2023 Spring Graduate Colloquium Series: Balaram Regmi

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 ABO3perovskite Ba(Zr0.2Sn0.2Ti0.2Hf0.2Nb0.2)O3 epitaxially on SrTiO3 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.

Keywords: Epitaxially, B-site cations,spectroscopy