Dresden 2009 – scientific programme
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O: Fachverband Oberflächenphysik
O 56: Metal substrates: Epitaxy, growth and adsorbates
O 56.2: Talk
Thursday, March 26, 2009, 15:15–15:30, SCH A316
Evidence for Cu dimer mobility on Cu(001) — •Anja Michl, Andreas Dobler, and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen
We investigated the homoepitaxial submonolayer growth of Cu on Cu(001) at 300 K. The density of stable Cu islands nx was measured by scanning tunneling microscopy after thermal deposition at pressures below 5 × 10−11 mbar.
Variation of coverage θ and particle flux F lead to a characteristic behavior of nx ∝ θ0.20± 0.05 for θ ≤ 0.11 ML and nx ∝ F0.40 ± 0.02 at saturation for F = 10−5 to 10−2 ML/s. This result is not compatible with standard models of nucleation which predict an exponent i/(i+2) for the flux dependence with the atom number i of the largest unstable islands.
A recent theoretical study [1] concludes that dimer mobility is dominant at 300 K in the experimentally available range of flux. The predicted behavior nx ∝ θ1/5 and nx ∝ F2/5 is in excellent agreement with our experimental results.
[1] P. A. Mulheran and M. Basham, Phys. Rev. B 77 (2008) 075427