Possible ferromagnetism in Li, Na and K-doped AlN: A first-principle study

The magnetic properties of Li, Na and K doped AlN are investigated using first-principle calculations within the generalized gradient approximation. The calculations show that the introduced holes by doping atoms X (X=Li, Na and K) are mainly confined to minority-spin 2p states of the N atoms. The magnetic moment induced by a doping atom X is 2.0 μB and the moment mainly comes from the 2p orbitals of the N atoms, among which the moments of the first four neighboring N atoms around the doping atom are the biggest. In X doped AlN, the magnetic coupling between the moments induced by two doping atoms X is ferromagnetic and long-ranged. The calculated DOS and spin density distribution show that origin of the ferromagnetic coupling can be attributed to the p–p hybridization interaction involving holes. - Highlights: ► Doping by alkali introduces holes in p orbitals of N. ► Induced moment comes from p orbitals. ► Coupling between moments is FM.