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Comment by samhuk | Hacker News Reader

My ultimate take-away about LK-99 since the start has been that, even if it doesn't turn out to be a holy-grail or whatever, the novel ideas behind the material are incredibly interesting.

The idea of causing tiny (~0.5%) crystal lattice shrinkage with cuprate percolation is a really interesting idea.

So far, only huge pressures or very low temperatures (i.e. Physics) have been used to cause that shrinkage, therefore perhaps LK-99 could, at the least, mark the time that Physicists hold up their hands, admit that they have failed, and let the Chemists give it a shot.

I'm slightly oversimplifying the situation, of course, and the disciplines of science cannot be so distinctly separated, but, y'know.

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Physicists were by no means holding the chemists back. Condensed matter is full of chemists, it's the point at which the two subjects meet.

I’ve published in computational solid state. My doctorate is, on paper, in earth sciences (mineral sciences!) and you’re going to find all of the materials science department and a few engineers in the vicinity too. Solid-state is one of those five-way borders in the Benelux countries where everyone speaks three languages.

My MSE dept was also colocated with mining engineering. Evolved from the metallurgy dept of a past era. We seemed to have a foot in manufacturing, computational materials, theory and chem lab.

Is there an intuitive explanation of why shrinkage of a material is beneficial for superconductivity. Naive question, particles physicist by training.

When a material shrinks, it can create immense internal stresses equivalent to what it would experience at extreme pressures. Compare to say a Prince Rupert's drop.

This is how I explained LK-99 to a friend a couple days ago :P

That's very interesting! I remember a while ago I read about a room temperature superconductor... but it required enormous pressures.

I have a theory of superconductivity that also explains that, unfortunately this comment box is too small for me to explain it.

Condensed matter physics and materials chemistry certainly become inseparable in certain areas

Indeed. The separation between "Chemistry" and "Physics" completely breaks down when you start dealing with electron behaviours.

I've actually got a little tin-foil-hat pet theory that Chemistry is slowly dying as it approaches "completion" of its roots (macroscopic phenomena of matter), and is gradually being subsumed by Physics. To at least a silly layman like me, lots of bleeding-edge Chemistry nowadays reads like your average Physics, e.g. doing quantum simulations for protein folding, superconductors, etc.

I'm probably just being silly though, right?

Chemistry has a ton of unsolved problems that are almost unbounded. The big fun one is trying to create the complete graph network of useful chemical reactions so that we can find paths of higher efficiency when making certain molecules.

This compute hard problem will take the world’s chemist to collaborate on a large scale because they don’t have a great database built yet that can enable this.

Chemistry also covers nano/microscale. I'm not sure "macroscopic phenomena of matter" adequately describes it.

Computational chemistry tends to be done in collaboratiin between specialists, especially after grad school. You also have to confirm things - you can compute whatever you like, but there's no way to know if your simulation reflects reality without confirmation.

And in what way had physics has beaten chemistry in the case of LK99? They did a post-facto DFT calculation supporting the apparent results, which may or may not be real.

It seems like an illustration of why chemistry is as robust as ever.

The big software unification driving this has been chemists moving to the (post-)DFT methods the materials people had to use, even for some of their small molecule work. Oversimplifying wildly, a lot of small molecule chemistry is driven by medicine and they started caring a lot about, for example, ab-initio protein models…

As many other people have said, there is no physics or chemistry in solid-state materials; most universities will have multiple groups in this area across three to five different departments (physics, chemistry, materials science, materials engineering, earth sciences).

(The reason materials people were on DFT is that you need to simulate more atoms to model a material. Standard DFT methods scale as O(n^3) with system size, and there are linear-scaling methods like SIESTA and ONETEP; many computational chemistry methods like Configuration Interaction are much worse.)

You're not being silly at all. There is a joke about that:

Sociology < psychology < biology < chemistry < physics << math.

also in webcomic form: https://xkcd.com/435/

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