▎ 摘　　要

We present an approach to monitor and control the strength of the hybridization between electronic states of graphene and metal surfaces. Inspecting the distribution of the pi band in a high-quality graphene layer synthesized on Ni(111) by angle-resolved photoemission, we observe a new "kink" feature that indicates a strong hybridization between the pi and the d states of graphene and nickel, respectively. Upon deposition and gradual intercalation of potassium atoms into the graphene/Ni(111) interface, the kink feature becomes less pronounced, pointing at potassium mediated attenuation of the interaction between the graphene and the substrate.