Electronic structures and magnetism of diluted magnetic semiconductors Sn1−xGdxTe: A density functional theory study

The structural, energy stability, and magnetic properties of the diluted magnetic semiconductors Sn1−xGdxTe (x = 3.125 at. %, 6.25 at. %, and 12.5 at. %) were investigated based on density functional theory. The calculated lattice parameters of the Sn1−xGdxTe compounds at zero pressure and zero temperature are in very good agreement with the existing experimental data. The energy stability of different configurations was also investigated, and the results show that Gd atoms prefer to occupy the nearest neighbor positions to the next nearest. It is hopeful to obtain ferromagnetic actual samples with Gd concentration around 6.25 at. %. It also confirms that there is presence of a small ferromagnetic interaction, competitive with the main antiferromagnetic interaction. However, this ferromagnetic interaction is too weak to show global magnetic moment.