Domain structure of epitaxial SrRuO3 thin films on miscut (001) SrTiO3 substrates

The microstructure of epitaxial ${\mathrm{SrRuO}}_{\mathrm{3}}$ thin films grown on vicinal (001) ${\mathrm{SrTiO}}_{\mathrm{3}}$ substrates with miscut angle of 1.9° and miscut direction of 12° away from [100] direction was studied using transmission electron microscopy (TEM). Cross-section as well as plan-view TEM studies revealed that these films are single domain with the in-plane epitaxial orientation relationship of ${\mathrm{SrRuO}}_{\mathrm{3}}{\mathrm{[001]//SrTiO}}_{\mathrm{3}}\mathrm{[010]}$ and ${\mathrm{SrRuO}}_{\mathrm{3}}{\mathrm{[1̄10]//SrTiO}}_{\mathrm{3}}\mathrm{[100]}.$ This result is in contrast to the previous studies of the ${\mathrm{SrRuO}}_{\mathrm{3}}$ thin films grown on exactly (001) ${\mathrm{SrTiO}}_{\mathrm{3}},$ which are composed of two types of [110] domains with nearly the same volume fraction. The occurrence of these different domain structures is attributed to the step-flow growth of the film on the substrate surface due to the miscut.