title: Spin-polarized density functional investigation into ferromagnetism in C-doped (ZnO)n clusters; n = 1-12, 16.
abstract: We investigate the ferromagnetism in ZnO clusters due to vacancy defects and C impurities doped at substitutional O or Zn sites, and interstitial sites. The total energy calculations suggest C at the O site is more stable than that at the Zn site in ZnO clusters. The total magnetic moments of Zn(n)O(n-m)C(m) clusters are 2.0 μ(B)/C. However, when two C atoms are bonded to the same Zn atom they interact antiferromagnetically and the total magnetic moment becomes less than 2.0 μ(B)/C. The interstitial C defects in ZnO clusters induce small magnetic moments. The combination of substitutional and interstitial C defects in ZnO clusters leads to magnetic moments of 0.0-2.0 μ(B)/C. The presence of vacancy defects in addition to substitutional C defects gives magnetic moments of greater than 2.0 μ(B)/C. These results suggest that the experimentally observed sample dependence of magnetic moments in ZnO systems is largely due to the different concentrations of substitutional and interstitial C impurities and the presence of vacancy defects in ZnO samples prepared under different growth conditions.
authors.affiliation: Department of Physics, Punjab Technical University, Jalandhar, Punjab 140104, India. dr.hitesh.phys@gmail.com
authors.forename: Hitesh
authors.initials: H
authors.lastname: Sharma
authors.forename: Ranber
authors.initials: R
authors.lastname: Singh
mesh_terms: D002244:Carbon / Q000737:chemistry*; D003198:Computer Simulation; D008280:Magnetics / Q000379:methods*; D008956:Models, Chemical; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D002244:Carbon; D015034:Zinc Oxide