Orbital-selective spin-triplet superconductivity in infinite-layer LaNiO2

Abstract

The discovery of superconductivity in infinite-layer nickelates has ignited stark interest within the scientific community, particularly regarding its likely unconventional origin. Conflicting magnetotransport measurements report either isotropic or anisotropic suppression of superconductivity in an external magnetic field, with distinct implications for the nature of superconducting order. In order to ensure a most suited model subject to subsequent many-body analysis, we develop a first-principles-guided minimal theory including Ni dx2−y2, La d3z2−r2, and La dxy orbitals. Amended by the consideration of orbital-selective pairing formation, which emphasises the correlation state of the Ni 3dx2−y2 orbital, we calculate the superconducting ordering susceptibility mediated by spin fluctuations. We find a parametric competition between even-parity d-wave and, in contrast to previous studies, odd-parity p-wave pairing, which becomes favorable through a large quasiparticle weight renormalization for Ni 3dx2−y2 electrons. Our findings not only shed light on the distinctiveness of LaNiO2 as compared to cuprate superconductors or nickelates of different rare-earth composition but also suggest similarities to other candidate odd-parity superconductors.

Source-reported materials — not catalogue approval

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