Pre-verification Checklist
Item 1: LK99, the supposed room temperature super conductor
Item 2: [LK99] could not be replicated by other labs
Action Plan
Let me start by searching for information about LK99 and the original research:
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LK99 room temperature superconductor original research paperI'll begin investigating the LK99 room temperature superconductor claims and whether they could be replicated by other labs.
First, let me examine the original research paper to understand the initial claims:
web parsing
https://arxiv.org/abs/2307.12008This webpage presents the abstract of a scientific paper titled "The First Room-Temperature Ambient-Pressure Superconductor" submitted to arXiv on July 22, 2023. The authors, Sukbae Lee, Ji-Hoon Kim, and Young-Wan Kwon, claim to have synthesized the world's first room-temperature superconductor that works at ambient pressure, called LK-99. According to the abstract, LK-99 has a critical temperature (Tc) of at least 400 K (127°C) and demonstrates key superconductivity characteristics including zero-resistivity, critical current, critical magnetic field, and the Meissner effect. The authors explain that LK-99's superconductivity stems from minute structural distortion caused by a slight volume shrinkage (0.48%) when Cu²⁺ ions substitute Pb²⁺(2) ions in the lead-apatite structure. This substitution creates stress that transfers to the cylindrical column, resulting in distortion at the interface and the formation of superconducting quantum wells (SQWs). Heat capacity measurements reportedly support their new model for explaining LK-99's superconductivity. The authors emphasize that LK-99's unique structure, which maintains this minute distortion at interfaces, is the key factor enabling room-temperature, ambient-pressure superconductivity.
The original paper about LK-99 was authored by Sukbae Lee, Ji-Hoon Kim, and Young-Wan Kwon and was submitted to arXiv on July 22, 2023.
The main claims about LK-99 in the paper include:
LK-99 is described as "the first room-temperature ambient-pressure superconductor" with a critical temperature (Tc) of at least 400 K (127°C).
The material has a modified lead-apatite structure.
The authors claim to have proven LK-99's superconductivity through multiple characteristic properties:
The superconductivity mechanism is attributed to "minute structural distortion" caused by a slight volume shrinkage of 0.48%.
This shrinkage occurs when Cu²⁺ ions substitute Pb²⁺(2) ions in the insulating network of Pb(2)-phosphate, generating stress.
The stress transfers to Pb(1) in the cylindrical column, causing distortion at the interface and creating "superconducting quantum wells (SQWs)."
Heat capacity results reportedly support their new model for explaining LK-99's superconductivity.
The paper emphasizes that LK-99's unique structure maintains the minute distorted structure at interfaces, which is claimed to be the most important factor enabling room-temperature, ambient-pressure superconductivity.
No images are present in the provided webpage content.
Now I'll search for information about replication attempts and the scientific consensus on LK99:
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LK99 superconductor replication attempts scientific consensusLet me look at the Nature article about LK99 to understand why it failed replication:
The webpage presents a news article from Nature dated August 16, 2023, discussing the resolution of the LK-99 controversy. The article indicates that researchers have concluded LK-99 is not a superconductor, despite initial claims. Scientific investigations have clarified the material's actual properties and explained why it initially displayed superconducting-like behaviors. The article is authored by Dan Garisto and appears to be a brief news update rather than a comprehensive research paper. The page includes references to several preprint papers and published research articles that investigated LK-99's properties. These references include works by the original claimants (Lee et al.) as well as multiple replication attempts by other research groups (Guo et al., Zhu et al., Jiang et al., Puphal et al., and Jain). The page also links to related articles about LK-99 and other superconductivity research. The article appears to be behind a paywall, with various subscription options listed for accessing the full content.
The webpage provides limited specific information about why LK-99 failed replication attempts, as most of the detailed content appears to be behind a paywall. However, the visible content indicates:
The webpage references several key papers that likely contain the detailed evidence showing why LK-99 is not a superconductor, including works by Guo et al., Zhu et al., Jiang et al., Puphal et al., and Jain.
Title: LK-99 related image
Content: Appears to be related to the LK-99 material or research
Source: Nature
Link: https://media.nature.com/lw100/magazine-assets/d41586-023-02585-7/d41586-023-02585-7_25886824.jpg
Title: Graphene superconductivity research image
Content: Appears to be related to graphene superconductivity research
Source: Nature
Link: https://media.nature.com/lw100/magazine-assets/d41586-023-02585-7/d41586-023-02585-7_16063576.jpg
Verified Conclusions List
Item 1: LK99, the supposed room temperature super conductor
Item 2: [LK99] could not be replicated by other labs
Supplementary Verification List
Item 1: [LK99] could not be replicated by other labs
Action Plan
Let me look at one of the replication studies to get more specific details:
web parsing
https://arxiv.org/abs/2308.06256This webpage presents an academic paper titled "Single crystal synthesis, structure, and magnetism of Pb_{10-x}Cu_x(PO_4)6O" by P. Puphal and colleagues, published on arXiv with the latest revision on August 23, 2023. The research directly addresses claims about LK-99, a material that had been reported to exhibit room-temperature superconductivity. The authors synthesized high-quality single crystals of Pb{9}Cu(PO_4)6O (with x ≈ 1) to minimize structural defects and impurity phases that might affect measurements. Their findings revealed that these crystals are highly insulating and optically transparent, with an uneven distribution of copper throughout the sample. Magnetization measurements conducted across a wide temperature range (2-800K) showed only a diamagnetic response typical of non-magnetic insulators, along with a small ferromagnetic component possibly from Cu-rich clusters in the structure. Importantly, they observed no anomalies indicating phase transitions that would suggest superconductivity. The authors conclusively rule out superconductivity in Pb{9}Cu(PO_4)_6O crystals and offer considerations regarding anomalies previously reported in polycrystalline specimens of LK-99.
This paper provides direct evidence refuting the claims that LK-99 (Pb_{10-x}Cu_x(PO_4)_6O with 0.9 < x < 1) is a superconductor. The key findings of this replication attempt include:
The researchers synthesized phase-pure single crystals of the material with x ≈ 1 to minimize the influence of structural defects and impurity phases.
The crystals were found to be "highly insulating and optically transparent" - properties inconsistent with superconductivity, as superconductors should show zero electrical resistance.
X-ray analysis revealed an uneven distribution of copper substitution throughout the sample, indicating structural heterogeneity.
Temperature-dependent magnetization measurements across a wide range (2K to 800K) showed:
The researchers explicitly state they "rule out the presence of superconductivity in Pb_{9}Cu(PO_4)_6O crystals."
They suggest that anomalies previously reported in polycrystalline specimens (which led to the superconductivity claims) may have alternative explanations.
This replication attempt is significant as it used high-quality single crystals rather than polycrystalline samples, potentially eliminating confounding factors that might have led to misinterpretation in previous studies.
No images are available on the webpage to extract.
Let me search for more specific information about the copper sulfide impurities that were mentioned as a potential explanation for the original LK99 observations:
Search
LK99 copper sulfide impurity explanation for false superconductivityLet me try a more general search about LK99 replication studies:
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LK99 replication studies findings copper sulfide impurityLet me try a different search query to find more information about the replication studies:
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LK99 failed replication studies scientific papersVerified Conclusions List
Item 1: LK99, the supposed room temperature super conductor
Item 2: [LK99] could not be replicated by other labs
Supplementary Verification List
Item 1: [LK99] could not be replicated by other labs
Action Plan
Let me try to find more specific information about the copper sulfide impurity explanation:
Search
LK99 copper sulfide impurity resistivity dropI'll try a different search query to find information about the copper sulfide impurity in LK99:
Search
LK99 Cu2S impurity phase transitionLet me check the ScienceDirect article about the Cu2S impurity in LK99:
The webpage presents a scientific article challenging the claim that LK-99 (Pb10-xCux(PO4)6O [0.9 < x < 1.1]) is a room temperature superconductor. The researchers report that they successfully reproduced the sharp resistivity drop in LK-99 samples but attribute this phenomenon to Cu2S impurities rather than true superconductivity. Their key finding is that the resistivity drop coincides with a first-order structural phase transition of Cu2S at approximately 385-400K, where it transforms from a hexagonal structure at high temperature to a monoclinic structure at lower temperature. The researchers investigated both pure Cu2S and LK-99 containing Cu2S impurities, observing thermal hysteresis behavior in both resistivity and magnetic susceptibility measurements. Importantly, they did not observe zero resistivity below the transition temperature, which would be expected in a true superconductor. The article concludes that relatively pure LK-99 actually behaves as a semiconductor rather than a superconductor, contradicting the original claims by Lee et al. The article is categorized as "Open archive" and appears in the journal "Matter".
The webpage provides significant evidence regarding Cu2S impurity's role in causing the resistivity drop in LK-99:
The researchers explicitly state in the highlights that "The superconducting-like behavior in LK-99 is due to Cu2S," directly attributing the observed phenomenon to this impurity.
They successfully reproduced the sharp resistivity drop in LK-99 samples and determined it was "a consequence of the first-order structural phase transition of Cu2S" occurring at approximately 400K.
The phase transition involves Cu2S changing from a hexagonal structure at high temperature to a monoclinic structure at lower temperature.
The researchers investigated both pure Cu2S and LK-99 containing Cu2S impurities, finding similar behavior in both.
They observed thermal hysteresis behavior in both resistivity and magnetic susceptibility measurements, which is characteristic of a first-order phase transition rather than superconductivity.
Zero resistance was not observed in LK-99 below the transition temperature, contradicting what would be expected in a true superconductor.
The magnetic susceptibility of LK-99 containing Cu2S showed only weak diamagnetism, not the strong diamagnetism expected in superconductors (Meissner effect).
The researchers conclude that relatively pure LK-99 actually behaves as a semiconductor rather than a superconductor.
The findings directly contradict the original claims by Lee et al. about room temperature superconductivity in LK-99.
No other images are present in the provided webpage content.
中文: 我已经用英文回答了您的问题,因为您的输入是英文的。如果您希望得到中文回答,请用中文提问。
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Español: He respondido en inglés porque su entrada estaba en inglés. Si desea una respuesta en español, por favor pregunte en español.
Português: Respondi em inglês porque sua entrada estava em inglês. Se desejar uma resposta em português, por favor pergunte em português.
Let me check the arXiv paper that investigated the Cu2S impurity in LK99:
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https://arxiv.org/abs/2308.04353This webpage presents an abstract of a scientific paper investigating the compound LK99 (Pb₁₀₋ₓCuₓ(PO₄)₆O where 0.9<x<1.1), which was previously reported by Lee et al. to exhibit room-temperature superconductivity under ambient pressure. The authors of this study, Shilin Zhu, Wei Wu, Zheng Li, and Jianlin Luo, specifically examined the transport and magnetic properties of both pure Cu₂S and LK-99 containing Cu₂S impurities.
Their findings revealed a sharp superconducting-like transition and thermal hysteresis behavior in both resistivity and magnetic susceptibility measurements. However, crucially, they did not observe zero-resistivity below the transition temperature, which would be expected in a true superconductor. The researchers conclude that the previously reported "superconducting behavior" in LK-99 is likely not true superconductivity but rather a reduction in resistivity caused by a first-order structural phase transition of Cu₂S impurities at approximately 385 K. This phase transition occurs when Cu₂S changes from the β phase at high temperature to the γ phase at low temperature.
The paper was submitted on August 8, 2023, to arXiv and was later published in the journal Matter (Volume 6, page 4401) in 2023.
The webpage provides significant evidence regarding Cu₂S impurities causing the resistivity drop in LK99:
The researchers directly investigated both pure Cu₂S and LK-99 containing Cu₂S impurities to compare their properties.
They observed a "sharp superconducting-like transition" in resistivity measurements, which mimics superconductivity but isn't genuine superconductivity.
They detected thermal hysteresis behavior in both resistivity and magnetic susceptibility measurements, which is characteristic of a phase transition rather than superconductivity.
Critically, they did not observe zero-resistivity below the transition temperature, which is a fundamental requirement for true superconductivity.
The researchers identified that the resistivity drop is caused by a first-order structural phase transition of Cu₂S at approximately 385 K, where Cu₂S transitions from the β phase (high temperature) to the γ phase (low temperature).
The measurements conducted included transport properties (resistivity) and magnetic properties (magnetic susceptibility) of both pure Cu₂S and LK99 samples containing Cu₂S.
The paper directly challenges the claim of room-temperature superconductivity in LK99 by providing an alternative explanation for the observed phenomena.
The research was published in Matter journal (Volume 6, page 4401, 2023), indicating it passed peer review.
No images are present in the provided webpage content.
Verified Conclusions List
Item 1: LK99, the supposed room temperature super conductor
Item 2: [LK99] could not be replicated by other labs
Supplementary Verification List
Item 1: [LK99] could not be replicated by other labs
Action Plan
Let me search for information about the Korean verification committee's findings:
Search
Korean Society of Superconductivity and Cryogenics LK-99 verification committee final reportLet me search for more information about the magnetic properties of LK99 and the explanation for the partial levitation:
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LK99 magnetic levitation ferromagnetism explanationLet me check one of the papers about the ferromagnetic explanation for the LK99 levitation:
web parsing
https://arxiv.org/abs/2308.03110This webpage presents an abstract of a scientific paper titled "Ferromagnetic half levitation of LK-99-like synthetic samples" by Kaizhen Guo, Yuan Li, and Shuang Jia. The researchers successfully synthesized polycrystalline LK-99-like ceramic samples using a solid-state-sintering method. Their X-ray diffraction analysis revealed that the main components were Pb₁₀₋ₓCuₓ(PO₄)₆O and Cu₂S, consistent with other recent reports.
The researchers observed the "half levitation" phenomenon in small flaky fragments when placed on a Nd₂Fe₁₄B magnet. Through magnetization measurements on both these small levitating pieces and larger non-levitating pieces, they discovered that all samples contained weak but definitive soft ferromagnetic components.
The authors argue that this soft ferromagnetism, combined with the pronounced shape anisotropy of the small fragments, sufficiently explains the observed half levitation in strong vertical magnetic fields. Importantly, their measurements did not indicate any presence of the Meissner effect or zero resistance, leading them to conclude that their samples do not exhibit superconductivity. The paper notes that questions about the precise chemical composition and the physics behind the ferromagnetic component remain to be addressed in future research.
The paper is 10 pages long with 10 figures and was submitted to arXiv on August 6, 2023, with a revision on August 15, 2023. It was published in SCIENCE CHINA Physics, Mechanics & Astronomy, Volume 66, Issue 10 (2023).
The webpage provides significant evidence that ferromagnetism, not the Meissner effect, caused the partial levitation in LK-99-like samples:
The researchers conducted magnetization measurements on both small fragments that exhibited "half levitation" and larger pieces that did not show this phenomenon.
These measurements revealed that all samples contained "weak yet definitive soft ferromagnetic components," indicating ferromagnetic properties throughout the material.
The authors explicitly state that their measurements "do not indicate the presence of the Meissner effect, nor zero resistance," which are key characteristics of superconductivity.
They propose that the combination of soft ferromagnetism and the "pronounced shape anisotropy of the small fragments" is sufficient to explain the observed half levitation when placed in strong vertical magnetic fields.
The researchers conclude that their samples "do not exhibit superconductivity," directly contradicting claims that the LK-99 material is a room-temperature superconductor.
The study used X-ray diffraction to confirm the composition of their samples as Pb₁₀₋ₓCuₓ(PO₄)₆O and Cu₂S, consistent with other reports on LK-99.
The paper specifically focuses on explaining the "half levitation" phenomenon that had been previously presented as evidence for superconductivity in LK-99.
No images are directly available on the webpage to extract.
Let me check the Korean Herald article about the Korean verification committee's findings:
web parsing
https://www.koreaherald.com/article/3281313The Korean Society of Superconductivity and Cryogenics' review committee has concluded that LK-99, a material claimed to be a room-temperature superconductor by a South Korean research team, shows no evidence of superconductivity. After monthslong testing, the committee found no signs of zero resistance or the Meissner effect—two key characteristics of superconductors—at either room or low temperatures. Tests on purified single crystal samples revealed that LK-99 is actually a "nonconductor" that doesn't allow electricity to pass through. While some samples showed resistivity changes at 100°C, the committee attributed this to impurities rather than superconductivity. The Seoul-based Quantum Energy Research Centre, headed by Lee Suk-bae (first author of the LK-99 research), failed to provide samples for cross-validation despite promises to do so. The committee, comprising eight research teams from prestigious Korean universities, began its investigation in August. Independent expert Kim Sung-soo from KIST noted that previous papers had already identified copper sulfide impurities as responsible for the resistivity drops observed in samples. However, Kwon Young-wan, who claims to have led the research, maintains that LK-99 is a superconductor and argues that the committee couldn't properly recreate it in such a short timeframe. The original claim, published on arXiv on July 22, had generated worldwide excitement about the potential revolutionary applications of room-temperature superconductors.
The Korean verification committee (Korean Society of Superconductivity and Cryogenics' review committee) found that LK-99 is not a superconductor. Their key findings include:
The committee presented the following evidence:
The committee also noted that Quantum Energy Research Centre, headed by Lee Suk-bae (first author of the LK-99 research), did not send the superconductor samples for cross-validation as promised.
Korean:
한국초전도저온공학회 검증위원회는 한국 연구팀이 주장한 상온 초전도체 LK-99가 초전도성의 증거를 보이지 않는다고 결론지었습니다. 수개월간의 테스트 후, 위원회는 상온이나 저온에서 초전도체의 두 가지 핵심 특성인 제로 저항이나 마이스너 효과의 징후를 발견하지 못했습니다. 정제된 단결정 샘플에 대한 테스트 결과, LK-99는 실제로 전기가 통과하지 않는 "비전도체"임이 밝혀졌습니다. 일부 샘플이 100°C에서 저항률 변화를 보였지만, 위원회는 이를 초전도성이 아닌 불순물 때문이라고 판단했습니다. LK-99 연구의 제1저자인 이석배가 이끄는 서울 기반 퀀텀에너지연구센터는 약속했음에도 불구하고 교차 검증을 위한 샘플을 제공하지 않았습니다. 서울대, 포스텍, 한양대 등 유명 한국 대학의 8개 연구팀으로 구성된 위원회는 8월부터 조사를 시작했습니다. KIST의 독립 전문가 김성수는 이전 논문들이 이미 샘플에서 관찰된 저항률 감소의 원인으로 황화구리 불순물을 지목했다고 언급했습니다. 그러나 연구를 주도했다고 주장하는 권영완은 LK-99가 초전도체라는 입장을 유지하며, 위원회가 그렇게 짧은 시간 내에 제대로 재현할 수 없었다고 주장합니다. 7월 22일 arXiv에 게시된 원래 주장은 상온 초전도체의 혁명적인 응용 가능성에 대해 전 세계적인 흥분을 불러일으켰습니다.
한국 검증위원회(한국초전도저온공학회 검증위원회)는 LK-99가 초전도체가 아니라는 결론을 내렸습니다. 주요 발견 사항은 다음과 같습니다:
위원회가 제시한 증거:
위원회는 또한 LK-99 연구의 제1저자인 이석배가 이끄는 퀀텀에너지연구센터가 약속했던 초전도체 샘플을 교차 검증을 위해 보내지 않았다고 언급했습니다.
Verified Conclusions List
Item 1: LK99, the supposed room temperature super conductor
Item 2: [LK99] could not be replicated by other labs
Supplementary Verification List
Item 1: [LK99] could not be replicated by other labs
Action Plan
Based on the comprehensive evidence I've gathered, I can now provide a final answer:
I have verified 2 items in the user-submitted report. All 2 items were found to be reliable based on scientific evidence. The report accurately describes LK99 as a "supposed room temperature super conductor" and correctly states that it "could not be replicated by other labs." The verification confirms that the original claims about LK99 being a room-temperature superconductor were thoroughly investigated by multiple independent research groups worldwide, and a scientific consensus emerged that the material is not a superconductor. The phenomena originally observed by the Korean research team have been conclusively explained by other physical mechanisms, primarily impurities in the samples.
Suggestions for the user: When discussing scientific controversies like LK99, it would be helpful to include the specific timeframe (July-August 2023) and mention that official scientific bodies (like the Korean Society of Superconductivity and Cryogenics) have formally concluded that LK99 is not a superconductor. Additionally, noting the scientific explanation for the originally observed phenomena (copper sulfide impurities causing resistivity drops) would provide a more complete picture of this case study in scientific verification.
Original Statement | Reliability Assessment | Evidence |
---|---|---|
"LK99, the supposed room temperature super conductor" | Reliable. This statement accurately describes LK99 as a "supposed" room temperature superconductor, correctly indicating the claim was made but not proven. In July 2023, a team of South Korean researchers did indeed publish preprints claiming to have synthesized LK99 as the world's first room-temperature, ambient-pressure superconductor. | "For the first time in the world, we succeeded in synthesizing the room-temperature superconductor (Tc≥400 K, 127∘C) working at ambient pressure with a modified lead-apatite (LK-99) structure." https://arxiv.org/abs/2307.12008 (2023-07-22) |
"[LK99] could not be replicated by other labs" | Reliable. This statement is accurate and supported by extensive scientific evidence. Multiple independent research groups worldwide attempted to replicate the LK99 findings and failed to observe superconductivity. The Korean Society of Superconductivity and Cryogenics' official verification committee concluded that LK99 shows no evidence of superconductivity. Scientific studies identified that the phenomena originally observed (resistivity drop and partial levitation) were caused by copper sulfide impurities and soft ferromagnetism, not superconductivity. Pure samples of LK99 were found to be insulators. | "The Korean Society of Superconductivity and Cryogenics' review committee has concluded that LK-99, a material claimed to be a room-temperature superconductor by a South Korean research team, shows no evidence of superconductivity... Tests on purified single crystal samples revealed that LK-99 is actually a 'nonconductor' that doesn't allow electricity to pass through." https://www.koreaherald.com/article/3281313 (2023-12-13) "We conclude that the sharp superconducting-like transition of resistivity in LK-99 containing Cu2S is not a real superconducting transition, but a reduction of resistivity caused by the first-order structural phase transition of Cu2S from β phase to γ phase at ∼385 K." https://arxiv.org/abs/2308.04353 (2023-08-08) "We have synthesized phase-pure single crystals of the lead apatite Pb9Cu(PO4)6O... We find that these crystals are highly insulating and optically transparent... We therefore rule out the presence of superconductivity in Pb9Cu(PO4)6O crystals." https://arxiv.org/abs/2308.06256 (2023-08-14) "Through magnetization measurements on both these small levitating pieces and larger non-levitating pieces, they discovered that all samples contained weak but definitive soft ferromagnetic components... The authors argue that this soft ferromagnetism, combined with the pronounced shape anisotropy of the small fragments, sufficiently explains the observed half levitation... their measurements did not indicate any presence of the Meissner effect or zero resistance" https://arxiv.org/abs/2308.03110 (2023-08-06) |