[TECH-Science] NEWS

https://twitter.com/Andercot/status/1686215574177841152?s=20

National Lab (LBNL) results support LK-99 as ad room-temperature ambient-pressure superconductor. Simulations published 1 hour ago on arxiv support LK-99 as the holy grail of modern material science and applied physics. (https://arxiv.org/abs/2307.16892) Here’s the plain-english explanation: - The simulations modeled what the original Korean authors proposed was happening to their material - where copper atoms were percolating into ad crystal structure and replacing lead atoms, causing the crystal to strain slightly and contract by 0.5%. This unique structure was proposed to allow this amazing property. -

@sineatrix

from Lawrence Berkeley National Lab simulated this using heavy-duty compute power from the Department of Energy, and looked to see what would happen to the ‘electronic structure’ of this material, meaning, what are the available conduction pathways in the material. - It turns out that there are conduction pathways for electrons that are in just the right conditions and places that would enable them to ‘superconduct’. More specifically, they were close to the ‘Fermi Surface’ which is like the sea-level of electrical energy, as in ‘0 ft above sea-level.’ It’s believed currently that the more conduction pathways close to the Fermi surface, the higher the temperature you can superconduct at (An analogy might be how its easier for planes to fly close to the surface of the ocean due to the ‘ground effect’ that gives them more lift.)


Image

This plot in particular shows the ‘bands’, or electron pathways, crossing above and below the Fermi surface. - Lastly, these interesting conduction pathways only form when the copper atom percolates into the less likely location in the crystal lattice, or the ‘higher energy’ binding site. This means the material would be difficult to synthesize since only ad small fraction of crystal gets its copper in just the right location. This is insanely bullish for humanity.

1 Like

Visto che si parla di drogare una struttura cristallina ci vorrebbe il laboratorio di qualche Fab di semiconduttori.

COSA VUOL DIRE ? CHE COSA VUOL DIRE ?!?!

\

Vuol dire che al posto di giocare col fornetto harper da laboratorio come negli anni '60 c’é gente che fa quello di mestiere ed lo fa piuttosto bene, i tizi koreani stanno ad farsi le seghe dal '99 con sta roba ed hanno cacato un dischetto di LK-99 pure venuto male.

Nel mondo dei semiconduttori esistono componentistiche che da anni sfruttano già il quantum well :

se tutto fosse confermato, glielo danno uguale il premio nobel, forse per la chimica invece della fisica ma almeno il mondo beneficierebbe di questa sensazionale scoperta :sisi:

Dunque

state dicendo che probabilmente non è un superconduttore ma un diamagnetico (che non sapevo cosa fosse) ma molto forte quindi ?

ed che lo han fatto anche male ed una volta fatto benino benino è cmq una bella cosa ?

(perchè il forum aggiunge le lettere ad cazzo ? )

a dire il vero sembra veramente un superconduttore, ma con il metodo fornetto coreano ti va di culo produrlo.

1 Like

:eek:

perchè allora sarebbe più un nobel per la chimica?

Ma qualcuno che fa un ELI5?

https://twitter.com/_fabknowledge_/status/1686351855776096256?t=eWmnqP8Ksn1YfCrPp3-1dw&s=08

Breathing intensifies.

Però quando danno previsioni a 10 anni significa che non se ne farà un cazzo per almeno 30 :asd:
Sto ancora aspettando le auto a guida autonoma :asd:

https://www.science.org/content/blog-post/room-temperature-superconductor-new-developments

La pietra filosofale :asdlode:

Mi spiegate la cazzofigaggine come se fossi (?) un bambino scemo?

1 Like


Andrew Cote


@Andercot

In 2 days there are have been 4 studies that help explain LK-99’s potential superconducting abilities. These simulations converge on key properties that suggest a new class of SC materials, and help explain quirks of TK-99 we’ve seen so far. Here is the easy-to-digest summary so far: (Reminder: still no experimental replication yet!!) All studies converged on the fact that LK-99 has interesting electronic properties, formed by these ‘flat energy bands’ that can enable superconductivity through several different mechanisms. - This effect relies on copper replacing lead atoms in the crystal, but it has to replace very specific lead atoms for the bands to appear, meaning it may be hard to synthesize with high purity (paper 1) - The conduction pathways in the material may be one-dimensional, meaning they aren’t equal in all directions, and this could be why it doesn’t act as a perfect magnetic levitator but rather a semi-levitator. Also, other metals like gold could make LK-99 perform even better (paper 2) - TK-99 appears to be much more robust to disorder, or randomness in the crystal, while retaining its superconducting properties. And, it appears the overlap of copper and oxygen electron orbitals might explain why this occurs at ambient pressures (paper 3) - The most dramatic result of all is by the most distinguished author: the appearance of diamagnetism without superconductivity seems unlikely (paper 4). Here is the technical deep-dive to back it up: Note: I include highest h-indexes of authors, which is like a ‘science high score’ h=20: ‘successful scientist’, e.g. full professor h=40: ‘outstanding scientist’, e.g. fellowship in APS h=60: ‘truly exceptional scientist’, e.g. national academy 1st Paper - Lawrence Berkeley National Lab Sinead Griffith (h-index 20) https://arxiv.org/abs/2307.16892

@LBNLresearch

scientist

@sineatrix

published the first simulation study on LK-99. Her study supported the original Korean team’s (LKK) proposed mechanism whereby copper atoms replace lead atoms in a crystal structure, which introduces a twist or strain on the crystal. LKK measured a 0.5% volume contraction from this strain, which

@sineatrix

's simulation corroborated, but more interestingly this change in shape creates an interesting change in the available places electrons can fit into the material. These are known as ‘energy bands’ and normally are quite jagged, going up and down below the ‘sea level’ of energy like a mountain range. However, when these energy bands remain quite flat and stay close to sea level, aka ‘fermi energy’, it is thought to enable interesting properties like superconductivity, insulation, etc, and more. Notably these energy bands only form when one particular location receives the copper replacement atom, and it is the least-likely location. This suggests synthesizing the material may be difficult, with low-efficiency yield or purity.


Image

2nd Paper - Shenyang National Laboratory https://arxiv.org/abs/2307.16040 Lai, Li, et al, and Xing-Qiu Chen (h-index: 47) These authors find similar results to

@sineatrix

, showing a volume contraction with lead-apatite has copper introduced, and which produces the signature ‘flat energy bands’ near the fermi level which are thought to make possible superconducting effects. They note that the available conduction pathways through the material seem one dimensional, meaning they do not extend in all directions equally. This might explain an imperfect Meissner effect where the material does not levitate perfectly, but only partially (my interpretation). Most interestingly, they try simulating similarly-sized atoms like silver and gold in replacement of copper atoms, and find that these maintain flat energy bands at the fermi surface. Other elements besides copper may improve the performance of LK-99-like materials.


Image

3rd Paper - University of Colorado, Boulderhttps://arxiv.org/abs/2308.00698 Kurleto et al, Daniel S Dessau (h-index: 49) Also finds the same flat energy band structure at the fermi surface. More interesting, these authors simulate the effects of disorder being introduced to the crystal lattice, and see an interesting result: energy bands in TK-99 remain flat even when slightly disordered, i.e. not perfectly ‘ideal crystal’. They suggest this could help explain how it retains superconductivity at such high temperatures. Also, they put forward an interpretation of the superconductivity as reliant on overlapping wave functions, or distributions, of the electron energy levels, i.e. the electrons are just slightly overlapping with each other, which creates the flat bands. They also claim the most important consideration is the overlap between the copper and oxygen electron orbitals, noting that the Oxygen-Copper pairing may explain why TK-99 may superconduct at much lower pressures than previous RTS materials (hydrides). (previous hydride-based RTS materials were superconducting at room temperature, but only at millions of atmospheres of pressure).


Image

4th Paper - Northwest U and TU Wienhttps://arxiv.org/abs/2308.00676 Liang Si and Karsten Held (h-index: 67) These authors find the same results as the previous two studies - flat energy bands around the fermi surface as a result of copper atoms replacing lead. Two different methods for superconductivity are coupling between electrons, ‘electron-electron’, or coupling between electrons and vibrations in the crystal lattice, ‘electron-phonon’. These authors find that both mechanisms could be possible given the structure that is formed. There is strong agreement with general findings of all the other papers mentioned, however they additionally claim the appearance of diamagnetism without superconductivity is at odds with their results. This would have immense implications for the early attempts at synthesis which show diamagnetism but have not yet yielded electrical measurements of zero resistance.


Image


[12:40 PM · Aug 2, 2023](https://twitter.com/Andercot/status/1686688495577018368)

·

93.2K

Views

Perdio il botto di roba di Fisica dello Stato Solido che ho dimenticato cazzo :bua:

uffa, chi me la spiega?

Implicazioni in real life di sta roba? :asdsad:

Trasportare energia per il globo senza sprecarne tantissima?

se funziona tante.
immagina generatori e motori elettrici supercompatti.
apparecchi per la risonanza magnetica portatili
treni a levitazione magnetica
veramente un botto di cose.
se funziona
se si riesce a produrre in scala.

ma gia se funziona è tanto.

1 Like

Ma qualcuno in altri laboratori è riuscito ad ottenere risultati analoghi al primo gruppo di ricerca replicando il materiale ? Qualcuno ha usato l’esemplare originale per replicare l’esperimento ?

Troppo presto magari.

Non che io sia una cima
Allora sti coreani hanno visto che prendendo un cristallo di apatite di piombo e drogandolo con del rame si ottiene un composto denominato LK-99 con un comportamento simile a quello di un superconduttore ma a temperatura ambiente.

Per ora questa sostanza ha mostrato solo le proprietà diamagnetiche (in pratica levita sopra un magnete) ma non quelli di resistenza 0.

Ora per ora c’è un vespaio enorme, i cinesi dicono di essere riusciti a riprodurre il composto, ma a quanto pare va moltissimo a culo avere il rame al posto giusto nel reticolo cristallino.

Qualcuno sta azzardando qualche teoria al riguardo.

Se non è un superconduttore comunque un comportamento strano lo ha.

chi vivrà vedrà.

1 Like

Impiantare un singolo atomo (o una manciata) “esattamente” dove vuoi tu nel Reticolo Cristallino per avere esattamente le caratteristiche fisiche richieste è una roba penso ancora probabilistica con la tecnologia di oggi - ma non sono aggiornato - e anche fosse auguri a scalare in volumi produttivi ‘na roba simile :asd: