Sliding ferromagnetism in bilayer MnSiSe3 and its application to spintronics

Based on first-principles calculations, we report that the easy magnetization axis in two-dimensional (2D) van der Waals (vdW) magnets can be controlled by the sliding direction, a phenomenon we termed sliding ferromagnetism, directly linked to the second-order perturbation effects of spin-orbit coupling. Furthermore, we construct a ${\mathrm{MnSiSe}}_{3}$/graphene-bilayer-BN-graphene/${\mathrm{MnSiSe}}_{3}$ vdW multiferroic tunnel junction (MFTJ) where the direction of sliding, rather than electric or magnetic fields, drives the device. Here, the sliding ferroelectric bilayer $h$-BN acts as the insulating area, and the sliding ferromagnetic mirrored-bilayer ${\mathrm{MnSiSe}}_{3}$ serves as the electrodes. Our nonequilibrium Green's function calculations demonstrate the existence of multilevel resistance states in this MFTJ. These findings present an approach to manipulating the spin orientation in two-dimensional magnets without magnetic fields, and thus a colorful platform for designing tunable spintronic devices.