11 ms·
Origin of correlated isolated flat bands in LK99
- TillE 3y ago"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" OK I'm starting to actually believe that LK-99 might be the real deal.
- elfbargpt 3y agoCan anyone explain what this means in relation to the ability to synthesize it in superconducting form? Is there a way to force the Cu to the correct site? Or is looking for a new material with similar properties the way forward
- yinser 3y agoI’m currently in a Twitter space with some accounts who know more about this process and this question was answered a few minutes ago. To summarize: no one has yet found a way to “steer” which sites get Cu and which ones don’t. This paper simultaneously makes LK-99 look like the real deal but also points out there may be more, or much more work, to reliably direct the replacement. Someone in the space said “if you find a way to get the Cu to the right site that’s a Nobel Prize”
- yinser 3y agoLink to the space, https://twitter.com/i/spaces/1eaKbrgVyoqKX https://twitter.com/i/spaces/1eaKbrgVyoqKX
- calf 3y agoIf some third party scoops a more reliable process that would seem unfortunate for the original group.
- nemo44x 3y agoI don’t think so, not at this point. Their foundational theory and experiments to objectively prove it are more than enough. Anything that follows could be too but it doesn’t diminish what these guys have discovered. There will be thousands of people working on this now. These guys are the shoulders they all stand on.
- KingLancelot 3y agoI mean, it’s the higher energy site, right? So heat it? Better yet, do something like a microwave oven tuned to Lead’s resonant frequency to encourage all the sites to be in the higher energy state as the crystal structure is forming.
- scythe 3y agoI'm not an expert on chemistry but it sounds like this would make it ridiculously hard to obtain a high quality sample. Copper can substitute for either lead site; I'm not aware of macroscopic processes that would favor one over the other. Problems like that are usually handled ad hoc. The authors seem to have bumped and shuffled their way there through the darkness. For context, the preparation of tetrataenite was pursued for decades (first partial success October 2022) even though the structure was well-known and the constituents are just nickel and iron.
- fnordpiglet 3y agoIt’s sort of an amazing time. All the things we projected were 30 years out 40 years later and manifesting. The degree of skepticism is high, as should be, but the things we knew were achievable just hard to discover are rapidly unfolding. What falls next? (N.b., I know I’m displaying unreasonable hubris and it’s still more likely than not an illusion or fabrication, but it certainly feels a lot of long term investments are rapidly coming to a head - AI, space, cancer treatments, aging research, EV, even flying cars and fusion - what a great time to be alive)
- dtx1 3y agoEven if LK99 turns out to be a dud, it's proven that there's a great need and great opportunity for more direct communication from scientist on their experiments via the internet. Live Stream of the Synthesis, Twitter Threads giving life updates of different teams, etc.
- mrandish 3y agoI fully agree that the traditional journal and academic publishing models are having significant negative impact on the conduct of science. I also really like that the Arxiv, open access publishing, open peer review, live science and similar new models represent a refreshing return to less gatekeeping, politics and institutional gamesmanship. Based on the early successes shown by applying social media platforms like Twitter, Twitch, Discord, etc, to accelerating science, I hope we can evolve better tools and platforms which are equally open but even more suited to the exchange of scientific ideas, results, review and feedback.
- wilg 3y agoI've always felt I love the idea of arXiv as a non-scientist who is interested in following science, but it's so esoteric and hard to follow (the density and format of scientific papers does not help). I would love something that was half arXiv and half-Twitter, and if papers were natively written for the web in an elegant and cross-linked way with rich explanations of related topics, interactive graphs with linked datasets, video, jargon explanations, etc.
- montecarl 3y agoMost science is way too boring and requires way to much work to reproduce to follow this kind of model. This open science type work we are seeing for LK-99 works fantastically when a huge number of scientists are interested in the problem and motivated to study it. Most papers aren't even cited more than a dozen times if that.
- npunt 3y agoAgree for sure, really love seeing the evidence and discussion in realtime as it shows us a better way to do worldwide science collaboration than traditional publishing. Really speaks to a need for a new medium specific to science's unique characteristics. One caveat tho is that hype can also distort and there's a limited resource of 'the public's excitement with science' that depletes if it never delivers, so I wouldn't necessarily couple science education/comms with science process so tightly. Most science is lots and lots of boring toil, and I'd hope the $$s flow to the best scientists rather than the ones who tell the most twitter-friendly stories.
- deleted 3y ago[deleted]
- bacon_waffle 3y agoThis paper is by someone from Lawrence Berkeley National Laboratory, who has run some simulations of LK99 and found features that are associated with high temperature superconductors. In the last paragraph before acknowledgements, they point to a feature that could make synthesis difficult, then conclude with "Nevertheless, I expect the identification of this new material class to spur on further investigations of doped apatite minerals given these tantalizing theoretical signatures and experimental reports of possible high-TC superconductivity." (I'm a high school dropout, worked for a physics project once)
- caesil 3y agoOut of curiosity, since this seems like a real inflection point toward trending in that direction, if it becomes increasingly likely that LK-99 or similar material is indeed a high-TC superconductor, what will savvy people be positioning themselves to do? What are good investments? What companies will be started, or what will existing companies be pivoting toward?
- m3kw9 3y agoDepends if this can scale, and can withstand environments and carry enough current density etc. If it’s brittle as f, then it limits its applications for example.
- dtx1 3y agoEven if it is, we can coat it in epoxy and deal with it. And even if we can't, remember the first semi-conductor was germanium. If we have a theoretical and practical reproducible RT Superconductor we will very fast find new, better ones.
- tnecniv 3y agoAnd audio nerds everywhere are still lusting after germanium transistors to this day!
- bick_nyers 3y agoCould you explain why? Sounds intriguing.
- jacquesm 3y agoSounds noisy...
- Ccecil 3y agoMy understanding is that it is due to the lower voltage drop across the base junction. Germanium is .3v vs Silicon .7v, so with germanium you get less "crossover distortion" when the input signal is crossing the 0 line. edit: I understand that typically this is biased out with diodes...but the matching is not perfect and it is easier to start with half the distortion.
- bibabaloo 3y ago"plain English" explanation: https://nitter.net/Andercot/status/1686215574177841152#m https://nitter.net/Andercot/status/1686215574177841152#m
- thepasswordis 3y agoDirect link: https://twitter.com/Andercot/status/1686215574177841152#m https://twitter.com/Andercot/status/1686215574177841152#m
- montenegrohugo 3y agoManifold markets jumped to ~40% likelihood (briefly around 60%) after this paper was published.
- whimsicalism 3y agoAs someone familiar with DFT, that is arbitrage opportunity:)
- montenegrohugo 3y agoDo it! Put your money where your mouth is and get ez $ (and help shape a more accurate estimate!)
- whimsicalism 3y agooh, I did :) - love me some yummy internet points e: oh wow holy crap manifold has a lot more liquidity than when I last checked in, sold for an easy profit now that I think it has returned to a more reasonable probability
- drones 3y agoEven if LK99 isn't the real deal, god has it been an exciting 2 weeks. Though I know absolutely nothing about material science, I have enjoyed the sheer enthusiasm and optimism the scientific community has shown. I feel like I'm part of something unique and special, something which could have only been achieved by the medium of accessible mass communication. The excitement here is palpable. I feel fortunate to be part of this infinitesimally miniscule portion of human history where I can share this moment with so many people.
- deleted 3y ago[deleted]
- SamPatt 3y agoI sometimes wonder what it would have been like to witness the emergence of fundamental new technologies, like electricity or radio. Then I remember I'm further along the tech tree than they were, and what a gift that is. It's very exciting to watch it update in real time. Now I'm envious of future generations (I think humanity has a bright future despite the current gloom groupthink).
- vasco 3y agoI was many times sad to not be in the future just to get more history to read and more ahead on the tech tree as you say. One of the most interesting things in life is the "story" of life itself. I don't mind not living later but I'd really like to know what happens!
- raziel2701 3y agoMan, I'm feeling stronger about LK-99 being it. This paper is theoretical and she finds that particular Cu substitutions onto specific Pb atomic sites are key to enabling a band structure that is usually linked to high Tc superconductors. What this means for the more practical minded is that the synthesis of superconducting LK-99 is not trivial and you need to make the appropriate substitutional alloy for this to work. This is a DFT paper, and a band structure that is usually seen in high Tc superconductors just naturally came out. She also talks about the strong electron-phonon coupling that naturally arose from the structure, which is always necessary for superconductivity. I am, by far, the most excited I've ever been about this being a RT, ambient pressure superconductor.
- bibabaloo 3y agoIf this could be simulated, can you help me understand why we couldn't have used simulation to find promising SC materials to investigate further earlier? Are there just too many permutations to investigate? It seems to my own naive self that if LK99 is the real deal, we mostly just got lucky finding it.
- ivalm 3y agoYou have to put in the structure and then it's expensive to do the calculation. The space of possible structures is extremely large. If you have candidates then you can run through them, but you can't just random search through trillions of trillions of candidates.
- justrealist 3y agoI really hope this unlocks a class of superconductors and isn't a bizarre oneoff compound, because the EPA of 2023 is not going to let us wire the country with thousands of miles of lead-based ceramic wire.
- abtinf 3y agoIf this material works out and EPA takes that stance, it will be the end of EPA. So they won’t take that stance.
- jychang 3y agoIf this material works out and also turns to be massively toxic, then people thinking the way you do is going to cause a lot of lead poisoning. Not fun.
- abtinf 3y agoI have not stated a view on whether the hypothetical material of unknown toxicity should be used or not. I am making a political claim that bureaucrats will behave in certain, highly predictable ways. If the material proves to be what it claims to be, it will not be banned. At most, it will be highly regulated, as that will preserve and expand government power.
- woeirua 3y agoThere is no way that miles of sheathed superconducting material would be more toxic than burning leaded fuel for decades.
- bigmattystyles 3y agoIsn’t lead ok as long as it’s not airborne/ ingested?
- justrealist 3y agohttps://www.wsj.com/articles/lead-cables-telecoms-att-toxic-5b34408b https://www.wsj.com/articles/lead-cables-telecoms-att-toxic-... Once the cable is laid, it's a liability.
- seewhydee 3y agoDon't get too excited --- theorists have predicted nine of the last five physics breakthroughs (pace Paul Samuelson).
- montecarl 3y agoTheory confirming experiment is quite different from theory predicting new physics. I think the best use of these types of ab initio DFT calculations is to interpret experimental results. Back in grad school, my theoretical chemistry group regularly was able to help clear up confusing experimental findings with these exact type of calculations (in fact using the same program as used in this paper, VASP).
- cubefox 3y agoIt's funny to read all those grammatical mistakes in the abstract. They are probably just not native English speakers, but to me it sounds like they were frantically typing the paper as soon as they finally got results after a 20 hour lab marathon and way too much caffeine. :D
- bawolff 3y agoIt isn't the prettiest prose i have ever read, but no obvious outright mistakes stick out to me. It doesn't read any worse than the average hn comment.
- zulmkodr 3y agoIf only they had a technical writer in their team
- alberto_ol 3y agoFrom her wikipedia page, Sinéad Griffin is an Irish physicist, so she seems a native English speaker https://en.wikipedia.org/wiki/Sin%C3%A9ad_Griffin https://en.wikipedia.org/wiki/Sin%C3%A9ad_Griffin
- return_to_monke 3y agoIn the original paper, so i assume the Lee-Kim ones
- cubefox 3y agoI wanted to comment on a paper by some different group. It's confusing with all those papers floating around on HN.
- cududa 3y agoWhat? So you didn't even click the paper being discussed here and just threw in a comment criticizing some entirely different person's mastery of english "I don't like the waiters in this restaurant" "Have you ever eaten here?" "Oh. No. I mean the other restaurant." "Which restaurant?" "I mean one of those other restaurants in town. Don't like 'em. They talk funny."
- yellowcake0 3y agoThere's a lot of optimism in this thread, but does DFT (or any theoretical model really) actually have much predictive value in quantum chemistry? I've always gotten the impression that in this field the proof is in the pudding.
- semajian 3y agoThere are so many bad DFT papers out there because it's cheap to do DFT compared to growing and measuring samples carefully. DFT is notoriously unreliable as a predictive tool in strongly correlated systems, though when electron correlations are small it works well. I mean, I want this to be true, but I put little stock in DFT that doesn't calculate observables. So yes, you're right.
- rex_lupi 3y agoAbsolutely, Came to say this.
- klyrs 3y agoExplaining why is valuable. The band gap described in this paper is common to other high temperature superconductors. While I remain skeptical, this gives a glimmer of hope, and if the material is indeed superconducting, analysis like this is useful in further understanding high temperature superconductors. If it's not superconducting, then this research may yet be interesting -- if the analysis is correct, it would be interesting to know what's different.
- rex_lupi 3y agoThe prof who taught us computational chemistry during masters basically said 90% of published results cannot be trusted and most people in this field don't really know what they're doing. Results can look seemingly good and stil be way off from reality, even for very simple molecules. This is a crystal lattice. I take dft and other computational results with a big grain of salt.
- jacquesm 3y agoBut it isn't used for its predictive value here, it is used to verify that which is already known (or at least, strongly suggested to be known). That's different than coming up with a compound based on some hunch, this is modeling a compound with a known structure to check that for properties consistent with the expectations. That's radically different from searching for a compound with particular properties, that is a much more error prone process.
- lambdasquirrel 3y agoI wonder how one would draw out a wire made of such a material. From the sound of it, the copper atoms have to be in the exact right place in the lattice. Wouldn't naively working with the alloy ruin the superconducting properties? Maybe an actual MatSci person would know.
- vermilingua 3y agoJust don't do it naively /s
- floxy 3y agoCurrent high-temperature superconductor tapes aren't drawn. The micron thick material is deposited on a substrate and baked. https://duckduckgo.com/?q=high+temperature+superconductor+tape+layers&iar=images&iax=images&ia=images https://duckduckgo.com/?q=high+temperature+superconductor+ta...
- Mockapapella 3y agoAl lot of people are hyped about this. Why? What, in a practical sense, does a room temperature superconductor enable for humanity?
- bibabaloo 3y agoThis thread covers some applications: https://twitter.com/Andercot/status/1685088625187495936 https://twitter.com/Andercot/status/1685088625187495936
- synaesthesisx 3y agoSomething incredible to note: it took around 5 years from when the transistor was first developed, to when it started to get integrated into consumer goods. LK-99 appears promising (and at the very least, may lead to other tangentially interesting discoveries), and if this is “it”, we could see commercial applications far sooner, especially if the synthesis is relatively straightforward. We couldn’t be on a more exciting timeline.
- jacquesm 3y agoBut that first contact point transistor, even if it degraded rapidly actually worked, the challenges were to package it properly and to make it smaller and more reliable. This stuff, assuming it is all true is more at the level of the first inkling that semiconductor diodes might be a thing. We still have to reach that transistor stage (which would mean we an expensive way to manufacture a small stretch of usable conductor, say a few cm). Then you can start thinking about high volume production in any desired length and commercialization. So from a strict materials science point of view there is still a ton of work to be done even if everything so far turns out to be true. There is a good chance that even if the material isn't superconducting in bulk small regions of it are (the chances of that are actually higher than that it is all superconducting) and there is still a good chance that they are simply mistaken. But even if it is just superconducting grains smaller than a millimeter that would already be a massive discovery.
- regularfry 3y agoIf it has superconducting grains but isn't superconducting in bulk, is it likely that those grains could be separated, oriented, and combined to make a bulk superconductor? Because I can guess how you'd go about doing the first bit: crush it, put a magnet under it, and scrape off any bits that float...
- wiz21c 3y agoDumb question: why all the fuss ? I have checked a bit on the web but I fail to grasp the practical consequences of it (I mean if LK99 is the thing)). Could someone explain what could be done with that material ? For example, if we can transport electricity with a super conductor over long dsitances (1000 of kms), then what happens ? Is it just an incremental progress or is it a huge breakthrough ? (I am not much trained in physics)
- jacquesm 3y agoThis has been covered in every thread about this stuff so far, maybe read those other threads first and then be more specific?
- wiz21c 3y agoI admit I didn't read all the threads in detail. I'll give it another try :-)
- MayeulC 3y agoEspecially the first two threads (I think those have the highest scores for "superconductor" on HN).
- jacquesm 3y agoHN has a search function (bottom of the page, not ideal but the search itself works quite well), type in superconductor, then select order by date. That will give you the stories as posted in reverse order. Or click here: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&query=superconductor&sort=byDate&type=story https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
- 0xB31B1B 3y agoHuge breakthrough. Energy efficiency is just one gain. This also potentially unlocks major gains in quantum computing, fusion energy, tradition computer chip design allowing another 30 years of moore’s law, batteries with zero energy loss leading to ultra dense batteries and electric aviation
- radioactivist 3y agoA few comments. 1) This is simulation result using density functional theory. While a standard method for understanding the electronic structure of materials it often does not do so accurately when correlations (electronic interactions) are strong. In this kind of context (where strong interactions are expected to be necessary to give something like high temperature superconductivity) what one is looking for from a DFT simulation is an indication of what kind of starting point to extend further and include interactions. 2) What is seen here are features called "flat bands". Essentially, the kinetic energy of the electrons relevant at low energies is only weakly dependent on the (crystal) momentum of the particle. Having lots of different states (different momenta) at similar energy usually means the interactions are more important than in materials where the kinetic energy is larger and more dispersive (depends more strongly on momentum). Here the partially filled d-shells of the Cu atoms appear to make a flat band at low energy. This flat band is partially filled and thus is potentially susceptible to interaction induced instabilities. 3) Flat bands can come from trivial features of a crystal as well. If you've got isolated atoms far apart enough that their atomic orbitals barely overlap their bands will be flat. Some of this may be at play here since the Cu atoms seem to be quite distant (7-9 Angstroms or so). 4) Flat bands appear in many many kinds of systems (at the level of DFT, even at the level of experiments, etc, etc) and do not necessarily imply superconductivity, let alone high temperature superconductivity. Even if the presence of flat bands is pointing towards stronger and more important interaction effects these interaction effects can stabilize other kinds of order instead (magnetism, charge order, etc). 5) Predicting what instability is realized is hard and can be quite delicate. There are materials where this can be debated (theoretically and sometimes experimentally) for years. Predicting the onset temperature of the order that is produced is hard. I.e. Don't necessarily expect a reliable estimate of the critical temperature from theory.
- jacquesm 3y ago> and do not necessarily imply superconductivity, let alone high temperature superconductivity That's true, but are there superconductors that do not have those flat bands? If not then it wouldn't be evidence that it is superconducting but it would at least check one more expected property (based on the evidence obtained about superconductors so far).
- carabiner 3y agoCMTC says this preprint changes nothing. https://twitter.com/condensed_the/status/1686373904044949504?s=46&t=N5oP9SrFuyxd0pRLixzkBQ https://twitter.com/condensed_the/status/1686373904044949504... A lot of other researchers close to this type of work have come out to say the same. Lots of materials are like that, simulation is still too approximate etc.
- Decabytes 3y agoSo what are some examples of benefits that a room temperature super conductor would allow?
- riformareov 3y agoThe mention of quantum neural networks, quantum data encodings, and quantum feature spaces raises my curiosity about the technical intricacies and practical implications of these concepts. It's evident that this work contributes to advancing the understanding and potential applications of quantum machine learning.