Electronic structure and magnetic ordering in gadolinium-doped AlGaN from LSDA + U calculations

摘要

We present first-principles calculations of the structural, electronic and magnetic properties of Gd-doped Al_(0.25)Ga_(0.75)N based on the density functional theory within LSDA + U schemes. It is found that Gd atom favors substituting for Al site.compared with undoped Al_(0.25)Ga_(0.75)N, the Gd-doped Al_(0.25)Ga_(0.75)N has become an indirect band gap semiconductor of reduced band gap. The magnetic moment 7.15 μB per molecule mainly comes from Gd ion with little contribution from the Ga, Al and N atoms. It is confirmed that the ferromagnetic configuration is stable for Al_(0.1875)Gd_(0.0625)Ga_(0.75)N. It is found also that there is hybridization between the forbital of the Gd atom and the p orbital of the N atom.