Growth and transport properties of topological insulator Bi₂Se₃ thin film on a ferromagnetic insulating substrate

Exchange coupling between topological insulator and ferromagnetic insulator through proximity effect is strongly attractive for both fundamental physics and technological applications. Here we report a comprehensive investigation on the growth behaviors of prototype topological insulator Bi₂Se₃ thin film on a single-crystalline LaCoO₃ thin film on SrTiO₃ substrate, which is a strain-induced ferromagnetic insulator. Different from the growth on other substrates, the Bi₂Se₃ films with highest quality on LaCoO₃ favor a relatively low substrate temperature during growth. As a result, an inverse dependence of carrier mobility with the substrate temperature is found. Moreover, the magnetoresistance and coherence length of weak antilocalization also have a similar inverse dependence with the substrate temperature, as revealed by the magnetotransport measurements. Our experiments elucidate the special behaviors in Bi₂Se₃/LaCoO₃ heterostructures, which provide a good platform for exploring related novel quantum phenomena, and are inspiring for device applications.