Tunable magnetic and electronic properties of two intrinsic half-metallic MXene monolayers Sc2Na2CNC and Sc2K2CNC

Magnetic MXenes, especially the half-metallic MXenes, are attracting increasing attention due to their unique crystal characteristics, high strength and flexibility, and then wide applications in spintronics and nanoelectronics. In this paper, two intrinsic half-metallic bimetallic MXene monolayers Sc2Na2CNC and Sc2K2CNC were predicted based on the first-principles calculations. Their half-metallicity is stable within a certain biaxial stain range. Their magnetic moments are up to 3.00 mu B per unit, which are helpful to their applications in spintronics. The half-metallicity and magnetic moments of these monolayers may be evidently improved by the positive charge states. If the charge states vary from n = 0 to n = +2, the magnetic moments of their 2 x 2 x 1 supercells will increase from 12.00 to 14.00 mu B. It was notable that the half-metallic gaps and the magnetic moments of monolayers Sc2Na2CNCF2 and Sc2Na2CNCCl2 are evidently larger than those of the monolayer Sc2Na2CNC, so the F/Cl-absorption bilaterally may improve the performances of the monolayer Sc2Na2CNC. The above magnetic moments agree well with those analyzed by the molecular orbital theory.