Early self-assembled stages in epitaxial SrRuO3 on LaAlO3

The stress-induced self-assembled growth of SrRuO3 on LaAlO3 was studied by atomic force microscopy and x-ray diffraction. SrRuO3 epitaxially grown on LaAlO3 by pulsed laser deposition shows two types of out-of-plane arrangements and four in-plane matches. The lattice mismatch (stress) produced by these arrangements was estimated and correlated with the SrRuO3 growth dynamics. After 1 nm, the SrRuO3 film surface exhibits a ripple structure, which serves as a template for the development of a nanopattern of flat islands. These islands coalesce anisotropically resulting in a regular array of “infinite” wires. The wire coalescence for the 12–20 nm thick film nullifies the surface symmetry, while SrRuO3 keeps growing in three dimensions.