Structural transformations of Cu(110) surface induced by adsorption of molecular chlorine

The adsorption of molecular chlorine on Cu(110) has been studied by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) in the combination with density functional theory (DFT) calculations. We have found that at early stage of chlorine adsorption the reconstruction of the Cu(110) surface takes place. At coverages 0.4 < θ < 0.5 ML (monolayer), an array of the striped light domain walls separating the c(2 × 2) domains forms on the surface. According to DFT calculations, each light domain wall contains an additional row of copper atoms in the middle. As the coverage increases to 0.5 ML, all the light domain walls disappear from the adlayer and a simple c(2 × 2) structure forms. Further chlorine dosing results in the uniaxial splitting of the overlayer spots in LEED indicating the compression of the chlorine layer in the 〈110〉 direction. At coverages close to the saturation level, the adsorption of chlorine leads to formation of 1D facets consisting of two {210} planes and running along the [001] direction.