Electric field induced modulation to the magnetic anisotropy of Fe/silicene heterostructures: First-principles study

In view of the importance of inducing magnetism and large perpendicular magnetic anisotropy in silicene, the influence of an external electric field on the magnetism and the magnetic anisotropy of the Fe(15, 18, 21 monolayers)/silicene heterostructures are investigated by using first-principles calculations. The results show that the magnetic moments and the magnetic anisotropy of the Fe/silicene heterostructures are mainly from Fe films. With increasing the thickness of Fe film, the easy magnetization axis of the Fe/silicene heterostructure changes from out-of-plane to in-plane direction. In addition, the magnetic moments in all the Fe/silicene heterostructures are insensitive to the electric field. Particularly, under the positive electric field, the perpendicular magnetic anisotropy of the Fe(15 monolayers)/silicene can be enhanced, the magnetic anisotropy of the Fe (18 monolayers)/silicene increases from in-plane magnetic anisotropy to perpendicular magnetic anisotropy, and the magnetic anisotropy of the Fe(21 monolayers)/silicene also increases although its easy magnetization axis is still along in-plane direction. The mechanism of the electric-field-driven modulation of magnetic anisotropy is mainly from the increase of the positive contribution from spin-orbit coupling interaction between opposite spin d(z2) and d(yz) orbitals of the second Fe layer from the Fe/silicene interface. Our study reveals that the perpendicular magnetic anisotropy can be achieved or enhanced by applying positive electric field if the thickness of Fe film in Fe/silicene heterostructure is suitable.