Growth modes, strain states, and electrical transport properties of epitaxial La0.5Sr0.5CoO3 thin films grown on buffered Si substrates

By introducing different buffer layer, textured or epitaxial La0.5Sr0.5CoO3 (LSCO) thin film can be prepared on Si substrate using pulsed laser deposition (PLD) method. Effects of different buffer layers on growth modes, strain states, and electrical transport properties of LSCO thin films were comparatively investigated. Due to small lattice constant mismatch (1.5%) and similarity of crystalline structure between LSCO and SrTiO3 (STO), the LSCO film on the STO buffer layer is epitaxially grown with layer-by-layer (2D) mode, and the film is under tensile strain. However, owing to large lattice constant mismatch (9%), the LSCO film on the MgO buffer layer is c-axis textured with Stranski–Krastanow (S–K) growth mode, and tensile strain can be relaxed almost fully. Correspondingly, these LSCO films exhibit different electrical transport characteristics, such as electrical resistivity, TMITMI, etc., which can be ascribed to difference in growth modes and strain states of the LSCO films.