Effect of Polar (111)-Oriented SrTiO3 on Initial Perovskite Growth

• Published in: Crystal growth & design Vol. 16; no. 4; pp. 2357 - 2362
• Main Authors: Hallsteinsen, Ingrid, Nord, Magnus, Bolstad, Torstein, Vullum, Per-Erik, Boschker, Jos E, Longo, Paulo, Takahashi, Ryota, Holmestad, Randi, Lippmaa, Mikk, Tybell, Thomas
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06.04.2016
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.6b00143

In crystalline thin film growth a prerequisite is substrate surfaces with a stable and uniform structure and chemical composition. Various substrate treatments were used to obtain atomically smooth, step-and-terrace (111)-oriented SrTiO3 with uniform cation layers at the surface, i.e., single termination. The surface control enables subsequent layer-by-layer epitaxial growth of perovskite thin films of La0.7Sr0.3MnO3, LaFeO3, and BaTiO3. Reflection high-energy electron diffraction and electron energy loss spectroscopy revealed that a single chemically intermixed (A,A′)­BO3 perovskite layer formed at the interface. As the terminating layer of (111) SrTiO3 is polar, a surface reconstruction consisting of TiO x surface layers is expected, and the intermixing at the interface can be understood as A′-cations from the film material compensating an A-cation deficient substrate surface during initial growth. This finding has important consequences for engineered interfaces between perovskite thin films and polar substrate facets.