Nickelate superconductors: Multiorbital nature and spin freezing

Abstract

Superconductivity has recently been reported in Sr-doped NdNiO${}_{2}$ thin films. This work considers the effect of Hund coupling and crystal field splitting in a simple model system and shows that a multiorbital description of nickelate superconductors is warranted, especially in the strongly hole-doped regime. An analysis of this system, inspired by the spin-freezing theory of unconventional superconductivity, furthermore reveals that Nd${}_{0.8}$Sr${}_{0.2}$NiO${}_{2}$ has strongly enhanced local spin fluctuations due to the interplay of two spin-freezing crossovers.

Topics & Concepts