Dimer-Anticorrelation-Induced Stabilization of Adsorbate Clustering on theSi(100)−(2×1)Surface

Abstract

It is well established that absorbate-absorbate interactions play a key role in determining the distribution of adsorbates on surfaces. In cases where these interactions are repulsive adsorbates frequently arrange so as to minimize these unfavorable interactions. This simple picture, however, neglects the influence of adsorption on the properties on the underlying substrate. Here, using STM, we show that on Si(100) many intrinsically repulsive adsorbates cluster to form surface patches even at low surface coverages. With the aid of density functional theory calculations and Monte Carlo simulations, we show that patch formation is an intrinsic property of the Si(100) surface that is driven by the energy lowering associated with the formation of extended regions of bare dimers. The enhanced attraction between anticorrelated tilted bare dimers is sufficient to offset the repulsions between adsorbates.

Evaluating Mechanisms of Adsorbate Induced Roughening in Si(100) with Monte Carlo Simulations

“…However, Cl adsorbed on Si(100) appears to be distributed uniformly on the surface indicating that there is no repulsion among adsorbates. After a detailed analysis of the experiments, Chen and Boland [15] showed that having two filled dimers next to each other in the same dimer row is energetically favorable by only 0.005 eV. Interestingly, similar calculations for hydrogen-filled dimers, which do not present a steric repulsion, show a clustering energy of 0.051 eV, in accord with other reported values.…”

“…In Refs. [15][16][17], the authors attribute this finding to the energy associated to anticorrelated tilted bare dimers. In Ref.…”

Halogen chemisorption, the pairwise diffusion of I, and trapping by defects on Si(100)

“…This follows from energy considerations that involve anticorrelated dimer buckling [24,25]. Chen and Boland recently considered the attractive interaction between anticorrelated buckled dimers [26]. Halogen adsorbates quench that buckling and, hence, the attraction.…”

Determination of dissociative fragment-adsorbate interaction energy during chemisorption of the diatomic molecule HCl on Si(100)

“…6 AAIs are typically weaker than ASIs but can lead to reconstructions or pattern formations on surfaces. 3,7,8 AAIs also change the sticking probabilities of molecules and the diffusivities of adsorbates. 9,10 Often omitted in discussions of a surface process is that the single term "adsorbate" in AAIs and ASIs can refer to several species and to several bonding conditions and that AAIs and ASIs may vary from place to place on a surface, depending on the local adsorbate distributions.…”

“…The fragment-adsorbate interactions between Cl and H and between H and H are assumed to be negligible. 8 The effective substrate interaction U ef f experienced by the Cl fragment is the sum of the four energies U 0s ͑s =1-4͒. In Figs.…”