Theoretical exploration on the electronic and magnetic properties of (FeCp)n – (n = 1, 2) ligand-functionalized graphene

Abstract

Using first principles calculations, we systematically studied the electronic and magnetic properties of half sandwich organometallic ligand-functionalized single layer graphene, (FeCp)_n@SLGs (n = 1, 2), with different adsorption sites and coverage concentrations. Our results show that all the (FeCp)_n@SLGs are quite stable having high binding energies. Except the nonmagnetic FeCp@G₄₄-S₁, all the complexes are found to be robust ferromagnets. In particular, the magnetic moments of (FeCp)₂@G₃₃-D₁, (FeCp)₂@G₃₃-D₂, (FeCp)₂@G₃₃-D₃ and (FeCp)₂@G₄₄-D₁ per unit cell are as large as 2.0 μ_B, 1.64 μ_B, 2.0 μ_B and 1.30 μ_B, respectively. Among the studied systems, spin polarized band gaps are opened in the Dirac points of FeCp@G₃₃-S, (FeCp)₂@G₃₃-D₁, (FeCp)₂@G₄₄-S₂, (FeCp)₂@G₄₄-S₃, and (FeCp)₂@G₄₄-D₅, in which (FeCp)₂@G₃₃-D₁ is transformed into an intrinsic semiconductor. Moreover, displacing Fe by Co or Ni element is found to induce an increasement in magnetic moment or induce a transition from metal to half metal.