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Man, 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 t
by raziel2701 3y ago
Man, 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.
- m463 3y agoyet.
- jacquesm 3y agoAnd then you have to synthesize your candidates to ensure that what you think will happen really happens.
- KRAKRISMOTT 3y agoWhat are all the material science ML companies doing? This would be a perfect technology demo if they can find the target
- jacquesm 3y agohttps://www.mpg.de/20096180/artificial-intelligence-in-material-design https://www.mpg.de/20096180/artificial-intelligence-in-mater... They are doing this sort of thing (that's more of a research institute). The problem is that you are not looking for the compound but for the exact way to manufacture it assuming that the original sample really is superconducting.
- throwawaymaths 3y agoThe problem is that this stuff is severely nonlinear, and for the raw formula there are not that many degrees of freedom to try. If you get a structure, there is no guarantee it's stable, or accessible by our synthetic techniques. Obtaining the training data is also likely to be tricky.
- Hermitian909 3y agoI've worked on the CS side of new material discovery. The tricky thing is that you don't actually have that much data so ML is not even close to plug and play. If you want to get results you end up needing to pair ML with a lot of theory and some tricky algorithms to help narrow the search space and even then that space is huge. Progress is being made but I think we're still at least 5-10 years from CS providing a real inflection in materials discovery.
- doingtheiroming 3y agoThe positive view here is that we are 5-10 years from being able to search for materials computationally using AI. That would potentially be more valuable than a single RTS.
- tired_and_awake 3y agoDFT scales horribly so it's phenomenally expensive to run. You have to have some other mechanism for knowing the general atomic layout before entering the DFT realm. Once you know the atomic positions you can then do little perturbation simulations to model phonon dispersions or ask electron density questions.
- rpep 3y agoThere are linear scaling DFT codes but they’re not available under open source licensing, only a strange license: https://onetep.org/ https://onetep.org/
- marcosdumay 3y agoWhat the fuck? Linear scaling DFT is something way more impactful than room-temperature superconductors. What's next? "Hey, I've used my FTL spaceship to verify the material at those friendly alien's library"? The fact that there has been no Nobel prize and we didn't spend a week around the web arguing "yes, it works!", "no, didn't work for me", "yes, I verified it!" highly implies that the site is trying to say something different than what we are understanding.
- tired_and_awake 3y agoI'm not intimately familiar with it, just guessing this is some orbital free method that theyve refined. Nothing new, just another approximation that cant model some effects.
- justinclift 3y agoPoking around the website, it seems to be owned by Dassault Systems and available for commercial licensing as part of their "Biovia Material Studio" product. PDF flyer about it here: https://www.3ds.com/fileadmin/PRODUCTS-SERVICES/BIOVIA/PDF/biovia-material-studio-onetep.pdf https://www.3ds.com/fileadmin/PRODUCTS-SERVICES/BIOVIA/PDF/b...
- akasakahakada 3y agoNot an expert but it just happen that my lab is full of DFT folks so I heard a lot about those everyweek. As people above already answered the questions, I gonna talk some extras. 1. Computation cost is large. 1 compute task for a small scale ~100 atoms last about 3 days to 1 week on supercomputer. 2. Search space is hugh. For each composition you can have different atomic (or crystal) structure. And here we are talking doping which means introduce impurities into the molecule. Chemical characteristics differs depending on which atom you swap for the impurity. Sometimes you may want to try all places. 3. Depends on initial values. Sometimes the initial value is just bad that the result is totally unusable, then you have tweak a little bit and throw back to supercomputer. This cycle might happen few times for 1 specific formula and structure. 4. Not 100% accurate. Often the resulting numbers are off by a few % or more which is hugh, compare to experimental results. Reason is that the simulation is not full scale, approximation is here and there to reduce computational cost.
- fpordeig 3y agoThis looks similar to the protein folding problem. Maybe an AlphaFold-like approach could work?
- fock 3y agonot soo similar really, but yes, alphafold-style generative models could help find realistic structures for a specific composition. However a) data is much worse (I would say so at least...), b) the clever tricks of alphafold centered around strings of aminoacid don't really apply to particles in a box... and c) search space might be even larger if you go to interestingly sized systems. Also there's been some people arguing about the particles in a box situation for a loooong time and the most promising approach currently is diffusion.
- akasakahakada 3y agoWe exactly considering this since this year. But there are some major problems that cannot be solved in short term. Inorganic crystal structure database (and there is one database literally this name) is way smaller than what we have for proteins. Also by nature, Transformer is hardly useful for crystals because the crystal is repetitive. You don't throw the same sequence over and over to transformer and hope it will work like magic. My current understanding is that Graph Neural Network is perfect for this job because graph can exactly describe this kind of repetitive nature of crystal.
- Sharlin 3y agoIt's like NP problems. It's much harder to find a solution than to check if a candidate solution is valid.
- marcosdumay 3y agoYes, the permutations are endless, and verifying each one is a bit expensive (up to extremely expensive, depending on the complexity of the material).
- foobiekr 3y agoBecause it's too hard. People vastly over-estimate what we can simulate at any level of fidelity with any scale below purpose-built stuff running on supercomputers..
- currymj 3y agocheaper alternatives to DFT (using ML especially) for this purpose is an active research area
- dcow 3y agoIt doesn't reproduce: https://arxiv.org/abs/2307.16802 https://arxiv.org/abs/2307.16802. That doesn't mean there's not something to further investigate, but LK-99, at least as described in the paper, is not it.
- pengaru 3y agoWhat the simulation is saying though is that it requires some luck, not all the arrangements result in the band structure.
- dcow 3y agoI understand. I'm saying that it's not LK-99 as described, then. Rather, it's something else that needs a more precise specification.
- pengaru 3y agoOr it's lk-99 as described, 5% of the time... basically they need to tune the process to improve yields. I'm not sure if that means it wouldn't be LK-99 if that's all that's going on here. /me skeptical either way
- xbmcuser 3y agoAh no they called the working prototype LK-99 so if it works it is if it does not then it is not. Instead of what you are saying that it works so is not LK-99.
- jacquesm 3y agoIt doesn't reproduce in that case, which is a useful data point but may not be the final word. The article linked in this thread suggests why making it may not be all that easy.
- dcow 3y agoI'm just saying that it's not really LK-99, then. It's something else that needs to be specified more precisely.
- pengaru 3y agoDisclaimer: this is not my area of expertise in the slightest. If we have the ability to computationally determine these things without any experimental data needed, and we know we're looking for a specific band structure, wouldn't we just do an automated search of possible chemistries to find everything producing said band structure? Then just whittle down that list to the easiest to produce and most common materials for the first to test... what am I missing?
- enraged_camel 3y ago>> If we have the ability to computationally determine these things without any experimental data needed, and we know we're looking for a specific band structure, wouldn't we just do an automated search of possible chemistries to find everything producing said band structure? Isn't this a plot point in that one Star Trek movie (episode?) where they go back in time and program a current-day computer to do this? edit: OK, I misremembered. Was thinking of this: https://www.youtube.com/watch?v=LkqiDu1BQXY https://www.youtube.com/watch?v=LkqiDu1BQXY
- jacquesm 3y agoThe parameter space for such a search even with a limited number candidate materials is immense. You'd need to guide the search somehow, that band structure might be the one, or it may not be... and every candidate that you flag will have to be synthesized which may not be all that easy.
- 7373737373 3y agoSounds like a good challenge for (Open)AI
- elfbargpt 3y agoDoes anyone know if there's a way to ensure those "particular Cu substitutions" happen at the correct atomic sites? Or I guess what's the way forward in terms of synthesizing
- jychang 3y agoIf you figure out how to ensure it gets dropped at the higher energy subsitution site, you would get a nobel prize as well.
- weard_beard 3y agoAnd another one if you determine whether copper is the optimal bond (as opposed to gold et al)
- j45 3y agoI’m not an expert in anyway but when I see detailed chemical compositions in an arxiv summary, a patents, and multiple publications, it’s almost like it’s ready to smile at all the scrutiny.
- konschubert 3y agoI’m reminded how after every LHC result, a million theoretical papers come out that are able to provide a theory which explains it. Is the solid state theory space similarly underdefined that you can find a theory for every result? Or is this paper significant?