Damage-free and atomically precise surface preparation of SrTiO₃

Atomically flat and clean (i.e., defect- and contaminant-free) oxide surfaces are essential to fabricating new interfaces with emerging properties and analyzing the surface electronic structure. We investigated how to apply Ar-sputtering techniques to surface preparation. Defect-related peaks were not observed in the spectra collected from the SrTiO₃(001) surface prepared via time and energy controlled Ar-ion and Ar-gas cluster ion beam sputtering. In addition, surface with a step-and-terrace structure had sub-Angstrom root-mean-square roughness indicating structurally and morphologically fine surface. This work demonstrates that sputtering techniques can be used as pre-cleaning and in-situ preparation processes for fabrication of atomically precise oxide surface and interfaces.