Slider thickness promotes lubricity: from 2D islands to 3D clusters

Area of Science:

• Nanotribology
• Surface Science
• Materials Science

Background:

• Understanding friction at the nanoscale is crucial for various applications.
• The behavior of adsorbed atomic clusters and islands on surfaces differs in friction.
• Specific differences in static friction between gold islands and clusters on graphite are not well understood.

Purpose of the Study:

• To investigate the static friction of gold on graphite using molecular dynamics simulations.
• To explore how gold thickness influences friction for islands versus clusters.
• To identify the key factors contributing to thickness-induced lubricity.

Main Methods:

• Realistic molecular dynamics simulations.
• Modeling static friction of gold (Au) on graphite (Gr).
• Analysis of friction as a function of gold film thickness.

Main Results:

• Static friction decreases progressively with increasing gold thickness.
• Clusters exhibit lower static friction than monolayer islands.
• Increased effective rigidity and larger lateral contact size in clusters reduce interdigitation and enhance lubricity.

Conclusions:

• Gold thickness significantly impacts static friction, with thicker films being more lubric.
• Clusters are more lubric than islands due to reduced interdigitation and better accommodation of interface solitons.
• Findings have broad implications for nanotribological systems involving static and dynamic friction.