Self-consistent van der Waals density functional study of benzene adsorption on Si(100)

TL;DR

This study uses the self-consistent van der Waals density functional method to analyze benzene adsorption on Si(100), revealing the most stable structure and emphasizing the importance of accurate molecule-surface interaction modeling.

Contribution

It demonstrates that advanced vdW-DFs accurately predict the preferred benzene adsorption structure on Si(100), aligning with high-level RPA calculations.

Findings

TB structure is more stable than BF according to vdW-DFs

Accurate modeling of molecule-surface interactions is crucial

Molecular deformation significantly influences adsorption stability

Abstract

The adsorption of benzene on the Si(100) surface is studied theoretically using the self-consistent van der Waals density functional (vdW-DF) method. The adsorption energies of two competing adsorption structures, butterfly (BF) and tight-bridge (TB) structures, are calculated with several vdW-DFs at saturation coverage. Our results show that recently proposed vdW-DFs with high accuracy all prefer TB to BF, in accord with more accurate calculations based on exact exchange and correlation within the random phase approximation. Detailed analyses reveal the important roles played by the molecule-surface interaction and molecular deformation upon adsorption, and we suggest that their precise description is prerequisite for accurate prediction of the most stable adsorption structure of organic molecules on semiconductor surfaces.