Structural, electronic and magnetic properties of the H- passivated armchair MoSe2 nanoribbons with the periodic vacancy

Under the generalized gradient approximation (GGA), we have performed the spin-polarized first-principles calculations to systematically investigate structural, electronic and magnetic properties of the hydrogen passivated armchair MoSe2 nanoribbon (H-11-AMoSe(2)NR) with the periodic vacancy near the center of the nanoribbon. The results show that the formation of the single Se-vacancy is easier than those of others. For the cases of Se-vacancy, Se-2-and MoSe-divacancy, an indirect-direct gap transition takes place along with the tunable band gap but do not induce any magnetic moment. However, for the case of MoSe2-triple vacancy, the system still remains non-magnetic indirect gap semiconductor with a smaller band gap of 0.108 eV. The calculated band gaps are 0.412, 0.447, and 0.091 eV for the Se-vacancy, Se-2-, and MoSe-divacancy, respectively, which show great feasibility in the optoelectronics. In addition, Mo-vacancy induces a remarkable spin polarization and magnetic moments concentrated on the atoms around the Mo-vacancy, which suggests such vacancy-defective H-AMoSe(2)NR can be used in spintronics and nanomagnets.