Substrate effects: Disappearance of adsorbate-induced magnetism in graphene

In this theoretical work, we show that substrates play key roles in the properties of layered systems such as graphene by focusing on magnetic properties associated with adsorbates. Local magnetic moments formed in fluorinated and hydrogenated graphene layers are quenched when they are deposited on a copper substrate due to several interconnected effects: doping by the substrate, increased structural distortion, and broadening of the defect states. We find that these effects contribute in different degrees to the changes in the structural, electronic and magnetic properties of the system and that they vary between adsorbates. The most important factor in the disappearance of magnetism in the functionalized graphene is shown to be the formation of metal-carbide bonds and the subsequent broadening of the impurity states that erases their spin splitting. We show that interactions with the substrate and the formation of local magnetic moments can be modified using multiple layers of graphene.