Flat bands promoted by Hund's rule coupling in the candidate double-layer high-temperature superconductor <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>La</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi>Ni</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:mrow></mml:math> under high pressure
Yingying Cao, Yi‐feng Yang
Abstract
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 from the quasiparticle lifetimes.