Laser-induced hole coherence in 2D antiferromagnet MPS₃ through spatial self-phase modulation

Transition metal phosphorus sulfides (MPS₃), a family of two-dimensional magnetic materials with a van der Waals structure, exhibit promising applications in nonlinear optical devices. The emergence of carrier coherence in MPS₃ is a fascinating topic in coherently controlling the nonlinear effect (or other novel phenomena). Herein, we systematically investigated the third-order nonlinear optical responses of MPS₃ (M = Ni, Fe, Mn) flake suspensions based on spatial self-phase modulation (SSPM) effect. The effective monolayer third-order nonlinear susceptibilities (<i>χ</i>monolayer(3)) of NiPS₃ and MnPS₃ are obtained for the first time at multiple wavelengths. Our results show that NiPS₃ has a higher <i>χ</i>monolayer(3) value (3.59 × 10^-9 e.s.u. or 5.01 × 10^-17 m²V^-2 at 405 nm excitation) than those of FePS₃ and MnPS₃. Furthermore, we laser-induced non-local hole coherence in MPS₃ based on SSPM, where the origin of excited-state holes is analyzed from electronic structures. The relationships between hole mobility <i>μ</i> _hole, effective mass <i>m</i> <i>h</i>∗, and <i>χ</i>monolayer(3) for the three materials fulfill the previous investigation results. Because laser-induced hole coherence has rarely been reported, our investigation enriches the coherent regulation of two-dimensional magnetic MPS₃ materials, enabling potential applications in all-optical devices.