Frictionless nanohighways on crystalline surfaces

Area of Science:

• Nanoscale science
• Materials science
• Tribology

Background:

• Understanding nanoscale friction, governed by atomic arrangements, remains incomplete.
• Existing models do not fully capture the complexities of atomic-scale interactions.

Purpose of the Study:

• To provide a unified understanding of nanoscale friction.
• To categorize atomic contacts based on geometrical features and energy potentials.

Main Methods:

• Studying the interlocking potential energy of infinite contacting surfaces with arbitrary lattice symmetries.
• Extending the analysis to finite contacts.
• Categorizing contacts based on geometrical features.

Main Results:

• Identified three types of nanoscale contacts: structurally lubric, corrugated and strongly interlocked, and directionally structurally lubric.
• The directionally structurally lubric contact exhibits frictionless movement along one axis and finite friction along others.
• This novel contact type is energetically stable and shows extreme friction anisotropy.

Conclusions:

• The proposed categorization provides a comprehensive framework for understanding nanoscale friction.
• The findings are applicable to various technologically relevant materials, including 2D materials and colloidal systems.
• This research opens new avenues for designing materials with tailored frictional properties.