The Evolution of Band Topology in Two-Dimensional Weyl Half-Metals.

Two-dimensional ferromagnetic Weyl half-metals that are robust against spin-orbital coupling were theoretically proposed recently, in which the nodal points and the nodal loops are protected by specific symmetries. As the symmetry of a ferromagnetic material is highly dependent on the magnetization orientation, here we predict a family of two-dimensional ferromagnetic Weyl half-metals, Mn 2 X 3 (X = S, Se, Te) monolayers, to investigate the band topology under different magnetization orientations in the presence of spin-orbital coupling. The Curie temperatures (∼1000 K) were estimated to be much higher than room temperature due to the strong double exchange interaction and the suppression of spin fluctuation for the two-sublayer structure. Taking a Mn 2 Te 3 monolayer as an example, we demonstrated the evolution of the nodal points and the nodal loops in the presence of spin-orbital coupling via manipulating magnetization orientation. Our work provides a family of high temperature two-dimensional ferromagnetic Weyl half-metals for investigating the nontrivial band topology.