LK-99: Difference between revisions
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Early replication efforts gained global visibility, with the aid of online replication trackers that cataloged new announcements and status updates.<ref name="ferr">{{cite web |last1=Ferreira |first1=Becky |last2=Pearson |first2=Jordan |date=1 August 2023 |title=DIY Scientists and Institutions Are Racing to Replicate the Room-Temperature Superconductor |url=https://www.vice.com/en/article/5d9yez/diy-scientists-and-institutions-are-racing-to-replicate-the-room-temperature-superconductor |url-status=live |archive-url=https://web.archive.org/web/20230802153947/https://www.vice.com/en/article/5d9yez/diy-scientists-and-institutions-are-racing-to-replicate-the-room-temperature-superconductor |archive-date=2 August 2023 |access-date=2 August 2023 |website=Vice |language=en}}</ref> Some researchers released brief teaser images or videos before publishing any results, which received great public attention. On 1 August 2023, a team at [[Huazhong University of Science and Technology]] in China reported producing tiny flakes that showed diamagnetic levitation, on their second attempt.<ref name="lowe-20230801">{{Cite news |last=Lowe |first=Derek |author-link=Derek Lowe (chemist)|date=2023-08-01 |department=Chemical News|title=A Room-Temperature Superconductor? New Developments |url=https://www.science.org/content/blog-post/room-temperature-superconductor-new-developments |url-status=live |access-date=2023-08-01 |work="In the pipeline" |type=blog |via=[[Science (journal)|Science]].org|publisher=[[American Association for the Advancement of Science]]|archive-date=2023-08-01 |archive-url=https://web.archive.org/web/20230801202928/https://www.science.org/content/blog-post/room-temperature-superconductor-new-developments }}</ref> On 2 August 2023, a team around Prof. Sun Yue at [[Southeast University]], claimed to have measured zero resistance in a flake of LK-99 up to a temperature of {{convert|110|K|C F|lk=in}}.<ref name="targ">{{Cite web |title=Research on LK-99 Superconductor at Southeast University |url=https://targum.video/embed/388e770217a654ba9175b391eedd7802 |access-date=2023-08-02 |website=targum.video |archive-date=2 August 2023 |archive-url=https://web.archive.org/web/20230802232401/https://targum.video/embed/388e770217a654ba9175b391eedd7802 |url-status=live }}</ref> Doubts were expressed by experts in the field (from the [[University of Maryland]]) that their results had what looked like a large measurement artifact, did not show the expected dropoff to zero resistance, and were quite noisy and unable to measure resistance below 10 µΩ, which is high for measurements of superconductors.<ref name=":1">{{Cite twitter |user=condensed_the |number=1686895266329174016 |title=Southeast may have drawn their figure misleadingly. On a linear scale, there seems to be no transition, very disappointing and not a good sign since the artifact also looms large |url=https://twitter.com/condensed_the/status/1686895266329174016 |access-date=2023-08-03 |language=en}}</ref> |
Early replication efforts gained global visibility, with the aid of online replication trackers that cataloged new announcements and status updates.<ref name="ferr">{{cite web |last1=Ferreira |first1=Becky |last2=Pearson |first2=Jordan |date=1 August 2023 |title=DIY Scientists and Institutions Are Racing to Replicate the Room-Temperature Superconductor |url=https://www.vice.com/en/article/5d9yez/diy-scientists-and-institutions-are-racing-to-replicate-the-room-temperature-superconductor |url-status=live |archive-url=https://web.archive.org/web/20230802153947/https://www.vice.com/en/article/5d9yez/diy-scientists-and-institutions-are-racing-to-replicate-the-room-temperature-superconductor |archive-date=2 August 2023 |access-date=2 August 2023 |website=Vice |language=en}}</ref> Some researchers released brief teaser images or videos before publishing any results, which received great public attention. On 1 August 2023, a team at [[Huazhong University of Science and Technology]] in China reported producing tiny flakes that showed diamagnetic levitation, on their second attempt.<ref name="lowe-20230801">{{Cite news |last=Lowe |first=Derek |author-link=Derek Lowe (chemist)|date=2023-08-01 |department=Chemical News|title=A Room-Temperature Superconductor? New Developments |url=https://www.science.org/content/blog-post/room-temperature-superconductor-new-developments |url-status=live |access-date=2023-08-01 |work="In the pipeline" |type=blog |via=[[Science (journal)|Science]].org|publisher=[[American Association for the Advancement of Science]]|archive-date=2023-08-01 |archive-url=https://web.archive.org/web/20230801202928/https://www.science.org/content/blog-post/room-temperature-superconductor-new-developments }}</ref> On 2 August 2023, a team around Prof. Sun Yue at [[Southeast University]], claimed to have measured zero resistance in a flake of LK-99 up to a temperature of {{convert|110|K|C F|lk=in}}.<ref name="targ">{{Cite web |title=Research on LK-99 Superconductor at Southeast University |url=https://targum.video/embed/388e770217a654ba9175b391eedd7802 |access-date=2023-08-02 |website=targum.video |archive-date=2 August 2023 |archive-url=https://web.archive.org/web/20230802232401/https://targum.video/embed/388e770217a654ba9175b391eedd7802 |url-status=live }}</ref> Doubts were expressed by experts in the field (from the [[University of Maryland]]) that their results had what looked like a large measurement artifact, did not show the expected dropoff to zero resistance, and were quite noisy and unable to measure resistance below 10 µΩ, which is high for measurements of superconductors.<ref name=":1">{{Cite twitter |user=condensed_the |number=1686895266329174016 |title=Southeast may have drawn their figure misleadingly. On a linear scale, there seems to be no transition, very disappointing and not a good sign since the artifact also looms large |url=https://twitter.com/condensed_the/status/1686895266329174016 |access-date=2023-08-03 |language=en}}</ref> |
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Revision as of 12:22, 4 August 2023
This article may be affected by a current scientific claim. Information in this article may change rapidly as the event progresses. Initial news reports may be unreliable. The last updates to this article may not reflect the most current information. (July 2023) |
![]() | |
![]() 3D structure
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Identifiers | |
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3D model (JSmol)
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|
| |
| |
Properties | |
CuO25P6Pb9 | |
Molar mass | 2514.2 g·mol−1 |
Appearance | grey black solid |
Density | ≈6.699 g/cm3[1] |
Structure | |
hexagonal | |
P63/m, No. 176 | |
a = 9.843 Å, c = 7.428 Å
| |
Lattice volume (V)
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623.2 Å3 |
Formula units (Z)
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1 |
Related compounds | |
Related compounds
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Oxypyromorphite (lead apatite) |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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LK-99 (from the Lee-Kim 1999 research),[2] is a potential room-temperature superconductor with a gray-black appearance.[3]: 8 It is said to have a hexagonal structure that is slightly modified from lead‒apatite by adding small amounts of copper. The team from Korea University, led by Sukbae Lee (이석배) and Ji-Hoon Kim (김지훈), first recognized this material as an anomaly in 1999.[3]: 1 According to their claims, LK-99 acts as a superconductor at temperatures below 400 K (127 °C; 260 °F) and at ambient pressure.[2][4][3]: 1
As of 4 August 2023, the scientific community has not validated the claims of superconductivity for LK-99, especially at room temperature, through peer-reviewed processes or independent replication by other research groups.[5] There was one report of observed superconductivity at 110 K by a team from Southeast University, China. However, the absence of the Meissner effect (a defining characteristic of superconductors) and the unique conditions under which these results were obtained raised doubts about the validity of the claim. The scientific world reacted skeptically to the announcement due to the extraordinary nature of the claims,[6] previous failures in proving room-temperature superconductors, and errors and inconsistencies in the pre-published papers. Independent research teams are currently attempting to replicate the work of the South Korean team. Results are expected in August 2023, as the process of producing the material is straightforward.[6]
The initial studies announcing the discovery of LK-99 were uploaded to the open-access repository of electronic preprints, arXiv. There were statements made by Lee, claiming the uploaded preprint papers were incomplete,[7] and coauthor Hyun-Tak Kim (김현탁) stated that one of the papers contained defects.[8]
Chemical properties and structure
The chemical composition of LK-99 is approximately Pb9Cu(PO4)6O such that—compared to pure lead-apatite (Pb10(PO4)6O)[9]: 5 —approximately one quarter of Pb(II) ions in position 2 of the apatite structure are replaced by Cu(II) ions.[3]: 9
The structure is similar to that of apatite, space group P63/m (No. 176).
Synthesis
Lee et al. provide a method for chemical synthesis of LK-99 material[9]: 2 by producing lanarkite from a 1:1 molar mixing of lead(II) oxide (PbO) and lead(II) sulfate (Pb(SO4)) powders, then heating at 725 °C (1,000 K; 1,340 °F) for 24 hours:
- PbO + Pb(SO4) → Pb2(SO4)O
Additionally, copper(I) phosphide (Cu3P) was produced by mixing copper (Cu) and phosphorus (P) powders in a 3:1 molar ratio in a sealed tube under a vacuum and heated to 550 °C (820 K; 1,000 °F) for 48 hours:[9]: 3
- 3 Cu + P → Cu3P
Lanarkite and copper phosphide crystals were ground into a powder, placed in a sealed tube under a vacuum, and heated to 925 °C (1,200 K; 1,700 °F) for between 5‒20 hours:[9]: 3
- Pb2(SO4)O + Cu3P → Pb10-xCux(PO4)6O + S (g), where (0.9 < x < 1.1)
The above reaction may not be balanced. A paper by Kapil Kumar et al. reported the presence of Cu2S as well.[10] A balanced reaction might be:
- 5 Pb2SO4O + 6 Cu3P → Pb9Cu(PO4)6O + 5 Cu2S + Pb + 7 Cu[citation needed]
Physical properties
![](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/LK-99_magnetic_properties.png/220px-LK-99_magnetic_properties.png)
The material is claimed to be a room-temperature superconductor.[9]: 1 The original published articles do not claim to have seen definitive features of superconductivity, zero resistance and the Meissner effect, but show the material exhibiting strong diamagnetic properties, including a video of sample of the material partially levitating on top of a large magnet,[9] which is correlated with superconductivity.
As many materials can spuriously seem like potential candidates for high-temperature superconductivity,[11] in addition to a zero-resistance mode and a clear Meissner effect, researchers generally also demonstrate other expected properties such as flux pinning, AC magnetic susceptibility, the Josephson effect, a temperature-dependent critical field and current, or a sudden jump in specific heat around the critical temperature.[12] As of August 1, none of these have been observed by the original experiment or attempted replications.[13]
Proposed mechanism for superconductivity
Partial replacement of Pb2+ ions (measuring 133 picometres) with Cu2+ ions (measuring 87 picometres) is said to cause a 0.48% reduction in volume, creating internal stress inside the material.[3]: 8 The internal stress is claimed to cause a heterojunction quantum well between the Pb(1) and oxygen within the phosphate ([PO4]3−) generating a superconducting quantum well (SQW).[3]: 10
Lee et al. claim to show LK-99 exhibits a response to a magnetic field (potentially due to the Meissner effect) when chemical vapor deposition is used to apply LK-99 to a non-magnetic copper sample.[3]: 4 Pure lead-apatite is an insulator, but Lee et al. claim copper-doped lead-apatite forming LK-99 is a superconductor, or at higher temperatures, a metal.[9]: 5 They do not claim to have observed any change in behavior across a transition temperature.[citation needed]
The paper's mechanisms were based on a 2021 paper[14] by Hyun-Tak Kim describing a novel "BR-BCS" theory of superconductivity combining a classical theory of metal-insulator transitions[15] with the standard Bardeen–Cooper–Schrieffer theory of superconductivity. They also use ideas from the theory of hole superconductivity[16] by J.E.Hirsch, another controversial work.
On 1 August 2023, three independent groups published analyses of LK-99 with density functional theory (DFT). Sinéad Griffin of Lawrence Berkeley National Laboratory analyzed it with the Vienna Ab initio Simulation Package, showing that its structure would have correlated isolated flat bands, one of the signatures of high-transition-temperature superconductors.[17] Si and Held[18] found similar flat bands and conjectured that LK-99 is a Mott or charge transfer insulator, that electron or hole doping is needed to make it (super)conducting.
Compound name
The name LK-99 is from the initials of discoverers Sukbae Lee and Ji-Hoon Kim, and the year of discovery (1999).[2] The pair had originally been working with Professor Tong-Shik Choi (최동식) at Korea University in the 1990s.[19]
In 2008, researchers from Korea University founded the Quantum Energy Research Centre (퀀텀 에너지연구소; also known as Q-Centre).[7] Lee would later become CEO of Q-Centre, and Kim would become director of research and development (R&D) at Q-Centre.
Publication history
Lee has stated that in 2020, an initial paper was submitted to Nature, but was rejected.[19] Similarly-presented research on room-temperature superconductors (but a totally different chemical system) by Ranga P. Dias had been published in Nature earlier that year, and received with skepticism—Dias's paper would subsequently be retracted in 2022 after its data was questioned as having been falsified.[20]
In 2020, Lee and Ji-Hoon Kim filed a patent application.[21] A second patent application (additionally listing Young-Wan Kwon), was filed in 2021, which was published on 3 March 2023.[22] On 4 April 2023, a Korean trademark application for "LK-99" was filed by the Q-Centre.[23]
In February 2023, the Q-Centre published a video on YouTube claiming to show the magnetic properties of a thin layer of LK-99 thermally deposited on a copper plate.[24]
Scholarly articles and preprints
A series of academic publications summarizing initial findings came out in 2023, with a total of seven authors across four publications.
On 31 March 2023, a Korean-language paper, "Consideration for the development of room-temperature ambient-pressure superconductor (LK-99)", was submitted to the Korean Journal of Crystal Growth and Crystal Technology.[4] It was accepted on 18 April, but was not widely read until three months later.
On 22 July 2023, two preprints appeared on arXiv. The first submitted listed Young-Wan Kwon, former Q-Centre CTO, as third author.[3] The second preprint listed as third author Hyun-Tak Kim, former principal researcher at the Electronics & Telecommunications Research Institute and professor at the College of William & Mary, as well as three new authors.[9][25] On 23 July, the findings were also submitted to APL Materials for peer review.[19][7]
On 28 July 2023, Kwon presented the findings at a symposium held at Korea University.[26][27][28] That same day, Yonhap News Agency published an article quoting an official from Korea University as saying that Kwon was no longer in contact with the University.[7] The article also quoted Lee saying that Kwon had left the Q-Centre Research Institute four months previously;[7] that the academic papers on LK-99 were not finished and contained many defects; and that the papers had been uploaded to arXiv without the other authors' permission.[7][25]
On 31 July 2023, a group led by Kapil Kumar published a preprint on arXiv documenting their replication attempts, which confirmed the structure using X-ray crystallography (XRD) but failed to find diamagnetism or levitation.[10]
On 1 August 2023, a Q-Centre representative told SBS News that the original samples referenced in the paper would be released to the world for verification soon.[29]
On 3 August 2023, the Korean LK-99 Verification Committee requested a high-quality sample from the original research team. However, the team responded that they would only provide the sample once the review process of their paper, potentially submitted to APL Materials, is completed. This process is expected to take several weeks or months.[30]
On the same day, Hyun-Tak Kim, one of the authors of the 6 author July 22 arXiv-LK-99 paper, provided the New York Times with a new video presumably showing a sample displaying strong signs of diamagnetism.[2] The video appears to show a sample different to the one in the original preprint, suggesting the group's ability to reproduce their samples.
On 4 August 2023, Kim Hyun-tak informed SBS News that high-quality LK-99 samples may exhibit diamagnetism 5,450 times greater than graphite, while low-quality samples may demonstrate an effect up to 23 times stronger. Moreover, he claimed that the diamagnetism of LK-99 is inexplicable unless the substance is a superconductor [31], a hypothesis also proposed in a theoretical paper on LK-99 by TU Wien and Northwest University.
Authors
Author credit[a 1] and affiliation matrix:
Author Affiliation
|
Lee, Sukbae (이석배) |
Kim, Ji-Hoon (김지훈) |
Kim, Hyun-Tak (김현탁) |
Im, Sungyeon (임성연) |
An, SooMin (안수민) |
Kwon, Young-Wan (권영완) |
Auh, Keun Ho (오근호) |
Choi, Tong-Shik (최동식) |
---|---|---|---|---|---|---|---|---|
HYU | Professor Emeritus | |||||||
KU‒KIST | 'former Professor[7]† | |||||||
W&M | Professor | |||||||
Q-Centre (주)퀀텀에너지연구소 | CEO | R&D Director | Yes | Yes | 'former CTO[7] | CTO | ||
Patent (2020)[21] | 1 | 2 | ||||||
Patent Application (2021)[22] | 1 | 2 | 3 | |||||
Lee & Kim+ (18 April 2023)[4] | 1 | 2 | 3 | 4 | 5 | 6 | Acknowledged | |
Lee & Kim+ (22 July 2023.a)[3] | 1 | 2 | Acknowledged | Acknowledged | 3 | Acknowledged | ||
Lee & Kim+ (22 July 2023.b)[9] | 1 | 2 | 3 | 4 | 5 | Acknowledged | 6 | Acknowledged |
Response
Materials scientists and superconductor researchers responded with skepticism.[8] The highest-temperature superconductors known at the time of publication had a critical temperature of 250 K (−23 °C; −10 °F) at pressures of over 170 gigapascals (1,680,000 atm; 24,700,000 psi). The highest-temperature superconductors at atmospheric pressure (1 atm) had a critical temperature of at most 150 K (−123 °C; −190 °F).
On 2 August 2023, the The Korean Society of Superconductivity and Cryogenics established a verification committee as a response to the controversy and unverified claims of LK-99, in order to arrive at conclusions over these claims. The verification committee is headed by Prof. Kim Chang-Young of Seoul National University and consists of members of the university, Sungkyunkwan University and Pohang University of Science and Technology. Upon formation, the verification committee did not agree that the two 22 July arXiv papers by Lee et al. or the publicly available videos at the time supported the claim of LK-99 being a superconductor.[25][32]
As of 4 August 2023[update], the measured properties do not prove that LK-99 is a superconductor as the published material does not fully explain how the LK-99's magnetisation can change, demonstrate its specific heat capacity, or demonstrate it crossing its transition temperature.[8] An alternative explanation for LK-99's stated partial magnetic levitation could be solely from non-superconductive diamagnetism.[25][33]
Public response
The claims of a room temperature superconductor in the 22 July papers by Lee et al. went viral on social media platforms the following week,[6] including Twitter and Reddit.[34] The viral nature of the claim resulted in posts from users using pseudonyms from Russia and China claiming to have replicated LK-99 on both Twitter and Zhihu.[35] Despite interest from commentators, scientists interviewed by the press remained skeptical.[36][37] Reasons given for skepticism included issues with the Lee et al. July 22 preprint papers, the lack of purity in the sample reported by Lee et al. and the failure of previous claims of room temperature superconductivity to show legitimacy.[25] The Korean Society of Superconductivity and Cryogenics has expressed concern on the social and economic impacts of the LK-99 research, as it has not been verified nor peer-reviewed.[38]
A video from Huazhong University of Science and Technology uploaded on 1 August 2023 by a postdoctoral researcher on the team of Dr. Chang Haixin,[25] apparently showed a micrometre-sized sample of LK-99 levitating that went viral on Chinese social media. Gathering millions of views, it became the second most viewed video on Bilibili the next day.[39] On August 3rd it became the most viewed video on Bilibili with 9 million views.[25] A researcher from the Chinese Academy of Sciences refused to comment on the video for the press, dismissing the claim as "ridiculous".[39] Public excitement grew after the video made its way to western social media, with a prediction market briefly putting the chance of successful replication at 60%.[40] As the topic of LK-99 trended on Twitter for days at the start of August, users began to create memes about "floating rocks" and suggested backing stocks in superconductors.[41] It was concurrently reported in the press that the study had caused a surge in Korean and Chinese technology stocks,[42][43][44] despite warnings from the Korean stock exchange against speculative bets in light of the excitement around LK-99.[38]
Replication attempts
As of 4 August 2023[update], the experiment has not been successfully replicated, despite the initial experiments being completed in 2020. No replication attempts have yet been peer-reviewed. After the July 2023 publications release, independent groups reported that they had begun attempting to reproduce the synthesis, with initial results expected within weeks.[6] However while positive results can come quickly, negative results are slow, as "falsification needs to verify all possibilities, and it will take a lot of time."[45]
The first attempts that published results did not observe levitation or diamagnetism, and their samples had high resistivity. None have published tests of flux pinning or specific heat capacity.
Early replication efforts gained global visibility, with the aid of online replication trackers that cataloged new announcements and status updates.[35] Some researchers released brief teaser images or videos before publishing any results, which received great public attention. On 1 August 2023, a team at Huazhong University of Science and Technology in China reported producing tiny flakes that showed diamagnetic levitation, on their second attempt.[13] On 2 August 2023, a team around Prof. Sun Yue at Southeast University, claimed to have measured zero resistance in a flake of LK-99 up to a temperature of 110 K (−163 °C; −262 °F).[46] Doubts were expressed by experts in the field (from the University of Maryland) that their results had what looked like a large measurement artifact, did not show the expected dropoff to zero resistance, and were quite noisy and unable to measure resistance below 10 µΩ, which is high for measurements of superconductors.[47]
![]() |
Results Key: Success Partial Success Partial Failure Failure
Group[a 1] | Country | Status | Results | Publication Notes |
---|---|---|---|---|
Huazhong University of Science and Technology | ![]() |
Preliminary | Video claiming to show diamagnetism of small (< 0.1 mm) flakes of LK-99. Reportedly making a new batch to measure resistance. | arXiv: Hao Wu, et al.[48]
Video posted to bilibili[49][50] claims team includes Prof. Chang Haixin. |
Beihang University | Preliminary | No diamagnetism observed. LK-99 sample had high resistivity not consistent with superconductivity. | arXiv: Li Liu, et al.[51] | |
Southeast University | Preliminary | Synthesized LK-99, structure confirmed by x-ray diffraction. Resistance of mm-sized sample gradually reduced from 0.1Ω at room temperature to noise level (10-5Ω) at 110 K and below. No observed Meissner effect. | arXiv: Qiang Hou, et al.[53]
Critical review by researchers from the Condensed Matter Theory Center at the University of Maryland.[47] | |
Shanghai University | Unpublished | LK-99 powder was measured for magnetic susceptibility. Preliminary results observed no diamagnetism. | News report: on-site interview by reporter[55] | |
Qufu Normal University | Unpublished | Zero resistance not observed in sample. | Press Coverage:[44] | |
National Physical Laboratory of India (CSIR-NPLI) | ![]() |
Preliminary | Structure confirmed by x-ray diffraction. No diamagnetism observed. Measurements of superconductivity incomplete. | arXiv: Kapil Kumar, et al.[10][56][57] |
Varda Space Industries & University of Southern California | ![]() |
Unpublished | Video showing partial levitation of small flake. | Video shared on Twitter:[58]
Team headed by Andrew McCalip. Livestreaming on Twitch and posting on Twitter. Samples to be analysed by University of Southern California.[59] |
Argonne National Laboratory | Unknown | Not reported | Press coverage:[25][60][35] | |
Sungkyunkwan University | ![]() |
Unknown | Not reported | Supporting the committee reportedly evaluating the claims about LK-99.[32]
Press coverage:[25] |
Korea University | Unknown | Not reported | ||
Seoul National University | Unknown | Not reported |
Theoretical studies
In the initial papers, the theoretical explanations for potential mechanisms of superconductivity in LK-99 were incomplete. Later analyses by other labs have added further simulations and theoretical evaluations of the material's electronic properties from first principles.
Group | Country | Result | Publication notes |
---|---|---|---|
Chinese Academy of Sciences (SYNL) | ![]() |
First-principles study of the electronic structure of LK-99 and other variants. Expresses no opinion on room-temp superconductivity, but suggests gold-doped lead apatite may have stronger effects. | arXiv: Junwen Lai, et al.[61]
Media mentions:[62] |
Lawrence Berkeley National Laboratory | ![]() |
DFT analysis on a simplified 3D structure explores possible electronic structure that could be favorable for superconductivity, suggests slightly decreased lattice constant. | arXiv: Sinéad Griffin[17][b 1] |
Northwest University & TU Wien | ![]() ![]() |
Similar results from DFT analysis. Conjectures superconductivity might be possible, but only when LK-99 is doped, and that diamagnetism without superconductivity is unlikely. | arXiv: Liang Si & Karsten Held[18][b 1] |
CU Boulder, National Renewable Energy Laboratory, & King's College | ![]() ![]() |
Similar results from DFT analysis. Conjectures this class of material (weak interaction of copper‒oxygen, while minimising hybridisation) shows promise for high-Tc superconductivity, regardless of realisation of LK-99. | arXiv: Rafal Kurleto, et al.[65][b 1] |
Institute of Mathematical Sciences, Chennai, IIT Madras | ![]() |
Theorises a mechanism for superconductivity within LK-99, in which copper chains in LK-99 act as a Mott insulator and interact with surrounding insulating elements. | arXiv: G. Baskaran[66] |
University of California, Irvine and University of Toronto | ![]() ![]() |
A minimal tight-binding model is proposed which reproduces the main features of the flat bands in LK-99 and informs a discussion on the symmetry of a putative superconducting order parameter. | arXiv: Omid Tavakol & Thomas Scaffidi[67] |
Universidad de Chile | ![]() |
DFT analysis, finding large electron-phonon coupling in the flat bands. | arXiv: J. Cabezas-Escares, et al.[68] |
- ^ a b c Density functional theory analyses (published on the same day, without seeing one another's work; largely overlapping analysis)
References
- ^ "2514.2 AMU /(sin(60°)*9.843*9.843*7.428 Å^3)". WolframAlpha (calculation). Archived from the original on 29 July 2023. Retrieved 29 July 2023.
- ^ a b c d Chang, Kenneth (3 August 2023). "LK-99 Is the Superconductor of the Summer". The New York Times. Archived from the original on 3 August 2023. Retrieved 3 August 2023.
Social media users are excited about what would be a breakthrough in solid state physics, but many experts in the field are cautiously skeptical.
- ^ a b c d e f g h i Lee, Sukbae; Kim, Ji-Hoon; Kwon, Young-Wan (22 July 2023). "The First Room-Temperature Ambient-Pressure Superconductor". arXiv:2307.12008.
- ^ a b c Lee, Sukbae; Kim, Ji-Hoon; Im, Sungyeon; An, Soomin; Kwon, Young-Wan; Auh, Keun Ho (31 March 2023). "Consideration for the development of room-temperature ambient-pressure superconductor (LK-99)". Korean Crystal Growth and Crystal Technology. 33 (2). Korea Association Of Crystal Growth: 61‒70. doi:10.6111/JKCGCT.2023.33.2.061. Archived from the original on 25 July 2023. Retrieved 25 July 2023.
- ^ Flaherty, Nick (26 July 2023). "Race is on for room temperature superconductor". Technology News. eeNews Europe. European Business. Archived from the original on 26 July 2023. Retrieved 26 July 2023.
published on the pre-print server arxiv.org and still has to go through peer review
- ^ a b c d Garisto, Dan (27 July 2023). "Viral New Superconductivity Claims Leave Many Scientists Skeptical". Materials science. Scientific American. Archived from the original on 27 July 2023. Retrieved 28 July 2023.
- ^ a b c d e f g h 조승한 (28 July 2023). 강의영 (ed.). '상온 초전도체 구현' 한국 연구에 국내외 논란…"검증 거쳐야" [Controversy both domestic and abroad regarding Korean development of room temperature superconductor … "It has to be verified"] (in Korean). Yonhap News Agency. Archived from the original on 28 July 2023. Retrieved 28 July 2023. … 논문이 아니며 공개도 의도한 바가 아니라고 선을 그었다. … 이 대표는 이날 연합뉴스와 통화에서 "다른 저자들의 허락 없이 권 연구교수가 임의로 아카이브에 게재한 것"이라며 "아카이브에 내려달라는 요청을 해둔 상황" 이라고 주장했다. … 이 대표는 권 연구교수가 퀀텀에너지연구소 최고기술책임자(CTO)로 있었지만 4개월 전 이사직을 내려놓고 현재는 회사와 관련이 없다고도 밝혔다. … 고려대 관계자에 따르면 권 연구교수는 현재 학교와도 연락이 닿지 않는 상황으로 알려졌다.
- ^ a b c Padavic-Callaghan, Karmela (26 July 2023). "Room-temperature superconductor 'breakthrough' met with scepticism". New Scientist. Archived from the original on 26 July 2023. Retrieved 26 July 2023.
Speaking to New Scientist, Hyun-Tak Kim at the College of William & Mary in Virginia says he will support anyone trying to replicate his team's work. … [HT] Kim has only co-authored one of the arXiv papers, while the other is authored by his colleagues at the Quantum Energy Research Centre in South Korea, … Both papers present similar measurements, however [HT] Kim says that the second [3-author] paper contains "many defects" and was uploaded to arXiv without his permission. … Once the findings are published in a peer-reviewed journal, … [HT] Kim says … he will support anyone who wants to create and test LK-99
- ^ a b c d e f g h i Lee, Sukbae; Kim, Ji-Hoon; Kim, Hyun-Tak; Im, Sungyeon; An, SooMin; Auh, Keun Ho (22 July 2023). "Superconductor Pb10−xCux(PO4)6O showing levitation at room temperature and atmospheric pressure and mechanism". arXiv:2307.12037.
- ^ a b c Kumar, Kapil (31 July 2023). "Synthesis of possible room temperature superconductor LK-99:Pb9Cu(PO4)6O". arXiv:2307.16402.
- ^ Fuhrer, Michael S. [@MichaelSFuhrer] (2 August 2023). "You'd think superconductivity would be easy to detect; it comes with zero electrical resistance, so if you measure resistance, and it's zero, you're done. Unfortunately there are many ways to get fooled" (Tweet). Retrieved 2 August 2023 – via Twitter.
- ^ Fuhrer, Michael S. [@MichaelSFuhrer] (2 August 2023). "So generally you'll see multiple pieces of evidence for superconductivity in a new report: Meissner effect, AC susceptibility, temperature-dependent critical field and critical current, single-particle tunnelling gap, jump in specific heat at T_c, Josephson tunnelling... etc" (Tweet). Retrieved 2 August 2023 – via Twitter.
- ^ a b c Lowe, Derek (1 August 2023). "A Room-Temperature Superconductor? New Developments". Chemical News. "In the pipeline" (blog). American Association for the Advancement of Science. Archived from the original on 1 August 2023. Retrieved 1 August 2023 – via Science.org.
- ^ Kim, Hyun-Tak (14 May 2021). "Room-temperature-superconducting Tc driven by electron correlation". Scientific Reports. 11 (1): 10329. doi:10.1038/s41598-021-88937-7. ISSN 2045-2322. Archived from the original on 25 July 2023. Retrieved 1 August 2023.
- ^ Brinkman, W. F.; Rice, T. M. (15 November 1970). "Application of Gutzwiller's Variational Method to the Metal-Insulator Transition". Physical Review B. 2 (10): 4302–4304. doi:10.1103/PhysRevB.2.4302. ISSN 0556-2805. Archived from the original on 2 August 2023. Retrieved 1 August 2023.
- ^ Hirsch, J. E. (23 January 1989). "Hole superconductivity". Physics Letters A. 134 (7): 451–455. doi:10.1016/0375-9601(89)90370-8. ISSN 0375-9601. Archived from the original on 9 July 2014. Retrieved 1 August 2023.
- ^ a b Griffin, Sinéad M. (31 July 2023). "Origin of correlated isolated flat bands in copper-substituted lead phosphate apatite". arXiv:2307.16892 [cond-mat.supr-con].
- ^ a b Si, Liang; Held, Karsten (1 August 2023). "Electronic structure of the putative room-temperature superconductor Pb9Cu(PO4)6O". arXiv:2308.00676 [cond-mat.supr-con].
- ^ a b c 이병철; 최정석 (27 July 2023). ‘노벨상감’ 상온 초전도체 세계 최초 개발했다는 한국 연구...과학계 ‘회의론’ 넘을까 [Korean study into world's first room-temperature superconductor … can it overcome scientific 'skepticism' … to win Nobel prize]. Chosun Biz (in Korean). Archived from the original on 27 July 2023. Retrieved 27 July 2023. 연구를 주도한 이석배 퀀텀에너지연구소 대표는 27일 오전 조선비즈와 만나 “2020년에 처음 연구 결과를 네이처에 제출했지만 다이어스 교수 사태 때문에 네이처가 논문 게재를 부담스러워했고, 다른 전문 학술지에 먼저 게재할 것을 요구했다”며 “국내 학술지에 먼저 올려서 국내 전문가의 검증을 받고 사전공개 사이트인 아카이브에 올린 것”이라고 말했다. 이 대표는 지난 23일 국제 학술지인 ‘ALP 머터리얼즈’에도 논문을 제출했다고 덧붙였다. 세계적인 물리학 저널에 인정을 받겠다는 설명이다. … “지금은 작고한 최동식 고려대 화학과 교수와 함께 1990년대 중반부터 상온 초전도체 구현을 위해 20년에 걸쳐 연구와 실험을 진행했다”고 말했다. 이 대표는 상압상온 초전도체에 대한 특허도 출원했다고 밝혔다.
- ^ Garisto, Dan (25 July 2023). "'A very disturbing picture': another retraction imminent for controversial physicist". Nature. doi:10.1038/d41586-023-02401-2. Archived from the original on 27 July 2023. Retrieved 28 July 2023.
- ^ a b KR20210062550A, 이석배 & 김지훈, "Method of manufacturing ceramic composite with low resistance including superconductors and the composite thereof", issued 2021-05-31 Archived 3 August 2023 at the Wayback Machine
- ^ a b KR published 2023027536A1, 이석배; 김지훈 & 권영완, "Ceramic composite with superconductivities over room temperature at atmospheric condition and method of manufacturing the ceramic composite", published 2023-03-02 Archived 2023-07-26 at the Wayback Machine
- ^ LK-99. Korea Intellectual Property Rights Information Service (Report). Korean Intellectual Property Office. 4 April 2023. Archived from the original on 26 July 2023. Retrieved 25 July 2023.
LK-99; … Applicant: Quantum Energy Research Centre (Q-Centre); … Status: Awaiting Examination
- ^ Magnetic Property Test of LK-99 Film. (주)퀀텀에너지연구소 (Q-Centre. Retrieved 2 August 2023 – via YouTube.
Recorded on [2023-01-26]. The sample was thermally deposited on a copper plate.
. - ^ a b c d e f g h i j k l Henshall, Will (3 August 2023). "Why Experts Are Skeptical About That Supposed Superconductor Breakthrough". Time. Archived from the original on 3 August 2023. Retrieved 3 August 2023.
- ^ Kwon, Young-Wan (28 July 2023). The World First: Room-Temperature Ambient-Pressure Superconductor. MML 2023: 11th International Symposium on Metallic Multilayers (conference presentation). Korea University, Seoul, Korea: The Korean Magnetics Society.
- ^ Seifert, Tom S. [@TeraTom_S] (28 July 2023). "Just listening to an impressive talk of one of the coauthors of the room-temperature superconductor #LK99 at Korea university, Young-Wan Kwon" (Tweet). Retrieved 28 July 2023 – via Twitter.
- ^ Bodin, Kenneth [@KennethBodin] (28 July 2023). "They have now also presented at MML2023. They took questions. Answers not entirely satisfying. Rumour is that MIT SC specialists are flying over to scrutinize experiments. (Photo @JohanaAkerman [Johaa Akerman])" (Tweet). Retrieved 28 July 2023 – via Twitter.
- ^ Jeong, Gu Hee (1 August 2023). "꿈의 물질 개발" 초전도체 뜨거운 관심…"샘플 곧 공개" ["Development of dream material" … Superconductor hot interest … "Sample to be released soon"]. SBS 8 News (video, offset 02:20) (in Korean). Seoul Broadcasting System (SBS). Retrieved 1 August 2023 – via Youtube. 퀀텀에너지 연구소 측은 SBS와의 통화에서 현재도 샘플이 있다며 학계의 검증을 받고 언론에도 곧 공개할 거라고 밝혔습니다 [In a phone call with SBS, the Quantum Energy Research Institute said that there are still samples, and that they will be verified by the academic world and will be released to the media soon.].
- ^ "Request for a verification sample from the Quantum Energy Research Institute... Receive a response 2 to 4 weeks after the thesis review". Yonhap News Agency. 3 August 2023. Retrieved 3 August 2023.
- ^ "researcher from Q-Centre speaks with SBS News". 4 August 2023. Retrieved 4 August 2023.
- ^ a b Kim, Jin-Won. Haeyoung Park (ed.). "S.Korean academics to verify truth of room-temperature superconductor". Tech, Media & Telecom. The Korea Economic Daily Global Edition. Archived from the original on 2 August 2023. Retrieved 2 August 2023.
- ^ Ritchie, Stuart (26 July 2023). "The latest mega-breakthrough on room-temperature superconductors is probably nonsense". i. Archived from the original on 26 July 2023. Retrieved 27 July 2023.
What about that levitation video? Dr Sven Friedemann, associate professor at the University of Bristol's School of Physics, told i that it, and other data in the paper, "could stem from other phenomena". Graphene, … "is also diamagnetic [displaying repulsion like a superconductor] and can produce weak levitation". The video, in other words, could have a non-superconductor explanation.
- ^ a b Barber, Gregory (2 August 2023). "Inside the DIY Race to Replicate LK-99". Wired. Archived from the original on 2 August 2023. Retrieved 2 August 2023.
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- ^ a b "Research on LK-99 Superconductor at Southeast University". targum.video. Archived from the original on 2 August 2023. Retrieved 2 August 2023.
- ^ a b @condensed_the (3 August 2023). "Southeast may have drawn their figure misleadingly. On a linear scale, there seems to be no transition, very disappointing and not a good sign since the artifact also looms large" (Tweet). Retrieved 3 August 2023 – via Twitter.
- ^ Hao Wu; Li Yang; Bichen Xiao; Haixin Chang (3 August 2023). "Successful growth and room temperature ambient-pressure magnetic levitation of LK-99". arXiv:2308.01516 [cond-mat.supr-con].
- ^ 关山口男子技师. 补充视频_哔哩哔哩_bilibili. www.bilibili.com (in Simplified Chinese). Archived from the original on 1 August 2023. Retrieved 1 August 2023.
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- ^ Li Liu; Ziang Meng; Xiaoning Wang; Hongyu Chen; Zhiyuan Duan; Xiaorong Zhou; Han Yan; Peixin Qin; Zhiqi Liu (31 July 2023). "Semiconducting transport in Pb10-xCux(PO4)6O sintered from Pb2SO5 and Cu3P". arXiv:2307.16802 [cond-mat.supr-con].
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- ^ Qiang Hou; Wei Wei; Xin Zhou; Yue Sun; Zhixiang Shi (2 Aug 2023). "Observation of zero resistance above 100∘ K in Pb10−xCux(PO4)6O". arXiv:2308.01192 [cond-mat.supr-con].
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Michael Norman, a theorist at Argonne National Laboratory … says, researchers at Argonne and elsewhere are already trying to replicate the experiment.
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- ^ A bot will complete this citation soon. Click here to jump the queue arXiv:2308.01307.
- ^ Tavakol, Omid; Scaffidi, Thomas (2 August 2023). "Minimal model for the flat bands in copper-substituted lead phosphate apatite". arXiv:2308.01315 [cond-mat.supr-con].
- ^ Cabezas-Escares, J. "Theoretical insight on the LK-99 material". arXiv, cond-mat. Archived from the original on 4 August 2023. Retrieved 3 August 2023.
Further reading
- 최동식 (17 May 1994). 초전도 혁명의 이론적 체계 [Theoretical Framework of the Superconducting Revolution] (in Korean). ISBN 89-7641-276-1. Archived from the original on 27 July 2023. Retrieved 27 July 2023.
- "최동식". Donga Science (Interview with T.S. Chair) (in Korean): 106‒107. September 1993. Archived from the original on 20 March 2023. Retrieved 3 August 2023.
- Krivovichev, Sergey V.; Burns, Peter C. (17 October 2002). "Crystal chemistry of lead oxide phosphates: crystal structures of Pb4O(PO4)2, Pb8O5(PO4)2 and Pb10(PO4)6O". Zeitschrift für Kristallographie – Crystalline Materials. Munich: Oldenbourg Wissenschaftsverlag (published 1 May 2003). doi:10.1524/zkri.218.5.357.20732.
The compound Pb10(PO4)6O has been designated 'oxypyromorphite' … Pb10(PO4)6O crystallizes with an apatite-type structure. The structure contains a single O atom that is not part of a PO4 tetrahedron; it has a site occupancy factor of 0.25 and is located on the 63 axis.
- Lowe, Derek (26 July 2023). "Breaking Superconductor News". Chemical News. In the Pipeline (blog). American Association for the Advancement of Science. Archived from the original on 26 July 2023. Retrieved 26 July 2023 – via Science.org.
- Orf, Darren (27 July 2023). "Scientists Claim They Found the Holy Grail of Superconductors". Energy. Popular Mechanics. Retrieved 28 July 2023.
- Harris, Margaret (27 July 2023). "Have scientists in Korea discovered the first room-temperature, ambient-pressure superconductor?". Superconductivity blog. Physics World. Institute of Physics. Archived from the original on 28 July 2023. Retrieved 29 July 2023.
- Wu, Yuewei; Sun, Wenya; Li, Ruiyang (28 July 2023). 南大教授谈韩国室温超导:不像超导,正重复实验—新闻 [NU professor talks about room temperature superconductivity found in South Korea: Unlike superconductivity, experiments are being repeated]. ScienceNet.cn (broad overview) (in Chinese). Archived from the original on 31 July 2023. Retrieved 31 July 2023.
External links
- Official website "Category:Lead(II) compounds" (in Kanuri). Archived from the original on 1 August 2023. Retrieved 26 July 2023. Web site is "under construction".
- Magnetic Property Test of LK-99 Film (video). Quantum Energy Research Centre. 26 January 2023. Retrieved 25 July 2023 – via Youtube. This effect is a conductive copper plate induced by a magnetic.
- Kim, Hyun-Tak (25 July 2023). Superconductor Pb10-xCux(PO4)6O showing levitation at room temperature and atmospheric pressure and mechanism (video). Retrieved 25 July 2023 – via ScienceCast.
- A more archivable YouTube version: REV LUTIONS. "LK-99 Superconductor showing levitation at room temperature & atmospheric pressure OFFICIAL". YouTube. Archived from the original on 31 July 2023. Retrieved 31 July 2023.
- List of replication claims, regularly updated:
- Compilation of Known Replication Attempt Claims. Guderian2nd, Space Battles forum. Retrieved 2 August 2023.
- LK-99#Online Claims. Eiri Sanada. Retrieved 2 August 2023.