look at prediction markets on this? For those of us who aren't familiar.

I'm very curious -- because unlike sports scores or political elections, this seems like such a hard thing to define a prediction market around, because what is the exact threshold you're defining and what is the threshold of proof of that thing and on what date is that decided?

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#217

Post by trafficante »

golol wrote: post #192
tootie wrote: post #186

Earlier quoted context omitted.

I'm still unclear. Why is the test limit 110K? If this is supposed to be usable at ambient temperature then this seems like not a useful finding. Is it just some artifact of how superconductivity is measured?

The common understanding seems to be that producing true LK99 is very difficult as you need to get the crystal structure just right. Many samples probably have mixes of the correct and other structures. That's why some float and some don't. The sample might be quite "dirty", meaning the critical temperature is lower.

Seems like it may depend on getting specific binding sites.

> 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. [1]

1. https://arxiv.org/abs/2307.16892

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#219

Post by zamalek »

gchadwick wrote: post #14

Certainly no expert here but if you take the original video and replications at face value it does exhibit strong diamagnetism at room temperature. Superconductors are diamagnetic due to the Meissner effect at their superconducting temperature. This would mean LK99 is a superconductor at low temperature and separately be strongly diamagnetic at room temperature (no Meissner effect if it's not super conducting). Would…

The strength of the diamagnetism would be extremely anomalous if it were not a superconductor, and would need new physics/names - super-diamagnetism or something (which itself would still be very useful). The chances of it being new physical phenomena is vanishingly small - we're almost definitely seeing superconductivity at STP with this degree of diamagnetism.

Re: LK-99: Team of Southeast University observed zero resistance below 110 K

#220

Post by [deleted] »

saberdancer wrote: post #215
tootie wrote: post #186

Earlier quoted context omitted.

I'm still unclear. Why is the test limit 110K? If this is supposed to be usable at ambient temperature then this seems like not a useful finding. Is it just some artifact of how superconductivity is measured?

Most materials are not superconductors at 110K. If this one is, it is possible Koreans did not fake room temperature results but rather their sample is slightly different for some reason, maybe pure luck, maybe some part of process that they didn't clearly define or that their precursor materials have certain impurities.

[deleted]
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