Highly asymmetric superconducting dome and strange metallicity in La3Ni2O7

Abstract

The recent discovery of high-temperature superconductivity in La3Ni2O7 under high pressure has stimulated intensive investigations concerning its paring mechanism and a correct description of its effective low-energy physics. Notable experimental observations include the right-triangle-shaped superconducting dome with the maximum Tc of about 80 K and the strange metal behavior in the normal state above Tc. Here we apply the Schwinger boson approach to the bilayer t−V−J model, which allows us to treat well both the magnetic correlations and the superconducting instability. We obtain a global phase diagram with both metallic and superconducting ground states separated by a quantum phase transition, and predict a minimal interlayer superexchange J and a critical (minimal) dz2-hole concentration necessary for the superconductivity, with a highly asymmetric right-triangle-like shape for the Tc curve as well as a maximum Tc comparable with experiments. The normal state is featured with a pseudogap in the spectra of dx2−y2 electrons associated with preformed Cooper pairs and non-Fermi-liquid strange-metal behavior due to hybridization-induced spinon-holon-electron scattering. Our work clarifies the key difference of the two-component scenario of the superconductivity from other mechanisms, and provides a consistent understanding of the high-temperature superconductivity and strange metallic properties of La3Ni2O7 under high pressure.

Source-reported materials — not catalogue approval

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