Magneto-Optical Kerr Effect as an Evidence of the Interplay Between Non-Equilibrium Orbital Magnetism and the Second Order Hall Effect

Magneto-optics has been widely used to identify magnetic properties in different materials and the spin accumulation in semiconductors and heavy metals. Here, the corresponding Kerr angle can be written as a function of the transverse optical conductivity, which vanishes in systems with time reversal symmetry. Nevertheless, if the system is nonmagnetic and inversion symmetry is absent, a nonlinear Kerr effect is allowed by symmetry, opening new routes for the understanding of the fundamental features of quantum materials.

Throughout this talk, we investigate several model and realistic systems to show that magneto-optics can probe an intimate connection between the second order conductivity and the electric-induced magnetization of non-centrosymmetric systems without magnetism. In the d.c. limit, we also obtain a general identity that demonstrates that the non-equilibrium orbital magnetization and the Berry curvature dipole are companion phenomena in those materials, even in the absence of spin-orbit coupling. Finally, we compare the Kerr efficiencies obtained in our simulations with the literature, concluding that the nonlinear Kerr effect suggested here can be used to detect the orbital accumulation in light materials.