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.