Abstract
Perovskite oxides can host various anion-vacancy orders, which greatly change their properties, but the order pattern is still difficult to manipulate. Separately, lattice strain between thin film oxides and a substrate induces improved functions and novel states of matter, while little attention has been paid to changes in chemical composition. Here we combine these two aspects to achieve strain-induced creation and switching of anion-vacancy patterns in perovskite films. Epitaxial SrVO3 films are topochemically converted to anion-deficient oxynitrides by ammonia treatment, where the direction or periodicity of defect planes is altered depending on the substrate employed, unlike the known change in crystal orientation. First-principles calculations verified its biaxial strain effect. Like oxide heterostructures, the oxynitride has a superlattice of insulating and metallic blocks. Given the abundance of perovskite families, this study provides new opportunities to design superlattices by chemically modifying simple perovskite oxides with tunable anion-vacancy patterns through epitaxial lattice strain.
Highlights
Perovskite oxides can host various anion-vacancy orders, which greatly change their properties, but the order pattern is still difficult to manipulate
The introduction of anion vacancies brings about a diversity of chemical and physical properties; the most widely being studied in perovskite oxides[1,2,3]
Compounds having such anion-defect chains or planes can be synthesized through a variety of approaches such as cationic substitution[7], topochemical and electrochemical reactions[8,9], and under appropriate conditions
Summary
Perovskite oxides can host various anion-vacancy orders, which greatly change their properties, but the order pattern is still difficult to manipulate. This observation suggests that lattice strain can be used to induce and manipulate the anion-vacancy planes and provide a controllable parameter for the development of exotic structural and electronic states in perovskite films.
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