Theoretical Study Of Transition Metal Doped Single Layer Molybdenum Disulfide And Black Phosphorus

The considerable direct band gap of the graphene-like MoS2 and black phosphorus make them adaptable to applications in transistors,photo-emitting devices,lubricants,catalysis,hydrogen storage,Li-ion batteries,etc.However,both single-layer MoS2 and black phosphorus are nonmagnetic,which limits their applications in spintronic devices.On the other hand,due to the fact that the Mo atoms are in the middle of the sandwich structure,there is no catalytic activity on the van der Waals surface of monolayer MoS2.It is found that the impurity atoms can change their magnetic and catalytic properties.In this paper,the transition metal atoms were doped into single layer MoS2 and black phosphorus to improve their magnetic properties,and the catalytic activity of van der Waals surface of monolayer MoS2 in the presence of CO oxidation.In addition,the electronic structures of the tetrahedral 3d metal clusters embedded in monolayer MoS2 were investigated.All the researches were carried out using the first-principles calculation based on density functional theory(DFT).Firstly,the electronic structures and magnetic properties of Re atom doped single-layer MoS2 were investigated.Four doping configurations were considered,and all of them show large spin polarization.The magnetic moment of substitution doping is 0.68?B,and the magnetic moments of three adsorption doping configurations are all 3?B.It is found that the spin polarization is caused by excess electrons of Re atom in substitution doping configuration,and for the adsorption mode,the single occupation of impurity state is the reason of its spin polarization.Secondly,the electronic structure properties of tetrahedral 3d transition metal cluster(TM4)doped monolayer MoS2 were studied.Electrons transfer from the transition metal atoms to the monolayer MoS2,which results in the Fermi level enter into the band gap.Ti4,V4,Mn4,Fe4,Co4,Ni4,Cu4 clusters doped MoS2 systems induce a large obital polarization,resulting in a larger magnetic moment,in them,V4,Mn4,Cu4 clusters doped monolayer MoS2 also polarized the 4d orbitals of near Mo atoms.Thirdly,the catalytic activity for CO oxidation of monolayer transition metal atoms adsorbing monolayer MoS2 surface(TM/MoS2)were investigated.It is found that the stability of monolayer transition 3d metal atoms adsorbing monolayer MoS2 is higher than that of single transition metal atom adsorbing monolayer MoS2.When a CO molecule is adsorbed on the surface of Mn/MoS2,the interaction between C atom and transition metal atom is the strongest,and the C-O bond of the CO molecule is the longest.This makes it easier to open the C-O bond of CO molecule,and facilitates the oxidation reaction of CO.Finally,the electronic structures and magnetic properties of 3d transition metal atom doping monolayer black phosphorus were studied.The magnetic moments of Sc,Co,Cu,Zn atoms doping single-layer black phosphorus are zero,and the magnetic moments are produced after the doping of other 3d metal atoms.The magnetic moment of Mn atom doped monolayer black phosphors is the largest in all doping systems(reaching 4.0?B).When Mn atom is doped into single-layer black phosphorus,obvious s-d electron hybridization appeared,and the 3d orbital of Mn splits into two parts.The 3dxz,3dyz and 3dx2-y2 orbitals were fully polarized,which is the main reason for its large magnetic moments.