First-principles study of the ferromagnetism of Mn-doped 3C-SiC

Abstract

The electronic structure and magnetic nature of Mn substitutional impurities (MnSi) in cubic silicon carbide (3C-SiC) are investigated based on first-principles calculations. Our studies revealed that MnSi impurity introduces a magnetic moment of 3.0 μB due to the unpaired d electrons of Mn atoms, and the surrounding C atoms play an important role for mediating the ferromagnetic (FM) coupling between MnSi impurities by p-d exchange coupling. The magnetism contributed by the defect complex (MnSi-NC) is much more energetically stable than that of the MnSi impurity in 3C-SiC. The magnetic moments arising from MnSi impurities and MnSi-NC defect complexes are found to be more energetically favorable in FM coupling than in antiferromagnetic (AFM) coupling. The Curie temperature of MnSi-NC defect complexes doped SiC system is predicted to reach the room temperature. Due to the smaller lattice distortion of the MnSi-NC defect complex in 3C-SiC, the formation energy of the MnSi-NC defect complex is significantly decreased in comparison with single MnSi impurity in 3C-SiC.