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

In a paper posted on arXiv on 2023-07-23, three researchers from the Quantum Energy Research Centre, Inc. and KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, South Korea, report the production and test of a lead-apatite material which they claim exhibits all of the phenomena of superconductivity at room temperatures and above (they state its critical temperature, below which it is a superconductor, as 400 K, or 127° C) and ambient atmospheric pressure at sea level. Here is the paper.

Full text, in PDF form, is available at the link. The abstract is as follows:

For the first time in the world, we succeeded in synthesizing the room-temperature superconductor (T_c\geq 400 {\rm K}, 127∘ C) working at ambient pressure with a modified lead-apatite (LK-99) structure. The superconductivity of LK-99 is proved with the Critical temperature (T_c), Zero-resistivity, Critical current (I_c), Critical magnetic field (H_c), and the Meissner effect. The superconductivity of LK-99 originates from minute structural distortion by a slight volume shrinkage (0.48 %), not by external factors such as temperature and pressure. The shrinkage is caused by {\rm Cu}^{2+} substitution of {\rm Pb2}^{+}(2) ions in the insulating network of Pb(2)-phosphate and it generates the stress. It concurrently transfers to Pb(1) of the cylindrical column resulting in distortion of the cylindrical column interface, which creates superconducting quantum wells (SQWs) in the interface. The heat capacity results indicated that the new model is suitable for explaining the superconductivity of LK-99. The unique structure of LK-99 that allows the minute distorted structure to be maintained in the interfaces is the most important factor that LK-99 maintains and exhibits superconductivity at room temperatures and ambient pressure.

These illustrations from the paper show the structure of the synthesised material.

This paper is the first scientific disclosure of these results. The posting on arXiv lists no submission to or acceptance of the paper by a peer-reviewed journal. However, @CTLaw has found three filings with the Korean patent office regarding this work, all filed in March 2023 with a “Priority date” (whatever that is) of 2021-08-25:

The menu at the left of these items allows viewing description, claims, cited, and citing documents, with buttons to machine translate from Korean where required. No other patent filings have been found so far.

This silent video from the Quantum Energy Research Centre, institution of two of the co-authors, purports to show repulsion of a copper disc with a thermally deposited coating of the LK-99 material from a permanent magnet, as would be expected to occur from a superconductor manifesting the Meissner effect.

Another video, which cannot be embedded here, claims to show levitation of a sample of LK-99 above a permanent magnet: “Superconductor {\rm Pb}_{10−x}{\rm ​Cu}_x​({\rm PO}_4​)_{6 O}​ showing levitation at room temperature and atmospheric pressure and mechanism”. Note that the corner of the material never actually rises above the magnet.

In both of these magnetic repulsion videos, keep in mind that magnetic repulsion and/or levitation are not, by themselves, probative of superconductivity: a diamagnetic material such as pyrolytic graphite, can be made to levitate in a magnetic field without being superconductive.

Here are some additional causes for caution by “some guy on the Internet”.


This is, of course, far from the first time we’ve discussed high-temperature or room-temperature superconductivity here. See these earlier posts:

Unlike earlier claims, which were based upon material under extreme pressure in a diamond anvil cell, this paper claims superconductivity under ordinary laboratory conditions, and rather than exotic materials such as lutetium hydride compounds, uses a phosphate of lead doped with copper, which a competent chemist should be able to whip up and test for themselves, which I presume is going on as I write in laboratories around the world.

There’s no need among this audience to explain the technological consequences of discovery of room temperature, ambient pressure superconductivity. If the effect is genuine, and materials can be engineered which retain their superconductivity under the high magnetic fields of power transmissions (which has been a limitation of the cuprate superconductors that operate at liquid nitrogen temperatures), this may spark a revolution in electronics as significant as the invention of the transistor, vacuum tube, and induction motor.

We’ll see.

(The Korea Institute of Science and Technology, home of one of the co-inventors was, in the 1970s, a Marinchip Systems customer.)


Oh, I hadn’t thought about the induced magnetic field in a high current superconductor. Yes, that could be a problem.


Engineer attempting to replicate:

Click image to view complete Twitter thread, updated as the project progresses.

Update: I have edited this post because the original link, as posted, cannot be viewed by those without a Twitter account. A link to a specific tweet, however, can be viewed by anybody. Users without a Twitter account will see only the first tweet; you must be logged in to see the thread that follows it. (@Fourmilab 2023-07-27 12:20 UTC)


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.

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.

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.


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:

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.


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”.


Any better?


Well, on Polymarket they’re betting the USDCstablecoin”, 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.


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.


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!


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.

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:

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

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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

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





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

Stay tuned for the gripping next episode!


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.



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.

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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.


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 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:

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, “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.



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]).



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