Epitaxial growth of thin-film heterostructures is generally considered the most successful procedure to obtain interfaces of excellent structural and electronic quality between three-dimensional materials. However, these interfaces can only join material systems with crystal lattices of matching symmetries and lattice constants. We present a novel category of interfaces, the fabrication of which is membrane-based and does not require epitaxial growth. These interfaces therefore overcome limitations imposed by epitaxy. Leveraging the additional degrees of freedom gained, we demonstrate atomically clean interfaces between three-fold symmetric sapphire and four-fold symmetric SrTiO3. Atomic-resolution imaging reveals structurally well-defined interfaces with a novel moir\'e-type reconstruction.
@article{arxiv.2403.08736,
title = {Interface Design Beyond Epitaxy: Oxide Heterostructures Comprising Symmetry-forbidden Interfaces},
author = {Hongguang Wang and Varun Harbola and Yu-Jung Wu and Peter A. van Aken and Jochen Mannhart},
journal= {arXiv preprint arXiv:2403.08736},
year = {2024}
}