Growth modes and self-organization in the epitaxy of ferromagnetic SrRuO3 on SrTiO3(001)

We report on the self-organized formation of one-dimensional finger-like structures and the subsequent surface smoothing that occurs in the epitaxial growth of ferromagnetic and conductive SrRuO₃ films on SrTiO₃(001) substrates. We show that at an early stage of growth there are three-dimensional (3D) islands nucleated along the substrate steps, and we detail their coalescence to form fingers and later the coalescence of fingers to form planar surfaces. The influence of the Erlich–Schwoebel barrier on the morphology evolution is demonstrated. We discuss on the driving forces promoting 3D growth at the early stages.