▎ 摘　　要

The electronic properties of graphene formed on Ni(111) by chemical vapor deposition and intercalated with Cs atoms have been studied by angle-resolved electron-energy-loss spectroscopy. The dispersion curve of pi plasmon, in comparison with the analogous dispersion curve obtained in the absence of intercalated Cs, shows that alkali metal atoms make graphene to be quasi-free, with a much lowered charge transfer, and with the recovery of the pi band linearity at Dirac points. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4798331]