Atomic‐Scale Control of Electronic Structure and Ferromagnetic Insulating State in Perovskite Oxide Superlattices by Long‐Range Tuning of BO6 Octahedra

Abstract

Abstract Control of BO 6 octahedral rotations at the heterointerfaces of dissimilar ABO 3 perovskites has emerged as a powerful route for engineering novel physical properties. However, its impact length scale is constrained at 2–6 unit cells close to the interface and the octahedral rotations relax quickly into bulk tilt angles away from interface. Here, a long‐range (up to 12 unit cells) suppression of MnO 6 octahedral rotations in La 0.9 Ba 0.1 MnO 3 through the formation of superlattices with SrTiO 3 can be achieved. The suppressed MnO 6 octahedral rotations strongly modify the magnetic and electronic properties of La 0.9 Ba 0.1 MnO 3 and hence create a new ferromagnetic insulating state with enhanced Curie temperature of 235 K. The emergent properties in La 0.9 Ba 0.1 MnO 3 arise from a preferential occupation of the out‐of‐plane Mn d 3 z 2 − r 2 orbital and a reduced Mn e g bandwidth, induced by the suppressed octahedral rotations. The realization of long‐range tuning of BO 6 octahedra via superlattices can be applicable to other strongly correlated perovskites for exploring new emergent quantum phenomena.