Semiconducting to half-metallic to metallic transition on spin-resolved zigzag bilayer graphene nanoribbons

Our first-principles calculations show that the electronic properties of spin-resolved zigzag bilayer graphene nanoribbons (ZBGNRs) of antiferromagnetic edges are highly sensitive to the interlayer distance between nanoribbons. The energy gap of the antiferromagnetic ZBGNR decreases and the semiconducting ZBGNR finally becomes a metal with decreasing interlayer spacing. Coupling with a transverse electric field, the ZBGNR exhibits a semiconducting to half-metallic to metallic transition via interlayer distance compression. The charge redistribution of spin-up and spin-down and the change of the density of states on the edge atoms, which are driven by the coupled effect of nanomechanical compression and the electric field, contribute to the exceptional modification on the band structure of the ZBGNR.