Spin-dependent electronic transport properties of transition metal atoms doped α-armchair graphyne nanoribbons

Spin-dependent electronic transport properties of single 3d transition metal (TM) atoms doped alpha-armchair graphyne nanoribbons (alpha-AGyNR) are investigated by non-equilibrium Green's function (NEGF) method combined with density functional theory (DFT). It is found that all of the impurity atoms considered in this study (Fe, Co, Ni) prefer to occupy the sp-hybridized C atom site in alpha-AGyNR, and the obtained structures remain planar. The results show that highly localized impurity states are appeared around the Fermi level which correspond to the 3d orbitals of TM atoms, as can be derived from the projected density of states (PDOS). Moreover, Fe, Co, and Ni doped alpha-AGyNRs exhibit magnetic properties due to the strong spin splitting property of the energy levels. Also for each case, the calculated current-voltage characteristic per super-cell shows that the spin degeneracy in the system is obviously broken and the current becomes strongly spin dependent. Furthermore, a high spin-filtering effect around 90% is found under the certain bias voltages in Ni doped alpha-AGyNR. Additionally, the structure with Ni impurity reveals transfer characteristic that is suitable for designing a spin current switch. Our findings provide a high possibility to design the next generation spin nanodevices with novel functionalities.