Research progress and prospect of ambient-pressure nickelate superconducting thin films

This review summarizes recent advances in the study of nickelate superconducting thin films under ambient pressure, with a focus on material synthesis, property modulation, and mechanistic investigation of infinite-layer and bilayer Ruddlesden-Popper (RP) phase nickelates. We systematically analyze the characteristics and applicability of key fabrication techniques, including pulsed laser deposition (PLD), oxide molecular beam epitaxy (OMBE), and gigantic-oxidative atomic-layer-by-layer epitaxy (GOALL-Epitaxy). Research demonstrates that through multi-element doping and strain engineering, the superconducting transition temperature (T_c) of infinite-layer nickelates has been enhanced to nearly 40 K. Moreover, bilayer RP nickelate thin films have achieved superconducting transitions with onset temperatures exceeding 40 K at ambient pressure, exhibiting zero resistance, complete diamagnetism, and unconventional superconducting phase diagrams. Finally, we provide a concise summary and outlook regarding the further development of nickelate thin film fabrication technologies, the discovery of novel material systems, and the elucidation of their microscopic pairing mechanisms.