Structural, electronic, and magnetic properties of the period vacancy in zigzag GaN nanoribbons

We have performed the first-principles calculations on the structural, electronic, and magnetic properties of zigzag GaN nanoribbon (ZGaNNR) with period vacancy located at different sites across the ribbon width. The results show that, the formation of the N-vacancy is easier than that of the Ga-vacancy at each equivalent geometrical site and both of them are endothermic. An inward relaxation of the three nearest Ga atoms around a N-vacancy occurs, while for the three nearest-neighbor N atoms around the Ga-vacancy, an outward relaxation occurs. Except for a typical nonedge N-vacancy, the N-, or Ga-vacancies at other sites induce magnetic moment and spin polarization implying such vacancy-defective ZGaNNRs can be useful in spintronics and nanomagnets. The magnetic moment of the N-vacancy is dependent on defect sites, while for the Ga-vacancy, it is less dependent on the defect sites. The net magnetic moment of the vacancy defective 8-ZGaNNR is mainly contributed by the atoms around a vacancy.