High-Temperature Diffusion Enabled Epitaxy of the Ti-O System.

High temperatures promote kinetic processes that can drive crystal synthesis toward ideal thermodynamic conditions, thereby realizing samples of superior quality. While accessing very high temperatures in thin-film epitaxy is becoming increasingly accessible through laser-based heating methods, demonstrations of such utility are still emerging. The study realizes a novel self-regulated growth mode in the Ti-O system by relying on thermally activated diffusion of oxygen from an oxide substrate. The controlled diffusion enables oxidation state selectivity of single-phase films with superior crystallinity to conventional approaches as evidenced by structural and electronic measurements. The diffusion-enabled epitaxy is potentially of wide use in the growth of transition metal oxides, opening up new opportunities for ultra-high purity epitaxial platforms based on d-orbital systems.