Spin polarization of single-layer graphene epitaxially grown on Ni(111) thin film

Entani, Shiro; Kurahashi, Mitsunori*; Sun, X.*; Yamauchi, Yasushi*

The spin-resolved electronic structure of graphene on Ni(111) was investigated using spin-polarized metastable deexcitation spectroscopy (SPMDS). Graphene was grown epitaxially on a Ni(111) single-crystalline surface using the ultra high vacuum chemical vapor deposition technique with benzene vapor as a precursor. At 50 L (510 Torr sec), a single epitaxial layer of graphene was formed, but no further growth was observed at higher exposure. The spin-summed spectrum of graphene/Ni(111) had a new peak at the Fermi level and three weak features corresponding to the molecular orbitals of graphene. Spin asymmetry analysis of the SPMDS spectra revealed that the spin polarization of the electronic states shown by the new peak was parallel to the majority spin of the Ni substrate. The appearance and spin polarization of the new electronic states are discussed in terms of the hybridization of graphene pi orbitals and Ni d orbitals.