Layer-Dependent Magnetism in Two-Dimensional Transition-Metal Chalcogenides M _nT_{n + 1}(M = V, Cr, and Mn; T = S, Se, and Te; and n = 2, 3, and 4)

Low-dimensional magnetic materials with high stabilities and outstanding magnetic properties are essential for the next generation of spintronic devices. We will discuss the intrinsic magnetism in two-dimensional (2D) transition-metal chalcogenides MnTn + 1 (M = V, Cr, and Mn; T = S, Se, and Te; and n = 2, 3, and 4) in which many ferromagnetic half-metals and semiconductors were discovered, and some of them were dynamically stable. In particular, the dependence of the electronic structure and magnetism on the number of layers is discussed. Compared with the corresponding MT2 of the monolayer limit, that is, the well-known transition-metal dichalcogenides, the essential charge imbalance between the metal ion layers would influence the molecular orbital states, which leads to rich and subtle electronic and magnetic properties. Our findings not only enrich the family of 2D transition-metal ferromagnets but also open up avenues for the design and synthesis of other novel 2D multilayer magnets.