Tunable surface magnetism by gate voltage in a slab of nonmagnetic half-Heusler compound CoTiSb.

The electrical manipulation of magnetization is appealing to the relevant experiment and spintronic device. In this paper, we focus on the electrical and magnetic properties of a thin film cleaved from the nonmagnetic half-Heusler compound CoTiSb. By means of the first-principles calculations, we find that the surface of TiSb termination possesses ferrimagnetism with a magnetic moment of 0.35 (0.49) μ B per unit cell without (with) Hubbard U, which can persist below the Curie temperature of 48 (54) K. What is more, such a surface magnetism can be tuned to nonmagnetism by gate-induced hole doping with a concentration of 2.83 × 10 14 (3.55 × 10 14 ) cm -2 . This magnetic tunability of the CoTiSb slab provides a platform to realize the pseudo-spin valve with both the magnetic electrodes and nonmagnetic space layer made of the same material without hetero-interfaces.