UPDATE: Hyun Tak Kim has put out news slides that describes a semiconductor and superconductor phase for LK99. He quoted his own paper on VO2 to explain that most researchers did not understand the difference between MIT and MST (MIT, metal to insulator transition: after cooling down, the resistivity jump → becomes very large; MST, transition from metal to superconductor: resistivity jump after cooling down → becomes very small).
1. Princeton – Magnetic Materials, Not Superconductors with Arxiv 1 preprint of announcement from 2 days ago.
2. University of PUC-Rio, Brazil – “Analyzed Model (Theoretical Calculations)”. Arxiv 2.
Berry curvature and quantum metric in copper-substituted lead phosphate apatite (Wei Chen)
Be it superconducting or not, we show that the normal state of this material has peculiar quantum geometrical properties that may be related to the magnetism and the mechanism for flat band superconductivity. Based on a recently proposed spinless two-band tight-binding model for the Pb-Cu hexagonal lattice subset of the crystalline structure, which qualitatively captures the two flat bands in the band structure, we elaborate the highly anisotropic Berry curvature and quantum metric in the regions of Brillouin zone where one flat band is above and the other below the Fermi surface. In these regions, the Berry curvature has a pattern in the planar momentum that remains unchanged along the out-of-plane momentum. Moreover, the net orbital magnetization contributed from the Berry curvature is zero, signifying that the magnetism in this material should come from other sources. The quantum metric has a similar momentum dependence, and its two planar components are found to be roughly the same but the out-of-plane component vanishes, hinting that the superfluid stiffness of the flat band superconductivity, shall it occur, may be quite anisotropic.
3. Peking University – “One Theoretical Computing Paper”. Arxiv 3
Superconducting materials with high critical temperature have the potential to revolutionize many fields, including military, electronic communications, and power energy. Therefore, Scientists around the world have been tirelessly working with the ultimate goal of achieving high temperature superconductivity. In 2023, a preprint by S. Lee et al in South Korea claimed the discovery of ultra-high-temperature superconductivity with a critical temperature of up to 423 K in Cu-doped lead-apatite (LK-99) (arXiv:2307.12008, arXiv:2307.12037), which caused a worldwide sensation and attention. Herein, the electronic structures, phonon dynamics, and electrical conductivities of LK-99 and its parent compound lead-apatite have been calculated using first-principles methods. The results show that the lead-apatite compound and the LK-99 compound are insulator and half-metal respectively. The flat band characteristic is consistent with previous calculations. The electrical conductivity of LK-99 compound shows two extreme point, and the electrical conductivity along the C-axis increases significantly after 400 K. The phonon dispersion spectra of the compounds were investigated, demonstrating their dynamic instability.
4. University of Illinois “Need to synthesize Cu2S-free LK-99 to verify superconductivity” Arxiv 4.
LK-99 must be synthesized without any Cu2S to allow unambiguous validation of the superconducting properties of LK-99.
5. The Indian team is suspected to have leaked a new video “in the video is another sample, but ferromagnetic”
6. Douyin user Newton’s re-engraving results of the flame laser sword (seems to be ferromagnetic)
7. Arxiv 5 – Kunming Institute of Physics and Engineering – “Electronic Structure Computational Paper”
Our calculations cannot determine whether LK99 is a superconductor, but provide some clues and suggestions for its flat band properties.
8. Arxiv 6 – Max Planck Institute – “Density Functional Theory Simulation Computation Paper”
“We computed the maximum projected Wannier function from density functional theory simulations and constructed a minimal two-orbital triangular lattice model containing a copper (3dxz, 3dyz) substrate, and a copper (3dxz, 3dyz) and oxygen ( 2px, 2py) four-orbital twisted honeycomb model of the substrate. Since the Coulomb interaction Ud is much larger than the potential energy difference between copper and oxygen, charge transfer will occur when the hole filling fraction nh > 1. We further calculated the interaction parameter , and the possible insulating states and corresponding spin-exchange couplings are discussed.”
9. Awana VPS Indian team thinks yesterday’s levitating sample is not superconducting but composite magnetic.
10. Quantum Energy Research Institute changed the nature of the company and applied for a trademark
The original Korean researchers have changed their company from a research and development company to a manufacturing company.
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