Interfacial Engineering Enabled Novel Bi-Based Layered Oxide Supercells with Modulated Microstructures and Tunable Physical Properties

Abstract

Two-dimensional layered materials hold great significance to fundamental scientific research and future nanoscale device applications. Besides the well-studied graphene and dichalcogenides, oxide-based layered materials are another family attracting significant research interests, for example, the Bi-based Bi 3 Fe 2 Mn 2 O 10-δ layered supercell (called BFMO322 SC) structure. BFMO322 SC is an excellent room-temperature multiferroic material, but its growth mechanism is unclear. In this work, Bi 2 Fe 1–x Mn x O 6 thin films with different Fe/Mn molar ratios were deposited on CeO 2 buffer layers by pulsed laser deposition. By varying the Fe/Mn molar ratios, it has been determined that Mn can favor the growth of Bi-based layered structures, while Fe cannot facilitate the growth. A series of novel layered supercell structures can be obtained by manipulating the growth kinetics at the substrate/film interface, as achieved by precisely controlling the growth conditions. More interestingly, the magnetization and optical band gap of the Bi-based layered structures can be tuned by varying the Fe/Mn molar ratios. This original work has demonstrated the power of interfacial engineering in enabling new Bi-based layered structures and thus is of great significance for the design of new layered structures with multifunctionalities.