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

Abstract

We studied the magneto-optical Kerr effect (MOKE) of two-dimensional (2D) heterostructure CrI3/In2Se3/CrI3 using density functional theory calculations and symmetry analysis. The spontaneous polarization in the In2Se3 ferroelectric layer and the antiferromagnetic ordering in CrI3 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.

Electric Field-Controlled Magneto-Optical Kerr Effect in A-Type Antiferromagnetic Fe2CX2 (X = F, Cl) and Its Janus Monolayer

“…It is particularly useful for detecting, measuring, and manipulating magnetic systems, including two-dimensional (2D) magnets. − Previously, MOKE was thought to be active only in ferromagnetic (FM) or ferrimagnetic (FiM) materials. However, recent theoretical and experimental research has shown that MOKE also exists in antiferromagnetic (AFM) materials with zero magnetization. − Furthermore, altermagnets, which are recently emerged magnetic materials with vanishing net magnetization, have also shown promising potential for magneto-optical activity. , In general, the symmetry broken in magnetic systems, including time reversal ( T ) and space inversion ( I ) symmetry, is essential for magneto-optical effects . In AFM materials with broken T symmetry, MOKE could be activated by breaking I symmetry through spatial asymmetry, external fields, special spin structures, and other means. − ,− …”

Layer Control of Magneto-Optical Effects and Their Quantization in Spin-Valley Splitting Antiferromagnets

“…For a 2D system ( σ yz = 0, σ zx = 0), the MOE is also suppressed by some scriptO symmetries [e.g., scriptO may be M x , M y , C 2 x , and C 2 y ] as well as limited by some combined scriptTS symmetries [e.g., scriptS may be M z , C 2 z , C 3 z , C 4 z , C 6 z )] due to the odd property of σ xy under these symmetries . Hence, by breaking above symmetries, MOE may also emerge in more commonly available collinear AFMs. − From the nanoscience application perspective, it is much desirable to enrich the MOE family in 2D collinear AFMs because of the emergent valley-indexes, − layer physics, ,− and multiferroic order. − Importantly, it is highly desirable to realize the long-sought spin-splitting in 2D AFMs, which has triggered extensive attention recently benefiting from the versatile development of altermagnetism. − …”