A study on adatom transport through (√3 × √3)-R30°-CH3S self-assembled monolayers on Au(111) using first principles...

Area of Science:

• Surface Science
• Materials Chemistry
• Computational Chemistry

Background:

• Self-assembled monolayers on Au(111) exhibit significant chemical, electrical, and optical properties.
• Gold adatoms are implicated as key contributors to these properties.
• Fundamental understanding of adatom transport within these structures remains limited.

Purpose of the Study:

• To elucidate the migration mechanism of gold adatoms within a CH3S self-assembled structure on Au(111).
• To provide atomistic models for adatom transport in molecular networks.
• To understand the factors influencing adatom mobility in self-assembled monolayers.

Main Methods:

• First-principles calculations were employed to investigate adatom migration.
• Atomistic models were developed to describe the hopping mechanism of Au adatoms.
• The kinetic barrier for adatom migration was compared between the molecular network and a clean Au surface.

Main Results:

• Gold adatoms migrate within the CH3S self-assembled lattice via a hopping mechanism between CH3S species.
• Adatom transport is significantly slowed within the molecular network compared to a clean Au surface.
• The kinetic barrier for migration is higher within the molecular network due to the breaking and formation of Au-S bonds.

Conclusions:

• The mobility of gold adatoms is hindered by the presence of the CH3S molecular network.
• The interaction and dynamics of gold-sulfur bonds are critical to adatom transport.
• These findings provide a basis for understanding defect transport in molecular assemblies and their resulting properties.