Electrical Control of Magnetism in Atomically Thin Magnets

Controlling magnetism by purely electrical means is a key challenge to fast and energy efficient spintronics devices. Electrical control of magnetism has been explored in a variety of materials including dilute magnetic semiconductors, ferromagnetic metal thin films, magneto-electrics and multiferroics, but remains a formidable challenge. The recent discovery of two-dimensional van der Waals magnets [1-2] has opened a new door for electrical control of magnetism at the nanometer scale through the van der Waals heterostructure device platform. In this talk, I will discuss our recent observations on electrical control of magnetism in 2D magnet CrI3, and how to utilize it to build a new prototype of spin transistor. In particular, in bilayer CrI3, we observed large linear magnetoelectric effect, whose sign and magnitude are solely determined by its spin symmetry [3]. We also demonstrated doping can drastically change the interlayer spin order, causing AFM-FM phase transition [4]. This electrical-tunable magnetic phase transition enables robust and reversible switching of magnetization in bilayer CrI3 by small gate voltages. With the above findings, we have built a new prototype of spin transistor: a spin tunneling field-effect transistors (Spin-TFET) based on dual-gated graphene/CrI3/graphene heterostructure [5].References:[1] Huang, B. et al. Nature 546, 270 (2017).[2] Gong, C. et al. Nature 546, 265 (2017).[3] Jiang, S., Shan, J. & Mak, K.F. Nature Materials 17, 406 (2018).[4] Jiang, S., Li, L., Wang, Z., Mak, K.F. & Shan, J. Nature Nanotechnology 13, 549 (2018).[5] Jiang, S., Li, L., Wang, Z., Mak, K.F. & Shan, J. arxiv: 1807.04898