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

Abstract

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 (T C ), which emphasizes the urgent need to design high-temperature 2D ferromagnets. Herein, we predict two stable Kagome-latticed Ti 3 X 4 (X = S or Se) monolayers using first-principles calculations and investigate their stability, electronic structures, and magnetism. The Ti 3 S 4 monolayer is a robust FM bipolar magnetic semiconductor with a band gap of 0.41 eV, and the Ti 3 Se 4 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 Ti 3 S 4 and Ti 3 Se 4 monolayers exhibit above-room-temperature T C s 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.