A first-principles study of K adsorption on Pb(111)

Area of Science:

• Surface Science
• Materials Science
• Computational Chemistry

Background:

• Understanding adsorbate behavior on metal surfaces is crucial for catalysis and electronics.
• Lead (Pb) surfaces are of interest due to their unique electronic properties.

Purpose of the Study:

• To investigate the stable structures and bonding characteristics of potassium (K) on the Pb(111) surface.
• To elucidate the electronic and geometric factors governing K adsorption on Pb(111).

Main Methods:

• Ab initio total-energy density functional theory (DFT) calculations.
• Supercell models were used to simulate K adsorption.
• Comparison with experimental Low-Energy Electron Diffraction (LEED) data.

Main Results:

• The substitutional site for K on Pb(111) was found to be more stable than on-surface sites.
• Calculated R30 degrees geometry aligns with experimental LEED observations.
• K adsorption leads to a loss of valence s electrons and a reduced work function due to dipole formation.

Conclusions:

• Potassium adsorption on Pb(111) favors a substitutional configuration.
• The bonding exhibits a mixed ionic and metallic character.
• Adsorption significantly modifies the electronic properties of the Pb(111) surface, notably reducing its work function.