Current-Induced Spin and Orbital Polarization in Magnetic Sliding Ferroelectrics

One of the main challenges for modern information read and write technology is how to effectively and precisely modulate the interconversion between electricity and magnetism with a high data density. Herein, it is proposed that two-dimensional magnetic sliding ferroelectrics can serve as a prototypical material platform with tunable electric current-induced magnetization variation, a typical nonequilibrium magnetoelectric coupling process. Using a CrI₃ bilayer as the exemplary material, first-principles calculations are performed to enumerate the monopole values, toroidal vectors, and quadrupole moment tensors. Their switching is also elucidated under a short distance sliding between the two layers, which can effectively flip the electric dipole moment. In addition to spin polarization which is usually studied for magnetic systems, the orbital moment contribution to the magnetoelectric coupling is also evaluated. They are found to be comparable in their magnitude and neither should be omitted, as opposed to equilibrium states. The work helps to reveal the underlining mechanisms among electronics, spintronics, and orbitronics in low-dimensional multiferroic materials.