Multiple relaxation mechanisms in $SrTiO3/SrRuO3$ heterostructures

We have studied stress relaxation mechanisms in epitaxial $(001)$ $SrTiO3$ films grown on $(001)$ $LaAlO3$ substrates with $SrRuO3$ buffer layers. A theoretical analysis has been undertaken to understand the variation of the lattice parameters of $SrTiO3$ epitaxial films, taking into account stress relaxation due to the formation of an orthorhombic polydomain structure in the $SrRuO3$ buffer layer as well as the formation of misfit dislocations at the $LaAlO3/SrRuO3$ and the $SrTiO3/SrRuO3$ interfaces. There exists a critical $SrRuO3$ buffer layer thickness, above which the $SrRuO3$ buffer layer can “screen” the effect of the $LaAlO3$ substrate. It is shown that the internal stress level in films can be controlled using buffer layers that exhibit a structural phase transformation.