Nickelate superconductors——important inspiration for unconventional high-temperature superconductivity

In recent years, superconductivity in nickelates has attracted much attention because the infinite layer nickelates RNiO₂ (R represents rare-earth element) have the same crystal structure and 3d⁹ outer-shell electronic orbital as CaCuO₂, a parent phase of high-temperature cuprate superconductors. Therefore, further study and analysis of nickelates can help us understand the physical origin of unconventional high-temperature superconductivity. This paper will review the current development of nickelate superconductors, mainly covering the discovery of superconductivity in nickelate thin films, the crystal and electronic structure of the 112 phase, the optimization of thin film growth conditions, recent research progress and phase diagram. Finally, a brief summary and future perspectives are presented.