Manipulation of the Topological Hall Effect with Electric Field in Top-Gated (Bi,Sb)₂Te₃ on EuIG

Topological Hall effect (THE), a new member of the “Hall” family, is an electrical transport feature of systems hosting chiral spin textures like skyrmions. Recently, THE has been observed in topological insulator (TI) heterostructures possessing a strong spin-orbit coupling and a broken spatial inversion symmetry when interfaced with a magnetic layer. However, the electrical manipulation of THE has rarely been addressed. In this work, we report a giant THE signal exceeding 3.1 µΩ·cm coexisted with AHE (3.9 µΩ·cm) at 2 K in a 4 nm TI (Bi,Sb)₂Te₃ (BST) heterostructure with a ferrimagnetic insulator europium iron garnet. Dependences of temperature, magnetic field angle, and gate bias were investigated in a four-terminal Hall bar device implemented with a top electrical gate. The THE diminished with increasing temperatures and disappeared above 75 K. Furthermore, the observation of THE at zero fields suggested a stable skyrmion phase without the support of an external magnetic field. The magnitude of THE remained nearly the same up to 70° as the magnetic field gradually tilted away from the surface normal (0°) to the in-plane direction (90°). Most importantly, the sign of THE was switched from negative to positive as carriers in BST were altered from electrons to holes via the gate bias, consistent with the prediction of a skyrmion-driven THE. Our demonstration of electrical manipulation of THE in TI-based heterostructures has important technological implications for ultralow power skyrmion-based spintronics.