Saturday, September 24, 2022

High-Temperature Superconductivity Understood at Last

Very recommendable! When will we finally discover superconductors at room temperature (a holy grail)? Why are we not spending more money on this critical research?

Perhaps, AI and machine learning could be applied to find other combinations of metals or elements with superconductivity properties. What are we waiting for?

E.g. the Global Warming Hoax and Climate Change Religion would be history instantly! No more eyesore mega size windmill farms and solar power farms spoiling nature and tons of taxpayer money wasted on subsidies for these so called renewable energy!

From the abstract:
"The elementary CuO2 plane sustaining cuprate high-temperature superconductivity occurs typically at the base of a periodic array of edge-sharing CuO5 pyramids. Virtual transitions of electrons between adjacent planar Cu and O atoms, occurring at a rate t/ℏ and across the charge-transfer energy gap E, generate “superexchange” spin–spin interactions of energy J≈4t4/E3 in an antiferromagnetic correlated-insulator state. However, hole doping this CuO2 plane converts this into a very-high-temperature superconducting state whose electron pairing is exceptional. A leading proposal for the mechanism of this intense electron pairing is that, while hole doping destroys magnetic order, it preserves pair-forming superexchange interactions governed by the charge-transfer energy scale E. To explore this hypothesis directly at atomic scale, we combine single-electron and electron-pair (Josephson) scanning tunneling microscopy to visualize the interplay of E and the electron-pair density nP in Bi2Sr2CaCu2O8+x. The responses of both E and nP to alterations in the distance δ between planar Cu and apical O atoms are then determined. These data reveal the empirical crux of strongly correlated superconductivity in CuO2, the response of the electron-pair condensate to varying the charge-transfer energy. Concurrence of predictions from strong-correlation theory for hole-doped charge-transfer insulators with these observations indicates that charge-transfer superexchange is the electron-pairing mechanism of superconductive Bi2Sr2CaCu2O8+x."  

High-Temperature Superconductivity Understood at Last | Quanta Magazine A new atomic-scale experiment all but settles the origin of the strong form of superconductivity seen in cuprate crystals, confirming a 35-year-old theory.

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