Controlling the Electronic Structure of Graphene Using Surface-Adsorbate Interactions
University of Wisconsin-Madison Madison United States
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Hybridization of atomic orbitals in graphene on Ni111 opens a large energy gap of 2.8 eV between non-hybridized states at the K-point. Here we use alkali metal adsorbate to reduce and even eliminate this energy gap, and also identify a mechanism responsible for decoupling graphene from the Ni substrate without intercalation of atomic species underneath graphene. Using angle-resolved photoemission spectroscopy and density functional theory calculations, we show that the energy gap is reduced to 1.3 eV due to moderate decoupling after adsorption of Na on top of graphene.