Twisted complex oxide lateral homostructures

Epitaxial growth, thin film deposition by which the crystalline layers with well-defined orientations grown atop single crystal substrates, is indispensable in condensed matter science and semiconductor industry, given that it delivers high quality films comparable to single crystals. Over the past decades, epitaxial growth has enabled efficient interface and strain engineering of functional materials, which has played a key role in renovating modern science and a wide spectrum of technically important applications. In terms of epitaxial growth, the selection of single crystal substrates determines the foundation template for the deposited materials. Namely, the lattice constrains and crystalline orientations of deposited materials are subject to selected template beneath, thus the allowed epitaxial degrees of freedom is determined once a specific substrate is chosen.

In this talk, using multiferroic BiFeO₃ as a model system, we propose an efficient approach to fabricate twisted oxide lateral homostructures with various conjunction tunability, including crystalline orientation, epitaxial constrain and phase stability. With a patterned prototype device, we further demonstrate that the proposed approach is not only compatible with conventional lithography and etching processes, but also versatile for fabricating various twisted complex materials. Additionally, we show that the lateral homostructures can also be assembled by combining structurally-different polymorphs, forming interfaces with unconventional physical properties. Our results evidence the excellent controllability and unbounded conjunction tunability of the lateral homostructures using the proposed method, allowing epitaxial films to be assembled at particular position in the plane, as if they were artificially “weaved”. Such an approach not only provides a new way to design twisted lateral homostructures, but also depicts an different scene of epitaxial growth.