High-Throughput Design of Epitaxial Orientation for Functional Thin Films

The structure and properties of functional thin films are highly sensitive to their epitaxial orientations. However, the orientation of the thin film is typically constrained by that of the substrate, making it challenging to achieve distinct orientations between the thin film and the substrate. The use of buffer layers is an effective approach to manipulate the epitaxial orientations of functional thin films. Nevertheless, this method requires precise screening of buffer layer parameters that may influence the orientation of the overlying functional layer, making the process labor-intensive and time-consuming. Here, a high-throughput strategy is proposed for screening buffer layer parameters. Taking the epitaxial growth of PbZr_1-xTi_xO₃ ferroelectric films as a model system, the optimal thickness of the CoFe₂O₄ buffer layer is successfully determined, enabling the epitaxial growth of [111]-oriented PbZr_0.2Ti_0.8O₃ on a [001]-oriented Mica substrate. Furthermore, a composite buffer layer structure consisting of SrRuO₃ and CoFe₂O₄ is screened, which facilitated the epitaxial growth of [111]-oriented PbZr_1-xTi_xO₃ films on a [001]-oriented SrTiO₃ substrate. This work establishes an efficient approach for the high-throughput screening of buffer layer structures and provides valuable insights into the design of epitaxial functional thin films beyond conventional substrate constraints.