Fabrication of atomically abrupt interfaces of single-phase TiH₂ and Al₂O₃

We report the fabrication of atomically abrupt interfaces of titanium dihydride (δ-TiH₂) films and α-Al₂O₃(001) substrates. With the assistance from reactive hydrogen in plasma, single-phase δ-TiH₂ epitaxial thin films were grown on α-Al₂O₃(001) substrates using the reactive magnetron sputtering technique. Scanning transmission electron microscopy measurements revealed an atomically abrupt interface at the δ-TiH₂(111) film and Al₂O₃(001) substrate. These results indicate that the reactive magnetron sputtering has great potential to deposit various epitaxial thin films of hydrides restricted by the hydrogenation limit. The fabrication of high-quality hydride epitaxial thin films with atomically controlled interfaces paves the way for future hydride electronics.