“…Because scriptI is equivalent to scriptM z scriptC 2 , where scriptM z is the mirror reflection symmetry (mirror perpendicular to the z direction) and scriptC 2 is the in-plane inversion symmetry, the activation of MOKE can be achieved by breaking either scriptM z or scriptC 2 , as confirmed by some theoretical and experimental reports. ,, In general, MOKE is not active in antiferromagnetic systems, where the net magnetization is zero and the scriptT scriptI symmetry is usually preserved. However, several first-principles and experimental studies have predicted or verified a non-negligible MOKE in some antiferromagnets, where the scriptT scriptI symmetry is broken by either the spatial asymmetry or chirality of the crystal or spin structure even though the net magnetization is zero. ,,− In addition to its fundamental interest, the presence of MOKE in an antiferromagnet introduces additional perspectives, because, on the one hand, it challenges the traditional microscopic origin of the Kerr effect, while, on the other hand, it can be exploited in antiferromagnetic spintronics as a result of the insensitivity to external magnetic fields and ultrafast terahertz (THz) spin dynamics. − …”