Strain landscapes and self-organization of free surfaces in complex oxide epitaxy
Felip Sandiumenge. Journal of Materials Research,Volume 32, Issue 21. Invited Review to Focus Issue: Jan Van Der Merwe and the Computer Age. https://doi.org/10.1557/jmr.2017.317
The growth behavior of epitaxial transition metal oxides with the perovskite structure often shows discrepancies with models established for semiconductor and metal films. The reason is rooted in the versatility of such octahedral framework structures to accommodate the interfacial dissimilarity and the participation of strongly coupled electron and lattice degrees of freedom in strain relaxation mechanisms. Here, we revisit the behavior of the prototypic La0.7Sr0.3MnO3 manganite under specific growth conditions, enabling the isolation of pure octahedral tilting and misfit dislocation mechanisms in the same material. Analysis of the observed behavior provides insights into the competition between octahedral tilting and classical relaxation mechanisms by misfit dislocations or domain formation, and the effect of additional contributions to dissimilarity such as symmetry mismatch and polar discontinuities. Moreover, given the intimate association between misfit relaxation and self-organization mechanisms, opportunities and limitations of the observed behavior in the generation of novel bottom-up functional nanostructures is also addressed.