Magnetic and electronic properties of transition metal doped aluminium nitride: Haldane’s approach combined with ab initio results

The electronic and magnetic properties of transition metal (Mn and Cr) doped Aluminium Nitride (AlN) in the wurtzite structure is studied using the single impurity Anderson model (SIAM) extended to semiconductors by Haldane. An equation of motion method based on Green’s function was used to obtain the effective spin decomposed impurity levels. The calculated electronic density of states of Mn and Cr valence orbitals exhibit half metallic properties when the impurity is strongly coupled to the host. The effect of the Coulomb correlation and orbital hybridization on the formation of a localized moment in such systems is investigated. Magnetic impurities are often responsible for the inelastic scattering of conduction electrons. For a configuration averaged random ensemble of impurities, initially non-polarized host band develops a small moment presumably due to the potential scattering.