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X-WR-CALNAME:Laboratoire de physique des Solides
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BEGIN:VEVENT
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DTSTART;TZID=Europe/Paris:20211109T110000
DTEND;TZID=Europe/Paris:20211109T180000
DTSTAMP:20211103T095700
UID:MEC-56584778d5a8ab88d6393cc4cd11e090@lps.u-psud.fr
CREATED:20211103
LAST-MODIFIED:20211103
PRIORITY:5
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SUMMARY:J.C. Séamus Davis, On the Electron Pairing Mechanism of Copper-Oxide High Temperature Superconductivity
DESCRIPTION:\nJ.C. Séamus Davis. University of Oxford – University College Cork – Cornell University\n\n\n\n  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/ℏand across the charge-transfer energy gap ε,  generate ‘superexchange’ spin-spin interactions of energy J≈4t^4/E^3 in an antiferromagnetic correlated-insulator state. However, hole doping this CuO2 plane converts this into a 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 controlled by the charge-transfer energy scale ε. To explore this hypothesis directly at atomic-scale, we combine single-particle and electron-pair (Josephson) scanning tunneling microscopy to visualize both ε and the electron-pair density ns, in Bi2Sr2CaCu2O8+x.  This technique determines the responses of both ε and ns to alterations in the distance δ between planar Cu and apical O atoms, thereby revealing the impact of varying ε on ns for a cuprate superconductor. Conformation of the predictions from strong-coupling theory for hole-doped charge-transfer insulators with these observations, indicates that charge-transfer superexchange is the electron-pairing mechanism of Bi2Sr2CaCu2O8+x.\n\n\n\nLe séminaire  SMQ exceptionnel sera en mode hybride. \n\n\n\nParticiper à la réunion Zoom https://zoom.us/j/94643588952?pwd=YnZZdmhxRXZ4ZE1pSGxVamFmWitPUT09\n\n\n\nID de réunion : 946 4358 8952Code secret : 2b1stj\n
URL:https://www.lps.u-psud.fr/en/events/c-seamus-davis-on-the-electron-pairing-mechanism-of-copper-oxide-high-temperature-superconductivityj-2/
CATEGORIES:exceptional seminar,Seminar SMQ,Seminars
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