Investigation on the Non-trivial Photoluminescence in 2D Antiferromagnetic Layers*

Two-dimensional (2D) magnetic systems have attracted intense attention due to potentially applications in low-dimensional spintronic and magnetic devices. Recently, we observe a non-trivial photoluminescence in metal phosphorus chalcogenides, which are 2D antiferromagnetic materials. Multiple photoluminescence peaks are observed and some of them show a strong dependence on the excitation-wavelength and temperature in both the bulk and few-layer cases, which are different from the emission in conventional 2D semiconductors. A rational model based on the special electronic structures and transitions of the materials is proposed to explain this phenomenon. Our studies reveal the intrinsic electronic and magnetic properties in 2D crystals, and suggest the potential functionalities and applications of 2D magnetic layers.