Magneto-optical Kerr Effect in Ferroelectric Antiferromagnetic Two-Dimensional Heterostructures.

We studied the magneto-optical Kerr effect (MOKE) of two-dimensional (2D) heterostructure CrI/InSe/CrI using density functional theory calculations and symmetry analysis. The spontaneous polarization in the InSe ferroelectric layer and the antiferromagnetic ordering in CrI layers break the mirror and the time-reversal symmetry, thus activating MOKE. We show that the Kerr angle can be reversed by either the polarization or the antiferromagnetic order parameter. Our results suggest that ferroelectric and antiferromagnetic 2D heterostructures could be exploited for ultracompact information storage devices, where the information is encoded by the two ferroelectric or the two time-reversed antiferromagnetic states and the read-out is performed optically by MOKE.