Engineering Interfaces with SrTiO₃ Bicrystal Membranes

Engineering interfaces of materials at the atomic scale enables precise control and modification of their functional properties. Fabricating free-standing membranes is a promising approach to creating novel hetero/homo interfaces, which are not possible in epitaxially grown films. In this work, we demonstrate the synthesis of free-standing SrTiO₃ membranes and twist them at various in-plane angles, resulting in the formation of periodic and aperiodic arrangements. The twist angles are characterized by X-ray diffraction and scanning transmission electron microscopy. By combining scanning electron microscopy, atomic force microscopy, and ellipsometry, we investigate the surface morphology, bond formation and physical properties at the interface of the stacked membranes. Polarization-dependent photoemission electron microscopy coupled with X-ray absorption spectroscopy demonstrates hybridization change, and orbital anisotropy at the interface of bicrystal membranes.