Oxygen-intercalated Ruddlesden-Popper nickelate: giant resistive switching and emergent multi-electronic phase...

Rare-earth nickelates exhibit multi-electronic phases that can be dynamically modulated by external stimuli, rendering them promising for neuromorphic computing and sensor applications. However, conventional modulation techniques, such as element doping and ionic liquid gating, typically induce only a single electronic state, thereby weakening the metal-insulator transition and limiting device functionality. Here, we demonstrate that (NdNiO₃)_n:NdO samples can sustain multiple electronic states through the intercalation of oxygen ions into Ruddlesden-Popper structures via oxygen annealing. This approach achieves a remarkable seven-orders-of-magnitude modulation in resistivity at 250 K and induces non-Fermi liquid behavior with a power-law exponent of 2.75, distinct from the 0.25 exponent observed in perovskite NdNiO₃. Theoretical analysis reveals that intercalated oxygen ions mimic the effect of metallic dopants, inducing a ground-state transition from an antiferromagnetic insulator to a ferromagnetic metal. Near the phase transition temperature, the formation of conductive pathways leads to a high-conductivity metallic state. These findings offer crucial insights into oxygen-ion dynamics in Ruddlesden-Popper systems, advancing the design and optimization of strongly correlated oxides for next-generation electronic technologies.