Artificial Twisting of Freestanding Perovskite Heterostructures

The integration of dissimilar materials in heterostructures has been pivotal in advancing modern materials science and technology. The advent of 2D van der Waals materials has expanded such concept to the mechanical assembly of layered materials such as graphene and transition metal dichalcogenide. Recently, applying the methodology of 2D heterostructures to ultra-thin complex oxides has opened new avenues to explore a rich spectrum of novel functionalities such as superconductivity, magnetism, and ferroelectricity. To deal with the strong 3D bonding oxides, ultra-thin perovskite membranes, including titanates, have been investigated to understand how to create wafer-scale membranes using a water-soluble sacrificial epitaxial layer, Sr₃Al₂O₆ (SAO) and other related materials with different lattice constants. In this talk, we discuss the artificial twisting of perovskite membranes. High-quality perovskite membranes were fabricated by creating perovskite/SAO/substrate heterostructures using pulsed laser deposition. The perovskite membranes were then released by dissolving the heterostructure in the water and subsequently transferred. Moreover, we carried out a systematic characterization of twisted perovskite membranes and will report the details of reconstructed superstructures at the interface in twisted perovskite membranes.