Glassy ferromagnetism in Al-doped 4H-SiC: Al_(Si)-V_C complexes

摘要

The recent observed glassy ferromagnetism in Al-doped 4H-SiC is investigated using first principles calculations. We find that the formation energy of VC is significantly reduced by Al atoms doped in SiC. The Al _(Si)-VC complex induces a half-filled narrow a1 level in the band gap and contributes a net local moment of 1 μB. The exchange parameter J can be either positive or negative along different directions. Both the strong anisotropy of J and the correlation effects of the a1 level can lead to a glassy ferromagnetism in Al-doped 4H-SiC.