A Possible Family of Ni-based High Temperature Superconductors

TL;DR

This paper proposes a new family of Ni-based compounds with layered structures as potential high-temperature superconductors, emphasizing their unique electronic and magnetic properties and possible pairing symmetries.

Contribution

It introduces a novel class of Ni-based layered compounds with specific structural and electronic features that could host high-temperature superconductivity upon doping or pressure.

Findings

Prediction of antiferromagnetic parent states

Identification of two independent e_g orbitals near Fermi level

Possible competition between s-wave and d-wave pairing

Abstract

We suggest that a family of Ni-based compounds, which contain [Ni$_2$M$_2$O]$^{2-}$(M=chalcogen) layers with an antiperovskite structure constructed by mixed-anion Ni complexes, NiM$_4$O$_2$, can be potential high temperature superconductors upon doping or applying pressure. The layer structures have been formed in many other transitional metal compounds such as La$_2$B$_2$Se$_2$O$_3$(B=Mn, Fe,Co). For the Ni-based compounds, we predict that the parental compounds host collinear antiferromagnetic states similar to those in the iron-based high temperature superconductors. The electronic physics near Fermi energy is controlled by two e$_{g}$ d-orbitals with completely independent in-plane kinematics. We predict that the superconductivity in this family is characterized by strong competition between extended s-wave and d-wave pairing symmetries.