Density functional study on ferromagnetism in (Al, Fe)-codoped 4H-SiC

The electronic structure and magnetic properties of (Al, Fe) codoped 4H-SiC have been systematically studied by first principles calculations. The most energetically favorable structures in fourteen possible atomic geometries with deferent Al-Fe bondings were determined. Al dopant alone does not introduce any spin-polarization, whereas (Al, Fe) codoped 4H-SiC can induce spin-polarization. The local magnetic moment in (Al, Fe) codoped 4H-SiC is mainly contributed by Fe-3d orbitals. Ferromagnetism order is the preferred ground state and the interaction between the local moments is activated through holes induced by Fe doping via a Fe:3d-C:2p-Fe:3d coupling chain in short Fe-Fe separations.