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Origin of correlated isolated flat bands in LK99

arxiv.org

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Re: Origin of correlated isolated flat bands in LK99

#51

Post by junofan »

jakeinspace wrote: post #40
losteric wrote: post #26

Earlier quoted context omitted.

Posting for Cunningham's law :) * Green energy suddenly becomes way more viable. Megaprojects in the most efficient sites can send energy long-distance and store it with effectively no loss, somewhat mitigating regional variations (especially if we have a high-trust world order where a united global grid is viable). (I read LK99 might have some limitations carrying lots of current but presumably other approaches woul…

Sorry, but how does one create a transistor from a superconductor? Maybe I’m missing something here.

I think Josephson junctions. Also maybe you could eliminate copper loss by using LK-99 interconnect layers.

Re: Origin of correlated isolated flat bands in LK99

#52

Post by [deleted] »

drones wrote: post #9

Even if LK99 isn't the real deal, god has it been an exciting 2 weeks. Though I know absolutely nothing about material science, I have enjoyed the sheer enthusiasm and optimism the scientific community has shown. I feel like I'm part of something unique and special, something which could have only been achieved by the medium of accessible mass communication. The excitement here is palpable. I feel fortunate to be par…

[deleted]

Re: Origin of correlated isolated flat bands in LK99

#53

Post by pengaru »

dcow wrote: post #42
pengaru wrote: post #37

Earlier quoted context omitted.

What the simulation is saying though is that it requires some luck, not all the arrangements result in the band structure.

I understand. I'm saying that it's not LK-99 as described, then. Rather, it's something else that needs a more precise specification.

Or it's lk-99 as described, 5% of the time... basically they need to tune the process to improve yields. I'm not sure if that means it wouldn't be LK-99 if that's all that's going on here.

/me skeptical either way

Re: Origin of correlated isolated flat bands in LK99

#54

Post by ruined »

bick_nyers wrote: post #18
tnecniv wrote: post #16

Earlier quoted context omitted.

And audio nerds everywhere are still lusting after germanium transistors to this day!

Could you explain why? Sounds intriguing.

musicians often use them to generate distortion, which is purely an electrical phenomenon. germanium components tend to filter high frequencies and don't clip as sharply as silicon, generating tonal effects that can't really be replicated.

but mostly, a lot of early guitar pedals used germanium components, and so they are associated with prestigious historic guitar players.

here's a video demonstration. silicon first, then halfway through they flip the switches and play the same circuit with germanium components.

https://www.youtube.com/watch?v=W3F8-EAxlXA

Re: Origin of correlated isolated flat bands in LK99

#55

Post by ssklash »

bick_nyers wrote: post #18
tnecniv wrote: post #16

Earlier quoted context omitted.

And audio nerds everywhere are still lusting after germanium transistors to this day!

Could you explain why? Sounds intriguing.

Ge transistors clip audio signals in a "smoother" way. A softer knee, its called.

Re: Origin of correlated isolated flat bands in LK99

#56

Post by jacquesm »

Ccecil wrote: post #48
bick_nyers wrote: post #18

Earlier quoted context omitted.

Could you explain why? Sounds intriguing.

My understanding is that it is due to the lower voltage drop across the base junction. Germanium is .3v vs Silicon .7v, so with germanium you get less "crossover distortion" when the input signal is crossing the 0 line. edit: I understand that typically this is biased out with diodes...but the matching is not perfect and it is easier to start with half the distortion.

Never mind that any half decent amp design biases the base voltage to make sure that you're not going to have that problem.

Re: Origin of correlated isolated flat bands in LK99

#57

Post by m463 »

ivalm wrote: post #43
bibabaloo wrote: post #30

Earlier quoted context omitted.

If this could be simulated, can you help me understand why we couldn't have used simulation to find promising SC materials to investigate further earlier? Are there just too many permutations to investigate? It seems to my own naive self that if LK99 is the real deal, we mostly just got lucky finding it.

You have to put in the structure and then it's expensive to do the calculation. The space of possible structures is extremely large. If you have candidates then you can run through them, but you can't just random search through trillions of trillions of candidates.

yet.

Re: Origin of correlated isolated flat bands in LK99

#58

Post by jacquesm »

m463 wrote: post #57
ivalm wrote: post #43

Earlier quoted context omitted.

You have to put in the structure and then it's expensive to do the calculation. The space of possible structures is extremely large. If you have candidates then you can run through them, but you can't just random search through trillions of trillions of candidates.

yet.

And then you have to synthesize your candidates to ensure that what you think will happen really happens.

Re: Origin of correlated isolated flat bands in LK99

#59

Post by semajian »

yellowcake0 wrote: post #24

There's a lot of optimism in this thread, but does DFT (or any theoretical model really) actually have much predictive value in quantum chemistry? I've always gotten the impression that in this field the proof is in the pudding.

There are so many bad DFT papers out there because it's cheap to do DFT compared to growing and measuring samples carefully. DFT is notoriously unreliable as a predictive tool in strongly correlated systems, though when electron correlations are small it works well. I mean, I want this to be true, but I put little stock in DFT that doesn't calculate observables. So yes, you're right.

Re: Origin of correlated isolated flat bands in LK99

#60

Post by dtx1 »

ruined wrote: post #54
bick_nyers wrote: post #18

Earlier quoted context omitted.

Could you explain why? Sounds intriguing.

musicians often use them to generate distortion, which is purely an electrical phenomenon. germanium components tend to filter high frequencies and don't clip as sharply as silicon, generating tonal effects that can't really be replicated. but mostly, a lot of early guitar pedals used germanium components, and so they are associated with prestigious historic guitar players. here's a video demonstration. silicon first…

> generating tonal effects that can't really be replicated.

Seems my headphones can replicate it judging from hearing the audio. Am I missing something?

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