Effects of Mono-Vacancies of Oxygen and Manganese on the Properties of the MnO(2)/Graphene Heterostructure

The effects of the monovacancies of oxygen (V(O)) and manganese (V(Mn)) on the structural and electronic properties of the 1T–MnO(2)/graphene heterostructure are investigated, within the framework of density functional theory (DFT). We found that the values of the formation energy for the heterostructure without and with vacancies of V(O) and V(Mn) were −20.99 [Formula: see text] , −32.11 [Formula: see text] , and −20.81 [Formula: see text] , respectively. The negative values of the formation energy indicate that the three heterostructures are energetically stable and that they could be grown in the experiment (exothermic processes). Additionally, it was found that the presence of monovacancies of V(O) and V(Mn) in the heterostructure induce: (a) a slight decrease in the interlayer separation distance in the 1T–MnO(2)/graphene heterostructure of ~0.13% and ~1.41%, respectively, and (b) a contraction of the (Mn−O) bond length of the neighboring atoms of the V(O) and V(Mn) monovacancies of ~2.34% and ~6.83%, respectively. Calculations of the Bader charge for the heterostructure without and with V(O) and V(Mn) monovacancies show that these monovacancies induce significant changes in the charge of the first-neighbor atoms of the V(O) and V(Mn) vacancies, generating chemically active sites (locales) that could favor the adsorption of external atoms and molecules. From the analysis of the density of state and the structure of the bands, we found that the graphene conserves the Dirac cone in the heterostructure with or without vacancies, while the 1T–MnO(2) monolayer in the heterostructures without and with V(O) monovacancies exhibits half-metallic and magnetic behavior. These properties mainly come from the hybridization of the 3d–Mn and 2p–O states. In both cases, the heterostructure possesses a magnetic moment of 3.00 μ(β)/Mn. From this behavior, it can be inferred the heterostructures with and without V(O) monovacancies could be used in spintronics.