Formation of Two-dimensional Iron Oxide at the Graphene/SiC(0001) Interface

Various elements are known to intercalate into the two-dimensional (2D) interface between graphene and a SiC substrate. By leveraging this intercalation phenomenon, we here demonstrate the fabrication of a crystalline 2D iron oxide at the graphene/SiC(0001) interface. Atomic-resolution electron microscopy revealed that the 2D iron oxide thus obtained is encapsulated by graphene and forms a sharp interface with the SiC substrate. Structural analysis and Mössbauer spectroscopy suggest that the 2D iron oxide exhibits a wüstite-like structure. This approach provides a new route for synthesizing 2D transition-metal oxides and enables the exploration of novel 2D materials.