▎ 摘　　要

Here we discuss the possibility of modulating energy gaps of graphene nanoribbon bilayers, with zigzag edges, by applying electric fields. The system is disposed in the Bernal configuration and is described by a Hubbard Hamiltonian. We follow a Hartree-Fock mean-field theory to calculate the electronic properties of the system. Under the action of a transversal electric field, half-metallicity is found: One of the spin bands increases the gap energy as the intensity of the field is increased whereas the other decreases until achieving a null gap. For a particular electric field range, the system exhibits metallic and semiconducting features depending on the spin band. Half-metallicity is enhanced due to an extra effect for the bilayer system: The presence of a robust plateau-like in the gap versus field intensity diagram, for an intermediate energy gap value of the semiconducting band. The correlation of the gap plateau with local magnetizations and charge numbers in the two layers is investigated. Further applied gate voltages on the ribbons are considered to investigate the possibilities of getting new physical responses for tilted electric field configurations. Possible spintronic applications can be driven based on the differential spin-band features achieved.