First-principles study the single-layer transition metal trihalide CrXSe (X = Sn, Ge, Si) as monolayer ferromagnetic semiconductor.

Layered transition metal trihalides ABX are promising candidate materials for monolayer magnets. In this paper, we investigated single-layer CrXSe (X  =  Sn, Ge, Si) as monolayer ferromagnetic semiconductors (FMS). Firstly, our calculated interlayer binding energies and mechanical properties demonstrate the feasibility of obtaining the free-standing monolayer CrXSe from the layered van der Waals crystal CrXSe via mechanical exfoliating method.