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On the electron pairing mechanism of copper-oxide high temperature superconductivity
- Source :
- Proceedings of the National Academy of Sciences. 119
- Publication Year :
- 2022
- Publisher :
- Proceedings of the National Academy of Sciences, 2022.
-
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 $t/{\hbar}$ and across the charge-transfer energy gap E, generate 'superexchange' spin-spin interactions of energy $J\approx4t^4/E^3$ in an antiferromagnetic correlated-insulator state. However, Hole doping the 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 ${Bi_2Sr_2CaCu_2O_{8+x}}$. The responses of both E and nP to alterations in the distance {\delta} 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 ${Bi_2Sr_2CaCu_2O_{8+x}}$.<br />Comment: 23 pages, 5 figures
- Subjects :
- Superconductivity (cond-mat.supr-con)
Condensed Matter - Strongly Correlated Electrons
Multidisciplinary
Strongly Correlated Electrons (cond-mat.str-el)
Condensed Matter::Superconductivity
Condensed Matter - Superconductivity
FOS: Physical sciences
Condensed Matter::Strongly Correlated Electrons
Subjects
Details
- ISSN :
- 10916490 and 00278424
- Volume :
- 119
- Database :
- OpenAIRE
- Journal :
- Proceedings of the National Academy of Sciences
- Accession number :
- edsair.doi.dedup.....604193a1916dfb6bc0c288ca83d02043