National Lab (LBNL) results support LK-99 as a room-temperature ambient-pressure superconductor. Simulations published 1 hour ago on arxiv support LK-99 as the holy grail of modern material science and applied physics. (arxiv.org/abs/2307.16892) Here''s the plain-english explanation: - The simulations modeled what the original Korean authors proposed was happening to their material - where copper atoms were percolating into a crystal structure and replacing lead atoms, causing the crystal to strain slightly and contract by 0.5%. This unique structure was proposed to allow this amazing property. - @sineatrix from Lawrence Berkeley National Lab simulated this using heavy-duty compute power from the Department of Energy, and looked to see what would happen to the ''electronic structure'' of this material, meaning, what are the available conduction pathways in the material. - It turns out that there are conduction pathways for electrons that are in just the right conditions and places that would enable them to ''superconduct''. More specifically, they were close to the ''Fermi Surface'' which is like the sea-level of electrical energy, as in ''0 ft above sea-level.'' It''s believed currently that the more conduction pathways close to the Fermi surface, the higher the temperature you can superconduct at (An analogy might be how its easier for planes to fly close to the surface of the ocean due to the ''ground effect'' that gives them more lift.) This plot in particular shows the ''bands'', or electron pathways, crossing above and below the Fermi surface. - Lastly, these interesting conduction pathways only form when the copper atom percolates into the less likely location in the crystal lattice, or the ''higher energy'' binding site. This means the material would be difficult to synthesize since only a small fraction of crystal gets its copper in just the right location. This is insanely bullish for humanity.
美国凝聚态理论中心的最新表态: 1)有几个小组已经制造出了LK99,但这些复制品意义不大,因为 Pb/Cu/P/O 合金很脆弱,而且可能具有不同的形态/性质。唯一相关的问题是:它会超导吗? 这些问题还没有人解决过,在报告超导性之前,其他实验室复制LK99 的兴奋情绪是错误的。独立合成LK99是一个次要但必要的步骤。 2)不出所料,已经有带状结构计算的报道,相关波段在 1000K 范围内是 "平坦的"--一篇论文非常详细,提供了 LDA+ U 结果,发现 Hubbard-U 拓宽了相关波段!对于这种平坦波段系统,LDA 类型的成套计算作用有限,但了解 LDA 波段结构也是理解物理学的一小步,但却是必要的一步。 平带并不意味着超导性,平带通常会导致磁不稳定性。 3)发布的理论论文中没有一篇进行了任何超导计算(例如估计el-ph耦合和BCS T_c),因此这些论文对LK-99的超导特性一无所知,更不用说室温超导了。 4)我们没有看到任何可以改变我们最初预测的东西。 其中一篇原始论文(有 6 位作者)以修订版的形式重新发布,但改动似乎微乎其微,这篇论文仍然晦涩难懂,难以令人信服(但不一定不正确)。我们必须等待外部的 超导数据。 Condensed Matter Theory Center @condensed_the CMTC has received SO MANY requests to provide an update on LK99 that we are breaking our 'sign-off' since our tweets are only for the purpose of precise scientific outreach from our critical perspective, So, here we go...
韩国LK-99 提供了超导材料的lead,在美国理论证实后,每个国家都将投入更多的资源,不断完善工艺制备技术,相信不远的未来会有实质性的突破。
LK-99室温超导的最新进展汇总如下:
1.韩国科研团队历经30 年的努力,终于在偶然的实验条件下实现了重大突破,但内部利益冲突导致预印办论文过早发布,部分核心细节(即偶然的实验条件)并未详细披露。
2.(第一次制备)华中科技大学的研究团队已经部分验证了韩国科研团队的发现,但由于合成物纯度等问题,尚无法完全复制实验,目前正在改进研究方法。
3. 芳伦斯伯克利国家实验室(LBNL)的研究员使用超级计算机模拟,验证了韩国论文在理论上的可行性,非常确信LK-99材料的超导特性,并期待通过此类模拟实验找到更多类似的,合成过程更简单的超导材料。
4. 然而,伯克利的理论模拟同时也揭示了这种化合物的合成过程要比预想中的难,特别是需要铜原子浸透到晶体格子中较不可能出现的位置,这就导致了只有一小部分晶体能在正确的位置得到铜。
5.(第二次制备)华中科技大学已经成功复现了LK-99的迈斯纳效应 (Meissner effect)。在常海欣教授的指导下,武浩博士后、杨丽博士生成功合成了可以磁悬浮的LK-99晶体,悬浮角度比Sukbae Lee 等人获得的样品还要大,这预示着有望实现真正的无接触超导磁悬浮。
总的来说,虽然现在还面临一些挑战,但是LK-99超导材料的研究已经取得了重大进展,展现了它在室温下的超导可能性。这项科研成果无疑开启了一个新的研究方向,引领了科研工作者进一步探索和发现更多的室温超导材料。
https://arxiv.org/pdf/2307.16040.pdf
Simulations published 1 hour ago on arxiv support LK-99 as the holy grail of modern material science and applied physics. (arxiv.org/abs/2307.16892)
Here''s the plain-english explanation: - The simulations modeled what the original Korean authors proposed was happening to their material - where copper atoms were percolating into a crystal structure and replacing lead atoms, causing the crystal to strain slightly and contract by 0.5%. This unique structure was proposed to allow this amazing property.
- @sineatrix from Lawrence Berkeley National Lab simulated this using heavy-duty compute power from the Department of Energy, and looked to see what would happen to the ''electronic structure'' of this material, meaning, what are the available conduction pathways in the material.
- It turns out that there are conduction pathways for electrons that are in just the right conditions and places that would enable them to ''superconduct''. More specifically, they were close to the ''Fermi Surface'' which is like the sea-level of electrical energy, as in ''0 ft above sea-level.'' It''s believed currently that the more conduction pathways close to the Fermi surface, the higher the temperature you can superconduct at (An analogy might be how its easier for planes to fly close to the surface of the ocean due to the ''ground effect'' that gives them more lift.)
This plot in particular shows the ''bands'', or electron pathways, crossing above and below the Fermi surface.
- Lastly, these interesting conduction pathways only form when the copper atom percolates into the less likely location in the crystal lattice, or the ''higher energy'' binding site. This means the material would be difficult to synthesize since only a small fraction of crystal gets its copper in just the right location.
This is insanely bullish for humanity.
高铁可以达到3000公里每小时。飞机将会在中国被淘汰。
如果高铁能够凭借这个技术更快,那么飞机难道不能更快吗?否则怎么去火星呢
核磁共振要降价了
这是第一性计算,不是实验证实
长材料(这块儿,能不能叫“实验流程”,是另一个问题)另说,但同样的材料,测量结果不会千差万别的。。。
1)有几个小组已经制造出了LK99,但这些复制品意义不大,因为 Pb/Cu/P/O 合金很脆弱,而且可能具有不同的形态/性质。唯一相关的问题是:它会超导吗? 这些问题还没有人解决过,在报告超导性之前,其他实验室复制LK99 的兴奋情绪是错误的。独立合成LK99是一个次要但必要的步骤。 2)不出所料,已经有带状结构计算的报道,相关波段在 1000K 范围内是 "平坦的"--一篇论文非常详细,提供了 LDA+ U 结果,发现 Hubbard-U 拓宽了相关波段!对于这种平坦波段系统,LDA 类型的成套计算作用有限,但了解 LDA 波段结构也是理解物理学的一小步,但却是必要的一步。 平带并不意味着超导性,平带通常会导致磁不稳定性。 3)发布的理论论文中没有一篇进行了任何超导计算(例如估计el-ph耦合和BCS T_c),因此这些论文对LK-99的超导特性一无所知,更不用说室温超导了。 4)我们没有看到任何可以改变我们最初预测的东西。 其中一篇原始论文(有 6 位作者)以修订版的形式重新发布,但改动似乎微乎其微,这篇论文仍然晦涩难懂,难以令人信服(但不一定不正确)。我们必须等待外部的 超导数据。
Condensed Matter Theory Center @condensed_the
CMTC has received SO MANY requests to provide an update on LK99 that we are breaking our 'sign-off' since our tweets are only for the purpose of precise scientific outreach from our critical perspective, So, here we go...
磁悬浮列车可以在真空管中无阻力运行,飞机不行
现在大部分人没有怀疑原作者作假,也就是说,不怀疑他们的结果是否能被重复(这与之前那位印度同学的nature文章是不同的)。
现在问题的焦点是,这些结果(包括国内那些组重复出来的结果),是不是足够说明这材料超导?答案是,不能。注意,不是说“肯定不超导”,而是说,现在这些结果不足以说明此材料超导。
"出生率持续下降,人民水深火热,傻总统天天到处搞事,前段时间发大水" 笑了。
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