Defect influence on the electronic and magnetic properties of silver-doped (6,0) single-walled ZnO nanotubes: a first-principles study

We investigated the electronic and magnetic properties of pure and defected single-wall (6,0) chiral ZnO nanotubes. In a consecutive DFT-LSDA+U electronic structure simulation, influence on the nature and origin of ferromagnetism (FM) are studied for an Ag-doped single-walled ZnO nanotube system. The configurations with zinc host atoms replaced by silver atoms are p-type materials. For the Ag-doped ZnO nanotube (ZnONT) configurations, the energy gap decreases with the impurity concentration. The total energy calculations for Ag-doped ZnONT systems show the stability of the ferromagnetic phase. In the case of Ag doping and with Zn vacancy, the wide energy gap decrease and the total magnetic moment of this system increase by ~ 2 µ_B compared with the free vacancy case. From first-principles calculations, it shows that ZnO:Ag NT systems are semi-magnetic ferromagnetic materials, and it is a promising candidate for spintronics device applications.