Vacancy Defects Induced Magnetism in Armchair Graphdiyne Nanoribbon

Spin-polarized electronic and transport properties of Armchair Graphdiyne Nanoribbons (A-GDYNR) with single vacancy (SV), two types of configurations for double vacancy (DV1, DV2) and multi vacancy (MV) defects are studied by nonequilibrium Green’s function (NEGF) combined with density functional theory (DFT). The results demonstrate that the A-GDYNR with the SV has the lowest formation energy and the most energetically favorable. The SV induces a 2.08 μB magnetic moment while the DV2 possess no magnetism into A-GDYNR. Analyzing the band structures shows that the perturbation in A-GDYNR caused by the SV, DV1 and MV breaks the degeneracy and appears new bands around the Fermi level which indicate a strong spin splitting. Moreover, using density of states (DOS) analysis, it is illustrated that the appeared flat bands correspond to the localized states which mainly contribute by the carbon atoms near the vacancies. The calculated current-voltage characteristics for A-GDYNR with the SV, DV1, and MV reveal that the spin degeneracy is obviously broken. As well, a high spin-filtering efficiency around 90% is found at the bias voltage of 0.3V for A-GDYNR with the SV. Our findings illustrate that we can obtain AGDYNRs with especial magnetic properties by removing carbon atoms from AGDYNR.