Influence of symmetry mismatch on heteroepitaxial growth of perovskite thin films

Epitaxial thin films of (110) orthorhombic CaRuO3 grown on orthorhombic (110) NdGaO3 and cubic (001) (LaAlO3)0.3–(Sr2AlTaO6)0.7 (LSAT) substrates serve as a model system isolating the influence of oxygen octahedron distortion on epitaxial growth of thin films. CaRuO3 grows as a coherent single crystal on NdGaO3 with an atomically smooth surface, whereas CaRuO3 on LSAT is multidomain with a rough surface despite the equivalent film stoichoimetry and average lattice mismatch between CaRuO3 and the substrates. Anisotropic metallic resistivity of the single crystal CaRuO3 was observed at 10 K with different electrical behaviors as a function of temperature for [1¯10] and [001] in-plane directions.