On the Electron Pairing Mechanism of Copper-Oxide High Temperature Superconductivity
| Autor: | O'Mahony, S. M., Ren, Wangping, Chen, Weijiong, Chong, Yi Xue, Liu, Xiaolong, Eisaki, H., Uchida, S., Hamidian, M. H., Davis, J. C. Seamus |
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| Rok vydání: | 2021 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1073/pnas.2207449119 |
| Popis: | 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 ${Bi_2Sr_2CaCu_2O_{8+x}}$. Comment: 23 pages, 5 figures |
| Databáze: | arXiv |
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