Competing Interfacial Reconstruction Mechanisms in La0.7Sr0.3MnO3/SrTiO3 Heterostructures

Interface coupling between complex oxides offers unique possibilities to tailor materials properties and stabilize novel ground states. Understanding the structural reconstruction of the corner-shared octahedral framework and the charge redistribution are crucial for controlling interfacial properties in oxide electronics. Here, we study the interfacial oxygen octahedral behavior in La0.7Sr0.3MnO3/SrTiO3 heterostructure, by directly imaging the oxygen octahedra at the atomic scale and extracting the structural parameters. We combine these experimental results with electronic structure calculations to elucidate the effect of reconstructed MnO6 octahedral geometry on increased interfacial magnetization and conductivity. The Mn valence profiles near the interface are quantitatively analyzed and compared at variant temperatures, revealing the insulating nature of interfacial manganite with reduced Mn valence. This study suggests a pathway to manipulate the interfacial properties and creation of new ground states in complex oxide heterostructures by tuning competing structural and electronic parameters.