Explainer Thread on LK99 Room Temperature Superconductors

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Twitter user @fodagut has an explainer tweet thread on LK99.

@fodagut says
LK-99 is quite likely a room-temperature superconductor, or if not it points the way towards building one. But LK-99 is not going to be as easy to synthesize as you have been told, and it’s going to be a long, long way to viable applications. Unless we cheat…

For Superconductivity you need a single delocalized electron state with a sufficiently large band gap separating the higher energy states that thermal motion alone is insufficient to move the electron between them. We can do this for low temp or high pressure.

Lead-apatite is not a metal, but rather a mineralized bundle of wires, each of which are exactly one atom wide. It is more like bone or rock.

The Nobel-worthy contribution from Lee and Kim: apatite as a mineral confines its metal atoms (calcium in bone, lead and copper in LK-99) to be in a linear chain, so it does not have the blowup of electron states that a 3D crystal structure would have.

By replacing every 8th lead atom with copper (a highly strained and unnatural configuration), the few electron states remaining become separated by high energy gaps. There exists just one delocalized electron state that electrons freely conduct through.

By substituting copper atoms for lead in specific locations, Lee and Kim strained the metallic bonds to separate these electron states (requiring higher energies to enter), and purportedly got the gap so wide that thermal motion at room temperature is insufficient to jump the gap.

Such a material would conduct electrons in a single direction along that mineralized conductive wire, without any resistive losses. A room temperature, ambient pressure superconductor.

Replacing Every 8th lead Atom with Copper is Hard

By using the right molar ratios and crystalizing at high temp you can ensure that the right number of copper atoms replace lead in the unit crystal, but there is no way to ensure with this method that the linear chain of conducting atoms is strictly alternating as required.

Full replication and fully characterized will be hard.

Developing mass production will be even harder.

One logical solution is chemical vapor deposition. This is a process already used in semiconductor fabs to create alternating layers of material. To do so with minerals in an oven, and with atomically precise alternating layers is not impossible. This is still hard.

OR synthesize the material by building up layers ion-by-ion by placing reactive feedstocks molecule by molecule with atomic precision. This is mechanosynthesis AKA machine-phase chemistry

6 thoughts on “Explainer Thread on LK99 Room Temperature Superconductors”

  1. “To recap, we’re talking about a anisotropic bone-like mineral that conducts electricity along a specific line, with the conducting metal atoms substituted to provide an electron energy gap larger than room temperature thermal motion. ”

    Wow, I think that my grandma could understand this explanation. Great.

  2. Iris mentioned possible elemental sulfur contamination being relevant, as construction grade phosphorus is contaminated with it.

  3. It looks like they’ll be using ALD (atomic layer deposition), a variant of CVD, to make these materials. These are processes for making thin films that are very difficult to scale up to bulk material production. If superconducting properties can be used to enhance semiconductor devices, then that becomes your application.

  4. Twitter is such a bad platform for conveyance of anything but a slogan or soundbite.

    I did manage to read that string of thirty three tweets yesterday, and kinda winced when the end was a business pitch. This is mechanosynthesis AKA machine-phase chemistry is a thing though…. God used nucleic acids and enzymes and jelly organelles to do it. To me, atomic manufacturing seems farther away than replicating paperclip machines and Dyson spheres.

    The rest of the LK99 articles seem to be getting too heady to comment on…

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