Stacking stability, emergence of magnetization and electromechanical nanosensing in bilayer graphene nanoribbons.

We study the electronic and magnetic structures of bilayer graphene nanoribbons (BGNRs) beyond the conventional AA and AB stackings, by using density functional theory within both local density and generalized gradient approximations (LDA and GGA). Our results show that, irrespective of the method chosen, stacking arrangements other than the conventional ones are most stable, and result in significant modification of BGNR characteristics. The most stable bilayer armchair and zigzag structures with a width of ~1 nm are semiconducting with band gaps of 0.04 and 0.05 eV, respectively. We show mechanical shift evolution of magnetic states and the emergence of magnetization upon mechanical deformation in bilayer zigzag GNRs. Band gap dependence on mechanical shift can be used to design accurate nanosensors.