Vacancy Defects Induced Magnetism in Armchair Graphdiyne Nanoribbon

Document Type : Articles

Authors

1 Department of Electrical Engineering, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran

2 Faculty of Electrical, Biomedical and Mechatronics Engineering, Qazvin BranchIslamic Azad UniversityQazvinIran

Abstract

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.

Keywords