Driving the magnetic phase transition of graphene nanoribbons with fluctuation fields and doping

Abstract

Understanding the magnetic phase transition in zigzag-edged graphene nanoribbons has attracted considerable interest because of the unique properties generated from the quantum confinement and interference. However, it would be extremely difficult to experimentally integrate these nanoribbons with an ideal graphene in microelectronic devices because of their complexity, which could thus result in unexpected characteristics. By artificially generating the fluctuation field on single-layer graphene, we theoretically show how the fluctuation amplitude modifies the magnetic behaviors of the graphene system. It is proven that, by increasing fluctuation amplitude gradually, the magnetic correlated two edge state presents two typical oscillation behaviors between the antiferromagnetic and the ferromagnetic state depending on the nanoribbon width and doping concentration and then reaches the ground state of paramagnetism by further increasing the fluctuation amplitude. These findings not only uncover the influence of fluctuation on the intrinsic magnetic behaviors of nanoscale graphene ribbons, but also demonstrate effective control using external architecture that could be realized by artificial fabrication.