Magnetism of graphene quantum dots

Abstract Graphene quantum dots with the high edge-to-area ratio have possibly substantial spin polarized edge states, which theoretically can generate fascinating magnetic properties. The magnetism of well-defined graphene quantum dots is relevant with both fundamental physics and potential applications in spintronics. In this article, we report the intrinsic magnetism of graphene quantum dots. Our graphene quantum dots with the average diameter of ca. 2.04 nm show the purely Curie-like paramagnetism with the local moment of 1.2 μ B at 2 K. It is proposed that the magnetic moment of graphene quantum dots may mainly origin from the residual zigzag edges passivated by hydroxyl groups. The ratio of nonmagnetic graphene quantum dots is approximately 6/7, with most of the magnetic edge states suppressed by edge defects and/or edge reconstruction arising from the high-temperature annealing. Our study experimentally unveils the intrinsic magnetism of graphene quantum dots.