Single-crystal high entropy perovskite oxide epitaxial films

Examples of single-crystal epitaxial thin films of a high entropy perovskite oxide are synthesized. Pulsed laser deposition is used to grow the configurationally disordered $AB{\mathrm{O}}_{3}$ perovskite $\mathrm{Ba}(\mathrm{Z}{\mathrm{r}}_{0.2}\mathrm{S}{\mathrm{n}}_{0.2}\mathrm{T}{\mathrm{i}}_{0.2}\mathrm{H}{\mathrm{f}}_{0.2}\mathrm{N}{\mathrm{b}}_{0.2}){\mathrm{O}}_{3}$ epitaxially on $\mathrm{SrTi}{\mathrm{O}}_{3}$ and MgO substrates. X-ray diffraction and scanning transmission electron microscopy demonstrate that the films are single phase with excellent crystallinity and atomically abrupt interfaces to the underlying substrates. Atomically resolved electron-energy-loss spectroscopy mapping shows a uniform and random distribution of all $B$-site cations. The ability to stabilize perovskites with this level of configurational disorder offers new possibilities for designing materials from a much broader combinatorial cation pallet while providing a fresh avenue for fundamental studies in strongly correlated quantum materials where local disorder can play a critical role in determining macroscopic properties.