Spin tunnel field-effect transistors based on two-dimensional van der Waals heterostructures

A transistor based on spin rather than charge—a spin transistor—could potentially offer non-volatile data storage and improved performance compared with traditional transistors. Many approaches have been explored to realize spin transistors, but their development remains a considerable challenge. The recent discovery of two-dimensional magnetic insulators such as chromium triiodide (CrI3), which offer electrically switchable magnetic order and an effective spin filtering effect, can provide new operating principles for spin transistors. Here, we report spin tunnel field-effect transistors (TFETs) based on dual-gated graphene/CrI3/graphene tunnel junctions. The devices exhibit an ambipolar behaviour and tunnel conductance that is dependent on the magnetic order in the CrI3 tunnel barrier. The gate voltage switches the tunnel barrier between interlayer antiferromagnetic and ferromagnetic states under a constant magnetic bias near the spin-flip transition, thus effectively and reversibly altering the device between a low and a high conductance state, with large hysteresis. By electrically controlling the magnetization configurations instead of the spin current, our spin TFETs achieve a high–low conductance ratio approaching 400%, suggesting they could be of value in the development of non-volatile memory applications. A tunnel field-effect transistor with spin-dependent outputs that are voltage controllable and reversible can be created using a dual-gated graphene/CrI3/graphene tunnel junction.