Novel nonlinear magneto-optical effects in two-dimensional magnets

The interplay of polarization and magnetism in materials with light can create rich nonlinear magneto-optical (NLMO) effects and the recent discovery of two-dimensional (2D) van der Waals magnets provide unprecedented control over NLMO effects due to their superb tunability. Here, based on the computational method developed in Refs. [1, 2], we report giant NLMO effects in representative 2D magnets, including a dramatic change of second-harmonics generation (SHG) polarization direction and intensity (on/off switch) under magnetization reversal, and a 100% SHG circular dichroism effect. We further reveal that these effects could not only be used to design ultra-thin multifunctional optical devices, but also to detect subtle magnetic orderings. Remarkably, we analytically derive conditions to achieve giant NLMO effects and propose general strategies to realize them in more 2D magnets. Our work not only uncovered a series of intriguing NLMO phenomena, but also paves the way for both fundamental research and device applications of ultra-thin NLMO materials.



REFERENCES

[1] C. Wang et al., Phys. Rev. B, 96, 115147 (2017).

[2] H. Chen et al., Phys. Rev. B, 105, 075123 (2022).