Lawrence Berkeley Lab Simulations Support Lk-99 Superconductor

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Lawrence Berkeley National Lab simulated this using heavy-duty compute power from the Department of Energy, and looked to see what would happen to the ‘electronic structure’ of this material, meaning, what are the available conduction pathways in the material. It turns out that there are conduction pathways for electrons that are in just the right conditions and places that would enable them to ‘superconduct’. More specifically, they were close to the ‘Fermi Surface’ which is like the sea-level of electrical energy, as in ‘0 ft above sea-level.’

Arxiv – Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite

Sinead M. Griffin1,2
1Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA and
2Molecular Foundry Division, Lawrence Berkeley National Laboratory, Berkeley, California, 94720, USA

– The simulations modeled what the original Korean authors proposed was happening to their material – where copper atoms were percolating into a crystal structure and replacing lead atoms, causing the crystal to strain slightly and contract by 0.5%. This unique structure was proposed to allow this amazing property.

– @sineatrix
from Lawrence Berkeley National Lab simulated this using heavy-duty compute power from the Department of Energy, and looked to see what would happen to the ‘electronic structure’ of this material, meaning, what are the available conduction pathways in the material.

– It turns out that there are conduction pathways for electrons that are in just the right conditions and places that would enable them to ‘superconduct’. More specifically, they were close to the ‘Fermi Surface’ which is like the sea-level of electrical energy, as in ‘0 ft above sea-level.’ It’s believed currently that the more conduction pathways close to the Fermi surface, the higher the temperature you can superconduct at (An analogy might be how its easier for planes to fly close to the surface of the ocean due to the ‘ground effect’ that gives them more lift.)

– Lastly, these interesting conduction pathways only form when the copper atom percolates into the less likely location in the crystal lattice, or the ‘higher energy’ binding site. This means the material would be difficult to synthesize since only a small fraction of crystal gets its copper in just the right location.

These theoretical results suggest that the apatite structure provides a unique framework for stabilizing highly localized Cu-d states that form a strongly correlated flat band at the Fermi level. The central role of stereochemically active 6s2 lone pairs of Pb(2) manifests in the formation of a chiral charge density wave and the propagation of structural distortions with connected polyhedra.

When Cu is substituted on a Pb(1) site, the result is a cascade of structural alterations, including reduced lattice parameters, changes in coordination, and modified polyhedral tilts, leading to a local Jahn-Teller distorted trigonal prism around Cu. This results in an unusually flat set of isolated dyz/dxz bands with half-filling. I briefly note that achieving such a crystal field environment should also be possible in intercalated twisted heterogeneous bilayers where selection of different heterobilayers can provide the mirror symmetry breaking, while moir´e twist can provide an arbitrary rotation of the upper and lower triangles. In fact such a platform would be ideal for probing the physics found here given its broad
range of tunability and the state-of-the-art characterization probes for their interrogation.

In this system, I have identified several potential sources of fluctuations that could contribute to pairing. Firstly, I identified a charge density wave (CDW) driven by chiral lone pair ordering on the Pb(2) sites – the presence of this CDW is strongly connected to the structural rearragement that occurs when Cu is incorporated into the Pb(1) lattice sites. In addition to this, I identified two zone-center phonon modes that trigger the global structural deformation that occurs as a result of the Cu substitution, suggesting potentially strong electron-phonon coupling for these modes. Finally, I calculated the relative exchange interactions between Cu in neighboring unit cells. Interestingly for the out-of-plane coupling, that is, along the Cu-Pb-Cu one-dimensional chains, I find ferromagnetic coupling is favored by 2 meV/Cu over antiferromagnet coupling, even though the Cu are over 7 ˚A apart, suggesting that spin fluctuations could also play a key role.

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 obtaining a bulk superconducting sample. 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.

Manifold prediction betting market odds have doubled with the Berkeley and Shenyang theory papers.

14 thoughts on “Lawrence Berkeley Lab Simulations Support Lk-99 Superconductor”

  1. Allow me to recommend vibrating the Lead/Copper, at various frequencies, during its amalgamation. I’ll go you halves in a Nobel Prize.

  3. So the materials parameter space has a theoretically identified gradient toward room temperature superconductivity which is compute-tractable, as just demonstrated by LBNL, and there hasn’t been an all-out effort to throw massive gradient descent ML at the problem?

    • We’re just getting started. All this stuff is still in pre-print, fresh out of the vacuum furnace. You can certainly expect a lot more research of various kinds into this in coming years.

  4. So when do I get my superconducting wheel motors/generator-brakes, that fully replace brake discs (and the traction motor) without even increasing the un-sprung weight?

    • Forget the re-gen braking! Mount a large (3’x6’) brake material sheet (x 1” thick) on the underside of the butt of your magnetically levitated vehicle then shut of the levitation field back there. Might make drifting a lot more spectacular, too!

  5. Superconductivity is great. But imagine if we did not have to transport electricity to buildings. And I have the solution. Now I know everyone will say “it’s impossible ” but much of our now every day life were also “impossible”.
    I developed a magnet motor that produces usable torque and RPM and can easily drive a generator or whatever you need.
    EVs will be cordless and buildings will be 100% off grid. It’s design is incredibly simple, cheap and has minimal moving parts for long service life with minimal maintenance.
    If anyone interested in helping to push us into a free and green sustainable energy production . Please feel free to contact me for further information.
    Intellect property protection is the biggest issue. These are literally so simple to build. Anyone can do it on their coffee table. That’s where I built my first design.

  6. Huazhong University of Science and Technology had success.

    “Under the guidance of Professor Haixin Chang, postdoctor Hao Wu and PhD student Li Yang from the School of Materials Science and Technology of Huazhong University of Science and Technology successfully for the first time verified the LK-99 crystal that can be magnetically levitated with larger levitated angle than Sukbae Lee‘s sample at room temperature. It is expected to realize the true potential of room temperature, non-contact superconducting magnetic levitation.

    https://www.bilibili.com/video/BV14p4y1V7kS/?share_source=copy_web&vd_source=4627c2a4ec79c14d7e37ed085714be96

  7. I haven’t been able to leave this anywhere else, but something for those of you that read this to consider: after around a century, the mechanism of how the lead-acid battery works was finally elucidated a few years ago, having to do with its unusual size and orbits. Some of lanthanides (and, presumably, actinides) have this property as well. I’ve had a feeling that if this pans out they’ll find out it’s a similar mechanism at play, though perhaps only during cooking.

    After reading this particular article, it gives me hope that, even if LK-99 is worthless, it will lead to something that WILL work much like early drug research started with substances that couldn’t be administered directly, but then derivatives were created with lesser or no side effects.

    We’ll know soon enough, assuming that the world governments don’t decide to classify what they find as national security (after all, this is about the biggest thing find that could happen in the 1st quarter of the 21st century short of global thermonuclear war.

  8. The key point being the Cu substitution not on the lowest Pb site, but the next higher site is gonna be important.

    • The next thing to try, I suppose, is to pre-dope it with something that ties up the lowest energy sites, so that the desired sites for the Cu substitution BECOME the new low energy sites.

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