Observation of the second harmonic generation in layered antiferromagnet CuCrP₂S₆

In van der Waals antiferromagnets, a variety of magnetic structures are realized, leading to unique magnetic and optical properties. Among them, second harmonic generation (SHG) is a powerful probe of the spatial inversion symmetry breaking as well as the complex magnetic symmetry.

Here, we report the observation of SHG in exfoliated van der Waals antiferromagnet CuCrP₂S₆ (CCPS). Structural phase transition from centrosymmetric to non-centrosymmetric crystal structure and an antiferromagnetic phase transition, which have been reported in the previous studies of bulk CCPS [1], was successfully observed as the intensity/polarization-dependent-pattern changes of SHG. Characteristic behaviors of the SHG signal and their possible origins will be also discussed in the presentation.

[1] C. C. B. Park et al. Adv. Electron. Mater. 2101072 (2022)