Moiré-like distribution of local tunneling barrier height of the monolayer graphite adsorbed on Pt(111) surface

The Moiré-like distribution of the local tunneling barrier height (LBH) in the surface of monolayer graphite (MG) adsorbed on Pt(111) is discussed on the basis of atom-resolved LBH imaging. The Moiré-like LBH distribution is explained by the local work function distribution induced by the lateral variations of inter-layer interaction between C and Pt atoms, which results from the lattice mismatch between MG and Pt(111). Further, the tip-sample distance dependence of the LBH image is discussed. When the tip-sample separation is improperly small, we find that the apparent LBH is influenced by the surface deformation induced by the interaction between the tip and the sample, resulting in the reversal of the Moiré-like contrast. This is also explained in the framework of the inhomogeneous inter-layer interaction.