Flat bands promoted by Hund's rule coupling in the candidate double-layer high-temperature superconductor La 3 Ni 2 O 7 under high pressure

This work describes systematic strongly correlated electronic structure calculations for the candidate double-layer high-temperature superconductor La${}_{3}$Ni${}_{2}$O${}_{7}$ under pressure. These reveal the localized-itinerant duality of Ni ${d}_{{z}^{2}}$ electrons, flat ${d}_{{z}^{2}}$ and ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ quasiparticle bands, and strong interlayer antiferromagnetic correlations due to the interplay of orbital-selective Mott, Hund, and Kondo physics. These results imply a two-component theory with possibly preformed interlayer pairing for the high-temperature superconductivity in pressurized La${}_{3}$Ni${}_{2}$O${}_{7}$. The strange metallicity in the normal state is also explained…

• NN
  National Natural Science Foundation of China

  Awards: 11974397, 12174429
• CA
  Chinese Academy of Sciences

  Award: XDB33010100