2022/11/01 by Navinder J. Singh, Singh, Navinder
Physics and Astronomy · #Advanced Chemical Physics Studies #FOS: Physical sciences #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Statistical Mechanics (cond-mat.stat-mech) #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.2211.00400
openalex publication_date 2022/11/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The recent experimental verification of the charge-transfer superexchange mechanism as the microscopic pairing mechanism of high-Tc cuprate superconductivity by Seamus Davis and collaborators\citesea is a tour de force! The correct model for cuprates is the three band Emery model in which oxygen p-orbitals are explicitly taken into account. The doped holes go into these oxygen p-orbitals where they undergo charge-transfer superexchange with unpaired electrons in copper d orbitals. This charge transfer superexchange is the key which leads to bound pairs and superconductivity. In the experimental verification\citesea, the system chosen is Bi2Sr2CaCu2O8+x. What is achieved is the direct functional dependence of the local electron pair density (nP(r)) on local charge transfer energy (\eppd(r)) using state of the art single-electron and electron-pair (Josephson) scanning tunneling microscopy. The quantitative functional dependence of nP(r) on \eppd(r) matches with that indicated and deduced by theory\citet1,t2,t3,t4,t5,t6,t7,t8,t9,t10. The verdict of the experiment settles the debates on the microscopic mechanisms of the cuprate superconductivity in the clear favor of charge-transfer superexchange mechanism. We discuss this development in brief, and present a simple minded approach to the essence of cuprate superconductivity. We discuss what is settled now, and what is not settled yet. A "theoretical minimum" of the high-Tc problem is also discussed.