High temperature ferromagnetism of (Co,N)-codoped 3C-SiC investigated by density functional theory calculations

Abstract

Abstract The electronic structure and magnetic properties of (Co,N)-codoped cubic silicon carbide (3C-SiC) are investigated by performing first-principles calculations based on density functional theory. Our studies suggest that the CoSi impurities introduce magnetic moments due to the unpaired d electrons, and the C atoms play the important roles for mediating the ferromagnetic (FM) coupling between Co impurities by p-d exchange interaction. The magnetic moments introduced by the CoSi-NC defect complexes are much more energetically favourable than those of the CoSi impurities in 3C-SiC. The lattice distortion contributed by CoSi impurities is partially compensated by substituting N atoms at the nearest neighboring carbon sites, which results in the formation energy of the defect complex CoSi-NC is significantly decreased. The Curie temperature of CoSi and CoSi-NC doped 3C-SiC is predicted to reach the room temperature.