Electronic and magnetic properties of F atoms adsorbed on TiO_2:Mn(001) diluted magnetic semiconductor surfaces: First-principles calculations

摘要

We performed first-principles calculations for two Mn-doped structures in which Mn atoms substitute Ti atoms to determine whether (i) it is more conducive to Mn ion doping and (ii) ferromagnetism can occur in F adsorption anatase TiO_2 surfaces. Ferromagnetic (FM) coupling is more stable than antiferromagnetic (AFM) coupling for all doping configurations as the adsorption of F atoms on the surface significantly lowers the formation energy of the TiO_2:Mn system. The magnetic moments of the Mn ions are reduced, whereas those of O atoms on the surface are increased. The magnetic moment of the O atoms is mainly derived from the spin polarization p_x and p_y orbitals. F adsorption promotes doping of Mn atoms and to a certain extent improves the stability of the structure, magnetism and metallicity.