Robust Ferromagnetism with High Curie Temperature in 2D Tri‐Layer Ti ₃ S ₂ X ₂ (X = Se/Te) Monolayer

Abstract 2D ferromagnetic (FM) semiconductors/half‐metals offer promising prospects for quantum information technologies in miniature devices. However, the low Curie temperature ( T C ) severely limits their application in spintronic devices. Here, two stable FM transition metal chalcogenides, Ti 3 S 2 X 2 (X = Se, Te) monolayers, based on first‐principles calculations are presented. It is found that the Ti 3 S 2 Se 2 monolayer is a bipolar magnetic semiconductor with an indirect bandgap of 0.094 eV, while Ti 3 S 2 Te 2 exhibits be FM half‐metallic feature. Notably, the T C s of Ti 3 S 2 Se 2 monolayer and Ti 3 S 2 Te 2 monolayer are 641 and 408 K, respectively, much higher than room temperature. Moreover, the T C s and electronic properties of both Ti 3 S 2 X 2 (X = Se, Te) monolayers can be modulated by applying biaxial strains. These promising properties make Ti 3 S 2 X 2 (X = Se, Te) monolayers ideal candidates for 2D spintronic devices.