<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>akasakahakada</author><text>Not 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.&lt;p&gt;1. Computation cost is large. 1 compute task for a small scale ~100 atoms last about 3 days to 1 week on supercomputer.&lt;p&gt;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.&lt;p&gt;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.&lt;p&gt;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.</text><parent_chain><item><author>bibabaloo</author><text>If this could be simulated, can you help me understand why we couldn&amp;#x27;t have used simulation to find promising SC materials to investigate further earlier? Are there just too many permutations to investigate?&lt;p&gt;It seems to my own naive self that if LK99 is the real deal, we mostly just got lucky finding it.</text></item><item><author>raziel2701</author><text>Man, I&amp;#x27;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.&lt;p&gt;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.&lt;p&gt;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.&lt;p&gt;I am, by far, the most excited I&amp;#x27;ve ever been about this being a RT, ambient pressure superconductor.</text></item></parent_chain></comment><story><title>Origin of correlated isolated flat bands in LK99</title><url>https://arxiv.org/abs/2307.16892</url></story>
<instructions>Your goal is to analyze the following comment and estimate how highly it will be upvoted by the Hacker News community.</instructions><comment><author>tired_and_awake</author><text>DFT scales horribly so it&amp;#x27;s phenomenally expensive to run. You have to have some other mechanism for knowing the general atomic layout before entering the DFT realm.&lt;p&gt;Once you know the atomic positions you can then do little perturbation simulations to model phonon dispersions or ask electron density questions.</text><parent_chain><item><author>bibabaloo</author><text>If this could be simulated, can you help me understand why we couldn&amp;#x27;t have used simulation to find promising SC materials to investigate further earlier? Are there just too many permutations to investigate?&lt;p&gt;It seems to my own naive self that if LK99 is the real deal, we mostly just got lucky finding it.</text></item><item><author>raziel2701</author><text>Man, I&amp;#x27;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.&lt;p&gt;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.&lt;p&gt;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.&lt;p&gt;I am, by far, the most excited I&amp;#x27;ve ever been about this being a RT, ambient pressure superconductor.</text></item></parent_chain></comment><story><title>Origin of correlated isolated flat bands in LK99</title><url>https://arxiv.org/abs/2307.16892</url></story>