Robust Superlubricity in Graphene/h-BN Heterojunctions

Area of Science:

• Materials Science
• Tribology
• Condensed Matter Physics

Background:

• The friction properties of layered materials are crucial for applications like dry lubrication.
• Understanding the sliding energy landscape of interfaces is key to controlling friction.
• Graphene and hexagonal boron nitride (h-BN) are atomically thin materials with potential for novel electronic and mechanical applications.

Purpose of the Study:

• To investigate the sliding energy landscape of the heterogeneous graphene/h-BN interface.
• To determine the effect of flake size and lattice mismatch on friction anisotropy.
• To explore the potential of these heterogeneous interfaces for stable low-friction applications.

Main Methods:

• Utilizing the registry index to analyze the sliding energy landscape.
• Simulating the behavior of graphene flakes of varying sizes sliding on h-BN.
• Examining the influence of the misfit angle between graphene and h-BN lattices.

Main Results:

• The anisotropy of sliding energy corrugation decreases as graphene flake size increases.
• For large flakes, sliding energy corrugation is significantly lower than for commensurate lattices.
• A stable low-friction state is predicted for larger graphene flakes on h-BN, unlike homogeneous interfaces.

Conclusions:

• Heterogeneous graphene/h-BN interfaces exhibit size-dependent friction properties.
• These interfaces can achieve stable low-friction states, overcoming limitations seen in homogeneous systems.
• Heterogeneous layered interfaces show significant promise for effective dry lubrication applications.