Interfacial charge transfer mediated tunable electronic phase transition at complex oxide heterostructures

Interfacial charge transfer in functional oxide heterostructures presents fascinating fundamental physical phenomena as well as holds limitless potential for new generation device applications. Specifically, bilayer thin films composed of strongly correlated 3d Nickelate and 5d Iridate materials, characterized by robust spin-orbit coupling (SOC), unveil intriguing interfacial behaviors. These phenomena give rise to an entirely novel type of electronic phase transition, contingent upon the correlations/SOC strength of the constituent layers. Within these bilayers, the 3d Nickelate layer serves as compelling testing grounds, with their behavior intricately tied to oxygen stoichiometry. Furthermore, the dimensionality of these thin film heterostructures emerges as a pivotal regulator, enabling precise tuning of this unique phase transition originating from the interfacial interactions. Our comprehensive investigation, facilitated by X-ray absorption spectroscopy, sheds light on the unconventional charge-transfer dynamics unfolding at the 5d-3d interface.