Berlin 2005 – scientific programme

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O: Oberflächenphysik

O 18: Adsorption an Oberfl
ächen II

O 18.7: Talk

Saturday, March 5, 2005, 12:15–12:30, TU EB301

Adsorbate induced surface stress for (2× 1)O on Cu(110) measured with an STM — •Christian Bombis, Marina Moiseeva, and Harald Ibach — Institut für Schichten und Grenzflächen ISG 3, Forschungszentrum Jülich GmbH, 52425 Jülich

The formation of the so-called (2× 1) oxygen stripe phase on Cu(110) is imaged in situ with an STM and simultaneously a quantitative determination of the induced surface stress is accomplished. For this intention the bending bar technique is utilized with the bending measured by the STM. Due to the anisotropy of the Cu(110) surface, two experiments, one with the [110] -direction and a second with the [001]-direction along the bar have to be carried out for a quantitative analysis of the induced surface stress. From the two experiments we calculate the induced surface stress. We find that the difference Δτ of the surface stresses of the (2× 1)O phase on Cu(110) and the clean Cu(110) surface is compressive for both directions, in accordance with the adsorption of oxygen on other surfaces. The stress depends significantly on the coverage. Orthogonal to the oxygen stripes ( [110]-direction) the data can be fitted to Δτ_[110]≈(−0,24−1,7× e^−2,5×θ_s) Nm⁻¹ and parallel to the stripes ([001]-direction) to Δτ_[001]≈(−0,37−2,65× e^{−2,52×θ_s}) Nm⁻¹ .