Room Temperature, Ambient Pressure Superconductivity—This Time for Real?

[johnwalker]

Derek Lowe has posted an initial assessment of the superconductor paper in his Science column, “In the Pipeline”, “Breaking Superconductor News”, on 2023-07-26.

I wrote recently about the turmoil in the field of higher-temperature superconductors, but little did I know what was coming. Yesterday two preprints appeared on the rXiv site, the first bearing the attention-getting title “The First Room-Temperature Ambient-Pressure Superconductor”, and the second going into more detail about its behavior. As you’d imagine, this made something of a splash during the day on Tuesday!

Let’s look at what’s being claimed, and how strong the evidence seems to be. The authors describe a lead-based copper-doped material, LK-99, which is made by first preparing a well-characterized mineral (lanarkite, Pb2(SO4)O) from lead oxide and lead sulfate. Separately, copper phosphide (Cu3P), another well-characterized compound, is also freshly prepared from elemental copper and phosphorus. These two substances are ground together in a 1:1 ratio and the mixture is sealed in a vacuum-evacuated quartz tube and heated to 925C, forming LK-99, which is Pb10-xCux(PO4)6O, a dark polycrystalline material. The structure is very similar to lead apatite, a well-characterized phosphate mineral, but its crystallographic unit cell is slightly smaller due to the substitution of particular lead atoms in its lattice by copper ones.

And it’s this effect on the compound’s structure, the authors believe, that leads to its extraordinary superconducting behavior. Honestly, “extraordinary” doesn’t get it across. We’ve been getting excited over the years about superconducting materials that don’t even quite have to be cooled with liquid nitrogen, and this stuff is claimed to superconduct all the way up to room temperature and indeed up past the boiling point of water. Its critical temperature is said to be 127C (!) The phrase “boiling-water superconductor” is not one that I had ever used until yesterday, trust me on that.

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Another welcome feature is that their procedure for preparing LK-99 seems quite straightforward. You can bet that furnaces in solid-state materials labs around the world have been cooking yesterday and today to try to reproduce its synthesis and the properties, and we should be hearing about the results of these experiments very soon. The first samples should be coming out of the quartz vessels. . .sometime tomorrow, perhaps? Depends on what was available around the lab! Now, as the world knows, all such claims to date have fallen apart on closer inspection - indeed, the superconductivity research group at Rochester that I wrote about earlier this month is now about to have another paper retracted on suspicions of data fabrication. But those reports were on materials that take very specialized equipment to make and evaluate - this new report looks like it’s either going to fall apart very quickly or be quickly vindicated (as were the 1987 superconductor discoveries). I absolutely cannot wait to find out.

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But as usual, it’s a gigantic step to just show that such things can exist. That’s what will shake everyone up well before any applications come along, and if this reproduces, labs around the world will frantically start looking for quantum-well superconducting materials of their own. Who knows what could come out of that? Robust high-current-density room-temperature superconductors are right out of science fiction (SF readers will recall that one such material was a big plot point in Larry Niven’s Ringworld). Electrical generation and transmission, antennas, power storage, magnet applications (including things like fusion power plants), electric motors and basically everything that runs on electricity would be affected. We could stop throwing away so much generated power on heating up the wires that deliver it, for starters.

[johnwalker]

Superconducting magnet engineer Andrew Cote gives his view of the claim of room-temperature superconductivity in a Twitter thread collected as “Exploring the Possibilities of Room-Temperature Superconductivity: The Good, The Bad, and The Ugly”. Clips from the collection:

Summary
The good: There’s some plausibility here, and if so, it’s game-changing
The bad: Reasonable chance this is a similar but different physical property
The ugly: Their plots, and engineering usefulness

Let me explain:

The Good:
Lee-Kim-Kwon (LKK) use familiar materials, Cuprates, and measures some key metrics of a room-temp superconductivity (SC):

• Zero-resistivity
• Critical current
• Critical magnetic field
• Meissner effect

The bad:
Normally the superconducting transition temperature is predicted by measuring heat capacity versus temperature. This is the Debye Temp.

TKK say they can’t measure this, because the usual theories of SC don’t explain their sample: a lil bit sus

The ugly:
Some of their plots.

The net-net:
No champagne yet, but watch closely - this would be a serious game changer in things like power transmission, energy storage, and future-tech like quantum computers, fusion energy, mag-lev trains.

I’m even more optimistic than 6 weeks ago

Read the whole thing.

[CTLaw]

Will the LK-99 room temp, ambient pressure superconductivity pre-print...

[johnwalker]

Note that Manifold is (from their “About” page):

Manifold is a play-money prediction market platform where you can bet on anything.

⋮

• Mana (Ṁ) is the play-money used by to bet on our platform.
• All users start with Ṁ500 for free and can earn more by winning bets and gaining free bonuses.
• Most of our users never spend real money!
• It cannot be converted to cash, but can be redeemed for real charity donations at a rate of Ṁ100 to $1.

Thus, people betting are not actually backing their bet with money, so this is more like “putting your mouth where your mouth is”.

[CTLaw]

Any better?
https://polymarket.com/event/is-the-room-temp-superconductor-real

[johnwalker]

@CTLaw

Any better?

Well, on Polymarket they’re betting the USDC “stablecoin”, which must be bought for US$ (or else by exchange of other cryptocurrencies at the current market price) and is supposed to be redeemable for US$ if you go through the hoops to setting up an exchange account, link to a bank account, and all of the “know your customer” folderol required. So, to the extent that a tethercoin is real and retains its 1:1 peg to the US$, people are betting real money. This is presumably a way to get around the U.S. federal and state bans on “online gambling”, which define real-currency prediction markets within their prohibition. The only two prediction markets currently open to U.S. nationals are the university-operated PredictIt (based on New Zealand) and Iowa Electronic Markets, in…you guessed it…the U.S. state of Iowa. Neither, at this writing (2023-07-27 at 22:40 UTC), appear to have markets on replication of the claimed room-temperature superconductor.

Requiring participants in a prediction market to first get into cryptocurrency is going to dramatically reduce the breadth of participation and the liquidity of the market and its efficiency in establishing the probability of the prediction from the crowd. I would also doubt that operating a prediction market in the U.S. in a stablecoin is going to evade attacks against it as online gambling once its size grows sufficiently large to come onto the radar of state and federal “no fun of any kind” agencies.

[johnwalker]

Here is Anton Petrov’s summary of the situation regarding the room-temperature superconductor claims and the reasons for scepticism due to previous claims by other researchers in Nature, one retracted and the other increasingly dubious. Sadly, Petrov seems to be falling into the YouTube hole of “over-production”, littering his video with stock video clips that have nothing whatsoever to do with the subject matter bring presented.

If LK-99 Superconductor Is Real, It's a Nobel Prize! But Here's the Truth

[dbrow1]

There’s some consensus that the results can be questioned based on:

• Lenz’s law applying to copper (Lenz's law - Wikipedia)
• Copper phosphide (“Lanarkite and Cu3P were uniformly mixed in a molar ratio of 1:1 in an agate mortar with a pestle”). Pretty high copper content.
• No Meissner effect just standard copper-related phenomena based on Lenz’s law.

Not a good start if true!

[johnwalker]

Jack Sarfatti (@jacksarfatti) passes on the following message from Julien Geffray:

Date: July 29, 2023 at 5:25:03 AM PDT

There is a much more compelling, third paper on the LK-99 superconductor by the same authors. In fact this is a prior paper, published in a peer-review journal in April 2023, that nobody saw until now because it is written in Korean:

Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)
Volume 33 Issue 2   Pages. 61–70, 2023
1225–1429 (pISSN), 2234–5078(eISSN)
The Korea Association of Crystal Growth (한국결정성장학회)

Here is a link to the paper in Korean.
This is a machine translation of the paper by Google.

The following is the abstract of the paper, Google machine translated into (somewhat fractured) English. The paper is dated as having been accepted by the journal on 2023-04-18.

Abstract
This paper examines the way of thinking and limitations of physicists regarding the phenomenon of superconductivity and outlines how room-temperature and ambient-pressure superconductors can be developed through the statistical thermodynamic background of the liquid state theory. In hypothesis, the number of electron states should be limited by confining them to a state close to one-Dimension. Simultaneously, the electron-electron interactions should be frequent enough for the electrons to have liquid-like properties. As an example of implementing the hypothesis, our team reports the development of room-temperature and ambient-pressure superconductivity of a material named LK-99 (superconducting compound name developed in the research), whose structure was revealed through numerous experiments with a clue found by chance. Moreover, we summarize the theoretical and experimental basis for the characteristics and discovery of the world’s first superconducting material surpassing the critical temperature of 97° C at atmospheric pressure.

This paper includes descriptions of experimental tests and results which were not in the two papers cited in the main post, for example:

[CTLaw]

@johnwalker

Here is a link to the paper in Korean.
This is a machine translation of the paper by Google.

The following is the abstract of the paper, Google machine translated into (somewhat fractured) English. The paper is dated as having been accepted by the journal on 2023-04-18.

This March/April paper paper lists three more authors:
Lee Seok-Bae, Kim Ji- Hoon, Lim Seong-Yeon, An Su-Min, Kwon Young-Wan, Oh Geun-Ho

in addition to the three of the July paper:
Sukbae Lee, Ji-Hoon Kim, Young-Wan Kwon

[CTLaw]

A 1400+ hit patent search for:

(superconductor or superconductivity or superconducting) and (“room temperature” or ambient) in the title or abstract

Substantial reduction limiting to title:

(superconductor or superconductivity or superconducting) and (“room temperature” or ambient) in the title only

[johnwalker]

This is turning into a full-tilt, king-hell soap opera.

2023-07-28

2023-07-29

(“SBF” presumably refers to cryptocurrency con man Sam Bankman-Fried.)

Stay tuned for the gripping next episode!

[johnwalker]

On 2023-07-30, Alex Volkov, Andrew McCalip, and Ate-a-Pi, who have been prominent in the discussion of LK-99 on Twitter, hosted a Twitter Spaces conversation of more than two hours about the status of the claims, efforts to replicate the experiments, and sources of equipment and material. The conversation actually starts at the 2:40 mark after the elevator music.

Because X/Twitter operates as a data silo, it is not possible to embed the audio recording here. What you have to do to listen is to click on the screen shot below in a browser from which you are logged into X/Twitter, then click the Play button in the purple box, then wait until the player box appears at the right, which contains controls for the player. If you do not have an X/Twitter account, you cannot play the recording.

I have only listened to brief snippets of this recording so far and cannot speak for the quality of the information therein.

[johnwalker]

On 2023-07-29, we have a theoretical paper published on arXiv, “First-principles study on the electronic structure of {\rm Pb}_{10−x}{\rm Cu}_x({\rm PO}_4)_6{\rm O} (x=0, 1)” (full text at llink), by five authors from the Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, China, exploring the electronic structure of the reported LK-99 superconductor from first-principles calculations. Here is the abstract:

Recently, Lee et al. reported the experimental discovery of room-temperature ambient-pressure superconductivity in a Cu-doped lead-apatite (LK-99) (arXiv:2307.12008, arXiv:2307.12037). Remarkably, the superconductivity persists up to 400 K at ambient pressure. Despite strong experimental evidence, the electronic structure of LK-99 has not yet been studied. Here, we investigate the electronic structures of LK-99 and its parent compound using first-principles calculations, aiming to elucidate the doping effects of Cu. Our results reveal that the parent compound {\rm Pb}_{10}({\rm PO}_4)_6{\rm O} is an insulator, while Cu doping induces an insulator-metal transition and thus volume contraction. The band structures of LK-99 around the Fermi level are featured by a half-filled flat band and a fully-occupied flat band. These two flat bands arise from both the 2p orbitals of 1/4-occupied O atoms and the hybridization of the 3d orbitals of Cu with the 2p orbitals of its nearest-neighboring O atoms. Interestingly, we observe four van Hove singularities on these two flat bands, indicating electronic instability towards structural distortions at low temperatures. Furthermore, we show that the band energies of the van Hove singularities can be tuned by including electronic correlation effects or doping with different elements. We find that among the considered doping elements (Ni, Cu, Zn, Ag, and Au), both Ni and Zn doping result in the gap opening, whereas Au exhibits doping effects more similar to Cu than Ag. Our work provides a foundation for future studies on the role of unique electronic structures of LK-99 in superconductivity.

[johnwalker]

Next, on 2023-08-01, we have a second theoretical paper up on arXiv, “Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite” (full text at the link), by Sinéad M. Griffin of the Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, reporting density functional theory calculations of the LK-99 material reported to exhibit high-temperature superconductivity. Here is the abstract.

A recent report of room temperature superconductivity at ambient pressure in Cu-substituted apatite (`LK99’) has invigorated interest in the understanding of what materials and mechanisms can allow for high-temperature superconductivity. Here I perform density functional theory calculations on Cu-substituted lead phosphate apatite, identifying correlated isolated flat bands at the Fermi level, a common signature of high transition temperatures in already established families of superconductors. I elucidate the origins of these isolated bands as arising from a structural distortion induced by the Cu ions and a chiral charge density wave from the Pb lone pairs. These results suggest that a minimal two-band model can encompass much of the low-energy physics in this system. Finally, I discuss the implications of my results on possible superconductivity in Cu-doped apatite.

Here is Andrew Cote’s take on the paper, posted on Twitter within an hour of its publication.

This is the final paragraph of the “Discussion” section at the end of the original paper.

Finally, the calculations presented here suggest that Cu substitution on the appropriate (Pb(1)) site displays many key characteristics for high-{\rm T}_C superconductivity, namely a particularly flat isolated d-manifold, and the potential presence of fluctuating magnetism, charge and phonons. However, substitution on the other Pb(2) does not appear to have such sought-after properties, despite being the lower-energy substitution site. This result hints to the synthesis challenge in obtaining Cu substituted on the appropriate site for obtaining a bulk superconducting sample. Nevertheless, I expect the identification of this new material class to spur on further investigations of doped apatite minerals given these tantalizing theoretical signatures and experimental reports of possible high-{\rm T}_C superconductivity.

[johnwalker]

On 2023-08-01, we have what appears to be the first report of an apparent replication of the LK-99 room temperature superconductivity results. This was posted on bilibili.com by two researchers at the School of Materials Science and Technology of Huazhong University of Science and Technology in China, which shows partial levitation of a flake of LK-99 they report having made. The video cannot be embedded here but may be viewed at the following links:

• LK-99验证 (Original Chinese)
• LK-99 Verification (English translation by Google Translate)
• Observing the magnetic reaction of a material under a magnet using a microscope (Translation of Chinese narration to English by Targum.video)

The description of the video, translated to English by Google Translate, is:

Under the guidance of Professor Chang Haixin, postdoctoral Wu Hao and doctoral student Yang Li of the School of Materials Science and Technology of Huazhong University of Science and Technology successfully verified and synthesized the LK-99 crystal that can be magnetically levitated for the first time. Larger, it is expected to realize the real non-contact superconducting magnetic levitation.

A follow-up video, also translated by Targum.video, “Testing the sample with a magnet” purports to show testing the sample with a magnet to demonstrate it’s not ferromagnetic. I cannot see the sample in the portrait mode blur-o-vision video posted.

Here is Andrew Cote’s analysis of the first video. The original tweet included an embed of the video above which I have elided because Twitter videos cannot be embedded here.

[johnwalker]

Events of the last few days (see the three previous comments) appear to have changed the minds of punters in the prediction markets Manifold and Polymarket. (See discussion of these prediction markets in comments above: #7 [Manifold], #9 [Polymarket]).

Manifold

Polymarket

[jabowery]

@johnwalker

Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, reporting density functional theory calculations of the LK-99 material reported to exhibit high-temperature superconductivity.

So the materials parameter space has a theoretically identified gradient toward room temperature superconductivity which is compute-tractable, as just demonstrated by LBNL, and there hasn’t been an all-out effort to throw massive gradient descent (such as Adaptive Simulated Annealing to avoid local minima traps) ML at the problem?

[johnwalker]

And now, along comes another room-temperature superconductor patent, U.S. Patent 11,710,584 [PDF]. This appears to have nothing to do with the composition and structure of the Korean LK-99 material discussed so far. Here is the abstract of the patent.

A Type II superconductor includes a perforated carbonaceous material with an activating material on at least one surface. The activating material a non-polar liquid that does not incorporate Pi-bonding in its structure. The superconductor is manufactured by perforating a carbonaceous material to produce voids and coating at least one surface of the carbonaceous material with the activating material. A superconductive cable includes wires with a perforated carbonaceous material wetted with the activating material on a non-conductive substrate interspersed with non-conducting spacers and surrounded by an insulation layer. The superconductor conducts current at room temperature and above.

The patent application was filed on 2021-02-19 and granted on 2023-08-25. The company to which the patent is assigned, Taj Quantum, headquartered in Howey in the Hills, Florida, in the U.S. issued a press release on 2023-07-31:

Patent: Above Room Temperature Type II Superconductor - Taj Quantum

Taj Quantum, a pioneer in quantum technology and blockchain-based authentication systems, is pleased to announce the awarding of a patent by the United States Patent and Trademark Office (USPTO) for its Above Room Temperature Type II Superconductor. This unique type II superconductor, patent #17249094, operates at a wide range of temperatures – including those well above room temperature, from about -100° F (-73° C) to about 302° F (150° C) – a characteristic uncommon in the world of superconductors

Inventors John Wood and Paul Lilly, renowned for their extensive work with graphene and related materials, celebrated the announcement. “We are living in thrilling times where new discoveries are being made across a variety of fields,” said John Wood. Paul Lilly added, “Our main objective is to pinpoint applications that can rapidly benefit everyone by providing the quickest-to-market capability.”

Founded originally as LGC in 2018 by Paul Lilly, Taj Quantum has grown exponentially over the past year, securing numerous contracts supporting the U.S. Military and large businesses. This superconductor patent marks a significant milestone in the company’s mission to drive scientific advancements.

“We are in an odd position holding a patent to a technology that could prove revolutionary in many fields. The last thing we want to do is gatekeep access to further scientific developments. We are working with our attorneys to develop a means to open-source our technology for Universities and non-profit groups while retaining rights associated with monetizing derivative technologies without burdening those technologies. It’s a fine line that we need to walk,” said TQ CEO Paul Lilly.

As the company continues to grow and innovate, Taj Quantum is committed to hiring a new scientific team and building associated laboratory and production facilities. They aim to bring this superconductor technology into everyday electronics over the next decade.

Note that the press release incorrectly states the patent number as “#17249094”, which is actually a garbled transcription of the patent application number, assigned at the filing on 2021-02-19, and properly stated as 17/249,094. This error has been faithfully propagated by the “journalist”-stenographers who massaged the press release into breathy media accounts.

The press release shows this picture, captioned “Taj Quantum Type II Superconductor (Graphene foam-based)”.

The picture appears to show what purports to be a superconductor partially levitating (I think it’s touching at the left) above what one supposes to be a magnet. The picture looks to have been taken on a granite countertop identical to the one in the Fourmilab kitchen.

The patent shows this drawing of a notional superconducting cable, with parts identified as…

… a superconducting unit or wire 20 with a non-conductive core or support 22, coated with a layer of activating material 24, a layer of perforated graphene 26 (e.g., wrapped therearound), and an exterior coat of activating materials 28.

Notably absent from the press release, patent, or the company Web site is any mention of experimental results confirming that this “invention” is actually a superconductor. In fact, as discovered by @CTLaw, the patent states under “Detailed Description”:

The present invention provides a type II superconductor that is operative to conduct current at a wide range of temperatures from about −100° F. (about −73° C.) to about 302° F. (about 150° C.), such as about −80° F. (about −62° C.) to about 120° F. (about 49° C.) or about −10° F. (−23° C.) to about 180° F. (about 82° C.).

which, if you read it with the right kind of eyes, doesn’t actually say it is superconductive at the stated temperatures. This would also be true of a cuprate superconductor that is superconductive at liquid nitrogen temperatures but conducts weakly and resistively within the given high temperature range.

OK, Florida Man has checked in with a room temperature superconductor. Who’s next?

[CTLaw]

@johnwalker

And now, along comes another room-temperature superconductor patent, U.S. Patent 11,710,584 [PDF].

The European counterpart has not yet been examined.

Ditto Canada

Ditto Australia