Evidence for acoustic-like plasmons on epitaxial graphene on Pt(111)

摘要: The dispersion and the damping of sheet plasmon in a graphene monolayer grown on Pt(111) have been studied by using angle-resolved electron energy loss spectroscopy. We found that relation mode confined is linear, as consequence screening metal substrate. Present results demonstrate presence an underlying substrate could striking consequences propagation even case system which exhibits weak graphene-substrate interaction. Moreover, we Landau essentially occurs via interband excitations starting above Fermi wave vector. On contrary, intraband transitions do not significant influence collective mode.