Constructing topological insulator-ferromagnet heterojunctions of Bi₂Se₃/Fe₃GeTe₂ and Bi₂Te₃/Fe₃GaTe₂

Heterostructures composed of topological insulators and ferromagnets are predicted to exhibit the quantum anomalous Hall effect (QAHE). The morphology and interfacial structure have a significant impact on physical properties and transport performances of such heterostructures. Here, we report the epitaxial growth of topological insulators Bi₂Se₃ and Bi₂Te₃ thin films on ferromagnetic substrates of Fe₃GeTe₂ and Fe₃GaTe₂, respectively. The morphology and composition of the Bi₂Se₃ and Bi₂Te₃ thin films were characterized using atomic force microscopy, x-ray photoelectron spectroscopy and Raman spectroscopy. After optimizing growth parameters, we successfully generated large-area films with high crystallinity, presenting new types of topological insulator-ferromagnet heterojunctions for the pursuit of QAHE.