Theoretical understanding of magnetic and electronic structures of Ti3C2 monolayer and its derivatives

• We explored the origin of magnetism in Ti3C2.
• We demonstrated the roles of surface modification on the electronic and magnetism of Ti3C2.
• The Curie temperature of magnetism is generally reduced with the surface modification.

First-principles calculations were performed to investigate the electronic and magnetic properties of Ti3C2 monolayer and its derivatives. We found that pristine Ti3C2 monolayer acts as a magnetic metal, and magnetic moments come from Ti2+ ions at two sides. Through doping nitrogen atoms, the spin moments is significantly reduced. On other hand, when two surfaces of Ti3C2 monolayer are saturated by external groups, the magnetism will be spontaneously annihilated. Even for the saturation of one side, we also found that the magnetism of Ti3C2Y (Y is O and OH) monolayer is removed because of the invalidation of stoner instability. More importantly, we explored that both doping and surface modification will reduce the Curie temperature of Ti3C2 monolayer. Therefore, our results shed a light on the way to get high-temperature magnetism in Ti3C2 monolayer.