This is obviously a quickly produced paper to get the finding out but.... I find there to be so much missing and so many things poorly worded or posed about their process that would have taken zero time to expound upon, it's infuriating.
"All the reactions are carried out under 10^-2 Pa"
OK, I know they mean 10^-2 of vacuum. But why not say that? "10^-2 Pa" isn't enough. Was this a full vacuum oven? Done in sealed quartz vials? Was there a purge, like argon, or just air?
If you look at the oven temperature profiles, you can see the ramp up time (0-2hr, 0-2hr, and 0-4hrs respectively), and the hold time, but the ramp down time isn't specified! There is no cooling rate, it just shows... a line drop off, with no end time. No label. This can be very critical. Were these just pulled straight out and air quenched? And were they kept under vacuum until at room temp or not?
Like, adding extra experimental setup details would take no time whatsoever to include in a paper and yet these researchers just don't do it. It's either pure fucking laziness or some sorta holier-than-thou gatekeeping that comes from theoreticians, or a combination, and it is the reason that replication is so hard in science right now. I would hope that no journal would accept this shit.
I agree, it could use more of the easy details, however, I don't have much issue with 10^-2 Pa, since standard atmospheric pressure is 101,325 Pa, so 0.1 Pa (10^-2 Pa, or 1.45x10^-6 psi) is definitely understood as a vacuum, but you're correct, why not just add "vacuum" for thoroughness.
I know mercury gauges use to have a 0 to 30 scale sometimes (not 0 to -30), and that was confusing!
There is intense pressure to publish as many papers as possible at Chinese universities. This has led to a big problem of faked or just bad research papers coming out of China, so people are generally skeptical of them
Your point is fair.
It feels it also underlies the importance of "continuous teaching and learning", global (or assigned) peer reviewing.
At moments in time where discoveries like this one happen, one could hope that beyond "open publishing" like Arxiv, comes a true "science in the open", with room for cooperation.
Looking forward evolving further our current system.
The last week reminds me of the story of Bardeen & Brattain's invention of the transistor (e.g. in The Idea Factory). It barely worked and heaven forbid you bump the table. There was even a third slighted figure who wanted credit. Part of me wants to be skeptical but OTOH if it's hard to reproduce that seems totally normal. How exciting that some other people have got it working now.
Things also tend to be invented at about the same time at different places. I wonder if there are other people who were this close to invent it but just couldn't get it right.
Last year I read The Double Helix and The Code Breaker within a few months of each other, and what really stood out to me is that while we celebrate the first person who discovers something, in reality there were several teams all racing to the finish line, and were sometimes days or only even hours behind in presenting their findings. Yet only one team gets the accolades and their names in textbooks, the others are a mere footnote at best.
This was my first time reading about the history of discoveries like this, and I guess prior I thought these celebrated names had moved humanity forward by decades if not centuries by connecting the dots of the runes of the universe, but the reality is really very different.
Yeah, looks like it works that way mostly - based on the examples written up in "How Innovation Works: Serendipity, Energy and the Saving of Time" by M Ridley (https://www.amazon.co.uk/How-Innovation-Works-Matt-Ridley/dp...). Having done some R&D myself I tend to think of re-search as "repeated search for something that works" these days. Luck (or lack of) plays a big role too, the circumstances and the personalities of the actors involved likewise. Another book on a similar theme (but for medicine specifically) that I really enjoyed reading is "Happy Accidents: Serendipity in Major Medical Breakthroughs in the Twentieth Century" by MA Mayers (https://www.amazon.co.uk/Happy-Accidents-Serendipity-Breakth...).
Apparently the theory behind LK-99 was inspired by the studies from Eastern European scientists. However, after the Soviet collapse, the study was lost.
Funny enough Bardeen went on to work out the theory of conventional superconductivity later (with two other researchers) and got another Nobel prize out of it. What's your issue with Shockley btw?
Nobody can pick fights with Shockley any more (he's dead) - but Shockley is almost a household name, and Bardeen/Brattain's aren't. It's worth trying to adjust the record, both because Shockley was an abusive jerk and because he gets more credit than is due for the transistor.
(I'm not denying that Shockley was brilliant and effective.)
Why are folks trying to prove that this material is a superconductor in roundabout ways, like levitation, dimagnetism, etc? What is the reason they don't just test to see if electrical current flows without resistance? Surely there is something I am missing here.
With the current fabrication process, they're only getting a chunk with LK-99 particles sprinkled in. Since nobody yet knows how to fabricate a pure chunk of LK-99, it'll be hard to measure the true resistance of LK-99.
>Most likely, the material LK99 as reported in [1-3] is a heterophase structure, with co-existent non-superconducting constituents. This may yield superconducting droplets surrounded by nonsuperconducting material...
>In fact, I find that Cu on this Pb(2) is 1.08 eV more energetically favorable than Cu on the Pb(1) site, suggesting possible difficulties in robustly obtaining Cu substituted on the Pb(1) site.
The paper from Dr. Griffin at LBNL suggests copper atoms have to be placed in a specific (but less likely) position in the molecule to result in the desired flat band characteristic. Also, the original authors and the labs who were able to replicate LK-99 are reporting they had to make multiple batches to even find a tiny piece that shows levitation. This suggests that you just have to be very lucky to produce a sample with high enough concentration of LK-99 to observe levitation.
If we can somehow confirm that LK-99 is truly a room temperature superconductor, billions of dollars of R&D fund will pour in to improve the fabrication process. When the first transistor was invented, people probably weren't imagining that we'll be mass producing them in nanometer scale in the future. Or maybe LK-99 will be stuck in a lab like graphene. Who knows?
How do you explain the almost three orders of magnitude drop in resistance in Fig. 6d in one of the original articles ( https://arxiv.org/pdf/2307.12037.pdf ) with a few LK-99 particles sprinkled here an there? There must be a current path along which more than 99.8% of the material is in the supposed superconducting state. So the particles almost touch but not quite yet?
I think the more likely explanation is that the particles do touch each other but the interface is not superconductive. In other words, it is a polycrystalline material, and most of it is LK-99, but the grain boundaries are not a very good conductor. In conventional superconductors grain boundaries don't disrupt superconductivity because they are 3D superconductors, but in this allegedly 1D superconductor the superconducting channels in most cases don't meet at the grain boundaries, so the current has to overcome the resistance of some material that is almost an insulator.
If that is the case it will be difficult to produce a material that is macroscopically superconducting. But I hope researchers will be able to make single crystals that are large enough for resistance measurements so that finally it can be determined if this material is a superconductor or not. For practical uses the best result that can be achieved with this material may be a metal-LK-99 composite where the LK-99 particles lower the resistivity of the metal by 50-90%.
I believe that with the synthesis method proposed by the Korean team, i.e. by the chemical reaction between a certain kind of lead sulfate with copper phosphide, the chances of progress are slim.
The Korean team appears to have been stuck for several years by the lack of reproducibility of this synthesis method. While it was a great discovery that has shown that this material must have some very interesting properties, perhaps even superconductivity at ambient temperature and pressure, in order to be able to measure its properties and be able to evaluate the possible practical applications, a much more precise method for enforcing the desired crystal structure is required, than mixing powders and baking them into a ceramic.
Perhaps such a method for producing samples with deterministic properties would be to develop first a method to grow monocrystals of the special kind of lead phosphate that forms the base crystal structure, maybe by drawing the crystals from melt.
Once monocrystals of this kind of lead phosphate are available, they could be doped with copper, e.g. by ion implantation. By controlling and varying the parameters of the process, e.g. the angle of incidence and the velocity of the ions and the thermal profile used for annealing, it is likely that reproducible samples can be produced, where the copper ions substitute lead in the useful places and not in the others.
By this method it would be possible to produce only thin layers of LK-99, but that should be enough to enable the characterization of the material.
Moreover, because LK-99 is very fragile, it is unlikely that it could be used to make cables or coils. Practical uses where LK-99 would be deposited as thin films are much more likely.
As an alternative to ion implantation, which might be able to produce thicker layers, perhaps once monocrystals of the base lead phosphate are available it may be possible to develop some method of chemical vapor deposition, to grow epitaxially a layer of LK-99 over the base crystal, but with such a method it is less obvious if there is any way to control which lead atoms are substituted, though this may depend on the orientation of the base crystal.
I have heard people much more knowledgeable than me say that measuring true zero resistance is actually quite difficult and takes some degree of specialized equipment, especially with such small samples. That may be part of it.
Just getting the probes to connect reliably is tricky. depending on how large the superconducting features are it may be anywhere from just difficult to next to impossible to do accurately (for instance, if the size of the superconducting features is smaller than the probe size).
Right, if our best regular conductors (used in your ohmmeter) are ~10^-8 and superconductivity is (by convention) less than 10^-11, one can see right away the simple regular methods won’t work and some cleverness is needed.
That's right. The standard way to measure resistance without being sensitive to contact resistance is called the four-terminal method, see (https://en.m.wikipedia.org/wiki/Four-terminal_sensing). You drive a current using two outer wires, but then detect the voltage across the sample using a different pair of wires. You'll measure zero voltage if it's superconducting, since V=IR. Or if one of the probe wires became detached.
The first LK-99 paper used this method to claim zero resistivity, but people complained that if the inner probes lost contact, that would also be consistent with their data. This criticism doesn't totally make sense to me, since the apparent superconductivity came and went in the expected way as they changed an external magnetic field. I don't understand how a loose terminal could mimic that figure (I think it was in figure 1).
> a badly attached probe could also result in zero resistance for example
No, a badly attached probe would usually show a larger resistance, not a
smaller one. That's actually the easiest error to make, making improper contact with the sample. The resistance is measured indirectly using a reference
current. So you'd measure a higher resistance or a break rather than
zero if a probe were not attached correctly (unless the two voltage
probes are touching but that would normally speaking be spotted).
The diamagnetism is simply easier to verify using an impure or small sample.
My understanding is that synthesis of the exactly right crystal structure is very hard (for every 10 lead atoms, 1 - the exact right one - needs to be substituted with copper), so the samples are small and inhomogeneous. As a result measuring resistivity won't be illuminating until large amounts of perfect material can be produced.
Because (like someone explained very well in another HW notice) you can't measure zero ohms. Any device to measure resistance ALWAYS would have a minimal value that can measure. It's far more easy to detect superconductivity using the weird things that does all superconductors in presence of magnetic fields (ie, levitation).
They do both. But measuring the resistance of something that is that small is super hard because it will be close to zero anyway even if it isn't superconducting. So a larger sample would give much more conclusive results.
Without being intentionally snarky, the same logic applies to measuring current and voltage. What is observed is an effect of zero resistance, not zero resistance itself (whatever that would mean).
The korean guy say this is a 1d superconductor (as opposed to 2d sheet or 3d, which means you would need a single line of superconducting molecules from end to end. Its likely why it doesn't float all the way as only parts of it has these and scattered all over the chunk of solid.
However, if they perfect 1d production, they can layer in a bunch of them to create a quasi 2d or 3d superconductor.
The paper shows a clear phase transition to diamagnetism as the material is cooled. That would be seen in superconductors and not in regular diamagnetic materials. I'm not aware of any that have that kind of phase transition. Though since we're in weird territory here, it's important to note some weird non-superconductor behavior that's beyond regular diamagnetism might be going on as an alternative explanation. But it is weird.
ETA: also, in the presence of a magnetic field, that transition temperature decreases. That's pretty huge. Unless this paper is fraudulent, I take this as the biggest positive evidence so far that something besides simple diamagnetism is going on. And, cards on table, with the assumption that the paper is not fraudulent, this pushes my odds above 50% for the first time.
Magnetic transitions as a function of temperature are not unheard of, and it makes sense for them to depend on external field (they are magnetic after all). Lanthanum cobaltite for example has transition from diamagnet to paramagnet, likely due to change of spin state (see, e.g., [1]). I'm not saying that's what's happening, but transition (if it is there, hastily written papers tend to have subtle inaccuracies) doesn't rule out non-SC diamagnetism
First it shows a temperature graph vs moment, as they heat it it loses the diamagnetism around the temperature LK99 is said to be superconducting.
Second only a superconductor will have net-zero field, which means "stable" levitation. In the video they approach the sample with the magnet and flip it while the piece is mostly "in place". A regular diamagnet generates a external field that "follows" the field applied so it would likely move sideways, that is why to "levitate in place" a diamagnet people normally use a Halbach array.
EDIT: A Halback array is made alternating the poles N-S of the magnet, so that forces of repulsion created by the diamagnet cancel. This is why you will see people using multiple magnets when levitating pyrolytic graphite.
They have quantitative magnetization-versus-temperature data taken using a PPMS (an automated physical property measurement system). It shows strong evidence of some kind of diamagnetic transition at ~ 320K. It seems very likely now that this material has some kind of interesting magnetic property, whether or not it's due to superconductivity.
Noob question: if whatever is happening is strong enough to raise one of the ends of the sample, why doesn't raise both? After all gravitation is many order of magnitudes weaker than electromagnetism. Did they calibrate the setup to closely match the gravitational force on the sample? Why not push a little more and make it fly up the the cap of the container?
Magnetic force scales as 1/r^3, not 1/r^2 like gravity. That's why your standard issue fridge magnet measurably attracts stuff only from a very close distance, but when it does, it easily counters the gravitational attraction of the entire planet¹. This 1/r^3 relationship can be derived easily enough by integrating, but essentially it's because magnets are dipoles and the farther away you are, the smaller the apparent distance between the poles and the "more neutral" the magnet looks like.
Anyway, that's why there's an equilibrium distance where the forces balance. But superconductors also exhibit a very strange phenomenon called flux pinning [1] where a levitating object is held in place by magnetic field lines and you can even turn the whole thing upside down and it still levitates even though the forces don't cancel each other out anymore!
Nice! For show, I would try to levitate. Probably using a stronger magnet, inside a small (tiny?) glass tube, so it slides up a bit. I wouldn't do "rock surgery" just yet, to remove dead weight. Levitation with 4 magnets in a checkboard fashion, as usually done for pyrolytic carbon sheets, maybe doesn't work as the sample is not flat.
Also, turning the magnet upside down seems useful. And then, heating up to show that it drops at a certain temperature. I wonder what would be needed in this case; I guess less than 100° C.
In any case, the "show" part is important. Good video quality is important.
Reading further below, I'm actually amazed by all the theoretical studies that have already been done from first principles (all apparently supporting the possibility of superconductivity). That's a pretty fast pace for science!
Magnus Carlson said that if you tell him there’s a winning move on a chess board he could find it very quickly, because his focus becomes extremely narrow.
I wonder if something similar is happening here. Since the scope was defined as LK-99, it becomes a narrow query instead of a broad one.
This is the first time in years where I physically have goosebumps the more this seems to be verified. In a good way.
The potential changes this can introduce is equivalent to when Faraday, Volte, and all the other 17th/18th century scientists started figuring out how electricity works. They had no idea how much it would change every aspect of life in the century to come after them.
There is a reason why room temperature (ambient pressure) superconductors have been one of the holy grails of physics for such a long time: the implications are profound.
I used to be a particle physicist, and some of the more complex systems were just those used to cool the superconducting magnets down to cold enough that they become superconducting. If you can do that at ambient temp, you don't have to bother with that entire system.
Also: fusion reactors rely on superconducting magnets (or if you are JET live with the fact that you can only run your magnets for a few seconds before the overheat), so can have a large impact on future fusion reactors.
I get the idea of superconductivity at room temperature in theory. But I don't have enough knowledge to understand in real terms, how will the world change if this is true?
You can't get CT scans very often, because they hit you with large doses of ionizing radiation. Ultrasounds are low-resolution spotlights; you shine them at a particular spot to diagnose something specific.
With this you could get an MRI at your annual checkup. You could diagnose all number of diseases like that, not to mention 95% of cancers. Each year your scan is automatically compared to the previous year, and any sudden changes in morphology can be biopsied. The learning would be revolutionary for medical science as well- right now we have so little data on what kinds of benign growths people have that our best method for figuring out if a mass is a problem is asking if there are any other symptoms. Not to mention entirely new kinds of medical devices would be possible, eg using SQUIDs.
Ground-imaging MRI would also be revolutionized. Archeology, paleontology, geology, mapping resources and finding minerals would experience a quantum leap. You would be able to drive a car through the desert and spot fossils or faults or mineral signatures.
Space travel would become essentially free with the use of launch loops. Which would also make long-distance travel incredibly cheap and practically pollution-free. You would need electricity alone to reach low earth orbit, or to accelerate planes to multiples of the speed of sound.
Grid-level storage, peaker plants and load-following would become nearly obsolete. Superconducting catenaries would connect every nation on earth. Normally plants have to turn off when everyone goes to sleep; now factories in China can be powered by US fission. Canadian homes could be kept warm by Australian solar. HVDC interlinks would be obsolete. We might eventually transition away from AC power entirely.
CPUs could be anywhere from 10% to 50% more efficient. GPUs even more so. Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.
> We might eventually transition away from AC power entirely.
This is actually a really good point I hadn't fully considered, but it's right: the primary reason we use high voltage anywhere is because it minimizes resistive losses (and the reason we use AC is because it's easy to transform between voltages).
But most of the stuff in my home doesn't need high voltage - it's all running at 5V or 12V. Or it's a motor which is magnetically driven and depends solely on magnetic field strength (which is independent of voltage).
If all your conductors have zero resistance, then high voltage is obsolete. You could safely run a residential property on 12V power. Home electrical hazards would a thing of the past.
Full body MRI scans are only expensive in the West, outside the west you can get one done for $250. This is a labor and regulatory capture problem and not a technology problem and will not be affected in any meaningful way by better superconductors.
> Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.
I don't know enough about how this material behaves, but a superconductor "quench"* can be pretty catastrophic. I could see a room temperature superconductor battery causing fires from a quench.
we could do annual scans with current tech. the fundamental limitation of MRI is proton relaxation time, which limits the sampling rate. the path to reducing scan time and thus cost is to use a more sophisticated reconstruction method to reduce the number of required samples. this is being worked on.
i don't have any data here, but I am dubious that a room temperature superconductor will bring down the price of MRI machines. a room temp superconductor only saves you a dewar, about $50k of liquid helium and a cryocooler. you still have to build the rest of the MRI, which is an _extraordinarily_ sensitive instrument
> Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.
If feasible and indeed not as expensive to produce these materials, high potential for:
- higher efficiency turbines and solar panels - more clean energy for the same investment
- fusion?
- low-energy computing at higher performance, as we learned recently LLMs so far can't take advantage of hitherto zero marginal cost of software anymore
- democratization of advanced quantum computing?
It's all very exciting and in a truly replicable and industrially-feasible scenario I'm starting to feel this could be another 1960s kind of rate of change. One can dream, no? Maybe we can finally get rid of all the doom & gloom stories we tell ourselves and actually do something with these unexpected presents of our times? Think smartness instead of ignorance, (old) Star Trek instead of the latest Fallout fantasy on the horizon? Why not?
These and many more consequential innovations might develop just in time, as climate change is coming at us much faster than we are willing to admit (don't look up).
That said, even with all of that (including fusion) we will still need to cut our co2 emissions; drastically change our lifestyles / minimize consumption and deal with already locked in impacts hitting us sooner than later.
Enthusiastic midnight edit:
Also what's up with graphene based ICs and optical computing advancements? Competition of new old ideas finally come to be realized? What's next? I want a new breed of superconductor enabled Lisp Machines by 2030! Why not home brew "3D print" the whole thing? That should be the ultimate target here! The handling of "open source" lead would probably suck though %D.
I guess Alan Kay wouldn't be enthused by such a Lisp Machine renaissance in principle yet still stand with his "the best way to predict the future is to invent it" credo.
Let's predict a future for a planet that shifts back into balance!
You know all those bird scooters people leave lying around cluttering up the sidewalk? With a room temperature superconductor they will become hover scooters cluttering up the sidewalk!
And all of the high voltage transmission lines we want to build but can’t because of permitting reasons would have zero energy loss if we actually built them, which we won’t.
I don't think anybody can really say for now, but if the price of it comes down enough, there are two rough categories of things that can happen:
* devices that currently use superconductors don't have to use cooling anymore, and so become much cheaper to build and operate (MRI machines, certain sensors, high-power magnets for things like fusion research, big generators, big motors). This is a pretty solid bet.
* devices where superconductors would be an improvement, but currently don't make economic or practical sense. These are almost certain to crop up, but which ones will pan out is IMHO very speculative.
In the latter category, things like computing chips, more sensors, certain art works (sculptures with permanently levitating parts, how awesome!), smaller motors and generators seem plausible.
But there is likely whole categories of things we haven't thought of that could benefit from either zero resistance or rejecting magnetic fields.
It means we won't lose MRIs when the earth finally runs out of helium as they require liquid helium to run the superconductors that generate the magnetic field. We're running out of helium with no way to replenish it. Helium is the only element on the periodic table which is a non-renewable resource on Earth.
So MRIs will get much cheaper, and they could end up being as cheap as taking an x-ray today.
Based on our current data LK99 isn't a replacement for helium cooled superconductors for the same reason YBCO and similar aren't - critical current/critical magnetic field aren't in the right ranges for what we need out of MRI machines.
I do think it's too early to say one way or the other what all of this ends up looking like, so we might find that purer/larger samples have better properties than what was measured so far, or the discovery puts us on the trail of other RTAPS in the same class that might be better for these purposes.
If the earth runs out of helium we will just use low field MRIs that don't require superconductors (see eg https://www.nature.com/articles/s41467-021-25441-6 ). Their resolution is lower than that of high field MRIs, but they still seem to be a useful diagnostic tool.
I suppose you could count elements like gold, too. Since we technically can produce extremely radioactive gold in small amounts but the cost is so prohibitive it would never make sense to.
In a thousand years people are gonna look back at us idiots filling balloons with helium and letting them disperse into the upper atmosphere and shake their heads at how stupid we were.
I think you mean lossless transmission? If we can actually replace transmission lines effectively with it, unclear whether it's practical for that yet.
I'm thinking coil guns instead. Room temperature superconductors don't solve the rail erosion issue with railguns, but I think should greatly increase the performance of coil guns.
My thinking is that zero resistance through the projectile itself and through the rails would help, but you still need to make an electrical connection between the projectile and the rails. Either this is done with a plasma arc or physical contact, but either of these causes erosion of the rails even if there is no electrical resistance through the rails or projectiles. Am I missing something?
Readit News
"All the reactions are carried out under 10^-2 Pa"
OK, I know they mean 10^-2 of vacuum. But why not say that? "10^-2 Pa" isn't enough. Was this a full vacuum oven? Done in sealed quartz vials? Was there a purge, like argon, or just air?
If you look at the oven temperature profiles, you can see the ramp up time (0-2hr, 0-2hr, and 0-4hrs respectively), and the hold time, but the ramp down time isn't specified! There is no cooling rate, it just shows... a line drop off, with no end time. No label. This can be very critical. Were these just pulled straight out and air quenched? And were they kept under vacuum until at room temp or not?
Like, adding extra experimental setup details would take no time whatsoever to include in a paper and yet these researchers just don't do it. It's either pure fucking laziness or some sorta holier-than-thou gatekeeping that comes from theoreticians, or a combination, and it is the reason that replication is so hard in science right now. I would hope that no journal would accept this shit.
I know mercury gauges use to have a 0 to 30 scale sometimes (not 0 to -30), and that was confusing!
and
https://twitter.com/8teAPi/status/1685294623449874432
The papers were totally rushed.
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Dead Comment
This was my first time reading about the history of discoveries like this, and I guess prior I thought these celebrated names had moved humanity forward by decades if not centuries by connecting the dots of the runes of the universe, but the reality is really very different.
Same for people looking at patents from other countries.
> What's your issue with Shockley btw
Well he was a mega racist, but that's not relevant
Nobody can pick fights with Shockley any more (he's dead) - but Shockley is almost a household name, and Bardeen/Brattain's aren't. It's worth trying to adjust the record, both because Shockley was an abusive jerk and because he gets more credit than is due for the transistor.
(I'm not denying that Shockley was brilliant and effective.)
https://arxiv.org/abs/2308.01723
>In fact, I find that Cu on this Pb(2) is 1.08 eV more energetically favorable than Cu on the Pb(1) site, suggesting possible difficulties in robustly obtaining Cu substituted on the Pb(1) site.
https://arxiv.org/abs/2307.16892
The paper from Dr. Griffin at LBNL suggests copper atoms have to be placed in a specific (but less likely) position in the molecule to result in the desired flat band characteristic. Also, the original authors and the labs who were able to replicate LK-99 are reporting they had to make multiple batches to even find a tiny piece that shows levitation. This suggests that you just have to be very lucky to produce a sample with high enough concentration of LK-99 to observe levitation.
If we can somehow confirm that LK-99 is truly a room temperature superconductor, billions of dollars of R&D fund will pour in to improve the fabrication process. When the first transistor was invented, people probably weren't imagining that we'll be mass producing them in nanometer scale in the future. Or maybe LK-99 will be stuck in a lab like graphene. Who knows?
I think the more likely explanation is that the particles do touch each other but the interface is not superconductive. In other words, it is a polycrystalline material, and most of it is LK-99, but the grain boundaries are not a very good conductor. In conventional superconductors grain boundaries don't disrupt superconductivity because they are 3D superconductors, but in this allegedly 1D superconductor the superconducting channels in most cases don't meet at the grain boundaries, so the current has to overcome the resistance of some material that is almost an insulator.
If that is the case it will be difficult to produce a material that is macroscopically superconducting. But I hope researchers will be able to make single crystals that are large enough for resistance measurements so that finally it can be determined if this material is a superconductor or not. For practical uses the best result that can be achieved with this material may be a metal-LK-99 composite where the LK-99 particles lower the resistivity of the metal by 50-90%.
The Korean team appears to have been stuck for several years by the lack of reproducibility of this synthesis method. While it was a great discovery that has shown that this material must have some very interesting properties, perhaps even superconductivity at ambient temperature and pressure, in order to be able to measure its properties and be able to evaluate the possible practical applications, a much more precise method for enforcing the desired crystal structure is required, than mixing powders and baking them into a ceramic.
Perhaps such a method for producing samples with deterministic properties would be to develop first a method to grow monocrystals of the special kind of lead phosphate that forms the base crystal structure, maybe by drawing the crystals from melt.
Once monocrystals of this kind of lead phosphate are available, they could be doped with copper, e.g. by ion implantation. By controlling and varying the parameters of the process, e.g. the angle of incidence and the velocity of the ions and the thermal profile used for annealing, it is likely that reproducible samples can be produced, where the copper ions substitute lead in the useful places and not in the others.
By this method it would be possible to produce only thin layers of LK-99, but that should be enough to enable the characterization of the material.
Moreover, because LK-99 is very fragile, it is unlikely that it could be used to make cables or coils. Practical uses where LK-99 would be deposited as thin films are much more likely.
As an alternative to ion implantation, which might be able to produce thicker layers, perhaps once monocrystals of the base lead phosphate are available it may be possible to develop some method of chemical vapor deposition, to grow epitaxially a layer of LK-99 over the base crystal, but with such a method it is less obvious if there is any way to control which lead atoms are substituted, though this may depend on the orientation of the base crystal.
Showing diamagnetism is one of the least error-prone ways to demonstrate the superconductor effect.
That’s my understanding anyway.
The first LK-99 paper used this method to claim zero resistivity, but people complained that if the inner probes lost contact, that would also be consistent with their data. This criticism doesn't totally make sense to me, since the apparent superconductivity came and went in the expected way as they changed an external magnetic field. I don't understand how a loose terminal could mimic that figure (I think it was in figure 1).
No, a badly attached probe would usually show a larger resistance, not a smaller one. That's actually the easiest error to make, making improper contact with the sample. The resistance is measured indirectly using a reference current. So you'd measure a higher resistance or a break rather than zero if a probe were not attached correctly (unless the two voltage probes are touching but that would normally speaking be spotted).
The diamagnetism is simply easier to verify using an impure or small sample.
However, if they perfect 1d production, they can layer in a bunch of them to create a quasi 2d or 3d superconductor.
Back then, many asked if this was superconduction or merely diamagnetism. Does the new paper shine any light on this question?
ETA: also, in the presence of a magnetic field, that transition temperature decreases. That's pretty huge. Unless this paper is fraudulent, I take this as the biggest positive evidence so far that something besides simple diamagnetism is going on. And, cards on table, with the assumption that the paper is not fraudulent, this pushes my odds above 50% for the first time.
[1] https://www.sciencedirect.com/science/article/abs/pii/S09258...
Time for you to make some money then? :D
https://polymarket.com/event/is-the-room-temp-superconductor...
First it shows a temperature graph vs moment, as they heat it it loses the diamagnetism around the temperature LK99 is said to be superconducting.
Second only a superconductor will have net-zero field, which means "stable" levitation. In the video they approach the sample with the magnet and flip it while the piece is mostly "in place". A regular diamagnet generates a external field that "follows" the field applied so it would likely move sideways, that is why to "levitate in place" a diamagnet people normally use a Halbach array.
EDIT: A Halback array is made alternating the poles N-S of the magnet, so that forces of repulsion created by the diamagnet cancel. This is why you will see people using multiple magnets when levitating pyrolytic graphite.
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https://twitter.com/andrewmccalip/status/1687405505604734978
Anyway, that's why there's an equilibrium distance where the forces balance. But superconductors also exhibit a very strange phenomenon called flux pinning [1] where a levitating object is held in place by magnetic field lines and you can even turn the whole thing upside down and it still levitates even though the forces don't cancel each other out anymore!
[1] https://en.wikipedia.org/wiki/Flux_pinning
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¹ To be fair, "the entire planet" is also around 6000 km away, calculation-wise, but still!
Also, turning the magnet upside down seems useful. And then, heating up to show that it drops at a certain temperature. I wonder what would be needed in this case; I guess less than 100° C.
In any case, the "show" part is important. Good video quality is important.
This Wikipedia article has a good summary of the replication attempts to date (including this paper).
I wonder if something similar is happening here. Since the scope was defined as LK-99, it becomes a narrow query instead of a broad one.
The potential changes this can introduce is equivalent to when Faraday, Volte, and all the other 17th/18th century scientists started figuring out how electricity works. They had no idea how much it would change every aspect of life in the century to come after them.
I used to be a particle physicist, and some of the more complex systems were just those used to cool the superconducting magnets down to cold enough that they become superconducting. If you can do that at ambient temp, you don't have to bother with that entire system.
Also: fusion reactors rely on superconducting magnets (or if you are JET live with the fact that you can only run your magnets for a few seconds before the overheat), so can have a large impact on future fusion reactors.
With this you could get an MRI at your annual checkup. You could diagnose all number of diseases like that, not to mention 95% of cancers. Each year your scan is automatically compared to the previous year, and any sudden changes in morphology can be biopsied. The learning would be revolutionary for medical science as well- right now we have so little data on what kinds of benign growths people have that our best method for figuring out if a mass is a problem is asking if there are any other symptoms. Not to mention entirely new kinds of medical devices would be possible, eg using SQUIDs.
Ground-imaging MRI would also be revolutionized. Archeology, paleontology, geology, mapping resources and finding minerals would experience a quantum leap. You would be able to drive a car through the desert and spot fossils or faults or mineral signatures.
Space travel would become essentially free with the use of launch loops. Which would also make long-distance travel incredibly cheap and practically pollution-free. You would need electricity alone to reach low earth orbit, or to accelerate planes to multiples of the speed of sound.
Grid-level storage, peaker plants and load-following would become nearly obsolete. Superconducting catenaries would connect every nation on earth. Normally plants have to turn off when everyone goes to sleep; now factories in China can be powered by US fission. Canadian homes could be kept warm by Australian solar. HVDC interlinks would be obsolete. We might eventually transition away from AC power entirely.
CPUs could be anywhere from 10% to 50% more efficient. GPUs even more so. Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.
This is actually a really good point I hadn't fully considered, but it's right: the primary reason we use high voltage anywhere is because it minimizes resistive losses (and the reason we use AC is because it's easy to transform between voltages).
But most of the stuff in my home doesn't need high voltage - it's all running at 5V or 12V. Or it's a motor which is magnetically driven and depends solely on magnetic field strength (which is independent of voltage).
If all your conductors have zero resistance, then high voltage is obsolete. You could safely run a residential property on 12V power. Home electrical hazards would a thing of the past.
I don't know enough about how this material behaves, but a superconductor "quench"* can be pretty catastrophic. I could see a room temperature superconductor battery causing fires from a quench.
*: https://en.wikipedia.org/wiki/Superconducting_magnet#Magnet_...
i don't have any data here, but I am dubious that a room temperature superconductor will bring down the price of MRI machines. a room temp superconductor only saves you a dewar, about $50k of liquid helium and a cryocooler. you still have to build the rest of the MRI, which is an _extraordinarily_ sensitive instrument
> Fires, particularly house fires would become less common as wires simply stop conducting when they are overloaded.
depends how sharp the phase transition is.
- higher efficiency turbines and solar panels - more clean energy for the same investment
- fusion?
- low-energy computing at higher performance, as we learned recently LLMs so far can't take advantage of hitherto zero marginal cost of software anymore
- democratization of advanced quantum computing?
It's all very exciting and in a truly replicable and industrially-feasible scenario I'm starting to feel this could be another 1960s kind of rate of change. One can dream, no? Maybe we can finally get rid of all the doom & gloom stories we tell ourselves and actually do something with these unexpected presents of our times? Think smartness instead of ignorance, (old) Star Trek instead of the latest Fallout fantasy on the horizon? Why not?
These and many more consequential innovations might develop just in time, as climate change is coming at us much faster than we are willing to admit (don't look up).
That said, even with all of that (including fusion) we will still need to cut our co2 emissions; drastically change our lifestyles / minimize consumption and deal with already locked in impacts hitting us sooner than later.
Enthusiastic midnight edit:
Also what's up with graphene based ICs and optical computing advancements? Competition of new old ideas finally come to be realized? What's next? I want a new breed of superconductor enabled Lisp Machines by 2030! Why not home brew "3D print" the whole thing? That should be the ultimate target here! The handling of "open source" lead would probably suck though %D.
I guess Alan Kay wouldn't be enthused by such a Lisp Machine renaissance in principle yet still stand with his "the best way to predict the future is to invent it" credo.
Let's predict a future for a planet that shifts back into balance!
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All i want is a maglev hot wheels track using flux pinning.
Just imagine all the cool toys a room temp semiconductor would enable.
And all of the high voltage transmission lines we want to build but can’t because of permitting reasons would have zero energy loss if we actually built them, which we won’t.
* devices that currently use superconductors don't have to use cooling anymore, and so become much cheaper to build and operate (MRI machines, certain sensors, high-power magnets for things like fusion research, big generators, big motors). This is a pretty solid bet.
* devices where superconductors would be an improvement, but currently don't make economic or practical sense. These are almost certain to crop up, but which ones will pan out is IMHO very speculative.
In the latter category, things like computing chips, more sensors, certain art works (sculptures with permanently levitating parts, how awesome!), smaller motors and generators seem plausible.
But there is likely whole categories of things we haven't thought of that could benefit from either zero resistance or rejecting magnetic fields.
So MRIs will get much cheaper, and they could end up being as cheap as taking an x-ray today.
I do think it's too early to say one way or the other what all of this ends up looking like, so we might find that purer/larger samples have better properties than what was measured so far, or the discovery puts us on the trail of other RTAPS in the same class that might be better for these purposes.
An Earth-sized MRI machine could image all of the remaining mineral deposits, and it coils could make for a hell of an autobahn.
In a thousand years people are gonna look back at us idiots filling balloons with helium and letting them disperse into the upper atmosphere and shake their heads at how stupid we were.
My thinking is that zero resistance through the projectile itself and through the rails would help, but you still need to make an electrical connection between the projectile and the rails. Either this is done with a plasma arc or physical contact, but either of these causes erosion of the rails even if there is no electrical resistance through the rails or projectiles. Am I missing something?