Characterizing the superconducting instability in a two-orbital $d$-$s$ model: insights to infinite-layer nickelate superconductors

Abstract

Motivated by the recent realization of the infinite-layer nickelate superconductivity (SC), we quantitatively investigate a two-orbital $d$-$s$ model by dynamic cluster quantum Monte Carlo calculations. Focusing on the impact of inter-orbital hybridization on the superconducting properties, our simulations indicate that the $d$-$s$ hybridization strength has a decisive role in the suppression of the $d$-wave pairing in the doping regime relevant to infinite-layer nickelates. Although we confirm on the single-orbital description at weak hybridization, at relatively large hybridization, there exists a constructive effect of the non-negligibly finite $s$ orbital occupancy on inhibiting the suppression of the superconductivity. More strikingly, there exists a possible SC enhancement at large enough Hubbard interaction via large $d$-$s$ hybridization. We further provide some insights on the relevance of $d$-$s$ model to infinite-layer nickelates.

7 pages, 3 figures