  We perform first-principles calculations based on density functional theory
to study quasi one-dimensional edge-passivated (with hydrogen) zigzag graphene
nanoribbons (ZGNRs) of various widths with chemical dopants, boron and
nitrogen, keeping the whole system isoelectronic. Gradual increase in doping
concentration takes the system finally to zigzag boron nitride nanoribbons
(ZBNNRs). Our study reveals that, for all doping concentrations the systems
stabilize in anti-ferromagnetic ground states. Doping concentrations and dopant
positions regulate the electronic structure of the nanoribbons, exhibiting both
semiconducting and half-metallic behaviors as a response to the external
electric field. Interestingly, our results show that ZBNNRs with terminating
polyacene unit exhibit half-metallicity irrespective of the ribbon width as
well as applied electric field, opening a huge possibility in spintronics
device applications.

Materials Science;Mesoscale and Nanoscale Physics