Tuning the Curie temperature of a two-dimensional magnet/topological insulator heterostructure to above room temperature by epitaxial growth
Wenyi Zhou, Alexander J.R. Bishop, Xiyue S. Zhang, Katherine Robinson, Igor Lyalin, Ziling Li, Ryan Bailey-Crandell, Thow Min Jerald Cham, Shuyu Cheng, Yunqiu Kelly Luo, Daniel C. Ralph, David A. Muller, Roland Kawakami
Abstract
The heterostructures of 2D magnets and topological insulators are attractive candidates for quantum anomalous hall effect and highly-efficient spin-orbit torque switching. To better study these phenomena, it will be crucial to synthesize epitaxial heterostructures for scalability while maintaining high-quality interfaces to preserve the topological surface states and having the Curie temperature (T${}_{C}$) above room temperature. Here, the authors utilize molecular beam epitaxy to tune the T${}_{C}$ in heterostructures of van der Waals (vdW) magnet Fe${}_{3}$GeTe${}_{2}$ and topological insulator Bi${}_{2}$Te${}_{3}$ to above room temperature by varying growth conditions. Electron microscopy reveals the existence of thicker vdW compounds in the Fe${}_{m}$Ge${}_{n}$Te${}_{2}$ family, as well as some intercalants in between vdW gaps, which are possible origins for the enhanced T${}_{C}$.