UC Berkeley

Recent advances in high-throughput computational workflows are expanding the realm of materials for a range of applications. Here, we report the experimental evaluation of two such predicted candidate ferroelectric perovskite oxides: BiAlO3 and BiInO3. Attempts were made to synthesize polar BiAlO3 and BiInO3 using pulsed-laser deposition. Despite exploring a wide range of temperatures, pressures, substrates, laser fluences, and so on, attempts to grow BiAlO3 with this approach resulted in no perovskite phase and decomposition to Bi2O3 and Bi24Al2O40. Various orientations of BiInO3 films were synthesized on multiple substrates, with the best crystallinity demonstrated for (200)-oriented films on MgO (001). Density-functional theory predicts two energetically competitive ground-state structures for BiInO3: Pnma (nonpolar) and Pna21 (polar). BiInO3 films were studied by using X-ray diffraction and second-harmonic generation (SHG) and found to exhibit the nonpolar Pnma structure. Temperature-dependent SHG and dielectric measurements revealed no transition to the polar structure. Optical transmission-absorption studies suggest a direct bandgap of ∼4.5 eV for BiInO3. Our study underscores the need for additional descriptors for synthesizability in assessing the potential of ferroelectric candidate materials identified from high-throughput materials databases.