Ti-doped AlN potential n-type ferromagnetic semiconductor: Density functional calculations

The magnetism and the electronic structures of Ti-doped AlN are studied by the first-principles calculations. It is found that Ti prefers to substitute Al site in AlN host, and this doped configuration favors the ferromagnetic ground state. The magnetic moment of the supercell containing single TiAl is 1.00 μB. Electronic structures suggest magnetic moments mainly come from the doped Ti atom, Ti-doped AlN is n-type ferromagnetic semiconductor and the ferromagnetism can be explained by double-exchange mechanism. For O and Ti co-doped AlN, calculations show ON defect would induce magnetic moments increasing and change Ti-doped AlN from semiconductor to metal.