Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite · HackerPapers discussions

Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by rsfern

Mon, 07 Aug 2023 10:07:39 GMT

Two reports have increased my patience factor a lot on this First, a theoretical study found that the phase that’s reported to be superconducting is likely to be metastable based on some density functional theory calculations. That implies that actually making it may be rather difficult, and raises the bar for reproductions to show exactly what they are finding is superconducting or not. https://arxiv.org/abs/2307.16892 The second study was a comparison of the properties of superconducting Pb thin films with some of the data people have been reporting on LK-99 repro attempts. The authors…

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by httpz

Fri, 04 Aug 2023 08:37:46 GMT

>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... 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…

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by trafficante

Wed, 02 Aug 2023 22:45:15 GMT

> purity as in the sample is uniformly constructed of the right atoms but they are not in the right configuration The conclusions in the linked pdf suggest this may be the issue with LK99. 1. https://arxiv.org/abs/2307.16892

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by trafficante

Wed, 02 Aug 2023 22:11:38 GMT

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…

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by westurner

Wed, 02 Aug 2023 01:46:44 GMT

"Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite" (2023) https://arxiv.org/abs/2307.16892 : > Abstract: A recent report of room temperature superconductivity at ambient pressure in Cu-substituted apatite (`LK99') has invigorated interest in the understanding of what materials and mechanisms can allow for high-temperature superconductivity. Here I perform density functional theory calculations on Cu-substituted lead phosphate apatite, identifying correlated isolated flat bands at the Fermi level, a common signature of high transition temperatures in…

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by zeronullempty

Wed, 02 Aug 2023 01:16:12 GMT

More specifically they agree with another similar paper from Stanford's Sinead Griffin https://arxiv.org/abs/2307.16892

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — HN submission

Tue, 01 Aug 2023 18:53:54 GMT

Plausible theoretical foundation for LK99 RTAPS calculated via supercomputer

17 points; 3 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by throwaway23354

Tue, 01 Aug 2023 18:46:56 GMT

While you're correct about the scarce and sketchy evidence currently it is in the process of narrowing down. Or to put it better the evidence is mounting that it might be a breakthrough. It likely hard to manufacture correctly, but simulations done at Berkeley Labs seem to support the claims of the original paper https://arxiv.org/abs/2307.16892 And aside from that to be honest I hope that we have time to prove or disprove those claims, before any major news outlet jumps onto the hype train and ruins it.

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by redm

Tue, 01 Aug 2023 14:05:16 GMT

Seems there is new support that its legit! https://twitter.com/Andercot/status/1686215574177841152 National Lab (LBNL) results support LK-99 as a room-temperature ambient-pressure superconductor. Simulations published 1 hour ago on arxiv support LK-99 as the holy grail of modern material science and applied physics. https://arxiv.org/abs/2307.16892

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by jboggan

Tue, 01 Aug 2023 11:34:34 GMT

Preprint by Griffin from Livermore Labs gives a theoretical explanation of LK-99's superconductivity and also explains why labs are having a hard time synthesizing it. There are two Pb sites in the crystal structure that Cu can substitute at, the lower energy one does nothing but it's the higher energy site that creates superconductivity. https://arxiv.org/pdf/2307.16892.pdf "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…

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by jboggan

Tue, 01 Aug 2023 11:30:11 GMT

I think this theoretical result by Griffin at the Livermore Lab explains why labs are having difficulty replicating the LK-99 sample: https://arxiv.org/pdf/2307.16892.pdf There are basically two repeating crystal cells. Her theoretical calculation shows superconducting properties when you substitute one cell for copper, but not the other. The "bad" substitution is a lower energy substitution that occurs more easily. "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…

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by joefigura

Tue, 01 Aug 2023 06:43:27 GMT

I just wrote a comment in another thread that's relevant here too. It looks like the first superconductor paper was released by a rouge researcher, without the agreement of the other two authors or the rest of the LK-99 group. This forced the LK-99 group to rush to publish the official paper, with a cost to quality. The LK-99 group released v2 a week later (on Saturday), and probably will continue to update it. A premature release explains many of the oddities about the two papers The first paper submitted is titled "The First Room-Temperature Ambient-Pressure Superconductor." It lists three…

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by tatrajim

Tue, 01 Aug 2023 04:25:01 GMT

They're talking about a newer paper that provides some reason for optimism. https://arxiv.org/abs/2307.16892

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Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — HN submission

Tue, 01 Aug 2023 03:02:36 GMT

Origin of correlated isolated flat bands in LK99

397 points; 203 discussion replies on HN. Paper and source history. A submission is not an endorsement.

Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite — mentioned by carabiner

Tue, 01 Aug 2023 02:28:47 GMT

Research out of Berkeley, 1 Aug 2023: theoretical analysis suggests high-Tc superconductors from apatite possible, points to synthesis challenges. > 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…

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