Electronic structure and magnetism of cubic Ga1−xEuxN and Al1−xEuxN using the LSDA + U approach

First-principles calculations of the electronic structure and magnetic interaction of substitutional europium rare-earth impurity in cubic GaN and AlN have been performed using density-functional theory within the LSDA + U approach (local spin-density approximation with Hubbard-U corrections). The LSDA + U method is applied to the rare-earth 4ƒ states. The Ga1−xEuxN and Al1−xEuxN are shown to be semiconductors, where the filled ƒ states are located in the valence bands and the empty ones in the conduction bands. Magnetic interaction of the rare-earth ion with the host states at the valence and conduction band edges has been investigated and found to be relatively weak in comparison with Mn impurities. Further, the filled and empty ƒ states are also shown to shift downwards and upwards in the valence and conduction bands, respectively, with increasing the U potentials.