Superconductivity in nickel based 112 systems

TL;DR

Recent discovery of superconductivity in nickel-based 112 systems offers a new platform to explore unconventional pairing mechanisms, with ongoing research into their electronic structures, magnetic properties, and pairing symmetries.

Contribution

This paper provides a comprehensive overview of experimental and theoretical progress on nickel-based 112 superconductors, highlighting their electronic and magnetic characteristics.

Findings

Superconductivity observed in nickel-based 112 thin films.

Electronic structures and magnetic excitations characterized.

Open discussions on possible pairing symmetries.

Abstract

Superconductivity has been discovered recently in nickel based 112 infinite thin films $R_{1-x}$A$_x$NiO$_2$ ($R$ = La, Nd, Pr and A = Sr, Ca). They are isostructural to the infinite-layer cuprate (Ca,Sr)CuO$_2$ and are supposed to have a formal Ni 3$d^9$ valence, thus providing a new platform to study the unconventional pairing mechanism of high-temperature superconductors. This important discovery immediately triggers a huge amount of innovative scientific curiosity in the field. In this paper, we try to give an overview of the recent research progress on the newly found superconducting nickelate systems, both from experimental and theoretical aspects. We will focus mainly on the electronic structures, magnetic excitations, phase diagrams, superconducting gaps and finally make some open discussions for possible pairing symmetries in Ni based 112 systems.