Gate-Tunable Anomalous Hall Effect From the Interaction of the van der Waals Antiferromagnet CrI₃ with a Topological-Insulator Surface State

The coupling between topological insulators and magnetic materials can induce exotic topological states which may have useful applications for the development of novel spintronic devices. In this study, we demonstrate the coupling between the 3D topological insulator BiSbTeSe₂ and the 2D layered antiferromagnet CrI₃. Specifically, we assembled a CrI₃/BiSbTeSe₂ heterostructure encapsulated in hexagonal boron nitride (hBN) via stacking of exfoliated few-layer flakes, and observed a large anomalous Hall effect at 4.5 K. We tune the Fermi level of the surface state via electrostatic gating and thereby control the strength of the anomalous Hall signal. We will compare and contrast the results from using antiferromagnetic CrI₃ versus ferromagnetic Cr₂Ge₂Te₆.