Metal Adatom Induced Corrugation of Cu(001)

TL;DR

This study reveals that metal adatoms like Pb or Bi induce significant surface corrugation on Cu(001), caused by charge redistribution, as demonstrated through atom beam scattering experiments, contrasting with weakly chemisorbed adatoms like Hg.

Contribution

The paper demonstrates that metal adatoms induce surface corrugation on Cu(001) via charge redistribution, a novel insight supported by atom beam scattering data.

Findings

Pb and Bi adatoms increase Cu(001) surface corrugation up to ten times.

Corrugation results from charge redistribution, not adsorbate islands.

Weakly chemisorbed adatoms like Hg do not cause corrugation.

Abstract

We report the discovery of a metal adatom induced corrugation of Cu(001) as probed by atom beam scattering (ABS). At Pb or Bi coverages of 0.05 (fraction of Cu layer), and while a (1$\times$1) LEED pattern is still observed, the ABS diffraction pattern from \underbar{uncovered} Cu(001) areas has changed considerably from that of clean Cu(001). We show that these uncovered areas have become up to ten times more corrugated than the clean Cu(001). We performed several carefully designed experiments to test whether our data could be interpreted as a result of scattering from adsorbate islands or from a lattice of randomly occupied sites. Instead, we ascribe the nature of this metal adatom induced corrugation to the redistribution of the Cu(001) surface charge density due to the adsorption of Pb or Bi atoms. No effect is seen following adsorption of weakly chemisorbed adatoms, such as Hg. A model consistent with all our observations is presented.