Coupling of magnetic edge states in Li-intercalated bilayer and multilayer zigzag graphene nanoribbons

Electronic and magnetic properties of Li-intercalated bilayer zigzag graphene nanoribbons (ZGNRs) are studied by the spin density functional method. The configuration with antiferromagnetic (AFM) coupling of the edge states between two nanoribbon layers is found most stable. The energy differences between the ferromagnetic states and AFM states increase as the width of the graphene nanoribbon increases. Further calculations show that Li-intercalated trilayer and tetralayer ZGNRs also favor the AFM coupling of the edge states. Such "superlattice" structure formed with spin magnetic edge states are potentially useful for spintronics applications.