Vacancy Defects Induced Magnetism in Armchair Graphdiyne Nanoribbon

Spin-polarized electronic and transport properties of Armchair GraphdiyneNanoribbons (A-GDYNR) with single vacancy (SV), two types of configurations fordouble vacancy (DV1, DV2) and multi vacancy (MV) defects are studied by nonequilibriumGreen’s function (NEGF) combined with density functional theory (DFT).The results demonstrate that the A-GDYNR with the SV has the lowest formationenergy and the most energetically favorable. The SV induces a 2.08 μB magneticmoment while the DV2 possess no magnetism into A-GDYNR. Analyzing the bandstructures shows that the perturbation in A-GDYNR caused by the SV, DV1 and MVbreaks the degeneracy and appears new bands around the Fermi level which indicate astrong spin splitting. Moreover, using density of states (DOS) analysis, it is illustratedthat the appeared flat bands correspond to the localized states which mainly contributeby the carbon atoms near the vacancies. The calculated current-voltage characteristicsfor A-GDYNR with the SV, DV1, and MV reveal that the spin degeneracy is obviouslybroken. As well, a high spin-filtering efficiency around 90% is found at the bias voltageof 0.3V for A-GDYNR with the SV. Our findings illustrate that we can obtain AGDYNRswith especial magnetic properties by removing carbon atoms from AGDYNR.