Locally Induced Spin States on Graphene by Chemical Attachment of Boron Atoms.

Pristine graphene is known to be nonmagnetic due to its π-conjugated electron system. However, we find that localized magnetic moments can be generated by chemically attaching boron atoms to the graphene sheets. Such spin-polarized states are evidenced by the spin-split of the density of states (DOS) peaks near the Fermi level in scanning tunneling spectroscopy (STS). In the vicinity of several coadsorbed boron atoms, the Coulomb repulsion between multiple spins leads to antiferromagnetic coupling for the induced spin states in the graphene lattice, manifesting itself as an increment of spin-down state at specific regions. Experimental observations and interpretations are rationalized by extensive density functional theory (DFT) simulations.