A possible approach to achieve quasi-freestanding graphene on a substrate for technological purpose is the intercalation of alkali metal atoms. Cs intercalation between graphene and Ni(111) therefore is investigated using density functional theory, incorporating van der Waals corrections. It is known that direct contact between graphene and Ni(111) perturbs the Dirac states. We find that Cs intercalation restores the linear dispersion characteristic of Dirac fermions, which agrees with experiments, but the Dirac cone is shifted to lower energy, i.e., the graphene sheet is n-doped. Cs intercalation therefore decouples the graphene sheet from the substrate except for a charge transfer. On the other hand, the spin polarization of Ni(111) does not extend through the intercalated atoms to the graphene sheet, for which we find virtually spin-degeneracy.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: Assistance provided by M. Upadhyay-Kahaly and T. P. Kaloni is greatly appreciated. This publication was made possible by a National Priorities Research Program grant (NPRP 7-665-1-125) from the Qatar National Research Fund (a member of The Qatar Foundation) and by the King Abdullah University of Science and Technology (KAUST). The statements made herein are solely the responsibility of the authors.