A first-principles study of electronic and magnetic properties of 4d transition metals doped in Wurtzite GaN for spintronics applications

We studied the electronic and magnetic properties of wurtzite GaN (w-GaN) doped with different concentrations of the 4d transition metal ions Nb, Mo, and Ru. We incorporated spin-polarized plane-wave density functional theory within an ultrasoft pseudopotential formalism. The 4d transition metals were doped at different geometrical sites to determine the geometry with the lowest total energy and the one that induced the largest magnetization. A spin-spin interaction study was performed to determine whether the doped compound was ferromagnetic or antiferromagnetic. The origin of magnetization in the transition metal-doped w-GaN compounds is due to the p-d hybridization of the nitrogen and 4d transition metals. From the bulk modulus results, we inferred that the structural integrity is preserved under compressive loads after doping w-GaN with these 4d transition metal ions. Our results indicate that these compounds can be used in spintronic applications.