Atomically flat SrO-terminated $SrTiO3(001)$ substrate

We show that atomically flat single SrO-terminated $SrTiO3(001)$ substrates can be obtained through simple high-temperature treatment. Amplitude-modulation atomic force microscopy with phase-lag analysis and x-ray photoelectron spectroscopy, have been used to demonstrate that the ratio between the two chemical terminations can be tailored by choosing the annealing time. Moreover, the progressive SrO surface enrichment (up to 100%) is accompanied by a self-assembly process which results in the spatial separation at the nanoscale of both chemical terminations. We further demonstrate that this opens a interesting avenue for selective chemical reaction and growth of oxide nanostructures.