Strain-induced metal-insulator transition in t2g electron system of perovskite titanate S m0.5 C a0.5Ti O3 films

We have demonstrated a strain-induced metal-insulator transition for weak Jahn-Teller effects in a t2g electron system of Sm0.5Ca0.5TiO3, which has metallic ground states in the bulk. A clear variation of electronic properties in Sm0.5Ca0.5TiO3 thin films was investigated as a function of epitaxial stain by changing a substrate and the film thickness. Under strong biaxial tensile strain, metallic behaviors were completely eliminated, as evidenced by the temperature dependence of resistivity. The observed metal-insulator transition was consistent with the behavior of the Ti 3d density of states at the Fermi level seen in valence band hard x-ray photoemission spectra.