Quantum anomalous Hall effect in a three-dimensional topological-insulator–thin-film-ferromagnetic-metal heterostructure

We theoretically show that the three-dimensional (3D) topological insulator (TI)/thin-film ferromagnetic metal (FMM) heterostructure is possible to be a quantum anomalous Hall (QAH) with wide global band gap. Studying structure and weight distributions of eigenstates, we demonstrate attachment metallic thin film on 3DTI can shift topologically nontrivial state into layers due hybridization bands around original Dirac point. By introducing magnetic exchange interaction in thin-film layers, compute conductivity anisotropy suggest appearance wider gap realizing QAH effect than usual materials, such as magnetically doped films 3DTI/ferromagnetic heterostructures. Our results indicate 3DTI/thin-film FMM may implement even at room temperature, which will pave way experimental realization other exotic phenomena.