Hacker News Reader

Comment by Tadpole9181 | Hacker News Reader

Building on previously reported local superconductivity in graphite, have provided much explanation to why this occurs, has been in review for over a year, no signs of trying to sell a product, and provides guidance for further material research...

> In the present work, we report the first unambiguous experimental evidence for the global zero-resistance state, RTSC, in the scotch-tape cleaved highly oriented pyrolytic graphite (HOPG) that possesses dense arrays of nearly parallel line defects (LD), the wrinkles...

> The basic principle we have uncovered is that linear defects in stacked materials host strong strain gradient fluctuations, which induce the local pairing of electrons into condensate droplets that form JJA-like structures in the planes.

Very neat!

View on HN

Care to translate it? It's a wall of lingo for me.

For now, this is very interesting, but it still does not exist any obvious path for using this effect in a practical device.

Because superconductivity is not a property of the normal structure of graphite, but it appears when a certain configuration of defects is formed by breaking the graphite, I assume that it is difficult to obtain twice the same properties.

Moreover, because superconductivity appears in a fragile crystal, it could not be used for flexible cables, but only for rigid PCBs or inside integrated circuits. Because the superconductivity is on the surface of the crystal, not in its volume, it will not be able to carry high currents.

Nevertheless, it is likely that after some years the reproducibility problems could be overcome.

Neither superconducting graphite nor lead apatite appear promising for high-power applications, but one of them or a similar material could lead to significant improvements in integrated circuits and PCBs.

This research seems predominantly focused on explaining the actual mechanism by which RTSC can be achieved, and a demonstration of it. Understanding the "why" is the best part, as it allows us to begin intentionally designing ways to force these wrinkle impurities onto not only this material, but others.

Compared to modern chip manufacturing processes, cleaving and stacking pyrolitic graphite in a controlled way seems quite doable. I'd like to be optimistic, at least!

A ceramic, relatively fragile superconductor can be powdered and embedded in a flexible material, like a polymer, and retain superconducting properties. You see this in use currently with relatively high temperature superconductors, where flexible cables are able to be produced. As long as you have unbroken chain of connections from end to end, in some material the orientation doesn't matter, you just need tiny little bits that are touching eachother sufficient to make an electrical path.

Other materials, like glass, oils, metals, liquids, can serve as an embedded substrate, which can then be encapsulated by a flexible surface material. LK-99, with as much lead content as it had, would be difficult in terms of consumer safety, but graphite is trivial. If you could produce a sufficient quantity of superconducting particles to embed in polymer, then insulate cord, tape, or other flexible form factors, you wouldn't have to worry to much about disposal and recycling. LK-99 would be a possible toxic addition and probably not great for the world, even with superconducting features, in a public commercial context.

I can try an ELI5: We have previously seen that a form of graphite with impurities demonstrates superconductive behaviors to some degree at very tiny, inconsistent scales. They came up with an idea on the physics of why this happens to this material and have managed to intentionally reproduce the effects at a larger scale where we can say this is a genuine property of the material and not a weird localized effect on a tiny fraction of it in certain conditions.

The best I can explain the actual physics would be that some interactions at the impurities cause electrons to form "wires" of superconductivity in one axis across them. This isn't unheard of in existing materials, but the problem is that in those materials they tend to be isolated "wires" and even tiny disturbances throw the whole thing off.

But that in this material, the way these impurities forms creates a mesh of these "wires" where charge/magnetism can jump. Subsequently, it's resistance to disturbances climbs dramatically, as alternative superconductive paths can be taken as any disturbance propogates through a given part of the material.

They now believe we can use this knowledge to intentionally construct even more materials with this behavior.

And because I never stop finding it hilarious... Part of the preparation of the material is repeatedly taking a piece of scotch tape to a thin strip of the graphite, removing the top layer to make it extra thin.

The parts of my comment that are not quotes are just reasons to not immediately dismiss it, like many other "keystone" technology discoveries.

The scotch tape bit is fun. You can apparently strip atom thick layers of things with scotch tape, and also generate x-rays with it.

https://www.technologyreview.com/2008/10/23/217918/x-rays-ma...

Isn't that also how Graphene is made?

Graphene is made in various ways, ranging from scotch tape (relatively large crystals), to ultrasonic dispersion of graphite in water and soap (tiny microscopic flakes) to vapor deposition for large films, and all sorts of other variations of those themes depending on what you want. Flakes are trivially produced and are starting to be used as additives for desirable structural, electrical, and chemical effects.

Graphene was initially created using scotch tape, however, and it remains a reliable and simple method of getting high quality graphene for lab experiments.

Reply on news.ycombinator.com