Abstract
Designing and understanding functional electronic and magnetic properties in perovskite oxides requires controlling and tuning the underlying crystal lattice. Here we report the structure, including oxygen and cation positions, of a single-crystal, entropy stabilized perovskite oxide film of grown on (001). The parent materials range from orthorhombic (, and ) to rhombohedral ( and ), and first principles calculations indicate that these structural motifs are nearly degenerate in energy and should be highly distorted site to site. Despite this extraordinary local configurational disorder on the -site sublattice, we find a structure with unexpected macroscopic crystalline homogeneity with a clear orthorhombic unit cell, whose orientation is demonstrated to be controlled by the strain and crystal structure of the substrate for films grown on and (110). Furthermore, quantification of the atom positions within the unit cell reveals that the orthorhombic distortions are small, close to , which may be driven by a combination of disorder averaging and the average ionic radii. This is a step toward understanding the rules for designing crystal motifs and tuning functional properties through controlled configurational complexity.
- Received 12 March 2020
- Revised 2 April 2020
- Accepted 6 April 2020
DOI:https://doi.org/10.1103/PhysRevMaterials.4.054407
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