Synthesis of a weakly bonded graphite monolayer on Ni(111) by intercalation of silver

Silver has been successfully intercalated underneath a monolayer of graphit e (MG) adsorbed on Ni(111)by deposition on the MG/Ni(111)surface at room te mperature and subsequent annealing to 350-400 degrees C. The surface phonon dispersion of the MG/AgNi(111) system has been measured in the <(Gamma)ove r bar>(K) over bar direction of the Brillouin zone using high resolution el ectron energy loss spectroscopy. The dispersion curves were found to be alm ost identical to those of bulk graphite, which is in contrast to the soften ed graphite-like phonon modes observed for the MG/Ni(111) system. This sugg ests that the stiffening of the phonon modes induced by silver intercalatio n is caused by a weaker interaction of the pi states of graphite with the s ubstrate. These results demonstrate that a weakly bonded graphite monolayer , whose chemical properties are very similar to those of bulk graphite and which is stable up to 400 degrees C, can be synthesized in situ on Ni(111) after intercalation of silver.