Charge Density Evolution Governing Interfacial Friction.

Area of Science:

• Surface Science
• Tribology
• Condensed Matter Physics

Background:

• The electron nature of solids significantly influences contact system properties.
• General rules governing electron coupling in interfacial friction are not well-established.
• Understanding interfacial friction is crucial for materials science and nanotechnology.

Purpose of the Study:

• To investigate the physical origins of friction in solid interfaces.
• To establish a model for interfacial friction based on electronic interactions.
• To explore the relationship between electronic evolution and frictional energy dissipation.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• Analysis of electron density variations along sliding pathways.
• Tracking frictional energy dissipation during slip.

Main Results:

• Interfacial friction is linked to electronic barriers hindering contact configuration changes.
• Frictional energy dissipation exhibits a linear dependence on electronic evolution.
• A charge evolution model correlates friction with electronic rearrangement.
• The model provides insights into shear strength and the real contact area hypothesis.

Conclusions:

• Electronic interactions fundamentally govern interfacial friction across various bond types (van der Waals, metallic, ionic, covalent).
• The charge evolution model offers a new perspective on friction at the electronic level.
• This work paves the way for designing nanomechanical devices and understanding natural fault mechanics.