Density Functional Theory Prediction of Room-Temperature Two-Dimensional Ferromagnetic Materials for Applications as Spintronic Devices

Currently, two-dimensional (2D) ferromagnetic (FM) materials have become one type of promising spintronic devices. However, the practical applications of 2D FM materials are severely hampered by low Curie temperature (TC), which emphasizes the urgent need to design high-temperature 2D ferromagnets. Herein, we predict two stable Kagome-latticed Ti3X4 (X = S or Se) monolayers using first-principles calculations and investigate their stability, electronic structures, and magnetism. The Ti3S4 monolayer is a robust FM bipolar magnetic semiconductor with a band gap of 0.41 eV, and the Ti3Se4 monolayer is a FM half metal (HM) with a band gap in the spin-down channel of 0.44 eV. Monte Carlo simulations indicate that both Ti3S4 and Ti3Se4 monolayers exhibit above-room-temperature TCs of 382 and 436 K, respectively. Interestingly, the FM–antiferromagnetic transition and HM-to-semiconductor transition are found under tensile strains. Our findings propose an effective platform to design promising FM candidates for potential spintronic devices.