Origin of the ferromagnetism of transition metal (Co, Ni) Co-doped 4H-SiC from first-principles calculations

Abstract

The electronic and magnetic properties of Co, Ni, (Co, Ni), (Co, Ni, Al) and (Co, Ni, VSi) doped 4H-SiC have been calculated using the first principles method based on density functional theory. The results show that the magnetic moments can be induced by the dopant Co or Ni atom. We also found that the (Co, Ni) co-doped 4H-SiC system is ferromagnetic at room temperature, with a △EFM value of −354.3 meV. Moreover, the 3d orbitals of Co, 3d orbitals of Ni and 2p orbitals of C can induce a spin-polarized state in (Co, Ni) co-doped 4H-SiC. Furthermore, for the (Co, Ni, Al) co-doped 4HSiC system, the ferromagnetic state is more stable than the anti-ferromagnetic state, with a △EFM value of −476.7 meV. The presence of Si vacancies (VSi) weakens the ferromagnetism state of (Co, Ni, VSi) doped 4H-SiC, with a △EFM value of −232.0 meV. The present results indicate that the (Co, Ni) co-doped 4H-SiC system is a highly magnetism material.