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Electronic Structure of LK-99

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Re: Electronic Structure of LK-99

#91

Post by sheepscreek »

refulgentis wrote: post #45
sheepscreek wrote: post #42

Earlier quoted context omitted.

On a related note: I am deeply disappointed by how OpenAI has managed to continually dumb down ChatGPT. I’m sure the shortage of NVIDIA H100s and the demand for their APIs shooting through the roof has something to do with it. Perhaps they’ve switched to a quantized model? Who knows. And yes, LLaMA 2 is awesome. Progress is being made. But it’s slowed down. The novelty’s worn off. Now we’re lacking some fundamental p…

It's not dumber. You can verify this on their models with any prompt you ran at 0.0 when it first came out, I did. It's the exact same model run the same exact way. They've repeatedly confirmed this.

They confirmed the API still ran the same base model. But there was no mention of ChatGPT the service. I was referring to the latter above.

Re: Electronic Structure of LK-99

#92

Post by eco »

JKCalhoun wrote: post #81
SamPatt wrote: post #23

Earlier quoted context omitted.

Thanks for your input. What would you need to see to say "I am 100% convinced this is / isn't real"? And how long would you expect it will be before that occurs?

Waiting for Applied Science (the YouTuber) to make some in his lab.

I think he might be working on it. On Twitter he teased a homemade device for making very fine powder for, say, superconductors.

Here's his video of making YBCO for anyone that hasn't seen it: https://www.youtube.com/watch?v=sLFaa6RPJIU

Re: Electronic Structure of LK-99

#93

Post by bluecoconut »

jpmattia wrote: post #69
bluecoconut wrote: post #12

I got my PhD studying band structure of high-tc superconductors (experimentalist, ARPES). These Cu d-d interactions right at the fermi energy give me huge hope. Feels very familiar to other superconductors (re: all the cuprates). (Note: I specifically worked in a lab that was measuring a lot of the d-wave character / gap-energies of various superconductors) All in all, I'm now much more bullish on LK-99 being real su…

> These Cu d-d interactions right at the fermi energy give me huge hope. Feels very familiar to other superconductors (re: all the cuprates). As someone who is versed in semiconductor band structures but not superconductor band structures: What is it about Cu d-d interactions that causes the superconductivity? Degenerate energies in semiconductors don't give rise to electron pairing, so I'm a bit out to sea with the…

To be honest, this is a hunch thing more than a I can teach and explain it thing. To me it's just "a lot of the same stories" that are told about cuprates, and less of a "I can explain the mechanism".

Roughly, one of the "properties" that shows up with these materials is that the 3d orbitals of coper atoms are involved in forming the bands near the fermi level. Couple that with the fun story of Cu electron configuration being [Ar] 3d^10 4s^1, which suggests that spin-effects are "at play" with these electrons near their filling levels. Combine that with the spin-character properties of cuprate paring (eg. s-wave vs. d-wave superconductors, (d-wave for BSCCO for instance)). All together it lends itself to a nice spin-orbit coupled band "setup" at the fermi energy that I have a hunch somehow backs the underlying mechanism of these d-wave superconductors. Fully admit, there's some leaps there in the raw logic -- if I could fully explain it I probably would still be in the field, haha.

I'll note: I've been out of the field for ~8 years, but a quick google search led to some more recent papers [1][2] working through plausible explanations based on some of these copper d orbital shenanigans.

[1] https://www.scirp.org/journal/paperinformation.aspx?paperid=... [2] https://arxiv.org/abs/2105.11664 (d-p, but includes the Cu d-orbital and also specifically states "We also show that the effect of the nearest-neighbor d-d Coulomb interaction Vdd is actually quite important for the stability of superconductivity and phase competition.")

Re: Electronic Structure of LK-99

#94

Post by dudeinjapan »

qiqitori wrote: post #89

The material containing lead is very unfortunate. I have no doubts that (if it indeed turns out to be a superconductor) humans will use it anyway in any context where it provides even a slight benefit (cf. just in the lead department: leaded gasoline, leaded solder, etc.).

Once room temp superconductivity is shown to be possible, I bet we’ll find non-lead materials that can do it too.

Re: Electronic Structure of LK-99

#95

Post by swalsh »

jeffbee wrote: post #16

The most interesting phenomenon revealed so far is that the room-temperature superconductor people and the generative-LLMs-are-God people draw on the same limited global pool of credulity, such that HN cannot be flooded with both ChatGPT worship and superconductor speculation at the same time.

It's so hard not to be crazy excited about the future. The past few months are proving to be an absolute breakout for the literal human race.

So far we've seen:

1. in Dec 2022 We saw a fusion breakthrough seeing a net gain in energy

2. In March GPT-4 was released, which seems to be a seminal breakthrough in AI, and maybe of our first glimpse in what could become an AGI.

3. In May we find out apparently our government has recovered alien technologies

4. Then in July room temp super conductors just drop

Like this is the most insane period of time. Maybe the fusion technology doesn't scale, maybe GPT-5 doesn't scale, maybe the UAP thing was all a psyop, or a lie, maybe LK-99 doesn't turn out. But there's so much to hope for!

Re: Electronic Structure of LK-99

#96

Post by ayakang31415 »

dekhn wrote: post #71
ayakang31415 wrote: post #63

Earlier quoted context omitted.

If you run a bunch of simulations to brute-force-find what you're looking for, you run into a problem of infinitely many things to simulate. It is better to use domain knowledge to eliminate things that don't work and narrow down things that would have high chance of working in theory to give some sort of directional guidance for your research.

That domain knowledge wouldn't have suggested exploring this space for superconductivity. Turn the material science problem around: instead of looking for a substance that has a specific property, look at many substances until small amounts of any interesting property (young's modulus, etc) show up. By looking for "anything interesting" you are more likely to find something of interesting (ideally, several somethings…

I think the first insight to pursue LK-99 by the researchers was from the deceased scholar from their graduate school (department chair I believe?). The material was already found in 1999, but they need to try different synthesis methods over 1,000 times for slightly different chemical compositions. I am not sure if there are simulation methods to do that, but it was definitely theoretical insight that first convinced their teacher to start, and the work made the pupils to believe in what they are pursing as far as apparent background stories are concerned.

Re: Electronic Structure of LK-99

#98

Post by dylan604 »

dogcomplex wrote: post #88
dylan604 wrote: post #78

Earlier quoted context omitted.

You think all of the news about crypto fraud might have a chilling effect on the excitation?

lol same as it ever was

not really. before, fraud claims were from the non-believers. now, the fraud claims are from the SEC and other government agencies. one can be swatted away with clever tweets, er, xes (what are tweets called now?), the other sees people going to jail.

Re: Electronic Structure of LK-99

#99

Post by cthalupa »

boppo1 wrote: post #90
cantrevealname wrote: post #41

Earlier quoted context omitted.

The next breakthrough we need is with fusion technology. With unlimited fusion energy, room temperature superconductivity, and (soon) artificial general intelligence, the singularity won't be long off.

What fusion breakthrough is needed that isn't superconductors?

It's one of the biggest ones.

My understanding is that there are still some others that need to be figured out, like "The physical structure holding the thing getting the everloving shit bombarded out of it by high energy neutrons and causing it to degrade and fail over time"

Re: Electronic Structure of LK-99

#100

Post by semajian »

tnecniv wrote: post #85
carabiner wrote: post #64

More DFT? Haven't we concluded that has little predictive power?

I’d be interested in seeing a source on that. My understanding was that it was a powerful and popular computational tool. The theory is approximate but approximate theories can still be quite useful if the approximation is a good one.

It's basically an open secret, no one really believes DFT has much predictive power in strongly correlated systems (where relevant electrons cannot be treated as independent). It's not useless, but DFT calculations require many arbitrary choices and are hardly "first principles" in a meaningful way.
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