Single 3<i>d</i>transition metal atoms on multi-layer graphene systems: electronic configurations, bonding mechanisms and role of the substrate

Abstract

The electronic configurations of Fe, Co, Ni, and Cu adatoms on graphene and\ngraphite have been studied by x-ray magnetic circular dichroism and charge\ntransfer multiplet theory. A delicate interplay between long-range interactions\nand local chemical bonding is found to influence the adatom equilibrium\ndistance and magnetic moment. The results for Fe and Co are consistent with\npurely physisorbed species having, however, different 3$d$-shell occupancies on\ngraphene and graphite ($d^{n+1}$ and $d^n$, respectively). On the other hand,\nfor the late 3$d$ metals Ni and Cu a trend towards chemisorption is found,\nwhich strongly quenches the magnetic moment on both substrates.\n