Direct Observation and Control of Surface Termination in Perovskite Oxide Heterostructures.

Interfacial behavior of quantum materials leads to emergent phenomena such as quantum phase transitions and metastable functional phases. Probes for and real time surface-sensitive characterization are critical for control during epitaxial synthesis of heterostructures. Termination switching in complex oxides has been studied using a variety of probes, often ; however, direct observation of this phenomena during growth is rare.

Electron Doping BaZrO via Topochemical Reduction.

We report the topochemical reduction of epitaxial thin films of the cubic perovskite BaZrO. Reduction with calcium hydride yields n-type conductivity in the films, despite the wide band gap and low electron affinity of the parent material. X-ray diffraction studies show concurrent loss of out-of-plane texture with stronger reducing conditions.

Bandgap Control via Structural and Chemical Tuning of Transition Metal Perovskite Chalcogenides.

Transition metal perovskite chalcogenides are a new class of versatile semiconductors with high absorption coefficient and luminescence efficiency. Polycrystalline materials synthesized by an iodine-catalyzed solid-state reaction show distinctive optical colors and tunable bandgaps across the visible range in photoluminescence, with one of the materials' external efficiency approaching the level of single-crystal InP and CdSe.