Effect Of Magnetic Atom Doping On Spin Properties Of Graphene/Graphyne-like Nanoribbons

With the continuous development of chip technology,the traditional silicon-based electronic devices can meet the needs of people for electronic equipment in the future only by shrinking the volume and increasing the integration.When the size of the traditional silicon-based electronic device is reduced to the micro scale,the quantum effect inside the electronic device will greatly affect its performance.The molecular spintronics based on molecular spintronics can effectively solve this problem.The interaction between spin electrons is 103 times weaker than that between ordinary charges,so the energy consumption and stability of molecular spintronics are incomparable to those of ordinary micro/molecular electronics.On the choice of molecular spintronics materials,graphene has excellent carrier mobility,conductivity and other properties due to its small thickness(only single atom thickness).Graphyne is a new type of carbon nanostructure material.Its structure has many excellent characteristics such as large conjugated system,wide surface spacing,stable chemical properties and semiconductor properties.For graphene-like or graphyne-like nanoribbons,the electron occupation of the edge carbon atoms controls the spin polarization transmission,so it is easier to fabricate molecular spintronic devices with specific functions by various ways such as doping defects and boundary modification.In this paper,the effect of magnetic atoms doping on the spin properties of graphene/graphyne-like nanoribbons was investigated by using the first-principles density functional theory(DFT)and non-equilibrium Green’s function(NEGF).The research work includes the following three aspects.(1)The influence of three magnetic atoms(Fe,Co,Ni)doped into nitrogen-containing zigzag graphyne-like nanoribbons(N-ZGyNRs)on the spin and electrical properties of the structure.The results show that doping different magnetic atoms can effectively regulate the spin properties and electrical properties of the original N-ZGyNR,so as to obtain the molecular spintronics with the desired performance.(2)The effects of three magnetic atoms(Fe,Co,Ni)doped into the double-layer zigzag graphene-graphyne nanoribbon(d-pure-ZG-GyNRs)double-probe structure on its spin properties and spin electron transport were investigated.The results show that the double-probe structure of d-M-ZG-GyNRs doped with different magnetic atoms(M)has interlayer coupling effect,which has an enhanced effect on the spin polarization current of all structures.The spin properties of d-Fe-ZG-GyNRs and d-Co-ZG-GyNRs show obvious spin splitting,and d-Fe-ZG-GyNRs show obvious spin filtering effect,which provides a new prospect for the research and design and application of spin filters.It is also found that the total maximum power Pmax(sum)of d-M-ZG-GyNRs is higher than that of d-pure-ZG-GyNRs,which provides ideas for improving the performance of molecular spintronics.(3)Magnetic cobalt atoms were doped into single-layer serrated graphene-graphyne nanoribbons(Co-ZG-GyNRs)to form a double-probe structure with a certain angle θ(Co-ZG-GyNRs-θ)between the central scattering region and the left and right electrode regions,and the spin electron transport properties were observed.The results show that there is a spin filtering effect in Co-ZG-GyNRs-θ where the lower spin polarization current is completely suppressed.At the same time,the coupling effect of this structure makes the upper spin polarization current increase with the increase of θ.Therefore,this structure can provide some ideas for the design of spin filters and the improvement of the performance of molecular spintronics.