Magnetic two-dimensional chromium trihalides: structure, properties and modulation

The unique optical and electrical properties of two-dimensional (2D) materials provide a platform for novel van der Waals (vdW) heterojunction devices but the investigation of 2D magnetism is still limited. Recently, the emergence of long-range magnetic order atomically thin crystals expands 2D family, providing possibilities for the study of low-dimensional spin behavior and novel spintronics devices. As a specific member of magnetic van der Waals family, chromium trihalides (CrX 3 , X = Cl, Br, I) stimulated intensive interests on account of the newfangled magnetic properties. In this review, we briefly introduce the crystal structures, magnetism of the bulk and synthetic methods of 2D CrX 3 . Subsequently, the physical properties in atomically thin limit and magnetism manipulated by external field are presented. Next, some novel physical phenomena in CrX 3 heterojunctions are discussed. Finally, the challenges and future directions are proposed. We focus on the intriguing physical phenomena in 2D magnetic CrX 3 by combining related theoretical calculations and experimental results, providing a perspective on these emerging materials. Graphical abstract