Revealing the three-state nematicity in atomically-thin antiferromagnetic NiPS3 via magneto-optical effect

Nickel phosphorus trisulfide (NiPS3), a van der Waals (vdW) 2D antiferromagnet, has captivated enormous attention for its intriguing physics in recent years. However, despite its fundamental importance in physics of magnetism and promising potential for technological applications, the study of magnetic domains in NiPS3 down to atomically thin is still lacking. Here, we report the layer-dependent magnetic characteristics and magnetic domains within antiferromagnetic NiPS3 by employing linear dichroism (LD) combined with polarized microscopy, spin-correlated photoluminescence (PL), and Raman spectroscopy. Our results reveal the existence of the paramagnetic-to-antiferromagnetic phase transition in bulk to bilayer NiPS3 with stronger spin fluctuation in thinner NiPS3. Furthermore, our study identifies three distinct antiferromagnetic domains within atomicallythin NiPS3 and captures the thermally-activated domain evolution. Our findings provide crucial insights for the development of antiferromagnetic spintronics and related technologies.